Unlock instant, AI-driven research and patent intelligence for your innovation.

Circuits and methods for reducing flicker in an LED light source

An LED driver and circuit technology, applied to circuits and fields for reducing flash in LED light sources, can solve the problems of unpleasant flash, short after-glow period and the like

Active Publication Date: 2015-07-01
TEXAS INSTR INC
View PDF5 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, LEDs emit light based on current passing through the P-N junction and thus do not have afterglow or have an extremely short afterglow period
Therefore, the conduction angle difference caused by the triac can cause a perceptible and unpleasant flickering

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Circuits and methods for reducing flicker in an LED light source
  • Circuits and methods for reducing flicker in an LED light source
  • Circuits and methods for reducing flicker in an LED light source

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0012] A circuit and method for balancing LED (Light Emitting Diode) driving currents are disclosed herein. refer to figure 1 , which is a schematic diagram of an LED lighting system 100 using a dimmer 104 . A dimmer 104 is used to dim a solid state light (SSL) bulb 106 . In the embodiments described herein, the SSL bulb 106 is an LED bulb, wherein the light source emitted by the bulb 106 is produced by the LED 108 . LED bulbs are slightly different from incandescent bulbs: even for a short period after power is removed from the incandescent bulb, the incandescent bulb gets hot and glows afterglow. LEDs, on the other hand, use a P-N junction to emit light, which stops simultaneously after power to the LED is removed. Consequently, LED bulbs have a much shorter time constant than incandescent bulbs, making them difficult to dim. More specifically, the extremely short time constant makes the LED sensitive to its drive current. For example, ripple in the drive current can ca...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

Method and circuits for balancing a first waveform used to drive an LED are disclosed herein. The first waveform has a first cycle with a first amplitude and a second cycle with a second amplitude. An embodiment of the method includes adjusting the first amplitude of the first cycle to match the second amplitude of the second cycle, the result being a second waveform. The LED is driven with the second waveform.

Description

Background technique [0001] Some people are replacing incandescent bulbs with LED bulbs. LED bulbs are drop-in replacements for incandescent bulbs, so users simply unscrew the incandescent bulb from the socket and replace it with an LED bulb. Many incandescent light bulbs are operated by using a dimmer that controls the intensity of the light emitted by the incandescent light bulb. Most dimmers work by using a triac to clip the AC line voltage supplied to an incandescent bulb. For example, a dimmer clips the positive and negative portions of the AC sine wave that is supplying power to an incandescent light bulb. Due to the construction and inherent principles of operation of the triac, the positive and negative parts of the AC voltage that are clipped by the triac are unequal. [0002] The intensity of light emitted by incandescent and LED bulbs is proportional to the current driving the bulb. Therefore, when the positive and negative parts of the sine wave driving the bul...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H05B37/02H05B44/00
CPCH05B33/0848H05B33/0815H05B45/14Y02E10/50H05B45/3725H05B45/10H02S30/20B64G1/222B64G1/44B64G1/66H01Q1/08H01Q1/288H01Q15/161
Inventor 蒂莫西·罗伊·沙利文丹尼尔·罗斯·赫林顿
Owner TEXAS INSTR INC