| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable a capacitor to be switched over while retaining an electric potential. <P>SOLUTION: Letting an electric potential applied to a base of a PNP transistor 31, i.e., an electric potential of a divided output of a divider circuit 32, be a "specified potential", an output capacitance select signal switching circuit 25 converts an output form thereof into an output for the source when the electric potential of an input signal is equal to or greater than the specified potential, and converts the output form thereof into a combined output of diode sink and high impedance relative to a reference potential (GND) when the electric potential of the input signal is less than the specified potential. Therefore, even if the potential Cgm at a negative electrode end of a capacitor 21G drops below the reference potential (GND), the OFF states of FETs 22G and 23G can be maintained, consequently allowing the capacitor 21G to be switched over while being maintained at high potential. <P>COPYRIGHT: (C)2012,JPO&INPIT |
