Apparatus and method of operation of a low-current LED lighting circuit

• US 20140117866A1
• Filed: 01/08/2013
• Published: 05/01/2014
• Est. Priority Date: 10/26/2012
• Status: Active Grant

• Current Assignee: Liteideas, LLC
• Original Assignee: Liteideas, LLC
• Inventors: Hodrinsky, Todd W., Wesson, Donald T. Jr.
• Granted Patent: US 8,890,427 B2
• Time in Patent Office: Days
• US Class Current: 315/201
• CPC Class Codes: H02M 1/14 Arrangements for reducing ripples from dc input or output
• CPC Class Codes: H02M 7/062 Avoiding or suppressing excessive transient voltages or currents
• CPC Class Codes: H05B 45/37 Converter circuits
• 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

An apparatus and method of operation of a low-current LED lighting circuit are disclosed. The invention utilizes high AC voltage input and unreduced voltage ripple component of the rectified DC power signal, which provides the ability to drive an LED load at high power factor at low current. The invention discloses both active and passive circuits to limit the peak current flowing to the LED and create a current source for the LED load. The proposed circuit increases reliability by optionally eliminating capacitor, inductor, and heatsink components while minimizing luminous flux fluctuations.

Claims

1. An LED lighting circuit comprising:

a rectification circuit for converting an AC input power signal to a rectified DC power signal;

a peak current limiting circuit electrically coupled to the rectification circuit for providing a peak current limiting means from the voltage ripple of said rectified DC power signal, wherein said voltage ripple is intentionally unreduced, whose output creates a current source; and

an LED mesh circuit electrically coupled to the output of the peak current limiting circuit and receives said current source as an input.

2. The LED lighting circuit of claim 1, wherein one or more resistors provide said peak current limiting means.

3. The LED lighting circuit of claim 1, wherein an active circuit provides said peak current limiting means.

4. The LED lighting circuit of claim 1, wherein capacitor, inductor, and heatsink components are omitted.

5. The LED lighting circuit of claim 1, wherein said LED mesh circuit comprises at least one LED.

6. The LED lighting circuit of claim 1, wherein said LED lighting circuit is encapsulated by an electrically insulating material.

7. The LED lighting circuit of claim 1, wherein the AC input power range is between 50 VRMS, inclusive, and 350 VRMS, inclusive, with a maximum of 20% of the AC input power allocated to the peak current limiting circuit, with said current source equal to or less than 20 mA per LED.

8. The LED lighting circuit of claim 1, wherein said unreduced voltage ripple input to said peak current limiting circuit is allowed to vary, and at least one electrical characteristic of at least one of the LEDs in said LED mesh circuit is chosen such that variations in the luminous flux intensity are rendered unobservable to the human eye.

9. The LED lighting circuit of claim 1, further comprising a potentiometer AC dimmer circuit connected to the AC power input signal that limits the voltage across the peak current limiting circuit, thereby making the LED mesh circuit dimmable.

10. The LED lighting circuit of claim 1, further comprising a triac AC dimmer circuit connected to the AC power input signal that lowers the duty cycle of the peak current limiting circuit, thereby making the LED mesh circuit dimmable.

11. A method of operating an LED lighting circuit, comprising the steps of:

rectifying an AC power input signal to a rectified DC power signal;

producing an intentionally unreduced voltage ripple from said rectified DC power signal;

electrically coupling a peak current limiting circuit to the rectification circuit for providing a peak current limiting means from the voltage ripple of said rectified DC power signal, wherein said voltage ripple is intentionally unreduced, whose output creates a current source; and

electrically coupling an LED mesh circuit to the output of the peak current limiting circuit and receiving said current source as an input.

12. The method of claim 11, wherein the peak current limiting means is accomplished using one or more resistors.

13. The method of claim 11, wherein the peak current limiting means is accomplished by using an active circuit.

14. The method of claim 11, wherein capacitor and inductor and heatsink components are omitted.

15. The method of claim 11, wherein said LED mesh circuit comprises at least one LED.

16. The method of claim 11, wherein said LED lighting circuit is encapsulated by an electrically insulating material.

17. The method of claim 11, wherein the AC input power range is between 50 VRMS, inclusive, and 350 VRMS, inclusive, with a maximum of 20% of the AC input power allocated to the peak current limiting circuit, with said current source equal to or less than 20 mA per LED.

18. The method of claim 11, wherein said unreduced voltage ripple input to said peak current limiting circuit is allowed to vary, and at least one electrical characteristic of at least one of the LEDs in said LED mesh circuit is chosen such that variations in the luminous flux intensity are rendered unobservable to the human eye.

19. The method of claim 11, further comprising connecting a potentiometer AC dimmer circuit to the AC input power signal that limits the voltage across the peak current limiting circuit, thereby making the LED mesh circuit dimmable.

20. The method of claim 11, further comprising connecting a triac AC dimmer circuit to the AC power input signal that limits the voltage across the peak current limiting circuit, thereby making the LED mesh circuit dimmable.