Design and implementation of light load energy saving current-limiting circuit

This article presents a current-limiting protection circuit, which is being used in the design of USB power management chip. Compared with the traditional current-limiting protection circuit, its advantage lies in using a constant current source to replace the traditional series sampling resistor to reduce the power consumption generated by the drive circuit. What´s more, on the purpose of energy conservation, it increases the voltage feedback control signal to change the current mirror ratio for reducing the power consumption of the chip itself under the condition of light load. The principle of this current limiting circuit is analyzed theoretically in this article. Meanwhile, the theory is verified by CMOS0.35um process simulation.