INPUT CURRENT REGULATOR, DRIVING METHOD THEREOF, AND DISABLE CIRCUIT THEREOF

• US 20120299572A1
• Filed: 05/22/2012
• Published: 11/29/2012
• Est. Priority Date: 05/23/2011
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Korea Semiconductor Limited (ON Semiconductor Corporation)
• Inventors: EOM, Hyun-Chul, YANG, Seunguk
• Granted Patent: US 9,468,048 B2
• Time in Patent Office: Days
• US Class Current: 323/312
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/385 using flyback topology
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

The present invention relates to a dimmer and an input current regulator provided in a power supply. The input current regulator includes: a bleeding circuit generating a bleeding current from an input current passed through the dimmer; a sensing circuit sensing the input current, and controlling the bleeding circuit according to a sense voltage corresponding to the input current; and a biasing circuit generating a power voltage for operation of the input current regulator during operation of the power supply. The input current includes a bleeding current and a power current supplied to the power supply.

Claims

1. A dimmer and an input current regulator provided in a power supply, comprising:

a bleeding circuit generating a bleeding current from an input current passed through the dimmer;

a sensing circuit sensing the input current, and controlling the bleeding circuit according to a sense voltage corresponding to the input current when the sensed input current is smaller than a predetermined holding current; and

a biasing circuit generating a power voltage for operation of the input current regulator during operation of the power supply.

2. The input current regulator of claim 1, wherein the biasing circuit generates the power voltage using an auxiliary voltage generated in an auxiliary coil coupled in an insulated manner with a primary side coil of the power supply with a predetermined turn ratio.

3. The input current regulator of claim 1, wherein the sensing circuit generates a sink current controlling a source current supplied to the bleeding circuit from the biasing circuit.

4. The input current regulator of claim 3, wherein the sensing circuit comprises a shunt regulator provided between a reference end and an input end to receive the sensing voltage and generating a sink current to the input end from an output end to maintain the sensing voltage with a predetermined reference voltage.

5. The input current regulator of claim 4, wherein the sensing circuit further comprises a first resistor connected between the input end and the reference end of the shunt regulator.

6. The input current regulator of claim 5, wherein the sensing circuit further comprises a capacitor coupled to the first resistor in parallel to filter the sensing voltage generated in the first resistor.

7. The input current regulator of claim 4, wherein the bleeding circuit comprises:

a first resistor having a first end connected to a rectification circuit and the power supply; and

a transistor having a first electrode connected to a second end of the first resistor and a control electrode connected to the output end of the shunt regulator.

8. The input current regulator of claim 7, wherein the bleed circuit comprises a second resistor connected between a second electrode of the transistor and the reference end of the shunt regulator.

9. The input current regulator of claim 3, wherein the sensing circuit comprises a BJT receiving a sense voltage according to the input current as a voltage difference between a control electrode and a first electrode, and

a sink current according to the voltage different flows to the first electrode of the BJT from the second electrode of the BJT.

10. The input current regulator of claim 9, wherein the bleeding circuit comprises a first resistor having a first end connected to a rectification circuit and the power supply and a transistor having a first electrode connected to a second end of the first resistor and a control electrode connected to a second electrode of the BJT.

11. The input current regulator of claim 10, wherein the bleeding circuit comprises a second resistor connected between a second electrode of the transistor and a control electrode of the BJT.

12. The input current regulator of claim 2, wherein the biasing circuit comprises a diode connected to the auxiliary voltage and a capacitor charged by a current flowing through the diode, and the power voltage is a voltage charged in the capacitor.

13. The input current regulator of claim 12, wherein the sensing circuit comprises a shunt regulator having a reference end, an input end, and an output end, receiving a sense voltage according to the input current between the reference end and the input end, and generating a sink current flowing to the input end from the output end according to the sense voltage, and

a capacitor of the biasing circuit has a first end connected to the output end of the shunt regulator through a resistor and a second end connected to an input end of the shunt regulator.

14. The input current regulator of claim 13, wherein the bleeding circuit comprises a transistor having a control electrode connected to the output end of the shunt regulator, a first electrode connected to the dimmer through a third resistor, and a second electrode connected to the reference end of the shunt regulator through a fourth resistor.

15. The input current regulator of claim 12, wherein the sensing circuit comprises a BJT receiving a sense voltage according to the input current as a voltage difference between a control electrode and a first electrode, a sink current according to the voltage difference flows to a first electrode of the BJT from a second electrode of the BJT, and a capacitor of the biasing circuit includes a first end connected with the second electrode of the BJT through a fifth resistor and a second end connected to the first electrode of the BJT.

16. The input current regulator of claim 15, wherein the bleeding circuit comprises a control electrode connected to the second electrode of the BJT, a first electrode connected to the dimmer through a third resistor, and a second electrode connected to a control electrode of the BJT through a fourth resistor.

17. The input current regulator of claim 1, wherein the sensing circuit senses an input current using the sum of the bleeding current and a current supplied from the power supply, and the current supplied to the sensing circuit from the power supply is a current flowing to a switch that controls power transmission of the power supply.

18. A disable circuit connected to the input current regulator of claim 1, comprising:

a dimming angle sensing circuit generating a comparison voltage according to a comparison result of an input voltage generated from rectification of an AC input that has passed through the dimmer and generating a dimming angle sense voltage corresponding to a dimming angle of the dimmer by low-pass filtering the comparison voltage; and

a dimming angle shunt regulator connected when a voltage between a reference end receiving the diming angle sense voltage and an input end is higher than a predetermined dimming angle reference voltage to generate a sink current flowing to the input end from an output end to which the power voltage is supplied.

19. The disable circuit of claim 18, wherein the comparing circuit comprises a zener diode receiving the input voltage from a sixth resistor and connected when the input voltage is higher than the zener voltage, and the comparison voltage is a voltage of a first node where the sixth resistor and the zener diode are connected.

20. The disable circuit of claim 18, wherein the filtering circuit comprises seventh and eighth resistors connected between the comparison voltage and a ground and a capacitor connected between a node where the seventh and eighth resistors are connected and the ground, and the dimming angle sense voltage is a voltage of the second node.

21. The disable circuit of claim 20, wherein the ground of the disable circuit is connected to the ground of the input current regulator.

22. The disable circuit of claim 20, wherein the ground of the disable circuit is connected to the ground of the power supply.

23. A driving method of a dimmer and an input current regulator provided in a power supply, comprising:

generating a sink current according to a sense voltage that depends on an input current passed through the dimmer;

generating a power voltage for operation of the input current regulator during operation of the power supply connected to the dimmer; and

controlling a bleeding current among the input current, excluding a current supplied to the power supply, according to the sink current.

24. The driving method of claim 23, wherein the controlling of the bleeding current comprises variation of a voltage supplied to a control electrode of the transistor by the power voltage according to the sink current, and the bleeding current flows through the transistor.

25. The driving method of claim 24, wherein the generating the sink current comprises generating a sense voltage from flow of the sum of a current flowing to a switch that controls power transmission of the power supply and the bleeding current to a resistor.

26. The driving method of claim 23, comprising:

generating a comparison voltage according to a comparison result of an input voltage generated by rectifying a dimmer-passed AC input and a zener voltage;

generating a dimming angle sense voltage corresponding to a dimming angle of the dimmer by low-pass filtering the comparison voltage; and

decreasing of the power voltage by a sink current when the dimming angle sense voltage is higher than a predetermined dimming angle reference voltage.