Self-Adaptive Window Control Technique for Hysteretic Buck Converter with Constant Frequency

A hysteretic buck converter with self-adaptive window controller is presented in this paper. Since the switching frequency of conventioal hysteretic buck converter varies with the input voltage and load current, which might result in severe Electro-Magnetic Interference (EMI), a self-adaptive window control technique is proposed to tackle this problem. The proposed converter is design and fabricated in TSMC 0.35 mu m CMOS process. Simulation and experiment results show that the switching frequency of this converter is held a near constant value when input voltage or load current changes.