JP2007329996A - Switching power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switching power supply device which can prevent an increase in manufacturing cost and the enlargement of a circuit scale in order to cope with power consumption at starting. <P>SOLUTION: The switching power supply device includes: a PFC circuit 1 which includes a switching element Q1 and converts an input AC voltage into a DC voltage by the switching operation of the switching element Q1; a DC-DC converter circuit 52 which boosts the converted DC voltage and feeds it to a load; a PFC control circuit 5 which switch-controls the switching element Q1; a PFC starting power supply circuit 3 which is started by outputting a voltage to the PFC control circuit 5 on the basis of the input AC voltage; a PFC auxiliary power supply circuit 2 which outputs a voltage to the PFC control circuit 5 after the switching control of the switching element Q1 is started; and a PFC starting power supply stop circuit 4 which stops a voltage output of the PFC starting power supply circuit 3 after the lapse of a prescribed time after the PFC auxiliary power supply circuit 2 starts the voltage output. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a switching power supply device, and more particularly to a switching power supply device using a harmonic-compatible PFC circuit.

  An active clamp PFC (Power Factor Correction) circuit that achieves high efficiency and high power factor is used as a harmonic countermeasure for switching power supply devices. A control IC (Integrated Circuit) for controlling the PFC circuit is provided by each manufacturer.

  In the switching power supply device, a control IC using a CMOS process and having a standby current of about 1 mA is used. The starting circuit of the control IC can be composed of, for example, a resistor and an electrolytic capacitor, and it is sufficient to use an electrolytic capacitor having a capacity of about 100 μF. However, some control ICs use a bipolar process and consume a current of about 25 mA at startup. In this case, an electrolytic capacitor having a capacity of 2000 μF or more is required for starting the control IC, and the start-up time is increased and is not practical. However, if there is only this type of control IC that meets the required specifications at low cost, it is necessary to supply current to the control IC from a voltage obtained by rectifying and smoothing the input AC voltage, for example.

For example, Patent Document 1 discloses the following switching power supply device that employs such a configuration. That is, a power factor correction converter that controls on / off of the first switching element to convert it to a DC voltage higher than the AC voltage, and a DC voltage from the power factor correction converter that controls the second switching element on / off to another DC voltage. A switching power supply apparatus including a DC-DC converter for converting, a load state determination circuit for determining a load state based on a pulse signal for controlling on / off of the second switching element, and a predetermined load state by the load state determination circuit The operation of the power factor correction converter is stopped when it is determined that the lighter load is lighter, while the operation of the power factor correction converter is performed when it is determined that the load is heavier than the predetermined load. And a PFC on / off switching circuit to be activated.
JP 2003-169478 A

  Incidentally, the switching power supply device described in Patent Document 1 includes a resistor for supplying an operating current to a control IC from a voltage obtained by rectifying and smoothing an input AC voltage. Here, when the current consumption at the start-up of the control IC is 25 mA as described above, a resistance of about 5.6 kΩ is required for an AC input voltage of 100 V AC, and the power consumption is about 25 W. For this reason, the oxygold resistance or cement resistance corresponding to the power consumption of 5 W or less that is normally used cannot be used, and the manufacturing cost and circuit scale of the switching power supply device increase. That is, the switching power supply device described in Patent Document 1 has a problem that the manufacturing cost and the circuit scale increase in order to cope with the power consumption at the time of startup.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a switching power supply apparatus that can prevent an increase in manufacturing cost and circuit scale in order to cope with power consumption at startup.

  In order to solve the above problems, a switching power supply device according to an aspect of the present invention includes a switching element, a PFC circuit that converts an input AC voltage into a DC voltage by a switching operation of the switching element, and the converted DC voltage. A DC-DC converter circuit that boosts and supplies a load to a load, a PFC control circuit that performs switching control of switching elements, and a PFC that activates the PFC control circuit by outputting a voltage to the PFC control circuit based on an input AC voltage After the start-up power supply circuit and switching control of the switching element by the PFC control circuit are started, a PFC auxiliary power supply circuit that outputs a voltage to the PFC control circuit, and a predetermined time after the PFC auxiliary power supply circuit starts voltage output PFC start-up power supply stop circuit for stopping voltage output of PFC start-up power supply circuit .

  Preferably, the PFC auxiliary power supply circuit outputs a voltage to the PFC control circuit and the PFC start power supply stop circuit after the switching control of the switching element by the PFC control circuit is started, and the PFC start power supply stop circuit is input to the control electrode. Transistor for switching whether to stop the voltage output of the PFC start-up power supply circuit based on the applied voltage, a resistor, a capacitor, a Zener disposed between the PFC auxiliary power supply circuit and the resistor and between the PFC auxiliary power supply circuit and the capacitor The voltage output from the PFC start-up power supply stop circuit including the diode passes through the Zener diode, and is input to the control electrode of the transistor after being delayed by a time constant determined by the resistance value of the resistor and the capacitance value of the capacitor. .

  Preferably, the DC-DC converter circuit further outputs a voltage to the PFC start power supply stop circuit after the switching control of the switching element by the PFC control circuit is started, and the PFC start power supply stop circuit is input to the control electrode. The voltage output from the DC-DC converter circuit includes a transistor that switches whether or not to stop the voltage output of the PFC start-up power supply circuit based on the voltage to be output, a resistor, and a capacitor. The signal is delayed by a time constant determined by the capacitance value and input to the control electrode of the transistor.

