VOLTAGE CONTROLLED OSCILLATION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a voltage controlled oscillation circuit which deals with various application systems by widening an oscillation frequency variable range.

SOLUTION: An amplitude control circuit of a voltage controlled oscillation circuit comprises: an amplitude controlled system circuit 20; a reference voltage generation circuit 21 for generating and outputting a reference voltage Vref that becomes a reference of amplitude control; and an operational amplifier circuit 22 to which this reference voltage and an output voltage of the amplitude controlled system circuit are inputted, and which outputs a control voltage Vbp for controlling an amplitude control section 28 of a differential delay cell 23 and an amplitude control section 24 of the amplitude controlled system circuit 20 to eliminate a potential difference between the both. An error between a lower limit value of an oscillation amplitude of the differential delay cell under AC operation and the output voltage of the amplitude controlled system circuit under DC operation is corrected by the control voltage outputted from the operational amplifier circuit.

COPYRIGHT: (C)2005,JPO&NCIPI