How to diagnose automotive latches and automotive latch switches

Abstract

The present invention relates to an automotive latch (1) for locking the door (3) of an automobile (2), comprising a diagnostic switch (4) and a diagnostic circuit (5), wherein the diagnostic switch (4) is The diagnostic circuit (5) comprises a parallel resistor (6), a switch (7) configured to determine the position of the door (3), and a series resistor (8), wherein the parallel resistor (6) is connected in parallel with the switch (7) and in series with the series resistor (8). The diagnostic circuit (5) comprises a diode (10), a pull-up resistor (11) configured to receive a pull-up voltage from a power supply (16), a voltage divider (12) having a midpoint (13), and a microcontroller (14), wherein the diode (10) is connected between the series resistor (8) and the voltage divider (12), the midpoint (13) is connected to the microcontroller (14), the anode of the diode (10) facing the voltage divider (12) is connected to the pull-up resistor (11), and the microcontroller (14) is configured to determine whether the midpoint voltage of the midpoint (13) correlates with the switching position of the switch (7).

Description

Technical Field

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[0001] The present invention relates to an automotive latch for locking a vehicle door, and includes a diagnosable switch having a parallel resistor, a switch configured to determine the position of the door, and a series resistor. The parallel resistor is connected in parallel with the switch and in series with the series resistor. The present invention further relates to a method for diagnosing a switch of an automotive latch for locking a vehicle door, the automotive latch including a diagnosable switch having a parallel resistor, a switch configured to determine the position of the door, and a series resistor, the parallel resistor being connected in parallel with the switch and in series with the series resistor.

Background Art

[0002] Switches are commonly used in automotive latch applications to sense position for specific applications. Commonly used positions are "primary" to identify that the vehicle door is closed, "open" to identify that the vehicle door is open, and "secondary" to identify an intermediate position close to "primary".

[0003] For this type of switch, due to safety requirements, in both normal operation mode and power-saving mode, in order to provide continuous diagnosis, in-depth diagnosis by special circuits and methods is required.

[0004] Regarding circuits, for example, a diagnosable switch having parallel and series resistors inside is often used. However, the circuits and their respective methods known in the prior art often do not meet safety requirements, especially regarding the power-saving mode.

Summary of the Invention

[0005] Therefore, an object of the present invention is to provide an easy, inexpensive and / or highly reliable solution for improving the diagnosis of switches in automotive latches.

[0006] The object of the present invention is resolved by the features of the independent claim. Preferred embodiments are described in detail in the dependent claims.

[0007] Therefore, the objective is achieved by an automotive latch for locking a car door, the automotive latch comprising a diagnostic switch and a diagnostic circuit, the diagnostic switch comprising a parallel resistor, a switch configured to determine the position of the door, and a series resistor, the parallel resistor connected in parallel with the switch and connected in series with the series resistor, further comprising a diode, a pull-up resistor configured to receive a pull-up voltage from a power supply, a voltage divider having a midpoint, and a microcontroller, the diode connected between the series resistor and the voltage divider, the midpoint connected to the microcontroller, the anode of the diode facing the voltage divider connected to the pull-up resistor, and the microcontroller configured to determine whether the midpoint voltage of the midpoint correlates with the switching position of the switch.

[0008] The proposed automotive latch and the corresponding method described below provide a simple and reliable solution for continuously diagnosing switches, both during normal operation and in power-saving mode, particularly for performing diagnostic routines on switches, diagnostic switches, and / or automotive latches. The proposed diagnostic circuit makes it possible to detect open load, battery short, and ground short faults in the switch, i.e., the diagnostic switch. For example, while open, a diode isolates the diagnostic circuit from the diagnostic switch, and a pull-up voltage allows connection of external devices such as advanced driver-assistance systems (ADAS) devices.

[0009] The power source may be the vehicle's main power supply, preferably provided as a vehicle battery supplying 12V or 24V DC, for example. The automotive latch preferably comprises an electric motor configured to actuate the automotive latch with respect to locking and unlocking the doors of the vehicle. More generally, the expression “automotive latch” should be understood as a means of locking a movable element between an open position and a closed position, thereby opening and closing access to the interior compartments of the vehicle, which may include, for example, the trunk, rear hatch, hood lid and other closed compartments, window regulators, sunroofs, etc., in addition to the side doors.

