Multichannel constant-current control circuit applicable to LED driver

Abstract

The invention discloses a multichannel constant-current control circuit applicable to an LED driver, comprising a single output constant-current source and a plurality of channels of output circuits.The multichannel constant-current control circuit is characterized in that each output circuit comprises a current equalizing circuit, a current equalizing control circuit and a load consisting of a plurality of LED lamps; the input of each channel of current equalizing control circuit is from a sampling signal of the sampling resistor to output current, and becomes a public connecting wire afterbeing converted by the current equalizing circuit; the public connecting wire is connected with the other channels to form a current equalizing bus; each channel of current sampling signal and the current equalizing bus voltage are compared and adjusted in the current equalizing control circuit; and an output signal of the current equalizing control circuit can control the size of impedance of a liner adjusting tube of the corresponding current equalizing circuit, then control the size of each channel of current and realize current equalization. The multichannel constant-current control circuit has simple circuit structure and low cost, and is applicable to standard multichannel constant current control of the rear stage of a single-channel constant current power supply.

Description

technical field [0001] The invention relates to a multi-channel constant current control circuit of an LED driver. Specifically, it should be a constant current drive circuit for LEDs, which can realize the current sharing technology among multiple LED loads when multiple LED loads are used in parallel. Background technique [0002] For the application of LED multi-channel constant current control, the most commonly used solutions are: 1. Constant voltage module + multi-channel non-isolated DC / DC constant current circuit (such as BUCK circuit); 2. Voltage adjustable voltage regulator module + multi-line linear Adjust the constant current circuit. [0003] For the first option, refer to figure 1 , the output of the constant voltage module is used as the input of multiple constant current circuits, and each constant current circuit is independently controlled by constant current, which can easily ensure the current sharing of multiple output currents. However, since each co...

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Problems solved by technology

Although the circuit cost of this solution is low and the current sharing performance of each channel is good, the voltage-adjustable pre-stage voltage stabilization module that can realize the above-mentioned voltage following control generally does not have a ready-made standard power supply for selection, and requires custom development, which is expensive in design. For products that require safety certification, because the certified standard constant voltage or constant current power supply cannot be selected, an additional expensive certification fee is required

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