JP2011171017A - Power source circuit, and lighting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power source circuit of simple structure capable of surely turning on and off a semiconductor light emitting element, and to provide a lighting apparatus. <P>SOLUTION: This power source circuit includes: direct current power generator (110, 120); a step-up configuration (130) for stepping-up the power source voltage supplied by the direct current power generator; a step-up controller (150) for controlling operation of the step-up configuration; a step-down configuration (140) for stepping-down the voltage stepped-up by the step-up configuration; and a step-down controller (160) for controlling operation of the step-down configuration to control the current flowing in the semiconductor light emitting element. The power source circuit supplies power to the step-up control circuit from output of the step-down configuration, and when a turn-off signal is input to the power source circuit, the power source circuit stops operation of the step-down configuration to stop output from the step-down configuration. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply circuit for lighting a semiconductor light emitting element such as an LED (light emitting diode), and an illumination device.

  In recent years, LED lighting devices including LED elements as semiconductor light emitting elements have been put into practical use. The LED lighting device includes a power supply circuit and an LED element. The power supply circuit performs rectification, step-up, and step-down with respect to power supplied from a commercial power source. Thereby, a power supply circuit controls the electric current which flows into LED. The light emitting element emits light when current is supplied.

  For example, Patent Document 1 discloses an LED lighting device including a step-up chopper that boosts electric power and a step-down chopper that performs step-down.

JP 2007-234415 A

  When the LED lighting device receives a turn-off signal, the LED lighting device controls each unit so that the semiconductor light emitting element is turned off. As a method of turning off the semiconductor light emitting element, a method of stopping the step-down chopper (step-down circuit) and a method of stopping the step-up chopper (step-up circuit) are conceivable. That is, when turning off the semiconductor light emitting element, the LED lighting device transmits a turn-off signal to a step-up control circuit that controls the step-up circuit or a step-down control circuit that controls the step-down circuit. By stopping the operation, the output is controlled so that the lighting of the semiconductor light emitting element cannot be maintained.

  However, conventionally, since the power of the boost control circuit is received from the output of the rectifier circuit that performs rectification or the output of the boost circuit, even if the step-down control circuit is stopped in response to the turn-off signal, Operation continues. Thereby, a high voltage | pressure charge part is maintained in the lighting circuit of a semiconductor light-emitting device. As a result, there are problems such as an increase in standby power, a shortening of the life of the LED lighting device, or a danger due to a high voltage.

  Further, even if the boost control circuit is stopped in response to the received turn-off signal, the path for supplying power from the commercial power supply to the step-down circuit remains formed, so that the semiconductor light emitting element is driven by the power supplied from the commercial power supply. May light up incorrectly.

  Further, when both the step-down control circuit and the step-up control circuit are stopped according to the received turn-off signal, it is necessary to connect the turn-off signal to the step-down control circuit and the step-up control circuit. That is, it is necessary to add a circuit, a component, etc., and there is a problem that the apparatus is increased in size and complexity.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a power supply circuit and a lighting device that can reliably turn off a semiconductor light emitting element with a simple configuration.

  The power supply circuit according to claim 1 includes: DC power generating means; boosting means for boosting a power supply voltage supplied by the DC power generating means; boost control means for controlling the operation of the boosting means; A step-down means for stepping down the voltage stepped up by step; a step-down control means for controlling the operation of the step-down means and controlling a current flowing through the semiconductor light emitting element; and supplying power to the step-up control circuit from the output of the step-down means A power supply means; and a light extinguishing means that stops the operation of the step-down means and stops the output from the step-down means when an extinguishing signal is input.

  In the present invention and each of the following inventions, each configuration is as follows unless otherwise specified.

  The semiconductor light emitting element is, for example, a light emitting diode or an organic EL element. The semiconductor light emitting device may be provided with a plurality of semiconductor light emitting devices that emit light of different wavelengths.

  According to the present invention, in the power supply circuit, when the turn-off signal is input from the turn-off means, the operation of the step-down means is stopped. Since the step-down unit stops and the output from the step-down unit stops, no current is supplied to the semiconductor light-emitting element, and the semiconductor light-emitting element is turned off. Further, since the boost control means operates by receiving electric power from the output of the step-down means, when the extinguishing signal is input and the step-down means stops, the operation stops. The boosting means stops its operation when no control signal is input from the boosting control means. In other words, the power supply circuit can stop the boosting means together by stopping the voltage lowering means.

