A Control Circuit for a Microsensor Hybrid Power Supply

This paper presents a simple low-power control circuit intended to manage the power within a remote autonomous microsystem hybrid power supply. A hybrid power supply has only recently been discussed in the literature as a microsystem power source solution. The power management circuitry, which is a key component within a hybrid power supply, has not been adequately explored. Although a variety of components could have been implemented, the control circuit in this paper was designed for a hybrid power supply that utilizes a Ni/Zn microbattery and silicon solar cell. The circuit also employs a shunt architecture powered only by the solar cell to minimize the overall energy consumption of the hybrid power supply. The control circuit consumes a maximum of 7 /spl mu/A and appropriately manages power even when the hybrid power supply is connected to a microsystem and is experiencing environmental variations. Details of the control circuit are discussed and simulations combined with experimental results demonstrate its performance.