LED DRIVER WHICH CAN BE USED WITH EITHER TRAILING EDGE OR LEADING EDGE DIMMERS

• US 20160381745A1
• Filed: 09/02/2015
• Published: 12/29/2016
• Est. Priority Date: 06/26/2015
• Status: Active Grant

• Current Assignee: Eptronics, Inc.
• Original Assignee: Eptronics, Inc.
• Inventors: O'Neil, Tom, Chiang, Lee
• Granted Patent: US 9,699,849 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/36 Circuits for reducing or suppressing harmonics, ripples or electromagnetic interferences [EMI]
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/385 using flyback topology
• CPC Class Codes: H05B 47/10 Controlling the light source
• CPC Class Codes: H05B 47/20 Responsive to malfunctions or to light source life; for protection
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A phase control dimming LED driver is able to achieve complete stabilization of both TRIAC and trailing edge dimmers by using a large inductor to limit the inrush normally associated with the switching on of the TRIAC during each half cycle. Such a large inductor is not normally used because when a trailing edge dimmer is applied, a damaging voltage surge known as “ring up” can be generated when the trailing edge dimmer switch turns off. In this invention the inductor is placed after the input rectifier bridge and equipped with a diode and resistor which allow the energy in the inductor at the moment when a trailing edge dimmer switches off to be harmlessly dissipated.

Claims

1. ) A dimmable primary side regulated lighting drive circuit suitable for operation by any of trailing edge dimming, leading edge dimming or universal dimming, comprising the following functions connected in succession starting from the input comprising:

a. input terminals for connecting to a phase controlled dimming power line circuit and output terminals for connecting to a lamp, wherein the input terminals are connected to a common mode emi filter, which is connected to a bridge rectifier unit with input and output terminals, which are connected to

b. a phase control wave filter including an inductor, a resistor and a single diode, wherein the phase control wave filter is directly adjacent to a DC side of a bridge rectifier and containing the single diode connected to an output terminal of the bridge rectifier, wherein the single diode is oriented such that current cannot pass between the bridge rectifier and the single diode, wherein the phase control wave filter is connected to a pi filter, wherein the wave filter has the single diode connected to the output terminal of the bridge rectifier.

2. ) The dimmable lighting drive circuit of claim 1, wherein the lamp comprises at least one light emitting diode.

3. ) The dimmable lighting drive circuit of claim 2, wherein the resistor is present in series with the single diode and wherein the single diode and the resistor are connected to the inductor to comprise a parallel path so that freewheeling current passes from the inductor and through both the single diode and the resistor.

4. ) The dimmable lighting drive circuit of claim 3, wherein the phase control dimming is chosen from the group of leading edge dimming, trailing edge dimming, or universal dimming.

5. ) A method for providing a stable interface between a dimmable primary side regulated lighting drive circuit and phase control dimmers, comprising the steps of:

a. incorporating a phase control wave filter having an inductor with the series combination of a resistor and a single diode in parallel with it; and

b. directly connecting the wave filter to the output of a power line connected bridge rectifier in such a manner that a current flow through the inductor is unidirectional, and connecting the output of the wave filter to a pi filter.

6. ) The method of claim 5, wherein when current coming out of the power line connected bridge rectifier is interrupted by voltage fluctuations of a phase control process, the current flow through the inductor freewheels through the resistor and diode.

7. ) (canceled)

8. ) (canceled)