Highly-linear signal-modulated voltage controlled oscillator

• US 7,102,454 B2
• Filed: 01/31/2005
• Issued: 09/05/2006
• Est. Priority Date: 08/04/2004
• Status: Active Grant

• Current Assignee: VIA Technologies Incorporated (VIA Technologies)
• Original Assignee: VIA Technologies Incorporated (VIA Technologies)
• Inventors: Sze, Bour-Yi, Ho, Chih-Long, Cheng, Nean-Chu
• Primary Examiner(s): MIS, DAVID C
• Application Number:
  US11/047,835
• Publication Number:
  US 20060028281A1
• Time in Patent Office: 582 Days
• Field of Search: 331/17, 331/18, 331/23, 331/25, 331/36.C, 331/117.R, 331/117.FE, 331/117.D, 331/177.V, 331/179, 332/127, 332/141
• US Class Current: 331/117.0FE
• CPC Class Codes: H03B 2201/0266 the means comprising a transistor
• CPC Class Codes: H03B 5/1212 the amplifier comprising a pair of transistors, wherein an output terminal of each being connected to an input terminal of the other, e.g. a cross coupled pair
• CPC Class Codes: H03B 5/1215 the current source or degeneration circuit being in common to both transistors of the pair, e.g. a cross-coupled long-tailed pair
• CPC Class Codes: H03B 5/1228 the amplifier comprising one or more field effect transistors
• CPC Class Codes: H03B 5/1243 the means comprising voltage variable capacitance diodes
• CPC Class Codes: H03B 5/1265 switched capacitors
• CPC Class Codes: H03C 3/0958 applying frequency modulation by varying the characteristics of the voltage controlled oscillator
• CPC Class Codes: H03J 5/244 using electronic means
• CPC Class Codes: H03L 2207/06 Phase locked loops with a controlled oscillator having at least two frequency control terminals
• CPC Class Codes: H03L 7/099 concerning mainly the controlled oscillator of the loop

Abstract

A VCO system embodying the features of the present invention includes a frequency tuning circuit, a modulation circuit coupled in a parallel fashion with the frequency tuning circuit, a band tuning circuit coupled with the frequency tuning circuit in a parallel fashion having at least one switching circuit, a core circuit coupled with the frequency tuning circuit, the modulation circuit, and the band tuning circuit, wherein upon asserting a switching signal and upon adjusting a frequency turning signal, a frequency tuning bias signal, and a band tuning signal, the switching circuit is enabled for configuring the band tuning circuit to join the frequency tuning circuit for adjusting a predetermined output frequency based on a total inductance and a total capacitance provided by the core circuit, the frequency tuning circuit, the modulation circuit and the band tuning circuit.

Claims

1. A voltage controlled oscillator system comprising:

a frequency tuning circuit for receiving a frequency turning signal and a frequency tuning bias signal;

a modulation circuit coupled in a parallel fashion with the frequency tuning circuit;

at least one band tuning circuits coupled with the frequency tuning circuit in a parallel fashion having at least one switching circuit for receiving at least one band tuning signal and at least one switching signal; and

a core circuit coupled with the frequency tuning circuit, the modulation circuit, and the band tuning circuit for providing a first output and a second output that are complementary to each other,

wherein the core circuit has at least one inductance module for providing a predetermined inductance,

wherein upon asserting the switching signal, the switching circuit is enabled for configuring the band tuning circuit to join the frequency tuning circuit for determining a predetermined output frequency based on a total inductance and a total capacitance provided by the core circuit, the frequency tuning circuit, the modulation circuit and the band tuning circuit upon adjusting the frequency tuning signal, the frequency tuning bias signal, and the band tuning signal, and

wherein all elements of the voltage controlled oscillator system are arranged in a substantially symmetrical fashion.

