This reference design demonstrates a backup power supply design for smart meter applications. The TPS61022 boost converter has an extended operating range of 0.5V which maximizes the energy use of the supercapacitor energy. This results in a longer holdup time or a smaller supercapacitor. The BQ25173 provides constant current charging for the supercapacitor. The TPS2116 provides a seamless transition between the main power from the TPS62932 and the supercapacitor backup source.