| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the service life of a backup battery itself from being unnecessarily shortened by preventing the backup battery from being degraded, by stopping the backup function when a first memory cell holds no information. SOLUTION: The positive pole of a backup battery 9 is connected to the collector of an NPN transistor TR1 and the emitter of the NPN transistor TR1 is connected to the anode of a Schottky diode D5 so that the voltage of the positive pole of the backup battery 9 can be applied to the anode of the Schottky diode D5 when the base of the NPN transistor TR1. Namely, when data are stored in a DRAM 2, the voltage is applied through the NPN transistor TR1 to the anode of the Schottky diode D5 and a current flows, but oppositely, when data are not stored, since no voltage is applied to the anode of the diode D5, no current flows from he backup battery 9.</p> |
