JP7522652B2 - Auxiliary power supplies, power supplies, and medical systems - Google Patents

Description

The present invention relates to an auxiliary power supply device, a power supply device, and a medical system.

Research and development is being conducted on technology to protect the load connected to a power supply device in the event that the power supply to the power supply device is cut off due to a power outage or other cause.

In this regard, a power supply device is known that has a smoothing circuit section between the output side of the rectifier circuit section and the input side of the switching power supply section, which smoothes the output of the rectifier circuit section and supplies the smoothed output to the switching power supply section, and that can add a second capacitance to the first capacitance of the smoothing circuit section, which extends the output holding time of the switching power supply section when the supply of AC power to the rectifier circuit section is cut off (see Patent Document 1). The output holding time is the time during which the switching power supply section is capable of holding an output when the supply of AC power to the rectifier circuit section is cut off.

Japanese Patent Application Publication No. 10-004674

It is known that a power supply device such as that described in Patent Document 1 cannot control the timing of protecting a connected load (e.g., a motor) in the event of a power outage or the like. For this reason, the power supply device may not be able to protect the load in such a case.

To solve this problem, a method is known in which a voltage drop in the aforementioned second capacitance is detected and a state occurs in which the supply of AC power to the rectifier circuit is cut off. This method utilizes the fact that the voltage of the second capacitance drops when power is supplied from the second capacitance to the switching power supply to extend the output holding time in that state. However, with this method, the larger the second capacitance is, the longer it takes to detect a voltage drop in the second capacitance, and there are cases in which it is not possible to notify the occurrence of that state at the desired timing.

The present invention has been made in consideration of the above circumstances, and aims to provide an auxiliary power supply device that can maintain output from the power supply device for a predetermined period of time when the power supply to the power supply device is cut off, and can more reliably notify at a desired timing that the power supply to the power supply device has been cut off and that power has been supplied to the power supply device from the auxiliary power supply device.

One aspect of the present invention is an auxiliary power supply device connected to both terminals of a smoothing capacitor of a power supply device having a primary side smoothing capacitor, the auxiliary power supply device comprising: a first power supply terminal connected to a first smoothing capacitor terminal of the smoothing capacitor; a second power supply terminal connected to a second smoothing capacitor terminal of the smoothing capacitor; a first capacitor connected between the first power supply terminal and the second power supply terminal, charged by supplying power to the power supply device and discharging a discharge current in response to the discharge of the smoothing capacitor; and a switch circuit unit having a switch element that switches between an on state and an off state in response to the discharge current discharged from the first capacitor.

According to the present invention, when the power supply to the power supply device is interrupted, the output from the power supply device can be maintained for a predetermined period of time, and the fact that the power supply to the power supply device has been interrupted can be notified more reliably at a desired timing.

1 is a diagram showing an example of a configuration of an auxiliary power supply device 1 according to an embodiment; FIG. 11 is a diagram showing an example of a configuration of an auxiliary power supply device 1 according to a second modified example of the embodiment. FIG. 11 is a diagram showing an example of a configuration of an auxiliary power supply device 1 according to a third modified example of the embodiment. 1 is a diagram showing an example of the configuration of a power supply device PS to which an auxiliary power supply device 1 is connected. 11 is a diagram showing another example of the configuration of a power supply device PS to which the auxiliary power supply device 1 is connected. FIG. 13 is a diagram showing yet another example of the configuration of a power supply device PS to which the auxiliary power supply device 1 is connected. FIG. FIG. 11 is a diagram showing an example of a configuration of an auxiliary power supply device 1 according to a fourth modified example of the embodiment. FIG. 13 is a diagram showing an example of a configuration of an auxiliary power supply device 1 according to a fifth modified example of the embodiment. FIG. 13 is a diagram showing an example of a configuration of an auxiliary power supply device 1 according to a sixth modified example of the embodiment.

<Embodiment>
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Here, in the embodiment, a conductor that transmits an electric signal corresponding to DC power or an electric signal corresponding to AC power will be referred to as a transmission line and described. The transmission line may be, for example, a conductor printed on a substrate, a conductor formed in a linear shape, or another conductor. In addition, in the embodiment, when it is referred to as a voltage, it means a potential difference from a predetermined reference potential, and illustration and description of the reference potential are omitted. Here, the reference potential may be any potential. In the embodiment, as an example, a case where the reference potential is the ground potential will be described. In addition, in the embodiment, for convenience of explanation, a state in which a certain field effect transistor has a current flowing between the drain terminal and the source terminal, and a state in which a certain phototransistor has a current flowing between the collector terminal and the emitter terminal will be described as an on state. Also, in the embodiments, for convenience of explanation, a state in which no current flows between the drain terminal and the source terminal of a certain field effect transistor, and a state in which no current flows between the collector terminal and the emitter terminal of a certain phototransistor will each be referred to as an off state.

<Outline of the auxiliary power supply device>
First, an outline of an auxiliary power supply device according to an embodiment will be described. The auxiliary power supply device is a device connected to both terminals of a smoothing capacitor of a power supply device having a smoothing capacitor on the primary side. Here, when the supply of power to the power supply device is interrupted due to an influence of a power outage or the like, the smoothing capacitor is discharged. In such a case, the auxiliary power supply device supplies power to the smoothing capacitor, and maintains the supply of power from the power supply device to a load connected to the power supply device for a predetermined time.

The auxiliary power supply device according to the embodiment includes a first power supply terminal connected to a first smoothing capacitor terminal of both terminals of the smoothing capacitor of the power supply device, a second power supply terminal connected to a second smoothing capacitor terminal of both terminals of the smoothing capacitor, a first capacitor, and a switch circuit unit. Here, the first capacitor is connected between the first power supply terminal and the second power supply terminal. The first capacitor is charged by supplying power to the power supply device. The first capacitor discharges a discharge current in response to the discharge of the smoothing capacitor. The switch circuit unit has a switch element that switches between an on state and an off state in response to the discharge current discharged from the first capacitor. This allows the auxiliary power supply device to hold the output from the power supply device for a predetermined period of time when the supply of power to the power supply device is interrupted, and can more reliably notify the interruption of the supply of power to the power supply device at a desired timing by switching the state of the switch element. As a result, the auxiliary power supply device can more reliably protect the load connected to the power supply device in this case.

The circuit configuration of the auxiliary power supply device according to the embodiment and the operation of the auxiliary power supply device are described in detail below. Specific examples of power supply devices to which the auxiliary power supply device is connected are also described below.

<Configuration of auxiliary power supply device>
Hereinafter, a configuration of an auxiliary power supply device 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of an auxiliary power supply device 1 according to an embodiment.

The auxiliary power supply device 1 is an example of the aforementioned auxiliary power supply device. The auxiliary power supply device 1 is connected to a power supply device PS (not shown). More specifically, the auxiliary power supply device 1 is connected to both ends of a smoothing capacitor SC on the primary side of the power supply device PS. Here, the power supply device PS may be any power supply device that has a smoothing capacitor SC, for example, a switching power supply device having a transformer.

The auxiliary power supply device 1 can also be connected to an external device. In the example shown in FIG. 1, an external device EX is connected to the auxiliary power supply device 1, as an example. The external device EX is a device that can notify the power supply device PS of a cutoff in the event that the power supply to the power supply device PS is cut off. The configuration of the external device EX will be described later.

The auxiliary power supply device 1 has four terminals, namely, a power supply terminal T1, a power supply terminal T2, a signal terminal T3, and a signal terminal T4. The auxiliary power supply device 1 also has a charge/discharge circuit section CT1, a constant voltage circuit section CT2, a discharge current detection circuit section CT3, a delay circuit section CT4, and a switch circuit section CT5. The auxiliary power supply device 1 may not have the delay circuit section CT4. The auxiliary power supply device 1 may also have other terminals in addition to the four terminals, namely, the power supply terminal T1, the power supply terminal T2, the signal terminal T3, and the signal terminal T4, as long as the functions of the auxiliary power supply device 1 described in this embodiment are not impaired. The auxiliary power supply device 1 may also have other circuit sections, other devices, etc. in addition to the charge/discharge circuit section CT1, the constant voltage circuit section CT2, the discharge current detection circuit section CT3, the delay circuit section CT4, and the switch circuit section CT5.

