HYSEMi Launches HYC3688H, A Highly Integrated GaN-on-Chip Solution

As domestic GaN power chip technology shifts toward high-integration SoC architectures, HYSEMi has introduced the innovative HYC3688H. Targeted at USB PD chargers, laptop adapters, and flat-panel TV power supplies, this chip uniquely integrates a PWM controller, lossless SenseFET current sensing, and a 700V enhancement-mode GaN (DGaN) power FET within a single DFN 6×8-30L package. This 3-in-1 flyback architecture eliminates the traditional separation between control and power stages, significantly reducing peripheral component counts and layout inductance, thereby providing robust hardware support for achieving extreme power density in compact designs.

The hardware design of the HYC3688H optimizes efficiency, reliability, and EMI performance. Unlike traditional flyback designs that require high-power shunt resistors, the HYC3688H utilizes an internal SenseFET for lossless current sampling, eliminating the heat and power losses associated with shunt resistors while streamlining the Bill of Materials (BOM). The chip features high-voltage startup, a wide VCC operating range of 5V–80V, and an integrated LDO for stable controller power. To address EMI challenges inherent in high-frequency GaN switching, the chip incorporates HYSEMi's proprietary D-GaN driving technology with adjustable switching speeds, allowing engineers to tune drive edges at the silicon level to suppress electromagnetic radiation. Furthermore, it integrates seamlessly with HYSEMi’s synchronous rectification (SR) chips, supporting CCM, QR, and DCM modes for optimal efficiency across all operating conditions, and includes a comprehensive hardware protection suite against transformer saturation, brown-out, output/VCC overvoltage, overload, and thermal runaway.

The mass production of the HYC3688H provides a benchmark for portable, high-performance charging terminals. It has been successfully implemented in UGREEN’s "45W GaN Fast Charger". Due to the 3-in-1 design, UGREEN was able to achieve high power density in a finger-sized form factor while significantly reducing the number of external components. This integration shortens R&D and debugging cycles for manufacturers and accelerates the industry-wide transition toward miniaturized, high-efficiency, and environmentally friendly consumer electronic adapters.