JP2013247720A - Dc power supply - Google Patents

Abstract

Disclosed is a DC power supply device capable of making the conduction width of a phase-controlled AC voltage constant regardless of voltage fluctuations of the AC power supply.
A rectifier circuit that rectifies a phase control voltage output from a phase control dimmer that controls the phase of an AC voltage, and an output that outputs the voltage output from the rectifier circuit as a predetermined DC voltage. Circuits 5 and 6 and a conduction width detection circuit 40 for detecting the conduction width of the phase control voltage phase-controlled by the phase control dimmer 3. The output circuits 5 and 6 are detected by the conduction width detection circuit 40. The DC power supply device 1 outputs a predetermined DC voltage corresponding to the conduction width of the phase control voltage, and the conduction width detection circuit 40 includes a first threshold voltage for detecting the start of conduction of the phase control voltage, and phase control. And a second threshold voltage for detecting the end of voltage conduction, and the second threshold voltage is set lower than the first threshold voltage.
[Selection] Figure 1

Description

  The present invention relates to a DC power supply device that changes a DC output voltage by phase-controlling an AC voltage.

  2. Description of the Related Art Conventionally, an LED lighting device that performs dimming by performing phase control with a dimmer is known (see Patent Document 1).

  Such an LED lighting device is phase-controlled with a phase control dimmer that controls the phase of the AC voltage, a rectifier circuit that rectifies the phase-controlled AC voltage (phase control voltage) output from the phase control dimmer. A conduction width detection circuit for detecting the conduction width of the phase control voltage, and a lighting circuit for lighting the light emitting diode in accordance with the conduction width detected by the conduction width detection circuit.

  The lighting circuit is connected to a primary coil of the transformer connected to the output terminal of the rectifier circuit, a switching element connected in series to the primary coil, a PWM control circuit for turning on and off the switching element, and a secondary coil of the transformer. The light emitting diode is turned on by a DC voltage output from the rectifying / smoothing circuit.

  In the LED lighting device configured as described above, the PWM control circuit outputs a pulse with a duty ratio corresponding to the conduction width detected by the conduction width detection circuit, and the switching element conducts only during the period during which this pulse is output. When a current is passed through the primary coil of the transformer and the switching element is turned off, a high-frequency voltage is output from the secondary coil according to the energy stored in the primary coil, the high-frequency voltage is rectified and smoothed to a DC voltage, The light emitting diode is caused to emit light by this DC voltage.

  By the way, a so-called phase control 2-wire type LED lighting device is known. This LED lighting device outputs an LED output current synchronized with the dimmer by phase-controlling the AC voltage by the dimmer and outputting a dimming signal having the same conduction width as the phase-controlled AC voltage. Is.

JP 2007-35403 A

  However, in such an LED lighting device, as shown in FIG. 6A, the phase-controlled AC voltage (phase control voltage) Va is ideally zero volts in the non-conduction period. Actually, as shown in FIG. 6B, the voltage Vf is generated instead of zero volts in the non-conduction period. Therefore, as shown in FIG. 7, a threshold voltage V1 higher than the voltage Vf is set, and a period in which the full-wave rectified phase control voltage Va is equal to or higher than the threshold voltage V1 is defined as a conduction width of the phase controlled voltage Va. The pulse having this conduction width is used as the dimming signal S1.

  For this reason, when the voltage of the AC power supply fluctuates, for example, as shown in FIG. 8, when the AC voltage Vj is changed to a lower AC voltage Vk, the conduction width W1 becomes smaller, and conversely, when the AC voltage Vj becomes higher, the conduction width Wo. (W1 <Wo) increases. Thus, since the conduction width W also fluctuates when the AC voltage V fluctuates, the output current of the light emitting diode does not fluctuate, which causes a problem of flickering of the light emitting diode.

  An object of the present invention is to provide a DC power supply apparatus that can make the conduction width of a phase-controlled AC voltage constant regardless of voltage fluctuations of the AC power supply.

