Patent ID: 6690171
Filing Date: 2004-02-10
Classification: G01R

Abstract:
A battery capacity detection method, which utilizes a microprocessor with a pin to form a discharge circuit for a capacitor C in an RC circuit, the RC circuit and a battery forming a charge circuit, comprising the steps of:a) setting the pin in an output mode by the microprocessor so that the capacitor C releases its charge in the discharge circuit until it reaches the zero level; b) setting the pin from the output mode to the input mode by the microprocessor and starting to measure the charging time until the voltage of the capacitor C reaches a predetermined level; and c) obtaining the charge capacity of the battery according to the charging time by the microprocsssor. wherein the microprocessor contains a lookup table which records the times for batteries in different charge capacities to charge the capacitor C in the RC circuit from the zero level to the predetermined level.