Power FET Gate Charge Recovery for Switching Regulators

The patent recovers gate charge energy that would otherwise be dissipated during each switching cycle. By capturing the energy stored in the gate capacitance of the power FET when the transistor turns off and storing it in a recovery capacitor, the system recovers a substantial portion of the gate charge loss. This recovered energy is then reused to drive the gate in subsequent cycles, significantly reducing the net energy loss at high switching frequencies.

The patent converts the harmful effect of high input voltage causing increased gate charge losses into a benefit. By using the high voltage to charge the gate capacitance and then recovering this energy through the gate charge recovery circuit, the system transforms the energy that would be wasted as heat into reusable energy. This allows the system to maintain high power delivery capability at 12 volts while achieving high efficiency even at elevated switching frequencies.

The patent implements continuous gate charge recovery and reuse throughout the switching operation. The recovery capacitor continuously accumulates gate charge energy from each switching cycle and continuously supplies this recovered energy back to the gate driver. This continuous cycle of recovery and reuse ensures that the beneficial effects of high switching frequency (smaller components, reduced EMI) are achieved without the penalty of increased gate charge losses, maintaining high efficiency at 500 kHz and above.