RT9248A

The RT9248A is a cost-effective multi-phase buck DC/DC controller integrated with all control functions for GHz CPU VRM. The RT9248A controls 2 or 3 buck switching stages operating in interleaved phase set automatically. The multiphase architecture provides high output current while maintaining low power dissipation on power devices and low stress on input and output capacitors. The high equivalent operating frequency also reduces the component dimension and the output voltage ripple in load transient.

RT9248A controls both voltage and current loops to achieve good regulation, response & power stage thermal balance. Precise current loop using R_DS(ON) as sense component builds precise load line for strict VRM DC & transient specification and also ensures thermal balance of different power stages. The settings of current sense, droop tuning,
VCORE initial offset and over current protection are independent to compensation circuit of voltage loop. The feature greatly facilitates the flexibility of CPU power supply design and tuning.

The DAC output of RT9248A supports VRM9 & VRD10 by VID125 multi-level input, precise initial value & smooth VCORE transient at VID jump. The IC monitors the VCORE voltage for PGOOD and over-voltage protection. Soft-start,over-current protection and programmable under-voltage lockout are also provided to assure the safety of microprocessor
and power system.