To provide a VCO circuit which can obtain the oscillation of a high frequency and subtly controls the frequency by means of input voltage.
A voltage current conversion part 10 converting input voltage Vin into current, a charge/discharge part 20 charging/discharging a capacitor C with current proportional to a current value converted in the voltage current conversion part 10 and a charge/discharge switch part 30 detecting the voltage of the capacitor C and comparing detection voltage with prescribed reference voltage so as to switch the charging and discharging of the charge/discharge part 20 are provided for the VCO circuit. The voltage current conversion part 10 is constituted of a first voltage current conversion circuit converting voltage into current corresponding to input voltage Cin and a second voltage current conversion circuit converting voltage into current corresponding to the output voltage V1 of the constant voltage circuit 11. The capacitor C is charged/ discharged with current proportional to the sum of currents converted by both voltage current conversion circuits.
KITADOU MASAHARU
ITO HISAHARU
SAKAMOTO HIDEO
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