Patent ID: 7830286
Filing Date: 2010-11-09
Classification: H03M

Abstract:
1. An AD converter comprising: an input circuit for taking in an analog signal; a sample-hold circuit for holding the analog signal; an operation circuit for converting the analog signal taken in through the input circuit into a digital signal; and a bus interface for outputting a conversion result of the operation circuit to an external bus, wherein the input circuit includes a pull-down circuit for pulling down an analog signal input-side of the sample-hold circuit whether the analog signal is inputted, and wherein the operation circuit includes a reference voltage conversion result storing register and a check register, the reference voltage conversion result storing register storing a conversion result of an analog reference voltage inputted periodically separately from a conversion result of the analog signal inputted through the pull-down circuit, and the check register writing in and reading out data, which is for checking operation of a signal transfer system including the bus interface, through the bus interface.