To provide a voltage-controlled oscillation circuit that expands variable range of the voltage to be applied to a variable capacitance diode even if the maximum available value of the control voltage generated in a PLL circuit controlling oscillation frequency decreases to low voltage, and has a simple circuit configuration to reduce the size of an oscillator.
The voltage controlled oscillation circuit 1 includes: an oscillation transistor 2; a resonance circuit 13 having a variable capacitance diode 16 and connected to the oscillation transistor 2; a collector resistor RC inserted between a power source terminal T2 to which power source voltage is applied and the ground, and connected in parallel to the variable capacitance diode 16; and a control transistor 21 which is inserted between the ground-side terminal of the collector resistor RC and the ground, and to which control voltage for controlling the oscillation frequency is applied.
| WO/2019/222770 | CIRCUIT WITH SHUNT PATH |
| JP2014506102 | Varicapless tunable oscillator |
Amada Masayuki
Yoshimasa Okada