JP7686952B2 - emergency lighting system - Google Patents

Description

This disclosure relates to an emergency lighting device.

Conventionally, emergency lighting devices have been used to illuminate rooms so that people can safely evacuate during power outages caused by disasters or accidents such as fires and earthquakes in places where a large number of people gather. Emergency lighting devices are supplied with power from an external power source during normal use, and use that power to charge a battery. In emergencies when power is not being supplied from the external power source, the device supplies power from the charged battery to light the light source.

In such emergency lighting devices, a circuit configuration that is commonly used to charge the battery is one that combines a switching circuit with a linear regulator circuit for constant current control (for example, Patent Document 1).

The circuit described in Patent Document 1 uses a linear regulator for constant current control, which may complicate the circuit and lead to increased costs. On the other hand, there is also a method in which the output of the switching circuit is controlled to a constant current without using a linear regulator for constant current control, and the battery is charged with a constant current using only a limiting resistor.

Japanese Patent Application Publication No. 5-308733

However, in a circuit that obtains the operating power supply voltage for a control microcomputer from the secondary side of a switching circuit, when a limiting resistor is used to charge a battery with a constant current, a problem occurs in that the operating power supply voltage for the control microcomputer cannot be obtained if the output voltage on the secondary side of the switching circuit is reduced. To address this issue, it is possible to sufficiently increase the output voltage in order to obtain the operating power supply voltage for the control microcomputer from the secondary side of the switching circuit, but in that case, the value of the limiting resistor needs to be increased, which creates a problem of large circuit losses.

An object of the present disclosure is to provide an emergency lighting device that can charge a battery while suppressing an increase in circuit loss.

The emergency lighting device of the present disclosure comprises a light source unit, a normal power supply circuit that charges a battery that supplies power to the light source unit using an external power source, an emergency power supply circuit that operates when the external power source fails and lights the light source unit using the battery, a control unit that controls the normal power supply circuit, an operating power supply unit that supplies an operating power supply voltage to operate the control unit from the output side of the normal power supply circuit, and a battery voltage detection unit that detects the battery voltage of the battery and inputs the battery voltage to the control unit, wherein the control unit performs constant voltage control to set the output voltage of the normal power supply circuit to be equal to or higher than the operating power supply voltage when the value of the battery voltage is less than a first threshold indicating a value equal to or higher than the operating power supply voltage, performs constant voltage control of the normal power supply circuit when the value of the battery voltage is equal to or higher than a second threshold indicating a fully charged battery voltage state, and performs constant current control of the normal power supply circuit when the value of the battery voltage is equal to or higher than the first threshold and less than the second threshold .

The emergency lighting device disclosed herein can charge the battery while suppressing large losses in the circuit that obtains the operating power supply voltage for the control microcomputer from the secondary side of the switching circuit.

1 is a circuit block diagram of an emergency lighting device according to a first embodiment. FIG. 3A and 3B are diagrams illustrating an output of the normal power supply circuit according to the first embodiment. 3A and 3B are diagrams illustrating an output of the normal power supply circuit according to the first embodiment. 10A and 10B are diagrams illustrating an output of a normal power supply circuit according to a second embodiment. 10A and 10B are diagrams illustrating an output of a normal power supply circuit according to a second embodiment.

Below, an embodiment of the present disclosure will be described with reference to the attached drawings. In each drawing, the same or corresponding parts are given the same reference numerals. Duplicate descriptions will be simplified or omitted as appropriate. Note that the present disclosure is not limited to the embodiment described below.

Embodiment 1.
The emergency lighting device according to the first embodiment will be described below.

