A circuit and method for eliminating LED stroboscopic flicker and LED driving circuit

Abstract

The invention discloses a circuit and method for eliminating LED stroboflash and an LED drive circuit. The circuit for eliminating the LED stroboflash is applied to the LED drive circuit. The circuit for eliminating the LED stroboflash comprises a filter circuit and a controllable device with a constant-current characteristic. With regard to an LED driver, when a load connected with the LED driver has a current source characteristic, the current which flows through the load is direct current without alternating components, and output voltages of the LED driver is pulsating voltages with a few alternating components. Therefore, the controllable device is used for providing constant current for the LED load, then the current which flows through the LED load is the direct current without the alternating components, therefore the LED stroboflash is eliminated, the filter circuit is used for filtering the alternating components of the output voltages, and then the voltages on the LED load are also direct current voltages without the alternating components.

Description

technical field [0001] The present application relates to the technical field of power electronics, in particular to a circuit, method and LED driving circuit for eliminating LED flicker. Background technique [0002] LED (Lighting Emitting Diode, light-emitting diode) has the characteristics of energy saving, environmental protection, high efficiency, and safety. Therefore, it is widely used in lighting occasions such as landscapes, street lights, and electronic product backlights. [0003] Generally, LED drive circuits use constant current to drive LED loads. Such as Figure 1a As shown, the traditional LED driving circuit includes LED driver 1 and output capacitor C out , the LED driver 1 converts the AC mains power (operating frequency is 50Hz) into a DC power supply to the LED load, specifically, the LED driver 1 converts the AC mains power V in After rectification, it is converted into direct current and supplied to the LED load. However, since the driving current o...

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Problems solved by technology

However, since the driving current output by the LED driver to the LED load contains an AC component of about 100 Hz, there will be a stroboscopic phenomenon that the human eye can perceive when the LED emits light.

[0004] See Figure 1b ,show Figure 1a The main working waveform diagram in the circuit shown, assuming that the power factor of LED driver 1 is 1, the AC mains V in When it is a sine wave, the input current i of the LED driver in is a sine wave, the instantaneous input power P in is the pulsating power in the form of sine square, and the output power P o is flat power, the voltage across the LED load can be regarded as a flat voltage, and the current i flowing through the LED load LED It contains an AC component of about 100Hz, which leads to the stroboscopic phenomenon that the human eye can perceive. Therefore, a circuit that can eliminate the LED stroboscopic is urgently needed

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