JP6209612B2 - Power supply device and telephone system - Google Patents

Description

  The present invention relates to a power supply device and a telephone system, and more particularly to a power supply device and a telephone system that generate a DC power supply from an AC power supply.

  Many of the components that make up electrical equipment operate on the basis of a DC power supply. Therefore, the electrical device has a power supply circuit or an AC adapter that generates a DC power from an AC power supplied from a commercial power supply or the like. However, the DC power generated by the power supply circuit may vary in voltage level due to fluctuations in the AC power, and there is a risk that a device that operates with the DC power supply may malfunction. In view of this, Patent Documents 1 and 2 disclose techniques for monitoring AC power supplied from the outside.

  Patent Documents 1 and 2 disclose a technique for detecting a voltage drop or an instantaneous interruption of an AC power source and recording the date and time when the failure occurs.

JP 05-27495 A JP 05-324137 A

  However, it is difficult to determine what kind of power failure caused the malfunction of the system that operates with the DC power generated from the AC power even if the log of the voltage drop or instantaneous interruption of the AC power is acquired. There is a problem.

  One aspect of a power supply device according to the present invention includes a power supply control unit that outputs a PWM signal having a duty ratio according to a difference between a voltage of a DC system power supply and a preset target voltage, and a switching element based on the PWM signal. And a power supply circuit that outputs the DC system power supply from an AC power supply supplied from outside, and the power supply control unit has a noise level of the DC system power supply equal to or higher than a preset noise level threshold value. In response to this, a log indicating the status of the AC power supply is output.

  One aspect of a telephone system according to the present invention includes a power supply control unit that outputs a PWM signal having a duty ratio corresponding to a difference between a voltage of a DC system power supply and a preset target voltage, and a switching element based on the PWM signal. A power supply circuit that outputs the DC system power from an AC power supplied from the outside, and a private branch exchange that operates based on the DC system power and controls connection between the telephone terminal and the office line. The power supply control unit outputs a log indicating the status of the AC power supply in response to the noise level of the DC system power supply being equal to or higher than a preset noise level threshold.

  According to the power supply device and the telephone system according to the present invention, it can be determined whether or not the system failure is caused by the power supply failure.

1 is a block diagram of a telephone system according to a first exemplary embodiment. 1 is a block diagram of a power supply device according to a first exemplary embodiment. FIG. 3 is a diagram illustrating a first example of a log generated by the power supply device according to the first exemplary embodiment. FIG. 6 is a diagram illustrating a second example of a log generated by the power supply device according to the first embodiment. FIG. 6 is a diagram illustrating a third example of a log generated by the power supply device according to the first exemplary embodiment. FIG. 6 is a diagram illustrating a display example of a log generated by the power supply device according to the first embodiment; FIG. 3 is a block diagram of a power supply device according to a second exemplary embodiment. FIG. 6 is a block diagram of a power supply device according to a third exemplary embodiment. FIG. 6 is a block diagram of a power supply device according to a fourth exemplary embodiment.

Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings. The present invention relates to a power supply device. Although this power supply device is particularly effective when applied to a telephone system, the applicable system is not limited to a telephone system.

  FIG. 1 shows a block diagram of a telephone system 1 according to the first exemplary embodiment. As shown in FIG. 1, the telephone system 1 according to the first embodiment includes a power supply device 10, a private branch exchange 20, telephone terminals TM1 and TM2, and a system temperature sensor SEN. The system temperature sensor SEN outputs temperature information TSEN indicating the temperature inside the casing of the telephone system 1 (hereinafter referred to as ambient temperature).

  The power supply device 10 converts AC power supplied from an external commercial power supply into DC system power. In the following description, the voltage of the DC system power supply is expressed as DC output voltage VOUT. The power supply device 10 includes a power supply circuit 11, a power supply control unit 12, and an insulation circuit 13.

