Li-Ion battery formation and electrical testing require accurate voltage and current control, usually to better than ±0.05% over the specified temperature range. This reference design proposes a solution for high-current (up to 50 A) battery tester applications supporting input (bus) voltages from 8 V–16 V and output load (battery) voltages from 0V–5V. The design utilizes an integrated multi-phase bidirectional controller, LM5170, combined with a high precisiondata converters and instrumentation amplifiers to achieve charge and discharge accuracies of 0.01% full scale. To maximize battery capacity and minimize battery formation time, the design uses highly-accurate constant current (CC) and constant voltage (CV) calibration loops with a simplified interface. All key design theories are described guiding users through the part selection process and optimization. Finally, schematic, board layout, hardware testing, and results are also presented.
- Battery test subsystem with calibration control achieving 0.01% full scale current control accuracy
- Supports up to 50-A applications with an input voltage (bus) from 8 V–16 V and output load (battery) from 0 V–4.5 V (5 V max)
- LM5170 bidirectional buck, boost controller
- Programmable high-precision reference supplied by DAC80004
- Voltage and current monitoring provided by the ADS131A04 24 bit delta-sigma
- User friendly control interface