2. The system of claim 1, wherein the frequency tuning circuit is integrated with the modulation circuit.

3. The system of claim 2, wherein the integrated frequency turning and modulation circuits further include:

a first capacitor and a second capacitor coupled to the first and the second outputs on their first ends respectively;

a first group of varactors having a first varactor and a second varactor coupled in series with and between the first and second capacitors with a mid point between the first and second varactors coupled to the frequency turning signal;

a resistor group having a first resistor and a second resistor coupled in series with and between the first and second capacitors with a mid point between the first and second resistors coupled to the frequency tuning bias signal; and

a second group of varactors having a third varactor and a fourth varactor coupled in series with and between the first and second capacitors with a mid point between the third and fourth varactors coupled to the modulation signal,

wherein the first and second varactor groups and the resistor group are coupled in a parallel fashion and together coupled in series with the first and second capacitors between their second ends.

4. The system of claim 1, further comprising:

a phase-locked loop frequency synthesizer for providing the frequency tuning signal based on at least one of the outputs; and

a control circuit coupled with the modulation circuit for providing the modulation signal and the frequency tuning bias signal.

5. The system of claim 1, wherein the frequency tuning circuit has the modulation circuit separated from a frequency tuning module, which are coupled in a parallel fashion.

6. The system of claim 5, wherein the frequency tuning module further includes:

a first capacitor and a second capacitor coupled to the first and the second outputs on their first ends respectively;

a first varactor and a second varactor coupled in series with and between the first and second capacitors with a mid point between the first and second varactors coupled to the frequency turning signal; and

a first resistor and a second resistor coupled in series with and between the first and second capacitors with a mid point between the first and second resistors coupled to the frequency tuning bias signal,

wherein the first and second resistors are coupled in a parallel fashion with the first and second varactors and together coupled to the first and second capacitors in series between their second ends.

7. The system of claim 5, wherein the modulation circuit further includes:

a first capacitor and a second capacitor coupled in series and to the first and the second outputs on their first ends respectively;

a first varactor and a second varactor coupled in series with and between the first and second capacitors with a mid point between the first and second varactors coupled to the modulation signal; and

a first resistor and a second resistor coupled in series with and between the first and second capacitors with a mid point between the first and second resistors coupled to an electrical ground,

wherein the first and second resistors are coupled in a parallel fashion with the first and second varactors and together coupled to the first and second capacitors in series between their second ends.

8. The system of claim 1, wherein the band tuning circuit further includes:

a first and a second capacitance modules having a first and second predetermined capacitances coupled to the first and second outputs on their first ends,

a first and second resistors coupled in series and further coupled serially between second ends of the first and second capacitance modules with a mid point between the two resistors controlled by the band tuning signal; and

a first and a second switches coupled in series and further coupled serially between second ends of the first and second capacitance modules with a mid point between the two switches coupled to an electrical ground,

wherein when the switching signal is applied to gates of the switches, the first and second capacitance modules are coupled in a serial fashion.

9. The system of claim 8, wherein the capacitance modules are varactors.

10. The system of claim 1 further comprising a core circuit coupled with both the frequency tuning circuit and the band tuning circuit in a parallel fashion for providing an oscillation mechanism.

11. The system of claim 10, wherein the core circuit further includes:

at least one PMOS cross-coupled transistor structure having at least a pair of cross-coupled PMOS transistors with sources thereof coupled to a power source; and

at least one NMOS cross-coupled transistor structure having at least a pair of cross-coupled NMOS transistors with sources thereof coupled to an electrical ground,

wherein drains of the PMOS and NMOS transistors are coupled to either the first or second outputs, and

wherein a gate of a PMOS or NMOS transistor is cross-coupled to a drain of another PMOS or NMOS transistor of the corresponding pair.

12. The system of claim 10 wherein the core circuit further includes:

at least one NMOS cross-coupled transistor structure having at least a first and second cross-coupled NMOS transistors with sources thereof coupled to an electrical ground, and drains thereof coupled to the first and second outputs;

a first inductance module coupled between a power source and the first output;

a second inductance module coupled between the power source and the second output,

wherein gates of the first and second NMOS transistor are cross-coupled to drains of the second and first NMOS transistor respectively.

13. The system of claim 10 wherein the core circuit further includes:

at least one PMOS cross-coupled transistor structure having at least a first and second cross-coupled PMOS transistors with sources thereof coupled to an power source, and drains thereof coupled to the first and second outputs;

a first inductance module coupled between a ground and the first output;

a second inductance module coupled between the ground and the second output,

wherein gates of the first and second PMOS transistors are cross-coupled to drains of the second and first NMOS transistors respectively.

