CA2312974A1 - Active transponder switchable into passive transponder - Google Patents
Active transponder switchable into passive transponder Download PDFInfo
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- CA2312974A1 CA2312974A1 CA002312974A CA2312974A CA2312974A1 CA 2312974 A1 CA2312974 A1 CA 2312974A1 CA 002312974 A CA002312974 A CA 002312974A CA 2312974 A CA2312974 A CA 2312974A CA 2312974 A1 CA2312974 A1 CA 2312974A1
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- transponder
- power supply
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Classifications
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- 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
- G06K19/0702—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 the arrangement including a battery
- G06K19/0705—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 the arrangement including a battery the battery being connected to a power saving arrangement
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- 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
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- 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
Abstract
The invention concerns an active transponder (10) comprising an antenna (3), processing means (5) for receiving and supplying the antenna with identification data to be transmitted, powering means (7) for supplying a first signal (V1), storage means (12) for storing electric power and supplying a second signal (V2), and switching means (16) for connecting the processing means to the storage means or to the powering means. Said transponder also comprises first and second means (14, 15) for comparing the first and second signals with a predetermined threshold, and the switching means produces said connection on the basis of said comparisons. Such a transponder is useful for determining whether the voltage supplied by the powering means are sufficient for providing electric power to the different transponder components, in particular for ensuring the desired functions.
Description
Case 1617 ACTIVE TRANSPONDER ABLE TO BE SWITCHED
INTO A PASSIVE TRANSPONDER
The present invention concerns the field of active transponders and, more particularly, active transponders able to be switched into passive transponders.
Conventionally, there exist a large number of portable devices for identifying an unknown object at a distance. Typically, data is transferred, in the form of radio-electric signals, between a fixed base station acting as a transceiver, and a portable device which is usually made using a transponder.
Two types of transponders conventionally need to be distinguished.
A " passive " transponder is one which converts a radio-electric signal originating from a base station, into an electric voltage which then supplies the electric power necessary for the transponder to operate. For this purpose, a passive transponder includes an antenna arranged to be able to receive and transmit radio-electric signals containing data, a storage capacitor connected to the antenna, to be able to store the electric power received by the antenna, and an integrated circuit connected to the antenna and to the storage capacitor, to be able to process the data received by the antenna, and to supply the latter with other data to be transmitted in the form of radio-electric signals. It is to be noted that, in a transponder of this type, the storage capacitor supplies the integrated circuit with electric power.
An " active ° transponder is one such as described hereinafter. Figure 1 shows a transponder of this type designated by the reference 1. This transponder includes an antenna 3 arranged to be able to receive and transmit radio-electric signals containing data, an integrated circuit 5 connected to antenna 3, to be able to process data received by antenna 3, and to supply the latter with other data to be transmitted in the form of radio-electric signals. Active transponder 1 further includes an internal electric power source , which is commonly formed by a lithium battery, designated in Figure 1 by the reference 7. It is to be noted that, in a transponder of this type, battery 7 .
supplies the various components with electric power.
Active transponders are used to transmit data over large distances. For example, they are commonly used in a key for opening a vehicle door by remote control, without there being any material contact between the door and the key, or even any action on the key by a user.
Active transponders of the aforementioned type which include a capacitor arranged to be able to store the electric power received by the antenna also exist.
British Patent No. GB 2,292,866 discloses an active transponder of this type which further includes switching means arranged so that, when the voltage supplied by the storage capacitor is less than the voltage supplied by the power supply means, the latter supplies the various components of the transponder with power and, when the voltage supplied by the storage capacitor is greater than the voltage supplied by the power supply means, the storage capacitor supplies the components with power.
One drawback of these active transponders lies in the fact that they operate normally, as long as the battery supplies sufficient electric voltage to supply all the transponder components with power. Thus, in the aforecited example in which an active transponder is incorporated in a key, let us assume that the battery no longer supplies a sufficient voltage level to assure that the transponder operates properly. In this case, the transponder no longer allows the door opening instruction to be provided, which is generally inconvenient for the user.
One object of the present invention is to provide an active transponder which overcomes the drawbacks of conventional active transponders, in particular relative to its operation when the battery supplies insufficient electric voltage to supply all the transponder components with power.
Another object of the present invention is to provide an active transponder answering the conventional criteria in the semi-conductor industry as to complexity and cost.
These objects, in addition to others, are achieved by the active transponder according to claim 1.
One advantage of the transponder switching means according to the present invention is that they allow the transponder to determine whether the voltage value supplied by the power supply means is sufficient to assure the electric power supply of the various transponder components, in particular to perform the desired elementary functions.