  A power supply circuit according to a second aspect is the power supply circuit according to the first aspect, wherein the direct-current power generated by the direct-current power generating means is supplied to the step-down means to start the step-down means. It is characterized by comprising starting means for starting the supply of electric power.

  According to the present invention, in the power supply circuit, when the semiconductor light emitting element is turned on, the DC power generating means turns on the switch of the step-down means. As a result, the current output from the DC power generation means flows to the semiconductor light emitting element via the step-down means. Thereby, the semiconductor light emitting element is turned on. The power supply circuit can supply power to the step-up control circuit and the step-down control circuit to start operation.

  According to a third aspect of the present invention, there is provided a lighting device comprising: a semiconductor light emitting element; a power supply circuit according to the first or second aspect; and an instrument body provided with the power supply circuit.

  According to the present invention, when the turn-off signal is input, the lighting device can stop the semiconductor light emitting element and the boosting unit by stopping the bucking unit. Thereby, the illuminating device which can perform lighting and extinction of a semiconductor light-emitting element reliably with a simple structure can be provided.

  According to the first aspect of the present invention, when the turn-off signal is input, the power supply circuit can stop the step-up means together and thereby stop the step-up means together. The semiconductor light emitting element can be turned off.

  According to the invention of claim 2, when the semiconductor light emitting element is turned on, the power supply circuit supplies power to the semiconductor light emitting element, the step-up control circuit, and the step-down control circuit by turning on the step-down means by the DC power generation means. In addition, since the operation can be started, the lighting of the semiconductor light emitting element can be surely started without using a complicated configuration.

  According to invention of Claim 3, it can be set as the illuminating device which has the effect of Claim 1 or 2.

FIG. 1 is an explanatory diagram for explaining a configuration example of a lighting apparatus according to an embodiment of the present invention. FIG. 2 is an explanatory diagram for explaining a configuration example of a lighting apparatus according to another embodiment of the present invention. FIG. 3 is an explanatory diagram for explaining a configuration example of a lighting apparatus according to still another embodiment of the present invention.

  Hereinafter, a power supply circuit and an illumination device according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram for explaining a configuration example of a lighting device 100 according to an embodiment of the present invention.
The lighting device 100 includes a power system 110, a rectifier circuit 120, a booster circuit 130, a step-down circuit 140, a step-up control circuit 150, a step-down control circuit 160, a turn-off circuit 170, an LED 180 as a semiconductor light emitting element, and a starter circuit 190.

  The power system 110 is an AC power source such as a commercial power source. The power system 110 may be a connection terminal connected to an AC power source.

  The rectifier circuit 120 includes a rectifier bridge including a plurality of diodes. The rectifier circuit 120 rectifies AC power supplied from the power system 110 into DC power.

  The booster circuit 130 includes a booster chopper. That is, the booster circuit 130 includes a reactor L1, a transistor Tr1, a diode D1, and a capacitor C2. The transistor Tr1 and the capacitor C2 are connected in parallel with the rectifier circuit 120. Reactor L1 is connected between transistor Tr1 and rectifier circuit 120. The diode D1 is connected between the transistor Tr1 and the capacitor C2. The booster circuit 130 functions as a booster.

  The step-down circuit 140 includes a step-down chopper. That is, the step-down circuit 140 includes a transistor Tr2, a diode D2, a reactor L2, and a capacitor C3. The diode D2 and the capacitor C3 are connected in parallel with the capacitor C2. The transistor Tr2 is connected between the capacitor C2 and the diode D2. Reactor L2 is connected between diode D2 and capacitor C3. The step-down circuit 140 functions as a step-down unit.

  The boost control circuit 150 generates a control signal for controlling ON / OFF of the transistor Tr1 based on a preset duty ratio. The step-up control circuit 150 controls the ON / OFF of the transistor Tr1 by inputting the generated control signal to the transistor Tr1. As a result, the booster circuit 130 and the booster control circuit 150 control the voltage generated across the capacitor C2. That is, the booster circuit 130 boosts and outputs a voltage generated across the rectifier circuit 120.

