Internal resistance reducing circuit for MOSFET half-bridge driver

摘要

The circuit reduces the internal resistance of inverting, complementary MOSFET half-bridge drivers on missing supply voltage. To the n-channel MOS transistor (T2) of the half-bridge driver is parallel-connected a pnp-transistor (T3), with the n-channel MOS transistor being of lower power. The connection is such that the pnp-transistor emitter is linked to the drain terminal (D), and its collector is coupled to the source terminal of the n-channel transistor. The base is energised such that, in normal operation, the pnp-transistor does not take up any current, but becomes conductive on reverse voltages.