A self powered gate drive circuit for tapped inductor buck converter

This paper proposes a new recovering approach for a tapped inductor buck converter. In the proposed converter, the energy of the leakage inductance is transferred into two capacitors. The capacitors behave like constant power supplies for gate-driver circuits. A voltage source driver is used for driving the high-side MOSFET. For this MOSFET, the optimal design involves a tradeoff between switching loss and gate-drive circuit loss. Also, voltage source driver is used for driving the synchronous-rectifier. For this MOSFET, the optimal design involves a tradeoff between body diode conduction loss and gate-drive circuit loss. The main advantage of the proposed converter is recovering the tapped inductor leakage inductance energy and using it for supplying the gate drive circuit which results in higher efficiency and simplicity of the control circuit. By proper design of inductors, optimized voltage for driving the switches is achieved. The proposed converter is fully analyzed. The presented simulation results verify the principles of operation and show a considerable efficiency improvement. At 1.2 V output voltage and 1 MHz switching frequency, the proposed technique improves the efficiency from 80.6% using a conventional driver to 83.5% (indicating an improvement of 2.9%) at output current of 25A.