WO2010142597A1

WO2010142597A1 - Low-power portable electronic device

Info

Publication number: WO2010142597A1
Application number: PCT/EP2010/057775
Authority: WO
Inventors: Michel Thill
Original assignee: Gemalto SA
Current assignee: Thales DIS France SA
Priority date: 2009-06-12
Filing date: 2010-06-03
Publication date: 2010-12-16
Anticipated expiration: 2011-12-12
Also published as: EP2267649A1

Abstract

The invention relates to the area of portable electronic devices 1 using a contactless communication protocol where it is important to conserve the electric power capacity of the power supply means 4. The invention provides that such a device 1 comprises detecting means 6 to detect a characteristic movement by the wearer of the device to trigger the starting of the device after the said characteristic movement is detected.

Description

LOW-POWER PORTABLE ELECTRONIC DEVICE

The invention relates to electronic devices that chiefly communicate with the outside through contactless communication protocols. Such devices, which include contactless cards, smart cards and electronic card holders, communicate with a terminal or a reader through radioelectric signals or using technology such as Bluetooth etc.

The invention has many applications in cash transactions, electronic purses, transactions relating to healthcare, gaming and access control.

In particular, it concerns devices comprising their own electric power supply means that provide the power required for operation and for enabling them to use such communication. The power supply means generally comprise one or more batteries. Some batteries are not designed to be rechargeable, in order to reduce their cost and size. Other batteries are rechargeable but recharging can be difficult or awkward to implement and lead to extra cost. Whatever the technology selected, it is crucial to conserve the capacity of the battery to provide sufficient power to allow the nominal operating of the communicating device.

To make up for that drawback, a first solution consists in giving such a device a button, such as an on/off button, to connect or disconnect the microcontroller to or from the said power supply means.

That technique may be expensive and unreliable. That is because the mechanical components generally used can rapidly show signs of wear and tear. The technique further requires action that is not easy for a bearer or user of the device, particularly if a small button is used. Such a button may further be accidentally manoeuvred without the knowledge of the said user in certain storage conditions or in certain immediate environments of the device, which may lead to accidental and involuntary starting. The battery may thus be discharged rapidly when the microcontroller of the device is switched on unintentionally. Another solution consists in giving such a portable electronic device the means to start the microcontroller of the said device automatically when the device enters a field, such as a radiofrequency field. The field thus "wakes" the device, particularly its microcontroller, to allow it to complete a transaction. At the end of the transaction, the microcontroller switches off and no longer draws power from the power supply means of the portable device. However, unintentional and frequent waking of the microcontroller in the presence of a field when the bearer of the said device does not necessarily wish to carry out a transaction largely reduces the life of the battery of the device .

This invention is aimed at doing away with the drawbacks listed above by allowing the device to detect a characteristic movement made deliberately by the user. When the said movement is detected, that starts or wakes the microcontroller. The capacity of the electric power means is thus conserved and the life of the battery of the communicating device is maximised.

To that end, the invention relates to a portable electronic device comprising: - a microcontroller, communication means that work with the said microcontroller to transmit and/or receive radioelectric signals to/from a terminal in accordance with a contactless communication protocol, power supply means to provide power to allow the operating of the microcontroller. To conserve the capacity of the said power supply means, the device comprises a movement detector to detect a characteristic voluntary movement made by the bearer of the device. Further, the said detector supplies an electric signal to start the microcontroller and supply it with electric power from the power supply means. In a first variant of embodiment of a device according to the invention, the detector can supply the said electric signal to the microcontroller to switch it on.

In a second variant, the detector may supply the said electric signal to switching means that apply to the microcontroller the power available from the power supply means to switch on the said microcontroller.

To further increase the life of the battery, the invention provides that the detector may require a insignificant quantity of power or no power at all with regard to the power required for the working of the microcontroller.

For example, the detector of a device according to the invention may comprise passive electronic components.

