Dimmable LED driving circuit

Abstract

A dimmable LED driving circuit belongs to the technical field of a semiconductor. The LED constant-current driving circuit comprises a silicon controlled rectifier dimming module, a constant-current rectification module, a power factor correction module, a filtering module and a circuit protection module, wherein the silicon controlled rectifier dimming module is used for changing conduction delay and the size of a conduction angle by changing a RW resistance value of a dimming potentiometer so that the duty ratio of a current passing through an LED is changed to affect the brightness of the LED; the structure of a traditional LED driving circuit is simplified by the constant-current rectification module comprising a high-reverse voltage-resistant current-constant device, so that the rectification function and the constant-current function are combined, a mains supply can be directly connected without additionally arranging other discrete constant-current devices to drive an LED lamp string; and excessive large current passing through the LED is prevented by using a polymeric positive temperature coefficient (PPTC) thermistor, and the LED lamp string cannot be damaged due to transient high voltage by a piezoresistor Rv. By the LED constant-current driving circuit, the functions of rectification, constant current and dimming are combined, the structure of the driving circuit is simplified, the miniaturization of the driving system can be achieved, and the cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and in particular relates to a dimmable LED driving circuit. Background technique [0002] The constant current source is a commonly used electronic equipment and device, mainly used to protect the entire circuit, even if the voltage is unstable or the load resistance changes greatly, it can ensure the stability of the supply current. The constant current source has been used in electronic circuits. Widely used, such as the drive of LED light strings, etc. The traditional LED lighting driver is generally composed of a rectifier bridge plus one (or more) constant current chips or constant current devices. The constant current device is generally a constant current device similar to a JFET junction field effect transistor structure, with bidirectional conduction The characteristic is that it can achieve the effect of constant current when it works in the forward direction, and it is similar...

AI Technical Summary

Problems solved by technology

The LED lighting drive system includes rectification and constant current two parts, the structure is relatively complex, and the drive system is prone to instantaneous high-voltage surges, does not have the ability to protect large currents, and easily burns out the LED lights

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