BQ77915 Stackable Ultra-Low-Power Primary ProtectorTexas Instruments' 3-series to 20-series stackable protector features autonomous cell balancing and HIBERNATE modeTexas Instruments' BQ77915 is a low-power battery pack protector that features voltage, current, and temperature protections and a smart cell-balancing algorithm without microcontroller (MCU) control. The device's stackable interface provides simple scaling to support battery-cell applications from 3-series to 20-series or more. Protection thresholds and delays are factory-programmed and available in a variety of configurations. Separate thresholds for overtemperature discharge (OTD), undertemperature discharge (UTD), overtemperature charge (OTC), and undertemperature charge (UTC) are provided for added flexibility.

The device achieves pack protection via the integrated independent charge (CHG) and discharge (DSG) low-side NMOS FET drivers which can be disabled through two control pins. These control pins offer cell protection solutions for higher series (6-series and beyond) in a simple and economical manner. To do this, cascade a higher device CHG and DSG outputs to the immediate lower device control pins. The discharge overcurrent protection delays provide flexibility and can be programmed using a resistor connected from the OCDP pin to VSS.

The BQ77915 protector achieves a smart, passive cell-balancing algorithm via integrated FETs for cell-balancing currents up to 50 mA. For higher cell-balancing current requirements, external FETs can be connected. The HIBERNATE mode intended for shipping and storage enables ultra-low-power operation. The BQ77915 protector is designed for battery packs where no host monitoring is required.FeaturesUltra-low quiescent current: 8 μA typ. (NORMAL mode), and 2 μA (HIBERNATE mode)Voltage, current, and temperature protectionsSmart passive cell-balancing removes cell-to-cell imbalanceScalable cell count from 3-series to 20-series or moreVoltage protection (accuracy ±10 mV for overvoltage (OV) and ±18 mV for undervoltage (UV)):OV: 3 V to 4.575 VUV: 1.2 V to 3 VOpen-cell and open-wire detection (OW)SHUTDOWN mode: 0.5 μAHigh 36 V absolute max. rating per cell inputIndependent CHG and DSG FET driversCurrent protection:OCD 1: -10 mV to -85 mVOCD 2: -20 mV to -170 mVShort-circuit discharge: -40 mV to -340 mVTemperature protection:OTC: +45°C or +50°COTD: +65°C or +70°CSmart cell-balancing algorithm with integrated FETs (up to 50 mA balancing current), supports external FETs for higher cell-balancing currentUltra-low-power HIBERNATE modeResistor programmable overcurrent (OCD1/2) delayApplicationsPower tools and garden toolsRobotic cleaners, vacuum cleaners, and hoverboardseBikes10.8 V to 72 V packsBQ77915 Ultra-Low-Power Protective PackImageManufacturer Part NumberDescriptionAvailable QuantityView DetailsBQ7791504PWPOWER MANAGEMENT IC240 - ImmediateView DetailsEvaluation BoardImageManufacturer Part NumberDescriptionTypeFunctionUtilized IC / PartAvailable QuantityView DetailsBQ77915EVM-014DEVELOPMENT POWER MANAGEMENTPower ManagementBattery ProtectionBQ779151 - Immediate

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