Here, the charge/discharge circuit section CT1 has four terminals, namely, input terminal CT11, input terminal CT12, output terminal CT13, and output terminal CT14. The constant voltage circuit section CT2 has four terminals, namely, input terminal CT21, input terminal CT22, output terminal CT23, and output terminal CT24. The discharge current detection circuit section CT3 has five terminals, namely, input terminal CT31, input terminal CT32, output terminal CT33, output terminal CT34, and output terminal CT35. The delay circuit section CT4 has five terminals, namely, input terminal CT41, input terminal CT42, input terminal CT43, output terminal CT44, and output terminal CT45. In addition, the switch circuit section CT5 has four terminals: an input terminal CT51, an input terminal CT52, a signal terminal CT53, and a signal terminal CT54.

The power supply terminal T1 is a terminal connected to the first smoothing capacitor terminal of the smoothing capacitor SC. Here, the first smoothing capacitor terminal refers to one of the two terminals of the smoothing capacitor SC. The power supply terminal T1 is also connected to the input terminal CT11 of the charge/discharge circuit section CT1 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the power supply terminal T1 and the input terminal CT11 as long as this does not impair the function of the auxiliary power supply device 1.

The power supply terminal T2 is a terminal connected to the second smoothing capacitor terminal of the smoothing capacitor SC. Here, the second smoothing capacitor terminal is the other of the two terminals of the smoothing capacitor SC. The power supply terminal T2 is also connected to the input terminal CT12 of the charge/discharge circuit section CT1 via a transmission path. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the power supply terminal T2 and the input terminal CT12 as long as this does not impair the function of the auxiliary power supply device 1.

The output terminal CT13 of the charge/discharge circuit section CT1 is connected to the input terminal CT21 of the constant voltage circuit section CT2 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the output terminal CT13 and the input terminal CT21 as long as the function of the auxiliary power supply device 1 is not impaired.

The output terminal CT14 of the charge/discharge circuit section CT1 is connected to the input terminal CT22 of the constant voltage circuit section CT2 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the output terminal CT14 and the input terminal CT22 as long as the function of the auxiliary power supply device 1 is not impaired.

The output terminal CT23 of the constant voltage circuit section CT2 is connected to the input terminal CT31 of the discharge current detection circuit section CT3 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the output terminal CT23 and the input terminal CT31 as long as the function of the auxiliary power supply device 1 is not impaired.

The output terminal CT24 of the constant voltage circuit section CT2 is connected to the input terminal CT32 of the discharge current detection circuit section CT3 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the output terminal CT24 and the input terminal CT32 as long as the function of the auxiliary power supply device 1 is not impaired.

The output terminal CT33 of the discharge current detection circuit section CT3 is connected to the input terminal CT41 of the delay circuit section CT4 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the output terminal CT33 and the input terminal CT41 as long as the function of the auxiliary power supply device 1 is not impaired.

The output terminal CT34 of the discharge current detection circuit section CT3 is connected to the input terminal CT42 of the delay circuit section CT4 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the output terminal CT34 and the input terminal CT42 as long as the function of the auxiliary power supply device 1 is not impaired.

The output terminal CT35 of the discharge current detection circuit section CT3 is connected to the input terminal CT43 of the delay circuit section CT4 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the output terminal CT35 and the input terminal CT43 as long as the function of the auxiliary power supply device 1 is not impaired.

The output terminal CT44 of the delay circuit section CT4 is connected to the input terminal CT51 of the switch circuit section CT5 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the output terminal CT44 and the input terminal CT51 as long as the function of the auxiliary power supply device 1 is not impaired.

The output terminal CT45 of the delay circuit section CT4 is connected to the input terminal CT52 of the switch circuit section CT5 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the output terminal CT45 and the input terminal CT52 as long as the function of the auxiliary power supply device 1 is not impaired.

The signal terminal CT53 of the switch circuit section CT5 is connected to the signal terminal T3 of the auxiliary power supply device 1 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the signal terminals CT53 and T3 as long as the function of the auxiliary power supply device 1 is not impaired.

The signal terminal CT54 of the switch circuit section CT5 is connected to the signal terminal T4 of the auxiliary power supply device 1 via a transmission line. Note that other circuit sections, other circuit elements, other devices, etc. may be connected between the signal terminals CT54 and T4 as long as the function of the auxiliary power supply device 1 is not impaired.

The signal terminals T3 and T4 of the auxiliary power supply device 1 are terminals connected to the external device EX described above. The external device EX has, for example, a power supply circuit with a display function provided therein. In the example shown in FIG. 1, the external device EX has a power supply circuit having a resistor element EX1, a light-emitting diode EX2, and a DC voltage source EX3 provided therein. One of the two terminals of the resistor element EX1 is connected to the signal terminal T3 via a transmission line. The other of the two terminals of the resistor element EX1 is connected to the cathode of the light-emitting diode EX2 via a transmission line. The anode of the light-emitting diode EX2 is connected to the positive terminal of the DC voltage source EX3 via a transmission line. The negative terminal of the DC voltage source EX3 is connected to the signal terminal T4 via a transmission line.

When the external device EX is connected to the auxiliary power supply device 1, the power supply circuit as described above is connected to the signal terminals T3 and T4 of the auxiliary power supply device 1. As a result, a voltage is applied between the signal terminals T3 and T4 from the power supply circuit. However, as described later, a phototransistor PT is provided on the transmission path connecting the signal terminals T3 and T4 in the switch circuit section CT5. The state of the phototransistor PT is in the OFF state when the supply of power to the power supply device PS is cut off. Therefore, the voltage level at both ends of the transmission path, that is, the voltage level between the signal terminals T3 and T4, becomes the H level when the supply of power to the power supply device PS is cut off. As a result, no current flows through the light-emitting diode EX2 of the external device EX. That is, the light-emitting diode EX2 does not emit light (is turned off) in this case. On the other hand, the state of the phototransistor PT is in the ON state when the supply of power to the power supply device PS is not cut off. Therefore, the voltage level at both ends of the transmission path, i.e., the voltage level between the signal terminal T3 and the signal terminal T4, becomes the L level when the power supply to the power supply device PS is not cut off. As a result, a current flows through the light-emitting diode EX2 of the external device EX. That is, the light-emitting diode EX2 emits light in this case. As a result, in the external device EX, when the power supply to the power supply device PS is not cut off, the light-emitting diode EX2 emits light, and when the power supply to the power supply device PS is cut off, the light-emitting diode EX2 does not emit light (goes out). This allows the external device EX to notify that the power supply to the power supply device PS has been cut off. In other words, the auxiliary power supply device 1 can more reliably notify that the power supply to the power supply device PS has been cut off at a desired timing by switching the state of the phototransistor PT of the switch circuit section CT5. The external device EX is, for example, an information processing device such as a microcomputer, but is not limited to this. Note that the display function of the external device EX may be realized, for example, by other circuit elements, other devices, etc., instead of by the light-emitting diode EX2.

When the auxiliary power supply device 1 does not include the delay circuit section CT4, the discharge current detection circuit section CT3 may be configured not to have the output terminal CT35. In this case, the output terminal CT33 of the discharge current detection circuit section CT3 is connected to the input terminal CT51 of the switch circuit section CT5. In this case, the output terminal CT34 of the discharge current detection circuit section CT3 is connected to the input terminal CT52 of the switch circuit section CT5 via a resistive element or without a resistive element.

The phototransistor PT of the switch circuit section CT5 may be configured to be in an off state when the supply of power to the power supply device PS is not cut off, and to be in an on state when the supply of power to the power supply device PS is cut off.

<Circuit configuration of charge/discharge circuit>
The circuit configuration of the charge/discharge circuit section CT1 will be described below.

The charge/discharge circuit section CT1 includes, for example, a capacitor C1, a resistive element R1, and a diode D1.

The input terminal CT11 of the charge/discharge circuit section CT1 is connected to one of the two terminals of the capacitor C1 and the output terminal CT13 via a transmission line. The other of the two terminals of the capacitor C1 is connected to one of the two terminals of the resistor element R1, the cathode of the diode D1, and the output terminal CT14 via a transmission line. The other of the two terminals of the resistor element R1 and the anode of the diode D1 are connected to the input terminal CT12 of the charge/discharge circuit section CT1 via a transmission line. That is, the diode D1 and the resistor element R1 are connected in parallel between the capacitor C1 and the input terminal CT12. However, the diode D1 is connected in parallel with the resistor element R1 between the capacitor C1 and the input terminal CT12 so as to pass a current in the direction from the input terminal CT12 to the capacitor C1. In other words, in the charge/discharge circuit section CT1, the direction in which the diode D1 passes current is from the input terminal CT12 to the capacitor C1. In other words, in the auxiliary power supply device 1, the direction in which the diode D1 passes current is from the input terminal CT12 connected to the power supply terminal T2 to the capacitor C1. Note that the charge/discharge circuit section CT1 may be configured to include other circuit elements, other devices, etc. in addition to the capacitor C1, the resistor element R1, and the diode D1, or in place of some or all of the capacitor C1, the resistor element R1, and the diode D1, as long as the functions of the charge/discharge circuit section CT1 described in this embodiment are not impaired.

