LED constant current driving circuit having light modulation function

Abstract

Provided is an LED constant current driving circuit having a light modulation function, belonging to the technical field of semiconductors. The LED constant current driving circuit includes a silicon controlled rectifier light modulation module, a constant current rectifying module, a power factor correction module and a circuit protection module, the silicon controlled rectifier light modulation module changes the conduction delay and conduction angle size by changing the RW resistance value of a light modulation potentiometer, the duty ratio of the current through the LED is changed, and the LED brightness is influenced. The constant current rectifying module composed of a high reverse withstand voltage constant current device and a high-voltage diode simplifies the structure of a conventional LED driving circuit, so that the rectification function and the constant current function are combined, and the LED lamp string is driven by directly connecting with the mains supply without the need for other branch constant current devices; and a high-molecular PPTC prevents the current through the LED from being too large, a high-voltage bleeder circuit protects the LED lamp string from being damaged due to transient high voltage. The rectification, constant current, and light modulation functions are combined, the structure of the driving circuit is simplified, the miniaturization of the driving system can be realized, and the cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and in particular relates to an LED constant current drive circuit with dimming function. 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...

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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