Based on CSMC 0.13um 3.3V/1.2V Logic process, current design of the Battery Charger IP is a complete constant current/constant voltage linear charger for single cell lithium-ion and lithium-polymer ...

On the other hand, some P-channel devices work at lower voltages (approx 0.2V lower), and that suits it well for 1.2V battery applications. The rest is human–the mind visualizes well against ground ...