  The power supply circuit 11 switches the switching element based on the PWM signal generated by the power supply control unit 12 and outputs the DC system power supply from an AC power supply supplied from the outside. The power supply control unit 12 outputs a PWM signal having a duty ratio corresponding to the difference between the voltage of the DC system power supply (DC output voltage VOUT) and a preset target voltage. Moreover, the power supply control part 12 outputs the log which shows the condition of AC power supply, according to the noise level of DC system power supply becoming more than the preset noise level threshold value. This log is transmitted to the private branch exchange 20 or stored in a memory in the power supply control unit 12. For example, an MPU (Micro Processor Unit) that performs various calculations and controls according to a program is used as the power supply control unit 12. The insulation circuit 13 insulates the voltage observation point OVS and current observation point OCS of the power supply circuit 11 from the input terminal of the power supply control unit 12 and outputs a signal of a signal level corresponding to the voltage obtained from each observation point. Output. When the voltage observed at each observation point becomes larger than the input range of the power supply control unit 12, it is particularly effective to provide the insulation circuit 13. Details of the power supply device 10 will be described later.

  The private branch exchange 20 performs connection control between the telephone terminals TM1 and TM2 and the office line. The private branch exchange 20 operates based on a DC system power supply. The private branch exchange 20 includes a system control unit 21, a memory 22, a real-time clock generation unit 23, and an interface circuit 24.

  The system control unit 21 controls connection between the telephone terminal TM1 and the office line. For example, an MPU (Micro Processor Unit) that performs various calculations and controls according to a program is used as the system control unit 21. The memory 22 stores a program for operating the system control unit 21 and a log generated by the power supply device 10. The memory 22 is assumed to have a larger capacity than the memory provided in the power supply device 10. The real-time clock generator 23 generates a real-time clock signal to be given to the system controller 21. This real time clock signal is used for time measurement in the system control unit 21.

  The telephone terminals TM1 and TM2 are fixed telephones, for example. The telephone terminals TM1 and TM2 are connected to the interface circuit 24 of the private branch exchange 20. The telephone terminals TM1 and TM2 have a display unit (for example, LCD (Liquid Crystal Display)) and a terminal control unit for displaying various types of information such as incoming call information. As the terminal control unit, for example, an MPU (Micro Processor Unit) that performs various calculations and controls according to a program is used.

  Next, details of the power supply device 10 will be described. FIG. 2 shows a detailed block diagram of the power supply apparatus 10 according to the first embodiment. As shown in FIG. 2, the power supply circuit 11 of the power supply device 10 according to the second embodiment includes a rectifying / smoothing circuit 31, a driving circuit 32, a transformer 33, a rectifying / smoothing circuit 34, and a switching element (for example, driving transistor Tr) current detection. A resistor Rs1 and resistors R1 and R2 are provided.

  The rectifying / smoothing circuit 31 rectifies an AC input voltage supplied from an AC power source to generate a DC voltage. The drive circuit 32 generates a drive signal according to the PWM signal supplied from the power supply control unit 12 and switches the drive transistor Tr.

  The transformer 33 has a primary side coil and a secondary side coil. One end of the primary side coil is connected to the positive output terminal of the rectifying and smoothing circuit 31. The other end of the primary coil is connected to the negative output terminal of the rectifying / smoothing circuit 31 via the drive transistor Tr. The drive transistor Tr is an NMOS transistor. The drive transistor Tr has a gate supplied with a drive signal output from the drive circuit 32, a source connected to the negative output terminal of the rectifying and smoothing circuit 31, and a drain connected to the other end of the primary coil of the transformer 33.

  The secondary coil of the transformer 33 has one end connected to the positive input terminal of the rectifying / smoothing circuit 34 and the other end connected to the negative input terminal (for example, a ground node) of the rectifying / smoothing circuit 34. The rectifying / smoothing circuit 34 rectifies the pulse signal generated in the secondary coil of the transformer 33 and outputs a DC voltage. The DC voltage output from the rectifying / smoothing circuit 34 is a DC system power supply. The voltage of the DC system power supply is the DC output voltage VOUT of the power supply circuit 11.

