Frequency adjustment techniques in coupled LC tank circuits

• US 20070018739A1
• Filed: 07/19/2005
• Published: 01/25/2007
• Est. Priority Date: 07/19/2005
• Status: Active Grant

• Current Assignee: Intellectual Ventures Holding 81 LLC (Intellectual Ventures LLC)
• Original Assignee: LC Tank LLC
• Inventors: Gabara, Thaddeus
• Granted Patent: US 7,508,280 B2
• Time in Patent Office: Days
• US Class Current: 331/167
• CPC Class Codes: G06F 1/10 Distribution of clock signals , e.g. skew
• CPC Class Codes: H03B 2200/0076 Power combination of several oscillators oscillating at the same frequency
• 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 5/1228 the amplifier comprising one or more field effect transistors
• CPC Class Codes: H03B 5/1243 the means comprising voltage variable capacitance diodes

Abstract

CMOS LC tank circuits and flux linkage between inductors can be used to distribute and propagate clock signals over the surface of a VLSI chip or μprocessor. The tank circuit offers an adiabatic behavior that recycles the energy between the reactive elements and minimizes losses in a conventional sense. Flux linkage can be used to orchestrate a number of seemingly individual and distributed CMOS LC tank circuits to behave as one unit. Several frequency-adjusting techniques are presented which can be used in an distributed clock network environment which includes an array of oscillators. A passive flux linkage, mechanical, and finite state machine technique of frequency adjustment of oscillators are described.

Claims

1. An oscillator frequency adjustment apparatus comprising;

a first output and a second output,

one or more transformers where each transformer comprises at least two coils,

an oscillator circuit comprising;

at least one coil from the transformer,

at least one capacitor,

at least one regenerative circuit,

a means of coupling the coils, capacitors and regenerative circuits to form the oscillator circuit, wherein

the oscillator circuit is coupled to the first and second output, at least one adjustable tank circuit comprising;

the second coil of the transformer, and

at least one adjustable capacitor, wherein the coil from the oscillator circuit has a flux linkage with the second coil from the adjustable tank circuit, whereby adjusting the one adjustable capacitor changes the frequency of operation of the apparatus.

2. The apparatus of claim 1 wherein;

the one adjustable capacitor comprises;

a varactor.

3. The apparatus of claim 1 wherein;

the one adjustable capacitor comprises;

a digitally weighted capacitor.

4. The apparatus of claim 1 wherein;

the one adjustable capacitor comprises;

an enhancement mode transistor capacitor made adjustable by a DC voltage.

5. The apparatus of claim 1 wherein;

the one adjustable capacitor comprises;

a depletion mode transistor capacitor made adjustable by a DC voltage.

6. The apparatus of claim 1 further comprising;

the fabrication of the oscillator on a first substrate,

the fabrication of the adjustable tank circuit on a second substrate, and

the placement of the coil of the adjustable tank circuit over the coil of the oscillator, wherein

the first and second substrates form part of a MCM.

7. An oscillator frequency adjustment apparatus comprising;

a first output and a second output,

one or more transformers where each transformer comprises at least two coils,

an oscillator circuit comprising;

at least one coil from the transformer,

at least one capacitor,

at least one regenerative circuit,

a means of coupling the coils, capacitors and regenerative circuits to form the oscillator circuit, wherein

the oscillator circuit is coupled to the first and second output, at least one tank circuit comprising;

the second coil of the transformer, and

at least one capacitor, wherein

the first coil from the oscillator circuit has an adjustable flux linkage with at least one coil from the tank circuit, wherein

the adjustable flux linkage is formed by a mechanical movement between the two coils, thereby

adjusting the frequency of operation of the apparatus.

8. The apparatus of claim 7 further comprising;

the fabrication of the first coil on a first substrate,

the fabrication of the second coil on a second substrate, and

the placement of the first coil over the second coil, wherein

the mechanical movement comprises;

a parallel displacement of the second substrate with respect to the first substrate.

