The MAX1894/MAX1924VEEE are lithium-ion/lithium-polymer (Li+) battery-pack protector ICs for 3- or 4-series Li+ battery packs. The MAX1894/MAX1924VEEE enhance the useful operating life of Li+ batteries by monitoring individual cell voltages and preventing over/undervoltage conditions. The MAX1894/MAX1924VEEE also protect the battery pack against charge current, discharge current, and pack-short fault conditions. In case of a fault condition, on-board drivers control external P-channel MOSFETs, which disconnect the cells from the pack external terminals. The external protection MOSFETs are connected in a common-source configuration that does not require external pullup resistors. The MAX1894/MAX1924VEEE use only one current-sense resistor to achieve the protection features. All protection thresholds and delays do not require any external components and are trimmed at the factory.If any cell voltage drops below the undervoltage threshold, the MAX1894/MAX1924VEEE disconnect the pack from the load and power down to prevent deep discharge of the pack. The MAX1894/MAX1924VEEE offer a trickle-charge feature, which provides a low-current path to safely charge a deeply discharged pack. The MAX1894/ MAX1924VEEE also have two logic-level inputs, which can be used by a microcontroller to disable the protection MOSFETs and to put the device in shutdown. The MAX1894/MAX1924VEEE have low quiescent current (30μA typ) and ultra-low shutdown current (0.8μA typ) to prevent deep-cell discharge.The MAX1894X is designed for 4-series battery packs, without hysteresis on the protection thresholds. The MAX1924V and MAX1924X include hysteresis for the 3- and 4-series packs, respectively.
Feature
- Protect Against Cell Overvoltage Factory Programmable Limits from 4V to 4.4V Accurate to ±0.5%
- Protect Against Cell Undervoltage Factory Programmable Limits from 2V to 3.2V Accurate to ±2.0%
- Protect Against Charge, Discharge, and Pack- Short Current Faults
- Automatically Trickle Charges Deeply Discharged Cells
- Fully Integrated MOSFET Drivers Do Not Require Pullup Resistors
- 0.8μA (typ) Shutdown Supply Current Prevents Deep Discharge of Cells
- 30μA (typ) Operating Supply Current
- 28V (max) Input Voltage
- Available in Small 16-Pin QSOP Package
Applications
- 3- or 4-Series Li+ Battery Packs
