The ISL6364A is a dual PWM controller; its 4-phase PWMscontrol the microprocessor core or the memory voltageregulator,
while its single-phase PWM controls the peripheralvoltage regulator for graphics, system agent, or processor I/O.
The ISL6364A utilizes Intersil’s proprietary Enhanced ActivePulse Positioning (EAPP) modulation scheme to achieveextremely
fast transient response with fewer output capacitors.
The ISL6364A is designed to be compliant to Intel VR12/IMVP7specifications. It accurately monitors the load current via
theIMON pin and reports this information via the IOUT register tothe microprocessor, which sends a PSI# signal to the
controllerat low power mode via SVID bus. The controller enters 1 or2-phase operation in low power mode (PSI1); in the ultra
lowpower mode (PSI2,3), it operates in single phase with diodeemulation option. In low power modes, the magnetic core
andswitching losses are significantly reduced, yielding highefficiency at light load. After the PSI# signal is de-asserted,
thedropped phase(s) are added back to sustain heavy loadtransient response and efficiency. In addition, the ISL6364Afeatures
auto-phase shedding to optimize the efficiency fromlight to full load for Greener Environment without sacrificingthe transient
performance.
Today’s microprocessors require a tightly regulated output voltageposition versus load current (droop). The ISL6364A senses
theoutput current continuously by measuring the voltage across adedicated current sense resistor or the DCR of the
outputinductor. The sensed current flows out of the FB pin to develop aprecision voltage drop across the feedback resistor for
droopcontrol. Current sensing also provides information forchannel-current balancing, average overcurrent protection
andindividual phase current limiting. The TM and TMS pins sense anNTC thermistor’s temperature, which is internally digitized
forthermal monitoring and for integrated thermal compensation ofthe current sense elements of the respective regulator.
The ISL6364A features remote voltage sensing and completelyeliminates any potential difference between remote and
localgrounds. This improves regulation and protection accuracy. Thethreshold-sensitive enable input is available to
accuratelycoordinate the start-up of the ISL6364A with other voltage rails.