Figure 1 is a circuit block diagram of an emergency lighting device 100 according to a first embodiment. The emergency lighting device 100 includes a lighting unit 10 and a light source unit 30. The light source unit 30 is a light source for ensuring brightness in an emergency. The light source unit 30 is, for example, an LED. By using an LED as the light source unit 30, the energy consumption of the emergency lighting device 100 can be reduced. The emergency lighting device 100 is equipped with a battery 50 for lighting the light source unit 30. The lighting unit 10 is supplied with power from an external power source AC and charges the battery 50. The external power source AC is an AC power source. The battery 50 supplies power to the light source unit 30 in an emergency such as a power outage, and lights up the light source unit 30. The battery 50 may be any rechargeable battery, such as a secondary battery such as a nickel-cadmium battery, a nickel-metal hydride battery, or a lithium-ion battery.

The lighting unit 10 includes a diode bridge 1, a normal power supply circuit 2, a battery voltage detection unit 4, a power failure detection circuit 5, an emergency power supply circuit 6, a control unit 7, and an alarm unit 8.

Diode bridge 1 converts AC to DC. The output of diode bridge 1 is connected to normal power supply circuit 2. The low potential side of the output of diode bridge 1 is connected to the ground terminal.

The normal power supply circuit 2 is composed of an isolated flyback circuit. During normal use, the normal power supply circuit 2 receives power from an external AC power supply and charges the battery 50. The normal power supply circuit 2 includes a capacitor 11, a capacitor 13, a capacitor 24, a resistor 12, a resistor 17, a resistor 22, a resistor 23, a transformer 14, a switching element 15, a control IC (Integrated Circuit) 16, a photocoupler 18, a pseudo power failure generating circuit 19, a diode 20, and an electrolytic capacitor 21.

In the normal power supply circuit 2, a capacitor 11 is connected in parallel with the output of the diode bridge 1 to reduce the full wave of the external power supply AC and ripples caused by switching. One end of a resistor 12 and one end of the primary side of a transformer 14 are connected to the positive electrode of the capacitor 11.

A first terminal of a switching element 15 is connected in series to the other end of the primary side of the transformer 14. A second terminal of the switching element 15 is connected to the negative electrode of the capacitor 11. A control terminal of the switching element 15 is connected to a control IC 16. The control terminal is a terminal for switching between the first terminal and the second terminal. The control IC 16 controls the normal power supply circuit 2. Here, normal use refers to a state in which the external power supply AC is not in a power outage state or a pseudo-power outage state. In the following explanation, unless otherwise specified, a power outage state or a pseudo-power outage state will be collectively referred to as a power outage state.

The switching element 15 is, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). When the switching element 15 is a MOSFET, the first terminal is a drain terminal, the second terminal is a source terminal, and the control terminal is a gate terminal. In the switching element 15, the first terminal is connected to the transformer 14, the second terminal is connected to a ground terminal, and the control terminal is connected to the control IC 16.

The control IC 16 is, for example, a PFC (Power Factor Correction) driver. The control IC 16 drives the switching element 15. A circuit in which a resistor 12 and a capacitor 13 are connected in parallel with the capacitor 11 in this order supplies power to the control IC 16.

A photocoupler 18 is connected to the control IC 16 via a resistor 17. The resistor 17 and the photocoupler 18 are provided to input information on the secondary side of the transformer 14 to the control IC 16.

The normal power supply circuit 2 includes a pseudo-power outage generating circuit 19. The pseudo-power outage generating circuit 19 is a circuit that can generate a pseudo-power outage state. The pseudo-power outage generating circuit 19 includes a pseudo-power outage inspection switch, a remote control inspection button, and the like. The pseudo-power outage generating circuit 19 can operate the control IC 16, for example, by using the pseudo-power outage inspection switch as a trigger. This allows the pseudo-power outage generating circuit 19 to create a pseudo-power outage state. Therefore, it is possible to check whether the emergency lighting device 100 operates normally when the external power supply AC is interrupted.

The anode of a diode 20 is connected to one end of the flyback winding on the secondary side of the transformer 14. The diode 20 is connected in series to the secondary side of the transformer 14 and is provided to transmit a stable voltage to the output side. The cathode of the diode 20 is connected to the positive electrode of an electrolytic capacitor 21. The negative electrode of the electrolytic capacitor 21 is connected to the ground terminal.

