Digital assistant current sensor for PWM DC-DC converter with segmented output stage

A digital assistant sensor in PWM converter with segmented output stage is proposed in this paper. The output stage is segmented according to the load current, especially segmented in light loads condition. Conversional current sensor in a power integrated converter is not accurate enough for the light loads. A segmented current sensor (SCS) allying a time digital converter (TDC) is proposed to sensor the load current at light load condition in discontinuous current mode (DCM) in this paper. The SCS detects the load current in continuous current mode (CCM). Hence, refined segmented output stage can be obtained for optimized efficiency. The structure of the proposed digital assistant current sensor is described in this paper. And the PWM converter with the adaptive segmented output stage is designed and simulated in a 0.13μm standard CMOS process. The simulation results show that the maximum efficiency improvement of the proposed converter reaches 8% compared to converter without segment.