Patent ID: 7626360

Claim:
A battery protection circuit for charging a battery from a charger and discharging said battery to a load, said circuit comprising: a pair of battery terminals for connecting said battery; an input-output terminal for connecting at least one of said load and said charger; a pass transistor having a first drain/source connection coupled to a given one of said battery terminals and a second drain/source connection coupled to said input-output terminal; a charge-pump circuit having an output coupled to a gate of said pass transistor, wherein said charge pump circuit charges said gate of said pass transistor to a gate voltage such that a magnitude of a voltage between said gate of said pass transistor and said first drain/source connection is greater than a magnitude of a voltage across said battery terminals; and a second charge pump having an output coupled to a body of said pass transistor, for charging said body of said pass transistor to a voltage having a polarity opposite a polarity of said gate voltage with respect to both of said drain/source terminals of said pass transistor.