JP2011135721A - Power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device that eliminates the need for a starting circuit for a power supply voltage supply circuit. <P>SOLUTION: The power supply device includes a rectifying/smoothing circuit 11 for converting an AC voltage into a DC voltage, an active filter 20 for stepping up the DC voltage outputted from the rectifying/smoothing circuit 11 to a prescribed DC voltage, an inverter 30 for converting the stepped-up DC voltage outputted from the active filter 20 into a high-frequency voltage so as to apply it to a discharge lamp 12, a control circuit 50 for controlling the inverter 30 on the basis of an external dimming signal, and a power supply voltage supply circuit 60 for supplying a power supply voltage to the control circuit 50. The power supply voltage supply circuit 60 is a power supply device that operates by receiving a voltage for a power supply voltage from the active filter 20. When the power supply is turned on, the control circuit 50 is operated after operating the active filter 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply apparatus including an active filter that boosts a DC voltage.

  2. Description of the Related Art Conventionally, a discharge lamp lighting device (power supply device) including an inverter that converts a DC voltage into low frequency power is known (see Patent Document 1).

  Such a discharge lamp lighting device includes an active filter that boosts an AC voltage and converts it into a DC voltage, a current limiting circuit that controls a current flowing through the discharge lamp, an inverter that converts a DC voltage from the active filter into low-frequency power, and And a start pulse generating circuit for applying a start pulse to the discharge lamp, a control circuit for controlling the start pulse generating circuit, and the like.

  Further, a discharge lamp lighting device shown in FIG. 2 has been proposed. The discharge lamp lighting device has a rectifying / smoothing circuit 1 for converting an AC voltage into a DC voltage, and a DC voltage output from the rectifying / smoothing circuit 1 is predetermined. An active filter 2 for boosting to a direct current voltage, an inverter 3 for converting the boosted direct current voltage output from the active filter 2 to a high frequency voltage and applying it to a load, and controlling the inverter 3 based on a dimming signal from the outside A control circuit 4 that performs power supply, a power supply voltage supply circuit 5 that supplies a power supply voltage to the control circuit 4, a startup circuit 6 that activates the power supply voltage supply circuit 5, and the like.

  In the discharge lamp lighting device, when the power is turned on, the capacitor C1 is charged through the resistor R1 of the starting circuit 6, and when the capacitor C1 reaches a predetermined voltage, the transistor Tr1 is turned on and a current flows through the starting resistor R2. The capacitor C2 is charged. Then, a predetermined voltage is generated by the dropper circuit of the transistor Tr2 and the Zener diode Zn3, and this predetermined voltage is supplied to the control circuit 4 to start the control circuit 4.

  When activated, the control circuit 4 cancels the operation inhibition applied to the active filter IC of the active filter 2, and thereby the active filter IC starts operation. By the operation of the active filter IC, the switch element Q1 is turned on / off to generate a voltage in the secondary coil Ta of the transformer T. This voltage is applied to the collector of the transistor Tr2 of the dropper circuit via the diode D1, the resistor R5, and the diode D2. To be supplied.

  Further, the control circuit 4 turns on the transistor Tr3 of the starter circuit 6 after the operation of the active filter IC is started, thereby turning on the Zener diode Zn2. As a result, the voltage at the gate of the transistor Tr1 becomes lower than the voltage supplied to the capacitor C2, the transistor Tr1 is turned off, and the starting resistor R2 is disconnected from the power supply voltage supply circuit 5.

  For this reason, after the activation of the active filter IC, the voltage is supplied from the secondary coil Ta of the transformer T to the power supply voltage supply circuit 5 without passing through the activation resistor R2. After the activation of the control circuit 4, the activation resistor R2 The prevention of the loss by this is aimed at.

Japanese Patent Laid-Open No. 11-74092

  However, in such a discharge lamp lighting device, since the start circuit 6 must be provided, there is a problem that the circuit of the device becomes complicated.

  An object of the present invention is to provide a power supply apparatus that does not require a starting circuit for a power supply voltage supply circuit.

