| 摘要 |
PROBLEM TO BE SOLVED: To suppress variation of a delay time of a logic circuit using a MOS transistor. SOLUTION: A phase difference is detected by a phase comparator 2, between oscillation output of a ring oscillator 1 using a delay element which is constituted by the same MOS transistor as that of an internal MOS type logic circuit requiring characteristic adjustment, and prescribed reference clock input 10. A back gate voltage of the MOS transistor is generated and controlled by a back gate voltage generation circuit 3 corresponding to the phase difference. Consequently, the characteristics including the delay time of the internal logic circuit can be constantly and uniformly controlled. Particularly, a logic circuit element requires adjustment of the delay time in a semiconductor IC, and is actually used as the delay element 100 constituting the ring oscillator 1. Eventually, a difference of effect due to type of logic circuit to back gate voltage control can be reduced. COPYRIGHT: (C)2006,JPO&NCIPI
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