  A power supply node is connected to the positive output terminal of the rectifying / smoothing circuit 34, and a ground node is connected to the negative output terminal of the rectifying / smoothing circuit 34. Resistors R1 and R2 are connected in series between the power supply node and the ground node. A node to which the resistor R1 and the resistor R2 are connected is a voltage observation point OVS. A current detection resistor Rs1 is inserted into the ground node. The terminal on the rectifying / smoothing circuit 34 side of the current detection resistor Rs1 is a current observation point OCS.

  The power supply control unit 12 includes an AD conversion circuit 41, a calculation unit 42, a PWM timer 43, a memory 44, and a real time clock generation unit 45.

  The AD conversion circuit 41 outputs a digital value corresponding to the voltage value of the current observation point OCS and the voltage value of the voltage observation point OVS obtained through the insulating circuit 13. Further, the power supply device 10 outputs a digital value corresponding to an AC input voltage value indicating a voltage level of the AC input voltage supplied from the AC power supply. Further, the AD conversion circuit 41 outputs a digital value corresponding to the temperature information TSEN output from the system temperature sensor SEN.

  The calculation unit 42 updates the set value of the PWM timer 43 so that the difference between the DC output voltage VOUT generated as the DC system power supply and the preset target voltage value approaches zero. The computing unit 42 performs processing such as Fourier transform and wavelet transform on the voltage value at the voltage observation point OVS, and further performs digital filter processing on the converted value. Thereby, the calculating part 42 observes at least 1 of C message noise of the voltage value of the voltage observation point OVS, sophometric noise, ripple noise, spike noise, and voltage fluctuation. The arithmetic unit 42 monitors the abnormal state of the DC output voltage VOUT of the power supply device 10 by monitoring the observed voltage value fluctuation, and when an abnormality is detected in the DC output voltage VOUT, the abnormality detection time point is detected. Output the log at. This log includes information such as the voltage value of the AC input voltage, the voltage value of the DC output voltage VOUT, the current value of the output current, the abnormality occurrence time, and the type of alarm. Details of this log will be described later. Note that the telephone system 1 according to the first embodiment outputs a periodic log in addition to the log at the time of detecting the abnormality of the DC output voltage VOUT.

  The PWM timer 43 outputs a PWM signal having a duty ratio corresponding to the set value given from the calculation unit 42. The PWM timer 43 determines the frequency of the PWM signal based on a system clock signal output from a system clock generator (not shown).

  The memory 44 stores a program for determining the operation of the calculation unit 42 and a log output by the calculation unit 42. The memory 44 stores various information such as intermediate data generated by the calculation unit 42 during the calculation.

  The real time clock generation unit 45 generates a real time clock signal. This real-time clock signal is used in the calculation unit 42 to acquire time. Note that the real-time clock signal generated by the real-time clock generator 23 of the private branch exchange 20 can be used as the real-time clock signal. In this case, the real-time clock generation unit 45 of the power supply control unit 12 is not necessary.

  Next, the operation of the telephone system 1 according to the first embodiment will be described. The telephone system 1 outputs a log including the state of the AC power supply when an abnormal state that is generated by the power supply device 10 and exceeds the assumed range of the DC output voltage VOUT used for the operation of the private branch exchange 20 occurs. Has one of the characteristics. Therefore, as an explanation of the operation of the telephone system 1, a log generated in the telephone system 1 will be described. There are various types of logs that can be generated by the power supply apparatus 10, but here, the logs will be described with three examples.

