| 摘要 |
PURPOSE: Provided are an apparatus and a method for detecting battery voltage of a cellular phone, which can detect accurately the battery voltage of the cellular phone regardless of the error of distribution resistance. CONSTITUTION: The apparatus comprises: a battery voltage inputting part(21) dividing the battery voltage in the fixed ratio; an A/D converter(22) converting the divided battery voltage into digital signals by using the battery voltage or external reference voltage as a reference voltage; a central processing unit(23) calculating the division ratio of the battery voltage by reading the data outputted from the A/D converter(22) when the booting of the cellular phone starts and judging present battery voltage from the data and the division ratio; a multiplexer(24) selecting the battery voltage or the external reference voltage by the control of the central processing unit(23) and supplying as the reference voltage of the A/D converter(22), wherein the multiplexer(24) selects the battery voltage when booting the cellular phone and after then selects the external reference voltage.
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