  More preferably, the PFC start-up power supply stop circuit further includes a Zener diode disposed between the PFC start-up power supply stop circuit and the resistor and between the PFC start-up power supply stop circuit and the capacitor, and the voltage output from the DC-DC converter circuit is Then, the signal passes through the Zener diode, and is delayed by a time constant determined by the resistance value of the resistor and the capacitance value of the capacitor, and input to the control electrode of the transistor.

  Preferably, the DC-DC converter circuit includes a light emitting element that emits light when a boosted DC voltage becomes a predetermined value or more, and the PFC start-up power supply stop circuit depends on whether or not the light emitting element emits light. By switching between the on state and the off state, whether or not to stop the voltage output of the PFC start-up power supply circuit is switched.

  Preferably, the PFC auxiliary power supply circuit outputs a voltage to the PFC control circuit and the PFC start power supply stop circuit after the switching control of the switching element by the PFC control circuit is started, and outputs the voltage to the PFC control circuit and the PFC start power supply stop circuit. The stabilization circuit includes a stabilization circuit that stabilizes the output voltage. The stabilization circuit includes a resistor to which the output voltage is applied at one end, a Zener diode, one conductive electrode connected to one end of the resistor, and the control electrode to the other resistor. And a transistor to which a voltage is output from the other conductive electrode to the PFC control circuit and the PFC start-up power supply stop circuit.

  A switching power supply apparatus according to still another aspect of the present invention includes a switching element, a PFC circuit that converts an input AC voltage into a DC voltage by switching operation of the switching element, and boosts the converted DC voltage to a load. A DC-DC converter circuit to be supplied, a PFC control circuit that performs switching control of switching elements, and a PFC activation power supply circuit that activates the PFC control circuit by outputting a voltage to the PFC control circuit based on an input AC voltage The DC-DC converter circuit outputs a voltage to the PFC control circuit after switching control of the switching element by the PFC control circuit is started, and the switching power supply further includes the DC-DC converter circuit to the PFC control circuit. PFC start-up power supply circuit after a predetermined time has elapsed since the start of voltage output And a PFC startup power stop circuit for stopping the voltage output.

  Preferably, the DC-DC converter circuit outputs a voltage to the PFC control circuit and the PFC start power supply stop circuit after the switching control of the switching element by the PFC control circuit is started, and the PFC start power supply stop circuit is connected to the control electrode. A transistor, a resistor, a capacitor, a DC-DC converter circuit and a resistor, and a DC-DC converter circuit and a capacitor are arranged to switch whether or not to stop the voltage output of the PFC starting power supply circuit based on the input voltage. The voltage output from the DC-DC converter circuit passes through the Zener diode and is input to the control electrode of the transistor after being delayed by a time constant determined by the resistance value of the resistor and the capacitance value of the capacitor. Is done.

  Preferably, the DC-DC converter circuit outputs a voltage to the PFC control circuit and the PFC start power supply stop circuit after the switching control of the switching element by the PFC control circuit is started, and to the PFC control circuit and the PFC start power supply stop circuit. A stabilization circuit for stabilizing the output voltage of the output circuit, the stabilization circuit including a resistor to which the output voltage is applied at one end, a Zener diode, one conduction electrode connected to one end of the resistor, and a control electrode having a resistance The other end is connected to one end of a Zener diode, and includes a transistor that outputs a voltage from the other conductive electrode to the PFC control circuit and the PFC start-up power supply stop circuit.

  Preferably, the DC-DC converter circuit includes a light emitting element that emits light when a boosted DC voltage becomes a predetermined value or more, and the PFC start-up power supply stop circuit depends on whether or not the light emitting element emits light. By switching between the on state and the off state, whether or not to stop the voltage output of the PFC start-up power supply circuit is switched.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that a manufacturing cost and a circuit scale increase in order to respond to the power consumption at the time of starting.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<First Embodiment>
FIG. 1 is a circuit diagram showing a configuration of a switching power supply apparatus according to the first embodiment of the present invention.

  Referring to FIG. 2, this switching power supply device includes a PFC unit 51, a DC-DC converter unit (DC-DC converter circuit) 52, input terminals TIN1 and TIN2, and output terminals TOUT1 and TOUT2. The PFC unit 51 includes a bridge diode BD1, a capacitor C1, a PFC circuit 1, a PFC auxiliary power circuit 2, a PFC start power circuit 3, a PFC start power stop circuit 4, a PFC control circuit 5, and a detection circuit 6. Including. The DC-DC converter unit 52 includes a DC-DC auxiliary power supply circuit 11, a voltage detection circuit 12, a primary side control circuit 13, a primary-secondary transmission circuit 14, a transformer T1, a transistor Q4, and a capacitor. C6 and diode D2 are included.

  The PFC circuit 1 includes a transistor (switching element) Q1, a choke coil L1, a diode D1, and a capacitor C2. PFC auxiliary power circuit 2 includes a coil (auxiliary winding) L2, diodes D3 and D5, and a capacitor C3. PFC activation power supply circuit 3 includes a choke coil L1, a diode D1, resistors R1 and R2, a transistor Q2, a diode D4, and a Zener diode ZD1. PFC start-up power supply stop circuit 4 includes resistors R3 to R5, a capacitor C4, and a transistor Q3. Detection circuit 6 includes resistors R6 and R7. For example, transistors Q1, Q2 and Q4 are MOSFETs, and transistor Q3 is a bipolar transistor.

