Constant current control circuit

摘要

A constant current control circuit includes a current source output module and at least two output circuits. Each of the output circuits includes an automatic constant current regulating module, a power transistor drive and control module electrically coupled to automatic constant current regulating module, and a load module formed of one or more LED devices and electrically coupled to a power transistor drive and control module. The constant current control circuit in operation tracks changes in current of each output circuit and regulates the currents of all the output circuits accordingly.

主权项

1. A constant current control circuit, comprising:
a current source output module; and at least two output circuits, each of the output circuits comprising an automatic constant current regulating module, a power transistor drive and control module, and a load module formed of one or more light emitting diode (LED) lamps, wherein, for each output circuit, an input terminal of the automatic constant current regulating module is connected to an output terminal of the current source output module, the power transistor drive and control module is connected to two output terminals of the automatic constant current regulating module, a first terminal of the load module is connected to a first DC power supply PVDD, and a second terminal of the load module is connected to an output terminal of the power transistor drive and control module; and wherein the current source output module has an output terminal, and comprises: a reference current source IBIAS; and a bus current mirror formed of a PMOS transistor M1 and a PMOS transistor M2, wherein sources of the PMOS transistor M1 and the PMOS transistor M2 are connected to a second DC power supply VDD, a gate and a drain of the PMOS transistor M1 are commonly connected to a gate of the PMOS transistor M2, the reference current source IBIAS is connected between the drain of the PMOS transistor M1 and ground, and a drain of the PMOS transistor M2 is connected to the output terminal of the current source output module.