The TWL2203 incorporates a complete power-management system for a cellular telephone that uses lithium-ion cells. The device includes circuitry to control the gate voltage of two P-channel MOSFETs. The MOSFETs perform constant-voltage/constant-current charging (CVCC). The TWL2203 has seven low-drop linear voltage regulators (LDO) to regulate the battery power supply to the different sections of the phone, a battery voltage monitor, a ringer driver, an analog multiplexer, and three general-purpose operational amplifiers for signal conditioning.