| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent overvoltage applied to a signal buffer circuit due to excessively large or small output and a disturbed signal from load of CCD and the like. <P>SOLUTION: A signal buffer circuit comprises a resistor (R) 12 connected between an input part and an output part of a buffer 11 which is resistance means of high resistance and an impedance variable element (VZ) 13 connected to the output part in series which is impedance variable means with impedance being varied. The impedance variable element 13 is in a low impedance state when the buffer 11 is turned on (the buffer operates), and in a high impedance state when the buffer 11 is turned off (the buffer does not operate: reverse bias is applied between the input and output parts). <P>COPYRIGHT: (C)2012,JPO&INPIT |