  Input terminals TIN1 and TIN2 are connected to corresponding input terminals of bridge diode BD1, respectively. One output terminal of the bridge diode BD1, one end of the capacitor C1, and one end of the choke coil L1 are connected. The other end of the choke coil L1, the anode of the diode D1, and the drain of the transistor Q1 are connected. The gate of the transistor Q1 is connected to the output of the PFC control circuit 5. The cathode of diode D1, the positive electrode of capacitor C2, one end of resistor R6, and one end of resistors R1 and R2 are connected. The other end of the resistor R6, one end of the resistor R7, and the input of the PFC control circuit 5 are connected. That is, the voltage detection result of the detection circuit 6 is output to the PFC control circuit 5.

  The transistor Q2 has a drain connected to the other end of the resistor R1, a source (conducting electrode) connected to the anode of the diode D4, a gate connected to the other end of the resistor R2, the cathode of the Zener diode ZD1, and the collector of the transistor Q3 ( Conductive electrode). The cathode of the diode D4, the cathode of the diode D5, and the input of the PFC control circuit 5 are connected. The base (control electrode) of transistor Q3, one end of resistor R4, and one end of resistor R5 are connected.

  The anode of diode D5, the cathode of diode D3, one end of resistor R3, and the positive electrode of capacitor C3 are connected. The other end of the resistor R3, the other end of the resistor R5, and one end of the capacitor C4 are connected. The anode of diode D3 and one end of coil L2 are connected.

  One end of the winding L11 is connected to one end of the resistor R6. The transistor Q4 has a drain connected to the other end of the winding L11 and a gate connected to the output of the primary side control circuit 13. The DC-DC auxiliary power supply circuit 11 has an input connected to one end of the winding L <b> 13 and an output connected to the input of the primary side control circuit 13.

  The anode of the diode D2 is connected to one end of the winding L12, and the cathode is connected to the positive electrode of the capacitor C6, the input of the voltage detection unit 12, and the output terminal TOUT1. The negative electrode of capacitor C6, the other end of winding L12, and output terminal TOUT2 are connected. The voltage detection result of the voltage detector 12 is output to the primary side control circuit 13 via the primary-secondary transmission circuit 14.

  The other output terminal of the bridge diode BD1, the other end of the capacitor C1, the anode of the Zener diode ZD1, the emitter (conduction electrode) of the transistor Q3, the other end of the resistor R4, the other end of the capacitor C4, and the capacitor C3 The negative electrode, the other end of the coil L2, the source of the transistor Q1, the negative electrode of the capacitor C2, the other end of the resistor R7, the source of the transistor Q4, and the other end of the winding L13 are at a common connection point. Connected.

  The PFC activation power supply circuit 3 outputs a voltage to the PFC control circuit 5 based on the input AC voltage, and activates the PFC control circuit 5. More specifically, the AC voltage supplied from the outside to the input terminals TIN1 and TIN2 is full-wave rectified by the bridge diode BD1. The voltage output from the bridge diode BD1 is rectified and smoothed by the choke coil L1, the diode D1, and the capacitor C2, and becomes a DC voltage. The DC voltage is supplied to the PFC control circuit 5 through the resistor R1, the drain and source of the transistor Q2, and the diode D4.

  When power is supplied from the PFC activation power supply circuit 3, the PFC control circuit 5 outputs a control voltage to the base of the transistor Q1 in the PFC circuit 1 based on the voltage detection result of the detection circuit 6, and controls switching of the transistor Q1. To do. More specifically, the PFC control circuit 5 switches the on-state and off-state of the transistor Q1, boosts the voltage that has been full-wave rectified by the bridge diode BD1, and converts the voltage into a direct-current voltage. To the unit 52. Here, the DC voltage boosted by the PFC control circuit 5 has a higher voltage value than the AC voltage input from the outside. The PFC control circuit 5 switches the transistor Q1 between the on state and the off state so that the voltage value detected by the detection circuit 6 is constant.

  The DC-DC converter unit 52 boosts the DC voltage received from the PFC circuit 1 and outputs the boosted voltage to the outside.

  The PFC auxiliary power supply circuit 2 outputs a voltage to the PFC control circuit 5 and the PFC activation power supply stop circuit 4 after the switching control of the PFC control circuit 5 is started. The PFC activation power supply stop circuit 4 stops the voltage output of the PFC activation power supply circuit 3 after a predetermined time has elapsed since the PFC auxiliary power supply circuit 2 started voltage output.

  More specifically, a voltage is induced in the coil (auxiliary winding) L2 magnetically coupled to the choke coil L1 by the switching operation of the transistor Q1. The voltage induced in the coil L2 is rectified and smoothed by the diode D3 and the capacitor C3, and is supplied to the PFC control circuit 5 via the diode D5.

