DIMMABLE LED LAMP

• US 20120286696A1
• Filed: 03/30/2012
• Published: 11/15/2012
• Est. Priority Date: 05/13/2011
• Status: Active Grant

• Current Assignee: Savant Technologies, LLC (Savant Systems, LLC)
• Original Assignee: General Electric Company
• Inventors: Ghanem, Mohamed Cherif
• Granted Patent: US 8,933,642 B2
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/59 for reducing or suppressing flicker or glow effects
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A driver for an LED lamp assembly includes a rectifier configured to receive an AC power and produce a first DC power and a switching regulator coupled to the rectifier. The switching regulator is configured to receive the first DC power and produce an output DC power. The driver also includes a current controller coupled between the rectifier and the switching regulator. The current controller is configured to damp and stabilize an electric current flowing between the switching regulator and the rectifier.

Claims

1. A driver for an LED lamp assembly comprising:

a rectifier configured to receive an AC power and produce a first DC power;

a switching regulator coupled to the rectifier, the switching regulator configured to receive the first DC power and produce an output DC power; and

a current controller coupled between the rectifier and the switching regulator, the current controller configured to damp and stabilize an electric current flowing between the switching regulator and the rectifier.

2. The driver of claim 1, wherein the switching regulator comprises:

an output transformer, the output transformer having a primary side and a secondary side, wherein the primary side is coupled to the first DC power, and the secondary side is coupled to the output DC power such that the first DC power is electrically isolated from the output DC power;

a power factor controller configured to maintain an electric current drawn from the first DC power substantially in phase with a voltage of the first DC power; and

a power regulator, the power regulator configured to maintain the output DC power at a generally constant level based at least in part on a current flowing through the primary side.

3. The driver of claim 2, wherein the power regulator is further configured to vary the output DC power proportionately to the voltage of the first DC power when the voltage of the first DC power is below a predetermined level.

4. The driver of claim 1, comprising a filter circuit coupled between the current controller and the switching regulator, the filter circuit configured to remove noise and high frequency components from the first DC power.

5. The driver of claim 1, comprising a surge protector coupled between the rectifier and the AC power, the surge protector configured to limit a voltage of the AC power to a predetermined maximum value.

6. The driver of claim 2, comprising a dimmer coupled between the AC power and the rectifier, the dimmer configured to receive a first AC power and provide a second AC power to the rectifier such that an average voltage of the second AC power is less than or equal to an average voltage of the first AC power.

7. The driver of claim 2, comprising a starting circuit coupled to the switching regulator wherein the starting circuit is configured as a conflict monitor.

8. The driver of claim 1, wherein the switching regulator further comprises an over voltage protection circuit configured to prevent a voltage of the output DC power from exceeding a predetermined maximum value.

9. A dimmable LED light source, the light source comprising:

a rectifier configured to receive an AC power and produce a first DC power;

a switching regulator coupled to the rectifier, the switching regulator configured to receive the first DC power and produce an output DC power; and

an LED lamp coupled to the output DC power,

wherein the switching regulator comprises;

an output transformer, the output transformer comprising a primary side and a secondary side, wherein the primary side is coupled to the first DC power, and the secondary side is coupled to the output DC power such that the first DC power is electrically isolated from the output DC power;

a power factor controller configured to maintain an electric current drawn from the first DC power substantially in phase with a voltage of the first DC power; and

a power regulator, the power regulator configured to maintain the output DC power at a generally constant value based at least in part on a current flowing in the primary side.

10. The dimmable LED light source of claim 9, comprising a current controller coupled between the rectifier and the switching converter and configured to present a variable impedance to a rectifier current flowing from the switching converter to the rectifier when an amount of the rectifier current exceeds a predetermined value, and to present a generally constant impedance to the rectifier current when the amount of the rectifier current does not exceed the predetermined value, the constant impedance is less than the variable impedance.

11. The dimmable LED light source of claim 10 comprising a filter circuit coupled between the current controller and the switching converter, the filter circuit configured to limit the rate of change of the voltage of the first DC power.

12. The dimmable LED light source of claim 10, comprising a dimmer coupled between the AC power and the rectifier, the dimmer configured to receive a first AC power and provide a second AC power to the rectifier such that an average voltage of the second AC power is less than or equal to an average voltage of the first AC power.

13. The dimmable LED light source of claim 9, wherein the power regulator is further configured to regulate the output power at a generally constant value when an average of the voltage of the first DC power exceeds a predetermined value.

14. The dimmable LED light source of claim 9, comprising a surge protector coupled between the AC power and the rectifier, the surge protector configured to limit a voltage of the AC power to a predetermined maximum value.

15. The dimmable LED light source of claim 9, comprising a starting circuit coupled to the switching regulator wherein the starting circuit is configured as a conflict monitor.

16. The dimmable LED light source of claim 9, wherein the switching regulator further comprises an over voltage protection circuit configured to prevent a voltage of the output DC power from exceeding a predetermined maximum value.

17. The dimmable LED light source of claim 9, wherein the LED lamp comprises one or more light emitting diodes.

18. A method for driving a dimmable LED lamp assembly, wherein the LED lamp assembly includes at least one LED lamp, a switching power supply, a current control circuit, and a rectifier, the method comprising:

receiving an AC power into the rectifier;

converting the AC power to a DC power with the rectifier and switching power supply;

providing the DC power to the LED lamp; and

determining if the AC power is supplied by a dimmer; and

if a dimmer is supplying the AC power;

damp and stabilize a current drawn from the AC power with the current control circuit; and

vary the DC power as a function of a voltage of the AC power, and

if a dimmer is not supplying the AC power;

regulate a power factor of the lamp assembly between about 0.99 and 1.0;

maintain a total harmonic distortion of the AC power less than about 20%;

regulate a LED lamp current at a predetermined value.

19. The method according to claim 18, wherein converting the AC power to a DC power further comprises:

enabling a starting circuit with the AC power;

starting the switching power supply with the starting circuit; and

disabling the starting circuit once the power supply is started.