JP2017099159A - Power supply device and lighting fixture - Google Patents

Abstract

A power supply device and a lighting fixture that can be reduced in size are provided. A DC power supply unit is connected to input terminals t1 and t2 of a power failure detection circuit 14. One end of the first resistor R1 is connected to the input terminal t1. Between the other end of the first resistor R1 and the input terminal t2, a series circuit of an emitter terminal and a base terminal of the first transistor Q1 and a Zener diode ZD1 is connected. A series circuit of the emitter terminal and the base terminal of the second transistor Q2 and the second resistor R2 is connected between the other end of the first resistor R1 and the input terminal t2. A third resistor R3 is connected between the collector terminal of the second transistor Q2 and the input terminal t2. The third resistor R3 is connected between the gate electrode and the source electrode of the voltage driven transistor Q3. The base terminal of the second transistor Q2 is connected to the collector terminal of the first transistor Q1, and the drain electrode of the voltage driven transistor Q3 is connected to the output terminal t3. [Selection] Figure 2

Description

  The present invention relates to a power supply device and a lighting fixture.

  Conventionally, there has been an emergency lighting device that turns on a light source using a storage battery as a power source when a commercial power supply fails (see, for example, Patent Document 1).

  The lighting device described in Patent Literature 1 includes a power failure detection circuit. The power failure detection circuit compares the level of the smoothed voltage obtained by rectifying, dividing, and smoothing the commercial power supply voltage with the specified switching operation voltage.When the divided voltage drops below the switching operation voltage, the power failure detection signal is output. Output. When the power failure detection circuit outputs a power failure detection signal, the lighting device switches the power source from the commercial power source to the storage battery and turns on the light source with the power supplied from the storage battery.

Japanese Patent Laid-Open No. 2005-73420

  The power failure detection circuit described in Patent Document 1 needs to include a large-capacity smoothing capacitor in order to obtain a constant smoothing voltage after rectifying and dividing the commercial power supply voltage, which increases the size of the power failure detection circuit. There was a problem.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power supply device and a lighting fixture that can be downsized.

  The power supply apparatus according to the present invention has a power supply circuit that generates output power from input power supplied from a DC voltage source, and an input voltage and a threshold voltage that are input from the DC voltage source to a pair of input terminals. A voltage detection circuit for outputting a detection signal from an output terminal, the voltage detection circuit including a first resistor having one end electrically connected to one of the pair of input terminals, and the other end of the first resistance A series circuit of an emitter terminal and a base terminal of the first transistor and a constant voltage element, the other end of the first resistor, and the pair A series circuit of an emitter terminal and a base terminal of the second transistor and a second resistor, and a collector terminal of the second transistor and the pair of input terminals, electrically connected to the other of the input terminals of the second transistor; Between the other And a voltage-driven transistor in which the third resistor is electrically connected between a gate electrode and a source electrode, and a second terminal is connected to the collector terminal of the first transistor. The base terminal of the transistor is electrically connected, and the drain electrode of the voltage-driven transistor is electrically connected to the output terminal.

  Another power supply apparatus according to the present invention includes a power supply circuit that generates output power from input power supplied from a DC voltage source, and an input voltage and a threshold voltage that are input from the DC voltage source to a pair of input terminals. A voltage detection circuit that outputs a corresponding detection signal from an output terminal, the voltage detection circuit including a first resistor having one end electrically connected to one of the pair of input terminals, A series circuit of an emitter terminal and a base terminal of a first transistor and a constant voltage element electrically connected between the other end and the other of the pair of input ends; and the other end of the first resistor A series circuit of an emitter terminal and a base terminal of a second transistor and a second resistor, electrically connected between the other of the pair of input terminals, a collector terminal of the second transistor, and the first Between the other end of the resistor And a voltage-driven transistor having a gate electrode and a source electrode electrically connected to a collector terminal and an emitter terminal of the second transistor, respectively, and a collector terminal of the first transistor. The base terminal of the second transistor is electrically connected, and the drain electrode of the voltage-driven transistor is electrically connected to the output terminal.

  The lighting fixture of this invention was equipped with said power supply device and the fixture main body which hold | maintains the said power supply device, It is characterized by the above-mentioned.

  According to the power supply device and the lighting fixture of the present invention, it is possible to realize downsizing.

It is a block diagram of the lighting fixture of Embodiment 1. FIG. 2 is a circuit diagram of a power failure detection circuit according to Embodiment 1. FIG. 6 is a circuit diagram of a power failure detection circuit according to Embodiment 2. FIG. It is a circuit diagram of the power failure detection circuit of Embodiment 3. FIG. 6 is a circuit diagram of a power failure detection circuit according to a fourth embodiment. FIG. 6A is an external perspective view of a lighting fixture such as an emergency light. FIG. 6B is an external perspective view of a lighting fixture such as a guide light.

  The present embodiment relates to a power supply device and a luminaire, and more particularly, to a power supply device and a luminaire having a function of detecting a power failure state.

  In the following embodiments, a lighting apparatus using a power supply device will be described with reference to the drawings.

  The luminaire described in the following embodiment is an emergency lamp that turns on a light source using a storage battery as a power source in the event of a power failure. The lighting fixture is not limited to an emergency light, and may be a guide light that illuminates a sign for evacuation guidance during energization and power outage. The lighting fixture is not limited to emergency lighting fixtures such as emergency lights and guide lights, and may be lighting fixtures for general lighting. Moreover, although the power supply device of this embodiment is applied to the lighting fixture, power supply devices other than a lighting fixture may be sufficient. The power supply apparatus according to the present embodiment generates an output voltage when the energized state of the external power supply 200 is detected, and a power supply that stops the operation of generating the output voltage when the power failure state of the external power supply 200 is detected. If it is an apparatus, it is applicable also to power supply apparatuses other than a lighting fixture.

(Embodiment 1)
FIG. 1 is a block circuit diagram of a lighting fixture 100 using the power supply device 1 of the first embodiment.

  The luminaire 100 of this embodiment includes a power supply device 1, a charging circuit 2, a storage battery unit 3, a lighting circuit 4, and a light source unit 5.

  The lighting fixture 100 of this embodiment is an emergency light. The luminaire 100 charges the storage battery unit 3 when the power supply voltage Vin input from the external power supply 200 such as a commercial AC power supply is equal to or higher than a predetermined voltage value. When the power supply voltage Vin is lower than a predetermined voltage value, the luminaire 100 turns on the light source unit 5 using the storage battery unit 3 as a power source.

  By the way, in an emergency lighting fixture such as an emergency light, the power source is switched from a commercial AC power source to an emergency power source at the time of a power failure, but instead of switching the power source to an emergency power source after the power source voltage drops to 0V, When the power supply voltage falls below a predetermined voltage value, the power supply is switched to the emergency power supply. For emergency lighting fixtures, a voltage value of 40% or more and 85% or less of the rated input voltage (effective value) according to the technical standards (JIL5501, 5502) of the Japan Lighting Appliances Industry Association (this voltage value is referred to as a switching operation voltage). ) To switch the power supply from a commercial AC power supply to an emergency power supply. Therefore, when the rated input voltage is AC100V, the switching operation voltage is in the range of 40 to 85V, and when the rated input voltage is AC200V, the switching operation voltage is in the range of 80 to 170V. In addition, the lighting fixture 100 of this embodiment can operate | move with a some rated input voltage, for example, can operate | move with the rated input voltage of AC100V-AC242V. In the case of the lighting fixture 100 corresponding to such a universal power supply, the switching operation voltage may be set according to the lowest rated input voltage.

