The LTC4370 from Linear Technology is a two-supply current sharing controller which incorporates MOSFET ideal diodes. The diodes block reverse and shoot-through currents during start-up and fault conditions. Their forward voltage is adjusted to share the load currents between supplies. Unlike other sharing methods, neither a share bus nor trim pins on the supply are required.
The maximum MOSFET voltage drop can be set with a resistor. A fast gate turn-on reduces the load voltage droop during supply switchover. If the input supply fails or is shorted, a fast turn-off minimizes reverse current transients.
The controller operates with supplies from 2.9 V to 18 V. For lower rail voltages, an external supply is needed at the VCC pin. Enable inputs can be used to turn off the MOSFET and put the controller in a low current state. Status outputs indicate whether the MOSFETs are on or off. The load sharing function can be disabled to turn the LTC4370 into a dual ideal diode controller.