CONSTANT-CURRENT LED DRIVER CIRCUIT AND OUTPUT VOLTAGE ADJUSTABLE CIRCUIT AND METHOD THEREOF

摘要

A constant-current Light Emitting Diode (LED) driver circuit is provided, and the circuit includes: an output voltage adjustable circuit and at least one path of LED load, wherein the output voltage adjustable circuit comprises: a switch converting main circuit, an output characteristic parameter sampling circuit, and an output voltage controller. The output voltage controller is used to adjust the output voltage of the switch converting main circuit according to the variation relationship between the sampling signal output by the output characteristic parameter sampling circuit and the output voltage, determine the adjustive direction of the output voltage magnitude of the switch converting main circuit according to the change of the sampling signal, adjust the magnitude of the output voltage of the switch converting main circuit according to the preset step, and finally make the output voltage equal to the voltage of one path of LED load with the highest voltage or the difference between the output voltage and the voltage of one path of LED load voltage with the highest voltage within the predetermined range. The present solution implements reducing the connection complexity and power dissipation on the base of controlling the multi-path constant-current LED.