According to the first aspect of the present invention, there is provided a rectifying and smoothing circuit for converting an AC voltage into a DC voltage, an active filter for boosting a DC voltage output from the rectifying and smoothing circuit to a predetermined DC voltage, and a boosting output from the active filter. An inverter that converts a DC voltage into a high-frequency voltage and applies it to a load; a control circuit that controls the inverter based on an external signal; and a power supply voltage supply circuit that supplies a power supply voltage to the control circuit. The supply circuit is a power supply device that operates by receiving a voltage for a power supply voltage from the active filter,
The control circuit is operated after operating the active filter when power is turned on.

  According to the present invention, since the start-up circuit is not necessary, the circuit can be simplified.

It is the circuit diagram which showed the structure of the power supply device which concerns on this invention. It is the circuit diagram which showed the structure of the conventional discharge lamp lighting device.

  Hereinafter, an embodiment which is an embodiment of a power supply device according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a discharge lamp lighting device 10 which is one of power supply devices. The discharge lamp lighting device 10 includes a rectifying and smoothing circuit 11 that converts an AC voltage into a DC voltage, an active filter 20 that boosts the DC voltage output from the rectifying and smoothing circuit 11 to a predetermined DC voltage, and the active filter 20. An inverter 30 that converts the stepped-up DC voltage output from the power source into a high-frequency voltage and applies it to the discharge lamp (load) 12, a dimming circuit 40 that detects an external dimming signal (external signal), and the dimming circuit Based on the dimming signal detected by 40, a control circuit 50 that controls the inverter 30 to turn on all light when there is no dimming signal, and a power supply voltage supply circuit 60 that supplies a power supply voltage to the control circuit 50 A low voltage detection circuit 70 for detecting that the DC voltage output from the rectifying / smoothing circuit 11 has fallen below a predetermined voltage, and the overvoltage and load current of the discharge lamp 12 And a failure detection circuit 80 for detecting a current imbalance) of the lamp 12.

  The active filter 20 includes a transformer 21, an active filter IC 22, a switch element 23, and the like. When the active filter IC 22 receives a DC voltage supplied from the rectifying / smoothing circuit 11 via the starting resistor Ra, the active filter IC 22 starts to operate and turns the switch element 23 on and off.

  One end of the secondary coil 21 a of the transformer 21 is connected to the anode of the diode 24 and the anode of the diode 26, and the cathode of the diode 24 is connected to one end of the resistor 25. The other end of the resistor 25 is connected to a power supply terminal (not shown) of the active filter IC 22, and a starting resistor Ra is connected to this power supply terminal.

  The power supply voltage supply circuit 60 includes a transistor 61, a Zener diode 62, a resistor 63, and the like. The transistor 61, the Zener diode 62, and the resistor 63 form a dropper circuit.

  A cathode of a Zener diode 62 is connected to the base of the transistor 61, and a resistor 63 is connected between the base and collector of the transistor 61. A capacitor 64 is connected between the anode of the Zener diode 62 and the collector of the transistor 61, and the collector of the transistor 61 is connected to the cathode of the diode 26 of the active filter 20. A capacitor 65 is connected between the emitter of the transistor 61 and the anode of the Zener diode 62.

  The emitter of the transistor 61 is connected to a power supply terminal (not shown) of the control IC of the control circuit 50 so that the power supply voltage is supplied from the transistor 61 to the control IC.

  The control circuit 50 has a control IC such as a CPU. When the low voltage detection circuit 70 detects a low voltage or the abnormality detection circuit 80 detects an overvoltage or imbalance of the discharge lamp 12, the oscillation of the inverter 30 is performed. Or the oscillation frequency of the inverter 30 or the boosted DC voltage of the active filter IC 22 is controlled based on the dimming signal detected by the dimming circuit 40.

Further, the control circuit 50 is set so as not to prohibit the active filter 20 from prohibiting the operation.
[Operation]
Next, the operation of the discharge lamp lighting device 10 configured as described above will be described.

  When the power is turned on, the DC voltage output from the rectifying / smoothing circuit 11 is supplied to the power supply terminal of the active filter IC 22 of the active filter 20 via the starting resistor Ra. The active filter IC 22 is activated when the DC voltage is supplied to the power supply terminal, and the switch element 23 is turned on / off because the control IC does not prohibit the operation.

  By this on / off operation of the switch element 23, a voltage is generated in the secondary coil 21a of the transformer 21, and the transistor 61 is turned on via the diode 26 by this voltage.

