RT9245B is a multi-phase buck DC/DC controller
integrated with all control functions for AMD K8 CPU. The
RT9245B could be operated with 2, 3 or 4 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.
RT9245B implements both voltage and current loops to
achieve good regulation, response and power stage
thermal balance.
RT9245B applies the DCR sensing technology newly. The
RT9245B extracts the ESR of output inductor as sense
component to deliver a precise load line regulation and
good thermal balance for next generation processor
application.
Current sense setting, droop tuning, VCORE initial offset
and over current protection are independent on
compensation circuit of voltage loop. The feature greatly
facilitates the flexibility of CPU power supply design and
tuning. The DAC output of RT9245B supports AMD K8
6-bit VID, precise offset 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. The RT9245B comes to a small footprint
package TSSOP-28.