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.