LM393N integrated Circuits (ICs)

A TMOS power FET, Q1, and an LM393N comparator provide a high-efficiency rectifter circuit. When VA exceeds VB, U1's output becomes high and Q1 conducts. Conversely, when VB exceeds VA, the comparator output becomes low and Q1 does not conduct.

The forward drop is determined by Q1's on resistance and current I. The MTH40N05 has an on resistance of 0.028 Ω; for I = 10 A, the forward drop is less than 0.3 V. Typically, the best Schottky diodes do not even begin conducting below a few hundred mV.