| 摘要 |
PROBLEM TO BE SOLVED: To perform incorporation inside an LSI by lowering the capacitance value of a capacitor C and to adjust the characteristics by a current through turning a resistor R and the C which are to be a filter to a parameter depending on the current. SOLUTION: This filter circuit is constituted by connecting output signals from an input circuit via the resistor R1 and the time constant circuit of a first capacitor C1 to a current conversion part 11. One end of the resistor R1 and one end of the capacitor C1, the other end of which is grounded are respectively connected to the output part of the two systems of the input circuit, one end of the capacitor is inputted to the current conversion part 11 and the output of the current conversion part 11 and the output of the other end of the resistor are synthesized by a synthesis part and outputted. Also, by using a filter circuit, the output current of the synthesis part is supplied to a current- controlled oscillator 12, whose oscillation frequency is controlled by an input current value and this PLL circuit is constituted. |