  The step-up control circuit 150 operates by receiving power generated by the reactor L3 that is magnetically connected to the reactor L2 of the step-down circuit 140. Reactor L3 receives the magnetic flux generated by the current passing through reactor L2, generates power, and supplies the generated power to boost control circuit 150.

  The step-up control circuit 150 may be configured to receive power by being electrically connected to the inside of the step-down circuit 140 or the output terminal of the step-down circuit 140. In this case, the boost control circuit 150 receives power from at least a location where the current is turned on / off according to the operation of the step-down circuit 140.

  The step-down control circuit 160 detects the current value of the current flowing through the LED 180. The step-down control circuit 160 generates a control signal for controlling ON / OFF of the transistor Tr2 based on a preset current value and the detected current value. The step-down control circuit 160 controls ON / OFF of the transistor Tr2 by inputting the generated control signal to the transistor Tr2. Thereby, the step-down circuit 140 and the step-down control circuit 160 control the voltage generated across the capacitor C3. That is, the step-down circuit 140 controls the voltage generated at both ends of the capacitor C3 so that the current flowing through the LED 180 becomes a constant value.

  The step-down control circuit 160 operates by receiving electric power generated by the reactor L4 that is magnetically connected to the reactor L2 of the step-down circuit 140. Reactor L4 receives the magnetic flux generated by the current passing through reactor L2, generates electric power, and supplies the generated electric power to step-down control circuit 160.

  Note that the step-down control circuit 160 may be configured to receive power by being electrically connected to the inside of the step-down circuit 140 or the output terminal of the step-down circuit 140. In this case, the step-down control circuit 160 receives power from at least a location where the current is turned ON / OFF according to the operation of the step-down circuit 140.

  The extinguishing circuit 170 functioning as the extinguishing means inputs an extinguishing signal to the step-down control circuit 160 and stops the operation of the step-down control circuit 170. Thereby, the light-off circuit 170 turns off the LED 180. The extinguishing circuit 170 includes, for example, a photosensor that detects light, and inputs the extinguishing signal to the step-down control circuit 160 when the light detected by the photosensor is equal to or greater than a predetermined value. The photosensor is configured by, for example, a sensor that detects the amount of light, an infrared sensor, or the like.

  Note that the light-off circuit 170 may be configured to input a light-off signal to the step-down control circuit 160 based on detection results of other sensors. Further, the light-off circuit 170 may be configured to input another light-off signal to the step-down control circuit 160 when receiving a signal from an external operation unit.

  Further, the light-off circuit 170 may be configured to input a light-off signal to the step-down control circuit 160 every predetermined time. Thereby, for example, the lighting device 100 can control the turning on or off of the LED 180 at a preset time. Further, the light-off circuit 170 may be configured to input a light-off signal to the step-down control circuit 160 after a predetermined time elapses after the LED 180 is turned on. Moreover, you may combine said structure suitably. The extinguishing control means in this embodiment includes an extinguishing circuit 170 and a step-down control circuit 160 to which an extinguishing signal of the extinguishing circuit 170 is input.

  The LED 180 emits light according to a current that flows according to an applied voltage.

  The starter circuit 190 includes a wiring connected between the step-down control circuit 160 and the output terminal of the rectifier circuit 120 and a wiring connected between the step-down control circuit 160 and GND. The starter circuit 190 includes a resistor R1 and a resistor R2. The resistor R1 is connected between the step-down control circuit 160 and the output terminal of the rectifier circuit 120. The resistor R2 is connected between the step-down control circuit 160 and GND.

  When a turn-off signal is input from the turn-off circuit 170 to the step-down control circuit 160, the step-down control circuit 160 turns off the transistor Tr2 of the step-down circuit 140. As a result, no current flows through the reactor L2 and the capacitor C3. As a result, the LED 180 is turned off.

  In addition, since no current flows through reactor L2, the power supplied from reactor L3 to boost control circuit 150 is interrupted. Further, the power supplied from reactor L4 to step-down control circuit 160 is interrupted.

