Power Supply Lightning Protection via Surge Bypass

A gas discharge tube is introduced as an intermediary protective device between the power input and the active bridge rectifier. During normal operation, the gas discharge tube remains non-conductive and does not affect the efficiency of the MOSFET-based rectifier. When lightning strike occurs, the gas discharge tube ionizes and provides a low-impedance bypass path for the surge current, protecting the MOSFETs from overvoltage and overcurrent damage.

The invention converts the harmful lightning surge energy into a beneficial protective action by utilizing the gas discharge tube's ability to ionize and conduct under high-voltage stress. The lightning energy that would otherwise destroy the MOSFETs is redirected through the gas discharge tube, which safely dissipates the energy through controlled ionization and subsequent current conduction, thereby transforming a destructive force into a protective mechanism.

The invention combines two different protective components - a gas discharge tube and a varistor - into a composite protective circuit. The gas discharge tube provides primary protection by ionizing and conducting the majority of the surge current at high voltage levels. The varistor provides secondary protection by clamping residual voltage and protecting against lower-level surges. This composite approach leverages the complementary strengths of both components to achieve superior surge suppression effectiveness.

The surge protection function is segmented into two distinct stages: primary protection handled by the gas discharge tube for high-voltage lightning surges, and secondary protection handled by the varistor for residual voltage and lower-level surges. This segmentation allows each component to operate in its optimal performance range, with the gas discharge tube handling the bulk of the energy dissipation and the varistor providing fine-tuned voltage clamping.