Description

The LTC4413 contains two monolithic ideal diodes, each capable of supplying up to 2.6A from input voltages between 2.5V and 5.5V. Each ideal diode uses a 100mΩ  P-channel MOSFET that independently connects INA to OUTA and INB to OUTB. During normal forward operation the voltage drop across each of these diodes is regulated to as low as 28mV. Quiescent current is less than 40µA for diode currents up to 1A. If either of the output voltages exceeds its respective input voltages, that MOSFET is turned off and less than 1µA of reverse current will flow from OUT to IN. Maximum forward current in each MOSFET is limited to a constant 2.6A and internal thermal limiting circuits protect the part during fault conditions.

Two active-high control pins independently turn off the two ideal diodes contained within the LTC4413, controlling the operation mode as described by Table 1. When the selected channel is reverse biased, or the LTC4413 is put into low power standby, a status signal indicates this condition with a low voltage. A 9µA open-drain STAT pin is used to indicate conduction status.When terminated to a positive supply through a 470k resistor, the STAT pin can be used to indicate that the selected diode is conducting with a high voltage. This signal can also be used to drive an auxiliary P-channel MOSFET power switch to control a third alternate power source when the LTC4413 is not conducting forward current.

The LTC4413 is housed in a 10-lead DFN package.

Features

2-Channel Ideal Diode ORing or Load Sharing

Low Loss Replacement for ORing Diodes

Low Forward On-Resistance (100mΩ Max at 3.6V)

Low Reverse Leakage Current (1µA Max)

Small Regulated Forward Voltage (28mV Typ)

2.5V to 5.5V Operating Range

2.6A Maximum Forward Current

Internal Current Limit and Thermal Protection

Slow Turn-On/Off to Protect Against Inductive  Source Impedance-Induced Voltage Spiking

Ultralow Quiescent Current Consumption, Low  Power Alternative to the LTC4413-1

Status Output to Indicate if Selected Channel is Conducting

Programmable Channel On/Off

Low Profile (0.75mm) 10-Lead 3mm × 3mm DFN Package

Applications

Battery and Wall Adapter Diode ORing in Handheld Products

Backup Battery Diode ORing

Power Switching

USB Peripherals

Uninterruptable Supplies

 

Applications information

Introduction

The LTC4413 is intended for power control applications that include low loss diode ORing, fully automatic switchover from a primary to an auxiliary source of power, microcontroller controlled switchover from a primary to an auxiliary source of power, load sharing between two or more batteries, charging of multiple batteries from a single charger and high side power switching. The LTC4413 is optimized for low quiescent power consumption at the expense of transient response. For more demanding slew rate or load transient applications, the pin compatible LTC4413-1 is recommended.

Dual Battery Load Sharing with Automatic Switchover to a Wall Adapter

When the wall adapter is not present, whichever battery that has the higher voltage provides the load current until it has discharged to the voltage of the other battery. The load is then shared between the two batteries according to the capacity of each battery. The higher capacity battery provides proportionally higher current to the load. When a wall adapter input is applied, the voltage divider formed by R1 and R2 disables the LTC4413, causing the STAT pin voltage to fall, turning on MP1. At this point the load is powered by the wall adapter and both batteries may be removed without interrupting the load voltage. When the wall adapter is removed, the output voltage droops until the voltage divider turns on the LTC4413, at which point the batteries revert to providing load power. The status signal can also be used to provide information as to whether the wall adapter (or BATB) is supplying the load current.