Patent ID: 8410964

Claim:
An AD conversion circuit that receives analog signals of various types and selects the analog signals of one type, and converts the selected analog signals of the one type to digital signals, the AD conversion circuit comprising: a holding portion configured to store sequence information, signal selection information and time information so as to be associated with one another; a sequencing counter configured to be initialized by receiving a timing signal output at a predetermined period and to start counting upon receipt of a matching signal to obtain a sequencing counter count value; a time period counter configured to be initialized by receiving the timing signal or the matching signal and to count a time with a supplied clock as a time period counter count value; a comparator configured to generate the matching signal when the time information in the holding portion matches the time period counter count value after comparing the time information in the holding portion with the time period counter count value by referring to the sequence information in the holding portion using the sequencing counter count value; a selecting portion configured to select the analog signals of the one type corresponding to the signal selection information obtained by referring to the sequence information in the holding portion using the sequencing counter count value out of the analog signals of various types; and an AD converter configured to convert the analog signal of the one type selected by the selecting portion from analog to digital.