Electronically controlled door latch arrangement

Abstract

The invention relates to an electronically controlled door latch arrangement for a vehicle (17), the arrangement comprising an external device (2), a supercapacitor group (3) and a current limiter (4), wherein the supercapacitor group (3) is galvanically conductively connected to the external device (2) via the interconnected current limiter (4), the supercapacitor group (3) is chargeable with a main supply power provided by a main power source (5) of the vehicle (17) during a normal operating state, such that in the event of an unavailability of the main supply power, an auxiliary supply power is provided to the external device (2) employing the supercapacitor group (3) during a backup operating state, and the current limiter (4) is configured to interrupt a current to the external device (2) from the supercapacitor group (3) at a predetermined current limit value, such that the charge in the supercapacitor group (3) is maintained. In this way an easy, cheap and reliable solution for feeding an electronically controlled door latch with power in long term parking situations is provided.

Description

[0001] The invention relates to an electronically controlled door latch arrangement for a vehicle, the arrangement comprising an external device and a supercapacitor group, wherein the supercapacitor group is galvanically conductively connected to the external device via the interconnected current limiter, the supercapacitor group is chargeable with a main supply power provided by a main power source of the vehicle during a normal operating state, such that in the event of a unavailability of the main supply power, an auxiliary supply power is provided to the external device employing the supercapacitor group during a backup operating state. The invention further relates to the use of the electronically controlled door latch arrangement on a door of the vehicle, the vehicle comprising the electronically controlled door latch arrangement and a method for operating the electronically controlled door latch arrangement.Background

[0002] Several automotive systems require the presence of a backup power source in a vehicle to provide electrical power to replace or support a main power source of the vehicle in the event of a failure or interruption of that main power source. Such a backup power source is typically kept charged by the vehicle's main power source during normal operation such that it is immediately available when needed, such as in the event of an accident or impact to the vehicle.

[0003] As electronically controlled door latches, or eLatches for short, increasingly replace purely mechanical door latches, the question of how to unlock a door in the absence of a main or emergency power source is an important safety issue. If mechanical Bowden cables or levers for electronically controlled door latches are also missing, it can become very difficult to open a car door without power. This can be the case after an accident or damage to the vehicle. These eLatches often occur together with other devices such as electronically actuated door handles on the door of the vehicle or further control units (ECUs).

[0004] In addition, vehicle manufacturers are increasingly focusing on long-term parking situations where an electronic control unit directly manages the power supply to an eLatch and enters a sleep mode to conserve power. The current state of the art is supercapacitors as storage elements, which provide a reserve for a few days. In a specific case where the main power source fails during prolonged periods of inactivity, such as the long-term parking situation, the supercapacitors can ensure the eLatch's power supply for a certain period of time. A general problem with supercapacitors, however, is the high discharge rate. Particularly in the long-term parking situation mentioned above, it is therefore questionable how long the supercapacitors will be able to supply the eLatch with power if the main power source fails, such that it can still be operated even after a longer parking situation. This is particularly the case if the eLatch is used together with the devices mentioned above, which can only be operated electrically and whose supply of electrical power must also be ensured in the situations mentioned here, as this is the only way to ensure access to the vehicle, for example.Summary of invention

[0005] It is therefore an object of the invention to provide an easy, cheap and reliable solution for feeding an external device with power in long term parking situations.

[0006] The object of the invention is solved by the features of the independent claims. Preferred implementations are detailed in the dependent claims.

[0007] Thus, an electronically controlled door latch arrangement for a vehicle is provided, the arrangement comprising an external device, a supercapacitor group and a current limiter, wherein the supercapacitor group is galvanically conductively connected to the external device via the interconnected current limiter, the supercapacitor group can be charged with a main supply power provided by a main power source of the vehicle during a normal operating state, such that in the event of an unavailability of the main supply power, an auxiliary supply power is provided to the external device employing the supercapacitor group during a backup operating state, and the current limiter is configured to interrupt a current to the external device from the supercapacitor group at a predetermined current limit value, such that the charge in the supercapacitor group is maintained.

