Access control system

Abstract

This building access control system includes a key (16) equipped with a backup circuit comprising: - a switch (Q2) capable: - in response to a continuous electrical closing signal, of switching to a closed state in which it maintains a microcontroller (140) of the key in an on mode, and - in the absence of the continuous electrical closing signal, of switching to an open state in which it switches the microcontroller (140) to an off mode, - a software module (158) which generates an alternating signal on an output port (148) of the microcontroller when executed by the microcontroller (140), - a capacitor (C3) electrically connected between the output port (148) and the switch (Q2), and - a rectifier (180) capable of transforming the alternating signal which has passed through the capacitor (C3) into a continuous electrical closing signal.

Description

[0001] The invention relates to an access control system. It also relates to a key and an electronic cylinder for implementing this access control system.

[0002] Known access control systems include a battery-powered key and an electronic cylinder without a battery. The electronic cylinder is powered only by the key's battery when the key is inserted into the cylinder. Such a system is described, for example, in application EP3431684A1.

[0003] In such a system, it is important to limit energy consumption as much as possible to extend the battery life of the key.

[0004] To achieve this, the keys of known systems contain a microcontroller that can switch between a standby mode and an on mode. In standby mode, an ignition module within the microcontroller continuously monitors for the presence of an ignition signal. This ignition module must be constantly powered by the key's battery; otherwise, it is unable to detect the arrival of the ignition signal.

[0005] The ignition signal is transmitted from the cylinder to the key when the key is inserted. In response to the ignition signal, the ignition module switches the microcontroller from standby to on mode. In on mode, the key's microcontroller interacts with the cylinder to, among other things, authorize or deny the opening of a door. Once authorization to open the door has been granted or denied, the key's microcontroller immediately returns to standby mode to conserve energy. The microcontroller can even return to standby mode before the key has been removed from the cylinder. This is advantageous for energy conservation.

[0006] The prior art is also known from EP3220362A1 and US2019206157A1. These applications concern the switching of the electronic cylinder microprocessor between an off and an on mode, and not the switching of the key microprocessor between an off and an on mode.

[0007] It is also important to ensure that the microcontroller consistently has enough time to complete all the operations it needs to perform, even if the key is prematurely removed from the cylinder.

[0008] The invention aims to provide an access control system that offers the above guarantee. It therefore relates to such a system conforming to claim 1.

[0009] The invention also relates to a key for the above access control system.

[0010] The invention will be better understood upon reading the following description, given solely by way of non-limiting example and made with reference to the drawings in which: there figure 1 is a schematic illustration of a door equipped with an electronic cylinder; the figure 2 is a schematic, perspective illustration of an access control system including the cylinder of the figure 1 and a key; the figure 3 is a schematic illustration, in vertical and longitudinal section, of the electronic cylinder of the figure 1 ; THE Figures 4 and 5 These are schematic illustrations of parts of electronic circuits implemented, respectively, in the key and electronic cylinder of the system. figure 2 ; there figure 6 is a flowchart of a process for the operation of the system of the figure 2 .

[0011] In these figures, the same numerical references are used to designate the same elements. In the remainder of this description, the characteristics and functions well known to a person skilled in the art are not described in detail.

[0012] This description first presents detailed examples of embodiments in Chapter I, with reference to the figures. Then, in Chapter II, variations of these embodiments are presented. Finally, the advantages of the different embodiments are presented in Chapter III. Chapter I: Examples of Implementation Methods

[0013] There figure 1Figure 2 represents a door 2 providing access to a building. This door 2 has an interior side, typically located inside a room, and an exterior side on the opposite side. Hereafter, the terms "interior" and "exterior" refer to the interior and exterior sides of door 2, respectively. Door 2 extends in a vertical plane. The vertical direction is subsequently designated by the Z direction of an orthogonal coordinate system XYZ. The X direction is perpendicular to the vertical plane in which door 2 primarily extends. All figures representing mechanical components are oriented with respect to this XYZ coordinate system.

[0014] Door 2 is equipped with a handle 4 and an electronic lock 6. To simplify the figure 1 , only part of gate 2 is shown.

[0015] The general mechanical architecture of lock 6 is, for example, identical to that described in applications FR3025236 and EP3431684. For this reason, only the details necessary for understanding the invention are given here. For further details, the reader is referred to those applications.

[0016] The lock 6 has a bolt 10 that can be moved in translation, parallel to the Y direction, alternately and reversibly between an extended and a retracted position. In the extended position, the bolt 10 protrudes beyond the edge of door 2 to engage in a strike plate fixed without any degree of freedom to the door frame 2. In the extended position, the bolt 10 locks door 2 in its closed position. In the retracted position, the bolt 10 is retracted inside door 2 and no longer protrudes beyond its edge. In the retracted position, door 2 can be moved by a user from a closed position to an open position by operating the handle 4.

[0017] The lock 6 also includes an electronic cylinder 12 and a screw 14 for fixing the cylinder 12 in the door 2.

[0018] Cylinder 12 can be moved between an unlocked position and, alternately, a locked position. In the unlocked position, il allows the opening of door 2 and therefore access to the building. In the locked position, il prohibits the opening of door 2 and therefore access to a building. To do this, the cylinder 12 moves the bolt 10 from its extended position to its retracted position when a key 16 ( figure 2 An authorized key, which unlocks lock 6, is inserted and then turned inside cylinder 12. Cylinder 12 also moves bolt 10 from its retracted position to its extended position when the authorized key is inserted and then turned in the opposite direction inside this cylinder. Conversely, when an unauthorized key is inserted into cylinder 12, this cylinder prevents bolt 10 from moving from its extended position to its retracted position.

[0019] Here, the key 16 can be inserted into the cylinder 12 from the outside and, alternately, from the inside of door 2. For this purpose, the cylinder 12 opens from each side of door 2.

