DATASHEET
ISL78225 FN7909
Rev 4.00
September 5, 2014 4-Phase Interleaved Boost PWM Controller with Light Load Efficiency
Enhancement Features The ISL78225 4-phase controller is targeted for applications
where high efficiency (>95%) and high power are required. The
multiphase boost converter architecture uses interleaved
timing to multiply channel ripple frequency and reduce input
and output ripple. Lower ripple results in fewer input/output
capacitors and therefore lower component cost and smaller
implementation area. Peak current mode PWM control with adjustable slope
compensation Precision resistor/DCR current sensing 2-, 3-or 4-phase operation Adjustable phase dropping/diode emulation/pulse skipping
for high efficiency at light load The ISL78225 has a dedicated pin to initiate the phase
dropping scheme for higher efficiency at light load by dropping
phases based on the load current, so the switching and core
losses in the converter are reduced significantly. As the load
increases, the dropped phase(s) are added back to
accommodate heavy load transients and improve efficiency. Phase dropping facilitated with companion FET driver
ISL78420 (featuring tri-level input control) Adjustable switching frequency or external synchronization
from 75kHz up to 1MHz per phase Over-temperature/overvoltage protection Input current is sensed continuously by measuring the voltage
across a dedicated current sense resistor or inductor DCR. This
current sensing provides precision channel-current balancing,
and per-phase overcurrent protection. A separate totalizing …
