| 摘要 |
An object is to provide an A/D converter which uses a plurality of A/D converter circuits and can lower the A/D conversion accuracy in the A/D converter circuit for a lower digit by employing a cyclic A/D conversion scheme for an upper digit thereof. An A/D converter 101 comprises a first cyclic A/D converter circuit 103 and an A/D converter circuit 105. The A/D converter 101 includes a record circuit 107 for storing conversion results from the A/D converter circuits 103, 105. The record circuit 107 includes an upper-bit record circuit 107a and a lower-bit circuit 107b. The cyclic A/D converter circuit 103 receives an analog value SA and generates a first digital value SD1 indicating the analog value SA and a residue value RD. The A/D converter circuit 105 receives the residue value RD and generates a second digital value SD2 having lower M bits indicating the residue value RD. The conversion accuracy in the A/D converter circuit 105 can be lowered to 1/2 L that in the A/D converter circuit 103. |
