CONTROLLING METHOD FOR USING AN ADDITIONAL FUNCTION IN A LOW VOLTAGE PORTABLE PHONE, ESPECIALLY IN REFERENCE TO CONTINUOUSLY USING THE ADDITIONAL FUNCTION EXCEPT A CALL FUNCTION WITH A MINIMUM OPERATIONAL VOLTAGE

摘要

PURPOSE: A controlling method for using an additional function in a low voltage portable phone is provided not to cut off power for a minimum operational voltage, which does not damage a circuit even though a battery voltage drops at less than a predetermined threshold voltage, thereby continuously using additional functions with little power consumption. CONSTITUTION: A system frequently checks a battery voltage while normally operating all functions including a call function(S302). The system compares the checked voltage with the first threshold voltage(S304). If the battery voltage is less than the first threshold voltage, the system converts a portable phone into an additional function mode(S306). The system checks the battery voltage(S308), and compares the battery voltage with the second threshold voltage(S310). If the battery voltage is less than the second threshold voltage, the system cuts off power(S312).