Datasheet

ISL9211B
Charging System Safety Circuit

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Typical Diagram

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Key Features

24V Max Input Voltage
Supports Up To 2.0A Input Current
Fully Integrated Protection Circuit for Three Protected Variables
High Accuracy Protection Thresholds
User Programmable Overcurrent Protection Threshold
Responds to Input Overvoltage in Less Than 1µs
High Immunity of False Triggering Under Transients
Fault Indication for Various Fault Occurrence
Easy to Use
Pb-Free (RoHS Compliant)

Description

The ISL9211B is an integrated circuit (IC) optimized to provide a redundant safety protection to a Li-ion battery charging system. The IC monitors input voltage, battery voltage, and charge current. When any of these parameters exceeds its limit, the IC turns off an internal N-channel MOSFET to remove power from the charging system to the battery. The IC also monitors its own internal temperature and turns off the N-channel MOSFET when the temperature exceeds +150°C. Together with the battery charger IC and the protection module in a battery pack, the charging system using the ISL9211B has triple-level protection and is two-fault tolerant.

The IC is designed to turn on the internal NFET slowly, to avoid in-rush current at
power-up. It turns off the NFET quickly when the input is overvoltage, to remove power before damage occurs. The ISL9211B has a logic flag output to indicate a fault condition. The enable input allows the system to cut off the input power, if needed.