14. The system of claim 1 further comprising a core circuit coupled with both the frequency tuning circuit and the band tuning circuit in a parallel fashion for providing an oscillation mechanism, the core circuit having at least one cross-coupled transistor structure for providing a negative resistance and at least one inductance module symmetrically positioned.

15. A voltage controlled oscillator system comprising:

a frequency tuning circuit for receiving a frequency turning signal and a frequency tuning bias signal;

a modulation circuit coupled in a parallel fashion with the frequency tuning circuit;

at least one band tuning circuits coupled with the frequency tuning circuit in a parallel fashion having at least one switching circuit for receiving at least one band tuning signal and at least one switching signal;

a phase-locked loop frequency synthesizer for providing the frequency tuning signal based on at least one of the outputs;

a control circuit coupled with the modulation circuit for providing the modulation signal and the frequency tuning bias signal; and

a core circuit coupled with the frequency tuning circuit, the modulation circuit, and the band tuning circuit for providing a first output and a second output that are complementary to each other,

wherein the core circuit has at least one inductance module for providing a predetermined inductance,

wherein upon asserting the switching signal, the switching circuit is enabled for configuring the band tuning circuit to join the frequency tuning circuit for determining a predetermined output frequency based on a total inductance and a total capacitance provided by the core circuit, the frequency tuning circuit, the modulation circuit and the band tuning circuit upon adjusting the frequency tuning signal, the frequency tuning bias signal, and the band tuning signal, and

wherein all elements of the voltage controlled oscillator system are arranged in a substantially symmetrical fashion.

16. The system of claim 15, wherein the frequency tuning circuit is integrated with the modulation circuit to further include:

a first capacitor and a second capacitor coupled to the first and the second outputs on their first ends respectively;

a first group of varactors having a first varactor and a second varactor coupled in series with and between the first and second capacitors with a mid point between the first and second varactors coupled to the frequency turning signal;

a resistor group having a first resistor and a second resistor coupled in series with and between the first and second capacitors with a mid point between the first and second resistors coupled to the frequency tuning bias signal; and

a second group of varactors having a third varactor and a fourth varactor coupled in series with and between the first and second capacitors with a mid point between the third and fourth varactors coupled to the modulation signal,

wherein the first and second varactor groups and the resistor group are coupled in a parallel fashion and together coupled in series with the first and second capacitors between their second ends.

17. The system of claim 15, wherein the frequency tuning circuit has the modulation circuit separated from a frequency tuning module, which are coupled in a parallel fashion.

18. The system of claim 17, wherein the frequency tuning module further includes:

a first capacitor and a second capacitor coupled to the first and the second outputs on their first ends respectively;

a first varactor and a second varactor coupled in series with and between the first and second capacitors with a mid point between the first and second varactors coupled to the frequency turning signal; and

a first resistor and a second resistor coupled in series with and between the first and second capacitors with a mid point between the first and second resistors coupled to the frequency tuning bias signal,

wherein the first and second resistors are coupled in a parallel fashion with the first and second varactors and together coupled to the first and second capacitors in series between their second ends.

19. The system of claim 17, wherein the modulation circuit further includes:

a first capacitor and a second capacitor coupled in series and to the first and the second outputs on their first ends respectively;

a first varactor and a second varactor coupled in series with and between the first and second capacitors with a mid point between the first and second varactors coupled to the modulation signal; and

a first resistor and a second resistor coupled in series with and between the first and second capacitors with a mid point between the first and second resistors coupled to an electrical ground,

wherein the first and second resistors are coupled in a parallel fashion with the first and second varactors and together coupled to the first and second capacitors in series between their second ends.

20. The system of claim 15, wherein the band tuning circuit further includes:

a first and a second capacitance modules having a first and second predetermined capacitances coupled to the first and second outputs on their first ends,

a first and second resistors coupled in series and further coupled serially between second ends of the first and second capacitance modules with a mid point between the two resistors controlled by the band tuning signal; and

a first and a second switches coupled in series and further coupled serially between second ends of the first and second capacitance modules with a mid point between the two switches coupled to an electrical ground,

wherein when the switching signal is applied to gates of the switches, the first and second capacitance modules are coupled in a serial fashion.

