Linear LED drive circuit for silicon controlled dimming

Abstract

The invention relates to the technical field of LED drive circuits, in particular to a linear LED drive circuit for silicon controlled dimming. The technical problems that in the prior art, when overshoot flicker at the turn-on moment is achieved and critical voltage is reached, channels are switched repeatedly to cause switch flicker are solved. The linear LED drive circuit mainly comprises a power source, a silicon controlled switching circuit, a rectifier bridge, an integral circuit and a drive circuit, wherein a silicon controlled drive power circuit is formed by the power source, the silicon controlled switching circuit and the rectifier bridge; the integral circuit comprises a power source potential point and a sampling potential point, wherein the voltage values of the power source potential point and the sampling potential point are reduced in sequence, and the output end of the rectifier bridge is connected to the power source potential point; the drive circuit comprises a switch control and processing circuit, and the switch control and processing circuit controls a first switch transistor of a drive circuit discharge channel and a second switch transistor of a drive circuit LED channel to be connected or disconnected through voltage of the sampling potential point; the switch control and processing circuit comprises a hysteresis comparator and an LED lamp, the input end of the hysteresis comparator is connected to the sampling potential point, and the maximum potential point of the LED lamp is connected with the output end of the rectifier bridge. The invention is used for designing the LED drive circuit.

Description

technical field [0001] The invention relates to the technical field of LED driving circuits, in particular to a linear LED driving circuit for dimming with silicon controlled rectifiers. Background technique [0002] In the LED linear drive structure, the circuit used for thyristor dimming is commonly seen as Figure 12 shown. The thyristor discharge circuit is usually a separate discharge circuit, which discharges through the BLD channel, while the LED current passes through another channel. When the thyristor switch is turned on, because the voltage above the bus voltage is not high enough, the LED channel cannot be turned on. At this time, the BLD channel is turned on to provide the maintenance current of the thyristor switch. As the conduction angle of the thyristor switch increases, when the bus voltage is high enough, the LED channel starts to conduct. Generally, the voltage of VREF1 is set to be lower than the voltage of VREF2 inside the IC, so when the current of t...

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Problems solved by technology

[0009] In view of the above prior art, the purpose of the present invention is to provide a linear LED drive circuit for thyristor dimming, which solves the overshoot flicker at the turn-on moment of the prior art and the switch caused by repeatedly switching channels when the critical voltage reaches Technical problems such as flickering

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