| 摘要 |
PURPOSE:To set the threshold voltage of an input circuit to a desired value easily, by setting the output of a D/A comparator circuit by a program, and regarding its output value as a reference voltage value for the operation of a comparator. CONSTITUTION:A comparison input voltage is led from an input terminal 10 to the comparator circuit 11. The output voltage of the D/A converter circuit 12 is led as the reference input. This output voltage is given through a data table 13 by a digital input set by a user's in-use program when an integrated circuit is used. When the input voltage is lower than the output voltage, the comparison output of the comparator 11 is at a power supply potential VDD. When the input voltage exceeds the output voltage, on the other hand, the comparison output is at the earth potential. This operation means that the threshold voltage of the input circuit is set to the desired value. |