Another advantage of the transponder switching means according to the present invention lies in the fact that the arrangement thereof allows a parasitic vertical bipolar type transistor to be prevented from being made conductive, when the field effect transistors of the switching means are blocked.
Another advantage of the transponder switching means according to the present invention lies in the fact that the arrangement thereof provides a low voltage drop across its input terminal and its output terminal, which allows the electric power supply for the processing means to be realised at a voltage which is substantially equal to that provided by the power supply means.
One advantage of the transponder according to the present invention lies in the fact that it is formed of components usually made in the semiconductor industry, in particular by known CMOS type manufacturing steps.
INTO A PASSIVE TRANSPONDER
The present invention concerns the field of active transponders and, more particularly, active transponders able to be switched into passive transponders.
Conventionally, there exist a large number of portable devices for identifying an unknown object at a distance. Typically, data is transferred, in the form of radio-electric signals, between a fixed base station acting as a transceiver, and a portable device which is usually made using a transponder.
Two types of transponders conventionally need to be distinguished.
A " passive " transponder is one which converts a radio-electric signal originating from a base station, into an electric voltage which then supplies the electric power necessary for the transponder to operate. For this purpose, a passive transponder includes an antenna arranged to be able to receive and transmit radio-electric signals containing data, a storage capacitor connected to the antenna, to be able to store the electric power received by the antenna, and an integrated circuit connected to the antenna and to the storage capacitor, to be able to process the data received by the antenna, and to supply the latter with other data to be transmitted in the form of radio-electric signals. It is to be noted that, in a transponder of this type, the storage capacitor supplies the integrated circuit with electric power.
An " active ° transponder is one such as described hereinafter. Figure 1 shows a transponder of this type designated by the reference 1. This transponder includes an antenna 3 arranged to be able to receive and transmit radio-electric signals containing data, an integrated circuit 5 connected to antenna 3, to be able to process data received by antenna 3, and to supply the latter with other data to be transmitted in the form of radio-electric signals. Active transponder 1 further includes an internal electric power source , which is commonly formed by a lithium battery, designated in Figure 1 by the reference 7. It is to be noted that, in a transponder of this type, battery 7 .
supplies the various components with electric power.
Active transponders are used to transmit data over large distances. For example, they are commonly used in a key for opening a vehicle door by remote control, without there being any material contact between the door and the key, or even any action on the key by a user.
Active transponders of the aforementioned type which include a capacitor arranged to be able to store the electric power received by the antenna also exist.
British Patent No. GB 2,292,866 discloses an active transponder of this type which further includes switching means arranged so that, when the voltage supplied by the storage capacitor is less than the voltage supplied by the power supply means, the latter supplies the various components of the transponder with power and, when the voltage supplied by the storage capacitor is greater than the voltage supplied by the power supply means, the storage capacitor supplies the components with power.
One drawback of these active transponders lies in the fact that they operate normally, as long as the battery supplies sufficient electric voltage to supply all the transponder components with power. Thus, in the aforecited example in which an active transponder is incorporated in a key, let us assume that the battery no longer supplies a sufficient voltage level to assure that the transponder operates properly. In this case, the transponder no longer allows the door opening instruction to be provided, which is generally inconvenient for the user.
One object of the present invention is to provide an active transponder which overcomes the drawbacks of conventional active transponders, in particular relative to its operation when the battery supplies insufficient electric voltage to supply all the transponder components with power.
Another object of the present invention is to provide an active transponder answering the conventional criteria in the semi-conductor industry as to complexity and cost.
These objects, in addition to others, are achieved by the active transponder according to claim 1.
One advantage of the transponder switching means according to the present invention is that they allow the transponder to determine whether the voltage value supplied by the power supply means is sufficient to assure the electric power supply of the various transponder components, in particular to perform the desired elementary functions.
Another advantage of the transponder switching means according to the present invention lies in the fact that the arrangement thereof allows a parasitic vertical bipolar type transistor to be prevented from being made conductive, when the field effect transistors of the switching means are blocked.
Another advantage of the transponder switching means according to the present invention lies in the fact that the arrangement thereof provides a low voltage drop across its input terminal and its output terminal, which allows the electric power supply for the processing means to be realised at a voltage which is substantially equal to that provided by the power supply means.
One advantage of the transponder according to the present invention lies in the fact that it is formed of components usually made in the semiconductor industry, in particular by known CMOS type manufacturing steps.