  The induced voltage rectified and smoothed by the diode D3 and the capacitor C3 is delayed by a time constant determined by the resistance value of the resistor R3 and the capacitance of the capacitor C4, and supplied to the base of the transistor Q3 via the resistor R5. Then, since the transistor Q3 is turned on, the voltage across the Zener diode ZD1 becomes 0V, and the transistor Q2 is turned off. When the transistor Q2 is turned off, voltage output from the PFC activation power supply circuit 3 to the PFC control circuit 5 is stopped. That is, the transistor Q3 switches whether to stop the voltage output of the PFC activation power supply circuit 2 based on the voltage input to the base (control electrode).

  Incidentally, the switching power supply device described in Patent Document 1 has a problem that the manufacturing cost and the circuit scale increase in order to cope with the power consumption at the time of startup. However, in the switching power supply device according to the first embodiment of the present invention, the PFC auxiliary power supply circuit 2 outputs a voltage to the PFC control circuit 5 after the switching control of the PFC control circuit 5 is started. Then, the PFC activation power supply stop circuit 4 stops the voltage output of the PFC activation power supply circuit 3 after the PFC auxiliary power supply circuit 2 starts voltage output. Therefore, the power supply circuit can be switched when the PFC control circuit 5, that is, the PFC circuit 1 is started and after the start-up, and the manufacturing cost and the circuit scale can be prevented from increasing in order to cope with the power consumption at the start-up.

  Here, in the configuration in which the PFC start-up power supply stop circuit 4 immediately stops the voltage output of the PFC start-up power supply circuit 3 in response to the voltage induced in the coil (auxiliary winding) L2, the PFC circuit 1 and the subsequent DC-DC While the operation of the converter unit 52 is not stable, the voltage output of the PFC starting power supply circuit 3 may stop and the switching power supply device may fail to start. However, in the switching power supply according to the first embodiment of the present invention, the PFC start-up power supply stop circuit 4 includes the voltage of the PFC start-up power supply circuit 3 after a predetermined time has elapsed since the PFC auxiliary power supply circuit 2 started voltage output. Stop output. Therefore, the voltage can be output from the PFC activation power supply circuit 3 to the PFC control circuit 5 until the output voltages of the PFC circuit 1 and the DC-DC converter unit 52 at the subsequent stage are stabilized, and the switching power supply device can be activated reliably. it can.

  Further, since the PFC activation power supply circuit 3 includes the Zener diode ZD1, a Zener voltage is applied to the gate of the transistor Q2, and the source voltage of the transistor Q2 is changed from the Zener voltage to the threshold voltage of the transistor Q2, that is, the transistor Q2 is turned on. This is a constant voltage obtained by subtracting the gate voltage. With such a configuration, it is possible to prevent an excessive voltage from being applied to the PFC control circuit 5 and being destroyed.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Second Embodiment>
The present embodiment relates to a switching power supply device in which the configuration of the PFC activation power supply stop circuit is changed as compared with the switching power supply device according to the first embodiment.

  FIG. 2 is a circuit diagram showing a configuration of a switching power supply apparatus according to the second embodiment of the present invention. Referring to FIG. 2, in this switching power supply device, as compared with the switching power supply device according to the first embodiment, PFC activation power supply stop circuit 4 further includes a Zener diode ZD2.

  The anode of the diode D5, the cathode of the diode D3, the cathode of the Zener diode ZD2, and the positive electrode of the capacitor C3 are connected. The anode of the Zener diode ZD2 and one end of the resistor R3 are connected.

  When the capacitance value of the capacitor C4 is large, it takes a long time to discharge the capacitor C4. In this case, if the switching power supply device is rapidly started and stopped, electric charge tends to remain in the capacitor C4, and the timing at which the induced voltage rectified and smoothed by the diode D3 and the capacitor C3 is supplied to the base of the transistor Q3 is delayed. It may cause malfunction of the power supply.

  However, in the switching power supply according to the second embodiment of the present invention, the PFC start-up power supply stop circuit 4 includes the Zener diode ZD2, so that the Zener voltage of the Zener diode ZD2 is smaller than the voltage induced by the coil L2. Since the voltage is supplied to the resistor R3 and the capacitor C4, the capacitance of the capacitor C4 can be reduced, and malfunction of the switching power supply device can be prevented.

  Other configurations and operations are the same as those of the switching power supply according to the first embodiment. Therefore, in the switching power supply according to the second embodiment of the present invention, like the switching power supply according to the first embodiment, the manufacturing cost and the circuit scale increase in order to cope with the power consumption at startup. Can be prevented.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Third Embodiment>
The present embodiment relates to a switching power supply apparatus in which the configuration for stopping the voltage output of the PFC activation power supply circuit is changed as compared with the switching power supply apparatus according to the first embodiment.

  FIG. 3 is a circuit diagram showing a configuration of a switching power supply apparatus according to the third embodiment of the present invention. Referring to FIG. 3, DC-DC auxiliary power circuit 11 includes a capacitor C5 and a diode D6.

  In the DC-DC auxiliary power circuit 11, the diode D6 has an anode connected to one end of the winding L13, and a cathode connected to the positive electrode of the capacitor C5, the input of the primary side control circuit 13, and one end of the resistor R3. Is done. The negative electrode of the capacitor C5 is connected to the other end of the winding L13.

  The DC-DC auxiliary power supply circuit 11 outputs a voltage to the PFC activation power supply stop circuit 4 after the switching control of the PFC control circuit 5 is started. The PFC start-up power supply stop circuit 4 stops the voltage output of the PFC start-up power supply circuit 3 after a predetermined time has elapsed since the DC-DC auxiliary power supply circuit 11 started voltage output.

