Patent ID: 7456610
Filing Date: 2008-11-25
Classification: H02J

Abstract:
1. A battery charging apparatus for charging a plurality of batteries, the battery charging apparatus comprising: a plurality of charging units, each of the charging units comprising a series switch connected in series with a rechargeable battery and a parallel switch connected in parallel with the series connected rechargeable battery and the series switch such that each charging unit includes a single rechargeable battery; a charging power supply section for supplying charging current to the plurality of charging units which are connected in series; and a charging control section for switching the series switch and the parallel switch of the charging units ON and OFF and controlling charging of the corresponding rechargeable battery, wherein for each of the charging units, the charging control section is operable to turn the series switch ON and parallel switch OFF for a charging mode to charge the corresponding rechargeable battery, and to turn the series switch OFF and the parallel switch ON for a cut-off mode to bypass charging unit current flow through the parallel switch and not through the corresponding rechargeable battery, wherein for each of the charging units, the charging control section is operable to switch the series switch and the parallel switch ON and OFF to switch between the charging mode and cut-off mode to charge the corresponding rechargeable battery, and wherein for each of the charging units, the charging control section is operable to change the duty factor at multiple levels between 100% and 0% for switching the series switch and the parallel switch ON and OFF, and switch between the charging mode and the cut-off mode at a prescribed duty factor to control rechargeable battery charging current.