Download AsyncRFID : Fully Asynchronous Contactless Systems

2006
AsyncRFID : Fully Asynchronous Contactless Systems,
Providing High Data Rates,
Low Power and Dynamic Adaptation
Edith Beigné – Damien Caucheteux
Marc Renaudin – Elisabeth Crochon
Async’06
[email protected]
Async’06 Symposium – Grenoble – E. Beigné
1
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
2
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
3
2006
Introduction to contactless passive devices
Reader Module
Energy / Data
Passive Tag
Application
front-end
front-end
control &
demodulation
Specific Data Base
V CCA
gnd
Data
•
Contactless passive devices :
– Consists of at least a reader and one or more tag
– Passive tags : do not implement batteries
•
Downlink communication : Reader transmits data and energy to tag
•
Uplink communication : Tag sends data back to the reader
•
Short range applications :
– Radio Frequency Identification (RFID) systems
– Financial & Secured systems
– Biometrical systems
Async’06 Symposium – Grenoble – E. Beigné
4
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
5
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
– Contactless system constraints
– Motivations for asynchronous logic on tag
– Towards a fully asynchronous contactless system
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
6
Contactless system constraints
2006
•
Energy constraints :
– Energy received on tag is limited (power emission standards/antenna parameters)
¨ Dynamic power consumption has to be minimized
– Supply Voltage is unstable (process drifts/distance/modulation symbols)
¨ On-tag electronics must be robust to supply voltage variations
•
Data transmission constraints :
– Standards define maximum data rates
– High data rates impose strict conditions of use
– Compromise is made between data rates, distances and power
¨ Lack of flexibility for actual contactless systems
•
Digital synchronous circuits on-tag :
– Synchronous circuits are sensitive to supply voltage
¨ Strong voltage regulation is needed on tag
– Global clock is a source of noise (problems for integrated MEMs or RF devices)
¨ Noise source reduction
Async’06 Symposium – Grenoble – E. Beigné
7
Motivations for asynchronous logic on tag
2006
•
Handshake protocol makes operators data driven
¨ Only active where and when needed
F Reduction of global power consumption for digital blocks
•
Activations distributed over time
¨ smoothing the consumed current profile
F Reduction of dynamic power consumption
•
Delay insensitivity
¨ Robust to voltage variations
F Automatic performances regulation
Reduction of energy management constraints for tag analog front-end
Improvement of on tag digital circuitry characteristics
Async’06 Symposium – Grenoble – E. Beigné
8
2006
Towards a fully asynchronous contactless system
•
Current research works focus on asynchronous digital block design
preserving a classical standard ISO 14443 synchronous protocol
Passive Tag
Energy/Data/CLK
front-end
Specific Data Base
Data/Request
Reader
Module
Data
CLK
V CCA
OP1
OP2
Ack
ASYNCHRONOUS
DIGITAL BLOCK
gnd
2
CLK
Async’06 Symposium – Grenoble – E. Beigné
9
2006
Towards a fully asynchronous contactless system
•
Current research works focus on asynchronous digital block design
preserving a classical standard ISO 14443 synchronous protocol
•
We propose to push the asynchronous logic paradigm to system level
Passive Tag
Data / Request
front-end
Specific Data Base
Data/Request
Reader
Module
Ack
2
CLK
V CCA
OP1
OP2
Ack
ASYNCHRONOUS
DIGITAL BLOCK
gnd
2
CLK
Async’06 Symposium – Grenoble – E. Beigné
10
2006
Towards a fully asynchronous contactless system
•
Current research works focus on asynchronous digital block design
preserving a classical standard ISO 14443 synchronous protocol
•
We propose to push the asynchronous logic paradigm to system level
Passive Tag
Ack
front-end
Specific Data Base
Data/Request
Reader
Module
Data / Request
2
CLK
V CCA
OP1
OP2
Ack
ASYNCHRONOUS
DIGITAL BLOCK
gnd
2
CLK
¨ Flexible contactless system :
– Allows dynamic adaptation of the tag to environment
– Provides a range of data rates
– Offers data rate / consumption / distance trade-offs
Async’06 Symposium – Grenoble – E. Beigné
11
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
12
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
– Main objectives
– Asynchronous event based communication
– Implementation
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
13
2006
A fully asynchronous contactless system : Main Objectives
Main Objectives :
• Take full advantage of asynchronous circuits properties at system level
– Dynamic adaptation to environment
– Dynamic compromise between device performances
•
•
•
Easy integration of an asynchronous digital circuit on tag
High performances tags
Insensitivity to supply voltage variations
How :
• Extension of the Asynchronous paradigm to the inductive link
– Use of a specific synchronization for each data to replace a data flow transmission
clock
– Use of asynchronous codes (data value + data synchronization)
– No predetermined time between two successive data
•
Design of a self-adaptive contactless interface
– Detection of each incoming data
– Dynamic compromise between performances
Async’06 Symposium – Grenoble – E. Beigné
14
2006
Asynchronous event-based communication
•
Time independent communication scheme
¨ No global clock but a specific synchronization
•
Use of asynchronous codes
¨ Carrying data values and data synchronization
•
No pre-determined time between two
successive data
•
No synchronization with a carrier
•
Self adaptive Front-End to data rate
¨ Tracking and detection of data events on coil
Classic synchronous NRZ code
Problem of an asynchronous communication
TRZ
1
0
1
1
0
0
1
0
Asynchronous flow using a TRZ code
Async’06 Symposium – Grenoble – E. Beigné
15
2006
Asynchronous event-based communication : implementation
π
•
Principle
– Asynchronous code is carrying data values and
data synchronization
– Requires a specific code adapted to high performance
simulation
•
3π '1' 2 '1' π
4
4
'0' '0'
'1'
'1'
'0'
'0'
π
0
'0'
'0'
'1'
'1'
'0' '0'
π
3π
−
−
π
'
1
'
4 '1' −
4
2
Downlink communication (reader to tag)
– Phase modulation (PSK) on a 13.56 MHz frequency
– Cyclic Asynchronous Code (CAC) with 8 phase states
¨ Lowers amplitude modulation caused by phase shifts
¨ Improves power transmission
¨ Allows any communication data rates up to 1.0 Mbps
• Uplink communication (tag to reader)
– Phase modulation (PSK) on a 848 kHz sub-carrier
– Cyclic Asynchronous Code (CAC) with 4 phase states
¨ Improves tag to reader communication performances
Downlink communication illustration
Async’06 Symposium – Grenoble – E. Beigné
16
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
17
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
– Tag architecture
– Asynchronous phase jump detector
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
18
2006
•
A self adaptive to data rate front-end : tag architecture
Usual functions
Power on
Reset
Demod. 1
VCCA
C
Bridge
Retromodulation unit & control
Coil voltage limiter
External reference extraction, …
Retromodulation
Retromod.
