New Family Of Bidirectional Four-Switch Synchronous Buck-Boost Controllers

The controllers generate point-of-load (POL) and voltage rail conversions with peak efficiency up to 99 percent. The ISL81601 has a wide input range of 4.5V to 60V and produces a 0.8V to 60V output to support most industrial batteries: 12V, 24V, 36V and 48V. Also available is the ISL81401, a 4.5V to 40V input and 0.8V to 40V output version, and its unidirectional counterpart, the ISL81401A. The new controllers are well suited for DC power backup and battery-powered medical, industrial and telecommunication systems.

The ISL81601 and ISL81401’s bidirectional peak current sensing capability eliminates complex external circuitry required for charging and discharging a battery to supply power to the loads. Their proprietary algorithm provides smooth mode transitions between buck, boost and buck-boost, while reducing low frequency ripple at Vout, ensuring minimal disturbances during line or load transients. The algorithm also ensures predictable ripple voltage under all conditions. The addition of multilayer overcurrent protection and a precision control algorithm delivers constant current down to 0.1V at Vout for reliable operation. 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.

 “Our new bidirectional buck-boost controllers eliminate extra sensing circuitry and offer customers a robust feature-set that maintains battery health and superior power utilization,” said Philip Chesley, Vice President of Industrial Analog and Power Business Division, Renesas Electronics Corporation. “Leveraging Renesas’ proprietary modulation scheme and algorithms allows the highly integrated ISL81601, ISL81401 and ISL81401A to achieve the high reliability performance required for battery-powered equipment.”

The ISL81601 and ISL81401/A can be combined with a Renesas RL78 microcontroller (MCU), or other MCUs, to program the voltages, battery charge/discharge function, and on-the-fly bidirectional power flow. Designers can also use the PowerCompass tool to help them quickly identify other power supply parts that match their specific system requirements. Multiple power rails can be set up and designers can perform high-level system analysis and generate custom reference design files in minutes.