| 摘要 |
PURPOSE:To obtain a voltage controlled oscillation circuit with a large control range at a high frequency band by providing a current source charging or discharging a load capacitance intermittently between the load capacitance and a switch means forming intermittently a charging or a discharging path depending on an output voltage. CONSTITUTION:A potential a node N1 connected with a load capacitance Co is charged by a P-MOSFET Q1. That is, when the potential of the node n1 is lower than a threshold voltage Vlth of an inverter circuit IV1, an N-MOSFER Q8 is turned off by the action of circuits IV1, IV2 and a discharge circuit comprising the FETs Q6, Q7 is not formed. The said charging current is controlled by an input control voltage Vin and a bias voltage Vb. When the potential of the node N1 reaches the voltage Vlth, the output voltage is inverted, the FET Q8 is turned on to form the discharge, path. Since the discharge current in this case is set to nearly twice the charging current, the potential of the node n1 is lowered along with the same slope as that at the charging. The oscillation is executed by the repetition of the operation above. The oscillation frequency of the oscillation circuit depends on the charge/discharge current controlled by the voltages Vin and Vb.
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