According to the first aspect of the present invention, there is provided a rectifying circuit for rectifying a phase-controlled phase control voltage output from a phase control device that controls the phase of an AC voltage, and the rectified voltage output from the rectifying circuit is set to a predetermined DC voltage. An output circuit for outputting, and conduction width detecting means for detecting a conduction width of the phase control voltage phase-controlled by the phase control device, wherein the output circuit conducts the phase control voltage detected by the conduction width detection means. A DC power supply device that outputs a predetermined DC voltage according to the width,
The conduction width detecting means has a first threshold voltage for detecting the start of conduction of the phase control voltage and a second threshold voltage for detecting the end of conduction of the phase control voltage,
The second threshold voltage is set lower than the first threshold voltage.

  According to the present invention, the conduction width of the phase-controlled voltage subjected to phase control can be made constant regardless of the voltage fluctuation of the AC power supply.

It is the block diagram which showed the structure of the LED lighting device. It is the circuit diagram which showed the structure of the conduction | electrical_connection width detection circuit of the LED lighting device shown in FIG. It is explanatory drawing which showed the waveform of the phase control voltage by which the phase control was carried out. It is explanatory drawing which showed the waveform of the phase control voltage output from a constant voltage circuit. It is the circuit diagram which showed the structure of the conduction | electrical_connection width detection circuit of 2nd Example. It is the circuit diagram which showed the structure of the conduction | electrical_connection width detection circuit of 3rd Example. (A) is explanatory drawing which showed the waveform of the ideal alternating voltage by which phase control was carried out, (B) is explanatory drawing which showed the waveform of the actual alternating voltage by which phase control was carried out. It is explanatory drawing which showed the relationship between the conduction width of the phase control voltage by which the phase control was carried out, and the light control signal. It is explanatory drawing which shows that the conduction width of a phase control voltage is fluctuate | varied by the fluctuation | variation of a power supply voltage.

  Hereinafter, an embodiment as an embodiment of an LED lighting circuit which is one of DC power supply devices according to the present invention will be described with reference to the drawings.

[First embodiment]
An LED lighting device 1 shown in FIG. 1 includes a phase control dimmer (phase control device) 3 that controls the phase of an AC voltage of an AC power supply (commercial power supply) E, and an AC that is phase-controlled by the phase control dimmer 3. And a lighting circuit 2 that is a DC power supply device that lights the light emitting diode LED of the LED module M based on the voltage (phase control voltage). The phase control dimmer 3, the lighting circuit 2, and the LED module M constitute a lighting fixture.

  The phase control dimmer 3 has a dimming circuit (phase control circuit) (not shown) that turns on (conducts) an internal triac (not shown) based on an external dimming operation means (not shown). Since this configuration is well known, a detailed description thereof will be omitted. With this configuration, when the phase control dimmer 3 conducts the input side and the output side with a triac (not shown) and outputs the AC voltage input from the AC power source E to the input side to the output side, The brightness of the light emitting diode of the LED module M, which will be described later, is dimmed by controlling the phase and width of conduction between the light emitting diode and the output side.

  The lighting circuit 2 includes an input rectification circuit (rectification circuit) 4, a conduction width detection circuit (conduction width detection means) 40 that detects the conduction width of the phase-controlled phase control voltage, an inverter circuit 5, and an output rectification smoothing circuit. 6, an output current detection circuit 7, a dimming signal generation circuit 9, and an output control circuit 10.

  The input rectifier circuit 4 includes a rectifier circuit RC1 for full-wave rectification of the phase control voltage phase-controlled by the phase control dimmer 3, a diode D1 connected to one output terminal of the rectifier circuit RC1, and a rectifier circuit RC1. The other output terminal and the capacitor C1 which is a smoothing circuit connected to the cathode of the diode D1 are included.

