Compliant with IMVP8™, the ISL95855 provides a complete power solution for Intel microprocessors supporting core, graphics and system agent rails. The controller provides control and protection for three Voltage Regulator (VR) outputs. The VR A output can be configured for 3-, 2- or 1-phase operation. VR B is configurable for 2- or 1-phase operation and VR C supports 1-phase operation. The address options programmable for these three outputs allow for maximum flexibility in support of the IMVP8™ CPU.
https://www.renesas.com/br/zh/products/power-management/computing-power-vrm-imvp/multiphase-controllers/device/ISL95855.html