These objects, features and advantages, in addition to others, will appear more clearly upon reading the detailed description of a preferred embodiment of the invention, given solely by way of example, in relation to the annexed drawings, in which:
- Figure 1 which has already been cited, shows a conventional active transponder;
- Figure 2 shows an active transponder according to the present invention;
- Figure 3 shows a preferred embodiment of the transponder switching means of Figure 2; and - Figure 4 shows the timing diagrams of five voltages present in the transponder of Figure 2.
Figure 2 shows an active transponder 10 according to the present invention.
It is to be noted that the transponder shown in Figure 2 is close to transponder 1 shown in Figure 1. Thus for the sake of simplicity, the components shown in Figure 2 and designated by the same references as those shown in Figure 1, are substantially identical to those designated in Figure 1.
As Figure 2 shows, active transponder 10 includes an antenna 3, processing means 5, and power supply means 7.
Antenna 3 is arranged to be able to receive and transmit data to and from an external device (for example a conventional base station), via a radio-electric signal 4.
Antenna 3 includes two connection terminals 30 and 31 via which the data received or the data to be transmitted, are provided, in the form of an electric signal.
Antenna 3 is preferably made forming a coil, as is known.
Processing means 5 are arranged to be able to process the received data and to provide the data to be transmitted. For this purpose, processing means 5 include two connection terminals 50 and 51 connected respectively to terminals 30 and 31 of antenna 3. Further, processing means 5 include an earth terminal 52 connected to transponder 10's earth, and a power supply terminal 53 for receiving supply voltage Vdd, as will be described hereinafter. Processing means 5 also include four additional connection terminals designated 54 to 57.
Processing means 5 are preferably made by forming a convention logic block and a conventional interface arranged between the block and antenna 3, such an interface being described for example in the aforecited British Patent No. GB
2,292,866 . Essentially, this interface includes a circuit able to provide power from a signal 4 received by antenna 3. For this purpose, a circuit of this type includes a bridge of four diodes for converting the alternating voltage of signal 4 into a d.c.
voltage.
- Figure 1 which has already been cited, shows a conventional active transponder;
- Figure 2 shows an active transponder according to the present invention;
- Figure 3 shows a preferred embodiment of the transponder switching means of Figure 2; and - Figure 4 shows the timing diagrams of five voltages present in the transponder of Figure 2.
Figure 2 shows an active transponder 10 according to the present invention.
It is to be noted that the transponder shown in Figure 2 is close to transponder 1 shown in Figure 1. Thus for the sake of simplicity, the components shown in Figure 2 and designated by the same references as those shown in Figure 1, are substantially identical to those designated in Figure 1.
As Figure 2 shows, active transponder 10 includes an antenna 3, processing means 5, and power supply means 7.
Antenna 3 is arranged to be able to receive and transmit data to and from an external device (for example a conventional base station), via a radio-electric signal 4.
Antenna 3 includes two connection terminals 30 and 31 via which the data received or the data to be transmitted, are provided, in the form of an electric signal.
Antenna 3 is preferably made forming a coil, as is known.
Processing means 5 are arranged to be able to process the received data and to provide the data to be transmitted. For this purpose, processing means 5 include two connection terminals 50 and 51 connected respectively to terminals 30 and 31 of antenna 3. Further, processing means 5 include an earth terminal 52 connected to transponder 10's earth, and a power supply terminal 53 for receiving supply voltage Vdd, as will be described hereinafter. Processing means 5 also include four additional connection terminals designated 54 to 57.
Processing means 5 are preferably made by forming a convention logic block and a conventional interface arranged between the block and antenna 3, such an interface being described for example in the aforecited British Patent No. GB
2,292,866 . Essentially, this interface includes a circuit able to provide power from a signal 4 received by antenna 3. For this purpose, a circuit of this type includes a bridge of four diodes for converting the alternating voltage of signal 4 into a d.c.
voltage.
Power supply means 7 are arranged to be able to provide an electric voltage V1 sufficient to electrically supply all the components of transponder 10. For this purpose, power supply means 7 include a supply terminal 70 for supplying voltage V1, and an earth terminal 71 connected to transponder 10's earth.
Power supply means 7 are preferably made using a conventional lithium battery or a conventional accumulator.
Transponder 10 further includes storage means 12, two comparison means 14 and 15, and switching means 16.
Storage means 12 are arranged to be able to store electric power, and to supply an electric voltage V2. For this purpose, storage means 12 include a terminal 120 connected to terminal 57 of processing means 5 and, more particularly, to said interface of processing means 5, so as to receive the power received by antenna 3, i.e. said d.c. voltage derived from signal 4. Storage means 12 further include an earth terminal 121 connected to transponder 10's earth.