[0008] Therefore, the external device is usually powered from the main power source during normal operation. The external device is then used to open or close a door of the vehicle. Finally, in the event of a failure or unavailability of the main supply power, the supercapacitor group provides an auxiliary supply power that can be used to operate in the absence of the main supply power. Since the supercapacitor group continuously loses charge, e.g. in a permanent parking situation, this is counteracted by the current limiter. The current limiter is an electronic circuit or device used to limit and control the flow of current in an electrical circuit. In this case, the current limiter is a component that monitors the current coming from the supercapacitor group to determine if the predetermined current limit value has been reached and then causes the galvanic connection between the supercapacitor group and the external device to be interrupted. If, however, the predetermined current limit value is not reached, the current limiter transmits the auxiliary supply power provided by the supercapacitor group so that the external device can be actuated. In principle, various external devices can be provided in this way. According to a preferred embodiment of the invention, however, the external device is an electronically actuated door handle or a further control device. The electronically actuated door handle is designed in such a way, that it is not operated mechanically, i.e. is integrated flush into a vehicle body on a door of the vehicle, for example, and must therefore also be supplied with electrical power via the auxiliary supply power if the main supply power fails.

[0009] It is therefore essential to the invention that the current limiter monitors the current coming from the supercapacitor group and, above the predetermined current limit value, causes the galvanically conductive connection between the supercapacitor group and the electronically actuated door latch to be interrupted, such that the charge in the supercapacitor group is maintained. The predetermined current limit value does not have to be reached exactly; rather, the predetermined current limit value provides a limit value above which the galvanically conductive connection between the supercapacitor group and the external device is interrupted. By interrupting the galvanically conductive connection between the supercapacitor group and the external device, the auxiliary supply power is maintained in the form of the charge in the supercapacitor group, such that this supercapacitor group does not discharge, and the external device is provided with auxiliary supply power in the backup operating state even in long term parking situations.

[0010] In principle, it is possible to set the predetermined current limit value in different ways. According to a preferred embodiment of the invention, however, the predetermined current limit value corresponds to the auxiliary supply power from the supercapacitor group. In this way the predetermined current limit value is adapted and takes into account the available auxiliary supply power, such that a complete discharge of the supercapacitor group cannot occur, but rather at least a reserve is maintained, after which it is still ensured that the external device is supplied with sufficient power to be actuated.

[0011] It is possible to interrupt the discharge of the supercapacitor group in different states. According to a preferred embodiment of the invention, however, the current limiter is configured for interrupting the current only in the backup operating state. This prevents unnecessary interruptions with the current limiter when there is already enough power to supply the external device via the main supply power.

[0012] In general, it is possible to interrupt the galvanically conductive connection between the supercapacitor group and the external device in various ways. According to a preferred embodiment of the invention, however, the electronically controlled door latch arrangement additionally comprises a switch galvanically conductively connected between the current limiter and the external device, wherein the current limiter is connected to the switch for signal transmission, such that the switch interrupts the galvanically conductive connection between the supercapacitor group and the external device in response to a signal or the absence of a signal from the current limiter at the predetermined current limit value. The switch is a simple, inexpensive and, above all, fast switching component. So if the current limiter registers that the supercapacitor group is discharging and the current detected by the current limiter reaches or exceeds the predetermined current limit value, the switch with the current limiter is configured to interrupt this connection such that the auxiliary supply power in the supercapacitor group is maintained.

[0013] According to a particularly preferred further embodiment of the invention, the electronically controlled door latch arrangement comprises a galvanically connected field-effect transistor between the current limiter and the external device, wherein a source terminal of the field-effect transistor is galvanically conductively connected to the current limiter, wherein a drain terminal of the field-effect transistor is galvanically conductively connected to the external device, wherein the current limiter is connected to a gate terminal of the field-effect transistor for transmitting the signal, wherein the current limiter is configured for transmitting a signal when the current is below the predetermined current limit value, such that the field-effect transistor is switched through, and the current limiter is further configured for terminating the signal transmission at the predetermined current limit value, such that the galvanically conductive connection between the supercapacitor group and the external device is interrupted. The field-effect transistor is ideal for temporarily separating the supercapacitor group from the external device. In the absence of a corresponding signal from the current limiter, the field effect transistor is no longer continuous and thus blocks or interrupts the connection. If, on the other hand, the power output, i.e. the auxiliary supply power, by the supercapacitor group or the associated current falls below the predetermined current limit value, the signal is again present at the gate terminal of the field-effect transistor and the external device can be actuated.

[0014] In principle, various switches can be used. According to a preferred embodiment of the invention, however, the switch is a flip-flop switch, wherein the flip-flop switch has a set terminal, a reset terminal and an output terminal, wherein the output terminal of the flip-flop switch is connected to the gate terminal of the field-effect transistor for signal transmission, wherein a signal is supplied at the set terminal of the flip-flop switch in the backup operating state, such that the field-effect transistor is switched through, the current limiter is connected to the reset terminal for signal transmission, and the current limiter is configured for triggering the reset terminal at the predetermined current limit value, such that the galvanically conductive connection between the supercapacitor group and the external device is interrupted.

