| 摘要 |
<p>PURPOSE:To narrow down the package space of a microcomputer and to reduce a leak current due to a rise in outside humidity by molding a backup power source with resin integrally with the microcomputer body. CONSTITUTION:A internal memory backup miniature battery 3 with a holder and an electronic switch 5 which is controlled by a microcomputer chip 4 and switches power supply to an external power source or the miniature battery 3 are packaged together in the CMOS one-chip microcomputer main body 1 together with the microcomputer chip 1. Further, a reverse current preventing circuit is incorporated in the microcomputer chip 4. A voltage drop detecting circuit 2 detects external power supply and informs the microcomputer chip 4 of that. The microcomputer chip 4 drives the electronic switch 5 and switch the power supply to the external power source by disconnecting the power supply from the miniature battery 3.</p> |
