EP1163630A4 - Portable data device and method of switching between a power and data mode of operation - Google Patents
Portable data device and method of switching between a power and data mode of operationInfo
- Publication number
- EP1163630A4 EP1163630A4 EP98960458A EP98960458A EP1163630A4 EP 1163630 A4 EP1163630 A4 EP 1163630A4 EP 98960458 A EP98960458 A EP 98960458A EP 98960458 A EP98960458 A EP 98960458A EP 1163630 A4 EP1163630 A4 EP 1163630A4
- Authority
- EP
- European Patent Office
- Prior art keywords
- data
- power
- operably coupled
- terminal
- portable data
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
- G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
- G06K19/0701—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips at least one of the integrated circuit chips comprising an arrangement for power management
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
- G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
- G06K19/0723—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/0008—General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
Definitions
- the invention relates generally to portable data devices and a method for switching between two modes of operation thereof.
- Data transmission systems are known to include terminal devices (sometimes called readers or exciters) and portable data devices (sometimes called cards or smartcards). It is well understood that today's portable data devices include memory and processor devices require power from the terminal device. Once such a portable device (which may be contactless or contacted/contactless - sometimes referred to as combicards) enters into the excitation field of the terminal device, power and data can thereafter be transferred from the terminal device to the portable data device.
- portable data devices have been designed using two antenna structures; one for receiving power and a second for receiving/transmitting data. More recently, designs have focused on having a single antenna structure that is designed to receive power and data from the terminal device. (It should be noted that these antenna structures are commonly made of inductive coils, and such single antenna devices are commonly referred to as single coil cards.) Of course, reducing the number of antennas has the effect of introducing related circuit problems and design challenges.
- the coil in a single coil portable data device, serves as the power and signal reception element through which power and data signaling is delivered to the card.
- the power extraction and regulation circuitry regulates and delivers power from the coil while allowing the data signal to coexist on top of the regulated power.
- the regulated power is used by all circuitry on the portable data device.
- the receiver couples the data signal from the regulated power and transforms it to digital levels that can be further processed by the digital circuitry.
- the design of a receiver that optimizes power reception while still being able to accurately detect amplitude shift keying (ASK) modulated data can be rather complex.
- FIG. 1 shows a data transmission system that includes a terminal device and a portable data device, in accordance with the present invention
- FIG. 2 shows a more detailed view of the portable data device shown in FIG. 1 ;
- FIG. 3 shows a more detailed diagram of the shunt regulator circuit shown in FIG. 2;
- FIG. 4 shows a more detailed schematic diagram of a circuit that includes the mode selector shown in FIG. 2
- FIG. 5 shows a more detailed circuit diagram of the ASK receiver circuit shown in FIG. 2;
- FIG. 6 shows a more detailed schematic diagram of enhanced coupling circuit shown in FIG. 5;
- FIG. 7 shows a flow diagram depicting the mode selection operation, in accordance with the present invention.
- the present invention encompasses a portable data device that includes a single coil for receiving both power and data from a terminal device.
- the portable data device further includes a power rectifier and a shunt regulator circuit, which act in concert to extract power from signals emitted by the terminal device.
- An amplitude shift keyed (ASK) data receiver is also included on the card to receive transmitted data signals and produce demodulated data.
- a mode selector is employed for switching between the power extraction mode of operation and the data mode of operation.
- FIG. 1 shows a data transmission system 100 that includes a terminal device 101 and a portable data device 102, in accordance with the present invention.
- Terminal 101 includes a transmission structure 104, which consists of a single coil for transmitting both power and data. Power and data is transmitted using a signal that is partially modulated with data, typically with a modulation index of 10%. A partially modulated signal provides an uninterrupted power source that is required by the more sophisticated portable data devices, or smart cards, that use microprocessors.
- the card 102 includes a single coil 106 for receiving power signals and data signals from the terminal 101.
- a power extractor 108 is employed to extract power for use by the analog and digital circuitry employed by the card, as later described.
- a data receiver 110 is used to receive and demodulate the data signals transmitted from the terminal 101. Digital processor 110 is used to manipulate the demodulated data and perform various functions thereon.
- FIG. 2 shows a more detailed diagram of the portable data device 102 shown in FIG. 1.
- a shunt device 201 placed across the single coil 106, is controlled by a mode selector 203, as later described.
- the received signals are inputted to rectifier 205 to produce a rectified high voltage (Vdd) 207 and a rectified low voltage (Vss) 209.
- a shunt regulator circuit 211 which outputs a shunt control signal 213 as later described, is also employed by the card 102, in accordance with the invention.
- ASK amplitude shift keyed
- FIG. 3 shows a more detailed block diagram of the shunt regulator circuit 211 shown in FIG. 2.
- the shunt regulator circuit 211 consists of a reference voltage generator 302 and a differential comparison circuit 304.
- the reference voltage generator 302 generates a reference voltage for each of the corresponding nodes, Np and Nn.
