Patent ID: 7541779
Filing Date: 2009-06-02
Classification: H02J

Abstract:
1. A portable electronic device comprising at least one electronic component being a heat source, which operates with a storage battery mounted therein as a power source: wherein, when the portable electronic device is connected to an external power source with the storage battery being mounted therein, the storage battery is charged by current from the external power source; a charging current detector circuit bridging a resistor circuit detects the current supplied by the external power source, a heat value of the resistor circuit being known; and when the storage battery is charged while said at least one electronic component is operating, circuitry internal to said electronic device is enabled to change the value of the charging current to charge the storage battery to a value less than that when the storage battery is being charged and said at least one electronic component is not operating, wherein the heat value of the resistor circuit is expressed as follows: where Rchg is a resistance value of the resistor circuit and Ichg is the charging current, wherein the resistor circuit comprises: a first resistor connected in series to a switch; and a second resistor connected in parallel to the first resistor and the switch.