This is the circuit diagram of low forward-drop rectifier. A TMOS power FET (Q1) and a LM393 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 doesn’t conduct.
The forward drop is determined by Q1’s on resistance and present I. The MTH40N05 has an on resistance of 0.028 Ohm; for I = 10 A, the forward drop is much less than 0.3 V. Usually, the most effective Schottky diodes do not even start conducting beneath several hundred mV.
Download MTH40N05 and family datasheet from the following link:
