RFID using an hybrid on-chip-off-chip transformer

• US 8,064,864 B2
• Filed: 04/30/2009
• Issued: 11/22/2011
• Est. Priority Date: 09/28/2006
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Rofougaran, Ahmadreza (Reza)
• Primary Examiner(s): LE, NHAN T
• Application Number:
  US12/433,100
• Publication Number:
  US 20090224886A1
• Time in Patent Office: 936 Days
• Field of Search: 455/280, 455/292, 455/323, 455/333, 455/334, 340/10.1
• US Class Current: 455/292
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies
• CPC Class Codes: H01F 19/08 Transformers having magnetic bias, e.g. for handling pulses
• 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 23/48 Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• 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: H01L 2924/3011 Impedance
• CPC Class Codes: H04B 5/263 Multiple coils at either side
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A radio frequency identification (RFID) system includes an RFID reader and an RFID tag. The RFID reader is coupled to transmit first electromagnetic signal via an off-chip winding section of a hybrid on-chip-off-chip transformer. The RFID tag is coupled to receive the first electromagnetic signal via an on-chip winding section of the hybrid on-chip-off-chip transformer, wherein the on-chip winding section derives a second electromagnetic signal from the first electromagnetic signal when the on-chip winding section is within a proximal coupling distance of the off-chip winding section.

Claims

1. A radio frequency identification (RFID) system comprises:

an RFID reader coupled to transmit first electromagnetic signal via an off-chip winding section of a hybrid on-chip-off-chip transformer; and

an RFID tag coupled to receive the first electromagnetic signal via an on-chip winding section of the hybrid on-chip-off-chip transformer, wherein the on-chip winding section derives a second electromagnetic signal from the first electromagnetic signal when the on-chip winding section is within a proximal coupling distance of the off-chip winding section, wherein the on-chip winding section includes a first plurality of multiple turn coils on at least one layer of a multiple layer integrated circuit (IC) die, in which the proximal coupling distance provides a substantially perpendicular, with respect to the at least one layer of the multiple layer IC die, electromagnetic field of the first electromagnetic signal to the first plurality of multiple turn coils, and wherein the on-chip winding section also includes a second plurality of multiple turn coils on at least one other layer of the multiple layer IC die, in which the proximal coupling distance provides a substantially perpendicular, with respect to the at least one other layer of the multiple layer IC die, electromagnetic field of the first electromagnetic signal to the second plurality of multiple turn coils, and wherein the first and second pluralities of multiple turn coils provide the second electromagnetic signal.

2. The RFID system of claim 1, wherein the off-chip winding section includes a ferrite core having an air gap and a first winding wrapped around the ferrite core, in which the air gap substantially provides the first electromagnetic signal to the on-chip winding section.

3. The RFID system of claim 2, wherein the off-chip winding section further includes an alignment guide such that, when the off-chip winding section is within the proximal coupling distance of the on-chip winding section, the air gap provides the substantially perpendicular electromagnetic field of the first electromagnetic signal.

4. The RFID system of claim 2 further comprises:

an electromagnetic field conversion circuit coupled to the on-chip winding section, in which when the off-chip winding section is within the proximal coupling distance of the on-chip winding section, the electromagnetic field conversion circuit changes orientation of an electromagnetic field provided by the air gap to be substantially perpendicular to layers of the IC die.

5. The RFID system of claim 1, wherein the off-chip winding section includes an air core and a first winding wrapped around the air core, in which flux from the air core substantially provides the first electromagnetic signal to the on-chip winding section.