This reference design demonstrates a cost-optimized onboard battery-charger solution for mid- or low-end vacuum robots: which has up to 1.5-A charging-current capability with a small layout area: providing ±3% charging-voltage accuracy and ±3% charging-current accuracy.The design enables a stable and smooth precharging to constant-current (CC) and constant-voltage (CV) charging profile and has been evaluated with a 4S2P li-ion battery pack.