  As shown in FIG. 2, the conduction width detection circuit 40 detects the phase control voltage output from the rectifier circuit RC1 by cutting a predetermined voltage or more and outputs the phase control voltage, and detects the start of conduction of the phase control voltage. Zener diode DZ1 for setting a first threshold voltage (Zener voltage Vz) for the above, and transistors Q2, Q3 for setting a second threshold voltage Vh (Vh <Vz) for detecting the end of conduction of the phase control voltage And a light emitting diode Ld1 of the photocoupler PH1.

  The cathode of the Zener diode DZ1 is connected to the output terminal of the constant voltage circuit 41, and the anode is connected to the base of the transistor Q3 via the resistor R5. The anode of the light emitting diode Ld1 is connected to the output terminal of the constant voltage circuit 41 via the resistor R6, and the cathode is connected to the emitter of the transistor Q2. A resistor R7 is connected between the emitter and base of the transistor Q2, and the collector of the transistor Q2 is connected to the base of the transistor Q3.

  The collector of the transistor Q3 is connected to the base of the transistor Q2 via the resistor R8, and the resistor R9 is connected between the base and emitter of the transistor Q3. The emitter of the transistor Q3 is connected to the other output terminal of the rectifier circuit RC1.

  When the Zener diode DZ1 is turned on, the transistors Q3 and Q2 are turned on. Even if the Zener diode DZ1 is turned off during the on period of the transistors Q3 and Q2, the transistors Q3 and Q2 are kept on, and When the constant voltage output from the voltage circuit 41 is equal to or lower than the voltage Vh (voltage close to zero volts) lower than the Zener voltage Vz of the Zener diode DZ1, the transistors Q3 and Q2 are turned off. Even if the constant voltage rises to the voltage Vh, the transistors Q3 and Q2 are not turned on unless the Zener diode DZ1 is turned on. That is, the conduction width detection circuit 40 has a thyristor configuration.

  Further, the Zener voltage Vz is set to a voltage higher than the voltage Vf appearing in the non-conduction period as shown in FIG.

  As shown in FIG. 1, the inverter circuit 5 has a driving circuit IC1 that outputs a control signal that is a pulse at a constant cycle from the output terminal P1, and switching that is turned on only during a period in which the control signal from the driving circuit IC1 is output. It includes an element Q1, a transformer T, and a phototransistor Pd2 of a photocoupler PH2 connected to the input terminal FB of the drive circuit IC1.

  The switching element Q1 is connected in series to the primary coil T1 of the transformer T, and flows current through the primary coil T1 by being conducted.

  The drive circuit IC1 controls the pulse width of the control signal output from the output terminal P1 in accordance with the current flowing through the phototransistor Pd2, and the pulse width is narrowed as the current increases.

  The output rectifying / smoothing circuit 6 includes a diode D2 that rectifies the high-frequency voltage output from the secondary coil T2 of the transformer T, and a capacitor C2 that smoothes the rectified rectified voltage. An LED module M in which a plurality of light emitting diodes (LEDs) are connected in series is connected as a load between the output terminals 6a and 6b of the output rectifying and smoothing circuit 6. Further, an output current detection circuit 7 for detecting a current flowing through the LED module M is provided on the output side of the output rectifying and smoothing circuit 6, and this output current detection circuit 7 is constituted by a resistor R1.

  The dimming signal generation circuit 9 includes a phototransistor Pd1 of the photocoupler PH1 (see FIG. 2) of the conduction width detection circuit 40, and a capacitor C3 connected in series to the phototransistor Pd1.

  The phototransistor Pd1 receives light from the light emitting diode Ld1 of the photocoupler PH1 and is turned on, and charges the capacitor C3 with a constant DC voltage output from the constant voltage circuit 8 only during this conduction period. Yes.