In the ground path of the normal power supply circuit 2, the primary and secondary sides of the transformer 14 are insulated by a capacitor 24.

The normal power supply circuit 2 is equipped with a normal power supply output voltage detection unit. The normal power supply output voltage detection unit is composed of resistors 22 and 23 connected in series. The normal power supply output voltage detection unit is connected in parallel with electrolytic capacitor 21. The voltage division value of resistors 22 and 23 is input to the microcomputer that is the control unit 7. As a result, the control unit 7 detects the output voltage of the normal power supply circuit 2.

The normal power supply circuit 2, which is a charging circuit, charges the battery 50. The resistor 31 is connected between the flyback winding of the transformer 14 and the battery 50. The other end of the resistor 31 is connected to the positive terminal of the battery 50. The resistor 31 is connected in series with the battery 50 and is provided to limit the current of the battery 50. The negative terminal of the battery 50 is connected to the ground terminal. In other words, the resistor 31 and the battery 50 are connected in series to the output terminal of the normal power supply circuit 2.

The battery voltage detection unit 4 is composed of resistors 51 and 52 connected in series. A series circuit of resistors 51 and 52 is connected in parallel to the battery 50. The battery voltage detection unit 4 is also connected in parallel to the capacitor 32. The voltage obtained by dividing the battery voltage by resistors 51 and 52 is input to the control unit 7. The control unit 7 calculates the potential difference between the output voltage of the normal power supply circuit 2 detected by the normal power supply output voltage detection unit and the voltage obtained by dividing the battery voltage by resistors 51 and 52. The control unit 7 performs calculations based on the calculated potential difference and calculates the target value of the signal that turns the switching element 15 on and off.

The control unit 7 outputs a target value of a signal that turns the switching element 15 on and off from an output terminal. A photocoupler 25 is connected to the output terminal of the control unit 7. The signal output from the control unit 7 is transmitted via the photocoupler 25 to the photocoupler 18 provided on the primary side of the transformer 14.

The output signal of the control unit 7 is transmitted to the control IC 16 via the photocoupler 18 and resistor 17. The control IC 16 controls the switching element 15 to turn on and off based on the output signal received from the control unit 7 so that the target value of the output voltage matches the output voltage of the normal power supply circuit 2. In other words, the control unit 7 controls the normal power supply circuit 2 via the control IC 16. As a result, feedback control is achieved by the normal power supply circuit 2, which is an isolated flyback circuit.

The emergency power supply circuit 6 is composed of a boost switching circuit. The emergency power supply circuit 6 operates in an emergency such as a power outage of the external AC power supply, and boosts the output voltage of the battery 50 to light the light source unit 30. In other words, the emergency power supply circuit 6 receives power from the battery 50, which is a DC power supply, and lights up the light source unit 30.

A capacitor 32 is connected in parallel to the input terminal of the emergency power supply circuit 6. The positive terminal of the capacitor 32 is connected to the positive terminal of the battery 50 and one end of the coil 53. The negative terminal of the capacitor 32 is connected to the ground terminal. The other end of the coil 53 is connected to the anode of the diode 54. The cathode of the diode 54 is connected to the positive terminal of the capacitor 58. The negative terminal of the capacitor 58 is connected to the negative terminal of the capacitor 32. In other words, a series circuit is connected in parallel with the capacitor 32, in which the coil 53, the diode 54, and the capacitor 58 are connected in this order.

A switching element 55 is connected between the connection point of the coil 53 and the diode 54 and the ground terminal. A first terminal of the switching element 55 is connected to the anode of the diode 54. A second terminal of the switching element 55 is connected to the negative electrode of the capacitor 58. A control terminal of the switching element is connected to the control unit 7. The switching element 55 is, for example, a MOSFET.

The anode side of the light source unit 30 is connected to the positive electrode of the capacitor 58. One end of a resistor 59 is connected to the cathode side of the light source unit 30. The other end of the resistor 59 is connected to the negative electrode of the capacitor 58. In FIG. 1, the light source unit 30 is shown as having two LEDs, but the number of light sources provided in the emergency lighting device 100 may be one or more.

