Accurate switching loss model and optimal design of a current source driver considering the current diversion problem

A new analytical switching loss model for power MOSFETs driven by Current Source Drivers (CSDs) is presented in this paper. The gate current diversion problem, which commonly exists in CSDs, is analyzed. In addition, the proposed loss model considers the Miller Plateau. The optimal design of current source driver is achieved which minimizes the total power loss for the Buck converter. The experimental result verifies the theoretical analysis. Compared with previous work, the efficiency at 1 MHz with the optimal current source inductor is improved from 86.1% to 87.6% at 1 MHz switching frequency, with 12V input, 1.3V/20A output, and from 82.4% to 84.0% at 1MHz switching frequency, with 12V input, 1.3V/30A output.