  The output control circuit 10 includes a comparator IC2 operated by a constant voltage supplied from the constant voltage circuit 8, a resistor R3 connected to the output side of the comparator IC2, and a light emitting diode of a photocoupler PH2 connected in series to the resistor R3. Ld2 and the like.

  The non-inverting input terminal of the comparator IC2 is connected to the resistor R1 of the output current detection circuit 7 via the resistor R2, and the voltage generated in the resistor R1 is input to the non-inverting input terminal of the comparator IC2.

  The inverting input terminal of the comparator IC2 is connected to the emitter of the phototransistor Pd1 of the dimming signal generation circuit 9, and the voltage charged in the capacitor C3 is input to the inverting input terminal of the comparator IC2.

  A series circuit of a resistor R and a capacitor C4 is connected between the inverting input terminal and the output terminal of the comparator IC2, and a capacitor C5 is connected in parallel to this series circuit.

  The comparator IC2 uses the charging voltage of the capacitor C3 input to the inverting input terminal as a reference voltage, compares the reference voltage with the voltage of the resistor R1 input to the non-inverting input terminal, and outputs a voltage corresponding to the difference between the output voltage and the output terminal. Output from. A current corresponding to the output voltage of the output terminal of the comparator IC2 flows to the light emitting diode Ld2 of the photocoupler PH2, and the light emitting diode Ld2 emits light according to the current.

The light emitted from the light emitting diode Ld2 is received by the phototransistor Pd2 of the photocoupler PH2 of the inverter circuit 5, and a current corresponding to the amount of received light is output from the terminal FB of the drive circuit IC1 and flows to the photocoupler PH2. The drive circuit IC1 controls the pulse width of the control signal output from the output terminal according to the current flowing through the input terminal FB.
[Operation]
Next, the operation of the LED lighting device 1 configured as described above will be described.

  The AC voltage of the AC power source E is phase-controlled by the phase control dimmer 3, and this phase-controlled phase control voltage Va is rectified by the rectifier circuit RC1 and output as a rectified voltage from the rectifier circuit RC1 as shown in FIG. Is done.

  As shown in FIG. 3A, the phase control voltage Va is output as a phase control voltage Vb after being cut by a constant voltage circuit 41 of the conduction width detection circuit 40 by a predetermined voltage or more.

  When the phase control voltage Vb output from the constant voltage circuit 41 reaches the Zener voltage Vz, the Zener diode DZ1 shown in FIG. 2 is turned on, whereby the transistors Q3 and Q2 are turned on and a current flows to the light emitting diode Ld1 of the photocoupler PH1. Flows, and the light emitting diode Ld1 emits light.

  When the phase control voltage Vb decreases and becomes a voltage Vh (Vh <Vz) close to zero volts, the transistors Q3 and Q2 are turned off, and the light emitting diode Ld1 of the photocoupler PH1 is turned off.

  That is, the light emitting diode Ld1 has a period Td (see FIG. 3A) from the time when the phase control voltage Vb becomes the Zener voltage (first threshold) Vz to the time when the voltage (second threshold) Vh falls, that is, the phase control voltage Vb ( The light is emitted by the conduction width W of Va) (see FIG. 3).

  That is, the conduction width detection circuit 40 detects the conduction width of the phase control voltage Vb and causes the light emitting diode Ld1 to emit light only during the period Td.

  On the other hand, the phase control voltage Va output from the rectifier circuit RC1 (see FIG. 1) is smoothed by charging the capacitor C1 via the diode D1, and is supplied to the inverter circuit 5 as a DC voltage.

  The drive circuit IC1 of the inverter circuit 5 outputs a pulse control signal from the output terminal P1 at regular intervals. The switching element Q1 is turned on only during the period when the control signal is output, and a current flows through the primary coil T1 of the transformer T.

  The switching element Q1 is turned off during a period when the control signal is not output from the output terminal P1 of the drive circuit IC1, and a high-frequency voltage is output from the secondary coil T2 of the transformer T by the energy stored in the primary coil T1 during this off period. The high-frequency voltage is converted to a DC voltage by the output rectifying / smoothing circuit 6, and a current flows through the light emitting diode LED of the LED module M by the DC voltage to emit light.