The power failure detection circuit 5 is a circuit that detects a power failure state of the external power supply AC. The power failure detection circuit 5 monitors whether or not the external power supply AC is in a power failure state based on an output voltage signal from one end of the flyback winding on the secondary side of the transformer 14, and detects a power failure state of the external power supply AC. The power failure detection circuit 5 is connected to the control unit 7. When the power failure detection circuit 5 detects a power failure of the external power supply AC, it transmits a signal indicating that the external power supply AC is in a power failure state to the control unit 7. When the control unit 7 receives the signal from the power failure detection circuit, it operates the emergency power supply circuit 6. In other words, the control unit 7 controls the emergency power supply circuit 6.

The emergency power supply circuit 6 is equipped with an emergency power supply output voltage detection unit. The emergency power supply output voltage detection unit is composed of resistors 56 and 57 connected in series. The emergency power supply output voltage detection unit is connected in parallel with capacitor 58. The voltage division value of resistors 56 and 57 is input to the control unit 7. As a result, the control unit 7 detects the output voltage of the emergency power supply circuit 6.

The emergency power supply circuit 6 includes an output current detection unit. The output current detection unit is composed of a resistor 59 connected to the cathode side of the LED. When the emergency power supply circuit 6 operates, a voltage obtained by boosting the output voltage of the battery 50 is applied to the capacitor 58. The voltage applied to the capacitor 58 is the output voltage of the emergency power supply circuit 6. A voltage corresponding to the current flowing through the light source unit 30 is applied to the resistor 59. The voltage applied to the resistor 59 is input to the control unit 7. This allows the control unit 7 to detect the output current of the emergency power supply circuit 6. Constant power feedback control is performed by setting a target value for the output current with the output voltage detected by the emergency power supply output voltage detection unit. In this way, the power of the light source unit 30 is controlled to be constant.

Next, the control unit 7 will be described. The control unit 7 is composed of a microcomputer. The microcomputer has a CPU that performs various calculations, a memory, and a timer. The memory is composed of, for example, a non-volatile memory.

The control unit 7 transmits a signal indicating the state of the connected battery 50 to the notification unit 8. When the notification unit 8 receives a signal from the control unit 7, it notifies the outside of the emergency lighting device 100 of the state of the battery 50. The notification unit 8 is, for example, an notification LED, and turns the LED on and off to notify the outside that the state of the battery 50 is abnormal. The notification unit 8 also turns the notification LED on to notify the outside that the state of the battery 50 is normal. The notification unit 8 also turns the notification LED off to notify the outside that the battery 50 is not connected.

When notifying the outside of the state of the battery 50, a charging LED may be used to notify whether charging is being performed by the normal power supply circuit 2. In this way, there is no need to add a new LED as the notification unit 8. Note that the notification unit 8 is not limited to a notification LED, and may be, for example, a sound output unit that outputs sound or voice, such as a speaker, and the same applies to the other forms described below.

Next, the operating power supply unit 3 will be described. The operating power supply unit 3 supplies power to the microcomputer which is the control unit 7. The operating power supply unit 3 supplies a power supply voltage that operates the control unit 7 from the output side of the normal power supply circuit 2. The operating power supply unit 3 is composed of a diode 33 and a regulator 34. The diode 33 is provided on the line that supplies power from the normal power supply circuit 2 to the control unit 7. The anode of the diode 33 is connected to the output side of the normal power supply circuit 2. In other words, the anode of the diode 33 is connected to one end of the flyback winding on the secondary side of the transformer 14. The diode 33 is connected in series with the diode 20, and is provided to transmit a stable voltage to the output side.

