Interference resistant local oscillator

• US 8,970,314 B2
• Filed: 04/27/2012
• Issued: 03/03/2015
• Est. Priority Date: 12/31/2008
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Goyal, Pankaj, Hull, Christopher
• Primary Examiner(s): Johnson, Ryan
• Application Number:
  US13/458,200
• Publication Number:
  US 20120214429A1
• Time in Patent Office: 1,040 Days
• Field of Search: 331/117.R, 331/117.FE, 331/167, 331/185, 331/186, 336/200, 336/232
• US Class Current: 331/117.FE
• CPC Class Codes: H01F 2017/0073 with a special conductive pattern, e.g. flat spiral
• CPC Class Codes: H03B 19/00 Generation of oscillations by non-regenerative frequency multiplication or division of a signal from a separate source transference of modulation from one carrier to another H03D7/00
• CPC Class Codes: H03B 2200/0088 Reduction of noise
• CPC Class Codes: H03B 2202/04 Reduction of undesired oscillations originated from outside noise or interferences, e.g. from parasitic couplings with circuit elements outside the oscillator
• CPC Class Codes: H03B 2202/044 the circuit element belonging to transmitter circuitry
• 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: H03B 5/1296 the feedback circuit comprising a transformer

Abstract

With some embodiments, a VCO (voltage controlled oscillator) operates at an integer multiple (N) above a desired transmission frequency. In accordance with one embodiment, a chip is provided with a VCO to generate a signal and a frequency dividing circuit to provide a reduced frequency version of the signal to a transmit mixer. The transmit mixer is followed by a power amplifier that is on the same die as the VCO. The power amplifier is to generate an OFDM output transmission.

Claims

1. A planar inductor comprising:

a first terminal and a second terminal;

a first metal loop coupled to the first and second terminals; and

a second metal loop, being symmetrical to the first metal loop, coupled to the first and second terminals,

wherein the first and second terminals are coupled to a voltage controlled oscillator (VCO) of a transmitter,

wherein the VCO is to receive a power supply from a regulator that has bandwidth which is higher than a modulation bandwidth of the transmitter; and

wherein the first and second metal loops are positioned such that interference is received along an axis dividing the first and second metal loops.

2. The planar inductor of claim 1 further comprises a shielding ring around the planar inductor.

3. The planar inductor of claim 1, wherein the first metal loop is positioned on one side of the first and second terminals, and wherein the second metal loop is positioned on another side of the first and second terminals.

4. The planar inductor of claim 1, wherein the first and second metal loops have identical shapes.

5. The planar inductor of claim 1 further comprises:

a third metal loop coupled to the first and second terminals; and

a fourth metal loop, being symmetrical to the third metal loop, coupled to the first and second terminals.

6. The planar inductor of claim 5, wherein the third and fourth metal loops have identical shapes.

7. The planar inductor of claim 1, wherein the first and second terminals are coupled to a varactor of the VCO.

8. The planar inductor of claim 1, wherein the VCO comprises a first transistor having a drain terminal coupled to the first terminal, and having a gate terminal coupled to the second terminal.

9. The planar inductor of claim 1, wherein the VCO comprises a second transistor having a drain terminal coupled to the second terminal, and having a gate terminal coupled to the first terminal.

10. The planar inductor of claim 1, wherein the VCO comprises a capacitor bank coupled to the first and second terminals.

11. The planar inductor of claim 1, wherein the VCO is powered by at least two regulators including the regulator.

12. The planar inductor of claim 1, wherein the VCO receives the power supply from a power delivery circuit including:

a pre-regulator to generate a regulated voltage supply;

a reference generator to receive the regulated voltage supply and to generate a reference voltage; and

the regulator to receive the reference voltage and to generate the power supply for the VCO.

13. The planar inductor of claim 12, wherein the first and second metal loops have tapered edges.

14. The planar inductor of claim 12, wherein the reference generator comprises a bandgap reference generator.

15. The planar inductor of claim 12, wherein the reference voltage is generated by a diode-connected transistor.

16. A system comprising:

a processor; and

a wireless interface communicatively coupled to the processor to communicatively link the processor to a wireless network, the wireless interface including a transmitter comprising;

a local oscillator having a voltage controlled oscillator (VCO) comprising a planar inductor including;

a first terminal and a second terminal;

a first metal loop coupled to the first and second terminals; and

a second metal loop, being symmetrical to the first loop, coupled to the first and second terminals,

wherein the VCO is to receive a power supply from a regulator that has bandwidth which is higher than a modulation bandwidth of the transmitter; and

wherein the first and second metal loops are positioned such that interference is received along an axis dividing the first and second metal loops.

17. The system of claim 16 further comprises a memory coupled to the processor.

18. The system of claim 16, wherein the wireless interface is coupled to an antenna.

19. The system of claim 16, wherein the planar inductor further comprises a shielding ring around the planar inductor.

20. The system of claim 16, wherein the first and second metal loops have identical shapes.

21. The system of claim 16 further comprises:

a third metal loop coupled to the first and second terminals; and

a fourth metal loop, being symmetrical to the third metal loop, coupled to the first and second terminals.

22. The system of claim 21, wherein the third and fourth metal loops have identical shapes.

23. The system of claim 16, wherein the first and second terminals are coupled to a varactor of the VCO.

24. The system of claim 16, wherein the VCO receives the power supply from a power delivery circuit including:

a pre-regulator to generate a regulated voltage supply;

a reference generator to receive the regulated voltage supply and to generate a reference voltage; and

the regulator to receive the reference voltage and to generate the power supply for the VCO.

25. The system of claim 24, wherein the first and second metal loops have tapered edges.

26. The system of claim 24, wherein the reference generator comprises a bandgap reference generator.

27. The system of claim 24, wherein the reference voltage is generated by a diode-connected transistor.

28. An apparatus comprising:

a regulator; and

a transmitter having an oscillator to receive a power supply from the regulator that has bandwidth which is higher than a modulation bandwidth of the transmitter, wherein the oscillator is an LC oscillator which comprises an inductor, wherein the inductor comprises;

a first terminal and a second terminal;

a first metal loop coupled to the first and second terminals; and

a second metal loop coupled to the first and second terminals, and

wherein the first and second metal loops are positioned such that interference is received along an axis dividing the first and second metal loops.

29. The apparatus of claim 28, wherein the oscillator comprises a capacitor coupled to the first and second terminals.