  The current flowing through the light emitting diode LED of the LED module M is detected by the output current detection circuit 7, and a voltage corresponding to the current is input to the non-inverting terminal of the comparator IC2.

  The dimming signal generation circuit 9 is supplied with the DC voltage output from the output rectifying / smoothing circuit 6 after being converted to a predetermined constant voltage by the constant voltage circuit 8. In addition, the phototransistor Pd1 of the photocoupler PH1 conducts during a period of receiving light (dimming signal) emitted from the light emitting diode Ld1, and during this conduction period, the capacitor C3 is output from the constant voltage circuit 8. Charged by constant voltage.

  Since the light emitting diode Ld1 of the photocoupler PH1 emits light for a period Td that is the conduction width of the phase control voltage Vb, the capacitor C3 is charged only for the period of the conduction width of the phase control voltage Va controlled by the phase control dimmer 3. Then, the voltage of the capacitor C3 increases according to the conduction width. That is, the reference voltage Vx, which is the voltage of the capacitor C3, increases according to the conduction width.

  That is, the voltage (reference voltage) Vx of the capacitor C3 changes corresponding to the conduction width W of the phase control voltage Va (Vb) phase-controlled by the phase control dimmer 3, and the dimming of the phase control dimmer 3 is performed. The reference voltage Vx is changed according to the operation.

  The comparator IC2 outputs a voltage corresponding to the difference (Vi−Vx) between the reference voltage Vx and the voltage Vi corresponding to the current detected by the output current detection circuit 7, and causes the light emitting diode Ld2 of the photocoupler PH2 to emit light.

  The phototransistor Pd2 of the photocoupler PH2 of the inverter circuit 5 receives the light emitted from the light emitting diode Ld2, and a current corresponding to the amount of received light flows to the phototransistor Pd2. That is, a current corresponding to the current flowing through the light emitting diode LED of the LED module M flows through the phototransistor Pd2.

  In the drive circuit IC1, based on the current flowing through the phototransistor Pd2, the difference (Vi−Vx) between the reference voltage Vx of the comparator IC2 and the voltage Vi corresponding to the current detected by the output current detection circuit 7 becomes a predetermined voltage. As described above, a control signal having a predetermined pulse width is output from the output terminal P1. That is, when the difference (Vi−Vx) is equal to or less than a predetermined voltage, the pulse width is increased, and when the difference (Vi−Vx) is equal to or greater than the predetermined voltage, the light emission of the light emitting diode LED of the LED module M is decreased. The amount will be kept constant.

  Then, by changing the reference voltage Vx by the dimming operation of the phase control dimmer 3, the dimming of the light emitting diode LED of the LED module M can be performed.

By the way, as shown in FIG. 3A, the conduction width detection circuit 40 performs a period Td from the time when the phase control voltage Vb (Va) becomes the Zener voltage Vz to the time when the voltage Vh is lower than the Zener voltage Vz. Since the voltage Vh is close to zero volt, even if the AC voltage of the AC power source E varies, the conduction width W is constant without variation. For this reason, the light emitting diode LED of the LED module M that is lit does not flicker due to the voltage fluctuation of the AC power supply E.
[Second Embodiment]
FIG. 4 shows the configuration of the conduction width detection circuit 140 of the second embodiment. The conduction width detection circuit 140 uses a thyristor TH1 instead of the transistors Q2 and Q3 of the first embodiment. The gate of the thyristor TH1 is connected to the anode of the Zener diode DZ1 through the resistor R5, and the thyristor TH1 The anode is connected to the cathode of the light emitting diode Ld1 of the photocoupler PH1. Since other configurations are the same as those in the first embodiment, description thereof will be omitted.

