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Dimming of LED driver

A technology of LED driver and optical driver, applied in the direction of light source, electric light source, electroluminescence light source, etc., can solve the problems of hard switching converter not having high efficiency and unstable duty cycle, etc.

Active Publication Date: 2012-07-04
SIGNIFY HLDG BV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of using hard-switching converters are that hard-switching converters do not have high efficiency and they generate relatively high levels of electromagnetic interference (EMI)
Duty cycle instability can cause unwanted flicker

Method used

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  • Dimming of LED driver
  • Dimming of LED driver
  • Dimming of LED driver

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0025] figure 1 , figure 2 , image 3 with Figure 4 An LED driver circuit including a resonant DC-DC converter is depicted. A resonant DC-DC converter includes a switching circuit coupled to the resonant circuit, and a rectifier circuit coupled to the resonant circuit.

[0026] Such as figure 1 , figure 2 , image 3 with Figure 4 As depicted, the switching circuit of the LED driver circuit comprises a switching circuit, which in the embodiment shown is a half-bridge switching circuit having a converter switch coupled in series between the input voltage terminals 20, 21 10, 11, the input voltage terminals 20, 21 are configured to receive a DC input voltage V B . Each of the switches 10, 11 may be any suitable type of electronic switch, for example a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) switch. The DC input voltage may be generated by rectifying the AC mains voltage with a rectifier circuit, which may be supplemented with a power factor correc...

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PUM

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Abstract

A dimmable LED driver circuit comprises a resonant DC-DC converter coupled to an output circuit. The converter comprises a half bridge or full bridge switching circuit coupled to a resonant circuit. An output of the resonant circuit is rectified and fed to the output circuit. The output circuit may comprise at least one LED series or shunt switch for switching an LED unit on and off. A control circuit controls the switches of the switching circuit at a variable switching frequency. The control circuit is also configured for controlling the switching circuit for amplitude modulating the converter and for pulse-width modulating the converter at a first pulse-width modulation frequency lower than the switching frequency. The control circuit is may further be configured for controlling the switching of the LED switch at a second pulse-width modulation frequency lower than the switching frequency.

Description

technical field [0001] The present invention relates to the field of light emitting diode (LED) drivers, and more particularly to dimming of LED drivers to achieve very low dimming levels. Background technique [0002] LEDs are increasingly used in a variety of lighting applications. Many of these applications require that the LED driver be dimmable to vary the amount of light produced by the LED. Furthermore, in the combination of LEDs producing light of different colors, where the different colors are mixed to obtain light with a certain color temperature, a driver for LEDs of one color or several colors is required to be dimmable. [0003] Existing converters used for dimmable LED driver purposes are mainly hard-switching converters. The use of hard-switching converters has the disadvantage that hard-switching converters do not have high efficiency and they generate relatively high levels of electromagnetic interference (EMI). [0004] The relatively low efficiency of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B33/08H05B44/00
CPCH05B33/0815Y02B20/346Y02B20/348H05B33/0818H05B45/39H05B45/327Y02B20/30H05B45/3725Y02B20/40
Inventor J·斯内尔滕G·W·范德文恩
Owner SIGNIFY HLDG BV
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