  Since the boost control circuit 150 is not supplied with power from the power supply system 110, it stops operating. The transistor Tr1 of the booster circuit 130 is turned off because no signal is input from the booster control circuit 150. For this reason, the booster circuit 130 stops its operation.

  As described above, the step-up control circuit 150 of the lighting device 100 receives power from the subsequent stage from the transistor Tr2 of the step-down circuit 140. With this configuration, the lighting device 100 can also stop the operation of the booster circuit 130 when stopping the step-down circuit 140 from the step-down control circuit 160. Further, the circuit configuration can be simplified as compared with the case where both the step-up control circuit 150 and the step-down control circuit 160 are stopped from the turn-off circuit 170.

  When lighting the lighting device 100, the lighting device 100 turns on a switch (not shown) provided between the power supply system 110 and the rectifier circuit 120. Thereby, AC power is supplied from the commercial power supply to the rectifier circuit.

  The rectifier circuit 120 converts AC power into DC power. The voltage output from the rectifier circuit 120 is applied to the resistor R1 and the resistor R2 of the starting circuit 190. The voltage divided by the resistors R1 and R2 is applied to the base of the transistor Tr2 of the step-down circuit 140. The transistor Tr2 turns on the current path by the voltage applied to the base.

  As a result, the current output from the rectifier circuit 120 flows through the transistor Tr2, the reactor L2, and the LED 180.

  Moreover, since a current flows through the reactor L2, the reactor L3 and the reactor L4 receive the magnetic flux generated by the reactor L2 and generate electric power. As a result, the boost control circuit 150 and the step-down control circuit 160 operate by receiving the generated power. As a result, the booster circuit 130 and the step-down circuit 140 can start normal operation and supply predetermined power to the LED 180. As a result, the LED 180 is turned on.

  Note that the LED 180 may be configured to be removable from the power supply circuit of the lighting device 100. In this case, the illumination device 100 includes a terminal to which an LED or another light emitting element can be attached.

  In the above-described embodiment, an example in which a step-down chopper is provided as the step-down circuit 140 has been described. However, the present invention is not limited to this configuration. The step-down circuit 140 may be composed of other step-down elements.

FIG. 2 is an explanatory diagram for describing a configuration example of an illumination device 200 according to another embodiment of the present invention.
The lighting device 200 includes a power system 210, a rectifier circuit 220, a booster circuit 230, a step-down circuit 240, a step-up control circuit 250, a step-down control circuit 260, a turn-off circuit 270, an LED 280 as a semiconductor light emitting element, and a starting circuit 290. The power system 210, the rectifier circuit 220, the booster circuit 230, the extinguishing circuit 270, the LED 280, and the starting circuit 290 are the power system 110, the rectifying circuit 120, the boosting circuit 130, the extinguishing circuit 170, the LED 180, and the starting circuit illustrated in FIG. Since the configuration is the same as that of the circuit 190, detailed description thereof is omitted.

  The step-down circuit 240 includes a flyback circuit, and includes a transformer 241, a transistor Tr3, a diode D3, and a capacitor C3. The transformer 241 includes a reactor L5 and a reactor L6 that are magnetically connected. Reactor L5 is connected to the primary side (input side) of the transformer. Further, the reactor L6 is connected to the secondary side (output side) of the transformer.

  The transistor Tr3 is connected in series with the reactor L5. Further, the capacitor C2 of the booster circuit 230, the transistor Tr3, and the reactor L5 are connected in parallel.

  The diode D3 is connected in series with the reactor L6. The capacitor C3 is connected in parallel with the diode D3 and the reactor L6.

  Reactor L5 generates magnetic flux according to the input current. Reactor L6 receives the magnetic flux generated by reactor L5 and generates electric power. Thereby, reactor L6 supplies electric power to the secondary side.

  Reactor L5 and reactor L6 differ in the number of windings. The ratio of the number of windings of reactor L5 and the number of windings of reactor L6 corresponds to the ratio of the voltage at the input terminal of reactor L5 and the voltage generated at the output terminal of reactor L6. For example, by making the number of windings of the reactor L5 larger than the number of windings of the reactor L6, the transformer 241 can step down the voltage according to the ratio of the number of windings. Thereby, the transformer 241 converts the high voltage output from the booster circuit 230 into a low voltage.

