| 摘要 |
PURPOSE:To obtain the supply voltage detection circuit of high precision, and to attain the incorporation into a microcomputer by correcting the variance of the detection voltage of the supply voltage detection circuit by using an EEP ROM and an A/D converter. CONSTITUTION:In order to determine a correction value to correct the variation of the reference voltage generation circuit 9 of the supply voltage detection circuit 5, the input switching circuit 6 of the A/D converter 3 is controlled by a signal (d) from a CPU 1, and the output (b) of the reference voltage generation circuit 9 is inputted to the A/D converter 3, and deviation from prescribed voltage is detected by the CPU 1 based on an A/D-convertion result, and an appropriate resistance value is selected by the signal C, and simultaneously, the result is recorded in the EEP ROM 2. Henceforward, the resistance value is selected according to data stored in the EEP ROM 2. Thus, the supply voltage detection circuit 5 of high precision can be obtained, and the incorporation into the microcomputer is attained. |
