Battery level indicator for a telephone set

Abstract

A battery level indicator is provided in a mobile phone, which is equipped with a communication mode and a standby mode where the current drawn from the battery is different, to display the level of the battery that powers the mobile phone. The battery level indicator includes a battery voltage measuring unit, a correction unit, a level determining unit and a liquid crystal display. The battery voltage measuring unit measures the voltage of the battery at regular intervals, such as every 0.5 seconds. The correcting unit corrects voltage measurements obtained during communication mode by adding correction values specified using a correction value table. The level determining unit calculates an average for voltage measurements, which have been corrected as necessary, produced during a preceding period such as fifteen seconds. This average may be calculated every second, for example. The level determining unit compares the average with a level table that associates voltages during standby mode with notification levels and determines the appropriate notification level. The liquid crystal display displays a symbol that represents the determined notification level.