Apparatus for detecting A/D converter abnormality
AssigneeDenso Corporation
InventorHideki Kabune
Life of this patent
Estimating the term…
Abstract
An apparatus for detecting an abnormality in an A/D converter has a voltage accumulating capacitor. The apparatus includes a storage circuit which receives analog signals whose range of signal operation voltage when normal is limited to be narrower than the range of input operation voltages, and stores in advance the range of abnormal voltages of digital signals converted by the A/D converter, and determines the A/D converter to be abnormal when the digital signal voltage lies in the range of abnormal voltages. The A/D converter converts the analog signal voltage into a digital signal voltage, and then initializes the analog signal voltage of the capacitor to a voltage in the abnormal voltage range.
Claims18
An apparatus for detecting an A/D converter abnormality comprising:
- an A/D converter having input terminals of one or more channels for inputting analog signal voltages and a capacitor for sample-holding the analog signal voltages, and for AD-converting the analog signal voltages sample-held in the capacitor into digital signal values;
- input means for inputting analog signals to the input terminals of at least one channel, a signal operation voltage range being limited to be narrower than a range of input operation voltages of the A/D converter when the analog signals are normal;
- a storage means storing in advance an abnormality determining range of the digital signal values converted by the A/D converter;
- voltage range setting means for setting the abnormality determining range to values corresponding to a voltage range in an input voltage range of the A/D converter outside the limited range of signal operation voltages;
- means for detecting an A/D converter abnormality to determine an A/D conversion to be abnormal when a value of a digital signal converted from the limited analog signal lies in the abnormality determining range;
- and
- initializing means for initializing the voltage accumulated in the capacitor by a last A/D conversion operation into a voltage that lies within the abnormality determining range at least prior to sample-holding the limited analog input signal voltage in the capacitor.
An apparatus for detecting an A/D converter abnormality comprising:
- an A/D converter having input terminals of two or more channels for inputting analog signal voltages, and for AD-converting the analog signal voltages into digital signal values;
- abnormality detecting voltage forming means for forming a predetermined abnormality detecting voltage from a power source separate from a power source for operating the A/D converter and from a power source for forming a reference voltage that serves as a reference for the A/D conversion;
- ideal value storage means for storing an ideal value of when the abnormality detecting voltage is put to an A/D conversion;
- and
- abnormality detecting means which inputs the abnormality detecting voltage to at least one channel of the A/D converter and compares the A/D-converted value thereof with the ideal value to determine the A/D converter to be abnormal when a difference between the two exceeds a predetermined value.
An apparatus for detecting an A/D converter abnormality which has input terminals of three or more channels for inputting analog signal voltages and for AD-converting the analog signal voltages into digital signal values, the apparatus comprising:
- setting means for setting voltage values of at least two points so that values after an A/D conversion establish a predetermined relationship;
- calculation means for finding a relationship of voltage values of at least the two points from the A/D-converted values of the voltage values of at least the two points;
- and
- abnormality detecting means which compares the calculated relationship of the voltage values of at least the two points with the predetermined relationship, and determines the A/D converter to be abnormal when a difference between the two exceeds a predetermined value.
An apparatus for detecting an A/D converter abnormality comprising:
- an A/D converter having at least one input terminal (AIN1, AIN2) for inputting an analog signal voltage, and for AD-converting a voltage value of the analog signal into a digital signal value;
- a parity calculation circuit for adding a parity bit to an A/D-converted value of the analog signal;
- a converted result storage circuit for storing the A/D-converted value of the analog signal and the parity bit;
- and
- abnormality detecting means for reading the A/D-converted value from the converted result storage circuit, checking the matching of the parity bit, and determining the A/D converter to be abnormal when the parity bit is mismatching.
Dependencies are inferred from the claim text.