  In the lighting fixture 100 of the present embodiment, when the power supply device 1 detects that the power supply voltage Vin is lower than the switching operation voltage, the power supply device 1 switches the power supply from the external power supply 200 to the storage battery unit 3, and the light source unit 5 is switched. Lights up. Thereby, the surrounding lightness is securable by the light source unit 5 lighting even at the time of a power failure.

  Below, schematic structure of the lighting fixture 100 is demonstrated based on FIG.

  The power supply device 1 converts the AC voltage (power supply voltage Vin) supplied from the external power supply 200 into a DC voltage lower than the effective value of the AC voltage. The power supply device 1 includes a DC power supply unit 11, a converter circuit 12, a power failure detection circuit (voltage detection circuit) 14, and a control circuit 15.

  The DC power supply unit 11 includes a full-wave rectifier DB1 and a capacitor C1. The full-wave rectifier DB1 is formed of, for example, a diode bridge circuit, and full-wave rectifies the AC power supply voltage Vin input from the external power supply 200. The capacitor C1 is connected between the output terminals of the full-wave rectifier DB1. The capacitor C1 is preferably a relatively large capacitor such as an electrolytic capacitor. Capacitor C1 reduces the ripple component of the pulsating voltage output from full-wave rectifier DB1. Therefore, the waveform of the DC voltage output from the DC power supply unit 11 is a voltage waveform in which the ripple component of the pulsating voltage output from the full-wave rectifier DB1 is reduced. Here, the voltage value of the DC voltage output from the DC power supply unit 11 is a voltage value proportional to the effective value of the power supply voltage Vin input from the external power supply 200.

  The converter circuit 12 is a forward type converter circuit including, for example, a transformer T1, a switching element SW1, and a rectifying / smoothing circuit 13. A series circuit of the primary winding of the transformer T1 and the switching element SW1 is connected between both ends of the capacitor C1. A rectifying / smoothing circuit 13 is connected to the secondary winding of the transformer T1. The switching element SW1 is a field effect transistor, for example, and is turned on / off by the control circuit 15. When the control circuit 15 turns on / off the switching element SW1 at a predetermined frequency and duty ratio, the energy accumulated on the primary side of the transformer T1 is supplied to the secondary side of the transformer T1, and the rectifying and smoothing circuit 13 sets a constant voltage value. Is converted to a direct current voltage. The converter circuit 12 is not limited to the forward type converter circuit, and may be a flyback type converter circuit, and can be changed as appropriate.

  The power failure detection circuit 14 determines whether the power supply voltage Vin from the external power supply 200 is equal to or higher than the switching operation voltage based on the voltage value of the input voltage V1 input from the DC power supply unit 11 that is a DC voltage source. A detection signal S1 indicating whether the value is less than the maximum value is output to the control circuit 15. The specific circuit configuration of the power failure detection circuit 14 will be described later.

  The control circuit 15 controls the output voltage of the rectifying / smoothing circuit 13 by turning on / off the transistor Q1 at a predetermined frequency and duty ratio.

  The control circuit 15 has a function of controlling the operation of the lighting circuit 4 according to the detection signal S1 input from the power failure detection circuit 14. When the detection signal S1 indicating that the power supply voltage Vin is equal to or higher than the switching operation voltage is input from the power failure detection circuit 14 to the control circuit 15, the control circuit 15 outputs a turn-off command to the lighting circuit 4, and The light source unit 5 is turned off. When the detection signal S1 indicating that the power supply voltage Vin is lower than the switching operation voltage is input from the power failure detection circuit 14 to the control circuit 15, the control circuit 15 outputs a lighting command to the lighting circuit 4, and the lighting circuit 4 turns on the light source unit 5. In this case, power is supplied to the lighting circuit 4 from the storage battery unit 3, and the light source unit 5 is turned on using the storage battery unit 3 as a power source.

  The control circuit 15 of the present embodiment includes, for example, a microcomputer (microcomputer) as a main configuration. The function of the control circuit 15 is realized by the microcomputer executing the program recorded in the memory of the microcomputer. This program may be recorded in advance in the memory of the microcomputer, may be provided by being recorded on a recording medium such as a memory card, or may be provided through an electric communication line. The control circuit 15 is not limited to a microcomputer as a main component, and may be realized by an analog circuit, and can be changed as appropriate.

  The charging circuit 2 charges the storage battery unit 3 by constantly controlling the charging current input from the power supply device 1 to the storage battery unit 3 in the energized state where the power supply voltage Vin is equal to or higher than the switching operation voltage.

  The storage battery unit 3 includes a plurality of secondary batteries connected in series, for example. The storage battery unit 3 is charged by the charging circuit 2 when power is supplied from the external power source 200, and is discharged when power supply from the external power source 200 is stopped. The secondary battery is preferably a secondary battery such as a cylindrical nickel-hydrogen storage battery or a cylindrical nickel-cadmium storage battery. In addition, when the lighting fixture 100 is a lighting fixture for general lighting, a secondary battery may be a lithium ion secondary battery.

  When the detection signal S1 indicating that the power supply voltage Vin is lower than the switching operation voltage is input from the control circuit 15, the lighting circuit 4 converts the direct current supplied from the storage battery unit 3 to a constant current, and the light source unit 5 To supply. Thereby, in the power failure state in which the power supply voltage Vin is lower than the switching operation voltage, the light source unit 5 is turned on using the storage battery unit 3 as a power source.

  The light source unit 5 includes a plurality of LED chips connected in series, for example. The LED chip is, for example, a blue light emitting diode that emits blue light. The LED chip is mounted on a substrate, and the mounting surface of the substrate is covered with a sealing resin. The sealing resin is preferably a translucent resin material mixed with a fluorescent substance that converts the wavelength of blue light emitted from the LED chip. A part of the blue light emitted from the LED chip is wavelength-converted with a fluorescent material and mixed with the blue light, whereby white illumination light is emitted from the light source unit 5. The light source unit 5 is not limited to the LED chip, and may be a solid light emitting element such as an OLED (Organic Light Emitting Diode) other than the LED chip.

  Next, the circuit configuration of the power failure detection circuit 14, which is a characteristic part of the power supply device 1 of the present embodiment, will be described with reference to FIG. The power failure detection circuit 14 includes a first resistor R1, a first transistor Q1, a Zener diode ZD1 (constant voltage element), a second transistor Q2, a second resistor R2, a third resistor R3, and a voltage drive type. And a transistor Q3. The input voltage V <b> 1 is input from the DC power supply unit 11 to the input ends t <b> 1 and t <b> 2 of the power failure detection circuit 14. Output terminals t3 and t4 of the power failure detection circuit 14 are connected to the control circuit 15, and a detection signal S1 is output from the output terminals t3 and t4 of the power failure detection circuit 14 to the control circuit 15. The input ends t1 and t2 and the output ends t3 and t4 may be components (terminals) for connecting electric wires or the like. For example, a lead of an electronic component or a part of a conductor formed as a wiring on a circuit board But you can.

  One end of the first resistor R <b> 1 is electrically connected to the input end t <b> 1 that is electrically connected to the high-voltage side output end of the DC power supply unit 11 among the pair of input ends t <b> 1 and t <b> 2.

