| 摘要 |
<p>PURPOSE:To securely preserve the internal part of external RAM by interrupting an external RAM backup circuit and external RAM from the other circuit by means of a battery switch which is activated by a computer when a main power source is turned off or it is down. CONSTITUTION:A main power source circuit 17 supplies power to the micro computer 6, a display tube 5, a printer 11 and external RAM 12. External RAM 12 is supplied with the power of the circuit 17 through a backup power circuit 18. When an AC adapter is connected to a jack 2 and external power is supplied, a main battery 1 is prevented from being used. The external RAM backup circuit 13 supplying power to external RAM by a backup battery 15 is provided. When the circuit 17 is turned off or when it is down the circuit composed of the circuit 13 and external RAM 12 is interrupted from the other circuit by the battery switch circuit 14 which is activated by a computer 6.</p> |