Control
PLL Regulation
Demod. 2
C
&
Ext-Ref
Extraction
Limiter
Phase Lock Loop
Pad Control and Test
–
–
–
–
Current
Generator
Bridge
gnd
•
Asynchronous transmission demodulator
– Charge pump PLL at 13.56 MHz
– Voltage Controlled Oscillator (VCO)
– Phase and Frequency Detector (PFD)
VOSC
R1
C2
VCC
Ref- Ext
¨detects phase events and activates the
data
APJD
Ref- Int
Up
PFD
C1
CP
down
Vcont
VCO
charge pump
¨ Compares the external (coil) and internal (VCO) reference
– Asynchronous Phase jump detector (APJD)
¨ Receives PFD outputs and demodulates phase shifts
Async’06 Symposium – Grenoble – E. Beigné
19
2006
•
Asynchronous Phase Jump Detector (APJD)
Filtering
¨ dissociates data events from phase noise
•
Signature detection
¨ links phase shifts with data received
•
Detection of event envelop
¨ Compares phases
•
Output interface
¨ Fits asynchronous logic codes
Up/Down
No time reference:
data is detected whatever is the
data rate
delay line τ
Up/Down
FilerIni
Up/Down
FilterOuti
&
D Q
13.56 MHz
reference
Up/Down
Marki
Async’06 Symposium – Grenoble – E. Beigné
20
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
21
2006
Implementation and layout
•
•
ST 0.13 µm CMOS technology, 1.2 V
1.37 mm² including test pads
1045 µm2
1308 µm2
AsyncRFID test chip layout
AsyncRFID test chip micrograph
Async’06 Symposium – Grenoble – E. Beigné
22
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
23
2006
Results
Reader to tag distance
0 cm
6 cm
Received supply voltage
1.06 V
870 mV
Current consumption
98.3 µA
84.8 µA
Power consumption
104 µW
73.8 µW
VCO supply voltage
783 mV
751 mV
Maximum data rate
1.02 Mbps
952 kbps
Ext-Ref
Int-Ref
‘1’
A demodulation test result
@ 1.02Mbps – 1cm
Async’06 Symposium – Grenoble – E. Beigné
24
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
25
2006
Comparison
ISO 14443
standard
Leti-TIMA
AsyncRFID
Leti
EPSIS3
Montréal
University
2000
2004
2005
2003
Architecture
*
PLL
PLL+Σ∆
PLL
Modulation
2-ASK
8-CAC PSK
4-ASK
BPSK
*
from 0 to 6 cm
0 to 5 cm
few mm
106 kbps
any from 0 to
1.02 Mbps
1.7 Mbps
1.12 Mbps
*
< 100 µA
150 µA
400 µA
Project
Date
Communication distances @ 0.6W
Downlink data rate
Global power consumption
•
•
•
•
High data rate
Low power consumption
High communication distance range
Dynamical performance adaptation to environment
Async’06 Symposium – Grenoble – E. Beigné
26
2006
•
Introduction to contactless passive devices
•
Specifications of a new class of devices
•
A fully asynchronous contactless system
•
A self adaptive to data rate front-end
•
Implementation & Layout
•
Results
•
Comparison
•
Conclusion
Async’06 Symposium – Grenoble – E. Beigné
27
2006
•
Conclusion
A fully asynchronous and self-adaptive to data rate passive
contactless device
–
–
–
–
Low power consumption
High data rates up to 1.02 Mbps
Low sensitivity to supply voltage variations
Long communication range
•
Target power or performances depending on application or
environment : Multi-application tags
•
Can take full advantage of an asynchronous digital block
– Tag is fully data driven
– Handshake protocol at system level
– Adaptation according to environmental conditions
Async’06 Symposium – Grenoble – E. Beigné
28