[0020] The screw 14 has a head that is flush with the edge of the door 2. The threaded end of the screw 14 is screwed into the cylinder 12 to hold it in place inside the door 2.

[0021] Cylinder 12 lacks an internal power source. In particular, it lacks: of a battery capable of storing enough energy to allow the cylinder 12 to switch more than a hundred times between its unlocked and locked positions without external energy input, and of a mechanism capable of generating enough electricity to move the cylinder 12 into its unlocked position from, for example, the movement of the key inside the cylinder.

[0022] There figure 2 represents in more detail the access control system implemented using lock 6 and key 16.

[0023] Here, the cylinder 12 conforms to the European format. The cylinder 12 extends along a longitudinal axis 20 parallel to the X direction. It has a stator 22 fixed without any degree of freedom to the door 2 by means of the screw 14 and a cam 24 housed inside a transverse notch 26.

[0024] The notch 26 extends in a transverse plane 28 parallel to the Y, Z directions. Here, only a part of the plane 28 is shown on the figure 2 Plane 28 is a plane of symmetry for the bit 24.

[0025] The cam 24 rotates counterclockwise around the axis 20 to move the bolt 10 from its extended position to its retracted position and in the opposite direction to move the bolt 10 from its retracted position to its extended position.

[0026] Plane 28 also divides stator 22 into two parts. The part of stator 22 located on the inner side of gate 2 is called the "inner half-stator" and is designated by reference numeral 30. The part of stator 22 located on the outer side of gate 2 is called the "outer half-stator" and is designated by reference numeral 32. In this particular embodiment, half-stators 30 and 32 are almost symmetrical to each other with respect to plane 28. Thus, only half-stator 32 is described in more detail hereafter.

[0027] The half-stator 32 has a front cover 34 parallel to plane 28 and directly exposed on the outside of the door 2. This front cover prevents direct access to the moving parts located inside the cylinder 12, thus protecting them against break-in attempts. This cover 34 has an opening 36 through it, designed to receive a blade 38 of the key 16. The opening 36 is centered on the axis 20. The opening 36 is shaped to allow the blade 38 to be inserted into the cylinder 12 by a translational movement parallel to the X direction. The opening 36 is also shaped to allow the key 16, once inserted into the cylinder 12, to rotate about its axis 20.

[0028] Here, key 16 is an electronic key capable of transmitting an access code to cylinder 12 so that the latter, in response: allows the unlocking of cylinder 12 if the access code received is a valid access code that allows the key to open door 2, and alternatively prohibits the unlocking of cylinder 12 if the access code received is an invalid access code that does not allow the key to open door 2.

[0029] For this purpose, the key 16 includes a transceiver 40 and a battery 41.

[0030] Here, the blade 38 lacks a raised pattern designed to move the lock pins to mechanically unlock the lock 6. However, the blade 38 has at least one pattern capable of cooperating with a complementary pattern on a rotor of the cylinder 12 to cause this rotor to rotate when the key is turned. Here, this pattern on the blade 38 is a flat 42 located on its distal end.

[0031] The transceiver 40 is notably capable of transmitting, via an electrical link, the access code to cylinder 12.

[0032] Battery 41 is used here to power cylinder 12 via electrical connections. These electrical connections are established only when blade 38 is inserted into cylinder 12. For this purpose, blade 38 has electrical contacts adapted to cooperate with corresponding electrical contacts of cylinder 12 to establish these electrical connections between the key 16 and cylinder 12. By way of illustration, here, blade 38 has six electrical contacts arranged symmetrically on either side of its axis. For example, symmetrical contacts are part of the same conductive ring. In the figures, only contacts 44 to 46 located on the same side of blade 38 are visible.

[0033] There figure 3represents in more detail the interior of the cylinder 12. The stator 22 has a cylindrical channel 50, with a circular cross-section, passing through the stator 22 and therefore through the two half-stators 30 and 32. This channel 50 extends along the axis 20. Here, the axis 20 coincides with the axis of revolution symmetry of the channel 50.

[0034] Channel 50 receives a rotor 52. The rotor 52 is, for example, identical to the one described in more detail, in particular, with reference to the figures 5 and 6of application FR3025236. In particular, the rotor 52 has a housing 96 adapted to receive the end of the blade 38. The cross-section of this housing 96 has at least one shape complementary to the end of the blade 38 so as to be rotationally engaged by the blade 38. Here, this complementary shape is a flat adapted to engage with the flat 42 of the blade 38. Thus, when an authorized key is turned inside the lock 6, the rotation of the key 16 causes the rotation of the rotor 52, which in turn causes the rotation of the bit 24.

[0035] At its ends, channel 50 opens into cover 34 opposite orifice 36.

[0036] Here, the half-stator 32 comprises a shell 54 entirely located on the outside side of the plane 28 and half of a bar 56 located on the outside side of this plane 28. The bar 56 is symmetrical with respect to the plane 28.

[0037] The shell 54 comprises the front cover 34, the orifice 36, and half of the channel 50 located on the outer side. Preferably, the shell 54 is formed from a single block of rigid material. "Rigid material" or "rigid material" refers to a material whose Young's modulus at 25°C is greater than 100 GPa or 150 GPa, and preferably greater than 200 GPa.

[0038] The half-stator 32 includes a controllable mechanism 76 for unlocking the cylinder. This mechanism 76 is capable of moving a member 80 for blocking the rotation of the rotor 52. This mechanism 76 is fixed, without any degree of freedom, to the shell 54. For example, the mechanism 76 and the member 80 are similar or identical to those described in application FR3025236. To increase the readability of the figure 3 The representations of mechanism 76 and organ 80 have been simplified.

