High-speed Current Sampling Circuit Designed for COT Applications

A high-speed current sampling circuit is designed for a COT (Constant On Time) Buck converter. A charge pump and LDO (Low Dropout Regulator) are used to power the circuit, and the circuit is able to operate properly during soft-start, protection phase, and high duty cycle while ensuring a high bandwidth. The simulation results show that the circuit can operate normally at a Buck converter switching frequency of 1.6MHz and a duty cycle of 95%, with a gain of 26.6dB and a -3dB bandwidth of 13.42MHz, enabling fast and loss-free sampling of current information.