Injection-Locked Oscillator Circuit

• US 20080030282A1
• Filed: 09/10/2004
• Published: 02/07/2008
• Est. Priority Date: 09/29/2003
• Status: Active Grant

• Current Assignee: Maxlinear Incorporated
• Original Assignee: Lantiq Deutschland GMBH (Intel Corporation)
• Inventors: Tiebout, Marc, Maget, Judith
• Granted Patent: US 7,592,875 B2
• Time in Patent Office: Days
• US Class Current: 331/46
• CPC Class Codes: H03B 27/00 Generation of oscillations providing a plurality of outputs of the same frequency but differing in phase, other than merely two anti-phase outputs
• 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: H03K 3/354 Astable circuits
• CPC Class Codes: H03L 7/24 using a reference signal directly applied to the generator

Abstract

An ILO circuit has a plurality of oscillator stages which are coupled to one another by means of a “tank lock” coupling. The coupling leads to an improved synchronization of the individual oscillator stages and thus to a reduced phase noise. Any desired LC oscillator topology can be used, not just the topology with PMOS and NMOS transistors. It is also possible to use SOI transistors, that is to say transistors formed on an SOI substrate. The bulk terminals of the transistors may be coupled not only to a supply voltage but, for example, also to a center potential, a reference voltage source, to ground, in floating fashion and/or to the source terminal.

Claims

1-12. -12. (canceled)

13. An injection-locked oscillator circuit comprising at least two oscillator stages, each oscillator stage comprising:

an inductance;

a capacitance connected in parallel with the inductance;

at least one output node;

a coupling-switching element subcircuit comprising at least one coupling-switching element which is coupled in parallel with the inductance and the capacitance in such a way that in each case precisely one coupling-switching element is present serially; and

at least one input terminal formed by means of the control terminal of the coupling-switching element;

wherein the oscillator stages of the injection-locked oscillator circuit are coupled by means of the coupling-switching element subcircuits.

14. The injection-locked oscillator circuit as claimed of claim 13, wherein each oscillator stage has two output terminals at which signals that are differential with respect to one another are present.

15. The injection-locked oscillator circuit of claim 13, wherein the coupling-switching element subcircuit has two additional coupling-switching elements which are connected up to one another and are connected in parallel with the coupling-switching elements connected up to one another.

16. The injection-locked oscillator circuit of claim 13, wherein the coupling-switching elements are transistors.

17. The injection-locked oscillator circuit of claim 16, wherein the transistors are NMOS and/or PMOS transistors.

18. The injection-locked oscillator circuit of claim 17, wherein a respective one of the transistors connected in parallel is a PMOS transistor and the other transistor connected in parallel is an NMOS transistor.

19. The injection-locked oscillator circuit of claim 13, wherein the capacitances are formed by means of varactors.

20. The injection-locked oscillator circuit of claim 13, wherein the oscillator stages have an active element.

21. The injection-locked oscillator circuit of claim 13, wherein an even number of oscillator stages are coupled to form an injection-locked oscillator circuit.

22. The injection-locked oscillator circuit of claim 21, wherein the number of input terminals of each oscillator stage is equal to the number of oscillator stages of the injection-locked oscillator circuit.

23. The injection-locked oscillator circuit of claim 22, wherein the injection-locked oscillator circuit has four oscillator stages, each oscillator stage having four input terminals and two output terminals and two of the input terminals being coupled to the output terminals of a preceding oscillator stage of the injection-locked oscillator circuit in the signal flow direction, and the other two input terminals being coupled to the output terminals of the downstream injection-locked oscillator circuit in the signal flow direction.

24. The injection-locked oscillator circuit of claim 13, wherein the injection-locked oscillator circuit has an odd number of oscillator stages.

25. A semiconductor comprising:

a first inductance coupled in parallel with a first capacitance;

a first switching circuit coupled in parallel with the first inductance and capacitance, the first switching circuit having a control terminal configured as a first input;

a second inductance coupled in parallel with a second capacitance;

a second switching circuit coupled in parallel with the second inductance and capacitance, the second switching circuit having a control terminal configured as a second input; and

means for coupling the first and second switching circuits to form an injection-locked oscillator circuit.

26. The circuit of claim 25, wherein the first inductance, first capacitance and first switching circuit form a first oscillator stage and the second inductance, second capacitance and second switching circuit form a second oscillator stage, wherein each oscillator stage has two output terminals with differential signals.

27. The circuit of claim 26, wherein the coupling-switching elements are transistors.

28. The circuit of claim 26, wherein the transistors are NMOS and/or PMOS transistors.

29. The circuit of claim 26, wherein a respective one of the transistors connected in parallel is a PMOS transistor and the other transistor connected in parallel is an NMOS transistor.

30. The circuit of claim 26, wherein the capacitances are formed by means of varactors.

31. The circuit of claim 26, wherein the oscillator stages have an active element.

32. The circuit claim of 26, wherein an even number of oscillator stages are coupled to form an injection-locked oscillator circuit.