| 摘要 |
PROBLEM TO BE SOLVED: To provide a current supply circuit and an AD converter circuit which reduce an unnecessary bias current while maintaining circuit performance by securing a necessary bias current in the AD converter circuit and other functional circuits. SOLUTION: The bias current is supplied from bias current supply circuits B1 to B15 to comparators C1 to C15 in a parallel-type AD conversion circuit. The bias current supply circuits B1 to B5 are provided with bias current setting terminals (Vb), and bias voltage lines N1 to N15 are connected with them. Bias voltages VA, VB are individually set via switch parts SW-A, SW-B, and the adjacent wiring patterns are connected by resistive elements R1 to R14. A sufficient bias current is secured and a conversion rate is maintained in a comparator functioning within a voltage fluctuation range of input voltage VIN in an AD conversion operation. The bias current is restricted and an operation becomes a low current consumption operation in a comparator functioning outside the voltage fluctuation range. COPYRIGHT: (C)2004,JPO
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