  When the transistor 61 is turned on, the voltage generated in the secondary coil 21a of the transformer 21 becomes a constant voltage (for example, 5V) by the dropper circuit including the transistor 61 and the Zener diode 62 and the like. Supplied to the power terminal.

  When the voltage generated in the secondary coil 21a of the transformer 21 rises and becomes higher than the Zener voltage (predetermined voltage) of the Zener diode 62, the transistor 61 is turned off, and the voltage to the power supply terminal of the control IC of the control circuit 50 Is stopped.

  By repeating these operations, a constant voltage is supplied from the power supply voltage supply circuit 60 to the power supply terminal of the control IC of the control circuit 50.

  As a result, the control IC starts up and controls the inverter 30 so that all lights are turned on, or controls the inverter 30 based on the dimming signal detected by the dimming circuit 40.

  In this way, after the active filter 20 is activated, the power supply voltage supply circuit 60 is activated and operated by the voltage generated in the secondary coil 21a of the transformer 21, so that the activation circuit is not required as in the prior art. Therefore, the circuit configuration of the discharge lamp lighting device 10 is simplified, the size can be reduced, and the inexpensive discharge lamp lighting device 10 can be provided.

  By the way, when the switch element 23 is turned on / off, the current flowing through the primary coil 21b of the transformer 21 is interrupted, and this intermittent operation generates a high voltage in the primary coil 21b, and this high voltage is passed through the diode D20 to the electrolytic capacitor C20. The high voltage of the electrolytic capacitor C20 is supplied to the inverter 30. Then, the inverter 30 converts the high voltage into a predetermined high-frequency voltage and applies it to the discharge lamp 12, whereby the discharge lamp 12 is lit.

  When the discharge lamp 12 shifts from all light to dimming, that is, when the dimming circuit 40 detects a dimming signal (dark light signal), the control circuit 50 changes the oscillation frequency of the inverter 30 to emit light from the discharge lamp 12. In addition to controlling the frequency to be darkened, the active filter IC 22 is controlled to lengthen the repetition cycle of the on / off operation of the switch element 23, thereby reducing the DC voltage (charge voltage of the electrolytic capacitor C 20) input to the inverter 30. To migrate.

  At this time, the repetition cycle of the on / off operation of the switch element 23 is gradually lengthened and gradually shifted to the low pressure side. By extending the transition time, the oscillation stop period of the inverter 30 is prevented from occurring.

  This is because if the ON / OFF operation repetition cycle of the switch element 23 is suddenly lengthened, the control capacitor IC 20 controls the active filter IC 22 to reduce the boosted current voltage, so that it is stored in the electrolytic capacitor C20. This is because the voltage cannot be lowered at a stroke, so that the overvoltage protection of the active filter IC 22 operates, and this operation causes an oscillation stop period.

  In the above embodiment, the case where the present invention is applied to the discharge lamp lighting device has been described. However, the present invention can also be applied to other power supply devices.

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

10 Discharge lamp lighting device (power supply device)
11 Rectification smoothing circuit 12 Discharge lamp (load)
20 Active Filter 30 Inverter 50 Control Circuit 60 Power Supply Voltage Supply Circuit

Claims (2)

A rectifying / smoothing circuit that converts AC voltage into DC voltage, an active filter that boosts the DC voltage output from the rectifying / smoothing circuit to a predetermined DC voltage, and a boosted DC voltage output from the active filter is converted into a high-frequency voltage And an inverter that is applied to the load, a control circuit that controls the inverter based on an external signal, and a power supply voltage supply circuit that supplies a power supply voltage to the control circuit, the power supply voltage supply circuit including the active filter A power supply device that operates by receiving a voltage for power supply voltage from
A power supply apparatus that operates the control circuit after operating the active filter when power is turned on. The load is a discharge lamp, the external signal is a dimming signal,
An abnormality detection circuit for detecting an abnormality of the discharge lamp;
A low voltage detection circuit that detects whether a voltage input to the active filter is a predetermined voltage or less,
2. The power supply device according to claim 1, wherein the control circuit stops oscillation of the inverter when the abnormality detection circuit detects an abnormality or when the low voltage detection circuit detects a low voltage.
The control circuit is characterized in that when the discharge lamp is shifted from all light to dimming by the dimming signal, the transition time when the boost voltage of the active filter is shifted from all light to dimming is lengthened. Power supply.

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