| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a voltage controlled oscillator capable of controlling a frequency range over a wide band even though power supply potential is low, a voltage controlled oscillating method, a PLL circuit using it and communication equipment using the PLL circuit. <P>SOLUTION: This voltage controlled circuit is provided with an inductor circuit 7 having at least one inductor 1, 2, a variable capacitance circuit 10 having varactors 8 and 9, the capacitance of which changes due to applied voltage and having blocking capacitors 15 and 16 for interrupting direct current components at both ends, a negative resistive circuit 13, and a switch 19 which can change reference potential to feed the changed reference potential to one side between varactors 8 and 9, wherein the inductor circuit 7, the variable capacitance circuit 10 and the negative resistive circuit 13 are connected parallel, and control potential in the range from ground potential to power supply potential for feedback controlling an oscillation frequency is inputted to the other side of the varactors 8 and 9. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