  Between the other end of the first resistor R1 and the input terminal t2, a series circuit of an emitter region and a base region of a pnp-type first transistor (hereinafter referred to as a transistor) Q1 and a Zener diode ZD1 is electrically connected. It is connected to the. Here, the emitter region and the base region of the transistor Q1 serve as a PN junction between the emitter terminal and the base terminal. The cathode of the Zener diode ZD1 is electrically connected to the base terminal of the transistor Q1, and the anode of the Zener diode ZD1 is electrically connected to the input terminal t2. In the circuit of FIG. 2, the emitter terminal of the first transistor Q1 is electrically connected to the other end of the first resistor R1.

  Between the other end of the first resistor R1 and the input end t2, a series circuit of an emitter region and a base region of a pnp-type second transistor (hereinafter referred to as a transistor) Q2 and the second resistor R2. Are electrically connected. Here, the emitter region and the base region of the transistor Q2 serve as a PN junction between the emitter terminal and the base terminal of the transistor Q2. In the circuit of FIG. 2, the emitter terminal of the transistor Q2 is electrically connected to the other end of the first resistor R1. The collector terminal of the transistor Q1 is electrically connected to the base terminal of the transistor Q2. A third resistor R3 is electrically connected between the collector terminal of the transistor Q2 and the input terminal t2.

  The transistors Q1 and Q2 are bipolar transistors, and are pnp bipolar transistors in the circuit of this embodiment. In the present embodiment, the Zener diode ZD1 is provided as the constant voltage element. However, the constant voltage element is not limited to the Zener diode ZD1, and may be a three-terminal regulator or the like.

  The voltage-driven transistor (hereinafter referred to as a transistor) Q3 is a unipolar transistor, and is a MOS (Metal Oxide Semiconductor) type field effect transistor in the present embodiment, for example. The voltage drive transistor Q3 is not limited to a MOST type field effect transistor, and may be a junction type field effect transistor or the like. When the output terminal on the low voltage side of the DC power supply unit 11 is set to the reference potential GND, the third resistor R3 is connected between the collector terminal of the transistor Q2 and the reference potential GND. The gate electrode of the transistor Q3 is connected to the collector terminal of the transistor Q2. The source electrode of the transistor Q3 is connected to the reference potential GND and the output terminal t4. The drain electrode of the transistor Q3 is connected to the control circuit 15 via the output terminal t3. The output terminal t3 is pulled up to a constant voltage via a pull-up resistor, for example. When the transistor Q3 is turned on, the detection signal S1 having a low voltage level is output to the control circuit 15, and when the transistor Q3 is turned off, the detection signal S1 having a high voltage level is output to the control circuit 15.

  A small-capacitance capacitor C2 is connected between the other end of the first resistor R1 and the input terminal t2 in order to smooth the input voltage V1. Further, a capacitor C3 for suppressing malfunction of the transistor Q1 due to noise and a resistor R4 that forms a discharge path of the capacitor C3 are connected in parallel between the base terminal and the emitter terminal of the transistor Q1. Similarly, a capacitor C4 for suppressing malfunction of the transistor Q2 due to noise and a resistor R5 that forms a discharge path of the capacitor C4 are connected in parallel between the base terminal and the emitter terminal of the transistor Q2. The resistor R4 may be used to set an operating current that flows through the Zener diode ZD1 when the transistor Q1 is turned on. Further, the capacitors C3 and C4 are not indispensable components, and may be connected as necessary.

  Next, the operation of the power failure detection circuit 14 will be described below.

  An input voltage V1 having a magnitude proportional to the effective value of the power supply voltage Vin is input from the DC power supply unit 11 to the power failure detection circuit 14. If the effective value of the power supply voltage Vin is equal to or higher than the switching operation voltage, the power failure detection circuit 14 outputs a detection signal S1 having a high voltage level. When the effective value of the power supply voltage Vin falls below the switching operation voltage, the power failure detection circuit 14 outputs a detection signal S1 having a low voltage level. In order to prevent chattering, the power failure detection circuit 14 is switched between a switching operation voltage when the voltage level of the detection signal S1 switches from low to high and a switching operation voltage when the voltage level of the detection signal S1 switches from high to low. A difference (hysteresis) is provided. That is, the switching operation voltage when the voltage level of the detection signal S1 switches from high to low is set to a voltage lower than the switching operation voltage when the voltage level of the detection signal S1 switches from low to high. In the present embodiment, a state where the power failure detection circuit 14 outputs the detection signal S1 having a high voltage level is defined as an energization detection state, and the power failure detection circuit 14 outputs a detection signal S1 having a low voltage level. Is defined as a power failure detection state. In this embodiment, the switching operation voltage when the voltage level of the detection signal S1 switches from high to low is defined as the first switching voltage, and the switching operation voltage when the voltage level of the detection signal S1 switches from low to high. Is defined as the second switching voltage.

  When the input voltage V1 is input from the DC power supply unit 11 to the power failure detection circuit 14, a voltage is applied to the Zener diode ZD1 via the first resistor R1 and between the base terminal and the emitter terminal of the transistor Q1. If the effective value of the power supply voltage Vin is equal to or higher than the first switching voltage in the energization detection state, the circuit constant is set so that a voltage exceeding the Zener voltage is applied to the Zener diode ZD1. When the Zener diode ZD1 is turned on, the voltage Vc2 across the capacitor C2 is clamped to a constant voltage value. Here, when the base-emitter voltage of the transistor Q1 is Vbe1 and the Zener voltage of the Zener diode ZD1 is VZD1, the voltage Vc2 across the capacitor C2 is clamped to the voltage (Vbe1 + VZD1). Hereinafter, this voltage (Vbe1 + VZD1) is referred to as a threshold voltage Vth.

  If the effective value of the power supply voltage Vin is equal to or higher than the first switching voltage in the energization detection state, the Zener diode ZD1 is turned on, the transistor Q1 is turned on, and the transistors Q2 and Q3 are turned off. When the transistor Q1 is turned on and the transistors Q2 and Q3 are turned off, a voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2 is applied to the capacitor C2.

  When the power supply voltage Vin decreases in the energization detection state, the input voltage V1 also decreases. However, if the effective value of the power supply voltage Vin is equal to or higher than the first switching voltage, the input voltage V1 is divided by the first resistor R1 and the second resistor R2. The pressed voltage becomes higher than the threshold voltage Vth. In this case, the voltage Vc2 across the capacitor C2 is clamped to the threshold voltage Vth. As the power supply voltage Vin decreases, the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2 also decreases, so the base current flowing through the transistor Q1 also decreases. The on state is maintained.

  When the effective value of the power supply voltage Vin is lower than the first switching voltage in the energization detection state, the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2 becomes lower than the threshold voltage Vth, and the transistor Q1 No base current flows, and the transistor Q1 is turned off. When the transistor Q1 is turned off, the transistors Q2 and Q3 are turned on, and the detection signal S1 having a low voltage level is output from the output terminal t3 to the control circuit 15. That is, the first switching voltage is the power supply voltage Vin when the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2 is equal to the threshold voltage Vth.

  By the way, the voltage Vc2 across the capacitor C2 immediately before the transistor Q1 is turned off is substantially the same as the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2, and is expressed by the following equation (1). expressed.

Vc2 = V1 * r2 / (r1 + r2) (1)
R1 and r2 are resistance values of the first resistor R1 and the second resistor R2, respectively.

  On the other hand, the voltage Vc2 across the capacitor C2 immediately after the transistor Q1 is turned off is a voltage obtained by dividing the input voltage V1 by the first resistor R1 and the parallel equivalent resistor Rz of the second resistor R2 and the third resistor R3. Is almost the same. When the resistance value of the parallel equivalent resistor Rz is rz, the voltage Vc2 across the capacitor C2 immediately after the transistor Q1 is turned off is expressed by the following equation (2).