Storage means 12 are preferably made by forming a conventional capacitor connected across terminals 120 and 121, so that the voltage present across these terminals forms d.c. voltage V2.
Comparison means 14 are arranged to be able to compare electric voltage V1 to a predetermined voltage threshold Vth. For this purpose, comparison means include a first input terminal 140 connected to memory means 18, to receive threshold Vth, and a second input terminal 141 connected to terminal 70 of power supply means 7, for receiving voltage V1. Comparison means 14 also include an output terminal 142 connected to terminal 54 of processing means 5 to provide such means with an electric signal V3 containing the result of the comparison between voltage V1 and threshold Vth.
It is to be noted that threshold value Vth is selected and stored to answer predetermined criteria for the proper operation of transponder 10, i.e. to determine whether the voltage value supplied by the battery is sufficient to assure the electric power supply for transponder 10, necessary to perform the desired functions, such as providing a remote vehicle door opening instruction signal.
Comparison means 14 are preferably made using an operational amplifier, as is known.
Like comparison means 14, comparison means 15 are arranged to be able to compare electric voltage V2 to voltage threshold Vth. For this purpose, comparison means 15 include a first input terminal 150 connected to storage means 18, to receive threshold Vth, and a second input terminal 151 connected to terminal 120 of storage means 12, to receive voltage V2. Comparison means 15 also include an output terminal 152 connected to terminal 56 of processing means 5, to supply said means with an electric signal V4 containing the result of the comparison between voltage V2 and threshold Vth.
Comparison means 15 are preferably made using an operational amplifier, as is known.
Switching means 16 are arranged to be able to connect processing means 5 to storage means 12 or to power supply means 7, under the control of processing means 5, and as a function of the results of the comparisons of voltages V1 and V2 to threshold Vth. For this purpose, switching means 16 include a first input terminal 160 connected to terminal 70 of power supply means 7, to receive voltage V1, a second input terminal 161 connected to terminal 120 of storage means 12, to receive voltage V2, at least one control terminal 162 connected to terminal 55 of processing means 5, to receive from said means an electric switching instruction signal, and an output terminal 163 connected to terminal 53, to provide processing means 5 with voltage Vdd necessary for its electric power supply.
It is to be noted that processing means 5 are programmed so as to be able to provide, via terminal 55, the switching instruction to means 16, in response to electric signals V3 and V4 received by the respective terminals 54 and 56.
A preferred embodiment of switching means 16 of transponder 10 will be described hereinafter.
Figure 3 shows an electric diagram of switching means 16.
Switching means 16 are formed of four transistors, Ta, Tb, Tc and Td which, in the example shown in Figure 3, are P channel field effect transistors.
The references Sa, Da and Ga respectively designate the source terminal, drain terminal and gate terminal of transistor Ta. The source, drain and gate terminals of transistors Tb, Tc and Td will be designated in a similar manner.
Transistors Ta to Td are connected in series, in the following manner.
Terminals Ga to Gd are connected respectively to four control terminals designated 162a to 162d, so that each of the transistors can received, from processing means 5, said switching command, so as to be conductive or blocked. Terminals Sa and Sd are connected respectively to terminals 160 and 161, to receive respectively voltages V1 and V2. Terminals Sb and Sc are connected to terminal 163 of switching means 16, and terminals Da and Dc are respectively connected to terminals Db and Dd.
Those skilled in the art will note that the voltage drop across terminals 163 and 160, and terminals 163 and 161 is of the order of 200 mV, in the event that P
type channel transistors Ta to Td are formed in four respective slightly doped N
type wells, these wells being formed in a slightly doped P type silicon substrate.
Power supply means 7 are preferably made using a conventional lithium battery or a conventional accumulator.
Transponder 10 further includes storage means 12, two comparison means 14 and 15, and switching means 16.
Storage means 12 are arranged to be able to store electric power, and to supply an electric voltage V2. For this purpose, storage means 12 include a terminal 120 connected to terminal 57 of processing means 5 and, more particularly, to said interface of processing means 5, so as to receive the power received by antenna 3, i.e. said d.c. voltage derived from signal 4. Storage means 12 further include an earth terminal 121 connected to transponder 10's earth.
Storage means 12 are preferably made by forming a conventional capacitor connected across terminals 120 and 121, so that the voltage present across these terminals forms d.c. voltage V2.
Comparison means 14 are arranged to be able to compare electric voltage V1 to a predetermined voltage threshold Vth. For this purpose, comparison means include a first input terminal 140 connected to memory means 18, to receive threshold Vth, and a second input terminal 141 connected to terminal 70 of power supply means 7, for receiving voltage V1. Comparison means 14 also include an output terminal 142 connected to terminal 54 of processing means 5 to provide such means with an electric signal V3 containing the result of the comparison between voltage V1 and threshold Vth.
