| 摘要 |
PROBLEM TO BE SOLVED: To provide a reference signal fault discrimination apparatus for a digital / analog converter capable of discriminating the fault of a reference signal with high accuracy. SOLUTION: The reference signal fault discrimination apparatus for a digital / analog converter includes: a comparator (1) for comparing the signal level of a reference signal (2) of a digital / analog converter with a reference voltage; a first counter (10) for counting a frequency of a pulse output (1a) outputted from the comparator; a second counter (11) for counting a pulse width of the pulse output (1a); first comparators (12, 13) for discriminating whether the count result of the first counter (10) is within a range between a prescribed upper limit and a prescribed lower limit; and second comparators (14, 15) for discriminating whether the count result of the second counter (11) is within a range between a prescribed upper limit and a prescribed lower limit. When either of the frequency or the pulse width of the pulse output (1a) is deviated from the upper limit or the lower limit, the reference signal fault discrimination apparatus discriminates that the reference signal (2) is faulty. COPYRIGHT: (C)2004,JPO
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