OUTPUT CHANGING METHOD FOR AN A/D CONVERSION APPARATUS AND A/D CONVERSION APPARATUS

摘要

An output changing method of an A/D conversion apparatus is provided. The apparatus includes a pulse delay circuit in which delay units are connected in series, and an encoding circuit which detects the number of stages of the delay units, through which a pulse signal passes during predetermined measurement time, and generates numeric data corresponding to the number of stages. The apparatus receives an analog input signal as power supply voltage of the pulse delay circuit to perform A/D conversion for the analog input signal. The method includes determining whether or not the analog input signal is within an allowable voltage range in which the apparatus operates normally, outputting the numeric data as an A/D conversion value if the analog input signal is within the range, and outputting numeric data formed of a specified value as the A/D conversion value if the analog input signal is not within the range.

主权项

1. An output changing method of an A/D conversion apparatus, the A/D conversion apparatus including: a pulse delay circuit in which a plurality of delay units, which delay a pulse signal by a delay time depending on power supply voltage, are connected in series; and an encoding circuit which detects the number of stages of the delay units, through which the pulse signal passes in the pulse delay circuit during a predetermined measurement time, and generates numeric data corresponding to the number of stages, the A/D conversion apparatus receiving an analog input signal as the power supply voltage of the pulse delay circuit to perform A/D conversion for the analog input signal, comprising;
determining whether or not the analog input signal is within an allowable voltage range in which the A/D conversion apparatus operates normally; outputting the numeric data generated by the encoding circuit as an A/D conversion value of the analog input signal if the analog input signal is within the allowable voltage range; and outputting numeric data formed of a predetermined specified value as the A/D conversion value if the analog input signal is not within the allowable voltage range.