It is to be noted that threshold value Vth is selected and stored to answer predetermined criteria for the proper operation of transponder 10, i.e. to determine whether the voltage value supplied by the battery is sufficient to assure the electric power supply for transponder 10, necessary to perform the desired functions, such as providing a remote vehicle door opening instruction signal.
Comparison means 14 are preferably made using an operational amplifier, as is known.
Like comparison means 14, comparison means 15 are arranged to be able to compare electric voltage V2 to voltage threshold Vth. For this purpose, comparison means 15 include a first input terminal 150 connected to storage means 18, to receive threshold Vth, and a second input terminal 151 connected to terminal 120 of storage means 12, to receive voltage V2. Comparison means 15 also include an output terminal 152 connected to terminal 56 of processing means 5, to supply said means with an electric signal V4 containing the result of the comparison between voltage V2 and threshold Vth.
Comparison means 15 are preferably made using an operational amplifier, as is known.
Switching means 16 are arranged to be able to connect processing means 5 to storage means 12 or to power supply means 7, under the control of processing means 5, and as a function of the results of the comparisons of voltages V1 and V2 to threshold Vth. For this purpose, switching means 16 include a first input terminal 160 connected to terminal 70 of power supply means 7, to receive voltage V1, a second input terminal 161 connected to terminal 120 of storage means 12, to receive voltage V2, at least one control terminal 162 connected to terminal 55 of processing means 5, to receive from said means an electric switching instruction signal, and an output terminal 163 connected to terminal 53, to provide processing means 5 with voltage Vdd necessary for its electric power supply.
It is to be noted that processing means 5 are programmed so as to be able to provide, via terminal 55, the switching instruction to means 16, in response to electric signals V3 and V4 received by the respective terminals 54 and 56.
A preferred embodiment of switching means 16 of transponder 10 will be described hereinafter.
Figure 3 shows an electric diagram of switching means 16.
Switching means 16 are formed of four transistors, Ta, Tb, Tc and Td which, in the example shown in Figure 3, are P channel field effect transistors.
The references Sa, Da and Ga respectively designate the source terminal, drain terminal and gate terminal of transistor Ta. The source, drain and gate terminals of transistors Tb, Tc and Td will be designated in a similar manner.
Transistors Ta to Td are connected in series, in the following manner.
Terminals Ga to Gd are connected respectively to four control terminals designated 162a to 162d, so that each of the transistors can received, from processing means 5, said switching command, so as to be conductive or blocked. Terminals Sa and Sd are connected respectively to terminals 160 and 161, to receive respectively voltages V1 and V2. Terminals Sb and Sc are connected to terminal 163 of switching means 16, and terminals Da and Dc are respectively connected to terminals Db and Dd.
Those skilled in the art will note that the voltage drop across terminals 163 and 160, and terminals 163 and 161 is of the order of 200 mV, in the event that P
type channel transistors Ta to Td are formed in four respective slightly doped N
type wells, these wells being formed in a slightly doped P type silicon substrate.
Preferably, all the components of transponder 10 are made forming an integrated structure by known CMOS type manufacturing steps. Typically, in their aforementioned preferred respective embodiment, processing means 5, storage means 12, comparison means 14 and 15 and switching means 16 are made in a monolithic manner in a single semiconductor substrate. By way of variant, in addition to these components, antenna 3 can also be made in a monolithic manner.
Those skilled in the art will note that the arrangement of the switching means far transponder 10 is advantageous, since it prevents a parasitic vertical bipolar type transistor being made conductive when the field effect transistors of these means are blocked. Indeed, in the case described in relation to Figure 3, these transistors are of P channel type, drain terminal Da is connected to drain terminal Db and drain terminal Dc is connected to drain terminal Dd. It will be recalled that a parasitic vertical bipolar type transistor associated with a P channel type field effect transistor becomes conductive only if the drain voltage of the transistor is greater than the source voltage of the order of 0.6 V. The transistor can only become conductive in this way when transistors Ta and Tb, respectively Tc and Td are blocked, since the drain terminals of the transistors are in a high impedance state.
The operation of the transponder according to the present invention will now be described with reference to Figures 2 and 3 described above.
Figure 4 shows five timing diagrams 41 to 45 illustrating the temporal evolution of voltages V1, V2, V3, V4 and Vdd, respectively.