Vc2 = V1 * rz / (r1 + rz) (2)
Here, the partial pressure ratio rz / (r1 + rz) in the formula (2) is smaller than the partial pressure ratio r2 / (r1 + r2) in the formula (1). Therefore, the voltage Vc2 applied to the capacitor C2 becomes smaller immediately after the transistor Q1 is turned off because the voltage dividing ratio is smaller than immediately before the transistor Q1 is turned off. Therefore, even if the input voltage V1 fluctuates slightly due to fluctuations in the power supply voltage Vin immediately after the transistor Q1 is turned off, the both-end voltage Vc2 is less likely to exceed the threshold voltage Vth, and chattering is unlikely to occur.

  Further, when the effective value of the power supply voltage Vin increases from this state to become the second switching voltage or higher, the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the parallel equivalent resistor Rz exceeds the threshold voltage Vth, and the transistor A base current starts to flow through Q1, and the transistor Q1 is turned on. When the transistor Q1 is turned on, the transistors Q2 and Q3 are turned off, and the detection signal S1 having a high voltage level is output from the output terminal t3 to the control circuit 15. That is, the second switching voltage is the power supply voltage Vin when the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the parallel equivalent resistor Rz becomes the threshold voltage Vth.

  Here, the voltage Vc2 across the capacitor C2 immediately before the transistor Q1 is turned on becomes substantially the same voltage as the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the parallel equivalent resistor Rz, and the above equation (2 ). On the other hand, the voltage Vc2 across the capacitor C2 immediately after the transistor Q1 is turned on is substantially the same as the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2, and the above equation (1) It is represented by Therefore, immediately after the transistor Q1 is turned on, the voltage dividing ratio is increased and the voltage Vc2 across the capacitor C2 is increased compared to immediately before the transistor Q1 is turned on. Therefore, even if the input voltage V1 slightly fluctuates due to fluctuations in the power supply voltage Vin immediately after the transistor Q1 is turned on, the both-ends voltage Vc2 is less likely to fall below the threshold voltage Vth, and chattering is unlikely to occur.

  As described above, in this embodiment, the voltage dividing circuit is configured by the first resistor R1 and the voltage dividing resistors (second resistor R2 and third resistor R3) connected in series to the first resistor R1. By switching on / off of the transistor Q2 between when the transistor Q1 is on and when it is off, the voltage dividing ratio of the voltage dividing circuit is switched. That is, the voltage dividing ratio of the voltage dividing circuit changes between when the transistor Q1 is turned on and when it is turned off, so that the first switching voltage when the transistor Q1 is turned off and the second switching voltage when the transistor Q1 is turned on. And hysteresis is provided. By providing hysteresis in the first switching voltage and the second switching voltage, chattering of the detection signal S1 is suppressed. The hysteresis between the first switching voltage and the second switching voltage is set to a desired value by the resistance value r3 of the third resistor R3.

  In addition, since the operating current of the power failure detection circuit 14 is suppressed to a relatively small value, resistors having relatively large resistance values can be used for the first resistor R1, the second resistor R2, and the third resistor R3, and the capacitor C2 Even those having a relatively small capacitance value can be sufficiently smoothed. Since the both-ends voltage Vc2 of the capacitor C2 is clamped by the voltage (Vbe1 + VZD1), even if the external power source 200 is a universal power source of AC 100V to 242V, the power failure detection circuit 14 can be configured with components having a relatively low withstand voltage.

  If the voltage ripple of the input voltage V1 is substantially zero, the smoothing capacitor C2 may not be connected in parallel with the series circuit of the base region and the emitter region of the transistor Q1 and the Zener diode ZD1. If necessary to suppress malfunction due to noise, the smoothing capacitor C2 may be connected in parallel with the series circuit of the base region and emitter region of the transistor Q1 and the Zener diode ZD1, and can be appropriately changed. is there.

  As described above, the power supply device 1 of the present embodiment includes the power supply circuit (converter circuit 12) and the voltage detection circuit (power failure detection circuit 14). The power supply circuit generates output power from input power supplied from a DC voltage source (DC power supply unit 11). The voltage detection circuit outputs, from the output terminals t3 and t4, a detection signal S1 corresponding to the level of the input voltage V1 and the threshold voltage Vth input from the DC voltage source to the pair of input terminals t1 and t2. The voltage detection circuit includes a first resistor R1, a first transistor Q1, a constant voltage element (Zener diode ZD1), a second resistor R2, a second transistor Q2, a third resistor R3, and a voltage driven transistor Q3. Is provided. One end of the first resistor R1 is electrically connected to one of the pair of input terminals t1 and t2 (in this embodiment, the input terminal t1). Between the other end of the first resistor R1 and the other of the pair of input terminals t1 and t2 (the input terminal t2 in this embodiment), a series circuit of an emitter region and a base region of the first transistor Q1 and a constant voltage element Are electrically connected. A series circuit of the emitter region and the base region of the second transistor Q2 and the second resistor R2 is electrically connected between the other end of the first resistor R1 and the other of the pair of input ends t1 and t2 (input end t2). It is connected to the. The third resistor R3 is electrically connected between the collector terminal of the second transistor Q2 and the other (input terminal t2) of the pair of input terminals t1 and t2. A third resistor R3 is electrically connected between the gate electrode and the source electrode of the voltage driven transistor Q3. The base terminal of the second transistor Q2 is electrically connected to the collector terminal of the first transistor Q1, and the drain electrode of the voltage-driven transistor Q3 is electrically connected to the output terminal t3.

  In the power supply device 1, when the input voltage V1 is equal to or higher than the threshold voltage Vth, the first transistor Q1 is turned on, and the second transistor Q2 and the voltage driven transistor Q3 are turned off. In this case, a voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2 is applied to the other end of the first resistor R1. On the other hand, when the input voltage V1 falls below the threshold voltage Vth, the first transistor Q1 is turned off, and the second transistor Q2 and the voltage driven transistor Q3 are turned on. In this case, a voltage obtained by dividing the input voltage V1 by the first resistor R1 and the parallel circuit of the second resistor R2 and the third resistor R3 is applied to the other end of the first resistor R1. Since the voltage dividing ratio is switched between when the first transistor Q1 is turned on and when it is turned off, the first switching voltage when the first transistor Q1 is turned off and the second switching voltage when the first transistor Q1 is turned on Is provided with hysteresis to suppress chattering of the detection signal S1. Since the power supply device 1 does not require a high-capacity electrolytic capacitor or the like in the voltage detection circuit, the area necessary for mounting the voltage detection circuit on the substrate can be reduced, and the small power supply device 1 and the lighting fixture 100 can be reduced. Can be realized.

  Each of the first resistor R1, the second resistor R2, and the third resistor R3 may be a single resistor or a plurality of resistors connected in series or in parallel.

(Embodiment 2)
The lighting fixture 100 using the power supply device 1 of Embodiment 2 is demonstrated with reference to drawings. Since the configuration other than the power failure detection circuit 14 is the same as that of the first embodiment, the same reference numerals are given to the same components as those of the first embodiment, and the description thereof is omitted.

