Linear multi-channel LED constant-current drive circuit

Abstract

The invention provides a linear multi-channel LED constant-current drive circuit. The linear multi-channel LED constant-current drive circuit comprises a voltage input module, an LED module, a plurality of power tubes, a multi-channel current detection module, a constant current control module and a channel selector at least. The LED module is connected to the voltage input module; each level of LED strips are connected with one power tube, and constant current is achieved by adjusting the current of each power tube; the multi-channel current detection module is connected with each power tube and used for detecting the current of each level of LED strips; the constant current control module is connected with the multi-channel current detection module and used for adjusting the output of the power tubes to make the current constant; the channel selector is connected with the multi-channel current detection module. The forward-direction driving voltage VF of the LED strips will not be limited by preset design requirements for chips any more, larger application design flexibility can be achieved, waveform deformation caused by switching motion of adjacent switches is avoided, and simple, effective and direct control can be better achieved.

Description

technical field [0001] The invention relates to the technical field of LED drive control, in particular to a linear multi-channel LED constant current drive circuit. Background technique [0002] LED is a semiconductor electronic component that can emit light. This electronic component can only emit red light with low luminosity in the early days. With the continuous advancement of technology, it has now developed to the extent that it can emit visible light, infrared rays and ultraviolet rays. Big improvement. LED has the advantages of high efficiency, long life, unbreakable, high switching speed, high reliability, etc. that traditional light sources cannot match, and has been widely used in the fields of indicator lights, displays and lighting. [0003] Due to the unidirectional conduction characteristics of LED, when the reverse voltage is applied to both ends of the LED, the LED lamp is in the reverse dead zone and cannot emit light; when the reverse voltage is too larg...

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Problems solved by technology

[0009] But whether it is 1) the waveform control of the detection voltage or 2) the frequency and period control of the detection input voltage, it needs to be realized by an external detection circuit, at least there must be a dedicated pin on the control chip to input this The signal of the external detection circuit; in addition, in the case of changing the LED light string, it is necessary to change the external control signal by adjusting the external resistor, so as to realize the switch conduction time and its corresponding input voltage and the preset LED light string Corresponding to the positive drive voltage of the current, which is the basic limitation of this type of control chip

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