All trademarks are the property of their respective owners.
DescriptionThe BQ77904 and BQ77905devices are low-power battery pack protectors that implement a suite of voltage, current, andtemperature protections without microcontroller (MCU) control. The device’s stackable interfaceprovides 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 ofconfigurations. Separate overtemperature and undertemperature thresholds for discharge (OTD andUTD) and charge (OTC and UTC) are provided for added flexibility.
The device achieves pack protection through the integrated independent CHG and DSGlow-side NMOS FET drivers, which may be disabled through two control pins. These control pins mayalso be used to achieve cell protection solutions for higher series (6 series and beyond) in asimple and economical manner. To do this, simply cascade a higher device CHG and DSG outputs to theimmediate lower device control pins. For a reduced component count, all protection faults useinternal delay timers.
Feature
- NORMAL mode: 6 μA (BQ77904 and BQ77905)
- Full suite of voltage, current, and temperatureprotections
- Scalable cell count from 3 series to 20 series ormore
- Voltage protection (accuracy ±10 mV)
- Overvoltage: 3 V to 4.575 V
- Undervoltage: 1.2V to 3 V
- Open cell and open-wire detection(OW)
- Current Protection
- Overcurrent discharge 1: –10 mV to –85 mV
- Overcurrent discharge 2: –20 mV to +170 mV
- Short circuitdischarge: –40 mV to +340 mV
- Accuracy ±20% for ≤ 20 mV, ±30% for > 20 mVacross full temperature
- Temperature protection
- Overtemperature charge:45°C or 50°C
- Overtemperature discharge: 65°C or 70°C
- Undertemperature charge: –5°C or 0°C
- Undertemperaturedischarge: –20°C or –10°C
- Additional
- Independent charge (CHG) and discharge (DSG) FETdrivers
- 36-V absolute maximum rating per cellinput
- Built-in-self-test functions for highreliability
- SHUTDOWN mode: 0.5-μA maximum
All trademarks are the property of their respective owners.
DescriptionThe BQ77904 and BQ77905devices are low-power battery pack protectors that implement a suite of voltage, current, andtemperature protections without microcontroller (MCU) control. The device’s stackable interfaceprovides 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 ofconfigurations. Separate overtemperature and undertemperature thresholds for discharge (OTD andUTD) and charge (OTC and UTC) are provided for added flexibility.
The device achieves pack protection through the integrated independent CHG and DSGlow-side NMOS FET drivers, which may be disabled through two control pins. These control pins mayalso be used to achieve cell protection solutions for higher series (6 series and beyond) in asimple and economical manner. To do this, simply cascade a higher device CHG and DSG outputs to theimmediate lower device control pins. For a reduced component count, all protection faults useinternal delay timers.