- the voltage on node Np is referenced to Vdd and offset from Vdd to a lower potential value by a fixed amount.
- This offset voltage is set to one PMOS threshold voltage by using a PMOS device in a diode equivalent configuration (i.e., gate connected to the drain).
- the voltage on node Nn is referenced to Vss and offset from Vss to a higher value by a fixed amount.
- This offset voltage is set to one NMOS threshold voltage by using a NMOS device in a diode equivalent configuration (i.e., gate connected to the drain).
- a NMOS device in a diode equivalent configuration (i.e., gate connected to the drain).
- the potential between Vss and Vdd is below its regulated value
- the potential on Nn is higher than the potential on Np and the output of the comparison circuit is low.
- Vdd rises in response to receiving more power
- Np also rises by the same amount.
- Vss goes lower, in response to receiving more power, Nn also goes lower by the same amount. This phenomenon is used to effectively determine when the power is at an acceptable level, while still maintaining a level of receive sensitivity to accurately detect data, in accordance with the invention.
- the differential comparison signal 213 begins to rise.
- the output level of differential comparison signal 213 rises, it turns on the shunt device 201 , which in turn shunts a portion of the received power across the coil 106.
- the gain of the differential comparison circuit is kept low so that it does not overdrive the NMOS shunt device.
- the shunt device is of the 6
- NMOS type on a P-substrate which results in a more efficient structure without any additional semiconductor wells that can potentially cause a fatal condition commonly referred to as "latch-up.”
- the potential difference between Vdd and Vss (and correspondingly between Np and Nn) becomes larger.
- the larger potential between Np and Nn results in the comparison circuit 304 providing more drive to the shunt device 201 .
- the increased drive results in element 201 shunting most of the increased power across the coil, thus maintaining the rectified voltage within the operational range of the smart card chip.
- the reference voltage generator 302 develops a differential pair of voltage references (i.e., on nodes Np and Nn) to enhance the overall noise discrimination properties of the voltage regulator.
- these two reference voltages are generated using similar techniques so that noise coupled onto them has the same characteristics, and is therefor seen as so-called "common mode" by the differential comparison circuit 304.
- the differential comparison circuit 304 is designed to have a high common mode rejection capability and therefore does not react to any common mode signals.
- FIG. 4 shows a more detailed view of the mode selector 203, as well as the shunt device 201 , shown in FIG. 2.
- a time constant is derived from a resistive element 401 and the gate capacitance of the shunt device 201. This time constant determines the delay characteristics between the input of the mode selector 203 and its output.
- switch 403 When switch 403 is open, as shown, the time constant serves to delay any change in voltage from taking immediate effect at the gate of the shunt device 201.
- This mode is called the low dynamic mode or data receive mode, and accounts for why the simplified receiver configuration can effectively detect data on top of the received power signal, according to the invention, as next described.
- a data modulated power signal received from the terminal device 101 (shown in FIG. 1 ), results in a rectified DC power signal that has a differential data component.
- the differential data component consists of a signal that changes in opposing directions between nodes Vdd and Vss. If the received power signal increases in amplitude, in response to a modulated logic "1 " being transmitted, the differential data component on Vdd and Vss causes Vdd and Vss to diverge from each other. Conversely, when the received power signal is reduced in amplitude, in response to a modulated logic "0", Vdd and Vss converge toward each other.
- the resident processor e.g., microprocessor or microcontroller, not shown
- This higher impedance path selection results in a delay of the differential comparison signal 213 being applied to the shunt device 201.
- This delays the shunt device from responding and eliminating the amplitude change on Vdd and Vss, thereby allowing the data to exist on Vdd and Vss during and shortly after data transitions.
- the drive to the shunt device returns to the same potential as the differential comparison signal 213 (i.e., after the delay as determined by the time constant).
- resistor 405 resolves an initialization condition that occurs when the portable data device 102 first enters the excitation field from the terminal device 101.
- the condition occurs as the rectified voltage between Vdd and Vss begins to build, but is still below the operational level of the differential comparison circuit 304. Under this condition, no drive is being supplied from the differential comparison circuit 304, and thus, the only drive at the output of the mode selector 203 is through resistor 405.
- the drive through resistor 405 keeps shunt device 201 off until the rectified voltage is sufficient for the differential comparison circuit to drive the mode selector circuit.
- FIG. 5 shows a more detailed view of the receiver 215 shown in FIG. 2, in accordance with the invention.
- the ASK receiver consists of an enhanced coupling circuit 502, an intermediate amplification stage 504, a signal centering circuit 506 and a high-gain, noise tolerant amplifier 508.
- the enhanced signal coupling circuit 502 couples the differential data signal from Vdd and Vss onto nodes l and l N B
- the intermediate amplification stage 504, and the signal centering circuit 506, amplifies and re-centers the differential data signal about a common reference voltage.
- the final amplifier 508 is a high-gain stage capable of boosting the data signal to digital y levels.
