High efficiency driver circuitry for a solid state lighting fixture

• US 9,844,107 B2
• Filed: 08/25/2014
• Issued: 12/12/2017
• Est. Priority Date: 08/25/2014
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Hu, Yuequan, Medendorp, Jr., Nicholas William, Keiter, Douglas E.
• Primary Examiner(s): VU, JIMMY T
• Application Number:
  US14/467,251
• Publication Number:
  US 20160057825A1
• Time in Patent Office: 1,205 Days
• Field of Search: 315200 R, 315209 R, 315291, 315307, 315308, 315312, 315151, 315185 R
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/325 Pulse-width modulation [PWM]
• CPC Class Codes: H05B 45/355 Power factor correction [PFC]; Reactive power compensation
• CPC Class Codes: H05B 45/36 Circuits for reducing or suppressing harmonics, ripples or electromagnetic interferences [EMI]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/395 Linear regulators
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

Driver circuitry is coupled between a power supply and at least one LED in a solid-state lighting fixture, such that a non-isolated direct current (DC) path exists between the power supply and the at least one LED. The driver circuitry is configured to receive an AC input voltage and generate a driver output current for driving the at least one LED from the AC input voltage. By using driver circuitry that is non-isolated from the at least one LED in the solid-state lighting fixture, the efficiency of the driver circuitry may be increased, while simultaneously reducing the cost and complexity of the driver circuitry compared to conventional driver circuitry.

Claims

1. Driver circuitry configured to receive an alternating current (AC) input voltage and generate a driver current for driving at least one light emitting diode (LED) in a solid-state lighting fixture such that the driver circuitry operates at an efficiency greater than about 90% when the AC input voltage is between about 185V and 528V.

2. The driver circuitry of claim 1 wherein the driver circuitry operates at an efficiency greater than about 94% at one or more points when the AC input voltage is between 185V and 528V.

3. The driver circuitry of claim 1 wherein one or more switching components in the driver circuitry are silicon carbide (SiC) switching components.

4. The driver circuitry of claim 1 wherein a non-isolated direct current (DC) path exists between an input node of the driver circuitry and the at least one LED in the solid-state lighting fixture.

5. The driver circuitry of claim 1 wherein the driver circuitry comprises:

rectifier circuitry configured to receive and rectify the AC input voltage to generate a rectified voltage;

power factor correction (PFC) circuitry coupled to the rectifier circuitry and configured to receive and provide PFC to the rectified voltage to generate a PFC output voltage; and

DC-DC converter circuitry coupled to the PFC circuitry and configured to receive and regulate a driver output current for driving the at least one LED in the solid-state lighting fixture.

6. The driver circuitry of claim 5 wherein the PFC circuitry is a PFC boost converter.

7. The driver circuitry of claim 6 wherein the PFC boost converter is configured to operate in a continuous conduction mode (CCM).

8. The driver circuitry of claim 6 wherein the PFC boost converter comprises:

a boost converter input node and a boost converter output node;

a boost converter inductor coupled between the boost converter input node and an intermediate boost converter node;

a boost converter switch coupled between the intermediate boost converter node and ground;

a boost converter diode including an anode coupled to the intermediate boost converter node and a cathode coupled to the boost converter output node; and

a boost converter capacitor coupled between the boost converter output node and ground.

9. The driver circuitry of claim 8 wherein the boost converter switch and the boost converter diode are silicon carbide (SiC) devices.

10. The driver circuitry of claim 9 wherein the boost converter switch is a field effect transistor (FET) device.

11. The driver circuitry of claim 8 wherein the DC-DC converter circuitry is a buck converter.

12. The driver circuitry of claim 11 wherein the DC-DC converter circuitry comprises:

a buck converter input node coupled to the boost converter output node and a buck converter output node;

a buck converter diode including an anode coupled to the buck converter output node and an output coupled to the buck converter input node;

a buck converter switch coupled between the buck converter output node and ground; and

a buck converter inductor coupled in series with a buck converter capacitor between the buck converter input node and the buck converter output node.

13. The driver circuitry of claim 12 wherein the buck converter diode and the buck converter switch are silicon carbide (SiC) devices.

14. The driver circuitry of claim 13 wherein the buck converter switch is a field effect transistor (FET) device.

15. The driver circuitry of claim 12 wherein the buck converter switch is coupled to control circuitry configured to selectively change the state of the buck converter switch in order to control a current at the buck converter output node.

16. The driver circuitry of claim 15 wherein the control circuitry is coupled to minimum off-time circuitry configured to limit the minimum amount of time that the buck converter switch is turned off between switching cycles.

17. The driver circuitry of claim 12 wherein the boost converter diode, the boost converter switch, the buck converter diode, and the buck converter switch are silicon carbide (SiC) devices.

18. The driver circuitry of claim 17 wherein the boost converter switch and the buck converter switch are field effect transistor (FET) devices.

19. The driver circuitry of claim 1 wherein the driver circuitry has a power factor greater than about 0.9 for an input power equal to about 500 W.

20. The driver circuitry of claim 1 wherein the driver circuitry has a total harmonic distortion less than about 20% for an input power equal to about 500 W.

21. The driver circuitry of claim 1 wherein the driver circuitry drives the at least one LED with a linear driver current.

22. The driver circuitry of claim 1 wherein the driver circuitry drives the at least one LED with a pulse width modulated (PWM) driver current.

23. Circuitry comprising:

an input node coupled to a power supply;

an output node coupled to at least one LED in a solid-state lighting fixture such that a non-isolated direct current (DC) path exists between the input node and the output node; and

driver circuitry residing in the non-isolated DC path between the input node and the output node and configured to;

receive an AC input voltage from the power supply; and

generate a driver current for driving the at least one LED from the AC input voltage using one or more switching components in the driver circuitry such that the driver circuitry operates at an efficiency greater than about 90% when the AC input voltage is between about 185V and 528V.

24. The circuitry of claim 23 wherein the one or more switching components in the driver circuitry are silicon carbide (SiC) switching components.

25. The circuitry of claim 23 wherein the driver circuitry comprises:

rectifier circuitry configured to receive and rectify the AC input voltage to generate a rectified voltage;

power factor correction (PFC) circuitry coupled to the rectifier circuitry and configured to receive and provide PFC to the rectified voltage to generate a PFC output voltage; and

DC-DC converter circuitry coupled to the PFC circuitry and configured to receive and regulate a driver output current for driving the at least one LED in the solid-state lighting fixture.

26. The circuitry of claim 23 wherein the AC input voltage signal is between about 185V and 528V.

27. The circuitry of claim 23 wherein the driver circuitry has a power factor greater than about 0.9 for an input power equal to about 500 W.

28. The circuitry of claim 23 wherein the driver circuitry has a total harmonic distortion less than about 20% for an input power equal to about 500 W.