A high efficiency current source driver with negative gate voltage for buck voltage regulators

In this paper a novel current source driver (CSD) for power MOSFETs is proposed. The proposed CSD alleviates the gate current diversion problem of the CSDs in previous work by clamping the gate voltage to a negative value. Therefore, the proposed driver is able to turn off the MOSFET much faster with a higher effective gate current. The idea presented in this paper can also be extended to other CSDs to improve the efficiency further at high output currents. The experimental results verify the benefits of the proposed CSD. For buck converter with 12 V input at 1 MHz, the proposed driver improves the efficiency from 80.5% using the previous CSD to 82.5% (an improvement of 2%) at 1.2 V/30 A, and at 1.3 V/30 A output, from 82.5% to 83.9% (an improvement of 1.4%).