| 摘要 |
There is provided a buffer circuit that can deal with input and output signals having a large voltage swing. Such a buffer circuit is designed for outputting an output signal corresponding to an input signal. The buffer circuit includes an input/output circuit for maintaining an output impedance at a constant level, and outputting the output signal having an output voltage which is substantially the same as the input voltage of the input signal, the transistors 434 and 424 that are connected to the respective ends of the input/output circuit in series, where the transistors 434 and 424 protect the input/output circuit by reducing power consumption of the input/output circuit in such a manner as to supply voltages that correspond to the input voltage or the output voltage in terms of level, to the respective ends of the input/output circuit, and the control circuit 420 for (i) when the input voltage is smaller than a reference level, supplying a predetermined constant voltage to the transistor 434 as the base voltage, and (ii) when the input voltage is equal to or larger than the reference level, supplying a voltage that is obtained by decreasing the input voltage by a predetermined voltage to the transistor 434 as the base voltage. Here, the decreased voltage is larger than the predetermined constant voltage.
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