The ISL78220 6-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.

The ISL78220 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.

Input current is sensed continuously by measuring the voltage

across a dedicated current sense resistor or by inductor DCR.

This current sensing provides precision channel-current

balancing, and per-phase overcurrent protection. A separate

totalizing current limit function provides overcurrent protection

for all the phases combined. This two-stage current protection

provides maximum performance and circuit reliability.

The ISL78220 can also provide for input voltage tracking via

the VREF2 pin. The comparison reference voltage will be the

lower of the VREF2 pin or the internal 2V reference. By using a

resistor network between VIN and VREF2 pin, the output

voltage can track input voltage to limit the output power during

automotive cranking conditions.

The ISL78220 can output a clock signal for expanding

operation to 12 phases, which offers high system flexibility.

The threshold-sensitive enable input is available to accurately

coordinate the start-up of the ISL78220 with any other voltage rail.

Features

• Peak current mode PWM Control with adjustable slope

compensation

• Precision resistor/DCR current sensing

• 2-, 3-, 4- or 6-phase operation

• Adjustable phase dropping/diode emulation/pulse skipping

for high efficiency at light load

• 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

• 2V ±1.0 internal reference

• Pb-free, 44 Ld 10x10 EP-TQFP package (RoHS compliant)

• -40°C to +125°C operating temperature range

• AEC Q100 qualified

Applications

• Automotive power supplies

- Start/stop DC/DC converter

- Electronic power steering systems (EPAS)

- Fuel pumps

- Injection system

• Audio trunk amplifier power supplies

• Telecom and industrial power supplies