Power Electronics

Controller

Linear Technology Corp.’s LTC4411 is a low-loss Power Path™ controller that controls an integrated P-channel MOSFET to create a near-ideal diode function for power switchover or load sharing. When conducting, the voltage drop across the MOSFET is as low as 28 mV, which is as much as ten times less than a comparable Schottky diode. This minimizes power dissipation and dropout voltage when Or-ing multiple power sources for extended battery life, low input voltage operation or minimal heat generation.

In addition, the LTC4411 improves system reliability by offering several protection features, including current limiting, thermal protection and reverse current detection for input supply protection. A logic-level input pin simplifies microcontroller interfacing, and an open-drain status pin indicates the conduction status of the LTC4411. This pin can be used to drive the gate of an external P-channel MOSFET for switching between two input supplies. The LTC4411 operates from 2.6-V to 5.5-V supplies and is housed in a SOT-23 package. Applications include devices that are powered from a battery and ac-dc input, load sharing and low-voltage backup power systems.

The LTC4411 contains a 140 mΩ P-channel MOSFET. During normal forward operation, the drop across the MOSFET is regulated to as low as 28 mV. Quiescent current is less than 40 µA for load currents up to 100 mA. If the output voltage exceeds the input voltage, the MOSFET is turned off and less than 1 µA of reverse current flows from OUT to IN. Maximum forward current is limited to a constant 2.6 A (typical) and internal thermal limiting circuits protect the part during fault conditions. During shutdown, the LTC4411 consumes less than 25 µA.

For more information, visit www.linear.com.

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