Controller designed to drive external N-Channel MOSFETs

Analog Devices LTC4421 Prioritized PowerPath Controller is intended to drive external N-Channel MOSFETs to connect one of two input supplies to a common output, based on user-defined priority and validity. The supply, by definition, is connected to V1 is the higher priority supply, although this can be modified dynamically. External resistive dividers fix the undervoltage and overvoltage thresholds bounding the valid voltage window.

Strong gate drivers switch the external N-channel MOSFETs swiftly. Fast switchover circuitry minimises output droop when switching channels while stopping reverse and cross conduction. A fast comparator identifies input short circuits and quickly turns off the N-channel MOSFETs to reduce disruption.

External sense resistors set the maximum inrush and current limit currents. Through current limiting, the device controls the N-channel MOSFET gate to regulate 25mV over the sense resistor. When the sense resistor voltage has been regulated to 25mV for a user-settable time, the channel is disconnected and a fault is set.

Typical applications include high-reliability systems, server-based back-up systems, industrial handheld instruments, and battery back-up systems.