  More specifically, a voltage is induced in winding L13 by the switching operation of transistors Q1 and Q4. The voltage induced in the winding L13 is delayed by a time constant determined by the resistance value of the resistor R3 and the capacitance of the capacitor C4, and supplied to the base of the transistor Q3 via the resistor R5. Then, since the transistor Q3 is turned on, the voltage across the Zener diode ZD1 becomes 0V, and the transistor Q2 is turned off. When the transistor Q2 is turned off, voltage output from the PFC activation power supply circuit 3 to the PFC control circuit 5 is stopped. That is, the transistor Q3 switches whether to stop the voltage output of the PFC activation power supply circuit 2 based on the voltage input to the base (control electrode).

  Other configurations and operations are the same as those of the switching power supply according to the first embodiment. Therefore, in the switching power supply according to the third embodiment of the present invention, like the switching power supply according to the first embodiment, the manufacturing cost and the circuit scale increase in order to cope with the power consumption at the time of startup. Can be prevented.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Fourth embodiment>
The present embodiment relates to a switching power supply apparatus in which the configuration of the PFC start-up power supply stop circuit is changed as compared with the switching power supply apparatus according to the third embodiment.

  FIG. 4 is a circuit diagram showing a configuration of a switching power supply apparatus according to the fourth embodiment of the present invention. Referring to FIG. 4, in this switching power supply device, as compared with the switching power supply device according to the third embodiment, PFC activation power supply stop circuit 4 further includes a Zener diode ZD2.

  Other configurations and operations are the same as those of the switching power supply according to the third embodiment.

  Therefore, in the switching power supply according to the fourth embodiment of the present invention, like the switching power supply according to the first embodiment, the manufacturing cost and the circuit scale increase in order to cope with the power consumption at the time of startup. Can be prevented.

  Further, in the switching power supply device according to the fourth embodiment of the present invention, the capacitance of the capacitor C4 can be reduced similarly to the switching power supply device according to the second embodiment. Malfunctions can be prevented.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Fifth embodiment>
The present embodiment relates to a switching power supply device in which the configuration of the PFC activation power supply stop circuit is changed as compared with the switching power supply device according to the first embodiment.

  FIG. 5 is a circuit diagram showing a configuration of a switching power supply apparatus according to the fifth embodiment of the present invention. Referring to FIG. 5, in this switching power supply device, as compared with the switching power supply device according to the first embodiment, DC-DC converter unit 52 includes photocoupler diode (light emitting element) PC1-DI, resistance R10 and capacitor C7 are included. Further, the PFC start-up power supply stop circuit 4 includes a photocoupler transistor (light receiving element) PC1-TR.

  The anode of photocoupler diode PC1-DI, one end of capacitor C7, and one end of resistor R10 are connected. The other end of the resistor R10, the output terminal TOUT1, the cathode of the diode D2, the input of the voltage detection unit 12, and the positive electrode of the capacitor C6 are connected. The cathode of the photocoupler diode PC1-DI, the other end of the capacitor C7, the output terminal TOUT2, and the other end of the winding L12 are connected. One conduction electrode of photocoupler transistor PC1-TR, the base of transistor Q2, the other end of resistor R2, and the cathode of Zener diode ZD1 are connected. The other conduction electrode of photocoupler transistor PC1-TR is connected to the anode of Zener diode ZD1.

  A voltage is induced in the winding L12 by the switching operation of the transistors Q1 and Q4. When the voltage induced in the winding L12 exceeds a predetermined value, a current flows through the photocoupler diode PC1-DI to emit light. Then, since the photocoupler transistor PC1-TR is turned on, the voltage across the Zener diode ZD1 becomes 0V, and the transistor Q2 is turned off. When the transistor Q2 is turned off, voltage output from the PFC activation power supply circuit 3 to the PFC control circuit 5 is stopped. That is, the photocoupler transistor PC1-TR determines whether to stop the voltage output of the PFC start-up power supply circuit 2 by switching between the on state and the off state according to whether the photocoupler diode PC1-DI emits light. Switch. Further, by adjusting the capacitance value of the capacitor C7, it is possible to adjust the time constant, that is, the timing at which the photocoupler diode PC1-DI emits light.

  Other configurations and operations are the same as those of the switching power supply according to the first embodiment. Therefore, in the switching power supply according to the fifth embodiment of the present invention, like the switching power supply according to the first embodiment, the manufacturing cost and the circuit scale increase in order to cope with the power consumption at startup. Can be prevented.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Sixth Embodiment>
The present embodiment relates to a switching power supply device in which the configuration of the PFC auxiliary power supply circuit is changed as compared with the switching power supply device according to the second embodiment.

  FIG. 6 is a circuit diagram showing a configuration of a switching power supply apparatus according to the sixth embodiment of the present invention. Referring to FIG. 6, in this switching power supply device, PFC auxiliary power supply circuit 2 further includes a stabilization circuit 15 as compared with the switching power supply device according to the second embodiment. Stabilization circuit 15 includes a transistor Q5, a resistor R8, and a Zener diode ZD3.

