IC Revs Up Performance Of Isolated Converters

Serving to improve the performance of isolated dc/dc converters with voltage outputs down to 1.5V, the IR1176 synchronous rectification IC (SRIC) controls gate drive circuits to minimize losses in secondary-side, isolated converter synchronous rectification MOSFETs. In operation, the SRIC uses a modified PLL to lock the FETs' switching frequency to the primary-side switching action. This allows the secondary-side MOSFETs to be pre-fired with programmable control of turn-on transition lead time, as well as dead time and overlap between gate drive signals. By pre-firing the FETs, parasitic diode conduction is eliminated and all output current is now conducted through the active FET channels.
When used with power FETs, the IR1176 SRIC enhances 1.5V and 1.8V dc/dc converter efficiency ratings—tat 40A, in-circuit efficiency is 85% for 1.5V and 86% for 1.8V output circuits with a 48V input. The SRIC costs $3.50 each/10,000.