BQ77908A Texas instruments

BQ77908A

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BQ77908A

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Описание

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.Additional advanced safety features of the bq77908A include the ability to control split power-path MOSFETs, an open-cell sense-line detection mechanism, and the ability to detect an open or shorted external temperature sensor fault condition. Programmable Protection FunctionsWide range of programmable detection thresholds and delay times Configurable for multiple cell types and application requirements:Cell overvoltage Cell undervoltage Pack discharge overcurrentPack discharge short circuitPack charge short-circuit currentVariable gain (×1 or ×5) current-sense circuit Compatible with a wide range of current-sense resistors (1-mΩ to 5-mΩ typical) sized for application requirementsFixed Hardware Protection FunctionsPreset overtemperature protectionsOpen-cell detectionOpen and shorted thermistor detectionBrownout protection quickly shuts off FETs under low-battery conditions to minimize the risk of FET overheating

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
38-Pin TSSOP Package
Internal 50-mA Automatic Cell Balancing

Function	Protection
Number of series cells (min)	4, 5, 6, 7, 8
Number of series cells (max)	5, 6, 7, 8
Features	Cell balancing, FET drive, Overvoltage
Operating current (typ) (µA)	5
Rating	Catalog
Vin (max) (V)	50
Overvoltage protection	3.2, 4.2
Operating temperature range (°C)	-40 to 85
Battery overvoltage protection (min) (V)	4.15
Battery overvoltage protection (max) (V)	4.25