  FIG. 3 is a circuit diagram of the power failure detection circuit 14 of the present embodiment. In the power failure detection circuit 14 of the first embodiment, the transistors Q1 and Q2 are pnp bipolar transistors. In the power failure detection circuit 14 of the present embodiment, the transistors Q1 and Q2 are npn bipolar transistors. In the present embodiment, the signal level of the detection signal S1 is reversed in the power failure detection circuit 14 and the power failure detection state and the power failure detection state of the first embodiment, and the signal level of the detection signal S1 is low in the power failure detection state. In the detection state, the signal level of the detection signal S1 becomes high.

  Hereinafter, the circuit configuration of the power failure detection circuit 14 will be described.

  The power failure detection circuit 14 includes a first resistor R1, a first transistor Q1, a Zener diode ZD1 (constant voltage element), a second transistor Q2, a second resistor R2, a third resistor R3, and a voltage drive type. And a transistor Q3. The power failure detection circuit 14 includes a pair of input terminals t1 and t2 to which the input voltage V1 is input from the DC power supply unit 11, and output terminals t3 and t4 that output the detection signal S1.

  One end of the first resistor R <b> 1 is electrically connected to the input end t <b> 1 that is electrically connected to the high-voltage side output end of the DC power supply unit 11 among the pair of input ends t <b> 1 and t <b> 2. Between the other end of the first resistor R1 and the input terminal t2, a series circuit of a Zener diode ZD1 and an npn-type first transistor (hereinafter referred to as a transistor) Q1 is electrically connected. It is connected to the. Here, the base region and the emitter region of the transistor Q1 serve as a PN junction between the base terminal and the emitter terminal. The cathode of the Zener diode ZD1 is electrically connected to the other end of the first resistor R1, and the anode of the Zener diode ZD1 is electrically connected to the base terminal of the transistor Q1. The emitter terminal of the transistor Q1 is electrically connected to the input terminal t2.

  Between the other end of the first resistor R1 and the input end t2, a second resistor R2 and a base region and an emitter region of an npn-type second transistor (hereinafter referred to as a transistor) Q2 are connected in series. The circuit is electrically connected. Here, the base region and the emitter region of the transistor Q2 serve as a PN junction between the base terminal and the emitter terminal. The collector terminal of the transistor Q1 is electrically connected to the base terminal of the transistor Q2, and the emitter terminal of the transistor Q2 is electrically connected to the input terminal t2. A third resistor R3 is electrically connected between the other end of the first resistor R1 and the collector terminal of the transistor Q2. The transistors Q1 and Q2 are bipolar transistors, and are npn-type bipolar transistors in the circuit of this embodiment. In the present embodiment, the Zener diode ZD1 is provided as the constant voltage element. However, the constant voltage element is not limited to the Zener diode ZD1, and may be a three-terminal regulator or the like.

  A voltage-driven transistor (hereinafter referred to as a transistor) Q3 is, for example, a MOS field effect transistor. When the output terminal on the low voltage side of the DC power supply unit 11 is set to the reference potential GND, the emitter terminal of the transistor Q2 is electrically connected to the reference potential GND. The collector terminal of the transistor Q2 is electrically connected to the gate electrode of the transistor Q3. The source electrode of the transistor Q3 is electrically connected to the reference potential GND and the output terminal t4. The drain electrode of the transistor Q3 is electrically connected to the output terminal t3. The output terminal t3 is pulled up to a constant voltage via a pull-up resistor, for example. When the transistor Q3 is turned on, the detection signal S1 having a low voltage level is output to the control circuit 15, and when the transistor Q3 is turned off, the detection signal S1 having a high voltage level is output to the control circuit 15.

  A small-capacitance capacitor C2 is connected between the other end of the first resistor R1 and the input terminal t2 in order to smooth the input voltage V1. A capacitor C3 for suppressing malfunction of the transistor Q1 due to noise and a resistor R4 that forms a discharge path of the capacitor C3 are connected in parallel between the base terminal and the emitter terminal of the transistor Q1. Similarly, a capacitor C4 for suppressing malfunction of the transistor Q2 due to noise and a resistor R5 that forms a discharge path of the capacitor C4 are connected in parallel between the base terminal and the emitter terminal of the transistor Q2. .

  Next, the operation of the power failure detection circuit 14 will be described below.

  An input voltage V1 having a magnitude proportional to the effective value of the power supply voltage Vin is input from the DC power supply unit 11 to the power failure detection circuit 14. If the effective value of the power supply voltage Vin is equal to or higher than the switching operation voltage, the power failure detection circuit 14 outputs a detection signal S1 having a low voltage level. When the effective value of the power supply voltage Vin falls below the switching operation voltage, the power failure detection circuit 14 outputs a detection signal S1 having a high voltage level. In order to prevent chattering, the power failure detection circuit 14 is divided into a switching operation voltage when the voltage level of the detection signal S1 switches from high to low and a switching operation voltage when the voltage level of the detection signal S1 switches from low to high. A difference (hysteresis) is provided. That is, the switching operation voltage when the voltage level of the detection signal S1 switches from low to high is set to a voltage lower than the switching operation voltage when the voltage level of the detection signal S1 switches from high to low. In the present embodiment, a state where the power failure detection circuit 14 outputs the detection signal S1 having a low voltage level is defined as an energization detection state, and the power failure detection circuit 14 outputs a detection signal S1 having a high voltage level. Is defined as a power failure detection state. In this embodiment, the switching operation voltage when the voltage level of the detection signal S1 switches from low to high is defined as the first switching voltage, and the switching operation voltage when the voltage level of the detection signal S1 switches from high to low. Is defined as the second switching voltage.

  When the input voltage V1 is input from the DC power supply unit 11 to the power failure detection circuit 14, a voltage is applied to the Zener diode ZD1 via the first resistor R1 and the base region and emitter region of the transistor Q1. Here, when the effective value of the power supply voltage Vin is equal to or higher than the first switching voltage in the energization detection state, the circuit constant is set so that a voltage exceeding the Zener voltage is applied to the Zener diode ZD1. Therefore, if the effective value of the power supply voltage Vin is equal to or higher than the first switching voltage in the energization detection state, the Zener diode ZD1 is turned on and the voltage Vc2 across the capacitor C2 is clamped to a constant voltage value. Here, when the base-emitter voltage of the transistor Q1 is Vbe1 and the Zener voltage of the Zener diode ZD1 is VZD1, the voltage Vc2 across the capacitor C2 is clamped to the voltage (Vbe1 + VZD1). Hereinafter, this voltage (Vbe1 + VZD1) is referred to as a threshold voltage Vth.

  If the effective value of the power supply voltage Vin is equal to or higher than the first switching voltage in the energization detection state, the Zener diode ZD1 is turned on, the transistor Q1 is turned on, the transistor Q2 is turned off, and the transistor Q3 is turned on.

  When the transistor Q1 is turned on, the transistor Q2 is turned off, and the transistor Q3 is turned on, a voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2 is applied to the capacitor C2.

  When the power supply voltage Vin decreases in the energization detection state, the input voltage V1 also decreases. However, if the effective value of the power supply voltage Vin is equal to or higher than the first switching voltage, the input voltage V1 is divided by the first resistor R1 and the second resistor R2. The pressed voltage becomes higher than the threshold voltage Vth. In this case, the voltage Vc2 across the capacitor C2 is clamped to the threshold voltage Vth. As the power supply voltage Vin decreases, the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2 also decreases, so the base current flowing through the transistor Q1 also decreases. The on state is maintained.