[0015] A set / reset flip-flop switch has the advantage that a memory function is realized with it. It is a type of bistable multivibrator, which means that it has two stable states between which it can switch and remain in each of these states until it is changed by a control signal. A set / reset flip-flop has two input terminals receiving the following inputs: the set input (S) and the reset input (R). The states of the flip-flop change according to the input signals. If the set signal is active (normally a logic "1" signal), the flip-flop is triggered to the "set" state, whereby the output is set to "1". If the reset signal is active (normally a logic "1" signal), the flip-flop is triggered to the "reset" state, with the output set to "0". If both the set and reset signals are active / triggered at the same time, the output of the flip-flop remains "0". If the reset terminal of the flip-flop switch is triggered with the current limiter, no signal is present at the gate until the trigger at the reset terminal is terminated by the current limiter. This means that if a trigger occurs at the set terminal even though the supercapacitor group is still losing charge, the field-effect transistor remains closed and the galvanically conductive connection between the supercapacitor and the external device is interrupted.

[0016] In principle, it is possible for the supercapacitor group to have a continuous galvanic conductive connection with the current limiter. According to a preferred embodiment of the invention, however, the electronically controlled door latch arrangement comprises a further field-effect transistor, wherein a source terminal of the further field-effect transistor is galvanically conductively connected to the supercapacitor group, a drain terminal of the further field-effect transistor is galvanically connected to the current limiter, and a gate terminal of the further field-effect transistor is connected to the main power source of the vehicle in such a way that the further field-effect transistor is switched through in the backup operating state. In the present case, "connected to the main power source in such a way that the further field-effect transistor is switched through in the backup operating state" means that the gate connection is connected to the main power source in such a way that a change to the backup operating state or a failure of the normal operating state leads to a signal being applied to the gate of the further field-effect transistor, as a result of which it is switched through and the supercapacitor group can supply the external device with auxiliary supply power.

[0017] It is possible to trigger the set terminal of the flip-flop switch in different ways. According to a preferred embodiment of the invention, however, the electronically controlled door latch arrangement further comprises a control unit, wherein the control unit is configured for triggering the set terminal of the flip-flop switch in the backup operating state. According to a preferred further development of the invention, the control unit is a microcontroller.

[0018] It is particularly preferred in this context according to a further embodiment of the invention, that the control unit is connected to the gate terminal of the further field-effect transistor for signal transmission, and the control unit is configured for through-switching the further field-effect transistor in the backup operating state. The supercapacitor group is then galvanically connected to the current limiter only if the main supply power fails. This protects the supercapacitor group, as it undergoes fewer charging and discharging cycles.

[0019] According to a preferred embodiment of the invention, the control unit is configured to trigger the set terminal of the flip-flop switch when the galvanically conductive connection between the supercapacitor group and the external device is interrupted, the control unit being further configured to output an error when the flip-flop switch is repeatedly triggered at the reset terminal by the current limiter. Usually, the control unit is switched off in the backup operating state because it requires too much power to stay alive. According to the embodiment of the invention, however, it is provided that the control unit is switched on to trigger the flip-flop switch in at the set terminal so that the supercapacitor group can supply the external device with auxiliary supply power.

[0020] The invention further concerns the use of the electronically controlled door latch arrangement, as described above, on a door of the vehicle.

[0021] The invention concerns also a vehicle comprising the electronically controlled door latch arrangement according, as described above, and the main power source, wherein the main power source is connected to the control unit such that the control unit can trigger the set terminal of the flip-flop switch and the further field-effect transistor in the backup operating state. The control unit therefore detects the failure of the main supply power and switches the other field effect transistor through.

[0022] The invention also relates to a method for operating an electronically controlled door latch arrangement of a vehicle, the arrangement comprising an external device, a supercapacitor group and a current limiter, wherein the supercapacitor group is galvanically conductively connected to the external device via the interconnected current limiter, the supercapacitor group is chargeable with a main supply power provided by a main power source of the vehicle during a normal operating state, such that in the event of a unavailability of the main supply power, an auxiliary supply power is provided to the external device employing the supercapacitor group during a backup operating state, and comprising the step of: interrupting a current to the external device from the supercapacitor group, immediately when the current limiter registers the predetermined current limit value.

[0023] According to a preferred embodiment of the invention the step of interrupting the current is only executed in the backup operating state, where no main supply power from the main power source is available.