Let us consider the case in which power supply means 7 supply a voltage V1 which is both substantially equal to the desired supply level V0, and higher than threshold Vth, as illustrated by timing diagram 41 between instants t0 and t1.
In this case, comparison means 14 supplies signal V3 at a level " 1 " for example, between instants t0 and t1. As a result, processing means 5 commands switching means 16 to make transistors Ta and Tb conductive, and to block transistors Tc and Td.
Thus, between instants t0 and t1, voltage Vdd is substantially equal to voltage V1.
Thus connected, transponder 10 operates as an active transponder as described above. In other words, antenna 3 transmits radio-electric signals containing data intended to be received by a base station. These signals are supplied by processing means 5 which receives a d.c. supply voltage Vdd equal to voltage V1, for as long as the latter is higher than threshold Vth.
It is to be noted that, between instants t0 and t1, storage means 12 receives power from antenna 3, via processing means 5, so that voltage V2 increases until it reaches threshold Vth at an instant t2. Voltage V2 then continues to increase until it reaches level V0.
Those skilled in the art will note that the arrangement of the switching means far transponder 10 is advantageous, since it prevents a parasitic vertical bipolar type transistor being made conductive when the field effect transistors of these means are blocked. Indeed, in the case described in relation to Figure 3, these transistors are of P channel type, drain terminal Da is connected to drain terminal Db and drain terminal Dc is connected to drain terminal Dd. It will be recalled that a parasitic vertical bipolar type transistor associated with a P channel type field effect transistor becomes conductive only if the drain voltage of the transistor is greater than the source voltage of the order of 0.6 V. The transistor can only become conductive in this way when transistors Ta and Tb, respectively Tc and Td are blocked, since the drain terminals of the transistors are in a high impedance state.
The operation of the transponder according to the present invention will now be described with reference to Figures 2 and 3 described above.
Figure 4 shows five timing diagrams 41 to 45 illustrating the temporal evolution of voltages V1, V2, V3, V4 and Vdd, respectively.
Let us consider the case in which power supply means 7 supply a voltage V1 which is both substantially equal to the desired supply level V0, and higher than threshold Vth, as illustrated by timing diagram 41 between instants t0 and t1.
In this case, comparison means 14 supplies signal V3 at a level " 1 " for example, between instants t0 and t1. As a result, processing means 5 commands switching means 16 to make transistors Ta and Tb conductive, and to block transistors Tc and Td.
Thus, between instants t0 and t1, voltage Vdd is substantially equal to voltage V1.
Thus connected, transponder 10 operates as an active transponder as described above. In other words, antenna 3 transmits radio-electric signals containing data intended to be received by a base station. These signals are supplied by processing means 5 which receives a d.c. supply voltage Vdd equal to voltage V1, for as long as the latter is higher than threshold Vth.
It is to be noted that, between instants t0 and t1, storage means 12 receives power from antenna 3, via processing means 5, so that voltage V2 increases until it reaches threshold Vth at an instant t2. Voltage V2 then continues to increase until it reaches level V0.
Let us consider now the case in which power supply means 7 supplies voltage V1 at a value which is less than threshold Vth, as illustrated by timing diagram 41 from instant t1. In this case, voltage V1 is no longer sufficient to assure the electric power supply for transponder 10 necessary to perform the desired functions, which means that, from instant t1, voltage V1 is less than threshold Vth. Consequently, at instant t1, voltage V3 becomes equal to a level " 0 " and, at the same instant, since voltage V2 is higher than threshold Vth, voltage V4 becomes equal to level " 1 ", so that, processing means 5 commands switching means 16 to block transistors Ta and Tb, and to make transistors Tc and Td conductive. Thus, from instant t1, voltage Vdd is substantially equal to voltage V2.
Thus connected, transponder 10 thus operates like a passive transponder as described above. In other words, a base station transmits radio-electric signals containing data and electric power. When transponder 10 is placed in close proximity to the base station, antenna 3 receives said data which are then processed by processing means 5, as well as the electric power which continues to be stored in storage means 12, so that voltage V2 is substantially equal to level V0. In response, processing means 5 supplies antenna 3 with other data which are intended to be received by the base station. These signals are provided by processing means 5 which receives a supply voltage Vdd equal to voltage V2, this voltage originating from the electric power stored in storage means 12.
Those skilled in the art will note that the arrangement of the transponder switching means according to the present invention is advantageous since it allows the transponder to determine whether the voltage value supplied by the battery is sufficient to assure the electric powering thereof, in particular to perform the desired elementary functions, for example supplying a remote vehicle door opening instruction signal.
