Silicon controlled rectifier light modulation scintillation solving method on LED and circuit

Abstract

The invention discloses a silicon controlled rectifier light modulation scintillation solving method on a LED; the method comprises the following steps: detecting a silicon controlled rectifier cut wave angle, and outputting a cut wave angle signal; detecting whether the cut wave angle signal is a threshold signal or not; if yes, start outputting a compensation signal, and controlling a current value on the LED according to the compensation signal. The method detects the cut wave angle information of a silicon controlled rectifier light modulator, compensates the output current according to the cut wave angle information, decreases the LED current down to zero before the silicon controlled rectifier light modulator cut wave has severe asymmetry, thus solving the scintillation problem.

Description

technical field [0001] The present application relates to the field of electronic technology, and in particular to a method and circuit for solving the flickering of LED dimming by silicon controlled rectifiers. Background technique [0002] The LED drive circuit adopts the connection mode of linear drive, such as figure 1 shown. This connection method has the advantages of simple structure, low Electro Magnetic Interference (EMI), compatibility with most thyristor dimmers to realize dimming, and the like. [0003] However, when the traditional linear LED drive circuit is used with a thyristor dimmer, when the conduction angle of the thyristor is small (or the wave cutting angle is large), there will be a flickering problem. The reason for this problem is When the input peak voltage is close to the output LED voltage after wave-cutting rectification by silicon controlled rectifier, serious asymmetry will appear in the wave-cutting of silicon controlled rectifier dimmer, so...

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Problems solved by technology

[0003] However, when the traditional linear LED drive circuit is used with a thyristor dimmer, when the conduction angle of the thyristor is small (or the wave cutting angle is large), there will be a flickering problem. The reason for this problem is When the input peak voltage is close to the output LED voltage after wave-cutting rectification of the silicon controlled rectifier, serious asymmetry will appear in the wave-cutting of the wave-cutting of the silicon-controlled dimmer, so that the peak voltage input after the wave-cutting rectification of the silicon controlled rectifier is aperiodically greater than or less than the output LED voltage (as figure 2 As shown, two peak voltages Vin_pkA and peak voltage Vin_pkB are correspondingly obtained after wave cutting, and Vin_pkA>V LED >Vin_pkB), causing the current on the LED to change drastically aperiodically, and the frequency of the current change at this time is less than the recognition frequency of the human eye, resulting in the phenomenon of flicker visible to the human eye, and due to the dimming effect of different dimmers vary, thus greatly reducing compatibility with TRIAC dimmers

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