21. A voltage controlled oscillator system comprising:

a frequency tuning circuit for receiving a frequency turning signal and a frequency tuning bias signal;

a modulation circuit coupled in a parallel fashion with the frequency tuning circuit;

at least one band tuning circuits coupled with the frequency tuning circuit in a parallel fashion having at least one switching circuit for receiving at least one band tuning signal and at least one switching signal, the band tuning circuit further including;

a first and a second capacitance modules having a first and second predetermined capacitances coupled to the first and second outputs on their first ends,

a first and second resistors coupled in series and further coupled serially between second ends of the first and second capacitance modules with a mid point between the two resistors controlled by the band tuning signal; and

a first and a second switches coupled in series and further coupled serially between second ends of the first and second capacitance modules with a mid point between the two switches coupled to an electrical ground, wherein when the switching signal is applied to gates of the switches, the first and second capacitance modules are coupled in a serial fashion;

a phase-locked loop frequency synthesizer for providing the frequency tuning signal based on at least one of the outputs;

a control circuit coupled with the modulation circuit for providing the modulation signal and the frequency tuning bias signal; and

a core circuit coupled with the frequency tuning circuit, the modulation circuit, and the band tuning circuit for providing a first output and a second output that are complementary to each other,

wherein the core circuit has at least one inductance module for providing a predetermined inductance,

wherein upon asserting the switching signal, the switching circuit is enabled for configuring the band tuning circuit to join the frequency tuning circuit for determining a predetermined output frequency based on a total inductance and a total capacitance provided by the core circuit, the frequency tuning circuit, the modulation circuit and the band tuning circuit upon adjusting the frequency tuning signal, the frequency tuning bias signal, and the band tuning signal, and

wherein all elements of the voltage controlled oscillator system are arranged in a substantially symmetrical fashion.

22. The system of claim 21, wherein the frequency tuning circuit is integrated with the modulation circuit to further include:

a first capacitor and a second capacitor coupled to the first and the second outputs on their first ends respectively;

a first group of varactors having a first varactor and a second varactor coupled in series with and between the first and second capacitors with a mid point between the first and second varactors coupled to the frequency turning signal;

a resistor group having a first resistor and a second resistor coupled in series with and between the first and second capacitors with a mid point between the first and second resistors coupled to the frequency tuning bias signal; and

a second group of varactors having a third varactor and a fourth varactor coupled in series with and between the first and second capacitors with a mid point between the third and fourth varactors coupled to the modulation signal,

wherein the first and second varactor groups and the resistor group are coupled in a parallel fashion and together coupled in series with the first and second capacitors between their second ends.

23. The system of claim 21, wherein the frequency tuning circuit has the modulation circuit separated from a frequency tuning module, which are coupled in a parallel fashion, wherein the frequency tuning module further includes:

a first capacitor and a second capacitor coupled to the first and the second outputs on their first ends respectively;

a first varactor and a second varactor coupled in series with and between the first and second capacitors with a mid point between the first and second varactors coupled to the frequency turning signal; and

a first resistor and a second resistor coupled in series with and between the first and second capacitors with a mid point between the first and second resistors coupled to the frequency tuning bias signal,

wherein the first and second resistors are coupled in a parallel fashion with the first and second varactors and together coupled to the first and second capacitors in series between their second ends;

wherein the modulation circuit further includes;

a first capacitor and a second capacitor coupled in series and to the first and the second outputs on their first ends respectively;

a first varactor and a second varactor coupled in series with and between the first and second capacitors with a mid point between the first and second varactors coupled to the modulation signal; and

a first resistor and a second resistor coupled in series with and between the first and second capacitors with a mid point between the first and second resistors coupled to an electrical ground,

wherein the first and second resistors are coupled in a parallel fashion with the first and second varactors and together coupled to the first and second capacitors in series between their second ends.

24. The system of claim 21 further comprising a core circuit coupled with both the frequency tuning circuit and the band tuning circuit in a parallel fashion for providing an oscillation mechanism, the core circuit having at least one cross-coupled transistor structure for providing a negative resistance and at least one inductance module symmetrically positioned.