Voltage control oscillator

Abstract

Abstract PURPOSE:To obtain a frequency generating circuit where the frequency adjustment is easy and a frequency inversely proportional to an input DC voltage is generated, by discharging the electric charge of a capacitor by the output of a comparator which inverts the output polarity when the charging voltage of the capacitor exceeds a prescribed voltage. CONSTITUTION:When a capcitor C5 is charged by a current from a constant current source 4 and the charging voltage becomes higher than an input DC voltage Vi from a terminal 1, the output of a comparator 6 is inverted to the H level from the L level. By the H level signal of the comparator 6, an analogue switch 93 is operated through a diode 91, and a monostable multivibrator 7 is triggerred. A short time constant t0 is set to the monostable multivibrator 7, and the H level signal is outputted only in this time t0 to drive a T type FF8 and hold the analogue switch 93 through a diode 92. Charge of the C5 is discharged by the operation of the analogue switch 93, and the output of the comparator 6 is set to the L level, and the analogue switch 93 is opened to charge the C5 again. By repeating this operation, the FF8 is driven by the signal of a frequency inversely proportional to the voltage Vi, and an oscillation signal of 50% duty is outputted from the FF8.

Inventors

• 👤 Tadashi Nose

Bibliographic Details