Self-adaptive adjustment three-channel colored lamp LED constant current driving circuit and method

Abstract

The embodiment of the invention discloses a self-adaptive adjustment three-channel colored lamp LED constant-current driving circuit and method. The circuit comprises a decoder, a two-phase non-overlapping circuit and an LED constant-current driving circuit; the decoder is used for judging the number of lightened channels according to a first input signal and generating a first switch control signal and a second switch control signal; the two-phase non-overlapping circuit is used for modulating the first switch control signal into a first two-phase non-overlapping signal and a second two-phase non-overlapping signal, and modulating the second switch control signal into a third two-phase non-overlapping signal and a fourth two-phase non-overlapping signal; and the LED constant current driving circuit is used for controlling the on / off of the LED according to the second input signal, and outputting current according to the first two-phase non-overlapping signal, the second two-phase non-overlapping signal, the third two-phase non-overlapping signal and the fourth two-phase non-overlapping signal to control the brightness of the LED.

Description

technical field [0001] The present invention relates to the field of integrated circuit design. More specifically, it relates to a constant-current drive circuit and method for adaptively adjusting three-channel color lamp LEDs. Background technique [0002] The block diagram of conventional LED constant current drive circuit is as follows: figure 1 As shown, the three-channel colorful LED constant current is independent, and the constant current is generated by the reference current. The constant current source of each channel is fixed at ILED, which cannot be adjusted and controlled. When a single red light, green light or blue light is on, the whole three-channel colored light outputs one ILED current, and the brightness is the darkest; when two of the red, green and blue lights are on, the whole three-channel colored light outputs two ILED currents , the brightness is medium; when the red light, green light and blue light are all on, the whole three-channel colored lig...

AI Technical Summary

Problems solved by technology

Therefore, for this independent constant current driven three-channel colored light, the three channels are independent of each other, resulting in different color-mixed three-channel colored lights with different LED constant current sums and large brightness differences.

However, adjusting the duty ratio of the three-channel PWM to adjust the continuous output of the mixed color light through the algorithm will cause the problem that the final mixed color of the lamp bead cannot reach 256x256x256=16777216 colors.

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