Patent ID: 7821230
Filing Date: 2010-10-26
Classification: H02J

Abstract:
1. A charging system for charging a rechargeable battery, comprising: N battery cells coupled in series forming a series string, wherein said series string comprises: a first set of charging sources coupled to said series string, wherein each charging source in said first set of charging sources comprises an input terminal and an output terminal, wherein an input terminal of each of the charging sources of the first set of charging sources is directly connected to a power source, an output terminal of a first charging source of said first set of charging sources is coupled to the load, and an output terminal of each of the other charging sources of the first set of charging sources is coupled to a respective cell junction, wherein each of the charging sources of the first set of charging sources provides a charging current in a first state of operation and does not provide a charging current in a second state of operation and wherein an N−1 charging source of the first set of charging sources provides a charging current for an N−1 battery cell and for the N a second set of charging sources coupled to said series string comprising exactly N−1 charging sources, wherein each charging source in said second set of charging sources comprises an input terminal and an output terminal, wherein an input terminal of each charging source in said second set of charging sources is coupled to a respective cell junction, and an output terminal of each charging source in said second set of charging sources is coupled to the ground, wherein each of the charging sources of the second set of charging sources diverts a charging current to the ground provided by a charging source of the first set of charging sources when operating in a first state and does not divert a charging current to ground when operating in a second state and wherein the N−1 charging source of the second set of charging sources diverts to the ground the charging current for the N−1 battery cell and the charging current for the N a controller for selectively operating each charging source of the first set of charging sources and each charging source of the second set of charging sources in the first state or the second state to provide a charging current to each battery cell having a voltage less than a predetermined voltage.