STMicroelectronics SRK1004 synchronous-rectifier controller

The STMicroelectronics SRK1004 synchronous-rectifier controller is designed to enhance the efficiency of converters built with silicon or GaN transistors, including industrial power supplies, portable-device chargers and AC/DC adapters.

Capable of withstanding up to 190 V at its sense input, the controller can be connected in a high-side or low-side configuration. Four variants let users avoid complex calculations by optimising their design through device selection, selecting gate-drive voltage between 5.5 and 9 V, with logic-level MOSFETs, standard MOSFETs or GaN transistors. Suitable for non-complementary active clamp, resonant and quasi-resonant (QR) flyback topologies, the controller features a next-generation turn-off algorithm that simplifies operation and saves energy.

The features of this controller enable converters to provide a high output power rating within compact dimensions. The operating frequency can be up to 500 kHz, allowing the use of small magnetic components as well as maximising the benefits of wide-bandgap technology when using GaN transistors. The controller is fabricated in ST’s silicon-on-insulator (SOI) process, to enhance performance while permitting a tiny 2 x 2mm DFN-6L package.

By operating with a supply voltage from 4 to 36 V, the controller can be powered from a variety of standard industrial bus voltages. The wide input-voltage range also provides flexibility to adjust the step-down ratio for optimum efficiency. Also, with fast-acting short-circuit detection built-in, the controller helps build rugged and reliable equipment.