| 摘要 |
PURPOSE: An apparatus for measuring voltage of a portable phone battery and a method thereof are provided to acquire a reference voltage using a constant-voltage supply device. CONSTITUTION: A selector(240) outputs a power of a battery(230) or a power of a constant-voltage supply device according to a control signal. The third resistor(R3) divides the voltage from the selector(240). The fourth resistor(R4) is connected to the third resistor(R3) in series. A converter(210) converts voltage of the fourth resistor(R4) to a digital value of 8 bits. A CPU(200) of a portable phone receives an output signal of the converter(210), calculates voltage of the battery(230), and outputs the control signal to the selector(240). A memory(250) is connected to the CPU(200) of a portable phone and stores a voltage value of the constant-voltage supply device(220) as a reference voltage.
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