An active current-sensing constant-frequency HCC buck converter using phase-frequency-locked techniques

A hysteresis-current-controlled (HCC) buck converter with active current-sensing and phase-frequency- locked techniques is presented in this paper. The proposed active current-sensing technique can not only consume less power than previous techniques, but also fully sense the inductor current. Although the buck converter is HCC, the switching frequency can be constant due to the devised phase-frequency-locked technique. The proposed converter has been designed and implemented with TSMC 0.35 mum DPQM CMOS processes. It is shown in the experimental results that the HCC buck converter features the following characteristics: 1) up to 800 mA of load current, 2) wide input and output voltage range, 3) high power efficiency, and 4) constant-frequency operation.