9. The apparatus of claim 7 further comprising;

the fabrication of the first coil on a first substrate,

the fabrication of the second coil on a second substrate, and

the placement of the first coil over the second coil, wherein

the mechanical movement comprises;

a vertical displacement of the second substrate with respect to the first substrate.

10. The apparatus of claim 7 wherein;

the mechanical movement occurs within a MEMS.

11. The apparatus of claim 7 wherein;

the mechanical movement occurs within a MCM.

12. An oscillator frequency adjustment apparatus comprising;

an oscillator, comprising;

a least a first and second coil;

a first tank circuit comprising;

at least one coil, and

at least one capacitor,

a one additional tank circuit comprising;

at least one coil, and

at least one adjustable capacitor,

at least one coil from the first tank circuit has a flux linkage with at least one coil from the additional tank circuit, and

at least one capacitor from the additional tank circuit is adjustable, thereby adjusting the frequency of operation of the apparatus.

13. The apparatus of claim 12 wherein;

the one adjustable capacitor comprises;

a varactor.

14. The apparatus of claim 12 wherein;

the one adjustable capacitor comprises;

a digitally weighted capacitor.

15. The apparatus of claim 12 further comprising;

the fabrication of the oscillator on a first substrate,

the fabrication of the adjustable tank circuit on a second substrate, and

the placement of the coil of the adjustable tank circuit over the coil of the oscillator, wherein

the first and second substrates form part of a MCM.

16. An oscillator frequency adjustment apparatus comprising;

at least two tank circuits, wherein

each tank circuit comprising;

at least one coil, and

at least one capacitor, wherein

at least one coil from the first tank circuit has an adjustable flux linkage with at least one coil from the second tank circuit, wherein

the adjustable flux linkage is formed by a mechanical movement between the two coils, thereby

adjusting the frequency of operation of the apparatus.

17. The apparatus of claim 16 further comprising;

the fabrication of the first coil on a first substrate,

the fabrication of the second coil on a second substrate, and

the placement of the first coil over the second coil, wherein

the mechanical movement comprises;

a parallel displacement of the second substrate with respect to the first substrate.

18. The apparatus of claim 16 further comprising;

the fabrication of the first coil on a first substrate,

the fabrication of the second coil on a second substrate, and

the placement of the first coil over the second coil, wherein

the mechanical movement comprises;

a vertical displacement of the second substrate with respect to the first substrate.

19. A method of adjusting the capacitance in an array of oscillators comprising the steps of;

measuring the frequency of oscillation of an oscillator in the array,

comparing the frequency of oscillation of the oscillator against a reference,

adjusting a global coarse capacitor to all oscillators in the array,

(a) comparing the frequency of oscillation of the oscillator against a reference,

(b) adjusting a local fine capacitor in the oscillator,

(c) comparing the frequency of oscillation of the oscillator against a reference,

(d) latching the value of the fine adjust parameter for this oscillator when frequency is within specification,

(e) disabling the access to the oscillator,

(f) enabling the access to the next oscillator in the array, repeating steps (a) through (f), until all oscillators have been compared.

20. A method of adjusting the capacitance in an array of oscillators comprising the steps of;

(a) measuring the frequency of oscillation of an oscillator in the array,

(b) comparing the frequency of oscillation of the oscillator against a reference,

(c) adjusting a local coarse capacitor in the oscillator,

(d) comparing the frequency of oscillation of the oscillator against a reference,

(e) latching the value of the coarse adjust parameter for this oscillator when frequency is within specification,

(f) adjusting a local fine capacitor in the oscillator,

(g) comparing the frequency of oscillation of the oscillator against a reference,

(h) latching the value of the fine adjust parameter for this oscillator when frequency is within specification,

(i) disabling the access to the oscillator,

(j) enabling the access to the next oscillator in the array, repeating steps (a) through (j), until all oscillators have been compared.