A new hybrid gate drive scheme for high frequency buck voltage regulators
This paper presents a new hybrid drive scheme for a synchronous buck voltage regulator (VR). The proposed current-source driver is used to drive the control MOSFET to achieve fast switching speed and reduce the switching loss significantly due to the parasitic inductance in addition to gate energy recovery. Conventional voltage driver is used for synchronous rectifier (SR) MOSFET for its simplicity and good immunity and alleviation of dv/dt effect. The experimental results prove the advantages of the new drive scheme and a significant efficiency improvement has been achieved. At 1.3 V output, the new driver improves the efficiency from 82.8% using a conventional driver to 85.6% (an improvement of 2.8%) at 20 A, and at 25 A, from 80.5% to 83.0% (an improvement of 2.5%). The new drive can also be integrated into a standard drive integrated circuit (IC) and replace the conventional voltage drive IC directly. Overall, the new driver scheme is very promising from the standpoints of both performance and cost- effectiveness.