BQ77908A

Product Folder Sample & Buy Technical Documents Tools & Software Support & Community bq77908A SLUSAV5A – FEBRUARY 2012 – REVISED OCTOBER 2014 bq77908A Multi-Cell Lithium-Ion/Polymer Precision Protector Not Recommended for New Designs 1 Features 4-, 5-, 6-, 7-, or 8-Series Cell Protection Individual Cell-Voltage Monitoring Low-Side NMOS FET Drive for Charge and Discharge Control Compatible With 1-mΩ Current-Sense Resistor Supply-Voltage Range From 5.6 V to 40 V Integrated 3.3-V Micro-Power LDO Regulator Low Supply Current – Normal Mode: 50 µA, Typical – Shutdown Mode, LDO OFF: 5 µA, Typical 1 38-Pin TSSOP Package Internal 50-mA Automatic Cell Balancing 2 Applications Cordless Power Tools Cordless Lawn Equipment Electric Bikes UPS Light Electric Vehicles (LEV) 3 Description The bq77908A is a battery protection and cell balancing device intended for Li-Ion and Li-Polymer battery packs. The bq77908A monitors 4- to 8-series individual cell voltages and provides fast-acting outputs that may be used to drive N-channel MOSFETs to interrupt the power path. Activation delays and recovery methods for safety conditions are fully programmable in non-volatile memory. Automatic cell balancing is provided using internal 50-mA cell circuits. A robust balancing algorithm ensures optimum performance by maintaining all cell voltages in balance. Balancing may be configured to operate at all times, only during charge, or can be disabled completely. PART NUMBER ...