[0039] The component 80 moves in translation between a blocking position (represented on the figure 3and a retracted position. In the locked position, a distal end of the component 80 is received inside a recess in the rotor 52 to prevent the rotor from rotating about the axis 20. In the retracted position, the distal end of the component 80 is located outside the recess, so that the rotor 52 can be driven in rotation by the key 16 about the axis 20. For example, the component 80 moves only in translation between its locked position and its retracted position. Here, this translational movement is parallel to the Z direction.

[0040] The mechanism 76 typically includes an electrically controllable actuator 82 and an electronic control unit 84 for this actuator 82. In response to an unlocking command transmitted by the unit 84, the actuator 82 moves from an active position to an inactive position. In the inactive position, the component 80 can be freely moved from its locked position to its retracted position when the key 16 is turned inside the cylinder 12. In its active position, the actuator 82 holds the component 80 in its locked position. In the absence of an unlocking command, the actuator 82 is in its active position and the component 80 cannot be moved to its retracted position. Once the actuator 82 has reached its inactive position, it remains in its inactive position until the key 16 is removed from the cylinder 12. Typically, the actuator 82 is held in its inactive position without consuming any electrical energy.For example, for this purpose, it includes a magnet mechanism which holds it in its inactive position until the key 16 is removed. The movement of the actuator 82 from its inactive position to its active position is here mechanically driven by the movement of the key when it is removed from the cylinder 12.

[0041] Unit 84 is fit for duty: to receive the access code transmitted by the key inserted into the cylinder 12, then depending on the access code received, to transmit the unlocking command to the actuator 82 and, alternately, to inhibit the transmission of this unlocking command to maintain the component 80 in its locked position.

[0042] To authorize or, conversely, inhibit the transmission of the unlock command, unit 84 compares the received access code to pre-recorded access codes. If the received access code matches one of the pre-recorded access codes, then unit 84 transmits the unlock command. Otherwise, unit 84 does not transmit this unlock command.

[0043] Here, unit 84 communicates with transceiver 40 via an electrical link 106, which is established when key 16 is fully inserted into channel 50. Simultaneously, battery 41 transmits the energy required to power mechanism 76 via two electrical links 107 and 108. Link 106 is established via contact 44 and an electrical contact 100 of half-stator 32. Links 107 and 108 are established via contacts 45, 46, and two electrical contacts 101 and 102 of half-stator 32.

[0044] Electrical contacts 100 to 102 are, for example, structurally identical to each other. For example, these contacts 100 to 102 are implemented as described in application EP3431684.

[0045] There Figure 4represents the part of the key's electronic circuit 16 implemented to limit electrical energy consumption and thus extend the battery life 41.

[0046] Battery 41 has a negative electrode 120 and a positive electrode 122. Electrode 120 is at a lower electrical potential than electrode 122. On the figure 4 To simplify this figure, only electrodes 120 and 122 of battery 41 are shown. Battery 41 is, for example, a removable battery that can be replaced when its energy capacity becomes too low. For this purpose, the key 16 has electrical contacts 124 and 126 that make mechanical and electrical contact with electrodes 120 and 122, respectively, when battery 41 is inserted into the key 16.

[0047] The pads 124 and 126 are directly connected, respectively, to the electrical contacts 45 and 46 via electrical conductors, respectively, 128 and 130.

[0048] In this text, unless otherwise indicated, the term "connected" means "electrically connected". In this text, the expression "directly connected" means that two electrical components are connected to each other solely by a wired connection and therefore without passing through any other electrical or electronic component other than a wired connection.

[0049] Here, a wire connection or an electrical conductor is, typically, an electrical wire, for example of circular cross-section, or an electrical trace of a printed circuit board.

[0050] The transceiver 40 modulates the information to be transmitted to the cylinder 12 via the contact 44. Conversely, it demodulates the information received via the contact 44. For this purpose, the transceiver 40 is permanently connected between the terminal 126 and the electrical contact 44. More precisely, the transceiver 40 is connected to the terminal 44 by an electrical conductor 43.

[0051] Key 16 also includes a microcontroller 140 to manage interactions with cylinder 12 when it is powered. To power the microcontroller 140, it includes: a power supply port 142 directly connected to pin 126, and a power supply port 144 intended to be connected to the ground of key 16. The mass of the wrench 16 is equal to the electrical potential of electrode 120 when it is connected to that electrode. Conversely, when it is electrically isolated from electrode 120, the mass is floating.

[0052] Here, port 144 is also connected to contact 44 via diode CR1. The cathode of diode CR1 is directly connected to contact 44.

[0053] The microcontroller 140 also includes an input / output port 146 connected to the transceiver 40 for: transmit to the transceiver 40 the information to be modulated, then to be transmitted to cylinder 12, and receive the information transmitted by cylinder 12, then demodulate by the transceiver 40.

[0054] Typically, the information exchanged between the transceiver 40 and the microcontroller 140 is in baseband.

[0055] The 140 microcontroller has a 148 output port used to maintain its power supply.

[0056] The microcontroller 140 is only capable of switching between two different operating modes, called "off mode" and "on mode," respectively. In off mode, the microcontroller 140 does not operate and its power consumption is zero. In this respect, off mode differs from standby mode. In on mode, the microcontroller 140 executes pre-programmed instructions to manage the interactions of the key 16 with the cylinder 12. Here, the microcontroller 140 switches reversibly between its off and on modes. To do this, il The system switches between these two modes by electrically connecting and, alternately, disconnecting port 144 from electrode 120. When port 144 is disconnected from electrode 120, the microcontroller 140 is in its off mode. In this case, the ground of key 16 is also floating.

[0057] The 140 microcontroller includes: a non-volatile memory 152 containing instructions to be executed, and a microprocessor 154 capable of executing the instructions stored in memory 152.

[0058] Memory 152 includes, in particular, the instructions for an access control module 156 and a power supply maintenance module 158 for the microcontroller 140.

