Solid-state lighting fixture with compound semiconductor driver circuitry

• US 10,271,390 B2
• Filed: 08/25/2014
• Issued: 04/23/2019
• 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): Hammond, Dedei K
• Application Number:
  US14/467,240
• Publication Number:
  US 20160057824A1
• Time in Patent Office: 1,702 Days
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology

Abstract

A lighting fixture includes a solid-state light source and driver circuitry. The solid-state light source includes at least one light emitting diode (LED). The driver circuitry includes one or more silicon carbide (SiC) switching components, and is coupled to the solid-state light source. Further, the driver circuitry is configured to receive an alternating current (AC) input voltage and generate a driver output current for driving the at least one LED from the AC input voltage. By using silicon carbide (SiC) for the switching components in the driver circuitry, the efficiency of the driver circuitry and thus the lighting fixture may be significantly increased, while simultaneously reducing the cost and complexity of the driver circuitry and thus the lighting fixture when compared to conventional lighting fixtures.

Claims

1. A lighting fixture comprising:

a solid state light source including at least one light emitting diode (LED) configured to provide a desired light output based on a driver current; and

driver circuitry configured to receive an alternating current (AC) input voltage and provide the driver current based on one or more control signals, the driver circuitry comprising;

one or more compound semiconductor switching devices;

a switching power converter comprising at least one of the one or more compound semiconductor switching devices and a power converter inductive element through which the driver current flows; and

control circuitry coupled to the driver circuitry and configured to provide the one or more control signals, the control circuitry comprising;

a control inductive element that is electromagnetically coupled to the power converter inductive element;

minimum off time circuitry coupled to the control inductive element and configured to provide a minimum off time signal based at least in part on a current through the control inductive element, wherein at least one of the one or more control signals delivered to the at least one of the one or more compound semiconductor switching devices in the switching power converter is based on the minimum off time signal such that the at least one of the one or more compound semiconductor switching devices in the switching power converter remains off for a minimum amount of time between switching periods.

2. The lighting fixture of claim 1 wherein the one or more compound semiconductor switching devices are silicon carbide (SiC) devices.

3. The lighting fixture of claim 1 wherein the one or more control signals are pulse width modulated (PWM).

4. The lighting fixture of claim 1 wherein at least one of the one or more compound semiconductor switching devices is a diode.

5. The lighting fixture of claim 1 wherein at least one of the one or more compound semiconductor switching devices is a transistor.

6. The lighting fixture of claim 5 wherein at least one of the one or more compound semiconductor switching devices is a field-effect transistor (FET) device.

7. The lighting fixture of claim 6 wherein at least one of the one or more compound semiconductor switching devices is a metal-oxide-semiconductor field-effect transistor (MOSFET) device.

8. The lighting fixture of claim 1 wherein the driver circuitry further comprises:

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

9. The lighting fixture of claim 8 wherein the driver circuitry further comprises a first power converter stage, which is a power factor correction (PFC) boost power converter stage configured to receive and provide power factor correction to the rectified voltage to generate a PFC output voltage, and a second power converter stage, which is the switching power converter.

10. The lighting fixture of claim 9 wherein the rectifier circuitry is a bridge rectifier.

11. The lighting fixture of claim 9 wherein the first power converter stage is configured to operate in a continuous conduction mode and the switching power converter is configured to operate in a critical conduction mode.

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

13. The lighting fixture 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.

14. The lighting fixture of claim 1 wherein the driver current is pulse-width modulated (PWM).

15. The lighting fixture of claim 1 wherein the one or more control signals operate the one or more compound semiconductor switching devices at a frequency greater than about 200 kHz.

16. A lighting fixture comprising:

a solid state light source including at least one light emitting diode (LED) configured to provide a desired light output based on a driver current;

driver circuitry configured to receive an alternating current (AC) input voltage and provide the driver current based on one or more control signals, the driver circuitry comprising one or more compound semiconductor switching devices; and

control circuitry coupled to the driver circuitry and configured to provide the one or more control signals based at least in part on a dimming input signal, the control circuitry comprising;

a dimming input signal receiver portion configured to receive the dimming input signal;

a control signal generator portion configured to generate the one or more control signals based at least in part on the dimming input signal; and

an optocoupler between the dimming input signal receiver portion and the control signal generator portion, the dimming input signal receiver portion and the control signal generator portion being electrically isolated from one another.

17. The lighting fixture of claim 16 wherein the one or more compound semiconductor switching devices are silicon carbide (SiC) devices.

18. The lighting fixture of claim 16 wherein the one or more control signals are pulse width modulated (PWM).

19. The lighting fixture of claim 16 wherein at least one of the one or more compound semiconductor devices is a diode.

20. The lighting fixture of claim 16 wherein at least one of the one or more compound semiconductor switching devices is a transistor.

21. The lighting fixture of claim 16 wherein the driver circuitry further comprises rectifier circuitry configured to receive and rectify the AC input voltage to generate a rectified voltage.

22. The lighting fixture of claim 21 wherein the driver circuitry further comprises a first power converter stage, which is a power factor correction (PFC) boost power converter stage configured to receive and provide power factor correction to the rectified voltage to generate a PFC output voltage.

