Patent ID: 8743574

Claim:
An energy harvesting system for a micro-scale electronic device, the system comprising: an energy transducer configured to produce electrical energy, the energy transducer having an output configured to supply a first voltage; an energy storage device configured to store electrical energy; and a power converter configured to transfer electrical energy from the transducer to the energy storage device, the power converter including a charge pump coupled between the energy transducer and the energy storage device and a control unit configured to control operation of the charge pump, the charge pump including a first stage, a second stage, and a third stage, each of the first and second stages having an output and at least one input coupled to the output of the transducer so that the transducer supplies the first voltage to the at least one input of the first and second stages, the first and second stages of the charge pump providing second and third voltages at their outputs, respectively, the second and third voltages being greater than the first voltage, the outputs of the first and second stages being coupled to first and second inputs of the third stage of the charge pump and an output of the third stage supplying a fourth voltage to the energy storage device, the fourth voltage being greater than the second and third voltages, wherein the first stage of the charge pump includes first and second inputs coupled to the output of the transducer, the first input of the first stage also being coupled to a first plate of a first capacitor through a first switch, and the second input of the first stage being coupled to a second, opposite plate of the first capacitor through a second switch, the first plate of the first capacitor also being coupled to a third switch which is also coupled to the output of the first stage, the second stage of the charge pump includes first and second inputs coupled to the output of the transducer, the first input of the second stage also being coupled to a first plate of a second capacitor through a fourth switch, and the second input of the second stage being coupled to a second, opposite plate of the second capacitor through a fifth switch, the first plate of the second capacitor also being coupled to a sixth switch which is also coupled to the output of the second stage, and the first input of the third stage is coupled to a first plate of a third capacitor, and the second input of the third stage is coupled to a second, opposite plate of the third capacitor, the first plate of the third capacitor also being coupled to a seventh switch which is also coupled to the output of the third stage, the control unit providing at least one clocking signal to selectively open and close the first, second third, fourth, fifth, and sixth switches to control operation of the charge pump.