[0024] According to a further preferred embodiment of the invention, the method for operating an electronically controlled door latch arrangement of a vehicle comprises the following additional steps: attempt to reconnect the supercapacitor group to the external device after the connection has been interrupted, and output of an error if the connection was interrupted again after repeated attempts.

[0025] Further implementations and advantages of the method can be derived by the person skilled in the art from the electronically actuated door latch as described before.Brief description of drawings

[0026] These and other aspects of the invention will be apparent from and elucidated with reference to the implementation described hereinafter.

[0027] In the drawings: Fig. 1schematically depicts an electronically controlled door latch arrangement and a main power source according to a preferred embodiment of the invention, and Fig. 2schematically depicts a vehicle comprising the electronically controlled door latch arrangement and the main power source according to a preferred embodiment of the invention. Description of implementations

[0028] Fig. 1 schematically depicts an electronically controlled door latch arrangement 1 according to a preferred embodiment of the invention. The electronically controlled door latch arrangement 1 for a vehicle 17 shown in Fig. 2 has an external device 2 which is connected to a drain terminal 9 of a field-effect transistor 7. In this case, the external device 2 is an electronically actuated door handle on a door 16 of the vehicle 17. A source terminal 8 of this field-effect transistor 7 is galvanically connected to a current limiter 4. The current limiter 4 is in turn galvanically connected to a gate terminal 8 of a further field-effect transistor 15. A supercapacitor group 3 is connected with an intermediate voltage regulator 18 to a source terminal 8 of the other field-effect transistor 15. A main power source 5, which in this case is designed as the vehicle battery of the vehicle 17 in Fig. 2, is connected to a control unit 14 and a gate terminal 10 of the further field-effect transistor 15 for signal transmission. If the main power source 5 of vehicle 17 fails, the electronically controlled door latch arrangement 1 switches from a normal operating state to a backup operating state. A signal is present at the gate terminal 10 of the additional field-effect transistor 15, so that it switches through and the supercapacitor group 3 provides the external device 2 with an auxiliary supply power.

[0029] This is made possible by the control unit 14 actuating a set terminal 11 of a flip-flop switch 6 and this switch 6 thus emitting a corresponding signal at its output terminal 13, which in turn is present at a gate terminal 10 of the field-effect transistor 7, which thus switches through. If the current limiter 4 now detects a current from the supercapacitor group 3 that is above a predetermined current value limit, the current limiter 4 emits a signal to a reset terminal 12 of the flip-flop switch 6, as a result of which no more signal is emitted from the output terminal 13, such that the field-effect transistor 7 accordingly interrupts the galvanically conductive connection between the current limiter 4 and the external device 2 and the charge in the supercapacitor group 3 is maintained.

[0030] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed implementations. Other variations to be disclosed implementations can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting scope.List of reference symbols

[0031] 1electronically controlled door latch arrangement 2external device 3supercapacitor group 4current limiter 5main power source 6switch / flip-flop switch 7field-effect transistor 8source terminal 9drain terminal 10gate terminal 11set terminal 12reset terminal 13output terminal 14control unit 15further field-effect transistor 16door 17vehicle 18voltage regulator

Claims

1. Electronically controlled door latch arrangement (1) for a vehicle (17), the arrangement comprising an external device (2), a supercapacitor group (3) and a current limiter (4), wherein the supercapacitor group (3) is galvanically conductively connected to the external device (2) via the interconnected current limiter (4), the supercapacitor group (3) is chargeable with a main supply power provided by a main power source (5) of the vehicle (17) during a normal operating state, such that in the event of an unavailability of the main supply power, an auxiliary supply power is provided to the external device (2) employing the supercapacitor group (3) during a backup operating state, and the current limiter (4) is configured to interrupt a current to the external device (2) from the supercapacitor group (3) at a predetermined current limit value, such that the charge in the supercapacitor group (3) is maintained.

2. Electronically controlled door latch arrangement (1) according to the previous claim, wherein the predetermined current limit value corresponds to the auxiliary supply power from the supercapacitor group (3).

3. Electronically controlled door latch arrangement (1) according to any one of the previous claims, wherein the current limiter (4) is configured for interrupting the current only in the backup operating state.

4. Electronically controlled door latch arrangement (1) according to any one of the previous claims with a switch (6) galvanically conductively connected between the current limiter (4) and the external device (2), wherein the current limiter (4) is connected to the switch (6) for signal transmission, such that the switch (6) interrupts the galvanically conductive connection between the supercapacitor group (3) and the external device (2) in response to a signal or the absence of a signal from the current limiter (4) at the predetermined current limit value.

