A dimmable led lighting drive circuit

Abstract

The invention discloses a dimmable LED (Light-emitting Diode) illumination drive circuit based on a silicon-controlled dimmer. The drive circuit comprises the silicon-controlled dimmer and a rectifier bridge, wherein the silicon-controlled dimmer and the rectifier bridge are sequentially connected with an input signal; an output of the rectifier bridge is connected with a silicon-controlled phase detection module; an output of the silicon-controlled phase detection module is connected with input ends of a pulse generator and a LOG curve generator; an output end of the LOG curve generator is connected with an input end of a sample-and-hold module; an output end of the pulse generator is connected with a control end of the sample-and-hold module; an output end of the sample-and-hold module is connected with an input end of a voltage controlled current source; and an output of the voltage controlled current source is connected with an LED load, and controls the current on the LED load. The drive circuit is high in dimming linearity, suitable for the human eye feeling, and high in dimming precision without delay, and can eliminate a wave on a control signal of the voltage controlled current source.

Description

technical field [0001] The invention relates to a driving circuit for LED lighting, in particular to a driving circuit capable of performing linear dimming on an LED lighting device. Background technique [0002] LED is the abbreviation of English LightEmittingDiode, which means light-emitting diode. It is a solid-state semiconductor device that can convert electrical energy into visible light. It can directly convert electricity into light. Because of its semiconductor light-emitting principle, a DC drive is required, so LED lighting equipment needs to be driven by a drive circuit. [0003] There is a kind of existing LED lighting driving circuit based on the dimming of the thyristor dimmer, such as figure 1 The block diagram of the circuit, including the thyristor dimmer, is connected to the phase detection module through the rectifier bridge. Through the phase detection module, the control phase of the thyristor is converted into a square wave signal of power frequency, ...

AI Technical Summary

Problems solved by technology

[0004] In fact, although this traditional dimming method linearly changes the input current of the LED lamp, the brightness of the LED lamp perceived by the human eye does not change linearly, which does not meet the sensory requirements of the human eye, and the dimming process is unnatural. , not soft, there will be a feeling of brightness jumping in severe cases

At the same time, the traditional dimming method needs to rectify a power frequency square wave signal into a DC signal. In order to reduce the ripple on the DC signal and improve the stability of the LED lighting drive current, an RC filter with a very low bandwidth is required. Therefore, the dimming response speed is very slow, and there will be a long delay in the brightness of the LED lamp when adjusting the phase of the controllable dimmer, and it will affect the dimming accuracy

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