Patent ID: 8541981

Claim:
A battery power-path management circuit, comprising: a first control circuit to establish a first power path between a battery input node and an output node when a voltage on said battery input node is larger than a voltage on a charger input node, and to establish a second power path between said charger input node and said output node when said voltage on said charger input node is larger than a voltage on said battery input node; said first control circuit being configured to control said second power path to provide power to said output node to enable charging and protecting a battery connected to said battery input node over a battery voltage range extending to zero volts; and a second control circuit for independently controlling respective backgates of first and second transistor switches according to voltages applied to said battery input node and said charger input node comprising circuitry for applying a voltage on said battery input node to said backgate of said first transistor switch if said voltage on said battery input node is greater than a voltage on said output node, and circuitry for applying a voltage on said charger input node to said backgate of said second transistor switch if said voltage on said charger input node is ,greater than a voltage on said output node.