<Operation of the charge/discharge circuit>
The operation of the charge/discharge circuit section CT1 will now be described. The charge/discharge circuit section CT1 performs at least two operations, charging the capacitor C1 and discharging the capacitor C1, depending on the state of the power supply PS.

When power is being supplied to the power supply PS, a voltage is applied between the power supply terminal T1 and the power supply terminal T2 from the smoothing capacitor SC described above. The power supply terminal T1 is the high-voltage power supply terminal of the power supply terminals of the auxiliary power supply device 1. The power supply terminal T2 is the low-voltage power supply terminal of the power supply terminals of the auxiliary power supply device 1. Therefore, in this state, the capacitor C1 of the charge/discharge circuit section CT1 is charged. In other words, the capacitor C1 is charged by the power being supplied to the power supply PS. When the capacitor C1 is charged, a charging current flows through the resistance element R1 from the capacitor C1 toward the input terminal CT12 (i.e., toward the power supply terminal T2).

On the other hand, when the power supply to the power supply device PS is cut off, if the voltage of the smoothing capacitor SC drops below the voltage of the capacitor C1, a voltage is applied between the power supply terminal T1 and the power supply terminal T2 from the capacitor C1. In this case, a forward voltage is generated across both ends of the diode D1. A current flows from the input terminal CT12 to the capacitor C1 through the diode D1. This current is a discharge current discharged from the capacitor C1. That is, since the charge/discharge circuit unit CT1 includes a resistive element R1 and a diode D1, the capacitor C1 discharges a discharge current to the smoothing capacitor SC in response to the discharge of the smoothing capacitor SC. Naturally, when the input terminal CT11 is connected to the power supply terminal T1 and the input terminal CT12 is connected to the power supply terminal T2, the capacitor C1 discharges a discharge current to the smoothing capacitor SC in response to the discharge of the smoothing capacitor SC. The discharge current discharged from the capacitor C1 in this manner is detected by the discharge current detection circuit unit CT3, which will be described later.

<Circuit configuration of constant voltage circuit>
The circuit configuration of the constant voltage circuit section CT2 will be described below.

The constant voltage circuit section CT2 includes a capacitor C2, a resistor element R2, a resistor element R3, a resistor element R4, a diode D2, a switch element S1, a Zener diode ZD1, and a Zener diode ZD2.

In the following, as an example, a case where the switch element S1 is an N-channel field effect transistor will be described. Instead of an N-channel field effect transistor, the switch element S1 may be another switch element such as a P-channel field effect transistor, a bipolar transistor, or a relay switch.

The input terminal CT21 of the constant voltage circuit unit CT2 is connected to one of the two terminals of the resistor element R2 and one of the two terminals of the resistor element R3 via a transmission line. The other of the two terminals of the resistor element R2 is connected to the cathode of the Zener diode ZD1 and the gate terminal of the switch element S1 via a transmission line. The anode of the Zener diode ZD1 is connected to one of the two terminals of the resistor element R4, the cathode of the Zener diode ZD2, the output terminal CT23 of the constant voltage circuit unit CT2, and one of the two terminals of the capacitor C2 via a transmission line. The other of the two terminals of the resistor element R4 is connected to the source terminal of the switch element S1 via a transmission line. The drain terminal of the switch element S1 is connected to the cathode of the diode D2 via a transmission line. The anode of the diode D2 is connected to the other of the two terminals of the resistor element R3 via a transmission line. The anode of the Zener diode ZD2 and the other of the two terminals of the capacitor C2 are connected to the input terminal CT22 of the constant voltage circuit unit CT2 and the output terminal CT24 of the constant voltage circuit unit CT2 via a transmission line. In addition to the capacitor C2, the resistor element R2, the resistor element R3, the resistor element R4, the diode D2, the switch element S1, the Zener diode ZD1, and the Zener diode ZD2, or in place of some or all of the capacitor C2, the resistor element R2, the resistor element R3, the resistor element R4, the diode D2, the switch element S1, the Zener diode ZD1, and the Zener diode ZD2, the constant voltage circuit unit CT2 may be configured to include other circuit elements, other devices, etc., as long as the functions of the constant voltage circuit unit CT2 described in this embodiment are not impaired.

<Operation of constant voltage circuit>
The operation of the constant voltage circuit section CT2 will now be described.

The constant voltage circuit CT2 passes a constant current of a predetermined magnitude according to the voltage applied from the smoothing capacitor SC of the power supply PS or the voltage applied from the capacitor C1. The voltage at the output terminal CT23 is made constant by the Zener diode ZD2. The magnitude of the current in the constant voltage circuit CT2 is determined by the voltage generated in the resistance element R4 (the Zener voltage of the Zener diode ZD1 minus the gate-source voltage of the switch element S1). The output voltage of the constant voltage circuit CT2 is also used by the delay circuit CT4 and the switch circuit CT5 (described later) to drive the discharge current detection circuit CT3.

<Circuit configuration of discharge current detection circuit>
The circuit configuration of the discharge current detection circuit section CT3 will be described below.

The discharge current detection circuit section CT3 includes a resistive element R5, a resistive element R6, a diode D3, a diode D4, a diode D5, and a comparator CP1.

The input terminal CT31 of the discharge current detection circuit unit CT3 is connected to one of the two terminals of the resistance element R5, the cathode of the diode D4, the positive power supply terminal of the comparator CP1, and the output terminal CT33 of the discharge current detection circuit unit CT3 via a transmission line. The other of the two terminals of the resistance element R5 is connected to the anode of the diode D3 and the inverting input terminal of the comparator CP1 via a transmission line. The cathode of the diode D3 is connected to the input terminal CT32 of the discharge current detection circuit unit CT3, the anode of the diode D5, the negative power supply terminal of the comparator CP1, and the output terminal CT35 of the discharge current detection circuit unit CT3 via a transmission line. The cathode of the diode D5 is connected to the anode of the diode D4, the non-inverting input terminal of the comparator CP1, and one of the two terminals of the resistor element R6 via a transmission line. The other of the two terminals of the resistor element R6 is connected to the power supply terminal T2 of the auxiliary power supply device 1 via a transmission line. However, in order to prevent the diagram from becoming complicated, the transmission line connecting the resistor element R6 and the power supply terminal T2 is omitted in Fig. 1. The output terminal of the comparator CP1 is connected to the output terminal CT34 of the discharge current detection circuit section CT3 via a transmission line. In addition, the discharge current detection circuit unit CT3 may be configured to include other circuit elements, other devices, etc. in addition to the resistive element R5, resistive element R6, diode D3, diode D4, diode D5, and comparator CP1, or in place of some or all of the resistive element R5, resistive element R6, diode D3, diode D4, diode D5, and comparator CP1, as long as the functions of the discharge current detection circuit unit CT3 described in this embodiment are not impaired.

<Operation of the discharge current detection circuit>
The operation of the discharge current detection circuit unit CT3 will be described below. Here, as an example, the case where the comparator CP1 is an open collector type comparator will be described below. Note that the comparator CP1 may be a totem pole type comparator instead of an open collector type comparator.

As mentioned above, the discharge current detection circuit unit CT3 detects the discharge current discharged from the capacitor C1 of the charge/discharge circuit unit CT1.

Specifically, when power is supplied to the power supply PS, the inverting input terminal of the comparator CP1 is supplied with a forward voltage generated in the diode D3 by applying the voltage output from the constant voltage circuit unit CT2 to the series circuit of the resistor element R5 and the diode D3. This voltage is the reference voltage of the comparator CP1 described above. In this case, since no forward voltage is generated in the diode D1 of the charge/discharge circuit unit CT1, a voltage of 0 [V] is supplied to the non-inverting input terminal of the comparator CP1. As a result, the signal level of the output terminal of the comparator CP1 becomes the L level. On the other hand, even when the supply of power to the power supply PS is cut off, the inverting input terminal of the comparator CP1 is supplied with a forward voltage generated in the diode D3 by applying the voltage output from the constant voltage circuit unit CT2 to the series circuit of the resistor element R5 and the diode D3. However, in this case, the non-inverting input terminal of the comparator CP1 is supplied with a forward voltage of the diode D1 corresponding to the discharge current discharged from the capacitor C1. At this time, the voltage supplied to the non-inverting input terminal of comparator PC1 becomes higher than the forward voltage generated in diode D3. As a result, in this case, the signal level of the output terminal of comparator CP1 becomes H level.