[0059] Memory 152 also contains access rights which allow the unlocking of cylinder 12 to be triggered. Here, the access rights of key 16 include in particular the access code to be transmitted to cylinder 12 to trigger its unlocking.

[0060] When executed, module 156 triggers the operations that manage the interaction of key 16 with cylinder 12 to alternately unlock and prevent the cylinder from being unlocked. Thus, module 156 includes instructions to send the access code from key 16 to cylinder 12 via port 146 and transceiver 40. Module 156 also includes an instruction to stop the power supply to microcontroller 140. This stop instruction is the last instruction executed by module 156 once all other operations have been completed. Therefore, the stop instruction is executed when key 16 has finished interacting with cylinder 12.

[0061] When executed by the microprocessor 154, the module 158 generates an alternating electrical signal on port 148 to maintain the power supply to the microcontroller 140. In this embodiment, for illustrative purposes, this alternating signal is a periodic square wave with a frequency f158. For example, the frequency f158 is equal to 2000 Hz. Here, the alternating signal is a square wave with a duty cycle of 50%. Thus, for 50% of the duration of a period of the alternating signal, it is equal to the positive potential of electrode 122, and for the remaining 50%, it is equal to the potential of electrode 120.

[0062] The execution of modules 156 and 158 begins as soon as the microcontroller 140 switches to its powered-on mode. Conversely, in powered-off mode, modules 156 and 158 are not executed. The execution of modules 156 and 158 stops when the stop instruction is executed.

[0063] Module 158 and port 148 are part of a backup circuit that keeps microcontroller 140 powered on even if key 16 is removed from cylinder 12. This backup circuit ensures that module 156 always executes to completion, even if key 16 is removed from cylinder 12 before all of module 156's operations are finished. In other words, it ensures that during normal operation of key 16, the shutdown instruction is executed. It also ensures that all data that module 156 needs to save to memory 152 before shutting down will be saved.

[0064] Furthermore, the backup circuit here is designed to quickly switch the microcontroller 140 to its off mode if the execution of module 156 stalls before reaching the stop instruction. Such a stall is caused, for example, by a code execution error. Such an error is more commonly known as a "bug".

[0065] For this purpose, this backup circuit includes a controllable switch Q2. Switch Q2 has a control terminal 160 and two power terminals 162 and 164. Terminal 162 is connected to the power supply port 144 of the microcontroller 140 via an insulated-gate field-effect transistor Q5, more commonly known as a MOSFET. (Metal Oxide Semiconductor Field Effect Transistor).

[0066] More specifically, transistor Q5 is an N-type MOSFET. Here, transistor Q5 is used to protect microcontroller 140 in case battery 41 is inserted into key 16 backwards. In this case, the positive potential is applied to pin 124 and not to pin 126. For this purpose, the source 170 of transistor Q5 is directly connected to pin 144, and its drain 172 is directly connected to pin 162 of switch Q2. The gate 174 of transistor Q5 is directly connected to pin 126. Thus, when the potential applied to pin 126 is positive, transistor Q5 is always in its closed state. If battery 41 is inserted backwards, the potential applied to the gate 174 is negative, and transistor Q5 is then in its open state. In this open state, it isolates port 144 from pin 124 and therefore protects microcontroller 140.

[0067] Switch Q2 is a normally open switch that toggles from an open state to a closed state in response to a continuous electrical closing signal. Switch Q2 remains in its closed state as long as the closing signal is present.

[0068] In the open state, switch Q2 electrically isolates terminals 162 and 164 from each other. The open state is the stable state of switch Q2; that is, the state to which it automatically returns when there is no command on terminal 160. When switch Q2 is in its open state and key 16 is removed from cylinder 12, the ground of the key 16's electronic circuit is not connected to any potential. In this case, the ground is floating. In such a situation, the microcontroller 140 is in its off mode.

[0069] In the closed state, switch Q2 connects terminals 162 and 164 so that port 144 is connected to pin 124. Thus, as long as switch Q2 is in its closed state, microcontroller 140 is in its on mode.

[0070] For example, switch Q2 is an N-type MOSFET transistor. In this case, terminals 160, 162, and 164 correspond to the gate, drain, and source of this transistor, respectively. Switch Q2 is in its closed state when the voltage VGS between terminals 160 and 164 exceeds a predetermined positive threshold Sth. Thus, in this case, the closing signal is a positive potential.

[0071] The closing signal that keeps switch Q2 in its closed state is generated from the alternating holding signal by a rectifier 180. The rectifier 180 is also part of the backup circuit.

[0072] Rectifier 180 is connected to port 148 via capacitor C3.

[0073] The 180 rectifier includes: a diode CR5 whose anode is directly connected to capacitor C3 and whose cathode is directly connected to terminal 160 of switch Q2, a capacitor C4 directly connected between terminals 160 and 164 of switch Q2, a resistor R1 directly connected between terminals 160 and 164 of switch Q2, and a diode CR4 whose cathode is directly connected to capacitor C3 and whose anode is directly connected to terminal 164 of switch Q2.

[0074] The backup circuit keeps the 140 microcontroller in its powered-on mode. However, it cannot switch the 140 microcontroller from its powered-off mode to its powered-on mode. This is because the backup circuit can only generate the alternative hold signal if module 158 is being executed by the 140 microcontroller. This assumes that the 140 microcontroller is already powered on.

[0075] In this embodiment, the key 16 is devoid of any ignition circuit of the microcontroller 140 and such an ignition circuit is located only inside the cylinder 12 control unit 84.

[0076] Key 16 also includes a filter capacitor C6 connected between pin 126 and the ground of the electronic circuit of key 16.

[0077] There figure 5represents the part of the electronic circuit of the cylinder control unit 84 implemented to turn on the microcontroller 140 in response to the insertion of the key 16 into the lock 12.