  FIG. 3 shows a first example of a log generated by the power supply device 10 according to the first exemplary embodiment. As shown in FIG. 3, in the first example, information such as an AC input voltage is acquired every 10 seconds. At this time, in the example shown in FIG. 3, the noise level of the DC output voltage VOUT becomes equal to or higher than the noise level threshold at the time when the underline is drawn. Etc. are acquired and recorded in a log. In the example shown in FIG. 3, a decrease in the voltage level of the AC input voltage and an increase in the DC output current are recorded at 10:20:33. In the example shown in FIG. 3, an instantaneous interruption of the AC power supply (a state where the AC input voltage is 0 V) is recorded at 10:20:56.

  Next, FIG. 4 shows a second example of a log generated by the power supply device 10 according to the first embodiment. The example illustrated in FIG. 4 is an example in which, when an abnormality such as an increase in noise is detected in the DC output voltage VOUT, a log is acquired at a cycle shorter than a normal log acquisition cycle after the abnormality is detected. Therefore, in the example shown in FIG. 4, after the abnormality of the DC output voltage VOUT is detected at 10:20:24, the period until the DC output voltage VOUT recovers from the abnormal state to the normal state is 10:20:28. Generate logs at 1 second intervals. Thus, by acquiring the log at a short cycle after the occurrence of an abnormal state, the correlation between the power failure and the abnormality of the telephone system 1 can be grasped more clearly.

  Next, FIG. 5 shows a third example of a log generated by the power supply device 10 according to the first exemplary embodiment. The third example shown in FIG. 5 changes information to be recorded when the same voltage abnormality as that in the first example shown in FIG. 3 occurs. In this third example, as the information to be recorded in the log, the AC input voltage and the usage status of the telephone system 1 such as transmission, incoming call, capture and idle at the time when the DC output voltage VOUT shows abnormality are recorded. Is done. By recording the usage status of the telephone system 1 together with the AC input voltage instead of the electrical information such as the DC output voltage, the relationship between the malfunction of the telephone system 1 and the AC input voltage can be grasped more clearly.

  Further, in the log examples shown in FIGS. 3 to 5, the status of the power supply or the like is shown by specific numerical values, but the log recorded in the memory 44 of the power supply apparatus 10 or the memory 22 of the private branch exchange 20. It is also possible to refer to the log by acquiring and displaying a graph. FIG. 6 shows a display example of a log generated by the power supply device according to the first embodiment.

  In the example shown in FIG. 6, the AC input voltage and the system temperature are displayed as acquisition target information. In the example shown in FIG. 6, the AC input voltage and the system temperature are graphed in time series. In the example shown in FIG. 6, the AC input voltage becomes a voltage value outside the normal operating range (range between the upper limit voltage and the lower limit voltage) in which the system operates normally at around 14: 5: 23. Yes.

  From the above description, in the telephone system 1 according to the first embodiment, the power supply device 10 detects that an abnormal state such as the noise level of the DC output voltage VOUT exceeds the noise level threshold, and the abnormal state is detected. Information such as AC input voltage at the time of being output is output as a log. As a result, in the telephone system 1 according to the first embodiment, it is possible to reliably acquire a log of a power supply abnormality state in which a malfunction may occur while setting a normal log acquisition interval to be long and reducing the log capacity. Can do.

  In particular, in a telephone system, call noise may occur due to power supply abnormality. For this reason, as in the telephone system 1 according to the first embodiment, by acquiring a log such as an AC input voltage according to the occurrence state of the power supply abnormality, call noise is generated due to a problem on the system side. Therefore, it is easy to identify whether or not call noise is generated due to an abnormality in the external AC power supply.

  Further, in the telephone system 1 according to the first embodiment, an arithmetic unit that operates according to a program such as an MPU is used for voltage control of the power supply device 10, and the abnormality of the DC output voltage VOUT is detected by the arithmetic unit. Therefore, in the telephone system 1, a log acquisition function can be added without adding hardware simply by incorporating a noise detection program into a program that defines the operation of the arithmetic unit.

Embodiment 2
In the second embodiment, another form of the power supply device 10 of the first embodiment will be described. FIG. 7 is a block diagram of the power supply device 50 according to the second embodiment. In the description of the second embodiment, the components described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted.