- amplifier 508 provides a data-dependent hysteresis with respect to the re-centered differential input.
- the hysteresis characteristic provides some level of noise immunity and additionally serves to maintain a constant digital output level during long periods where there are no data transitions.
- FIG. 6 shows a more detailed view of the enhanced coupling circuit 502 shown in FIG. 5. As shown, capacitors C b couple the differential data
- DC coupling component 2 * (R2 - Rl * ( ⁇ Vdd + ⁇ Vss)
- FIG. 7 shows a data flow diagram 700 depicting operation of the mode selection method of the present invention.
- the power signal that is received by the card is rectified (704).
- the two reference voltages Vdd and Vss are generated (706) and compared (708) to produce a differential comparison signal (213 shown in FIG. 2).
- the rectified power signal is then regulated (710) to arrive at a stable operating voltage level (e.g., 3 volts).
- This mode of power regulation is referred to herein as the power extraction or high dynamic mode.
- This regulation step continues until it is determined (712) that the microprocessor is being powered by a stable operating voltage.
- the processor Upon stabilization, the processor then completes a majority of its digital operations in preparation for receiving data (713).
- the microprocessor then enters (714) the data mode, and is thereafter able to exchange data with the terminal device 101 shown in FIG. 1.
- the microprocessor sends a switch control signal 214 to the mode selector circuit 203 (both shown in FIG. 2) to open the switch 403 (shown in FIG. 4).
- the regulator enters (718) the data receive mode, referred to herein as the low dynamic mode.
- the circuits presented in FIG.s 1 through 6 offer a unique but simple solution to the problems of effective power regulation and noise isolation for a single coil portable data device.
- power regulation is achieved through a noise discriminating regulator that supports two modes of operation.
- a first mode which is highly dynamic
- the portable data device conducts the majority of its digital operations so that power fluctuations caused by turning on and off large digital functions (and the corresponding switching noise caused by these functions) is effectively eliminated.
- a second mode which has a slower response time
- both data and noise are allowed to coexist on Vdd and Vss.
- the portable data device curtails most of its digital operations while in this mode so that noise produced by turning on and off large digital functions (along with their associated switching noise) does not adversely affect the receiver.
- this shunt regulator provides two reference voltages having similar characteristics, so that noise is seen and rejected as common mode at the inputs to the comparator circuit.
- a unique coupling arrangement is provided that maximizes the amount of both AC and DC signal coupling.
Landscapes
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Artificial Intelligence (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Computer Networks & Wireless Communication (AREA)
- Near-Field Transmission Systems (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12392 | 1987-02-09 | ||
US1239298A | 1998-01-23 | 1998-01-23 | |
PCT/US1998/025134 WO1999038114A1 (en) | 1998-01-23 | 1998-11-24 | Portable data device and method of switching between a power and data mode of operation |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1163630A1 EP1163630A1 (en) | 2001-12-19 |
EP1163630A4 true EP1163630A4 (en) | 2002-07-31 |
Family
ID=21754758
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP98960458A Withdrawn EP1163630A4 (en) | 1998-01-23 | 1998-11-24 | Portable data device and method of switching between a power and data mode of operation |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP1163630A4 (en) |
WO (1) | WO1999038114A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3931500B2 (en) | 1999-09-22 | 2007-06-13 | 松下電器産業株式会社 | Non-contact IC card and data processing method thereof |
JP2003091391A (en) | 2001-09-17 | 2003-03-28 | Canon Inc | Peripheral device control method, program and computer for carrying out the same, peripheral device and computer system |
WO2019074690A1 (en) * | 2017-10-10 | 2019-04-18 | Tyco Fire & Security Gmbh | Systems and methods for operating tag |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2569194B2 (en) * | 1990-03-13 | 1997-01-08 | 三菱電機株式会社 | Microcomputer and non-contact IC card using the same |
JPH0528330A (en) * | 1991-07-24 | 1993-02-05 | Mitsubishi Electric Corp | Non-contact type portable carrier and its initializing method |
JPH087059A (en) * | 1994-06-21 | 1996-01-12 | Sony Chem Corp | Noncontact information card |
JPH0962816A (en) * | 1994-10-06 | 1997-03-07 | Mitsubishi Electric Corp | Non-contact ic card and non-contact ic card system including the same |
-
1998
- 1998-11-24 WO PCT/US1998/025134 patent/WO1999038114A1/en not_active Application Discontinuation
- 1998-11-24 EP EP98960458A patent/EP1163630A4/en not_active Withdrawn
Non-Patent Citations (2)
Title |
---|
No further relevant documents disclosed * |
See also references of WO9938114A1 * |
Also Published As
Publication number | Publication date |
---|---|
EP1163630A1 (en) | 2001-12-19 |
AU719445B2 (en) | 2000-05-11 |
AU1604399A (en) | 1999-08-09 |
WO1999038114A1 (en) | 1999-07-29 |
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Legal Events
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
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18W | Application withdrawn |
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