Patent ID: 6847191

Claim:
A power control device suitable for a portable electronic device using a battery as a power, the portable electronic device comprising a power consuming device, and the power control device comprising: a battery inner resistor detecting loading circuit electrically coupled to the battery for detecting a battery inner resistance of the battery; an A/D (analog to digital) converter electrically coupled to the battery for performing an analog to digital conversion of an analog voltage of the battery and outputting a digital voltage; and a CPU (central processing unit) electrically coupled to the battery inner resistor detecting loading circuit and the A/D converter, for controlling the turning ON/OFF operation of the battery inner resistor detecting loading circuit, in order to measure the battery voltage in the case when the battery inner resistor detecting loading circuit is turned off, the CPU obtains a first battery voltage via the A/D converter, and also to measure the battery voltage in the case when the battery inner resistor detecting loading circuit is turned on, the CPU obtains a second battery voltage via the A/D converter then a battery inner resistance of a battery inner resistor in the battery is calculated according to the first battery voltage and the second battery voltage; wherein, a voltage drop of the battery is calculated according to the first battery voltage, the battery inner resistance, and a consuming current of the power consuming device, when a voltage obtained from subtracting the voltage drop from the first battery voltage is lower than a predetermined cut-off voltage, a user of the portable electronic device is warned, and a power of the portable electronic device is turned off.