| 摘要 |
A calibration apparatus for a programmable comparator is provided which does not need circuits for offset adjustment and gain adjustment or high precision parts makes possible inexpensive construction of the apparatus itself, and at the same has a wide adjustment range and can carry out high precision calibration. The programmable comparator compares the analog voltage value corresponding to a supplied digital code and the voltage value corresponding to the electric current value of an electric current supplied by a predetermined power supply point, and outputs the result. In the calibration apparatus, the power supply means supplies to a power supply point an electric current having an electric current value indicated, and an electric current detection means converts the electric current value of the electric current flowing through the power supply point to a voltage value, and this value is output to the programmable comparator. The calculation means directs the power supply means to generate an electric current having for each supplied current value "0" or a predetermined electric current value other than "0", and calculates for each supplied current value the actually measured digital code so that the result of the comparison output from the programmable comparator matches. In addition, the calculation means calculates the code correction data from the ideal characteristics between the supplied current value and the digital code, and each supplied current value and each actually measured digital code corresponding to them. According to this, the correction means corrects the digital code supplied to the programmable comparator based on the calculated code correction data.
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