Patent ID: 8674621
Filing Date: 2014-03-18
Classification: H05B,Y02B

Abstract:
1. A constant current control circuit with multiple outputs for an LED driver, the circuit comprising: a single-output constant current power supply; and multiple output circuits, each output circuit comprising: wherein the current sharing circuit further comprises a current sampling resistor and a linear regulator with an output of the current sharing circuit connected with an input terminal of the current sharing control circuit and with an input signal of each current sharing control circuit connected to an output current sampling signal of the respective sampling resistor; wherein a common terminal of each current sharing control circuit is connected together to form a current sharing bus, and each current sampling signal and the current sharing bus signal representing an average current signal derived from a node of the current sharing bus are compared and adjusted, without input of an external reference voltage, through the current sharing control circuit so that the output signal of the corresponding current sharing control circuit can control an impedance of the linear regulator, and then control the current of each output to make sure the current output by each circuit is equivalent to one another; and wherein the current sharing control circuit comprises an amplifier with a positive input terminal of the amplifier connected with a current sharing bus and a resistor in series, and then connected with its negative input terminal of the amplifier and the sampling terminal of sampling resistor, the output terminal of the amplifier is connected with the control terminal of the linear regulator directly or by connecting with an output resistor in series.