The cathode of diode 33 is connected to the control unit 7 on the line that supplies power from the normal power supply circuit 2 to the control unit 7. Specifically, the cathode of diode 33 is connected to regulator 34. Regulator 34 is provided between diode 33 and control unit 7. That is, regulator 34 is provided between the cathode of diode 33 and control unit 7. The output of regulator 34 is connected to the power supply terminal of control unit 7. Regulator 34 stabilizes the output voltage output from diode 33. That is, control unit 7 operates by obtaining power from operating power supply unit 3. Here, the operating power supply voltage that operates control unit 7 is Vcc.

The control unit 7 compares the divided voltage value of the battery voltage input from the battery voltage detection unit 4 with a pre-programmed threshold value, and controls the output voltage of the normal power supply circuit 2. The threshold value may be stored in the memory of the microcomputer, and the control unit 7 may read the threshold value from the memory and compare it with the divided voltage value of the battery voltage. In the following description, the control unit 7 is described as having stored the threshold value in memory in advance.

Figures 2 and 3 are diagrams explaining the output of the normal power supply circuit 2 according to embodiment 1. Figure 2A shows the relationship between voltage and time, and Figure 2B shows the relationship between current and time. Also, Figure 3A shows the relationship between voltage and time, and Figure 3B shows the relationship between current and time. Here, the output voltage of the normal power supply circuit 2 is Vout, the battery voltage detected by the battery voltage detection unit 4 is Vbat, and the threshold value related to voltage pre-stored in the control unit 7 is the first threshold value Vth1. Also, the current for charging the battery 50 is the charging current Ibat.

The following describes the case where the battery 50 is charged by the normal power supply circuit 2. In the following description, the first threshold Vth1 is a value equal to or greater than the operating power supply voltage Vcc that operates the control unit 7. Specifically, the first threshold Vth1 is the voltage obtained by subtracting the forward voltage Vf dropped in the diode 33 and the voltage dropped in the regulator 34 from the output voltage Vout of the normal power supply circuit 2.

When the battery voltage Vbat is less than the first threshold Vth1, the battery 50 needs to be charged, so the control unit 7 sets a feedback target voltage and performs control so that the output voltage Vout of the normal power supply circuit 2 is constant. At this time, as shown in FIG. 2B, the normal power supply circuit 2 performs constant voltage control, so the charging current Ibat is higher than when constant current control is performed.

When the battery 50 is charged by constant current control when the battery voltage Vbat is less than the first threshold Vth1, lowering the output voltage Vout of the normal power supply circuit 2 makes it impossible to ensure the operating power supply voltage Vcc. However, as described above, the first threshold Vth1 is set to be equal to or greater than the operating power supply voltage Vcc, and constant voltage control is performed to ensure the operating power supply voltage Vcc. In other words, the operating power supply voltage Vcc can be ensured by performing constant voltage control with the output voltage Vout set to be equal to or greater than the operating power supply voltage Vcc. Therefore, since there is no need to increase the value of the resistor 31 in order to ensure the operating power supply voltage Vcc from the output voltage Vout of the normal power supply circuit 2, i.e., to increase the output voltage Vout, it is possible to suppress the loss in the circuit from increasing. In other words, the battery 50 can be charged with high efficiency.

When the battery voltage Vbat rises as the battery 50 is charged and reaches or exceeds the first threshold Vth1, the control unit 7 sets a feedback target voltage and performs control so that the voltage across the resistor 31 is constant. At this time, the normal power supply circuit 2 is in constant current control, so the charging current Ibat flowing to the battery 50 is constant. In this way, the control unit 7 controls the charging current Ibat to be constant, so that when the battery 50 is close to full charge, the charging current Ibat does not flow excessively, and it is possible to prevent the battery 50 from becoming overcharged. Note that when the battery voltage Vbat is equal to or greater than the first threshold Vth1, it is not necessarily necessary to control the normal power supply circuit 2 to be in constant current control.

Next, we will explain Figure 3. When the battery voltage Vbat drops and falls below the first threshold Vth1, the control unit 7 sets a feedback target voltage and performs control so that the output voltage Vout of the normal power supply circuit 2 is constant. At this time, as shown in Figure 3B, the normal power supply circuit 2 is in constant voltage control, so Ibat is higher than when constant current control is performed.

