| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit for setting the threshold of an input buffer at a desired value while suppressing power consumption. SOLUTION: The threshold setting circuit includes a first threshold control circuit for controlling the threshold voltage of a buffer circuit, a reference buffer circuit having the characteristics substantially identical to those of the buffer circuit, a second threshold control circuit having the characteristics substantially identical to those of the first threshold control circuit and controlling the threshold voltage of the reference buffer circuit depending on a digital signal, and a digital control circuit for supplying a digital signal to the second threshold control circuit, wherein the digital control circuit monitors a differential voltage between the threshold voltage of the reference buffer circuit and a predetermined reference voltage while changing the digital signal, stores the value of the digital signal when the differential voltage becomes substantially zero, and sets the threshold voltage of the buffer circuit by supplying a digital signal having the value identical to the stored value to the first threshold control circuit. COPYRIGHT: (C)2009,JPO&INPIT
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