  The cathode of diode D3, the source of transistor Q5, one end of resistor R8, and the positive electrode of capacitor C3 are connected. The base of transistor Q5, the other end of resistor R8, and the cathode of Zener diode ZD3 are connected. The drain of transistor Q5, the anode of diode D5, and the cathode of Zener diode ZD2 are connected. The anode of Zener diode ZD3, the negative electrode of capacitor C3, and the other end of capacitor C4 are connected.

  The stabilization circuit 15 stabilizes the voltage induced in the auxiliary winding L2, that is, the supply voltage to the PFC control circuit 5 and the PFC start-up power supply stop circuit 4. With this configuration, the operation of the switching power supply device can be stabilized.

  Other configurations and operations are the same as those of the switching power supply according to the second embodiment. Therefore, in the switching power supply according to the sixth embodiment of the present invention, like the switching power supply according to the second embodiment, the manufacturing cost and the circuit scale increase in order to cope with the power consumption at the start-up. Can be prevented. In addition, the capacitance of the capacitor C4 can be reduced, and malfunction of the switching power supply device can be prevented.

<Seventh embodiment>
The present embodiment relates to a switching power supply device in which a PFC auxiliary power supply circuit is substituted with an auxiliary power supply circuit, as compared with the switching power supply device according to the third embodiment.

  FIG. 7 is a circuit diagram showing a configuration of a switching power supply apparatus according to the seventh embodiment of the present invention.

  Referring to FIG. 7, this switching power supply device does not include PFC auxiliary power supply circuit 2, and DC-DC auxiliary power supply circuit 11 further includes a diode D5.

  The anode of the diode D5, one end of the resistor R3, the cathode of the diode D6 in the DC-DC auxiliary power supply circuit 11, and one end of the capacitor C5 are connected.

  The DC-DC auxiliary power supply circuit 11 outputs a voltage to the PFC control circuit 5 and the PFC activation power supply stop circuit 4 after the switching control of the PFC control circuit 5 is started. The PFC start-up power supply stop circuit 4 stops the voltage output of the PFC start-up power supply circuit 3 after a predetermined time has elapsed since the DC-DC auxiliary power supply circuit 11 started voltage output.

  More specifically, a voltage is induced in winding L13 by the switching operation of transistors Q1 and Q4. The voltage induced in the winding L13 is supplied to the PFC control circuit 5 through the diode D5. Further, the voltage induced in the winding L13 is delayed by a time constant determined by the resistance value of the resistor R3 and the capacitance of the capacitor C4, and is supplied to the base of the transistor Q3 via the resistor R5.

  Other configurations and operations are the same as those of the switching power supply according to the third embodiment. Therefore, in the switching power supply according to the seventh embodiment of the present invention, like the switching power supply according to the third embodiment, the manufacturing cost and the circuit scale increase in order to cope with the power consumption at startup. Can be prevented.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Eighth Embodiment>
The present embodiment relates to a switching power supply device in which the configuration of the PFC start-up power supply stop circuit is changed as compared with the switching power supply device according to the seventh embodiment.

  FIG. 8 is a circuit diagram showing a configuration of a switching power supply apparatus according to the eighth embodiment of the present invention. Referring to FIG. 8, in this switching power supply device, as compared with the switching power supply device according to the fifth embodiment, PFC activation power supply stop circuit 4 further includes a Zener diode ZD2.

  Other configurations and operations are the same as those of the switching power supply according to the seventh embodiment.

  Therefore, in the switching power supply according to the eighth embodiment of the present invention, like the switching power supply according to the first embodiment, the manufacturing cost and the circuit scale increase in order to cope with the power consumption at the start-up. Can be prevented.

  Further, in the switching power supply according to the eighth embodiment of the present invention, the capacitance of the capacitor C4 can be reduced as in the switching power supply according to the second embodiment. Malfunctions can be prevented.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Ninth embodiment>
The present embodiment relates to a switching power supply device in which the configuration of the auxiliary power supply circuit is changed as compared with the switching power supply device according to the eighth embodiment.

  FIG. 9 is a circuit diagram showing a configuration of a switching power supply according to the ninth embodiment of the present invention. Referring to FIG. 9, in this switching power supply device, DC-DC auxiliary power supply circuit 11 further includes a stabilization circuit 16 as compared with the switching power supply device according to the sixth embodiment. Stabilization circuit 16 includes a transistor Q6, a resistor R9, and a Zener diode ZD4.

  In the DC-DC auxiliary power circuit 11, the diode D6 has an anode connected to one end of the winding L13, and a cathode connected to the positive electrode of the capacitor C5, one end of the resistor R9, and the drain of the transistor Q6. The base of transistor Q5, the other end of resistor R9, and the cathode of Zener diode ZD4 are connected. The source of the transistor Q5, the input of the primary side control circuit 13, the cathode of the Zener diode ZD2, and the anode of the diode D5 are connected. The anode of Zener diode ZD4, the negative electrode of capacitor C5, and the other end of winding L13 are connected.

  The stabilization circuit 16 stabilizes the voltage induced in the auxiliary winding L13, that is, the supply voltage to the PFC control circuit 5 and the PFC start-up power supply stop circuit 4. With this configuration, the operation of the switching power supply device can be stabilized.