[0078] Unit 84 includes a microcontroller 200 and a transceiver 202.

[0079] The 200 microcontroller includes: a power supply port 204 connected to the electrical contact 101 by an electrical conductor 206, a power supply port 208 connected to the electrical contact 102 by an electrical conductor 210.

[0080] When the contacts 45, 46 of the key 16 are in contact with, respectively, the contacts 101 and 102, the meeting of the electrical conductors 128 and 206 forms the electrical link 107 and the meeting of the electrical conductors 130 and 210 forms the electrical link 108. Thus, when the key 16 is inserted into the cylinder 12, the microcontroller 200 is powered by the battery 41.

[0081] The 200 microcontroller also includes: a non-volatile memory 216 containing instructions to be executed to interact and communicate with the key 16, and a microprocessor 218 capable of executing the instructions stored in the memory 216.

[0082] Memory 216 contains, in particular, the instructions for a microcontroller 140 ignition module 220 and an access control module 222. It also contains access rights to authorize and, alternately, prohibit the movement of cylinder 12 to its unlocked position.

[0083] When module 222 is executed by microprocessor 218, microprocessor 218 receives the access code from key 16 and compares it to the access rights stored in memory 216.

[0084] Module 220 is configured to trigger the generation of a switch closing signal Q0 in response to the power-up of microcontroller 200. Module 220 also maintains the closing signal for a predetermined duration D1, long enough for the key backup circuit 16 to activate and thus keep microcontroller 140 in its powered-on state. Furthermore, this duration D1 is short enough that the switch closing signal Q0 always stops before microcontroller 140 executes the stop instruction.

[0085] The microcontroller 200 also includes a communication port 212 through which information to be exchanged with the key 16 is transmitted and received. This port 212 is connected to the transceiver 202. The transceiver 202 encodes and, alternately, decodes the information exchanged with the key 16. For this purpose, it is directly connected to the electrical contact 100 by an electrical conductor 224. When the electrical contact 100 is in contact with the contact 44, the joining of the electrical conductors 43 and 224 forms the electrical connection 106.

[0086] The Q0 switch in unit 84 toggles between an open state and a closed state. The Q0 switch comprises: a 230 power terminal directly connected to the electrical contact 100, a 232 power terminal directly connected to the electrical contact 101, and a 234 control terminal directly connected to the transceiver 202.

[0087] In the closed state, switch Q0 connects terminals 230 and 232 together. Conversely, in the open state, switch Q0 electrically isolates terminals 230 and 232 from each other. The stable state of switch Q0 is the open state. Switch Q0 switches from its open state to its closed state in response to a closing electrical signal received at its terminal 234. As long as the closing signal is present at terminal 234, switch Q0 remains in its closed state. Here, the closing signal is transmitted to switch Q0 by the transceiver 202. Thus, in this embodiment, the microcontroller 140's power-on circuit comprises module 220 and transceiver 202.

[0088] The operation of the access control system will now be described with reference to the process of the Figure 6 .

[0089] During an initial step 300, key 16 is removed from cylinder 12. During this step 300, transistor Q2 is in its open state. Microcontroller 140 is therefore in its off state and its power consumption is zero. Simultaneously, microcontroller 200 is also not powered, and the power consumption of cylinder 12 is zero.

[0090] In step 302, the key 16 is inserted into the cylinder 12. During this step, the blade 38 is inserted through the orifice 36 and then pushed into the cylinder 12. The electrical contacts 44 to 46 then come directly into contact with, respectively, the electrical contacts 100 to 102. The electrical connections 106 to 108 are then established.

[0091] In step 304, once the electrical connections 106 to 108 are established, the ports 204 and 208 of the microcontroller 200 are connected to the electrodes 120 and 122 of the battery 41. The microcontroller 200 is therefore powered by the battery 41. At this stage, the microcontroller 140 is still not powered because its port 144 is electrically isolated from the pin 124 by the switch Q0 which is in its open state.

[0092] In step 306, the microcontroller 200 begins by executing the ignition module 220. The execution of module 220 triggers the generation of the shutdown signal by the transceiver 200.

[0093] During step 308, in response, switch Q0 toggles to its closed state. It remains in this closed state for the entire duration D1. From then on, port 144 of microcontroller 140 is now connected to pin 124 and electrode 120 via switch Q0 and electrical connections 106 and 107. Microcontroller 140 therefore now switches to its powered mode.

[0094] During step 310, as soon as the microcontroller 140 is in its powered mode, it executes module 158. This triggers the generation of the alternating hold signal.

[0095] During step 312, since the hold signal is an alternating current (AC) signal, it can pass through capacitor C3. The frequency f158 of the AC hold signal is high enough that capacitor C4 charges faster than it discharges through resistor R1. Thus, the AC hold signal charges capacitor C4, which then applies a positive potential to pin 160 of switch Q2. This causes switch Q2 to switch to its closed state. From this point on, pin 144 of microcontroller 140 is connected to pin 124 and electrode 120 via switch Q2. As mentioned earlier, the AC hold signal is generated until the stop instruction is executed by microcontroller 140.

[0096] During step 314, at the end of duration D1, the power-on circuit interrupts the generation of the closing signal for switch Q0. Switch Q0 then returns to its open state. However, this does not return the microcontroller 140 to its off state, as it is now maintained in its powered-on state by the backup circuit.

[0097] An access control phase 316 then begins. During this phase 316, the access control modules 156 and 222 are executed by the microcontrollers 140 and 200, respectively. During phase 316, the key 16 sends, via the link 106, an access code to the microcontroller 200. The microcontroller 200 compares this access code to the access rights stored in its memory 216 to determine whether it is a valid access code. If it is a valid access code, the unit 84 commands the actuator 82 to move the cylinder 12 to its unlocked position. Conversely, if the received access code is invalid, no unlock command is sent to the actuator 82, and the cylinder 12 remains in its locked position. Whether the received access code is valid or not, phase 316 ends with the execution of the stop instruction by microcontroller 140.

