| 摘要 |
PURPOSE:To operate a charge pump circuit in a proper manner by providing an impedance conversion circuit dropping the internal impedance of a reference power source and the 2nd resistance connected to the impedance conversion circuit and the output side of the 1st and 2nd semiconductor switches. CONSTITUTION:The charge pump circuit is provided with the 1st and 2nd semiconductor switches 3 and 4 to which an input signal is supplied, an operational amplifier 6 connected to impedance circuits 7 and 8 between I/O terminals, the 1st resistance 5 connected to the output side of the 1st and 2nd semiconductor switches and the input terminal of the operational amplifier, and a reference power source 9 giving a reference potential to the 2nd input terminal of the operational amplifier. The impedance conversion circuit 11 dropping the internal impedance of the reference power source and the 2nd resistance 13 connected to said impedance conversion circuit and the output side of the 1st and 2nd semiconductor switches are installed in the charge pump circuit. Thus the charge pump circuit properly operates, and a capture range can be expanded with less constant errors. |