As a variant, the said detector may comprise an accelerometer or even a light sensor as an alternative or in combination .

In the preferred mode of embodiment of such a device, the invention provides that the microcontroller can interrupt its operating and control the suspension of the electric power supply following a predetermined period of time of inactivity.

Further, also in order to improve battery life, the microcontroller in the invention can interrupt its working and control the suspension of the electric power supply if there is no radioelectric field, which absence is detected by transmitting and/or receiving means.

Other characteristics and benefits will become clearer in the description below and the figures accompanying it, where:

- figures 1 - 3 respectively present a communicating device according to techniques belonging to the prior art; - figures 4 -6 respectively present a mode of embodiment of a communicating device according to the invention. Figure 1 shows a known communicating device comprising a microcontroller 2 that is capable of implementing an application program. Thus, device 1 may receive commands or orders from the outside, which are interpreted by the microcontroller 2, which carries out functions in return. To implement the said functions, the microcontroller may use program and/or data memories internal to the microcontroller or working with it. To receive orders from the outside or even transmit results or requests in return, the microcontroller 2 works 11 with communication means 3 for transmitting and/or receiving, means represented in relation with figure 1, in the form of a coil or antenna.

In order to implement communication protocols, for instance using Bluetooth technology, it is necessary for the device 1 to comprise power supply means 4. The said means supply 12 to the microcontroller 2 the power that is required and sufficient for operating. The exchange 30 between the device 1 and the outside represented in relation with figure 1 in the form of a terminal 20 takes place through a field, for example of the radiofrequency type. Such a device 1 is for instance a contactless card or a smart card with an antenna. It may also take the form of a card holder for a conventional smart card, one with no contactless communication means, which changes the said card into a communicating device. The structure, size, form and functions of the device 1 may be of all other types.

Regardless, the capacity to supply electric power to the microcontroller is primordial. As a result, if the means 4 comprise one or more non-rechargeable batteries, it becomes necessary to carry out a maintenance operation aimed at replacing the said batteries whenever they are discharged or low. Sometimes, such a device 1 is scrapped altogether when the means for supplying electric power 4 are discharged.

To conserve the capacity of the means to supply electric power to a communicating device, a known technique consists in adapting the said device to add switching means aimed at connecting and disconnecting the microcontroller and the batteries. In that way, figure 2 makes it possible to illustrate a known mode of embodiment aimed at using a switch 5, such as an of/off type button that can be activated by the bearer of the device 1. The direct link 12 between the microcontroller 2 and the power 4 supply means 4 as presented in figure 1 is thus replaced by a discontinuous link 12a and 12b, connecting firstly the power supply means 4 to a button 5 and secondly the said button 5 to the microcontroller 4 respectively.

In that way, in a first operating mode, the bearer of the device 1 sets the button to the Start position to make the device operational. After use and in order to put the device into the idle position, the bearer releases the button 5 (if it is a push button) or sets it to Stop in order to break the connection between the power supply means 4 and the microcontroller 2.

Figure 3 illustrates a known alternative solution for conserving capacity of the power supply means 4 of a device

1. According to the technique, a device 1 comprises a microcontroller 2 that is connected 11 with receiving and/or transmitting means 3 and power supply means 4 respectively; the power supply means 4 take the form of one or more electric batteries, some of which are rechargeable.

The solution consists in adapting such a device to connect 13 the said rechargeable batteries to the receiving and/or transmitting means 3. Thus it is possible to use in part the field 30 generated to carry out communication between the device 1 and a terminal 20 to recharge the batteries. As a variant, such a device may have an antenna distinct from means 3 or any other means for using part of the field 30 to recharge the power supply means 4.

The known techniques mentioned above are generally found to be unsatisfactory. Thus, the known solution according to figure 1 leads to the premature scrapping of a device or expensive maintenance operations.