[0098] During step 318, in response to the execution of the stop instruction, microcontroller 140 ceases generating the alternating hold signal. Capacitor C4 then discharges through resistor R1, and the potential applied to pin 160 becomes zero. Switch Q2 then returns to its open state, and port 144 is electrically isolated from pin 124. Microcontroller 140 is thus returned to its off state.

[0099] It should be noted that the microcontroller 140 can return to its off mode even before the key 16 has been removed from the cylinder 12. This is due in particular to the switch Q0 which allows the port 144 to be isolated from the pin 124 even if the key is still inserted inside the cylinder 12. Thanks to this, energy is saved.

[0100] Conversely, the microcontroller 140 can remain in its powered-on mode, even if the key 16 is removed from the cylinder 12, to ensure that the module 156 always executes to completion. Thus, a rapid removal of the key 16 cannot lead to malfunction or unexpected operation of the key 16. In particular, the backup module ensures that all data to be saved in memory 152 is correctly saved there.

[0101] Finally, if the code execution by microcontroller 140 stalls, this also causes the execution of module 158 to stall. When the execution of module 158 stalls, the signal generated on port 148 is a continuous signal. Such a continuous signal is not transmitted to the rectifier 180 because it is filtered by capacitor C3. Consequently, capacitor C4 discharges and switch Q2 returns to its open state. This allows the microcontroller 140 to switch to its off state even if, due to a code execution failure, it remains stalled. This prevents the battery 41 from being discharged in case of a malfunction of microcontroller 140. CHAPTER II: VARIANTS Ignition circuit variations:

[0102] Other embodiments of the ignition circuit are possible. For example, in one particular embodiment, the electrical contact 44 is electrically connected to terminal 160 of switch Q2. In this case, the closing signal generated by the ignition circuit is directly transmitted to this terminal 160, causing switch Q2 to close even before the backup circuit is activated. For this purpose, for example, switch Q0 is connected between contacts 100 and 102, rather than between contacts 100 and 101. Under these conditions, closing switch Q0 results in a positive voltage being applied to terminal 160, thus closing switch Q2.

[0103] What has been described here in the particular case where it is the power port 144 which is used to switch the microcontroller 140 between its off and on modes, can also be applied and transposed to the case where it is port 142. In this latter case, port 144 is then, for example, permanently connected to pin 124.

[0104] In another embodiment, the switch Q0 is housed inside the key 16. In this case, the terminal 234 is connected to the ignition circuit located inside the cylinder 12 via an additional pair of electrical contacts fixed, respectively, to the key 16 and the cylinder 12. This additional pair of contacts is used to establish an additional electrical connection which connects the output of the ignition circuit to the terminal 234 of the switch Q0 located inside the key 16.

[0105] The ignition circuit can also be housed inside the key 16. In this case, at least one of the electrical connections used to power the ignition circuit passes through two pairs of electrical contacts selected from the group consisting of contact pair 46, 102, contact pair 44, 100, and contact pair 45, 101. Preferably, only one of the two electrical connections required to power the ignition circuit passes through two of these contact pairs, and the other electrical connection is directly connected to one of the terminals 124, 126. Thus, as long as the key is removed from cylinder 12, the ignition circuit is not powered. However, when the key 16 is inserted into cylinder 12, the ignition circuit is powered. The ignition circuit can then generate the closing signal for switch Q0.In this latter embodiment, preferably, the switch Q0 is also housed inside the key 16.

[0106] In another embodiment, the closing signal of switch Q0 is directly transmitted to terminal 234 by microcontroller 200 without going through transceiver 202. Backup circuit variations:

[0107] Other forms of alternative signals are possible for the holding signal. For example, the alternative holding signal can be a sawtooth signal, a sinusoidal signal, or another type.

[0108] In another embodiment, the backup circuit includes a hold signal generator independent of the microcontroller 140. In this case, the software module 158 is omitted. Typically, this independent generator is a hardware circuit independent of the microcontroller 140. Preferably, this independent hold signal generator is configured to automatically stop generating the hold signal after a predetermined and constant time D2 has elapsed since the key was removed from the cylinder. This time D2 is long enough to ensure that the module 156 has completed its execution. The time D2 is also ten, one hundred, or one thousand times shorter than the time required to consume all the energy initially stored in the battery 41. In this case, the stop instruction is not used to stop the generation of the hold signal.

[0109] Other embodiments of the 180 rectifier are possible. For example, the rectifier can be a diode Graetz bridge. Other variations :

[0110] Alternatively, cylinder 12 has its own power supply. In this configuration, cylinder 12 is not powered by battery 41 but by its own power source. However, even in this case, the ignition circuit is powered by battery 41.

[0111] The information transmitted between cylinder 12 and key 16 can be exchanged differently than previously described. For example, information is exchanged between the key and cylinder solely via electrical connections 107 and 108, without using connection 106. In another embodiment, the exchange of information between key 16 and cylinder 12 is carried out wirelessly. In this latter case, electrical connection 106 is used only to switch the microcontroller 140 from its off to its on mode.

[0112] The exchange of the access code between the key and the cylinder can also occur in the reverse direction. For example, the cylinder transmits an access code to the key 16, and then the microcontroller 140 of the key 16 compares the received access code to a pre-recorded list in its memory 152 of electronic cylinder access codes that this key 16 is authorized to unlock. If the received access code belongs to this pre-recorded list, the key 16 generates an unlock command, which is transmitted to the cylinder 12 via the connection 106. In response to receiving this unlock command, the cylinder 12 switches to its unlocked position. If the received access code does not belong to this pre-recorded list, the unlock command is not transmitted to the cylinder 12.

