Design of novel bootstrap driver used in high power BUCK converter

A novel bootstrap driver suitable for high power buck converter is presented in this paper. With the help of bootstrap driver, the P type power MOSFET used in conventional BUCK converter can be replaced by N type power MOSFET in order to optimize efficiency and area. The proposed bootstrap driver, abandoning conventional level shift circuit, can work properly in a wide power supply range with sufficient protection. The bootstrap driver has been validated with UMC 0.6-µm BCD process based on a monolithic voltage-mode BUCK converter capable of driving up to 3A loads with supply voltage from 8 to 30V. Simulation results demonstrate that the power efficiency is over 84% for load current from 1A to 3A, and the BUCK converter can operate properly under all the application conditions.
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