The technique according to figure 2 may also be expensive and unreliable. That is because the mechanical components generally used can rapidly show signs of wear and tear. The technique further requires action that is not easy for a wearer or user of a device. Such a button may further be accidentally pressed in view of the immediate environment of the device. The battery may thus be discharged rapidly, when the microcontroller of the device is switched on unintentionally and involuntarily.

Lastly, the technique according to figure 3 makes it necessary to equip the device with rechargeable batteries that are generally costly in terms of price and volume. Further, the partial and systematic recharging of the batteries when they are not necessarily and fully discharged reduces the intrinsic life of the batteries.

The invention makes it possible to do away with the drawbacks of the known solutions by adapting a communicating electronic device such as that described in relation to figure 1. Thus, it becomes possible to optimise the electricity consumption required for the working of the microcontroller and the communication means without using expensive and unreliable solutions and without penalising the user of the device by imposing a fastidious operating mode.

Figure 4 illustrates a first mode of embodiment of a device according to the invention. Thus, such a device 1 comprises a microcontroller 2 in connection 11 with communication means 3 for transmitting and/or receiving. It further includes means to supply electric power 4 in connection 12a and 12b with the said microcontroller 2. The link is established by means of switching means 7, for example of the logical latch type. Upon receiving a control signal, the means 7 are used to set up or break the link between the power supply means 4 and the microcontroller 2. To control the said switching means 7, the device comprises detection means 6 to detect a characteristic movement made voluntarily by the wearer of the device 1. The detection means 6 are a movement detector. For example, the said movement detector 6 comprises an accelerometer 6a. Indeed, there are different types of accelerometer - accelerometers with piezoelectric detection, piezoresistive detection, capacitive detection, inductive detection, optical detection etc. Some accelerometers comprise one or more vibrating beams or use surface waves. Others are made from electronic components such as capacitors using very low electric currents etc. Some crystals and some ceramics have the property of being charged electrically when they undergo deformation. The crystal is charged on two opposite sides with opposite charges when it is subjected to a force applied between the two sides. Metallising the sides makes it possible to collect voltage that may be used in a device. The known applications of an accelerometer are many: measurement of speed or displacement, vibration analysis, inclination measurement, impact detection etc. The invention offers a particularly innovative application of a movement detector such as an accelerometer. Indeed, depending on the nature of the accelerometer and the logic or the intelligence of the switching means 7, it is possible to detect a characteristic and voluntary movement by the wearer of the device 1. It is thus possible to model with some degree of accuracy a movement that the device may consider voluntary and expected to trigger the starting of the microcontroller 2. The detection means 6, comprising for instance an accelerometer, supply a command signal 14 to the switching means 7 after detecting the said characteristic movement. Upon receiving the said signal 14, the switching means 7 apply to the microcontroller the power available from the power supply means 4, leading to the starting of the said microcontroller 2. In a preferred mode of embodiment, at the end of the transaction carried out by the microcontroller, the microcontroller transmits a signal 15 to the switching means 7 to break the electric power supply. In that way, the power supply means and the microcontroller are disconnected and the capacity of the power supply means to supply electric power is conserved. As a variant, the microcontroller 2 can detect the absence of an electric field 30 required for communicating with the outside. In that case, after a predetermined period, the microcontroller supplies the said signal 15 and the electric power is no longer delivered by the means 4.

Figure 5 illustrates a variant of a device according to the invention. This variant relates to a device 1 comprising a microcontroller 2 in connection 11 with communication means 3 for transmitting and/or receiving. It further includes means to supply electric power 4 in connection 12 with the said microcontroller 2. Even though the latter is continuously connected to the electric power supply means 4, it only consumes very little power during the period when the microcontroller is on standby.

The device 1 comprises detection means 6 to detect a characteristic movement made voluntarily by the wearer of the device 1. For example, the said means 6 comprise an accelerometer 6a.