[0113] The electrical contacts of the key and the cylinder can be located elsewhere. For example, alternatively, the electrical contacts of the key are located on the key's grip body and the electrical contacts of the cylinder are located on the front cover 34. In such an embodiment, the electrical contacts are not located on the blade 38 and inside the channel 50.

[0114] In another embodiment, the battery 41 is not a removable battery. Transistor Q5 can then be omitted and replaced by a simple wire connection that links terminal 162 of switch Q2 to port 144 of microcontroller 140.

[0115] The backup circuit can be implemented independently of the microcontroller 140's ignition circuit, which is powered via an electrical connection established only when the key is inserted into the cylinder. For example, the backup circuit can also be implemented in a system where the microcontroller 140's ignition circuit is housed inside the key and continuously powered by the battery 41. CHAPTER III: ADVANTAGES OF THE IMPLEMENTATION METHODS DESCRIBED

[0116] The backup circuit ensures that the microcontroller 140 always has enough time to complete all the operations it needs to perform, even if the key 16 is prematurely removed from the cylinder 12. Furthermore, because the alternative hold signal is generated by a software module run by the microcontroller 140 and transmitted through capacitor C3, it is guaranteed that if the execution of the microcontroller 140's code is blocked, the microcontroller 140 will necessarily switch to its off mode, well before all the energy stored in battery 41 is consumed. In other words, if the microcontroller 140 malfunctions, it is systematically and automatically switched off.

[0117] The fact that the ignition circuit and / or switch Q0 are housed inside cylinder 12 simplifies the architecture of key 16.

[0118] When at least one of the electrical connections linking the ignition circuit to the battery 41 passes through the electrical contacts 44 to 46, the ignition circuit's power supply is systematically cut off when the key is removed from cylinder 12. Consequently, when the key is removed from the cylinder, the ignition circuit no longer consumes electrical power. This conserves the electrical energy stored in the key's battery 41. In particular, this limits the power consumption of the key 16 while still allowing the microcontroller 140 to switch from its off to its on state when the key is inserted into cylinder 12. This ignition circuit also remains capable of controlling the switching of switch Q0 from its closed to its open state even before the key 16 is removed from cylinder 12.It is therefore possible to switch the microcontroller 140 to its off mode before the key 16 is removed. This also saves battery 41.

[0119] Powering the ignition circuit from battery 41 helps to limit the electrical consumption of cylinder 12 since this ignition circuit is only powered when the key 16 is inserted into this cylinder.

[0120] Using the key's electrical contacts to cut off the power to the ignition circuit simplifies the key's design.

[0121] Using the same electrical connection 106 between the key and the cylinder to first control the ignition of the microcontroller 140 and then to exchange information between the cylinder 12 and the key 16 allows the number of electrical contacts between the key and the cylinder to be limited.

Claims

1. Building access control system, this system comprising: - an electronic lock cylinder (12) movable between an unlocked position in which it allows access to the building and, alternately, a locked position in which it prohibits access to the building, - a key (16) comprising: - a battery (41) equipped with first and second electrodes (120, 122), respectively, at a first and second electrical potential, - first and second electrical terminals (124, 126) electrically connected, respectively, to the first and second electrodes of the battery, - a microcontroller (140) equipped with a power supply port (144), this power supply port being capable: - when the power supply port is electrically isolated from the second electrical terminal, of switching the microcontroller into an off mode in which the electrical energy consumption of the microcontroller is zero,and alternately - when the power supply port is electrically connected to the second electrical pin, to switch the microcontroller into an on mode in which the microcontroller is able to exchange information with the electronic cylinder to trigger the movement of the electronic cylinder to its unlocked position, - a first switch (Q0) having a control terminal (234), this first switch being able, in response to receiving an electrical closing signal on its control terminal, to switch, when the key is inserted inside the cylinder: - from a stable open state in which it electrically isolates the power supply port (144) of the microcontroller (140) from the second pin (124), - to a closed state in which it electrically connects the power supply port (144) to the second pin (124), thus switching the microcontroller into its on mode, and - an ignition circuit for the microcontroller (140) of the key,when powered, to generate the electrical closing signal on the control terminal (234) of the first switch (Q0) in response to the insertion of the key into the electronic cylinder, - a first and a second electrical connection (107, 108) which connect the ignition circuit, respectively, to the first and second electrical terminals (124, 126) to power this ignition circuit when the key is inserted into the electronic cylinder, - a first, a second and a third electrical contact (45, 46, 44) fixed to the key and a fourth, a fifth and a sixth electrical contact (101, 102, 100) fixed to the electronic cylinder, the first, second and third electrical contacts being capable of making mechanical and electrical contact, respectively, with the fourth, fifth and sixth electrical contacts when the key is inserted into the electronic cylinder, characterized in thatThe key includes a backup circuit capable of maintaining the microcontroller (140) in its on mode even after the key has been removed from the electronic cylinder. This backup circuit comprises: - a second switch (Q2) having a control terminal (160), this second switch being capable: - in response to a continuous electrical closing signal, of switching to a closed state in which it electrically connects the power supply port (144) to the second terminal (124) to maintain the microcontroller in its on mode, and - in the absence of the continuous electrical closing signal, of switching to an open state in which it electrically isolates the power supply port from the second terminal of the battery to switch the microcontroller to its off mode, - an output port (148) of the microcontroller.- a software module (158) for maintaining power, capable of generating an alternating power-maintaining signal on the output port (148) when executed by the microcontroller (140), - a capacitor (C3) electrically connected between the output port and the control terminal (160) of the second switch (Q2) to carry the alternating power-maintaining signal, and - a rectifier (180) capable of converting the alternating power-maintaining signal that has passed through the capacitor (C3) into a continuous electrical closing signal applied to the control terminal (160) of the second switch.