In this way, when the discharge current is discharged from the capacitor C1, the discharge current detection circuit unit CT3 outputs an H level signal. In other words, the discharge current detection circuit unit CT3 detects the difference between the forward voltage of the diode D3 and the forward voltage of the diode D1, inverts the output signal level of the comparator CP1 from an L level to an H level, and detects that the discharge current has been discharged from the capacitor C1.

<Circuit configuration of delay circuit section>
The circuit configuration of the delay circuit section CT4 will now be described.

The delay circuit section CT4 includes a capacitor C3, a resistor element R7, a resistor element R8, a resistor element R9, a resistor element R10, a resistor element R11, a resistor element R12, and a comparator CP2.

The input terminal CT41 of the delay circuit unit CT4 is connected to one of the two terminals of the resistor element R8, one of the two terminals of the resistor element R10, the positive power supply terminal of the comparator CP2, and the output terminal CT44 of the delay circuit unit CT4 through a transmission line. The other of the two terminals of the resistor element R8 is connected to one of the two terminals of the resistor element R7, one of the two terminals of the resistor element R9, one of the two terminals of the capacitor C3, and the non-inverting input terminal of the comparator CP2 through a transmission line. The other of the two terminals of the resistor element R7 is connected to the input terminal CT42 of the delay circuit unit CT4 through a transmission line. The other of the two terminals of the resistor element R10 is connected to one of the two terminals of the resistor element R11 and the inverting input terminal of the comparator CP2 through a transmission line. The other of the two terminals of the resistor element R9 is connected to an input terminal CT43 of the delay circuit section CT4, the other of the two terminals of the capacitor C3, the other of the two terminals of the resistor element R11, and the negative power supply terminal of the comparator CP2 via a transmission line. The output terminal of the comparator CP2 is connected to one of the two terminals of the resistor element R12 via a transmission line. The other of the two terminals of the resistor element R12 is connected to an output terminal CT45 of the delay circuit section CT4 via a transmission line. In addition, the delay circuit unit CT4 may be configured to include other circuit elements, other devices, etc. in addition to the capacitor C3, the resistor element R7, the resistor element R8, the resistor element R9, the resistor element R10, the resistor element R11, the resistor element R12, and the comparator CP2, or in place of some or all of the capacitor C3, the resistor element R7, the resistor element R8, the resistor element R9, the resistor element R10, the resistor element R11, the resistor element R12, and the comparator CP2, as long as the functions of the delay circuit unit CT4 described in this embodiment are not impaired.

<Operation of the delay circuit>
The operation of the delay circuit unit CT4 will be described below. Here, as an example, the case where the comparator CP2 is an open collector type comparator will be described below. Note that the comparator CP2 may be a totem pole type comparator instead of an open collector type comparator.

When the discharge current detection circuit CT3 detects the discharge current discharged from the capacitor C1, the delay circuit CT4 sets the signal level to H level after a predetermined time has elapsed.

Specifically, when power is supplied to the power supply PS, the inverting input terminal of the comparator CP2 is supplied with a voltage obtained by dividing the output voltage of the output terminal CT23 (the voltage of the Zener diode ZD2) by the resistor elements R10 and R11. This voltage is the reference voltage of the comparator CP2. In this case, the non-inverting input terminal of the comparator CP2 is supplied with a voltage corresponding to the signal, since the L-level signal of the output terminal of the comparator CP1 is supplied from the discharge current detection circuit unit CT3 to the input terminal CT42 of the delay circuit unit CT4. Here, the voltage is lower than the voltage supplied to the inverting input terminal of the comparator CP2. Therefore, the signal level of the output terminal of the comparator CP2 becomes the L level. On the other hand, even when the supply of power to the power supply PS is interrupted, the inverting input terminal of the comparator CP2 is supplied with a voltage obtained by dividing the voltage of the Zener diode ZD2 by the resistor elements R10 and R11. However, in this case, when the voltage divided by resistor elements R8 and R9 exceeds the reference voltage of the inverting input terminal of the non-inverting input terminal of comparator CP2, the output of comparator CP2 is inverted from L level to H level. As a result, the signal level of the output terminal of comparator CP2 becomes an H level signal.

Here, as described above, the delay circuit unit CT4 includes the capacitor C3. Therefore, when the supply of power to the power supply device PS is interrupted, the delay circuit unit CT4 can delay the time when the signal level of the output terminal of the comparator CP1 becomes H level and the output of the delay circuit unit CT4 becomes high impedance by a time corresponding to the capacitance of the capacitor C3. In other words, the delay circuit unit CT4 can delay the time required for the state of the phototransistor PT of the switch circuit unit CT5 to switch from the ON state (L level) to the OFF state (H level) in that case. This allows the auxiliary power supply device 1 to suppress, for example, the detection of a momentary interruption in the input of the power supply device PS.

<Circuit configuration of switch circuit section>
The circuit configuration of the switch circuit section CT5 will be described below.

The switch circuit section CT5 includes a switch element S2.

In the following, as an example, a case where the switch element S2 is a photocoupler will be described. Therefore, in FIG. 1, the switch element S2 includes a light-emitting diode D6 and the above-mentioned phototransistor PT. In addition, instead of a photocoupler, the switch element S2 may be another switch element such as a field effect transistor, a bipolar transistor, or a relay switch. In this case, these switch elements function in place of the phototransistor PT.

The input terminal CT51 of the switch circuit section CT5 is connected to the anode of the light-emitting diode D6 via a transmission line. The cathode of the light-emitting diode D6 is connected to the input terminal CT52 of the switch circuit section CT5. The base terminal of the phototransistor PT receives the light emitted from the light-emitting diode D6. The collector terminal of the phototransistor PT is connected to one of the two terminals of the resistor element R13 via a transmission line. The other of the two terminals of the resistor element R13 is connected to the signal terminal CT53 of the switch circuit section CT5. The emitter terminal of the phototransistor PT is connected to the signal terminal CT54 of the switch circuit section CT5 via a transmission line. In addition, the switch circuit unit CT5 may be configured to include other circuit elements, other devices, etc. in addition to the switch element S2 and the resistance element R13, or in place of one or both of the switch element S2 and the resistance element R13, as long as the functions of the switch circuit unit CT5 described in this embodiment are not impaired.

<Operation of Switch Circuit>
The operation of the switch circuit section CT5 will now be described.

1, the signal terminals T3 and T4 of the auxiliary power supply device 1 are connected to the external device EX. As described above, the power supply circuit with a display function provided in the external device EX is connected to the signal terminals T3 and T4 of the auxiliary power supply device 1. A voltage is applied between the signal terminals T3 and T4 of the auxiliary power supply device 1 from the external device EX. That is, a voltage is applied between the signal terminals T3 and T4 by the power supply circuit. When the power supply to the power supply device PS is not cut off, the phototransistor PT is in the on state, so that the signal terminals T3 and T4 are electrically connected in the switch circuit section CT5, and the voltage level between the signal terminals T3 and T4 becomes the L level. In this case, the display function causes the light-emitting diode EX2 to emit light, indicating that power is being supplied to the power supply device PS. On the other hand, when the power supply to the power supply PS is cut off, the signal level of the output terminal of the delay circuit section CT4 becomes H level, and the light-emitting diode D6 does not emit light. As a result, the state of the phototransistor PT becomes the OFF state, the signal terminal T3 and the signal terminal T4 in the switch circuit section CT5 are electrically disconnected, and the voltage level between the signal terminal T3 and the signal terminal T4 becomes H level. In this case, the display function turns off the light-emitting diode EX2 to notify that the power supply to the power supply PS has been cut off.

As described above, the auxiliary power supply device 1 switches the state of the switch element (in this example, the phototransistor PT) of the switch circuit section CT5 from the on state to the off state in response to the discharge current discharged from the capacitor C1. This allows the auxiliary power supply device 1 to maintain the output from the power supply device for a predetermined period of time when the supply of power to the power supply device PS is interrupted, and can more reliably notify the power supply device PS that the supply of power to the power supply device PS has been interrupted at the desired timing.

