Multi-channel LED (Light Emitting Diode) constant current control circuit and LED light source control system

Abstract

The invention discloses a multi-channel LED (Light Emitting Diode) constant current control circuit, which comprises a power supply module, a booster module, a DC / DC (Direct Current / Direct Current) control module, an LED string module, a constant current adjusting module and a feedback control module, wherein an input end of the booster module is connected with the power supply module; an output end of the booster module is connected with an input end of the constant current adjusting module through the LED string module; the feedback control module is connected with a feedback input end of the DC / DC control module and respectively connected with an output end and a control end of the constant current adjusting module; and a driving output end of the DC / DC control module is connected with a control end of the booster module. The invention further discloses an LED light source control system, which comprises the multi-channel LED constant current control circuit. The multi-channel LED constant current control circuit disclosed by the invention has the advantage as follows: the constant current control precision is high; through adjustment of the current of each LED string, the currents of the LED strings are equal to each other, so that the illumination brightnesses of the LED strings are equal to each other; the uniformity of the LED illumination brightnesses is enhanced; and the multi-channel LED constant current control circuit is suitable for any electronic system using constant current control.

Description

technical field [0001] The invention relates to the technical field of integrated circuit design, in particular to a multi-channel LED constant current control circuit and an LED light source control system. Background technique [0002] As a green light source with low power consumption, LED is widely used in the field of lighting and backlight display. It can be known from the volt-ampere characteristics of the LED that the LED current has an exponential relationship with the voltage, and a small voltage change will cause a large current change, and the current directly determines the brightness of the LED. Therefore, in order to keep the brightness of the LED stable, a constant current must be used. mode, not constant voltage mode. [0003] In the prior art, when the number of LEDs is small, a series connection is usually used, such as figure 1 As shown, the current flowing through each LED is equal, so the brightness is consistent. The advantage of this structure is t...

AI Technical Summary

Problems solved by technology

There are usually two ways of current sampling: the first way is as figure 2 As shown, only the current of one of the LED strings is sampled, which can ensure that the current of the sampled LED string is constant, but the current of each LED string is inevitably different, so the brightness of each LED string is inconsistent. phenomenon; the second way is as image 3 As shown, the sampled current is the sum of the currents of all LED strings. This structure can ensure that the sum of the currents of all LED strings remains constant, but it still cannot solve the problem of current differences between LED strings.

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