The normal power supply circuit 2 can ensure the operating power supply voltage Vcc by setting the first threshold Vth1 to be equal to or higher than the operating power supply voltage Vcc and performing constant voltage control.

As described above, by switching the output voltage Vout of the normal power supply circuit 2 between constant voltage control and constant current control depending on the value of the battery voltage Vbat, it is possible to obtain an emergency lighting device that can suppress large losses in the circuit and charge the battery 50 with high efficiency.

As described above, the emergency lighting device 100 according to the first embodiment includes a light source unit 30, a normal power supply circuit 2 that charges the battery 50 that supplies power to the light source unit 30 using an external power supply AC, an emergency power supply circuit 6 that operates when the external power supply AC fails and lights up the light source unit 30 using the battery 50, a control unit 7 that controls the normal power supply circuit 2, an operating power supply unit 3 that supplies an operating power supply voltage that operates the control unit 7 from the output side of the normal power supply circuit 2, and a battery voltage detection unit 4 that detects the battery voltage of the battery 50 and inputs the battery voltage to the control unit 7. The control unit 7 is an emergency lighting device 100 that performs constant voltage control on the normal power supply circuit 2 when the value of the battery voltage is less than a first threshold value that is equal to or greater than the power supply voltage.

This configuration makes it possible to prevent losses in the circuit that obtains the operating power supply voltage for the control microcomputer from increasing, and to charge the battery 50 with high efficiency.

The emergency lighting device 100 may also be configured to perform constant current control of the normal power supply circuit 2 when the battery voltage value is equal to or greater than the first threshold value.

With this configuration, when the battery 50 is close to being fully charged, the charging current Ibat does not flow excessively, and the battery 50 can be prevented from becoming overcharged.

Embodiment 2.
Next, an emergency lighting device 100 according to a second embodiment will be described. Figures 4 and 5 are diagrams for explaining the output of the normal power supply circuit 2 according to the second embodiment. In the following description, configurations different from those of the first embodiment will be mainly described. The emergency lighting device 100 according to the second embodiment differs from the emergency lighting device 100 of the first embodiment in that the control unit 7 stores the second threshold value Vth2 in the memory, and other configurations are the same as those of the first embodiment, so description thereof will be omitted.

The control unit 7 stores a first threshold value Vth1 and a second threshold value Vth2 in advance in the memory. The second threshold value Vth2 is a threshold value that is greater than the first threshold value Vth1. The first threshold value Vth1 and the second threshold value Vth2 are shown in FIG. 4 and FIG. 5, respectively.

Figure 4 is a diagram explaining the output of the normal power supply circuit 2 according to the second embodiment. Figure 4 shows the transition of the battery voltage Vbat until it exceeds the second threshold voltage Vth2 when the battery 50 is charged by the normal power supply circuit 2.

The second threshold value Vth2 is a value indicating the battery voltage state of the battery 50 when it is fully charged. Here, fully charged does not necessarily mean that the battery 50 is fully charged, but also means that the battery 50 is in a state where its voltage is 80% or more of the voltage when it is fully charged.

When the battery voltage Vbat is equal to or greater than the first threshold and less than the second threshold, the control unit 7 sets a feedback target voltage and performs control so that the voltage across resistor 31 is constant. At this time, the normal power supply circuit 2 is in constant current control, so the charging current Ibat flowing through the battery 50 is constant. Note that the case where the battery voltage Vbat is less than the first threshold Vth1 is omitted because it is the same as in embodiment 1. This also applies to FIG. 5 described below.

When the battery voltage Vbat rises and exceeds the second threshold, the control unit 7 sets a feedback target voltage and performs control so that the output voltage of the normal power supply circuit 2 remains constant. At this time, the normal power supply circuit 2 is in constant voltage control, so the charging current Ibat decreases.