  Other configurations and operations are the same as those of the switching power supply according to the eighth embodiment. Therefore, in the switching power supply according to the ninth embodiment of the present invention, like the switching power supply according to the eighth embodiment, the manufacturing cost and the circuit scale increase in order to cope with the power consumption at the start-up. Can be prevented. In addition, the capacitance of the capacitor C4 can be reduced, and malfunction of the switching power supply device can be prevented.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Tenth Embodiment>
The present embodiment relates to a switching power supply device in which a PFC auxiliary power supply circuit is substituted with an auxiliary power supply circuit as compared with the switching power supply device according to the seventh embodiment.

  FIG. 10 is a circuit diagram showing the configuration of the switching power supply according to the tenth embodiment of the present invention. Referring to FIG. 10, in this switching power supply device, as compared with the switching power supply device according to the seventh embodiment, DC-DC converter unit 52 includes photocoupler diode (light emitting element) PC1-DI, resistance R10 and capacitor C7 are included. Further, the PFC start-up power supply stop circuit 4 includes a photocoupler transistor (light receiving element) PC1-TR.

  The anode of photocoupler diode PC1-DI, one end of capacitor C7, and one end of resistor R10 are connected. The other end of the resistor R10, the output terminal TOUT1, the cathode of the diode D2, the input of the voltage detection unit 12, and the positive electrode of the capacitor C6 are connected. The cathode of the photocoupler diode PC1-DI, the other end of the capacitor C7, the output terminal TOUT2, and the other end of the winding L12 are connected. One conduction electrode of photocoupler transistor PC1-TR, the base of transistor Q2, the other end of resistor R2, and the cathode of Zener diode ZD1 are connected. The other conduction electrode of photocoupler transistor PC1-TR is connected to the anode of Zener diode ZD1.

  A voltage is induced in the winding L12 by the switching operation of the transistors Q1 and Q4. When the voltage induced in the winding L12 exceeds a predetermined value, a current flows through the photocoupler diode PC1-DI to emit light. Then, since the photocoupler transistor PC1-TR is turned on, the voltage across the Zener diode ZD1 becomes 0V, and the transistor Q2 is turned off. When the transistor Q2 is turned off, voltage output from the PFC activation power supply circuit 3 to the PFC control circuit 5 is stopped. That is, the photocoupler transistor PC1-TR determines whether to stop the voltage output of the PFC start-up power supply circuit 2 by switching between the on state and the off state according to whether the photocoupler diode PC1-DI emits light. Switch. Further, by adjusting the capacitance value of the capacitor C7, it is possible to adjust the time constant, that is, the timing at which the photocoupler diode PC1-DI emits light.

  Other configurations and operations are the same as those of the switching power supply according to the seventh embodiment. Therefore, in the switching power supply according to the tenth embodiment of the present invention, as with the switching power supply according to the seventh embodiment, the manufacturing cost and the circuit scale increase in order to cope with the power consumption at startup. Can be prevented.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a circuit diagram showing a configuration of a switching power supply device according to a first embodiment of the present invention. It is a circuit diagram which shows the structure of the switching power supply device which concerns on the 2nd Embodiment of this invention. It is a circuit diagram which shows the structure of the switching power supply device which concerns on the 3rd Embodiment of this invention. It is a circuit diagram which shows the structure of the switching power supply device which concerns on the 4th Embodiment of this invention. It is a circuit diagram which shows the structure of the switching power supply device which concerns on the 5th Embodiment of this invention. It is a circuit diagram which shows the structure of the switching power supply device which concerns on the 6th Embodiment of this invention. It is a circuit diagram which shows the structure of the switching power supply device which concerns on the 7th Embodiment of this invention. It is a circuit diagram which shows the structure of the switching power supply device which concerns on the 8th Embodiment of this invention. It is a circuit diagram which shows the structure of the switching power supply device which concerns on the 9th Embodiment of this invention. It is a circuit diagram which shows the structure of the switching power supply device which concerns on the 10th Embodiment of this invention.

Explanation of symbols

  1 PFC circuit, 2 PFC auxiliary power supply circuit, 3 PFC start power supply circuit, 4 PFC start power supply stop circuit, 5 PFC control circuit, 6 detection circuit, 11 DC-DC auxiliary power supply circuit, 12 voltage detection circuit, 13 primary side control Circuit, 14 primary-secondary transmission circuit, 15, 16 stabilization circuit, 51 PFC section, 52 DC-DC converter section (DC-DC converter circuit), TIN1, TIN2 input terminal, TOUT1, TOUT2 output terminal, BD1 bridge Diode, C1-C7 capacitor, D1-D6 diode, T1 transformer, Q1-Q6 transistor, L1 choke coil, L2 coil (auxiliary winding), ZD1-ZD4 Zener diode, R1-R10 resistor, PC1-DI photocoupler diode ( Light-emitting element), PC1-TR photocoupler Transistor (light receiving element).