  On the other hand, when the effective value of the power supply voltage Vin is lower than the first switching voltage in the energization detection state, the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2 becomes lower than the threshold voltage Vth. The base current stops flowing through the transistor Q1, and the transistor Q1 is turned off. When the transistor Q1 is turned off, the transistor Q2 is turned on, the transistor Q3 is turned off, and the detection signal S1 having a high voltage level is output from the output terminal t3 to the control circuit 15. That is, the first switching voltage is the power supply voltage Vin when the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2 is equal to the threshold voltage Vth.

  By the way, the voltage Vc2 across the capacitor C2 immediately before the transistor Q1 is turned off is substantially the same as the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2, and is expressed by the following equation (3). expressed.

Vc2 = V1 * r2 / (r1 + r2) (3)
On the other hand, the voltage Vc2 across the capacitor C2 immediately after the transistor Q1 is turned off is a voltage obtained by dividing the input voltage V1 by the first resistor R1 and the parallel equivalent resistor Rz of the second resistor R2 and the third resistor R3. Is almost the same. The voltage Vc2 across the capacitor C2 immediately after the transistor Q1 is turned off is expressed by the following equation (4).

Vc2 = V1 * rz / (r1 + rz) (4)
Here, the partial pressure ratio rz / (r1 + rz) of the equation (4) is smaller than the partial pressure ratio r2 / (r1 + r2) of the equation (3). Therefore, the voltage Vc2 applied to the capacitor C2 becomes smaller immediately after the transistor Q1 is turned off because the voltage dividing ratio is smaller than immediately before the transistor Q1 is turned off. Therefore, even if the input voltage V1 fluctuates slightly due to fluctuations in the power supply voltage Vin immediately after the transistor Q1 is turned off, the both-end voltage Vc2 is less likely to exceed the threshold voltage Vth, and chattering is unlikely to occur.

  Further, when the effective value of the power supply voltage Vin increases from this state to become the second switching voltage or higher, the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the parallel equivalent resistor Rz exceeds the threshold voltage Vth, and the transistor A base current starts to flow through Q1, and the transistor Q1 is turned on. When the transistor Q1 is turned on, the transistor Q2 is turned off, the transistor Q3 is turned on, and the detection signal S1 having a low voltage level is output from the output terminal t3 to the control circuit 15. That is, the second switching voltage is the power supply voltage Vin when the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the parallel equivalent resistor Rz becomes the threshold voltage Vth.

  Here, the voltage Vc2 across the capacitor C2 immediately before the transistor Q1 is turned on becomes substantially the same voltage as the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the parallel equivalent resistor Rz, and the above equation (4 ). On the other hand, the voltage Vc2 across the capacitor C2 immediately after the transistor Q1 is turned on is substantially the same as the voltage obtained by dividing the input voltage V1 by the first resistor R1 and the second resistor R2, and the above equation (3) It is represented by Therefore, immediately after the transistor Q1 is turned on, the voltage dividing ratio is increased and the voltage Vc2 across the capacitor C2 is increased compared to immediately before the transistor Q1 is turned on. Therefore, even if the input voltage V1 slightly fluctuates due to fluctuations in the power supply voltage Vin immediately after the transistor Q1 is turned on, the both-ends voltage Vc2 is less likely to fall below the threshold voltage Vth, and chattering is unlikely to occur.

  As described above, in the power failure detection circuit 14, a voltage dividing circuit is configured by the first resistor R1 and the voltage dividing resistors (second resistor R2 and third resistor R3) connected in series to the first resistor R1. Yes. By switching on / off of the transistor Q2 between when the transistor Q1 is on and when it is off, the voltage dividing ratio of the voltage dividing circuit is switched. That is, the voltage dividing ratio of the voltage dividing circuit changes between when the transistor Q1 is turned on and when it is turned off, so that the first switching voltage when the transistor Q1 is turned off and the second switching voltage when the transistor Q1 is turned on. And hysteresis is provided. By providing hysteresis in the first switching voltage and the second switching voltage, chattering of the detection signal S1 is suppressed. The hysteresis between the first switching voltage and the second switching voltage is set to a desired value by the resistance value r3 of the third resistor R3.

  Since the operating current of the power failure detection circuit 14 is suppressed to a relatively small value, resistors having relatively large resistance values can be used for the first resistor R1, the second resistor R2, and the third resistor R3, and the capacitor C2 is electrostatically Even a capacitor having a relatively small capacitance value can be sufficiently smoothed. Further, since the voltage Vc2 across the capacitor C2 is clamped by the voltage (Vbe1 + VZD1), even if the external power supply 200 is a universal power supply of AC100V to 242V, the power failure detection circuit 14 can be configured with parts having a relatively low withstand voltage. .

  If the voltage ripple of the input voltage V1 is substantially zero, the smoothing capacitor C2 may not be connected in parallel with the series circuit of the base region and the emitter region of the transistor Q1 and the Zener diode ZD1. If necessary to suppress malfunction due to noise, the smoothing capacitor C2 may be connected in parallel with the series circuit of the base region and emitter region of the transistor Q1 and the Zener diode ZD1, and can be appropriately changed. is there.

  In the power failure detection circuit 14 of the present embodiment, a high-capacity electrolytic capacitor or the like is not required, it can be realized with a component having a relatively low withstand voltage, and hysteresis can be provided in the switching operation voltage with a single system circuit. An area necessary for mounting the detection circuit 14 on the substrate can be reduced. Therefore, the small power supply device 1 and the lighting fixture 100 using the same can be realized.

  As described above, the power supply device 1 of the present embodiment includes the power supply circuit (converter circuit 12) and the voltage detection circuit (power failure detection circuit 14). The power supply circuit generates output power from input power supplied from a DC voltage source (DC power supply unit 11). The voltage detection circuit outputs, from the output terminals t3 and t4, a detection signal S1 corresponding to the level of the input voltage input to the pair of input terminals t1 and t2 from the DC voltage source and the threshold voltage Vth. The voltage detection circuit includes a first resistor R1, a first transistor Q1, a constant voltage element (Zener diode ZD1), a second resistor R2, a second transistor Q2, a third resistor R3, and a voltage driven transistor Q3. Is provided. One end of the first resistor R1 is electrically connected to one of the pair of input terminals t1 and t2 (in this embodiment, the input terminal t1). Between the other end of the first resistor R1 and the other of the pair of input terminals t1 and t2 (the input terminal t2 in this embodiment), a series circuit of an emitter region and a base region of the first transistor Q1 and a constant voltage element Are electrically connected. A series circuit of the emitter region and the base region of the second transistor Q2 and the second resistor R2 is electrically connected between the other end of the first resistor R1 and the other of the pair of input ends t1 and t2 (input end t2). It is connected to the. The third resistor R3 is electrically connected between the collector terminal of the second transistor Q2 and the other (input terminal t2) of the pair of input terminals t1 and t2. A collector terminal and an emitter terminal of the second transistor Q2 are electrically connected to the gate electrode and the source electrode of the voltage driven transistor Q3, respectively. The base terminal of the second transistor Q2 is electrically connected to the collector terminal of the first transistor Q1, and the drain electrode of the voltage-driven transistor Q3 is electrically connected to the output terminal t3.

