Battery alarm system

• US 5,239,286 A
• Filed: 08/30/1991
• Issued: 08/24/1993
• Est. Priority Date: 08/31/1990
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Komatsuda, Seiji
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Lefkowitz, Edward
• Application Number:
  US07/752,880
• Time in Patent Office: 725 Days
• Field of Search: 340/636, 324/433, 324/435, 324/426, 320/48
• US Class Current: 340/636.15
• CPC Class Codes: H04W 52/0261 managing power supply demand, e.g. depending on battery level
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A battery alarm system for generating an alarm on recognition of the reduction of an output voltage of a battery, wherein an analog output voltage value of a battery is converted to a digital value. The digitalized values are inputted into a controller for a plurality of times at predetermined intervals to obtain the average value, and when the average value is smaller than the predetermined threshold stored in the memory, an alarm is generated. By obtaining an average value of voltage values inputted for a plurality of times, an alarm can be produced stably with little influence of fluctuations of the output voltage of the battery.

Claims

1. A battery alarm system for producing an alarm from an alarm generating means upon recognizing a reduction in an output voltage of a battery, the system comprising:

an analog/digital converting means for converting analog values of the output voltage of said battery to digital values,

a storing means for storing a threshold corresponding to an output voltage of said battery which is determined to be sufficiently low to generate an alarm and indicate an alarm state of the battery, and

a control means connected to said converting means and receiving therefrom a plurality of output voltage values sequentially inputted at predetermined time intervals and calculating an average value of said plurality of voltage values by using one analog/digital conversion value which is overlapped for a number of said time intervals, said control means being connected to said storing means and to said alarm generating means for comparing said average value with said threshold, recognizing the alarm state of the battery when said average value is smaller than said threshold, and then producing an alarm from said alarm generating means.

2. A battery alarm system according to claim 1, wherein

said storing means is an EEPROM.

3. A battery alarm system according to claim 1, wherein

said alarm generating means includes an alarm with a buzzer.

4. A battery alarm system according to claim 1, wherein

said alarm generating means comprises an indicator for notifying a user of an alarm.