A new inductorless bipolar gate driver for control FET of high frequency buck converters

摘要

A new inductorless bipolar gate driver for control FET of high frequency buck converters is proposed in this paper. Compared with the conventional unipolar gate driver, the most important advantage of the new gate driver presented in this paper is that it can turn off the power MOSFETs with a negative voltage, which will significantly reduce the turn off time and thus switching loss of the power MOSFETs. In addition, the proposed bipolar gate driver has no inductor in the driver circuit; therefore it can be fully integrated into a chip. Simulation results are provided to validate the benefits of the proposed inductorless bipolar gate driver compared with conventional voltage source driver. A prototype of synchronous buck converter driven by the proposed gate driver was built to verify its functionality and advantages. At 5V input, 1.3V/25A load, in 2 MHz switching frequency, the proposed gate driver increases the efficiency from 75.8% to 77.8%. At 5V input, 1.3V/25A load, in 2.5 MHz switching frequency, the efficiency is improved from 72.9% to 76.5% by the proposed driver. Therefore, the proposed bipolar gate driver is a better choice in high frequency and high current application.