For example, if the battery 50 becomes disconnected, the battery voltage Vbat detected by the battery voltage detection unit 4 will be approximately equal to or close to the output voltage Vout of the normal power supply circuit 2. However, since the normal power supply circuit 2 is under constant voltage control when the battery voltage is fully charged, an overvoltage state will not occur even if the battery 50 becomes disconnected.

Next, we will explain Figure 5. When the battery voltage Vbat drops and falls below the second threshold Vth2, the control unit 7 sets a feedback target voltage and performs control so that the voltage across resistor 31 becomes constant. At this time, as shown in Figure 5B, the normal power supply circuit 2 is in constant current control, so the charging current Ibat becomes constant.

As described above, the emergency lighting device 100 according to embodiment 2 is an emergency lighting device 100 in which, when the value of the battery voltage Vbat is equal to or greater than the second threshold value Vth2, which is a value indicating a fully charged state of the battery voltage Vbat, the control unit 7 performs constant voltage control on the normal power supply circuit 2, and, when the value of the battery voltage Vbat is equal to or greater than the first threshold value Vth1 and less than the second threshold value Vth2, the control unit 7 performs constant current control on the normal power supply circuit 2.

With this configuration, when the battery voltage is fully charged, the normal power supply circuit 2 is under constant voltage control, so even if the battery 50 is disconnected, an overvoltage state will not occur.

Although the embodiments of the present disclosure have been described above, the emergency lighting device 100 of the present disclosure is not limited to the embodiments described in the first and second embodiments, but merely represents a portion of the contents of the present disclosure. The emergency lighting device of the present disclosure can be combined with other known technologies, and it is also possible to omit or change a portion of the configuration, such as by combining them as appropriate, within the scope of the gist of the present disclosure.

1 Diode bridge, 2 Normal power supply circuit, 3 Operating power supply unit, 4 Battery voltage detection unit, 5 Power failure detection circuit, 6 Emergency power supply circuit, 7 Control unit, 8 Notification unit, 10 Lighting unit, 11 Capacitor, 12 Resistor, 13 Capacitor, 14 Transformer, 15 Switching element, 16 Control IC, 17 Resistor, 18 Photocoupler, 19 Pseudo power failure generation circuit, 20 Diode, 21 Electrolytic capacitor, 22 Resistor, 23 Resistor, 24 Capacitor, 25 Photocoupler, 30 Light source unit, 31 Resistor, 32 Capacitor, 33 Diode, 34 Regulator, 50 Battery, 51 Resistor, 52 Resistor, 53 Coil, 54 Diode, 55 Switching element, 56 Resistor, 57 Resistor, 58 Capacitor, 59 Resistor, 100 Emergency lighting device

Claims (3)

A light source unit;
a normal power supply circuit that charges a battery that supplies power to the light source unit using an external power source;
an emergency power supply circuit that operates when the external power supply is interrupted and lights up the light source unit using the battery;
A control unit that controls the normal power supply circuit;
an operating power supply unit that supplies an operating power supply voltage for operating the control unit from an output side of the normal power supply circuit;
a battery voltage detection unit that detects a battery voltage of the battery and inputs the battery voltage to the control unit;
Equipped with
The control unit is
When the value of the battery voltage is less than a first threshold value indicating a value equal to or greater than the operating power supply voltage, the output voltage of the normal power supply circuit is controlled to be equal to or greater than the operating power supply voltage,
When the value of the battery voltage is equal to or greater than a second threshold value that indicates a fully charged state of the battery voltage, the normal power supply circuit is subjected to constant voltage control;
An emergency lighting device that performs constant current control on the normal power supply circuit when the value of the battery voltage is equal to or greater than the first threshold value and less than the second threshold value. 2. The emergency lighting device according to claim 1, further comprising a diode provided on a line supplying power from the normal power supply circuit to the control unit, the anode of which is connected to the output side of the normal power supply circuit and the cathode of which is connected to the control unit. The emergency lighting device according to claim 2 , further comprising a regulator provided between the diode and the control unit.

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