| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce power consumption due to counter operation without dropping bit accuracy, in a reference signal comparison type AD conversion method. <P>SOLUTION: For the same signal, data for an upper N-M bit portion are obtained by an AD conversion process at N-M bit accuracy in first processing, and data for a lower M bit portion are obtained by AD conversion processing at N bit accuracy as for 1 LSB portion at N-M bit accuracy that cannot be decomposed by resolution at the first N-M bit accuracy in second processing. For both the first and second conversion processing, a reference signal is made to change up to a full range portion of AD conversion. A counter part is operated in an anterior half period (or posterior half period) until a comparison result in the full range portion of the AD conversion is inverted in the first processing. In the second processing, the counter part is operated in a period between a point at which the reference signal reaches a level equivalent to the lower limit or the upper limit of the 1 LSB portion at the N-M bit accuracy to which AD conversion data of a processing object signal belongs and a point at which the comparison result is inverted. <P>COPYRIGHT: (C)2011,JPO&INPIT |
