STMicroelectronics Introduces Miniature High-Efficiency Synchronous Rectifier Controller
2026-01-29
STMicroelectronics recently launched the SRK1004 series synchronous rectification controller, which can save space and improve energy efficiency for the secondary circuit of active clamp, resonant, and quasi resonant flyback (ACF, AHB, QR) converters in product equipment such as chargers, power adapters, and switching power supplies. This microchip, measuring only 2mm x 2mm, replaces SRK1001 with a new, more energy-efficient and robust shutdown algorithm.
The SRK1004 series has six products, offering two MOSFET gate drive options: logic level and standard level. There are two options for turn off delay: 25ns and 150ns, to compensate for drain inductance. This series of controllers is suitable for active clamp, resonant, and quasi resonant flyback topologies, and has a built-in conduction window circuit to prevent accidental switching operations. The controller outputs a pulling current of up to 1.6A to the gate and a filling current of 0.6A. At the same time, a switching frequency of 500kHz enables compact and low-cost design.
SRK1004 adopts a robust and reliable semiconductor on insulator (SOI) manufacturing process, which can control MOSFET switches in high and low side circuit configurations. It is equipped with up to 190V drain source voltage detection input pins and compatible with 4V to 36V wide voltage power supplies. The low side configuration is powered by a converter output, while the high side configuration is powered by a transformer, without the need for a dedicated auxiliary power supply, minimizing material costs. The SRK1004 internal linear regulator provides power to the chip's internal circuits and gate drivers, and can also supply power to off chip circuits through output pins.
STMicroelectronics offers six evaluation boards, EVLSRK1004A-F, to help developers quickly initiate new projects and select the most suitable SRK1004 product model for converter circuits and MOSFETs.
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