It goes without saying for those skilled in the art that the above detailed description can undergo various modifications without departing from the scope of the present invention. By way of variant, the transponder switching means according to the present invention can be made by forming N type channel field effect transistors in four respective slightly doped P type wells, these wells being formed in a slightly doped N type silicon substrate.
Thus connected, transponder 10 thus operates like a passive transponder as described above. In other words, a base station transmits radio-electric signals containing data and electric power. When transponder 10 is placed in close proximity to the base station, antenna 3 receives said data which are then processed by processing means 5, as well as the electric power which continues to be stored in storage means 12, so that voltage V2 is substantially equal to level V0. In response, processing means 5 supplies antenna 3 with other data which are intended to be received by the base station. These signals are provided by processing means 5 which receives a supply voltage Vdd equal to voltage V2, this voltage originating from the electric power stored in storage means 12.
Those skilled in the art will note that the arrangement of the transponder switching means according to the present invention is advantageous since it allows the transponder to determine whether the voltage value supplied by the battery is sufficient to assure the electric powering thereof, in particular to perform the desired elementary functions, for example supplying a remote vehicle door opening instruction signal.
It goes without saying for those skilled in the art that the above detailed description can undergo various modifications without departing from the scope of the present invention. By way of variant, the transponder switching means according to the present invention can be made by forming N type channel field effect transistors in four respective slightly doped P type wells, these wells being formed in a slightly doped N type silicon substrate.
Claims (8)
1. Active transponder (10) including:
- an antenna (3) arranged to be able to receive and transmit at least one radio-electric signal containing data;
- processing means (5) connected to the antenna, and arranged to be able to receive and supply to the antenna identification data to be transmitted in the form of radio-electric signals;
- power supply means (7) arranged to be able to supply a first electric supply signal (V1) for all the transponder components;
- storage means (12) arranged to be able to store electric power and to provide a second electric power signal (V2); and - switching means (16) connected to comparison means, to the processing means, to the storage means, and to the power supply means, and arranged to be able to connect the processing means to the storage means or to the power supply means, said transponder being characterised in that it includes further first and second means (14, 15) for comparing respectively the first and second power supply signals to a predetermined threshold (Vth) provided by supply means (18), and in that the switching means are arranged so that, when the first signal is greater than the predetermined threshold, the processing unit is connected to the power supply means to assure the electric power supply for the transponder components and, when the first signal is less than the predetermined threshold and the second signal is greater than the predetermined threshold, the processing unit is connected to the storage means to assure the electric power supply for the transponder components.
- an antenna (3) arranged to be able to receive and transmit at least one radio-electric signal containing data;
- processing means (5) connected to the antenna, and arranged to be able to receive and supply to the antenna identification data to be transmitted in the form of radio-electric signals;
- power supply means (7) arranged to be able to supply a first electric supply signal (V1) for all the transponder components;
- storage means (12) arranged to be able to store electric power and to provide a second electric power signal (V2); and - switching means (16) connected to comparison means, to the processing means, to the storage means, and to the power supply means, and arranged to be able to connect the processing means to the storage means or to the power supply means, said transponder being characterised in that it includes further first and second means (14, 15) for comparing respectively the first and second power supply signals to a predetermined threshold (Vth) provided by supply means (18), and in that the switching means are arranged so that, when the first signal is greater than the predetermined threshold, the processing unit is connected to the power supply means to assure the electric power supply for the transponder components and, when the first signal is less than the predetermined threshold and the second signal is greater than the predetermined threshold, the processing unit is connected to the storage means to assure the electric power supply for the transponder components.
2. Active transponder (10) according to claim 1, characterised in that the processing means (5), the storage means (12), the first and second comparison means (14, 15) and the switching means (16) are made in a monolithic manner in a' single semiconductor substrate.
3. Active transponder (10) according to claim 2, characterised in that the antenna (3) is made in a monolithic manner in said substrate.
4. Active transponder (10) according to claim 2 or 3, characterised in that the switching means (16) are formed in a slightly doped P type silicon substrate, in which are formed first, second, third and fourth lightly doped N type wells, in each of which is formed respectively a first, second, third or fourth P type channel field effect transistor (Ta, Tb, Tc, Td).
5. Active transponder (10) according to claim 4, characterised in that the first, second, third and fourth transistors (Ta, Tb, Tc, Td) are connected in series, in that the gate terminals (Ga, Gb, Gc, Gd) of the first, second, third and fourth transistors are connected to the processing means (5), in that the source terminals (Sa, Sd) of the first and fourth transistors (Ta, Td) are connected respectively to the power supply means (7) and to the storage means (12), and in that the drain terminals (Db, Dc) of the second and third transistors (Tb, Tc) are connected to the processing means (5) to act as electric power supply terminals for the processing means (5).
