The RT9241A/B is a two-phase buck DC/DC controller
integrated with all control functions for high performance
processor VRM. The RT9241A/B drives 2 buck switching
stages operating in 180 degree phase shift. The twophase
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.
RT9241A/B regulates both easily set voltage and current
loops. Precise current sharing for power stage is achieved
by differential input current sense and processing circuit.
The settings of current sense, droop tuning 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 RT9241A/B uses a 5-bit DAC of 1.1V to 1.85V
(25mV/step) output with load current droop compensation
to meet the strict VRM transient requirement. 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.