Patent ID: 8900731

Claim:
A charger system for a portable host device comprising: a charger circuit operating to communicate a charge status using a charger side communication line selected from a charging status and a charge completed status; a battery coupled between the portable host device and the charger circuit, the battery comprising a switch circuit connected to the charger side communication line and operating to switch communication to the portable host device in response to the charge status communicated from the charger circuit; the portable host device; wherein the charger circuit communicates the charge status by a DC voltage level charge status using the charger side communication line; wherein the switch circuit comprises: an output coupled to the portable host device which selectively switches a host side communication line to ground, and an input coupled to the charger circuit which causes the output to switch upon application of a DC voltage level of sufficient duration to exceed a time constant of an input circuit; wherein the battery further comprises: a first memory device for communication with the portable host device via the host side communication line, the first memory device is connected with the portable host device independent of the charge status but is readable only by the portable host device when the charge status is the charge completed status; and a second memory device for communication with the charger circuit via the charger side communication line, the second memory device is connected with the charger circuit independent of the charge status through charger side communication line.