| 摘要 |
<p>PROBLEM TO BE SOLVED: To minimize the characteristic variance of the low-voltage detecting circuit by adjusting the resistance value of a resistance constituting one voltage division side of a 1st resistance means by using selection data written in a specific address of a nonvolatile memory. SOLUTION: (n) Parallel-connected resistances 13-1 to 13-n constitute one voltage division side of the 1st resistance means. Then (n) switch circuits 14-1 to 14-n are composed of, for example, N channel type MOS transistors and connected to the (n) resistances 13-1 to 13-n in series. In the specific address of the flash memory 15, the selection data for selectively turning on and off the switch circuits 14-1 to 14-n are written. The switch circuits 14-1 to 14-n are turned to specific states through hardware once a 1-chip microcomputer is powered on and the resistance values on the voltage are set. Therefore, the resistance values of the resistances constituting the voltage division side of the 1st resistance means can have variance corrected by lots of 1-chip microcomputers.</p> |
