Tunable guard ring for improved circuit isolation

• US 9,312,927 B2
• Filed: 11/11/2013
• Issued: 04/12/2016
• Est. Priority Date: 11/11/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Bhagat, Maulin Pareshbhai, Myers, Thomas Andrew, Nan, Lan, Jin, Zhang
• Primary Examiner(s): Lee, Benny
• Assistant Examiner(s): Dieujuste, Albens
• Application Number:
  US14/076,298
• Publication Number:
  US 20150130552A1
• Time in Patent Office: 883 Days
• Field of Search: 333/12, 333/177, 333/179, 333/180, 333/24.R, 333/175, 455/41.1
• US Class Current: 1/1
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H01L 2223/6661 for passive devices
• CPC Class Codes: H01L 2223/6688 Mixed frequency adaptations, i.e. for operation at different frequencies
• CPC Class Codes: H01L 23/5223 Capacitor integral with wiring layers
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: H01L 23/645 Inductive arrangements H01L23/647, H01L23/66 take precedence
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• CPC Class Codes: H01L 28/10 Inductors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H04B 5/24 Inductive coupling

Abstract

A tunable guard ring for improved circuit isolation is disclosed. In an exemplary embodiment, an apparatus includes a closed loop guard ring formed on an integrated circuit and magnetically coupled by a selected coupling factor to a first inductor formed on the integrated circuit. The apparatus also includes a tunable capacitor forming a portion of the closed loop guard ring and configured to reduce magnetic field coupling from the first inductor to a second inductor.

Claims

1. An apparatus comprising:

a closed loop guard ring formed on an integrated circuit and magnetically coupled by a selected coupling factor to a first inductor formed on the integrated circuit; and

a tunable capacitor forming a portion of the closed loop guard ring and configured to reduce magnetic field coupling from the first inductor to a second inductor.

2. The apparatus of claim 1, wherein the closed loop guard ring surrounds the first inductor on the integrated circuit.

3. The apparatus of claim 1, wherein the tunable capacitor is tuned in response to a control signal.

4. The apparatus of claim 1, wherein the first inductor surrounds the closed loop guard ring on the integrated circuit.

5. The apparatus of claim 4, further comprising one or more additional closed loop guard rings coupled to the first inductor on the integrated circuit.

6. The apparatus of claim 5, further comprising at least one additional closed loop guard ring surrounding the first inductor on the integrated circuit.

7. The apparatus of claim 1, wherein the first inductor forms a part of a first circuit that operates at a first frequency and the second inductor forms a part of a second circuit that operates at a second frequency.

8. The apparatus of claim 7, wherein the first frequency is configured to be lower than the second frequency.

9. The apparatus of claim 8, wherein the closed loop guard ring is further configured to reduce magnetic field coupling of a harmonic of the first frequency to the second inductor.

10. The apparatus of claim 1, wherein the closed loop guard ring comprises inductive elements which include the closed loop guard ring, resistive elements, and capacitive elements which include the tunable capacitor, said inductive, resistive and capacitive elements are connected in series and the series connected elements are tuned to reduce magnetic field coupling from the first inductor to the second inductor within a selected frequency range.

11. An apparatus comprising:

means for magnetically coupling a closed loop guard ring to a first inductance by a selected coupling factor, the closed loop guard ring and the first inductance formed on an integrated circuit; and

means for providing a tunable capacitance forming a portion of the closed loop guard ring and configured to reduce magnetic field coupling from the first inductance to a second inductance.

12. The apparatus of claim 11, wherein the closed loop guard ring surrounds the first inductance on the integrated circuit.

13. The apparatus of claim 11, wherein the means for providing a tunable capacitance is being configured to be tuned in response to a control signal.

14. The apparatus of claim 11, wherein the first inductance is configured to surround the closed loop guard ring on the integrated circuit.

15. The apparatus of claim 14, further comprising one or more additional closed loop guard rings coupled to the first inductance on the integrated circuit.

16. The apparatus of claim 15, further comprising at least one additional closed loop guard ring surrounding the first inductance on the integrated circuit.

17. The apparatus of claim 11, wherein a part of a first circuit, which is formed by the first inductance, operates at a first frequency and a part of a second circuit, which is formed by the second inductance, operates at a second frequency.

18. The apparatus of claim 17, wherein the first frequency is configured to be lower than the second frequency.

19. The apparatus of claim 18, wherein the closed loop guard ring is further configured to reduce magnetic field coupling of a harmonic of the first frequency to the second inductance.

20. The apparatus of claim 11, wherein the closed loop guard ring comprises inductive elements which include the closed loop guard ring, resistive elements, and capacitive elements which include the tunable capacitor, said inductive, resistive and capacitive elements are connected in series and the series connected elements are tuned to reduce magnetic field coupling within a selected frequency range.