Integrated circuit replacing an external integral capacitor and LED constant-current drive circuit

Abstract

The invention discloses an integrated circuit replacing an external integral capacitor, which solves the problems of large volume and high cost caused by externally connecting an integral capacitor with a large capacity value to ensure that the output current is a constant linear current in the prior art. The integrated circuit includes an operational amplifier GM, a drive circuit, a current conversion integrated circuit and a capacitor C. The operational amplifier GM charges / discharges the capacitor C; the current conversion integrated circuit collects a voltage signal of the capacitor C to generate a square wave signal and converts the square wave signal into a voltage with a small step size; the drive circuit determines the output current magnitude according to the voltage, and generates a feedback voltage Vcs as an inverted input signal of the operational amplifier GM. The invention also discloses specific application of a novel LED closed-loop linear constant current control integrated circuit, which is an integrated circuit replacing an external integral capacitor. The invention has advantages of high integration, low cost, long service life and the like.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to an integrated circuit and an LED constant current drive circuit replacing an external integrating capacitor. Background technique [0002] In order to achieve a constant linear current output in various driving circuits in the prior art, a COMP pin is often set on the integrated circuit, and the integrated circuit is externally connected with a UF-level integrating capacitor through the COMP pin to ensure that the output current is a constant linear current. , but due to the large volume of UF-level capacitors and the sharp rise in the price of chip capacitors, the cost of using this traditional method has increased. [0003] Such as figure 1 As shown, in the traditional linear LED drive circuit that integrates the output LED current with an external low-frequency large-capacity capacitor, the IS pin uses the voltage on RCS to compare with the VREF voltage, integrates the COMP...

AI Technical Summary

Problems solved by technology

[0006] For integrated circuits in the prior art, because it is necessary to ensure that the output current is a constant linear current, it is necessary to externally connect a UF-level large capacitor through the COMP pin as an integrated circuit with an integral capacitor to ensure that the output current is a constant linear current, because UF grade capacitors are large in size and cannot be integrated on the chip, resulting in a large circuit system collectively and increasing costs. The present invention provides an integrated circuit that replaces an external integral capacitor, which is used to replace the integral function of UF grade large capacitors so as to ensure The output current of the IC is a constant linear current

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