Efficiency enhancement and EMI suppression via dynamically adjustable gate driving strength

In this paper, a gate driver IC with dynamically adjustable driving strength is introduced with the goal of improving light load efficiency and conducted electromagnetic interference (CEMI). By continuously adapting the gate driving strength to the output current load of the converter, it is possible to minimize the combined effects of the gate drive loss and the converters switching loss. Furthermore, by dynamically adjusting the gate driving strength (and subsequently the output resistance, Rout) at the arrival of each gate pulse, a reduction in conducted EMI can be realized with little degradation in converter efficiency. A segmented gate driver is designed and fabricated in the AMS 0.35μm 40V HVCMOS process. A 3.5% efficiency improvement at light load is achieved. Further experimental results indicate up to a 7dBμV improvement in peak CEMI between 20MHz and 30MHz.