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This IC is designed for multi-cell lithium-ion and lithium-polymer battery packs, offering a comprehensive solution for battery protection, cell balancing, and fuel gauging. Its primary function is to serve as the "brain" of a smart battery pack, ensuring safe and efficient operation while providing detailed data to the host device.
A common activity is attempting to revive or repurpose laptop batteries. When the internal lithium-ion cells degrade and no longer hold a charge, users often wish to replace them. However, simply swapping the cells is not enough because the BQ40370 stores a record of the old, worn-out cells' capacity in its internal memory. To fix this, the chip must be . Tools like the NLBA (a specialized battery adapter) and the EV2300 or EV2400 (TI's standard communication interfaces) are used to interface with the chip. These tools allow advanced users to unseal the chip, read and edit its data, and then seal it again. bq40370
Tracks remaining capacity, state of charge (SOC), and full charge capacity (FCC). Protection:
Due to its widespread use in consumer electronics, the BQ40370 is a frequent subject in battery repair forums. When a battery pack stops charging or reports incorrect capacity, it is often due to the IC entering a "sealed" or "protected" mode due to a detected fault (e.g., cell imbalance, overvoltage). Challenges in Repair Is it a: This IC is designed for
: 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
To ensure accuracy, the gauge must be "tuned" to the specific battery cells used in the product. This process, often called creating a "Golden Image," involves: When the internal lithium-ion cells degrade and no
It utilizes a 32-pin QFN package (RSMR) , maximizing PCB space efficiency inside thin-and-light laptop enclosures.
The BQ40370 often enters a "locked" state or triggers a Permanent Failure Flag (PFF) if it detects a cell imbalance or if the battery cells are disconnected during a repair.
Once triggered, the chip sets a in its non-volatile memory (DataFlash). Even if you solder brand-new cells into the battery pack, the BQ40370 will refuse to charge or discharge, leaving the output voltage at 0V. Reprogramming, Unsealing, and Repairing BQ40370 Batteries