2. System according to claim 1, wherein at least the first electrical connection (107) is established via the first and fourth electrical contacts (45, 101).

3. System according to claim 2, wherein the ignition circuit is housed inside the electronic cylinder.

4. System according to claim 3, wherein the first switch (Q0) is housed inside the electronic cylinder.

5. System according to any one of the preceding claims, wherein the ignition circuit is capable of generating, before the key is removed from the electronic cylinder, an electrical opening signal on the control terminal of the first switch (Q0) which causes the first switch to switch from its closed state to its open state.

6. System according to any one of the preceding claims, wherein the key comprises: - an access control software module (156) which, when executed by the microprocessor (140) of the key, causes the execution of all the operations programmed to manage the interaction of the key with the electronic cylinder, this set of operations ending with a stop instruction from the microprocessor of the key, and - in response to the execution of the stop instruction by the microprocessor of the key, the hold software module (158) is configured to stop the generation of the alternating power-hold signal, and - the ignition circuit is configured to automatically generate, before the execution of the stop instruction, an electrical opening signal on the control terminal of the first switch (Q0) which causes the first switch to switch from its closed state to its open state.

7. System according to any one of the preceding claims, wherein the second switch (Q2) is connected in parallel with the first switch (Q0) when the key is inserted into the electronic cylinder.

8. System according to any one of the preceding claims, wherein: - the key comprises a first signal transmitter-receiver (40) connected to the third electrical contact (44) by an electrical conductor (43), this first transmitter-receiver being capable of exchanging information between the key and the electronic cylinder via the third electrical contact, - the cylinder comprises a second signal transmitter-receiver (202) connected to the sixth electrical contact (100) for exchanging information between the key and the electronic cylinder via an electrical information transmission link (106) passing through the third and sixth electrical contacts (44, 100) when the key is inserted inside the electronic cylinder,- The first switch (Q0) is electrically connected between the electrical information transmission link (106) and the second electrical terminal (124) when the key is inserted into the electronic cylinder, in order to use this same electrical information transmission link to switch the microcontroller into its powered mode.

9. System according to any one of the preceding claims, wherein - the key comprises a blade (38) adapted to be inserted into a key channel of the electronic cylinder, this blade comprising each electrical contact (44-46) of the key, and - the electronic cylinder comprises a key channel (50) adapted to receive the key blade and each electrical contact (100-102) of the electronic cylinder is located inside this key channel.

10. System according to any one of the preceding claims, wherein the electronic cylinder is powered solely by the key's battery (41) when the key is inserted into this electronic lock.

11. Key for implementing a system according to any one of the preceding claims, wherein the key comprises: - a battery (41) equipped with first and second electrodes (120, 122), respectively, at a first and second electrical potential, - first and second electrical terminals (124, 126) electrically connected, respectively, to the first and second electrodes of the battery, - a microcontroller (140) equipped with a power supply port (144), this power supply port being capable: - when the power supply port is electrically isolated from the second electrical terminal (124), of switching the microcontroller into an off mode in which the electrical energy consumption of the microcontroller is zero, and alternately - when the power supply port is electrically connected to the second electrical terminal (124),to switch the microcontroller into an on mode in which the microcontroller is able to exchange information with the electronic cylinder to trigger the movement of the electronic cylinder to its unlocked position, - a first, a second and a third electrical contacts (44-46) able to make mechanical and electrical contact with respective electrical contacts fixed to the electronic cylinder to form, respectively, a first, a second and a third electrical links (106-108) which electrically connect the electronic cylinder to the key when the key is inserted into the electronic cylinder, the first and second electrical contacts (45, 46) being connected, respectively, to the first and second electrical terminals (124, 126) to power the electronic cylinder from the key's battery, , characterized in thatThe key includes a backup circuit capable of maintaining the microcontroller (140) in its on mode even after the key has been removed from the electronic cylinder. This backup circuit comprises: - a switch (Q2), called the second switch, having a control terminal (160). This second switch is capable: - in response to a continuous electrical closing signal, of switching to a closed state in which it electrically connects the power supply port (144) to the second terminal (124) to maintain the microcontroller in its on mode, and - in the absence of the continuous electrical closing signal, of switching to an open state in which it electrically isolates the power supply port from the second terminal of the battery to switch the microcontroller to its off mode; - an output port (148) of the microcontroller.- a software module (158) for maintaining power, capable of generating an alternating power-maintaining signal on the output port (148) when executed by the microcontroller (140), - a capacitor (C3) electrically connected between the output port and the control terminal (160) of the second switch (Q2) to carry the alternating power-maintaining signal, and - a rectifier (180) capable of converting the alternating power-maintaining signal that has passed through the capacitor (C3) into a continuous electrical closing signal applied to the control terminal (160) of the second switch.

12. Key according to claim 11, wherein: - the key is devoid of an ignition circuit capable, when powered, of switching the key's microcontroller from its off mode to its on mode in response to the insertion of the key into the electronic cylinder, and - the third electrical contact (44) is connected: - to the power supply port (144) of the key's microcontroller, or - to the control terminal of a first switch, housed inside the key, which is capable of switching from an open state in which it electrically isolates the power supply port (144) of the microcontroller (140) from the second electrical pin (124) to a closed state in which it connects the power supply port of the microcontroller to the second electrical pin.

13. Key according to any one of claims 11 to 12, wherein the key comprises: - an access control software module (156) which, when executed by the microprocessor (140) of the key, causes the execution of all the operations programmed to manage the interaction of the key with the electronic cylinder, this set of operations ending with a stop instruction of the microprocessor of the key, and - in response to the execution of the stop instruction by the microprocessor of the key, the hold software module (158) is configured to stop the generation of the alternating power-hold signal.

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