  As in the first embodiment, the conduction width detection circuit 140 conducts the thyristor TH1 when the phase control voltage Vb (Va) reaches the Zener voltage Vz, and the voltage Vh1 is lower than the Zener voltage Vz. The thyristor TH1 is turned off when the voltage falls to. The voltage Vh1 is a voltage close to zero volts.

Other operations are the same as those of the first embodiment, and the effects thereof are also the same as those of the first embodiment, so that the description thereof is omitted.
[Third embodiment]
FIG. 5 shows the configuration of the conduction width detection circuit 240 of the third embodiment. The conduction width detection circuit 240 uses a switching element Q4 and a microcomputer 241 instead of the transistors Q2 and Q3 of the first embodiment.

  The switch element Q4 has a collector connected to the cathode of the light emitting diode Ld1 of the photocoupler PH1, and an emitter connected to the other terminal of the rectifier circuit RC1. Further, the input terminal M1 of the microcomputer is connected to the output terminal of the constant voltage circuit 41, and the output terminal M2 is connected to the base of the switch element Q4.

  When the input voltage (phase control voltage Vb) input to the input terminal M1 rises from a low voltage to a high voltage, the microcomputer 241 outputs a pulse (a dimming signal) from the output terminal M2 when the voltage reaches the voltage Vz. And the switch element Q4 is turned on to cause the light emitting diode Ld1 of the photocoupler PH1 to emit light. When the input voltage drops to the voltage Vh1, the output of the pulse from the output terminal M2 is stopped and the switch element Q4 is turned off. It is to turn off.

  Other operations are the same as those of the first embodiment, and the effects thereof are also the same as those of the first embodiment, so that the description thereof is omitted.

  In the above-described embodiments, the DC power supply device that turns on the LED has been described. However, the present invention is not necessarily limited thereto, and can be applied to other DC power supply devices such as a power supply device that drives a DC motor.

  The present invention is not limited to the above-described embodiments, and design changes and additions are permitted without departing from the scope of the claimed invention.

1 LED lighting device (DC power supply)
3 Phase control means (phase control dimmer)
4 Input rectifier circuit (rectifier circuit)
5 Inverter circuit 6 Output rectification smoothing circuit 40 Conduction width detection circuit (conduction width detection means)

Claims (4)

A rectifying circuit for rectifying a phase-controlled phase control voltage output from a phase control device for phase-controlling an AC voltage, an output circuit for outputting the rectified voltage output from the rectifying circuit as a predetermined DC voltage, and Conduction width detecting means for detecting a conduction width of the phase control voltage phase-controlled by the phase control device, and the output circuit has a predetermined direct current corresponding to the conduction width of the phase control voltage detected by the conduction width detection means. A DC power supply device that outputs a voltage,
The conduction width detecting means has a first threshold voltage for detecting the start of conduction of the phase control voltage and a second threshold voltage for detecting the end of conduction of the phase control voltage,
The DC power supply device, wherein the second threshold voltage is set lower than the first threshold voltage.   The conduction width detecting means has a circuit having a Zener diode for setting the first threshold voltage and a thyristor for setting the second threshold voltage, or a thyristor configuration for setting the Zener diode for setting the first threshold voltage and the second threshold voltage. The DC power supply device according to claim 1, wherein the DC power supply device is constituted by a circuit.   The conduction width detecting means includes a switch element that conducts only for a period according to a conduction width of the phase control voltage, and a microcomputer that controls on / off of the switch element. The microcomputer controls the phase control voltage. When the voltage becomes the first threshold voltage, the switch element is turned on, and when the voltage becomes the second threshold voltage or less, the switch element is turned off. The output circuit depends on the period during which the switch element is on. The DC power supply device according to claim 1, wherein the predetermined DC voltage is output.   A lighting fixture comprising: the DC power supply device according to any one of claims 1 to 3; and a light emitting diode that is turned on by the DC power supply device.