US Patent 8432132 Battery pack manager

A manager that lessens a difference in state of charge of a battery pack. The battery pack is constituted of a plurality of blocks. A slave unit is provided for each of the blocks, to thus detect a terminal voltage of the block and supply the detected terminal voltage to a master unit. A difference arises in state of charge among the blocks for reasons of a difference in current consumption of the respective slave units. The master unit makes up an operation clock signal for each of the slave units from a high frequency signal and a low frequency signal. A difference in state of charge among the blocks is lessened by controlling an appearance ratio of the high frequency signal to the low frequency signal for each of the slave units.