  The boost control circuit 250 generates a control signal for controlling ON / OFF of the transistor Tr1 based on a preset duty ratio. The boost control circuit 250 controls ON / OFF of the transistor Tr1 by inputting the generated control signal to the transistor Tr1. Thereby, the booster circuit 230 and the booster control circuit 250 control the voltage generated across the capacitor C2. That is, the booster circuit 230 boosts and outputs a voltage generated across the rectifier circuit 220.

  The step-up control circuit 250 operates by receiving electric power generated by the reactor L7 that is magnetically connected to the reactor L5 of the step-down circuit 240. Reactor L7 receives the magnetic flux generated by the current passing through reactor L5, generates electric power, and supplies the generated electric power to boost control circuit 250.

  The step-up control circuit 250 may be configured to receive power by being electrically connected to the inside of the step-down circuit 240 or the output terminal of the step-down circuit 240. In this case, the step-up control circuit 250 receives power from at least a location where the current is turned on / off according to the operation of the step-down circuit 240.

  The step-down control circuit 260 detects the current value of the current flowing through the LED 280. The step-down control circuit 260 generates a control signal for controlling ON / OFF of the transistor Tr3 based on a preset current value and a detected current value. The step-down control circuit 260 controls ON / OFF of the transistor Tr3 by inputting the generated control signal to the transistor Tr3. Thus, the step-down circuit 240 and the step-down control circuit 260 control the voltage generated across the capacitor C3. That is, the step-down circuit 240 controls the voltage generated at both ends of the capacitor C3 so that the current flowing through the LED 280 becomes a constant value.

  The step-down control circuit 260 receives power generated by the reactor L8 that is magnetically connected to the reactor L5 of the step-down circuit 240 and operates. Reactor L8 receives the magnetic flux generated by the current passing through reactor L6, generates electric power, and supplies the generated electric power to step-down control circuit 260.

  Note that the step-down control circuit 260 may be configured to receive power by being electrically connected to the inside of the step-down circuit 240 or the output terminal of the step-down circuit 240. In this case, the step-down control circuit 260 receives power from at least a location where the current is turned ON / OFF according to the operation of the step-down circuit 240.

  When a turn-off signal is input to the step-down control circuit 260 from the turn-off circuit 270 functioning as a turn-off means, the step-down control circuit 260 turns off the transistor Tr3 of the step-down circuit 240. As a result, no current flows through reactor L5. Since no magnetic flux is generated, the power supplied from the reactor L6 to the secondary side of the step-down circuit 240 is interrupted. As a result, the LED 280 is turned off.

  Further, since no current flows through reactor L5, the electric power supplied from reactor L7 to boost control circuit 250 is interrupted. Further, the power supplied from reactor L8 to step-down control circuit 260 is interrupted.

  The boost control circuit 250 stops operation because it is not supplied with power from the power supply system 210. The transistor Tr1 of the booster circuit 230 is turned off because no signal is input from the booster control circuit 250. For this reason, the booster circuit 230 stops its operation.

  As described above, the step-up control circuit 250 of the lighting device 200 receives power from the secondary side of the step-down circuit 240. With this configuration, the lighting device 200 can also stop the operation of the booster circuit 230 when stopping the step-down circuit 240 from the step-down control circuit 260. Further, the circuit configuration can be simplified as compared with the case where both the step-up control circuit 250 and the step-down control circuit 260 are stopped from the turn-off circuit 270.

  When lighting the lighting device 200, the lighting device 200 turns on a switch (not shown) provided between the power supply system 210 and the rectifying circuit 220. Thereby, AC power is supplied from the commercial power supply to the rectifier circuit.

  The rectifier circuit 220 converts AC power into DC power. The voltage output from the rectifier circuit 220 is applied to the resistor R1 and the resistor R2 of the starting circuit 290. The voltage divided by the resistor R1 and the resistor R2 is applied to the base of the transistor Tr3 of the step-down circuit 240. The transistor Tr3 turns on the current path by the voltage applied to the base.