6. Active transponder (10) according to claim 2, characterised in that the switching means (16) are formed in a lightly doped N type silicon substrate, in which are formed first, second, third and fourth slightly doped P type wells, in each of which is formed a first, second, third or fourth N type channel field effect transistor.
7. Active transponder (10) according to claim 6, characterised in that the first, second, third and fourth transistors are connected in series, in that the gate terminals of the first, second, third and fourth transistors are connected to the processing means, in that the drain terminals of the first and fourth transistors are respectively connected to the power supply means and to the storage means, and in that the source terminals of the second and third transistors are connected to the processing means to act as electric power supply terminals for the processing'means.
8. Portable device including an active transponder according to any of the preceding claims.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP97122712A EP0926623A1 (en) | 1997-12-23 | 1997-12-23 | Active transponder switchable to passive transponder |
| EP97122712.9 | 1997-12-23 | ||
| CH295597 | 1997-12-23 | ||
| CH2955/97 | 1997-12-23 | ||
| PCT/EP1998/006470 WO1999034325A1 (en) | 1997-12-23 | 1998-10-12 | Active transponder switchable into passive transponder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2312974A1 true CA2312974A1 (en) | 1999-07-08 |
Family
ID=25691821
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002312974A Abandoned CA2312974A1 (en) | 1997-12-23 | 1998-10-12 | Active transponder switchable into passive transponder |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP1040447B1 (en) |
| JP (1) | JP2002500400A (en) |
| AT (1) | ATE212141T1 (en) |
| CA (1) | CA2312974A1 (en) |
| DE (1) | DE69803227T2 (en) |
| WO (1) | WO1999034325A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2807586B1 (en) * | 2000-04-05 | 2002-07-05 | St Microelectronics Sa | LOAD MODULATION DEVICE IN AN INTEGRATED TELE-POWERED CIRCUIT |
| ATE316270T1 (en) * | 2001-08-08 | 2006-02-15 | Koninkl Philips Electronics Nv | DATA CARRIER HAVING AN ACTIVE SIGNAL PROCESSING CIRCUIT AND A PASSIVE SIGNAL PROCESSING CIRCUIT |
| US6700491B2 (en) * | 2002-06-14 | 2004-03-02 | Sensormatic Electronics Corporation | Radio frequency identification tag with thin-film battery for antenna |
| JP4579233B2 (en) * | 2003-04-29 | 2010-11-10 | エヌエックスピー ビー ヴィ | Circuit for contactless devices with active and passive transmission modes |
| DE10325909A1 (en) | 2003-06-05 | 2005-01-05 | Deutsche Post Ag | Method and device for securing objects |
| WO2007012031A2 (en) | 2005-07-19 | 2007-01-25 | Precision Dynamics Corporation | Semi-active rfid tag and related processes |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8701541A (en) * | 1987-07-01 | 1989-02-01 | Nedap Nv | IDENTIFICATION SYSTEM FOR LIVESTOCK FARMING. |
| JPH01123269U (en) * | 1988-02-16 | 1989-08-22 | ||
| WO1992008148A1 (en) * | 1990-11-06 | 1992-05-14 | Westinghouse Electric Corporation | Dual mode electronic identification system |
| JPH0869513A (en) * | 1994-08-30 | 1996-03-12 | Mitsubishi Denki Semiconductor Software Kk | Noncontact ic card |
| US6130602A (en) * | 1996-05-13 | 2000-10-10 | Micron Technology, Inc. | Radio frequency data communications device |
-
1998
- 1998-10-12 WO PCT/EP1998/006470 patent/WO1999034325A1/en active IP Right Grant
- 1998-10-12 JP JP2000526899A patent/JP2002500400A/en active Pending
- 1998-10-12 DE DE69803227T patent/DE69803227T2/en not_active Expired - Fee Related
- 1998-10-12 EP EP98955439A patent/EP1040447B1/en not_active Expired - Lifetime
- 1998-10-12 AT AT98955439T patent/ATE212141T1/en not_active IP Right Cessation
- 1998-10-12 CA CA002312974A patent/CA2312974A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| WO1999034325A1 (en) | 1999-07-08 |
| JP2002500400A (en) | 2002-01-08 |
| EP1040447A1 (en) | 2000-10-04 |
| EP1040447B1 (en) | 2002-01-16 |
| DE69803227D1 (en) | 2002-02-21 |
| ATE212141T1 (en) | 2002-02-15 |
| DE69803227T2 (en) | 2002-09-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |