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Renesas Electronics Corporation has announced an innovative new family of bi-directional four-switch synchronous buck-boost controllers.

The ISL81601 and ISL81401 are the industry’s only true bi-directional controllers that sense peak current at both ends and provide cycle-by-cycle current limiting in both directions while in buck or boost mode. They generate Point-of-Load (PoL) power supplies at a peak efficiency of up to 99%.

The ISL81601 has a wide input-voltage range of 4.5V to 60V and produces a 0.8V to 60V output. This is compatible with most industrial batteries, which typically operate at 12V, 24V, 36V or 48V. Also available is the ISL81401, which has a 4.5V to 40V input range and 0.8V to 40V output range, and a unidirectional counterpart, the ISL81401A.

The ISL81601 and ISL81401’s bi-directional peak current-sensing capability eliminates the complex external circuitry required for charging and discharging a battery that supplies power to loads. Their proprietary algorithm provides smooth transitions between buck, boost and buck-boost modes, while reducing low frequency ripple at the output. This produces minimal disturbance during line or load transients. The algorithm also maintains a predictable ripple voltage under all conditions.

Designers can easily expand system power by paralleling an unlimited number of controllers. The ISL81601 and ISL81401 operate two switches at a time to minimize power loss and achieve higher efficiency.


ISL81x01: Wide 4.5V to 60V input-voltage range

  • Programmable frequency range: 100kHz to 600kHz
  • MOSFET drivers with adaptive shoot-through protection
  • Light-load efficiency mode
  • 2.7μA shut-down current
  • Frequency dithering for lower EMI in ISL81601 and ISL81401
  • Over-voltage, under-voltage, over-current, over-temperature and short-circuit protection functions
  • DC power back-up
  • Medical equipment
  • Industrial systems
  • Telecoms equipment


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