Power factor correction and driver circuits

• US 7,952,293 B2
• Filed: 04/30/2008
• Issued: 05/31/2011
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: LSI Industries Incorporated
• Original Assignee: LSI Industries Incorporated
• Inventors: Kelly, Kevin Allan
• Primary Examiner(s): TRAN, THUY V
• Application Number:
  US12/112,101
• Publication Number:
  US 20090273297A1
• Time in Patent Office: 1,126 Days
• Field of Search: 315/209.R, 315/246, 315/247, 315/276, 315/283, 315/291, 315/307
• US Class Current: 315/209.00R
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H05B 45/355 Power factor correction [PFC]; Reactive power compensation
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Power factor correction and driver circuits and stages are described. More particularly, power factor correction circuits are described that utilize an auxiliary inductor winding for power regulation. Driver circuits configured for electrical loads such as series arrangements of light emitting diodes are also described. An exemplary embodiment of a driver circuit can implement a comparator and/or a voltage regulator to allow for improved output current uniformity for high-voltage applications and loads, such as series configurations of LEDs. Embodiments of PFC stages and driver stages can be combined for use as a power supply, and may be configured on a common circuit board. Power factor correction and driver circuits can be combined with one or more lighting elements as a lighting apparatus.

Claims

1. A lighting apparatus driver circuit comprising:

a driver control circuit including a driver controller;

a comparator circuit including a comparator, wherein the comparator is connected to the driver control circuit;

a voltage regulator including a transistor connected to the comparator circuit; and

a diode configured to provide a return path for a current through an electrical load and inductor during the transistor switch off time;

wherein the driver circuit regulates the current supplied to the electrical load at a nominal current plus or minus about 2%.

2. The driver circuit of claim 1, wherein the voltage regulator comprises a shunt regulator.

3. The driver circuit of claim 1, wherein the comparator comprises a single differential comparator.

4. The driver circuit of claim 1, wherein the diode comprises a silicon carbide Schottky diode.

5. The driver circuit of claim 1, further comprising an input configured and arranged to received power with a voltage of about 400 V.

6. The driver circuit of claim 5, further comprising a capacitor bank configured between the input and ground.

7. The driver circuit of claim 1, wherein the comparator is connected to a current sensing input of the driver controller.

8. The driver circuit of claim 7, wherein the driver controller is a HV9910 controller.

9. A lighting power supply comprising:

(i) a PFC stage including;

an EMI filter configured to receive a AC input from an AC power supply;

a rectifier connecting the EMI filter portion, the rectifier being configured to receive AC power from the EMI filter and produce a rectified current;

a boost circuit connected to the rectifier and including a PFC controller and a PFC coil with an auxiliary winding, the boost circuit being configured to receive the rectified current and to produce a power factor corrected output with a higher voltage than the AC input of the AC power supply; and

a voltage regulator connected to the auxiliary winding and including a common emitter amplifier portion including a common emitter amplifier transistor connected to the auxiliary winding, wherein the voltage regulator is configured to regulate a voltage supplied by the auxiliary winding to a desired voltage for application to the power factor correction controller; and

(ii) a driver stage, configured and arranged to receive output from the PFC stage and supply as an output power to an electrical load, the driver stage including a driver controller, wherein the driver stage comprises

a driver control circuit including a driver controller,

a comparator circuit including a comparator, wherein the comparator is connected to the driver control circuit, a voltage regulator connected to the comparator circuit, and

a diode configured to provide a return path for a current through an electrical load and inductor during the transistor switch off time;

wherein the driver control circuit regulates the current supplied to the electrical load at a nominal current plus or minus about 2%.

10. The power supply of claim 9, wherein the voltage regulator comprises a shunt regulator.

11. The power supply of claim 9, wherein the comparator comprises a single differential comparator.

12. The power supply of claim 9, wherein the diode comprises a silicon carbide Schottky diode.

13. The power supply of claim 9, further comprising an input configured and arranged to received power with a voltage of about 400 V.

14. The power supply of claim 13, further comprising a capacitor bank configured between the input and ground.

15. The power supply of claim 9, wherein the comparator is connected to a current sensing input of the driver controller.

16. The power supply of claim 15, wherein the driver controller is a HV9910 controller.

17. The power supply of claim 9, wherein the PFC stage and the driver stage are configured and arranged on a common circuit board.

18. The power supply of claim 9, wherein the boost portion comprises a charge pump.

19. The power supply of claim 9, wherein the boost portion is configured and arranged in a critical conduction mode topology.

20. The power supply of claim 9, wherein the voltage regulator further comprises a Zener diode connected to a base and an emitter of the common emitter amplifier transistor.

21. The power supply of claim 9, wherein the voltage regulator further comprises a diode coupled in series between the auxiliary winding and the common emitter amplifier transistor.

22. The supply of claim 21, wherein the voltage regulator further comprises a storage capacitor coupled between the diode and ground.

23. The power supply of claim 9, wherein the EMI filter is configured and arranged to receive a 120 V AC input and the boost circuit is configured and arranged to produce an output of about 400 V DC.

24. The power supply of claim 9, wherein the PFC controller is a NCP1606 controller.