Renesas' ISL81801 is a true bidirectional 4-switch synchronous buck-boost controller with peak and average current sensing and monitoring at both ends. With wide input and output voltage ranges, the controller is suitable for many industrial applications. The ISL81801 uses a proprietary buck-boost control algorithm with valley current modulation for boost mode and peak current modulation for buck mode control.

The ISL81801 has four independent control loops for input and output voltages and currents. Inherent peak current sensing at both ends and cycle-by-cycle current limit ensures high operational reliability by providing instant current limit in fast transient conditions at either end and in both directions. It also has two current monitoring pins at both input and output to facilitate constant current (CC) limit and other system management functions. CC operation down to low voltages avoids any runaway condition at overload or short-circuit conditions. In addition to multilayer overcurrent protection, it also provides full protection features such as OVP, UVP, OTP, average, and peak current limit on both input and output to ensure high reliability in both unidirectional and bidirectional operation. The unique DE/burst mode at light-load dramatically lowers standby power consumption with consistent output ripple over different load levels.

The IC is packaged in a space-conscious 32 LD 5 mm x 5 mm TQFN package or easy to assemble 4.4 mm x 9.7 mm 38 LD HTSSOP package. Both packages use an EPAD to improve thermal performance and noise immunity. Low pin count, fewer external components, and default internal values make the ISL81801 an ideal solution for time-to-market simple power supply designs.

Features

• Single inductor 4-switch buck-boost controller
• On-the-fly bidirectional operation with independent control of voltage and current on both ends
• Proprietary algorithm for smooth mode transition
• MOSFET drivers with adaptive shoot-through protection
• Wide input voltage range: 4.5 V to 80 V
• Wide output voltage range: 0.8 V to 80 V
• Supports startup into pre-biased rails
• Programmable frequency: 100 kHz to 600 kHz
• Supports parallel operation current-sharing with cascade phase interleaving
• External sync with clock out or frequency dithering
• External bias provides higher efficiency for 8 V to 36 V input
• Output and input current monitor
• Selectable PWM mode operation between PWM/DE/burst modes
• Accurate EN/UVLO and PGOOD indicator
• Low shutdown current: 2.7 µA
• Complete protection: OCP, SCP, OVP, OTP, and UVP
• Dual-level OCP with average current and pulse-by-pulse peak current limit; also provides short-circuit protection (SCP)
• Selectable OCP response with either hiccup or constant current mode
• Negative pulse-by-pulse peak current limit