Design of a transient voltage clamp (TVC) for 4 Switch Buck Boost (4SBB) Converter

This paper presents a new design methodology of the transient voltage clamp (TVC), which operates by controlling inductor current slew rate in 4 switch buck boost converter (4SBB). When 4SBB operates in boost mode, the TVC circuit changes inductor current slew rate during load current step-down to achieve a faster voltage regulation. Due to the slow inductor current slew rate, traditional 4SBB could not respond rapidly to the load current transient. As a result, a large output voltage spike can be occurred during load transient. The specific function of the TVC is to control unused switches when 4SBB operates in boost mode. The main challenge in applying the TVC is how to control unused switches during load current transient. In this paper, how to control the inductor current slew rate and transient response are discussed. The theoretical analysis will be confirmed by the cadence simulation results.