A New Current-Source Gate Driver for a Buck Voltage Regulator

A new current-source gate drive circuit is proposed for a synchronous buck voltage regulator (VR). The proposed driver can drive two MOSFETs independently with different drive currents for optimal design. Furthermore, the new drive circuit can achieve 1) significant switching loss reduction; 2) gate energy recovery; 3) reduced body diode losses and reverse recovery losses; 4) ZVS of all the drive switches. The improved driver using integrated inductors is also presented for a buck VR to reduce the number of magnetic cores and the core loss. The experimental results prove that a significant efficiency improvement has been achieved. At 1.5V output, the new driver improves the efficiency from 84% using a conventional driver to 87.3% (an improvement of 3.3%) at 20 A, and at 30 A, from 79.4% to 82.8% (an improvement of 3.4%). Overall, the new driver approach is very attractive from the standpoints of both performance and cost-effectiveness.