Single inductor, multiple input, multiple output (SIMIMO) power mixer-charger-supply system

A hybrid energy source has become a necessary solution for micro-scale applications, like wireless sensors, because of small form factor and extended lifetime requirements. Conventional power mixer circuits use two or more inductors, which become prohibitively area intensive in micro-scale applications where area for discrete inductors is scarce and on-chip inductors are poor. Although single inductor multiple input or multiple output converters appear in recent literature, they cannot be applied to the hybrid energy source directly. A single inductor, multiple input, multiple output (SIMIMO) power mixer-charger-supply system is therefore proposed for a hybrid fuel cell-lithium ion source. The SIMIMO system adopts a novel nested hysteretic mode dual-loop control architecture, regulating both the fuel cell current and the output voltage within predetermined hysteres is windows. A SIMIMO with 67% average efficiency was designed and simulated, regulating the fuel cell current to 10mA and output voltage to 1.8V within ±20mV.