Patent ID: 7852046

Claim:
A battery-switching apparatus for switching between at least a first battery and a second battery, comprising: a first battery compartment having a first positive terminal and a first negative terminal; a second battery compartment having a second positive terminal and a second negative terminal; a comparator operatively electrically connected to the first negative terminal, electrically connected to the second negative terminal, configured to compare a first voltage at the first negative terminal with a second voltage at the second negative terminal, and configured to generate an output based on such comparison; and a single boost converter electrically connected to each of the first and second battery compartments, the boost converter operative to draw power from a one of the first and second battery compartments based on the output of the comparator; a first transistor operatively connected to the comparator; and a second transistor operatively connected to the comparator, wherein: the first and second transistors switch states according to the output of the comparator; the output of the comparator is electrically connected to a gate terminal of the first transistor and to a gate terminal of the second transistor; the first negative terminal is electrically connected to a drain terminal of the first transistor; and the second negative terminal is electrically connected to a drain terminal of the second transistor.