[cracked] | Bq40370

Unlike the "Z" family of TI chips (like the BQ40Z50 ), which use pure Impedance Tracking, the BQ40370 relies on CEDV. This means it does not require long relaxation periods to calculate state-of-charge (SoC). Common Applications and Repairs

| Issue | Likely Cause | Potential Solution | | :--- | :--- | :--- | | Battery shows 0V output, but cells have voltage | Controller has locked the output MOSFET due to a fault condition | Attempt to unseal and reset the chip using NLBA or similar tools | | Sudden SOC drops (e.g., 60% to 6%) | Discharge curve not aligned with factory profile; cells replaced without updating EMF/EDV parameters | Full chip reprogramming with correct EMF/EDV values for the new cells | | Chip doesn't respond or appears bricked | Incorrect editing of EEPROM dump; wrong byte order used for editing values | Restore original dump if available; otherwise, chip may be permanently damaged | | Cannot unseal chip | Network connectivity issues during remote unseal; wrong unseal procedure | Check internet connection; try different network; use NLBA software's built-in unseal functions | | Battery charges to 100% but dies quickly | FCC value incorrect; cells have lower capacity than what chip expects | Recalibrate battery with correct FCC value matching actual cell capacity | | Max Error stays at 8% | Discharge current for calibration too high; relaxation periods incorrect | Use average laptop consumption current (not 3000mA); follow correct 120min relaxation periods | | Cell imbalance persists | Bad cell balance from factory; chip unable to balance cells sufficiently | Manually charge individual cells to same voltage before attempting reset |

The BQ40370 is a highly integrated and accurate battery management IC suitable for a wide range of portable and wearable applications. Its low power consumption, high accuracy, and configurability make it an ideal choice for designers looking to optimize battery performance and extend battery life. bq40370

Wide operating range to accommodate 2S to 4S (7.2V to 14.8V) configurations.

: To keep the laptop's host operating system accurately updated, the BQ40370 features high-resolution analog-to-digital converters (ADCs). It continuously multiplexes signals to monitor individual cell voltages, battery pack temperature (via negative temperature coefficient thermistors), and real-time charging/discharging current passing through an external low-side current sense resistor. Key Technical Specifications (Architectural Matrix) Unlike the "Z" family of TI chips (like

The BQ40370 functions as a and protection IC, managing the charge and discharge cycles of multi-cell lithium-ion packs.

: The "Advanced" element integrates elements of Texas Instruments' proprietary Impedance Tracking technology. This allows the chip to look at battery degradation over time, tracking internal resistance shifts without needing the rigid, extended chemical relaxation periods required by pure IT gauges. Hardware Protection Features Its low power consumption

is a custom Texas Instruments battery management chip frequently found in Dell laptop batteries

Overvoltage and undervoltage conditions at the individual cell level. Overcurrent during charge or discharge cycles. Short-circuit scenarios. Thermal boundaries via connected NTC thermistors. The Permanent Failure (PF) Lock Mechanism