LOW POWER LO DISTRIBUTION USING A FREQUENCY-MULTIPLYING SUBHARMONICALLY INJECTION-LOCKED OSCILLATOR

• US 20110003571A1
• Filed: 07/01/2009
• Published: 01/06/2011
• Est. Priority Date: 07/01/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Park, Dongmin, Savoj, Jafar
• Granted Patent: US 9,374,100 B2
• Time in Patent Office: Days
• US Class Current: 455/258
• CPC Class Codes: H03B 19/14 by means of a semiconductor device
• CPC Class Codes: H03B 2200/007 Generation of oscillations based on harmonic frequencies, e.g. overtone oscillators
• CPC Class Codes: H03B 2200/0074 Locking of an oscillator by injecting an input signal directly into the oscillator
• CPC Class Codes: H03B 2200/0078 generating or using signals in quadrature
• CPC Class Codes: H03B 2200/0082 Lowering the supply voltage and saving power
• 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 5/1215 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: H03L 7/24 using a reference signal directly applied to the generator

Abstract

A local oscillator communicates a signal of relatively low frequency across an integrated circuit to the location of a mixer. Near the mixer, a frequency-multiplying SubHarmonically Injection-Locked Oscillator (SHILO) receives the signal and generates therefrom a higher frequency signal. If the SHILO outputs I and Q quadrature signals, then the I and Q signals drive the mixer. If the SHILO does not generate quadrature signals, then a quadrature generating circuit receives the SHILO output signal and generates therefrom I and Q signals that drive the mixer. In one advantageous aspect, the frequency of the signal communicated over distance from the local oscillator to the SHILO is lower than the frequency of the I and Q signals that drive the mixer locally. Reducing the frequency of the signal communicated over distance can reduce power consumption of the LO signal distribution system by more than fifty percent as compared to conventional systems.

Claims

1. An integrated circuit comprising:

a local oscillator that outputs a first signal of a first frequency;

a SubHarmonically Injection-Locked Oscillator (SHILO) that receives the first signal and generates therefrom a second signal of a second frequency, wherein the second frequency is an integer multiple of the first frequency; and

a quadrature signal generator that receives the second signal and generates therefrom an in-phase (I) signal of a third frequency and a quadrature (Q) signal of the third frequency.

2. The integrated circuit of claim 1, wherein the first signal is communicated a distance of more than one millimeter across the integrated circuit from the local oscillator to the SHILO.

3. The integrated circuit of claim 1, wherein the local oscillator is disposed more than one millimeter away from the SHILO, and wherein the third frequency is greater than the first frequency.

4. The integrated circuit of claim 1, further comprising:

a mixer that receives the I signal and the Q signal.

5. The integrated circuit of claim 1, wherein the third frequency is half the second frequency.

6. The integrated circuit of claim 1, wherein the first signal received by the SHILO is taken from the group consisting of:

a single-ended signal, and a differential signal.

7. The integrated circuit of claim 1, wherein the first signal is a first periodic signal and the first frequency is the fundamental of the first periodic signal, wherein the second signal is a second periodic signal and the second frequency is the fundamental of the second periodic signal, and wherein the I and Q signals are third periodic signals and the third frequency is the fundamental of the third periodic signals.

8. The integrated circuit of claim 1, wherein the SHILO comprises:

a pulse generator that receives the first signal and generates therefrom a pulse signal; and

an oscillator having a frequency lock range that includes the second frequency but does not include the first frequency, wherein the oscillator receives the pulse signal, and wherein the oscillator outputs the second signal of the second frequency.

9. The integrated circuit of claim 1, wherein the SHILO includes an oscillator, wherein the oscillator includes an LC tank circuit, wherein the LC tank circuit includes an inductor and a capacitor.

10. The integrated circuit of claim 1, wherein the SHILO includes a ring oscillator.

11. The integrated circuit of claim 8, wherein the pulse signal is a signal that includes a plurality of identical pulses, wherein each of the identical pulses has a pulse width, and wherein the pulse width is determined by a propagation delay of a circuit element in the pulse generator.

12. A method comprising:

(a) communicating a first signal a distance of more than one millimeter across an integrated circuit to a SubHarmonically Injection-Locked Oscillator (SHILO), wherein the first signal is a periodic signal of a first frequency;

(b) receiving the first signal onto the SHILO and using the SHILO to generate a second signal of a second frequency, wherein the second frequency is an integer multiple of the first frequency; and

(c) receiving the second signal onto a quadrature signal generator circuit and using the quadrature signal generator circuit to generate an in-phase (I) signal of a third frequency and a quadrature (Q) signal of the third frequency, wherein the third frequency is greater than the first frequency.

13. The method of claim 12, wherein the first signal is communicated in (a) from a local oscillator to the SHILO.

14. The method of claim 13, further comprising:

(d) supplying the I signal and the Q signal to a mixer.

15. The method of claim 12, wherein the generating of the second signal in (b) comprises:

receiving the first signal and generating a pulse signal therefrom; and

supplying the pulse signal to an oscillator such that the oscillator oscillates at the second frequency and outputs the second signal.

16. The method of claim 12, wherein the SHILO includes an oscillator, wherein the oscillator includes an LC tank circuit, and wherein the LC tank circuit includes an inductor and a capacitor.

17. The method of claim 12, wherein the SHILO includes a ring oscillator.

18. An integrated circuit comprising:

a local oscillator that outputs a periodic signal of a first frequency;

a SubHarmonically Injection-Locked Oscillator (SHILO) that is disposed more than one millimeter away from the local oscillator, wherein the SHILO receives the periodic signal and generates therefrom an in-phase (I) differential signal and a quadrature (Q) differential signal, wherein the I and Q differential signals are of a second frequency that is greater than the first frequency; and

a mixer that receives the I and Q differential signals from the SHILO.

19. The integrated circuit of claim 18, wherein the SHILO is disposed substantially less than one millimeter away from the mixer, and wherein the SHILO includes a Quadrature Voltage-Controlled Oscillator (QVCO).

20. A method comprising:

(a) communicating a periodic signal of a first frequency a distance of more than one millimeter across an integrated circuit from a local oscillator to a SubHarmonically Injection-Locked Oscillator (SHILO);

(b) receiving the periodic signal onto the SHILO and using the SHILO to generate an in-phase (I) differential signal and a quadrature (Q) differential signal, wherein the I and Q differential signals are of a second frequency that is greater than the first frequency; and

(c) supplying the I and Q differential signals to a mixer.

21. The method of claim 20, wherein the SHILO is disposed substantially less than one millimeter away from the mixer, wherein the SHILO includes a Quadrature Voltage-Controlled Oscillator (QVCO).

22. An integrated circuit comprising:

a mixer; and

means for communicating a periodic signal from a local oscillator a distance of more than one millimeter, for using the periodic signal to generate an in-phase (I) signal of a second frequency and to generate a quadrature (Q) signal of the second frequency, wherein the periodic signal is of a first frequency, wherein the second frequency is greater than the first frequency and is an integer multiple of the first frequency, and for supplying the I and Q signals to the mixer.

23. The integrated circuit of claim 22, wherein the means communicates the periodic signal across a conductor from the local oscillator to a location adjacent the mixer, and wherein the means is for generating the I signal and the Q signal at the location.

24. The integrated circuit of claim 22, wherein the means comprises a SubHarmonically Injection-Locked Oscillator (SHILO) and a quadrature signal generator circuit.

25. The integrated circuit of claim 22, wherein the means comprises a SubHarmonically Injection-Locked Oscillator (SHILO) that outputs the I and Q signals.