Si9123

Si9123 is a dedicated half-bridge controller IC ideally suited to fixed telecom dc-dc converter applications where high efficiency is required at low output voltages (e.g. <3.3 V). Designed to operate within the voltage range of 12-72 V and withstand 100 V, 100 ms transients, the IC is capable of controlling and directly driving both primary side MOSFET switches of a half-bridge circuit.

High conversion efficiency is achieved by use of synchronous rectifying MOSFET transistors in the secondary. Due to the very low on-resistance of the secondary MOSFETs, a significant increase in the efficiency can be achieved as compared with conventional Schottky diodes for today's low output voltages. On-chip control of the dead time delays between the primary and secondary signals keep efficiencies high and prevents accidental destruction of the power transformer or wasted energy from self timed approaches. Such a system can achieve conversion efficiencies well in excess of 90%.