The DV2057/C/T/W are complete development and evaluation environments for bq2057 series advanced Li-Ion linear charge management ICs. The DV2057 family supports both single- and dual-cell Li-Ion packs with coke or graphite anodes:
- DV2057 - regulation voltage = 4.1V
- DV2057C - regulation voltage = 4.2V
- DV2057T - regulation voltage = 8.2V
- DV2057W - regulation voltage = 8.4V
Full charge is preceded by charge qualification based on battery temperature and voltage. The DV2057T suspends charge if the battery temperature is outside the VTS1 to VTS2 thresholds and waits until the battery temperature is within the allowed voltage. If the battery voltage is below the low-voltage threshold, VMIN, the DV2057T uses trickle charge to condition the battery. The conditioning charge rate, ICOND, is set at approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass element during the initial stage of charge.
Once the battery voltage reaches the internal threshold, VMIN, full charge begins. The DV2057T completes the charge cycle in two phases. While the pack is below the regulation voltage, a constant-current phase replenishes approximately 70% of battery capacity. An accurate voltage-regulation phase completes the charge. The DV2057T terminates charge when the current tapers off to the VTERM threshold.
These boards feature the proprietary AutoCompTM technique to compensate safely for the internal impedance of the battery. The AutoCompTM resistors, RCOMP1, and RCOMP2, must be set according to the characteristics of the battery.
Before using these development boards, please review the bq2057 datasheet.