An enhanced double current limit technique used in high power BUCK converter

An enhanced double current limit technique suitable for high power buck converter is presented in this paper to protect the converter from damage under any fault condition. The first peak current limit circuit works properly when the output is in minor over load. If the current increases continuously to some amount after the first peak current limit working in major overload or short circuit, the frequency of the buck converter is decreased by the second peak current limit circuit. The duty cycle can decrease below the value normally limited by the propagation delay in this way. The enhanced current limit technique has been validated with UMC 0.6-¿m BCD process based on a monolithic voltage-mode buck converter capable of driving up to 3 A loads with supply voltage from 8 to 30 V. Simulation results demonstrate that the proposed current limit technique can guarantee the buck converter operating properly under any condition without damage.