Brief Comparison of High-Side Gate Drivers for Series Capacitor Buck Converters

This short article is concerned with the floating high-side gate driver suitable for driving the high side MOSFET/IGBT switch in the series capacitor buck converter family or converters with similar topological features. Biasing the high-side driver in series capacitor buck converters presents an engineering challenge. To alleviate the problem, a modified high-side driver with a voltage lift circuit for driving a high-side switch is proposed. The suggested solution, while being simple and low cost, has several benefits over the earlier propositions. The primary advantage of the proposed circuit is that it relies on a regulated supply to recharge its boot capacitor so to properly bias the high-side driver. Moreover, the proposed driver can operate in a wide range of input voltages while self-adjusting the correct voltage lift according to the operating point of a particular phase of the series buck converter. Thus, any number of phases can be implemented, avoiding cross-coupling effects and providing the high-switch with gating pulses of same amplitude.