The uP9557 is a 2/1-phase synchronous-rectified buck controller specifically designed to work with 2.5V~25V input voltage and deliver high quality output voltage for high performance graphic processor power. This device has integrated 5V MOSFET driver and bootstrap switch to save the external component count. This part adopts proprietary RCOTTM (Robust Constant On-Time) control topology, providing flexible selection of output LC filter and excellent transient response to load and line change.
The uP9557 supports NVIDIA Open Voltage Regulator Type-2C with PWMVID feature. The operating mode is controlled by power saving input (PSI). The output voltage is controlled by PWMVID input. The PWMVID input is buffered and filtered to generate accurate reference voltage, and the output voltage is precisely regulated to the reference voltage input. This device uses low-side MOSFET RDS(ON) current sensing technique for phase current balance and phase valley current limit. It also provides resistor-strap selectable operating parameters, such as switching frequency, soft-start slew rate, soft-stop function and current limit threshold.
This device provides comprehensive protections, including over voltage protection, under voltage protection, phase current limit, over temperature protection and PVCC under voltage lockout. The uP9557 is available in WQFN3x3- 20L package.