  If the input voltage V1 is equal to or higher than the threshold voltage Vth, the first transistor Q1 is turned on, the second transistor Q2 is turned off, and the voltage-driven transistor Q3 is turned on, and the input voltage V1 is changed between the first resistor R1 and the second resistor R2. The voltage divided by is applied to the other end of the first resistor R1. On the other hand, when the input voltage V1 falls below the threshold voltage Vth, the first transistor Q1 is turned off, the second transistor Q2 is turned on, and the voltage driven transistor Q3 is turned off. In this case, a voltage obtained by dividing the input voltage V1 by the first resistor R1 and the parallel circuit of the second resistor R2 and the third resistor R3 is applied to the other end of the first resistor R1. Since the voltage dividing ratio is switched between when the first transistor Q1 is turned on and when it is turned off, the first switching voltage when the first transistor Q1 is turned off and the second switching voltage when the first transistor Q1 is turned on Is provided with hysteresis to suppress chattering of the detection signal S1. Since the power supply device 1 does not require a high-capacity electrolytic capacitor or the like in the voltage detection circuit, the area necessary for mounting the voltage detection circuit on the substrate can be reduced, and the small power supply device 1 and the lighting fixture 100 can be reduced. Can be realized.

  Each of the first resistor R1, the second resistor R2, and the third resistor R3 may be a single resistor or a plurality of resistors connected in series or in parallel.

(Embodiment 3)
The lighting fixture 100 of Embodiment 3 is demonstrated with reference to FIG.

  Since the lighting fixture 100 of this embodiment differs in the circuit structure of the lighting fixture 100 of Embodiment 1 and the power failure detection circuit 14, and it is the same as that of the lighting fixture 100 of Embodiment 1 except the power failure detection circuit 14, the power failure detection The description of the configuration other than the circuit 14 is omitted.

  FIG. 4 is a circuit diagram of the power failure detection circuit 14 of the present embodiment. In the power failure detection circuit 14 of this embodiment, a fourth resistor R6 and a capacitor C5 are added to the power failure detection circuit 14 described in the first embodiment. Since the configuration other than the fourth resistor R6 and the capacitor C5 is the same as that of the first embodiment, common components are denoted by the same reference numerals, and description thereof is omitted.

  The fourth resistor R6 is electrically connected between the connection point of the first resistor R1 and the capacitor C2 and the emitter terminals of the transistors Q1 and Q2.

  The capacitor C5 is electrically connected in parallel with the series circuit of the fourth resistor R6 and the capacitor C2. The capacitor C5 is a capacitor for suppressing malfunction due to noise, and the capacitor C5 is not essential and may be connected as necessary.

  In the case of the power failure detection circuit 14 described in the first embodiment, the DC power supply unit 11 at the input stage of the power failure detection circuit 14 is a voltage generated in the output voltage (the above input voltage V1) like a capacitor input type rectifier circuit, for example. A power supply circuit in which ripple is suppressed is preferable.

  On the other hand, if the DC power supply unit 11 is a power supply circuit such as a power factor correction circuit, the waveform of the input voltage V1 input from the DC power supply unit 11 to the power failure detection circuit 14 seems to be full-wave rectified from the power supply voltage Vin. Voltage waveform, and the voltage ripple of the input voltage V1 increases.

  Assuming a state where the voltage Vc2 across the capacitor C2 is clamped at the threshold voltage Vth (= Vbe1 + VZD1), the current Ir1 flows through the first resistor R1 only when the input voltage V1 is higher than the threshold voltage Vth. This current Ir1 is expressed by the following equation (5).

Ir1 = (V1-Vbe1-VZD1) / r1 (5)
Therefore, since the base current of the transistor Q1 fluctuates according to the voltage ripple of the input voltage V1, if the hysteresis provided in the switching operation voltage is not sufficient, the chattering of the detection signal S1 may occur.

  On the other hand, in the power failure detection circuit 14 of the present embodiment, the base current flows from the capacitor C2 to the transistor Q1 via the fourth resistor R6, and the fluctuation range of the base current is suppressed by the fourth resistor R6. The chattering of the detection signal S1 can be suppressed.

  The input voltage V1 is smoothed by the capacitor C2, so that the voltage ripple is reduced to some extent. The voltage Vc2 across the capacitor C2 is clamped to a substantially constant voltage by the Zener diode ZD1 before and after the transistor Q1 is turned on. Similarly, the voltage Vc2 across the capacitor C2 is clamped to a substantially constant voltage by the Zener diode ZD1 before and after the transistor Q1 is turned off. Accordingly, since the ripple component of the current flowing through the fourth resistor R6 is suppressed, chattering of the detection signal S1 can be suppressed even when the voltage ripple of the input voltage V1 is relatively large.

  In the power failure detection circuit 14 described in the second embodiment, a fourth resistor may be connected between the connection point of the first resistor R1 and the capacitor C2 and the cathode of the Zener diode ZD1. Thereby, even when the ripple voltage of the input voltage V1 is relatively large, chattering of the detection signal S1 can be suppressed. In addition, a capacitor may be connected in parallel with the series circuit of the fourth resistor and the capacitor C2, and malfunction due to noise can be suppressed.

  The power supply device 1 of this embodiment is electrically connected between the series circuit of the emitter region and base region of the first transistor Q1 and the constant voltage element (Zener diode ZD1) and the other end of the first resistor R1. The fourth resistor R6 is further provided.

  Since the ripple component of the current flowing through the first transistor Q1 via the fourth resistor R6 is suppressed by the fourth resistor R6, the chattering of the detection signal S1 is suppressed even when the voltage ripple of the input voltage V1 is relatively large. Can do.

  The fourth resistor R6 may be a single resistor or a plurality of resistors connected in series or in parallel.

(Embodiment 4)
The lighting fixture 100 of Embodiment 4 is demonstrated with reference to FIG.

  In the lighting fixture 100 of the third embodiment, the power failure detection circuit 14 monitors the input voltage V1 input from the DC power supply unit 11 (first DC power supply unit). The detection circuit 14 monitors the voltage input from the input side of the DC power supply unit 11. In addition, since it is the same as that of the lighting fixture 100 of Embodiment 3 except the power failure detection circuit 14, description is abbreviate | omitted about structures other than the power failure detection circuit 14. FIG.

  In the power failure detection circuit 14 according to the third embodiment, one end of the first resistor R1 is electrically connected to the output terminal on the high voltage side of the DC power supply unit 11. On the other hand, in the power failure detection circuit 14 of the present embodiment, the cathodes of the diodes D1 and D2 are connected to one end of the first resistor R1. The anode of the diode D1 is connected to one end of the external power supply 200, and the anode of the diode D2 is connected to the other end of the external power supply 200. Here, the diodes D1 and D2 and a part of the circuit (diode) of the full-wave rectifier DB1 perform full-wave rectification and convert the alternating-current power supply voltage Vin input from the external power supply 200 into direct current (16). AC / DC converter) is realized.

  The power failure detection circuit 14 receives an input voltage V3 obtained by full-wave rectification of the power supply voltage Vin by the rectifier circuit 16. The power failure detection circuit 14 monitors the input voltage V3 input from the rectifier circuit 16 and performs the same operation as that of the power failure detection circuit 14 of the third embodiment, so that the description thereof is omitted. According to the power failure detection circuit 14 of the present embodiment, even when the input voltage V3 obtained from the input side of the DC power supply unit 11 is monitored, the detection signal S1 corresponding to the level of the power supply voltage Vin and the switching operation voltage is output. be able to.

  Thus, in the power supply device 1, it is also preferable that the DC voltage source includes the DC power supply unit 11 and the AC / DC conversion unit (rectifier circuit 16). The DC power supply unit 11 converts AC power supplied from an AC power supply (external power supply 200) into DC and supplies it to the power supply circuit (converter circuit 12). The AC / DC converter converts the power supply voltage of the AC power source into DC and outputs it to the voltage detection circuit (power failure detection circuit 14).