5. Electronically controlled door latch arrangement (1) according to any one of the previous claims with a galvanically connected field-effect transistor (7) between the current limiter (4) and the external device (2), wherein a source terminal (8) of the field-effect transistor (7) is galvanically conductively connected to the current limiter (4), wherein a drain terminal (9) of the field-effect transistor (7) is galvanically conductively connected to the external device (2), wherein the current limiter (4) is connected to a gate terminal (10) of the field-effect transistor (7) for transmitting the signal, wherein the current limiter (4) is configured for transmitting a signal when the current is below the predetermined current limit value, such that the field-effect transistor (7) is switched through, and the current limiter (4) is further configured for terminating the signal transmission at the predetermined current limit value, such that the galvanically conductive connection between the supercapacitor group (3) and the external device (2) is interrupted.

6. Electronically controlled door latch arrangement (1) according to the previous claim with a flip-flop switch (6), wherein the flip-flop switch (6) has a set terminal (11), a reset terminal (12) and an output terminal (13), wherein the output terminal (13) of the flip-flop switch (6) is connected to the gate terminal (10) of the field-effect transistor (7) for signal transmission, wherein a signal is supplied at the set terminal (11) of the flip-flop switch (7) in the backup operating state, such that the field-effect transistor (7) is switched through, the current limiter (4) is connected to the reset terminal (12) for signal transmission, and the current limiter (4) is configured for triggering the reset terminal (12) at the predetermined current limit value, such that the galvanically conductive connection between the supercapacitor group (3) and the external device (2) is interrupted.

7. Electronically controlled door latch arrangement (1) according to any one of the previous claims with a further field-effect transistor (15), wherein a source terminal (8) of the further field-effect transistor (15) is galvanically conductively connected to the supercapacitor group (3), a drain terminal (9) of the further field-effect transistor (15) is galvanically connected to the current limiter (4), and a gate terminal (10) of the further field-effect transistor (15) is connected to the main power source (5) of the vehicle (17) in such a way that the further field-effect transistor (15) is switched through in the backup operating state.

8. Electronically controlled door latch arrangement (1) according to any one of the claims 6 or 7 with a control unit (14), wherein the control unit (14) is configured for triggering the set terminal (11) of the flip-flop switch (6) in the backup operating state.

9. Electronically controlled door latch arrangement (1) according to the previous claim, wherein the control unit (14) is connected to the gate terminal (10) of the further field-effect transistor (15) for signal transmission, and the control unit (14) is configured for through-switching the further field-effect transistor (15) in the backup operating state.

10. Electronically controlled door latch arrangement (1) according to any one of the claims 8 or 9, wherein the control unit (14) is configured to trigger the set terminal (11) of the flip-flop switch (6) when the galvanically conductive connection between the supercapacitor group (3) and the external device (2) is interrupted, the control unit (14) being further configured to output an error when the flip-flop switch (6) is repeatedly triggered at the reset terminal (12) by the current limiter (4).

11. Use of the electronically controlled door latch arrangement (1) according to one of the preceding claims on a door (16) of the vehicle (17).

12. Vehicle (17) comprising the electronically controlled door latch arrangement (1) according to any one of the claims 7 to 10, and the main power source (5), wherein the main power source (5) is connected to the control unit (14) such that the control unit (14) can trigger the set terminal (11) of the flip-flop switch (6) and the further field-effect transistor (17) in the backup operating state.

13. Method for operating an electronically controlled door latch arrangement (1) of a vehicle (17), the arrangement comprising an external device (2), a supercapacitor group (3) and a current limiter (4), wherein the supercapacitor group (3) is galvanically conductively connected to the external device (2) via the interconnected current limiter (4), the supercapacitor group (3) is chargeable with a main supply power provided by a main power source (5) of the vehicle (17) during a normal operating state, such that in the event of a unavailability of the main supply power, an auxiliary supply power is provided to the external device (2) employing the supercapacitor group (3) during a backup operating state, and comprising the step of: interruption of a current to the external device (2) from the supercapacitor group (3), immediately when the current limiter (4) registers the predetermined current limit value.

14. Method according to the previous claim, wherein the step of interrupting the current is only executed in the backup operating state, where no main supply power from the main power source (5) is available.

15. Method according to any one of the claims 13 or 14, comprising the following additional steps: attempt to reconnect the supercapacitor group (3) to the external device (2) after the connection has been interrupted, and output of an error if the connection was interrupted again after repeated attempts.

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