Dimming Circuit for Led Lighting Device With Means for Holding Triac in Conduction

• US 20080258647A1
• Filed: 05/19/2005
• Published: 10/23/2008
• Est. Priority Date: 05/19/2004
• Status: Active Grant

• Current Assignee: Dynamic LED Technologies, LLC (Equitable IP Corporation)
• Original Assignee: Goeken Group Corp.
• Inventors: Scianna, Carlo
• Granted Patent: US 7,872,427 B2
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: H05B 39/044 continuously H05B39/042 takes precedence
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/3575 by means of dummy loads or bleeder circuits, e.g. for dimmers
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/44 with an active control inside an LED matrix
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

The invention disclosed herein is a dynamic dummy load to allow a phase control dimmer to be used with LED lighting. The invention includes providing a dynamic dummy load to provide a load to the dimmer when the LED electronics do not provide sufficient load due to start up issues or ringing in the circuit, the dynamic dummy load providing a reduced flow of current when the LED and its converter electronics provide sufficient current draw from the dimmer. The system generally includes a power source electrically connected to a phase control dimmer, the phase control dimmer electrically connected to converter circuitry to convert the AC power output of the dimmer to DC power output for powering the LED lighting, a dynamic dummy load electrically connected in parallel with the converter circuitry, the dummy load varying its current draw in response to operation of the converter circuitry.

Claims

1. An electric circuit including a dimmer electrically connected in series between a power supply and an LED lighting converter, further including a dynamic dummy load placed in parallel with the LED lighting converter, the dynamic load receiving a control signal from the LED lighting converter, the dynamic dummy load adjusting the load in response to the signal.

2. The electric circuit of claim 1, further including a surge limiting element in series with the power source and the LED lighting converter.

3. The electric circuit of claim 2 wherein the surge limiting element is a constant current source.

4. The electric circuit of claim 1, wherein the control signal is a current signal.

5. The electric circuit of claim 1, wherein the LED lighting converter includes an AC to DC converter.

6. The electric circuit of claim 1, wherein the dimmer exhibits a bias current, the dynamic dummy load providing a load for the bias current prior to firing of the dimmer.

7. The electric circuit of claim 6, wherein the dynamic dummy load exhibits increased current flow upon firing of the dimmer.

8. A method of using a phase control dimmer with an LED to dim the LED, including the steps of:

providing a phase control dimmer connected to a power supply;

providing an LED electrically connected in series with the dimmer;

providing a dynamic dummy load in parallel with the LED,

varying the dynamic dummy load to draw current from the dimmer in excess of a hold current of the dimmer upon firing of the dimmer, and thereafter varying the load to draw less current as the current drawn by the LED exceeds the hold current.

9. The method of claim 8, further including the steps of providing a control signal to the dynamic dummy load.

10. A dimmable LED lighting system including:

a power source electrically connected to a phase control dimmer, the phase control dimmer electrically connected to converter circuitry to convert the AC power output of the dimmer to DC power output for powering the LED lighting,

a dynamic dummy load electrically connected in parallel with the converter circuitry, the dummy load varying its current draw in response to operation of the converter circuitry.

11. The system of claim 10, further including a control channel form the converter circuitry to the dynamic dummy load, the control channel carrying a control signal generated by the converter circuitry in response to the current provided to the LED.

12. The system of claim 10, further including a bridge rectifier electrically connected between the dimmer and the converter circuitry.

13. The system of claim 10 wherein the converter circuitry includes a transformer to reduce the voltage provided from the dimmer.

14. The system of claim 13, wherein the transformer also generates the control signal.

15. The system of claim 10, further including a surge limiting circuit electrically connected to the dynamic dummy load.