Regulated 3.3V low ripple charge pump with low battery indicator

The TPS6020x step-up, regulated charge pumps generate a 3.3-V ±4% output voltage from a 1.8-V to 3.6-V input voltage. The devices are typically powered by two Alkaline, NiCd, or NiMH battery cells and operate down to a minimum supply voltage of 1.6 V. Continuous output current is a minimum of 100 mA from a 2-V input. Only four external capacitors are needed to build a complete low-ripple dc/dc converter. The push-pull operating mode of two single-ended charge pumps assures the low output voltage ripple, as current is continuously transferred to the output.