LED driving circuit

Abstract

The invention discloses an LED driving circuit. The LED driving circuit is connected with an LED array, wherein the LED array is an N-dimensional square matrix, and the N is a natural number which is larger than one. The LED driving circuit comprises a current source module, a bleeder circuit module, a comparator circuit module, a logic control module and a switch module, wherein the current source module is used for providing a constant-current power source for the LED array, the bleeder circuit module is used for carrying out voltage division sampling on input voltage, and outputting a plurality of sets of sampled voltage, the comparator circuit module is used for comparing reference voltage with the sampled voltage, and outputting a plurality of sets of comparison signals correspondingly, the logic control module is used for carrying out logical operation on the basis of the comparison signals, and outputting a logic voltage sequence, and the switch module is used for having on-off control over the LED array according to the logic voltage sequence. According to the LED driving circuit, when a switching tube is connected, the switching tube works in a linear zone, power consumption of the switching tube is reduced, and conversion efficiency is improved; according to a simulation result, the power factor of the LED driving circuit can be more than 99%, and the conversion efficiency of the LED driving circuit is about 90%.

Description

technical field [0001] The invention belongs to the field of LED lighting drive control, in particular to an LED control drive circuit with high conversion efficiency and high power factor. Background technique [0002] As a new type of solid-state light source, LED has been widely used in various fields, especially the lighting field, due to its high luminous efficiency and long life. LED has a fixed conduction voltage, and its luminous brightness is closely related to conduction current, so if a series LED is driven, the driving voltage must reach the sum of the total forward conduction voltage of the entire LED light string, and it needs a constant current control. [0003] Traditional LED drivers are generally divided into two types, that is, switching pulse width modulation or switching pulse frequency modulation (PWM, PFM). The conversion efficiency of this control method can be relatively high, but the circuit required is more complicated and the cost relatively hig...

AI Technical Summary

Problems solved by technology

However, there are two problems with this method. One is that the size of the LED current is determined by the reference voltage and the negative feedback circuit composed of the operational amplifier and the NMOS tube, so there is a certain deviation.

Another problem is that the current of each string of LEDs flows to the ground through the NMOS tube working in the saturation area, and the on-resistance of the NMOS tube in the saturation area is larger than that of the NMOS tube in the linear area, so there is power consumption in the NMOS tube, which reduces the conversion efficiency

[0006] In summary, the existing technology has problems in terms of conversion efficiency, power factor and reliability

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