Claims (10)

A PFC circuit that includes a switching element and converts an input AC voltage into a DC voltage by a switching operation of the switching element;
A DC-DC converter circuit that boosts the converted DC voltage and supplies it to a load;
A PFC control circuit for performing switching control of the switching element;
A PFC activation power supply circuit that activates the PFC control circuit by outputting a voltage to the PFC control circuit based on the input AC voltage;
A PFC auxiliary power circuit that outputs a voltage to the PFC control circuit after the switching control of the switching element by the PFC control circuit is started;
A switching power supply comprising: a PFC start power supply stop circuit that stops voltage output of the PFC start power supply circuit after a predetermined time has elapsed since the PFC auxiliary power supply circuit started voltage output. The PFC auxiliary power supply circuit outputs a voltage to the PFC control circuit and the PFC start-up power supply stop circuit after the switching control of the switching element by the PFC control circuit is started.
The PFC start-up power supply stop circuit is
A transistor for switching whether to stop the voltage output of the PFC start-up power supply circuit based on the voltage input to the control electrode;
Resistance,
A capacitor,
A Zener diode disposed between the PFC auxiliary power circuit and the resistor and between the PFC auxiliary power circuit and the capacitor;
The voltage output from the PFC start-up power supply stop circuit passes through the Zener diode, and is input to the control electrode of the transistor after being delayed by a time constant determined by the resistance value of the resistor and the capacitance value of the capacitor. The switching power supply device according to claim 1. The DC-DC converter circuit further outputs a voltage to the PFC start-up power supply stop circuit after the switching control of the switching element by the PFC control circuit is started,
The PFC start-up power supply stop circuit is
A transistor for switching whether to stop the voltage output of the PFC start-up power supply circuit based on the voltage input to the control electrode;
Resistance,
Including a capacitor,
2. The switching power supply according to claim 1, wherein the voltage output from the DC-DC converter circuit is input to the control electrode of the transistor after being delayed by a time constant determined by a resistance value of the resistor and a capacitance value of the capacitor. apparatus. The PFC start-up power supply stop circuit further includes a Zener diode disposed between the PFC start-up power supply stop circuit and the resistor and between the PFC start-up power supply stop circuit and the capacitor,
The voltage output from the DC-DC converter circuit passes through the Zener diode, and is input to the control electrode of the transistor after being delayed by a time constant determined by the resistance value of the resistor and the capacitance value of the capacitor. The switching power supply device according to claim 3. The DC-DC converter circuit includes a light emitting element that emits light when a boosted DC voltage becomes a predetermined value or more,
The said PFC starting power supply stop circuit switches whether the voltage output of the said PFC starting power supply circuit is stopped by switching an ON state and an OFF state according to whether the said light emitting element light-emits. Switching power supply. The PFC auxiliary power circuit is
After the switching control of the switching element by the PFC control circuit is started, a voltage is output to the PFC control circuit and the PFC start-up power supply stop circuit,
A stabilization circuit for stabilizing an output voltage to the PFC control circuit and the PFC start-up power supply stop circuit;
The stabilization circuit includes:
A resistor to which the output voltage is applied at one end;
Zener diode,
One end of the resistor is connected to one conducting electrode, the other end of the resistor and one end of the Zener diode are connected to the control electrode, and the other conducting electrode connects to the PFC control circuit and the PFC start-up power supply stop circuit. The switching power supply device according to claim 1, further comprising a transistor that outputs a voltage. A PFC circuit that includes a switching element and converts an input AC voltage into a DC voltage by a switching operation of the switching element;
A DC-DC converter circuit that boosts the converted DC voltage and supplies it to a load;
A PFC control circuit for performing switching control of the switching element;
A PFC activation power supply circuit that activates the PFC control circuit by outputting a voltage to the PFC control circuit based on the input AC voltage;
The DC-DC converter circuit outputs a voltage to the PFC control circuit after switching control of the switching element by the PFC control circuit is started.
The switching power supply device further includes:
A switching power supply device comprising: a PFC startup power supply stop circuit that stops the voltage output of the PFC startup power supply circuit after a predetermined time has elapsed since the DC-DC converter circuit started voltage output to the PFC control circuit. The DC-DC converter circuit outputs a voltage to the PFC control circuit and the PFC start-up power supply stop circuit after the switching control of the switching element by the PFC control circuit is started.
The PFC start-up power supply stop circuit is
A transistor for switching whether to stop the voltage output of the PFC start-up power supply circuit based on the voltage input to the control electrode;
Resistance,
A capacitor,
A Zener diode disposed between the DC-DC converter circuit and the resistor and between the DC-DC converter circuit and the capacitor;
The voltage output from the DC-DC converter circuit passes through the Zener diode, and is input to the control electrode of the transistor after being delayed by a time constant determined by the resistance value of the resistor and the capacitance value of the capacitor. The switching power supply device according to claim 7. The DC-DC converter circuit is
After the switching control of the switching element by the PFC control circuit is started, a voltage is output to the PFC control circuit and the PFC start-up power supply stop circuit,
A stabilization circuit for stabilizing an output voltage to the PFC control circuit and the PFC start-up power supply stop circuit;
The stabilization circuit includes:
A resistor to which the output voltage is applied at one end;
Zener diode,
One end of the resistor is connected to one conduction electrode, the other end of the resistor and one end of the Zener diode are connected to the control electrode, and the other conduction electrode connects to the PFC control circuit and the PFC start-up power supply stop circuit. The switching power supply device according to claim 7, further comprising a transistor that outputs a voltage. The DC-DC converter circuit includes a light emitting element that emits light when a boosted DC voltage becomes a predetermined value or more,
The said PFC starting power supply stop circuit switches whether the voltage output of the said PFC starting power supply circuit is stopped by switching an ON state and an OFF state according to whether the said light emitting element light-emits. Switching power supply.

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