Memory backup battery system

Abstract

Abstract PURPOSE:To protect information stored in a RAM against long term power supply interruption, to reduce the size of the system through utilization of a small capacity primary battery, to reduce the frequency of replacement of the primary battery and the maintenance cost thereof, and to enhance the reliability of the system by connecting primary and secondary batteries in parallel with the circuit as a backup power supply for a RAM. CONSTITUTION:A power supply 1 feeds power to a RAM 2 and also charges a secondary battery V2. Upon interruption of the power supply 1, either a secondary battery section 20 or a primary battery section 10 having higher battery voltage begins to feed current. Upon restart of the power supply 1, a secondary battery voltage drop detecting/indicating section 21 detects voltage of the secondary battery V2 which is then compared with the reference voltage of a comparator Z2 and if it is lower than the reference voltage, voltage drop of the secondary battery V2 is indicated. A primary battery voltage drop detecting/indicating section 11 detects voltage of the primary battery V1 which is then compared with the reference voltage of a comparator Z1 and if it is lower than the reference level, voltage drop of the primary battery V1 and request for battery change are indicated.

Inventors

• 👤 Yoshio Yamamoto
• 👤 山本　良男

Bibliographic Details