Battery backup circuit for static ram

Abstract

Abstract PURPOSE:To contrive the reduction of power consumption of a battery without making a constitution complicated by disconnecting a gate circuit transmitting a chip selecting signal when a power source voltage is dropped. CONSTITUTION:When the power source voltage VCC is higher than a prescribed value, the output of a resetting circuit 20 for voltage detection becomes H to turn on a transistor 18, and the chip selecting signal is supplied to a static RAM1 from a system circuit 7 through the gate circuit 14. If the voltage VCC drops due to the disconnection of a power source 4, a battery 5 backs up the RAM1 through a diode 4, and simultaneously the output of the circuit 20 is inverted to L to turn off the transistor 18, and the circuit 14 with a large leak current is disconnected. Consequently the power that the backup battery consumes can be reduced without making the constitution complicated and without uselessly consuming power.

Inventors

• 👤 Shuji Mihashi
• 👤 三橋　修二
• 👤 Hideo Obara
• 👤 秀雄 小原

Bibliographic Details