  As shown in FIG. 7, the power supply device 50 is obtained by replacing the power supply circuit 11 of the power supply device 10 with a power supply circuit 51 and replacing the power supply control unit 12 with a power supply control unit 52.

  The power supply circuit 51 uses a PFC circuit (Power Factor Correction circuit) as a circuit for generating the DC output voltage VOUT. The power supply circuit 51 includes a rectifying / smoothing circuit 61, a drive circuit 62, a drive transistor Tr, an inductor L, a diode D, a capacitor C, a heat sink temperature sensor THSEN1, THSEN2, a current detection resistor Rs1, and resistors R1, R2.

  The rectifying / smoothing circuit 61 rectifies an AC input voltage supplied from an AC power source and outputs a DC voltage. This DC voltage is output to the power supply node connected to the positive output terminal of the rectifying and smoothing circuit 61 and the ground node connected to the negative output terminal.

  An inductor L and a diode D are inserted into the power supply node so as to be connected in series. The drive transistor Tr is connected between the node between the inductor L and the diode D and the ground node. A drive signal is given from the drive circuit 62 to the gate of the drive transistor Tr. The drive circuit 62 generates a drive signal from the PWM signal output from the PWM timer 43 of the power supply control unit 52. In the power supply circuit 51, the drive transistor Tr and the diode D are provided with a heat sink. The heat sink provided in the drive transistor Tr is provided with a heat sink temperature sensor THSEN1 that detects the temperature of the heat sink. The heat sink provided in the diode D is provided with a heat sink temperature sensor THSEN2 for detecting the temperature of the heat sink. The temperature information detected by the heat sink temperature sensors THSEN 1 and THSEN 2 is supplied to the AD conversion circuit 71 of the power supply control unit 52.

  Capacitor C is provided between the output-side terminal of power supply circuit 51 among the terminals of diode D and the ground node. The capacitor C smoothes a pulse signal generated by switching between the inductor L and the drive transistor Tr.

  Also in the power supply circuit 51, a current detection resistor Rs1 and resistors R1 and R2 are provided in the same manner as the power supply circuit 11.

  The power control unit 52 is obtained by replacing the AD conversion circuit 41 of the power control unit 12 with an AD conversion circuit 71. The AD conversion circuit 71 is obtained by adding a function to the AD conversion circuit 41 to convert temperature information output from the heat sink temperature sensors THSEN1 and THSEN2 into a digital value.

  In the PFC circuit, when a large fluctuation occurs in the input AC input voltage, the driving transistor Tr and the diode D may be heated. Therefore, in the power supply device 10 according to the second embodiment, in addition to directly observing the noise of the DC output voltage VOUT, the log is generated when the temperature information output by the heat sink temperature sensors THSEN1 and THSEN2 exceeds a preset temperature. Is output.

  In the power supply device 50 according to the second embodiment, a log is generated in accordance with not only fluctuations in the DC output voltage VOUT, such as noise, but also the temperature of the switching elements used for voltage conversion. As a result, the power supply device 50 according to the second embodiment can acquire logs about a wider range of factors than the power supply device 10 according to the first embodiment, and can improve the accuracy of failure analysis of the telephone system.

Embodiment 3
In the third embodiment, a modified example of the power supply device capable of causing a wider range of problems than the power supply device 10 according to the first embodiment will be described. FIG. 8 is a block diagram of the power supply device 80 according to the third embodiment. In the description of the third embodiment, the components described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted.

  As shown in FIG. 8, the power supply device 80 is obtained by adding an X capacitor XC and a current detection unit 82 to the AC power supply line of the power supply device 10 according to the first embodiment. Further, in the power supply device 80, with the addition of the current detection unit 82, an AD conversion circuit 83 in which a function for converting current information output from the current detection unit 82 into a digital value is added to the AD conversion circuit 41 of the power supply control unit 12. A power supply control unit 81 including

  The X capacitor XC is provided between two wirings to which an AC input voltage supplied from an AC power supply is transmitted. The X capacitor XC is for removing a noise component included in the AC input voltage. The current detector 82 detects the current flowing through the X capacitor XC and outputs current information corresponding to the detected current value. The current detector 82 can be formed by using a PCB pattern as a coil.

