Patent ID: 8384356

Claim:
In a circuit having a self contained DC/DC power source comprising: a first power source of a rechargeable battery; a second power source for providing a potential that is less than 0.4 volts; a boost voltage converter coupled to the second power source to boost the voltage of the second power source to a voltage that is at least equal to the voltage of the first power source; said boost voltage converter having an inductor and a switching device connected in series with said second power source; a diode in series with a capacitor coupled across the switching device; a voltage divider coupled across the capacitor; a pulse width modulator coupled across the voltage divider to receive an input from the voltage divider to provide an input to a control terminal of the switching device; a first push circuit having a one-pulse control circuit, coupled to the first power source, the second power source and the control terminal of the switching device in the boost voltage converter wherein said one-pulse control circuit generates a single pulse to turn on the switching device for the first time and the pulse width modulator circuit controls the switching device during subsequent normal operations; a power path management circuit connected to the output voltage of the boost voltage converter in series, and coupled to the control terminals of multiple switches; and a battery charger circuit coupled to the output voltage of the boost voltage converter through a switch, of which the control terminal is coupled to the power path management circuit; wherein said battery charger circuit has an output coupled to the first power source to provide a charging current to the first power source.