<First Modification of the Embodiment>
The following describes the first modified example of the embodiment.

In the first modified embodiment, the diode D2 of the constant voltage circuit unit CT2 may be configured as a light-emitting diode. In this case, the diode D2 lights up when the voltage of the capacitor C1 is equal to or higher than a predetermined threshold, and turns off when the voltage of the capacitor C1 is less than the threshold. Thus, the diode D2 functions as a display unit that displays information indicating that the voltage of the capacitor C1 is equal to or higher than the threshold when the voltage of the capacitor C1 is equal to or higher than a predetermined threshold, and displays information indicating that the voltage of the capacitor C1 is less than the threshold when the diode D2 turns off when the voltage of the capacitor C1 is less than the threshold. This allows the auxiliary power supply device 1 to prevent a person from touching the auxiliary power supply device 1 when the voltage of the capacitor C1 is high.

In addition, instead of the diode D2 as a light-emitting diode, the auxiliary power supply device 1 may be configured to include, as the above-mentioned display unit, a display or the like that displays information indicating that the voltage of capacitor C1 is equal to or greater than a predetermined threshold value when the voltage of capacitor C1 is equal to or greater than the threshold value, and that displays information indicating that the voltage of capacitor C1 is less than the threshold value when the voltage of capacitor C1 is less than the threshold value.

<Modification 2 of the embodiment>
The second modification of the embodiment will be described below.

In the second modification of the embodiment, the auxiliary power supply device 1 may be configured to include a constant voltage circuit unit CT2A instead of the constant voltage circuit unit CT2.

Figure 2 is a diagram showing an example of the configuration of the auxiliary power supply device 1 according to the second modification of the embodiment.

As shown in FIG. 2, the constant voltage circuit unit CT2A has four terminals, input terminal CT21, input terminal CT22, output terminal CT23, and output terminal CT24, just like the constant voltage circuit unit CT2. The constant voltage circuit unit CT2A also includes a capacitor C2, a resistor element R2, a resistor element R3, a resistor element R4, a diode D2, a switch element S1, a Zener diode ZD1, a shunt regulator SHR, a resistor element R14, and a resistor element R15.

The input terminal CT21 of the constant voltage circuit unit CT2A is connected to one of the two terminals of the resistor element R2 and one of the two terminals of the resistor element R3 via a transmission line. The other of the two terminals of the resistor element R2 is connected to the cathode of the Zener diode ZD1 and the gate terminal of the switch element S1 via a transmission line. The anode of the Zener diode ZD1 is connected to one of the two terminals of the resistor element R4, the cathode terminal of the shunt regulator SHR, the output terminal CT23 of the constant voltage circuit unit CT2, and one of the two terminals of the capacitor C2 via a transmission line. The other of the two terminals of the resistor element R4 is connected to the source terminal of the switch element S1 via a transmission line. The drain terminal of the switch element S1 is connected to the cathode of the diode D2 via a transmission line. The anode of the diode D2 is connected to the other of the two terminals of the resistor element R3 via a transmission line. The anode terminal of the shunt regulator SHR and the other of the two terminals of the capacitor C2 are connected to the input terminal CT22 of the constant voltage circuit unit CT2, the output terminal CT24 of the constant voltage circuit unit CT2, and one of the two terminals of the resistor element R15 via a transmission line. The cathode terminal of the shunt regulator SHR is also connected to one of the two terminals of the resistor element R14. The other of the two terminals of the resistor element R14 is connected to the reference terminal of the shunt regulator SHR and the other of the two terminals of the resistor element R15. In addition, the constant voltage circuit unit CT2A may be configured to include other circuit elements, other devices, etc. in addition to the capacitor C2, the resistor element R2, the resistor element R3, the resistor element R4, the diode D2, the switch element S1, the Zener diode ZD1, the shunt regulator SHR, the resistor element R14, and the resistor element R15, or in place of some or all of the capacitor C2, the resistor element R2, the resistor element R3, the resistor element R4, the diode D2, the switch element S1, the Zener diode ZD1, the shunt regulator SHR, the resistor element R14, and the resistor element R15, as long as the functions of the constant voltage circuit unit CT2A described in this embodiment are not impaired.

The constant voltage circuit unit CT2A flows a constant current of a predetermined magnitude according to the voltage applied from the smoothing capacitor SC of the power supply device PS or the voltage applied from the capacitor C1. The voltage of the output terminal CT23 is made constant by the shunt regulator SHR and the resistor elements R14 and R15. As a result, the voltage of the output terminal CT23 is further stabilized by the capacitor C2. The magnitude of the current of the constant voltage circuit unit CT2A is determined by the voltage generated in the resistor element R4 (the voltage obtained by subtracting the gate-source voltage of the switch element S1 from the Zener voltage of the Zener diode ZD1). The output voltage of the constant voltage circuit unit CT2 is used to drive the discharge current detection circuit unit CT3, and is also used by the delay circuit unit CT4 and the switch circuit unit CT5, which will be described later. The voltage output from the constant voltage circuit unit CT2A is the voltage used to generate the reference voltage of the comparator CP1 of the discharge current detection circuit unit CT3. Therefore, the discharge current detection circuit CT3 can detect the discharge current discharged from the capacitor C1 even if the auxiliary power supply device 1 has a constant voltage circuit CT2A instead of the constant voltage circuit CT2. As a result, even if the auxiliary power supply device 1 has a constant voltage circuit CT2A instead of the constant voltage circuit CT2, when the supply of power to the power supply device PS is interrupted, the output from the power supply device PS can be maintained for a predetermined time, and the fact that the supply of power to the power supply device PS has been interrupted can be notified more reliably at the desired timing.

<Modification 3 of the embodiment>
The third modified example of the embodiment will be described below.

In the third modified embodiment, the auxiliary power supply device 1 may be configured to include a capacitor C4.

Figure 3 is a diagram showing an example of the configuration of the auxiliary power supply device 1 according to the third modification of the embodiment.

As shown in FIG. 3, the auxiliary power supply device 1 according to the third embodiment further includes a capacitor C4 that is connected in parallel with the charge/discharge circuit section CT1 between the power supply terminal T1 and the power supply terminal T2 and is located in a stage preceding the charge/discharge circuit section CT1.

When the auxiliary power supply device 1 is connected to the power supply device PS, the capacitor C4, together with the smoothing capacitor SC of the power supply device PS, smooths the voltage after rectification on the primary side of the power supply device PS. In other words, the auxiliary power supply device 1 shown in FIG. 3 can also assist in smoothing the voltage on the primary side of the power supply device PS.

In addition, power supplies PS tend to be smaller, and there are often no space to provide a terminal for connecting the auxiliary power supply device 1. In such cases, the smoothing capacitor SC can be removed from the power supply device PS and the terminal can be provided. However, this would cause the power supply device PS to stop working. In such cases, the auxiliary power supply device 1 shown in FIG. 3 can achieve both the miniaturization of the power supply device PS and the installation of the auxiliary power supply device 1, since the capacitor C4 acts as a substitute for the smoothing capacitor SC. In such cases, the auxiliary power supply device 1 may be configured integrally with the power supply device PS, or may be configured separately from the power supply device PS.

<Specific examples of power supply devices to which the auxiliary power supply device can be connected>
A specific example of the power supply device PS to which the above-mentioned auxiliary power supply device 1 is connected will be described below.

Figure 4 is a diagram showing an example of the configuration of a power supply device PS to which the auxiliary power supply device 1 is connected. The power supply device PS shown in Figure 4 is a power supply device to which a medical device MD is connected as a load. The medical device MD is a medical device that operates based on the DC voltage Vo output by the power supply device PS, and is, for example, a treatment device, a diagnostic device, an analytical device, etc., but is not limited to these. Note that treatment devices are, for example, low-frequency treatment devices, electric treatment devices, etc. Furthermore, diagnostic devices are, for example, CT (Computed Tomography), MRI (Magnetic Resonance Imaging), etc. Analytical devices are, for example, electric titration devices, X-ray diffraction devices, etc.