  Thereby, the electric current output from the rectifier circuit 220 flows into the reactor L5. Reactor L6 receives the magnetic flux generated by the current flowing through reactor L5, generates electric power, and supplies it to the secondary side of step-down circuit 240. As a result, the LED 280 is turned on.

  Reactor L7 receives magnetic flux generated by current flowing through reactor L5, generates electric power, and supplies the electric power to boost control circuit 250. Reactor L8 receives the magnetic flux generated by the current flowing through reactor L5, generates electric power, and supplies the electric power to step-down control circuit 260. Thereby, the step-up control circuit 250 and the step-down control circuit 260 operate. As a result, the booster circuit 230 and the step-down circuit 240 start normal operation.

  In the above-described embodiment, the configuration has been described in which the extinguishing circuit 170 stops the operation of the step-down circuit 140 by inputting the extinguishing signal to the step-down control circuit 160. However, the present invention is not limited to this configuration. The step-down circuit 140 may be stopped using a control signal output from the turn-off circuit 170.

  FIG. 3 is an explanatory diagram for describing a configuration example of a lighting apparatus 100 according to another embodiment of the present invention. In addition, the same reference is given to the same structure as the structure shown in FIG. 1, and detailed description is abbreviate | omitted.

  The illumination device 100 illustrated in FIG. 3 includes a transistor Tr4 between the base of the transistor Tr2 and the emitter of the transistor Tr2. The base of the transistor Tr2 is connected to the collector of the transistor Tr4. The emitter of the transistor Tr4 is connected to the emitter of the transistor Tr2. The base of the transistor Tr4 is connected to the extinguishing circuit 170.

  The turn-off circuit 170 outputs a turn-off signal to the base of the transistor Tr4. The transistor Tr4 turns on the current path between the collector and the emitter when a turn-off signal is input to the base. When the current path between the collector and the emitter is turned ON, the base of the transistor Tr2 is short-circuited, so that the transistor Tr2 is turned OFF. As a result, since the control signal input from the step-down control circuit 160 to the transistor Tr2 is not input, the operation of the step-down circuit 140 is stopped.

  That is, the extinguishing circuit 170 can turn off the transistor Tr2 and stop the step-down circuit 140 by turning on the transistor Tr4. Thereby, the turn-off circuit 170 can stop the step-down circuit 140 and the step-up circuit 130 together. According to this configuration, since the operation of the step-down circuit 140 can be stopped by the turn-off circuit 170, the step-down control circuit 160 can be simplified.

  Note that the emitter of the transistor Tr4 is described as being connected to the emitter of the transistor Tr2, but is not limited to this configuration. The emitter of the transistor Tr4 may be connected to any location other than the base of the transistor Tr2. For example, the emitter of the transistor Tr4 may be connected to GND.

  In addition, this invention is not limited to the said embodiment as it is, It can implement by changing a component in the range which does not deviate from the summary in an implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine the component covering different embodiment suitably.

  DESCRIPTION OF SYMBOLS 100 ... Illuminating device, 110 ... Power system, 120 ... Rectifier circuit, 130 ... Boost circuit, 140 ... Step-down circuit, 150 ... Step-up control circuit, 160 ... Step-down control circuit, 170 ... Light-off circuit, 180 ... LED, 190 ... Start circuit .

Claims (3)

DC power generation means;
Boosting means for boosting the power supply voltage supplied by the DC power generating means;
Boost control means for controlling the operation of the boost means;
Step-down means for stepping down the voltage boosted by the step-up means;
Step-down control means for controlling the operation of the step-down means and for controlling the current flowing in the semiconductor light emitting element;
Power supply means for supplying power from the output of the step-down means to the step-up control means;
An extinguishing means for stopping the output of the step-down means when the turn-off signal is input;
A power supply circuit comprising:   Characterized in that it comprises start means for starting supply of power to the boost control means by supplying DC power generated by the DC power generation means to the step-down means and starting the step-down means. The power supply circuit according to claim 1. A semiconductor light emitting device;
A power supply circuit according to claim 1 or 2;
An instrument body provided with the power supply circuit;
An illumination device comprising:

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