23. The lighting fixture of claim 22 wherein the driver circuitry further comprises a second power converter stage, which is a buck power converter stage.

24. The lighting fixture of claim 23 wherein the first power converter stage is configured to operate in a continuous conduction mode and the second power converter stage is configured to operate in a critical conduction mode.

25. The lighting fixture of claim 16 wherein the driver circuitry has an efficiency above 90% when the AC input voltage is between about 185V and 528V, and an efficiency above 94% at one or more points in the AC input voltage between about 185V and 528V.

26. The lighting fixture of claim 16 wherein the driver circuitry has a power factor greater than 0.9 for an input power equal to about 500 W.

27. The lighting fixture of claim 16 wherein the driver circuitry has a total harmonic distortion less than about 20% for an input power equal to about 500 W.

28. The lighting fixture of claim 16 wherein the driver circuitry is non-isolated.

29. The lighting fixture of claim 16 wherein the one or more control signals operate the one or more compound semiconductor devices at a frequency greater than about 200 kHz.

30. A lighting fixture comprising:

a solid state light source including at least one light emitting diode configured to provide a desired light output based on a driver current;

driver circuitry configured to receive an alternating current input voltage and provide the driver current based on one or more control signals, the driver circuitry comprising one or more compound semiconductor switching devices;

control circuitry coupled to the driver circuitry and configured to provide at least one of the one or more control signals based at least in part on a dimming input signal;

dimming control circuitry configured to provide the dimming input signal; and

an occupancy control module coupled to the dimming control circuitry and configured to provide at least one of the one or more control signals to the dimming control circuitry.

31. The lighting fixture of claim 30 wherein the one or more compound semiconductor switching devices are silicon carbide devices.

32. The lighting fixture of claim 30 wherein the occupancy control module comprises an occupancy control switch and an occupancy control sensor.

33. The lighting fixture of claim 32 wherein the occupancy control sensor is configured to open the occupancy control switch and cut power to the driver circuitry.

34. The lighting fixture of claim 32 wherein the occupancy control sensor is configured to dim the at least one light emitting diode.

35. The lighting fixture of claim 30 further comprising a housing wherein the driver circuitry is provided on a first side of the housing and the occupancy sensor is provided on a second side of the housing that is opposite the first.

36. A lighting fixture comprising:

a solid state light source including at least one light emitting diode (LED) configured to provide a desired light output based on a driver current; and

driver circuitry configured to receive an alternating current (AC) input voltage and provide the driver current based on one or more control signals, the driver circuitry comprising;

one or more compound semiconductor switching devices;

a switching power converter comprising at least one of the one or more compound semiconductor switching devices and a power converter inductive element through which the driver current flows, wherein the switching power converter is a buck power converter stage; and

control circuitry coupled to the driver circuitry and configured to provide the one or more control signals, the control circuitry comprising a control inductive element that is electromagnetically coupled to the power converter inductive element, and the one or more control signals being based at least in part on a signal induced in the control inductive element by the power converter inductive element.

37. A lighting fixture comprising:

a solid state light source including at least one light emitting diode (LED) configured to provide a desired light output based on a driver current; and

driver circuitry configured to receive an alternating current (AC) input voltage and provide the driver current based on one or more control signals, the driver circuitry comprising;

one or more compound semiconductor switching devices;

a switching power converter comprising at least one of the one or more compound semiconductor switching devices and a power converter inductive element through which the driver current flows, wherein the driver circuitry has an efficiency above 90% for an AC input voltage between about 185V and 528V, and an efficiency above 95% at one or more points in the AC input voltage between about 185V and 528V; and

control circuitry coupled to the driver circuitry and configured to provide the one or more control signals, the control circuitry comprising a control inductive element that is electromagnetically coupled to the power converter inductive element, and the one or more control signals being based at least in part on a signal induced in the control inductive element by the power converter inductive element.

38. A lighting fixture comprising:

a solid state light source including at least one light emitting diode (LED) configured to provide a desired light output based on a driver current; and

driver circuitry configured to receive an alternating current (AC) input voltage and provide the driver current based on one or more control signals, the driver circuitry comprising;

one or more compound semiconductor switching devices;

a switching power converter comprising at least one of the one or more compound semiconductor switching devices and a power converter inductive element through which the driver current flows; and

control circuitry coupled to the driver circuitry and configured to provide the one or more control signals such that the driver current is linearly changed, the control circuitry comprising a control inductive element that is electromagnetically coupled to the power converter inductive element, and the one or more control signals being based at least in part on a signal induced in the control inductive element by the power converter inductive element.

39. A lighting fixture comprising:

a solid state light source including at least one light emitting diode (LED) configured to provide a desired light output based on a driver current; and

driver circuitry configured to receive an alternating current (AC) input voltage and provide the driver current based on one or more control signals, the driver circuitry being non-isolated and comprising;

one or more compound semiconductor switching devices;

a switching power converter comprising at least one of the one or more compound semiconductor switching devices and a power converter inductive element through which the driver current flows; and

control circuitry coupled to the driver circuitry and configured to provide the one or more control signals, the control circuitry comprising a control inductive element that is electromagnetically coupled to the power converter inductive element, and the one or more control signals being based at least in part on a signal induced in the control inductive element by the power converter inductive element.