| 摘要 |
PROBLEM TO BE SOLVED: To secure a wide dynamic range for an input control voltage signal in spite of low voltage driving and to reduce frequency fluctuation against the fluctuation of power supply voltage by receiving the control voltage signal, supplying power through an output to a power reception line corresponding to this signal and controlling the oscillation frequency of the oscillation circuit. SOLUTION: An oscillation frequency control circuit 11 is a CMOS type voltage follower, the control voltage signal for controlling the frequency from the outside is inputted by an input terminal 13 connected to the gate of FET Q1 and while connecting the gate of FET Q2 to an output terminal 13b, feedback is performed. Thus, since the output side of the oscillation frequency control circuit 11 is fed back to the input side, the output voltage gets equal with the input voltage, a current value generated on a power reception line Vp becomes a current value corresponding to the control voltage value, power is supplied to a ring oscillator 3 and its frequency is controlled. Thus, the oscillation frequency of the ring oscillator 3 is hardly affected by the fluctuation of power supply voltage. |