The power supply device PS has seven terminals, namely, power supply terminal PS1, power supply terminal PS2, frame ground terminal PS3, output terminal PS4, output terminal PS5, connection terminal PS6, and connection terminal PS7. For example, a commercial power supply is connected to power supply terminal PS1 and power supply terminal PS2, and an AC voltage Vx is supplied from the commercial power supply. For example, the frame ground terminal PS3 is grounded to ground. For example, the power supply terminal of the medical device MD is connected to output terminal PS4 and output terminal PS5. That is, the power supply device PS supplies a DC voltage Vo to the power supply terminal of the medical device MD from output terminal PS4 and output terminal PS5. For example, the auxiliary power supply device 1 is connected to connection terminal PS6 and connection terminal PS7. More specifically, the power supply terminal T1 of the auxiliary power supply device 1 is connected to connection terminal PS6. On the other hand, the power supply terminal T2 of the auxiliary power supply device 1 is connected to connection terminal PS7.

The power supply device PS shown in FIG. 4 includes, for example, a fuse section HS, a rectifier/smoothing circuit section RS, a switching circuit section SW, a transformer TR, a rectifier circuit section RF, and a smoothing circuit section SM. The power supply device PS also includes an input transmission line L connected to the power supply terminal PS1, and an input transmission line N connected to the power supply terminal PS2.

The fuse section HS is provided in the power supply PS so that the power supply PS meets the medical standards that the power supply PS must meet as a power supply connected to the medical device MD. The fuse section HS has a fuse provided on the input transmission line L that connects between the power supply terminal PS1 and the rectifying and smoothing circuit section RS, and a fuse provided on the input transmission line N that connects between the power supply terminal PS2 and the rectifying and smoothing circuit section RS. The power supply PS may be configured to include a breaker in place of either or both of these two fuses.

The rectifying and smoothing circuit unit RS generates a pulsating voltage by rectifying the AC voltage Vx supplied from two transmission paths, an input transmission path L connected to the power supply terminal PS1 via the fuse part HS and an input transmission path N connected to the power supply terminal PS2 via the fuse part HS, and smooths the generated pulsating voltage to output a DC voltage Vin. For this reason, the rectifying and smoothing circuit unit RS is provided with a smoothing capacitor SC that supplies a voltage for smoothing the pulsating voltage after rectification. Here, one of the two terminals of the smoothing capacitor SC is connected to the input transmission path L. The other of the two terminals of the smoothing capacitor SC is connected to the input transmission path N. However, in FIG. 4, in order to prevent the diagram from becoming complicated, the transmission paths connecting the smoothing capacitor SC to each of the input transmission path L and the input transmission path N are omitted. In this way, the rectifying and smoothing circuit unit RS is connected to the fuse part HS provided in the front stage of the rectifying and smoothing circuit unit RS via the input transmission path L and the input transmission path N. The rectifier smoothing circuit unit RS is connected to a connection terminal PS6 provided downstream of the rectifier smoothing circuit unit RS via an input transmission line L. The rectifier smoothing circuit unit RS is connected to a connection terminal PS7 provided downstream of the rectifier smoothing circuit unit RS via an input transmission line N. Therefore, the rectifier smoothing circuit unit RS applies the smoothed DC voltage Vin between the connection terminals PS6 and PS7. The rectifier smoothing circuit unit RS may further include a power factor correction circuit (PFC (Power Factor Correction) circuit).

The connection terminal PS6 is connected to one of the two input terminals of the switching circuit unit SW via the input transmission path L. The connection terminal PS7 is connected to the other of the two input terminals of the switching circuit unit SW via the input transmission path L. Therefore, the DC voltage Vin output from the rectifying and smoothing circuit unit RS is supplied to the switching circuit unit SW. The switching circuit unit SW includes, for example, a plurality of switch elements connected in a bridge configuration, and outputs an AC voltage generated by the operation of these plurality of switch elements controlled by the control unit CTR based on the DC voltage supplied from the rectifying and smoothing circuit unit RS to the primary winding of the transformer TR. Therefore, the switching circuit unit SW is connected to one of the two terminals of the winding via the input transmission path L, and is connected to the other of the two terminals of the winding via the input transmission path N.

The transformer TR is a transformer with reinforced insulation. The reason that the transformer TR has reinforced insulation is so that the power supply PS meets the medical standards mentioned above. The secondary winding of the transformer TR is connected to the rectifier circuit section RF via a transmission line, and supplies AC voltage to the rectifier circuit section RF.

The rectifier circuit section RF rectifies the AC voltage supplied from the transformer TR to generate a pulsating voltage, and supplies the generated pulsating voltage to the smoothing circuit section SM via a transmission path.

The smoothing circuit section SM smoothes the pulsating voltage supplied from the rectifier circuit section RF to generate a DC voltage, and applies the generated DC voltage Vo between the output terminals PS4 and PS5.

The current detection circuit DC detects the current flowing through the input transmission path N that connects the connection terminal PS7 and the switching circuit SW. The current detection circuit DC then outputs a signal corresponding to the magnitude of the detected current to the control unit CTR.

The control unit CTR is, for example, a microcomputer. The control unit CTR controls the duty at the drive frequency of the switching circuit unit SW (for example, PWM control: Pulse Width Modulation Control) in response to the signal acquired from the current detection circuit unit DC, and switches the switch element. Note that in FIG. 4, the transmission path connecting the control unit CTR and the switching circuit unit SW is omitted to avoid cluttering the diagram.

In this way, the power supply device PS to which the medical device MD is connected as a load has a fuse (or breaker) in the fuse section HS in each of the input transmission line L and the input transmission line N. The auxiliary power supply device 1 according to each of the embodiment, the modified example 1 of the embodiment, the modified example 2 of the embodiment, and the modified example 3 of the embodiment is connected to such a power supply device PS, for example. In this case, the auxiliary power supply device 1, the power supply device PS, and the medical device MD each constitute one medical system. This medical system can realize a configuration that can obtain medical standards because the power supply device PS has a fuse section HS and the transformer TR has reinforced insulation. And because this medical system includes the auxiliary power supply device 1, when the supply of power to the power supply device PS is interrupted, the output from the power supply device PS can be maintained for a predetermined time, and the interruption of the supply of power to the power supply device PS can be more reliably notified at the desired timing.

Moreover, many medical devices MD have a function of charging the DC voltage Vo to a secondary battery for backup. For this reason, the power supply unit PS may be capable of detecting the occurrence of reverse current from the medical device MD, and may be configured to stop operation when the occurrence of reverse current from the medical device MD is detected.

Here, the power supply device PS shown in FIG. 4 has an internal fuse section HS. However, the power supply device PS may have an external fuse section HS as shown in FIG. 5. That is, the fuse section HS may be separate from the power supply device PS and connected between the power supply device PS and a commercial power source (not shown). In this case, the medical system includes an auxiliary power supply device 1, a power supply device PS, a medical device MD, and a fuse section HS. FIG. 5 is a diagram showing another example of the configuration of the power supply device PS to which the auxiliary power supply device 1 is connected.

As shown in FIG. 5, when the fuse section HS is provided outside the power supply PS, one of the two fuses in the fuse section HS is provided on the transmission path connecting a commercial power source (not shown) and the power supply terminal PS1. When the fuse section HS is provided outside the power supply PS, the other of the two fuses in the fuse section HS is provided on the transmission path connecting a commercial power source (not shown) and the power supply terminal PS2.

The power supply PS may also be configured to have one of the two fuses in the fuse section HS internally and the other of the two fuses in the fuse section HS externally, as shown in FIG. 6. FIG. 6 is a diagram showing yet another example of the configuration of the power supply PS to which the auxiliary power supply device 1 is connected.

As shown in FIG. 6, the power supply device PS may be configured such that a first fuse section HS1 is provided on a transmission path connecting a commercial power source (not shown) and a power supply terminal PS1, and a second fuse section HS2 is provided on an input transmission path N connecting a power supply terminal PS2 and a rectifying and smoothing circuit section RS.

Here, the first fuse section HS1 includes a fuse provided on a transmission line connecting a commercial power source (not shown) and the power supply terminal PS1. The second fuse section HS2 includes a fuse provided on an input transmission line N connecting the power supply terminal PS2 and the rectifying and smoothing circuit section RS.

<Fourth Modification of the Embodiment>
The fourth modified example of the embodiment will be described below.

In a fourth modified embodiment, the auxiliary power supply device 1 may be configured to switch the state of the phototransistor PT to the on state when the supply of power to the power supply device PS is interrupted.

Figure 7 is a diagram showing an example of the configuration of an auxiliary power supply device 1 according to the fourth modification of the embodiment.