  Here, an uninterruptible device that outputs a signal having a rectangular wave as an AC power supply may be connected. When a rectangular wave is given as such an AC power supply, the X capacitor XC may be destroyed. This is because when there is a rectangular wave input, the current Ic flowing through the X capacitor XC becomes large, and the X capacitor XC may be excessively heated and destroyed.

Therefore, in the power supply device 80 according to the third embodiment, the current detection unit 82 is provided in series with the X capacitor XC, thereby detecting the current Ic flowing through the X capacitor XC. In the X capacitor XC, when the current Ic flowing in time units increases, the amount of heat generated in the internal resistance increases. There is a relationship of the formula (1) between the current Ic and the calorific value.
P [j / s] = Ic2 × ESR (1)
Here, P is the heat generation amount, and ESR is the resistance value of the internal resistance.
Further, the current Ic can be derived using the equations (2) to (4).
Ic = ΔQ / Δt (2)
Q = CV (3)
Ic = (C × ΔV) / Δt (4)
Here, Q is a capacitance value of the X capacitor XC, V is a voltage applied to the X capacitor XC, and t is time. From the equation (4), it can be seen that the current Ic can be derived by obtaining the magnitude of fluctuation of the AC input voltage per time.

  And in the calculating part 42 of the power supply control part 81, the emitted-heat amount of the internal resistance of X capacitor | condenser XC is calculated based on (1) Formula and (4) Formula. When the heat generation amount of the X capacitor XC becomes larger than an assumed external input noise level threshold (for example, a heat generation amount threshold), the power supply device 80 determines that an abnormality has occurred in the AC power supply and generates a log. .

  As a result, the power supply device 80 according to the third embodiment can record in the log an abnormality of the AC power source that causes a failure of the X capacitor XC, which is difficult to determine only from fluctuations in the DC output voltage VOUT or the like. . When the X capacitor XC is destroyed, the noise level of the AC input voltage increases, and call noise may occur due to the noise. In addition, when the uninterruptible power supply that causes the failure is removed at the time of field verification, there is a problem that it is difficult to identify the cause of the failure of the X capacitor XC. However, according to the power supply device 80 according to the third embodiment, such an abnormality of the AC power supply can be identified from the log from the magnitude of the current Ic flowing through the X capacitor XC.

Embodiment 4
In the fourth embodiment, a modified example of the power supply device capable of causing a wider range of problems than the power supply device 10 according to the first embodiment will be described. FIG. 9 is a block diagram of the power supply device 90 according to the fourth embodiment. In the description of the fourth embodiment, the components described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted.

  As illustrated in FIG. 9, the power supply device 90 is obtained by adding a surge absorber VA and a current detection unit 82 to the AC power supply line of the power supply device 10 according to the first embodiment. Further, in the power supply device 90, with the addition of the current detection unit 82, an AD conversion circuit 92 in which a function for converting current information output from the current detection unit 82 into a digital value is added to the AD conversion circuit 41 of the power supply control unit 12. The power supply control part 91 containing is included.

  The surge absorber VA is a circuit including a varistor. This varistor extracts a surge current from an AC power supply line when a surge current such as a lightning surge occurs in the AC power supply. The surge absorber VA is provided between two wires to which an AC input voltage supplied from an AC power source is transmitted. The current detector 82 detects the current flowing through the surge absorber VA and outputs current information corresponding to the detected current value. The current detector 82 can be formed by using a PCB pattern as a coil.