  Even when a voltage obtained by converting an AC voltage on the input side of the DC power supply unit 11 into a DC voltage by the AC / DC conversion unit is input to the pair of input terminals t1 and t2, the voltage detection circuit is connected to the input terminals t1 and t1. It is possible to output a detection signal corresponding to the level of the input voltage and the threshold voltage input at t2.

  The power failure detection circuit 14 of the first and second embodiments may monitor the input voltage V3 obtained from the input side of the DC power supply unit 11 as in the present embodiment, and the power supply voltage Vin and the switching operation voltage The detection signal S1 corresponding to the height can be output.

  By the way, the external view of the lighting fixture 100 demonstrated in Embodiment 1-4 is shown to FIG. 6A.

  A lighting apparatus 100A shown in FIG. 6A is an emergency light used in a state of being embedded in a ceiling.

  This lighting fixture 100A has a fixture body 20 that houses the power supply device 1. The instrument main body 20 includes a main body 21 and a cover 22.

  The main body 21 is formed in a cylindrical shape, and is inserted into an embedding hole provided in the ceiling.

  The cover 22 has a circular planar shape and is attached to the lower portion of the main body 21. A lens 23 is disposed in the center of the cover 22, and light emitted from the light source unit 5 is irradiated to the outside through the lens 23.

  Since the power source device 1 described in the first to fourth embodiments is held in the fixture main body 20 of the lighting fixture 100A, the lighting fixture 100A can be downsized.

  In addition, the lighting fixture 100 of Embodiment 1-4 is not limited to an emergency light, A guide light may be sufficient.

  FIG. 6B shows an external view of a lighting fixture 100B such as a guide light.

  A luminaire 100B illustrated in FIG. 6B is a guide light used in a state of being attached to a wall, for example.

  This lighting fixture 100B has a fixture body 30 that houses the power supply device 1. The instrument main body 30 includes a body 31, a light emitting unit 32, and a display panel 33.

  The body 31 is formed in a rectangular parallelepiped shape with one surface open, and the configuration of the lighting fixture 100B other than the light source unit 5 is accommodated in the body 31.

  A light emitting unit 32 and a display panel 33 are attached to the opening of the body 31 side by side.

  The light emitting unit 32 houses the light source unit 5 therein, and the light emitted from the light source unit 5 enters the display panel 33.

  For example, a pictogram indicating the evacuation direction is written on the display panel 33.

  In the luminaire 100B, the display panel 33 shines brightly by the light incident on the display panel 33 from the light source unit 5, so that the pictogram written on the display panel 33 is easily visible.

  The lighting fixture 100 according to the present embodiment includes the power supply device 1 described in the first to fourth embodiments and the fixture main bodies 20 and 30 that hold the power supply device 1, so that the lighting fixture 100 can be reduced in size.

  Moreover, the lighting fixture 100 may further be provided with the charging circuit 2, the lighting circuit 4, and the storage battery (storage battery unit 3). When the voltage detection circuit outputs the detection signal S1 indicating that the input voltage V1 is higher than the threshold voltage Vth, the charging circuit 2 may charge the storage battery with the output power of the power supply circuit. When the voltage detection circuit outputs the detection signal S1 indicating that the input voltage V1 is lower than the threshold voltage Vth, the lighting circuit 4 may light the light source (light source unit 5) using the storage battery as a power source.

  Thereby, the lighting fixture 100 which makes a light source light using a storage battery as a power supply at the time of a power failure of a DC voltage source can be realized.

  The configuration described above is merely an example of the present invention. The present invention is not limited to the above-described embodiment, and various modifications can be made according to design or the like as long as the technical idea according to the present invention is not deviated.

1 Power supply device 11 DC power supply (DC voltage source)
12 Converter circuit (power supply circuit)
13 Rectifier smoothing circuit 14 Power failure detection circuit (voltage detection circuit)
16 Rectifier circuit (AC / DC converter, DC voltage source)
DESCRIPTION OF SYMBOLS 100 Lighting fixture 200 External power supply C1 Capacitor DB1 Full wave rectifier Q1 1st transistor Q2 2nd transistor Q3 Voltage drive type transistor R1 1st resistance R2 2nd resistance R3 3rd resistance R6 4th resistance t1, t2 input terminal t3, t4 output End ZD1 Zener diode (constant voltage element)

Claims (6)

A power supply circuit that generates output power from input power supplied from a DC voltage source;
A voltage detection circuit that outputs from the output terminal a detection signal according to the level of the input voltage and the threshold voltage input to the pair of input terminals from the DC voltage source;
The voltage detection circuit includes:
A first resistor having one end electrically connected to one of the pair of input ends;
A series circuit of an emitter terminal and a base terminal of the first transistor and a constant voltage element electrically connected between the other end of the first resistor and the other of the pair of input terminals;
A series circuit of an emitter terminal and a base terminal of a second transistor and a second resistor electrically connected between the other end of the first resistor and the other of the pair of input ends;
A third resistor electrically connected between the collector terminal of the second transistor and the other of the pair of input ends;
A voltage-driven transistor in which the third resistor is electrically connected between a gate electrode and a source electrode;
A base terminal of a second transistor is electrically connected to a collector terminal of the first transistor;
A power supply apparatus, wherein a drain electrode of the voltage-driven transistor is electrically connected to the output terminal. A power supply circuit that generates output power from input power supplied from a DC voltage source;
A voltage detection circuit that outputs from the output terminal a detection signal according to the level of the input voltage and the threshold voltage input to the pair of input terminals from the DC voltage source;
The voltage detection circuit includes:
A first resistor having one end electrically connected to one of the pair of input ends;
A series circuit of an emitter terminal and a base terminal of the first transistor and a constant voltage element electrically connected between the other end of the first resistor and the other of the pair of input terminals;
A series circuit of an emitter terminal and a base terminal of a second transistor and a second resistor electrically connected between the other end of the first resistor and the other of the pair of input ends;
A third resistor electrically connected between the collector terminal of the second transistor and the other end of the first resistor;
A voltage-driven transistor having a gate electrode and a source electrode electrically connected to a collector terminal and an emitter terminal of the second transistor,
A base terminal of a second transistor is electrically connected to a collector terminal of the first transistor;
A power supply apparatus, wherein a drain electrode of the voltage-driven transistor is electrically connected to the output terminal.   And a fourth resistor electrically connected between a series circuit of the emitter terminal and base terminal of the first transistor and the constant voltage element and the other end of the first resistor. The power supply device according to claim 1 or 2, characterized in that   The direct current voltage source converts alternating current power supplied from an alternating current power source into direct current and supplies it to the power supply circuit, and converts the power supply voltage of the alternating current power source into direct current and outputs the direct current to the voltage detection circuit. The power supply device according to claim 1, further comprising an AC / DC converter. The power supply device according to any one of claims 1 to 4,
An instrument body holding the power supply device;
A lighting fixture comprising: A charging circuit, a lighting circuit, and a storage battery;
When the voltage detection circuit is outputting the detection signal indicating that the input voltage is higher than the threshold voltage, the charging circuit charges the storage battery with the output power of the power supply circuit,
When the voltage detection circuit outputs the detection signal indicating that the input voltage is lower than the threshold voltage, the lighting circuit is configured to light a light source using the storage battery as a power source. The lighting fixture according to claim 5.

Images