VR11.1, 4-Phase PWM Controller with
Light Load Efficiency Enhancement and
Load Current Monitoring Features
The ISL6334B, ISL6334C control microprocessor core
voltage regulation by driving up to 4 interleaved synchronousrectified
buck channels in parallel. This multiphase
architecture results in multiplying channel ripple frequency
and reducing input and output ripple currents. Lower ripple
results in fewer components, lower cost, reduced power
dissipation, and smaller implementation area.
Microprocessor loads can generate load transients with
extremely fast edge rates and require high efficiency at light
load. The ISL6334B, ISL6334C utilizes Intersil’s proprietary
Active Pulse Positioning (APP), Adaptive Phase Alignment
(APA) modulation scheme, active phase adding and
dropping to achieve and maintain the extremely fast
transient response with fewer output capacitors and high
efficiency from light to full load.
The ISL6334B, ISL6334C is designed to be compliant to
Intel VR11.1 specifications. It accurately reports the load
current via IMON pin to the microprocessor, which sends an
active low PSI# signal to the controller at low power mode.
The controller then enters 1- or 2-phase operation with diode
emulation option to reduce magnetic core and switching
losses, yielding high efficiency at light load. After the PSI#
signal is de-asserted, the dropped phase(s) are added back
to sustain heavy load transient response and efficiency.