As shown in FIG. 7, in the auxiliary power supply device 1 according to the fourth modified embodiment, the resistor elements R7, R8, R9, and capacitor C3 of the delay circuit unit CT4 are connected to the inverting input terminal of the comparator CP2 via a transmission line, instead of being connected to the non-inverting input terminal of the comparator CP2. In this case, the resistor elements R10 and R11 of the delay circuit unit CT4 are connected to the non-inverting input terminal of the comparator CP2, instead of being connected to the inverting input terminal of the comparator CP2. As a result, when power is supplied to the power supply device PS, the signal level of the output terminal of the comparator CP2 becomes H level. As a result, the state of the phototransistor PT becomes OFF in this case. On the other hand, when the supply of power to the power supply device PS is cut off, the output of the comparator CP2 is inverted from H level to L level. As a result, the state of the phototransistor PT becomes ON in this case.

Therefore, the external device EX connected to the auxiliary power supply device 1 according to the fourth modified embodiment turns off the light-emitting diode EX2 when power is being supplied to the power supply device PS. On the other hand, when the supply of power to the power supply device PS is interrupted, the external device EX causes the light-emitting diode EX2 to emit light, thereby notifying the power supply device PS that the power supply has been interrupted. In this way, even if the auxiliary power supply device 1 is configured to switch the state of the phototransistor PT to the on state when the supply of power to the power supply device PS is interrupted, the output from the power supply device PS can be maintained for a predetermined time when the supply of power to the power supply device PS is interrupted, and the fact that the supply of power to the power supply device PS has been interrupted can be more reliably notified at the desired timing.

<Fifth Modification of the Embodiment>
The fifth modified example of the embodiment will be described below.

Figure 8 is a diagram showing an example of the configuration of an auxiliary power supply device 1 according to the fifth embodiment.

As shown in FIG. 8, in the external device EX according to the fifth modified embodiment, one of the two terminals of the resistor element EX1 and the anode of the light-emitting diode EX2 are connected to the signal terminal T3 via a transmission line. The other of the two terminals of the resistor element EX1 are connected to the positive terminal of the DC voltage source EX3 via a transmission line. The cathode of the light-emitting diode EX2 is connected to the negative terminal of the DC voltage source EX3 and the signal terminal T4 via a transmission line. That is, in the external device EX, the light-emitting diode EX2 and the combination of the resistor element EX1 and the DC voltage source EX3 are connected in parallel between the signal terminals T3 and T4.

Therefore, the external device EX connected to the auxiliary power supply device 1 according to the fifth modified embodiment turns off the light-emitting diode EX2 when power is being supplied to the power supply device PS. On the other hand, when the supply of power to the power supply device PS is cut off, the external device EX causes the light-emitting diode EX2 to light up, thereby notifying that the supply of power to the power supply device PS has been cut off. In this way, when the supply of power to the power supply device PS is cut off, the auxiliary power supply device 1 can maintain the output from the power supply device PS for a predetermined period of time, and can more reliably notify at the desired timing that the supply of power to the power supply device PS has been cut off.

When the fifth embodiment and the fourth embodiment are combined, the external device EX connected to the auxiliary power supply device 1 causes the light-emitting diode EX2 to emit light when power is being supplied to the power supply device PS. In this case, the external device EX turns off the light-emitting diode EX2 when the power supply to the power supply device PS is cut off. Even in this case, the auxiliary power supply device 1 can maintain the output from the power supply device PS for a predetermined time when the power supply to the power supply device PS is cut off, and can more reliably notify at a desired timing that the power supply to the power supply device PS has been cut off.

<Sixth Modification of the Embodiment>
The sixth modified example of the embodiment will be described below.

The auxiliary power supply device 1 according to the sixth modified embodiment may be configured to output a first signal indicating that the supply of power to the power supply device PS has been cut off when the phototransistor PT is in the off state. In this case, the external device EX does not have a power supply circuit as described above, and when it acquires the first signal, it notifies the external device EX by light, sound, vibration, etc., in response to the acquired first signal that the supply of power to the power supply device PS has been cut off.

Figure 9 is a diagram showing an example of the configuration of the auxiliary power supply device 1 according to the sixth modification of the embodiment.

9, in the auxiliary power supply device 1 according to the sixth modified embodiment, one of the two terminals of the resistor element R16 is connected to the transmission path connecting the collector terminal of the phototransistor PT of the switch circuit section CT5 and the signal terminal T3 via another transmission path. The other of the two terminals of the resistor element R16 is connected to the positive terminal of the internal voltage source P1 via the transmission path. The internal voltage source P1 is, for example, a battery, but may be another DC voltage source. The negative terminal of the internal voltage source P1 is connected to the terminal T5 via the transmission path. The circuit to which the terminal T5 is connected via the transmission path may be any circuit. For this reason, in FIG. 9, the circuit to which the terminal T5 is connected via the transmission path is omitted. However, the voltage of the terminal T5 is set to the same potential as the potential of the signal terminal T4 by a predetermined method. The predetermined method may be any method that can set the potential of the terminal T5 to the same potential as the potential of the signal terminal T4. In FIG. 9, the potential of signal terminal T4 and the potential of terminal T5 are each indicated by potential VT4.

With the above-described configuration, the auxiliary power supply device 1 according to the sixth modified embodiment can output a first signal indicating that the power supply to the power supply device PS has been cut off when the phototransistor PT is in the off state. This allows the auxiliary power supply device 1 to hold the output from the power supply device PS for a predetermined time when the power supply to the power supply device PS is cut off, and can notify the user at a desired timing by outputting the first signal that the power supply to the power supply device PS has been cut off.

The embodiments and variations of the embodiments described above may be combined in any manner.

As described above, the auxiliary power supply device according to the embodiment (in the example described above, auxiliary power supply device 1) is an auxiliary power supply device connected to both terminals of a smoothing capacitor of a power supply device (in the example described above, power supply device PS) that has a primary-side smoothing capacitor (in the example described above, smoothing capacitor SC), and is equipped with a first power supply terminal (in the example described above, power supply terminal T1) connected to a first smoothing capacitor terminal of the smoothing capacitor, a second power supply terminal (in the example described above, power supply terminal T2) connected to a second smoothing capacitor terminal of the smoothing capacitor, a first capacitor (in the example described above, capacitor C1) that is connected between the first power supply terminal and the second power supply terminal and is charged when power is supplied to the power supply device and discharges a discharge current in response to the discharge of the smoothing capacitor, and a switch circuit unit (in the example described above, switch circuit unit CT5) having a switch element that switches its state between an on state and an off state in response to the discharge current discharged from the first capacitor. This allows the auxiliary power supply device to maintain output from the power supply device for a specified period of time when the power supply to the power supply device is cut off, and to more reliably notify the power supply device that the power supply has been cut off at the desired timing.

In addition, in the auxiliary power supply device, the switch circuit section may have two connection terminals (signal terminals T3 and T4 in the example described above) to which an external device can be connected, and the switch element may be configured to electrically connect the two connection terminals in the switch circuit section when in the on state, and electrically disconnect the two connection terminals in the switch circuit section when in the off state.

The auxiliary power supply device may also be configured such that the switch circuitry outputs a first signal indicating that the supply of power to the power supply device has been cut off when the switch element is in an on or off state.

In addition, in the auxiliary power supply device, the first capacitor may be configured to discharge a discharge current in response to the discharge of the smoothing capacitor when the first smoothing capacitor terminal is connected to the first power supply terminal and the second smoothing capacitor terminal is connected to the second power supply terminal.

The auxiliary power supply device also includes a charge/discharge circuit unit (in the example described above, charge/discharge circuit unit CT1) having a first capacitor, a constant voltage circuit unit (in the example described above, constant voltage circuit unit CT2, constant voltage circuit unit CT2A) that outputs a voltage of a predetermined magnitude, and a discharge current detection circuit unit (in the example described above, discharge current detection circuit unit CT3) that detects that a discharge current has been discharged from the first capacitor based on the voltage output from the constant voltage circuit unit, and the charge/discharge circuit unit is connected to an eleventh capacitor of the two terminals of the first capacitor. The circuit may further include a first resistor element (resistor element R1 in the example described above) connected between the 11th capacitor terminal and the second power supply terminal, and a diode (diode D1 in the example described above) connected in parallel with the first resistor element between the 11th capacitor terminal and the second power supply terminal, the direction in which the diode passes current is from the second power supply terminal to the first capacitor, and the switch element switches its state to an on state or an off state when the discharge current detection circuit detects a discharge current discharged from the first capacitor.

In addition, in the auxiliary power supply device, the constant voltage circuit section may be configured to include a Zener diode (Zener diode ZD2 in the example described above) and a constant voltage generating capacitor (capacitor C2 in the example described above) connected in parallel with the Zener diode.

In addition, in the auxiliary power supply device, the constant voltage circuit unit may be configured to include a shunt regulator (in the example described above, shunt regulator SHR), two resistive elements connected to the shunt regulator (in the example described above, resistive elements R14 and R15), and a constant voltage generating capacitor connected in parallel to the shunt regulator.

The auxiliary power supply device may also be configured to include one or more second resistor elements (resistor elements R8 to R12 in the example described above) and one or more second capacitors (capacitor C3 in the example described above), and further include a delay circuit section (delay circuit section CT4 in the example described above) that delays the time required for the switch element in the switch circuit section to switch its state to the on state or the off state when the discharge current discharged from the first capacitor is detected by the discharge current detection circuit section.

The auxiliary power supply device may also be configured to further include a third capacitor (capacitor C4 in the example described above) connected between the first power supply terminal and the second power supply terminal and located in a stage preceding the charge/discharge circuit unit.

The auxiliary power supply device may also be configured to include a display unit (in the example described above, the diode D2 as a light-emitting diode) that displays information indicating that the voltage of the first capacitor is equal to or greater than a predetermined threshold value when the voltage of the first capacitor is equal to or greater than the threshold value, and that displays information indicating that the voltage of the first capacitor is less than the threshold value when the voltage of the first capacitor is less than the threshold value.

The power supply device according to the embodiment is a power supply device that includes the auxiliary power supply device described above. This allows the power supply device to maintain output from the power supply device for a predetermined period of time when the supply of power to the power supply device is interrupted, and to more reliably notify the user at a desired timing that the supply of power to the power supply device has been interrupted.

The power supply device according to the embodiment includes a smoothing capacitor on the primary side, a first power supply terminal connected to a first smoothing capacitor terminal of the smoothing capacitor, a second power supply terminal connected to a second smoothing capacitor terminal of the smoothing capacitor, a first capacitor connected between the first power supply terminal and the second power supply terminal, charged by power being supplied to the power supply device, and discharging a discharge current in response to the discharge of the smoothing capacitor, and a switch circuit unit having a switch element that switches between an on state and an off state in response to the discharge current discharged from the first capacitor. This allows the power supply device to hold the output from the power supply device for a predetermined time when the supply of power to the power supply device is interrupted, and to more reliably notify the power supply device that the supply of power to the power supply device has been interrupted at a desired timing.

The medical system according to the embodiment includes the auxiliary power supply device described above, a power supply device, and a medical device (medical device MD in the example described above) connected to the power supply device as a load. This allows the medical system to maintain the output from the power supply device for a predetermined period of time when the power supply to the power supply device is cut off, and to more reliably notify the user at a desired timing that the power supply to the power supply device has been cut off.

In addition, in a medical system, the power supply device may be configured to include a fuse or breaker provided in at least one of the two input transmission paths on the primary side of the power supply device.

The embodiment of the present invention has been described above in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and may be changed, replaced, deleted, etc., without departing from the spirit of the present invention.

1...Auxiliary power supply device, C1, C2, C3, C4...Capacitor, CP1, CP2...Comparator, CT1...Charge/discharge circuit section, CT2, CT2A...Constant voltage circuit section, CT3...Discharge current detection circuit section, CT4...Delay circuit section, CT5...Switch circuit section, CTR...Control section, D1, D2, D3, D4, D5...Diode, D6...Light-emitting diode, DC...Current detection circuit section, EX...External device, EX1...Resistance element, EX2...Light-emitting diode, EX3...DC voltage source, HS...Fuse section, HS1...First fuse section, HS2...Second fuse section, L...Input transmission path, MD ...medical device, N...input transmission path, P1...internal voltage source, PS...power supply, PT...phototransistor, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R14, R15, R16...resistance element, RF...rectifier circuit section, RS...rectifier smoothing circuit section, S1, S2...switching element, SC...smoothing capacitor, SM...smoothing circuit section, SW...switching circuit section, T1...power supply terminal, T2...power supply terminal, T3...signal terminal, T4...signal terminal, T5...terminal, TR...transformer, ZD1...zener diode, ZD2...zener diode

Claims (14)

1. An auxiliary power supply device connected to both terminals of a smoothing capacitor of a power supply device having a smoothing capacitor on a primary side,
a first power supply terminal connected to a first smoothing capacitor terminal of the smoothing capacitor;
a second power supply terminal connected to a second smoothing capacitor terminal of the smoothing capacitor;
a first capacitor connected between the first power supply terminal and the second power supply terminal, charged when power is supplied to the power supply device, and discharging a discharge current in response to discharging of the smoothing capacitor;
a switch circuit section having a switch element that switches between an on state and an off state in response to a discharge current discharged from the first capacitor;
An auxiliary power supply device comprising: the switch circuit unit has two connection terminals to which an external device can be connected;
When the switch element is in an on state, it electrically connects the two connection terminals in the switch circuit unit, and when the switch element is in an off state, it electrically disconnects the two connection terminals in the switch circuit unit.
2. The auxiliary power supply of claim 1. the switch circuit outputs a first signal indicating that the supply of power to the power supply device has been cut off when the switch element is in an on state or an off state.
3. An auxiliary power supply device according to claim 1 or 2. the first capacitor discharges a discharge current in response to discharging of the smoothing capacitor when the first smoothing capacitor terminal is connected to the first power supply terminal and the second smoothing capacitor terminal is connected to the second power supply terminal;
An auxiliary power supply device according to any one of claims 1 to 3. a charge/discharge circuit unit including the first capacitor;
A constant voltage circuit unit that outputs a voltage of a predetermined magnitude;
a discharge current detection circuit that detects that a discharge current has been discharged from the first capacitor based on a voltage output from the constant voltage circuit;
Equipped with
The charge/discharge circuit unit includes:
a first resistor element connected between an eleventh capacitor terminal of the first capacitor and the second power supply terminal;
a diode connected in parallel with the first resistor element between the eleventh capacitor terminal and the second power supply terminal;
Further comprising:
a direction in which the diode passes a current is a direction from the second power supply terminal to the first capacitor,
the switch element switches its state between an on state and an off state when a discharge current discharged from the first capacitor is detected by the discharge current detection circuit unit.
An auxiliary power supply device according to any one of claims 1 to 4. The constant voltage circuit unit includes a Zener diode and a constant voltage generating capacitor connected in parallel with the Zener diode.
6. An auxiliary power supply as claimed in claim 5. the constant voltage circuit unit includes a shunt regulator, two resistance elements connected to the shunt regulator, and a constant voltage generating capacitor connected in parallel to the shunt regulator;
6. An auxiliary power supply as claimed in claim 5. the switch circuit further comprises a delay circuit section which delays a time required for the switch element to switch a state to an ON state or an OFF state when a discharge current discharged from the first capacitor is detected by the discharge current detection circuit section;
An auxiliary power supply device according to any one of claims 5 to 7. a third capacitor connected between the first power supply terminal and the second power supply terminal and located in a stage preceding the charge/discharge circuit unit,
An auxiliary power supply according to any one of claims 5 to 8. a display unit that, when the voltage of the first capacitor is equal to or greater than a predetermined threshold, displays information indicating that the voltage of the first capacitor is equal to or greater than the threshold, and, when the voltage of the first capacitor is less than the threshold, displays information indicating that the voltage of the first capacitor is less than the threshold.
10. An auxiliary power supply according to any one of claims 1 to 9. The power supply device comprises an auxiliary power supply device according to any one of claims 1 to 10,
Power supply. 1. A power supply device, comprising:
A smoothing capacitor on the primary side;
a first power supply terminal connected to a first smoothing capacitor terminal of the smoothing capacitor;
a second power supply terminal connected to a second smoothing capacitor terminal of the smoothing capacitor;
a first capacitor connected between the first power supply terminal and the second power supply terminal, charged when power is supplied to the power supply device, and discharging a discharge current in response to discharging of the smoothing capacitor;
a switch circuit section having a switch element that switches between an on state and an off state in response to a discharge current discharged from the first capacitor;
A power supply device comprising: An auxiliary power supply device according to any one of claims 1 to 10;
The power supply device;
A medical device connected as a load to the power supply;
A medical system that has: The power supply device includes a fuse or a breaker provided in at least one of two input transmission paths on the primary side of the power supply device.
The medical system of claim 13.

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