  When a normal lightning surge is applied to an AC power supply, the surge current becomes sufficiently large in a short time. Therefore, the surge absorber VA functions without a problem with respect to a normal lightning surge. However, if a surge current smaller than a normal lightning surge is applied for a long time, the varistor included in the surge absorber VA may be heated to cause problems such as smoke and fire on the film. When such a problem occurs, the surge absorber VA may be damaged, causing a problem in power quality. However, when such a problem occurs, it is difficult to identify the cause from fluctuations in the DC output voltage VOUT such as noise.

  Therefore, in the power supply device 90 according to the fourth embodiment, the current detection unit 82 is provided in series with the surge absorber VA to detect the current Ic flowing through the surge absorber VA. If it is determined that the current Ic value becomes abnormal in the external input noise level threshold (for example, noise current threshold) and the surge absorber VA may be damaged, the status of the AC power supply etc. at that time is logged. Output as.

  As a result, the power supply device 90 according to the fourth embodiment can record, in a log, an abnormality of the AC power source that causes a failure of the surge absorber VA, which is difficult to determine only from fluctuations in the noise or the like of the DC output voltage VOUT. . When the surge absorber VA is destroyed, the noise level of the AC input voltage increases, and call noise may occur due to the noise. In addition, since the induced lightning surge that causes the failure does not occur at the time of field verification, there is a problem that it is difficult to identify the cause of the failure of the surge absorber VA. However, according to the power supply device 90 according to the fourth embodiment, such an abnormality of the AC power supply can be identified from the log from the magnitude of the current Ic flowing through the surge absorber VA.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Telephone system 10, 50, 80, 90 Power supply device 11, 51 Power supply circuit 12, 52, 81, 91 Power supply control part 13 Insulation circuit 20 Private branch exchange 21 System control part 22, 44 Memory 23, 45 Real-time clock generation part 24 Interface Circuit 31, 34, 61 Rectification smoothing circuit 32, 62 Drive circuit 33 Transformer 41, 71, 83, 92 AD conversion circuit 42 Arithmetic unit 43 PWM timer 82 Current detection unit OVS Voltage observation point OCS Current observation point TM1, TM2 Telephone terminal

Claims (5)

A power supply control unit that outputs a PWM signal having a duty ratio according to a difference between a voltage of the DC system power supply and a preset target voltage;
A power supply circuit that switches the switching element based on the PWM signal and outputs the DC system power supply from an AC power supply supplied from the outside,
The power control unit
The state of the DC system power supply and the state of the AC power supply regardless of whether or not an abnormality has occurred in the AC power supply in response to the noise level of the DC system power supply being equal to or higher than a preset noise level threshold. A power supply unit that outputs logs in association with .   The power control unit detects at least one of C message noise, sophometric noise, ripple noise, spike noise, and voltage fluctuation of the DC system power supply of the DC system power supply, and the noise level to be detected is the noise level. The power supply apparatus according to claim 1, wherein the log is output in response to becoming a threshold value or more. In addition to the case where the noise level of the DC system power supply is equal to or higher than the noise level threshold , the power supply control unit also includes the case where the noise level of the AC power supply is equal to or higher than a preset external input noise level threshold. The power supply device according to claim 1, wherein the log is output in association with a status of an AC power supply and a status of the DC system power supply.   The power supply apparatus according to claim 1, wherein the power supply control unit includes a storage unit that stores the log. A power supply control unit that outputs a PWM signal having a duty ratio according to a difference between a voltage of the DC system power supply and a preset target voltage;
A power supply circuit that switches the switching element based on the PWM signal and outputs the DC system power supply from an AC power supply supplied from the outside;
A private branch exchange that operates based on the DC system power supply and controls connection between the telephone terminal and the office line,
The power control unit
The state of the DC system power supply and the state of the AC power supply regardless of whether or not an abnormality has occurred in the AC power supply in response to the noise level of the DC system power supply being equal to or higher than a preset noise level threshold. A telephone system that outputs logs in association with .

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