The detection means 6 supply a command signal 14 to the microcontroller 2 after detecting the said characteristic movement. Upon receiving the signal 14, the microcontroller exits standby and starts nominal operation which particularly allows it to communicate with the outside. Only when the microcontroller is in nominal operation mode does it consume more energy from the power supply means 4. In a preferred mode of embodiment, at the end of the transaction carried out by the microcontroller, the microcontroller switches back to the so-called "standby" mode which requires little electric power. In that way, the capacity of the power supply means to supply electric power is conserved. As a variant, the microcontroller 2 can detect the absence of an electric field 30 required for communicating with the outside. In that case, after a predetermined period, the microcontroller switches to the standby mode and the electric power requirements of the microcontroller drop to almost nothing.

Figure 6 makes it possible to illustrate a variant of embodiment in which the detection means 6 for detecting a characteristic movement by a wearer of the device comprise one or more sensors in order to refine the said movement detection. In that way, the detection means 6 may comprise a light detection sensor 6b. Thus, it is possible to detect the fact that the wearer of the device 1 has removed it from the storage space or a case. Such detection is liable to attest or confirm the imminent use of the device. Such a sensor 6b may be associated with an accelerometer 6a or any other pressure or impact sensor etc. The combination of several sensors may also improve the detection criteria of a characteristic movement by the wearer of the device.

Even though figure 6 preferably presents a mode of embodiment close to that described in connection with figure 5, it is fully possible according to the invention to use a combination of sensors as that described above to constitute detection means 6 as described in connection with figure 4, means to control switching means 7.

Regardless of the nature of the assembly for constituting detection means 6, it is desirable that the constituent elements such as an accelerometer 6a consume little or no power in relation to the consumption of the microcontroller when it communicates with the outside. For example, to make a badge with a smart card, the detection means 6 may consume a few microamperes while several milliamperes are required for powering the microcontroller of the smart card. The devices according to the invention are thus portable electronic devices with low electricity requirements that allow internal electric power supply means to have a very valuable long life, regardless of their nature, rechargeable or otherwise.

The invention has been described in a non-limitative way in association with the area of portable electronic objects such as contactless cards or smart cards. It may concern all portable electronic devices using a contactless communication protocol where it is important to conserve the capacity of the internal means capable of supplying electric power to a microcontroller.

Claims

1. A portable electronic device (1) comprising:

- a microcontroller (2),

- communication means (3) that work (1) with the said microcontroller (2) to transmit and/or receive radioelectric signals (30) to/from a terminal (20) in accordance with a contactless communication protocol,

- power supply means (4) to provide electric power to allow the operating of the microcontroller (2), the device being characterised:

- in that it further comprises a movement detector (6) to detect a characteristic voluntary movement by a wearer of the device and,

- in that the said detector (6) supplies an electric signal (14) to start the microcontroller and supply it with electric power from the power supply means (4) .

2. A device according to claim 1 where the movement detector (6) supplies the said electric signal to the microcontroller that leads to the starting up of the microcontroller.

3. A device according to claim 1 where the movement detector (6) supplies the said electric signal (14) to switching means (7) to apply to the microcontroller (2) the power available from power supply means (4), leading to the starting up of the said microcontroller.

4. A device according to claim 1 where the operating of the movement detector (6) requires an insignificant quantity or even no power at all with regard to the power required for the working of the microcontroller.

5. A device according to claim 1 where the movement detector (6) comprises passive electronic components .

6. A device according to claim 1 where the movement detector (6) comprises an accelerometer (6a).

7. A device according to claim 1 where the movement detector (6) comprises a light sensor (6b).

8. A device according to claim 1 where the microcontroller (2) interrupts its operating and controls (15) the suspension of the electric power supply following a predetermined time period of idleness .

9. A device according to claim 1 where the microcontroller interrupts its operating and controls (15) the suspension of the electric power supply in case of the absence of radioelectric field (30), which absence is detected by transmitting and/or receiving means (3) .