[0010] The vehicle may be provided as an electric vehicle. The automotive latch may comprise a housing made of metal, resin, or a combination thereof. In particular, the electric motor, a diagnostic switch, and a diagnostic circuit are preferably housed within the housing. Furthermore, the diagnostic switch and the diagnostic circuit may be housed within a separate electronic housing and / or within the automotive latch, which is located within the housing.

[0011] According to a preferred embodiment, the microcontroller is provided as a system basic chip (SBC), as a microprocessor, and / or as part of an automotive latch and / or automotive electronic control unit (ECU). The system basic chip is preferably provided as an integrated circuit that includes various functions of the automotive electronic control unit (ECU) on a single die. The system basic chip and / or microcontroller may include embedded functions such as a voltage regulator, monitoring functions, a reset generator, a watchdog function, a local interconnect network (LIN), a CAN bus or other bus interface, wake-up logic, and / or a power switch. The microcontroller preferably includes analog input peripherals such as an analog-to-digital converter (ADC) and is connected to a midpoint. The term “connected” should be understood to preferably mean electrically connected.

[0012] A switch, i.e., a diagnostic switch, is preferably connected to the door operationally and / or mechanically to determine the door's position. The position may be, for example, closed ("primary"), open ("open"), and / or an intermediate position close to the closed position ("intermediate"). A diode may be provided as any diode known in the prior art that allows current to flow primarily in one direction. A pull-up resistor is preferably connected to the power supply. The diode is preferably connected with its cathode to one end of a series resistor and the other end of the series resistor to a parallel resistor. Determining whether the midpoint voltage correlates with the switch's switching position means, in particular, confirming whether the switching position matches each and / or estimated voltage of the midpoint voltage. For example, if the midpoint voltage is 0, there is a fault (e.g., a ground short circuit); if the midpoint voltage is equal to the power supply voltage, there is also a fault (e.g., a power supply short circuit); if the midpoint voltage is close to the low threshold (e.g., 1V), the determined location is valid; if the midpoint voltage is close to the high threshold (e.g., 3V), the determined location is valid; and if the midpoint voltage is close to the open-circuit load voltage threshold (e.g., 2V), there is also a fault.

[0013] According to a preferred embodiment, the parallel resistors, switches, and / or voltage dividers are connected, in particular, with one end connected to ground. Preferably, the other ends of the switches and parallel resistors are connected to each other. The voltage divider preferably comprises two resistors connected in series, with the midpoint located at the connection point of these two resistors.

[0014] In another preferred embodiment, an automotive latch, particularly a diagnostic circuit, includes a filter capacitor, which is connected to a midpoint and preferably also to ground. Specifically, the filter capacitor has one end connected to the midpoint and the other end connected to ground. The filter capacitor is preferably configured to filter low-frequency components.

[0015] According to another preferred embodiment, an automotive latch, particularly a diagnostic circuit, comprises a pull-up switch connected to one end of a pull-up resistor and configured to receive a pull-up voltage from a power supply, and a microcontroller is configured to toggle the pull-up switch. The pull-up switch may be provided as an electronic switch, such as a transistor or a MOSFET.

[0016] In another preferred embodiment, the microcontroller is configured to determine whether the midpoint pull-up voltage correlates with the switch's switching position, particularly only when the pull-up switch is switched on. Preferably, the voltages that the pull-up resistor can receive are switched by a microprocessor using a polling pulse scheme, for example, by a pulse with a very low duty cycle. In this regard, the microcontroller preferably reads the midpoint voltage only when the pulse is active. The midpoint voltage is preferably checked against the switching state before any operation relating to the door position is initiated.

[0017] In another preferred embodiment, the microprocessor is configured to periodically and / or continuously switch the voltage that the pull-up resistor can receive. Preferably, the microprocessor is configured to periodically and / or continuously determine whether the midpoint voltage of the midpoint is correlated with the switching position of the switch.

[0018] In another preferred embodiment, the microcontroller is configured to emit a fault signal if the midpoint voltage does not correlate with the switching position. When such a fault related to the fault signal is detected, the microcontroller can notify the bus interface of the fault, for example, via a CAN or LIN interface, thereby allowing internal and / or external safety operations to be evaluated and a dangerous condition to be avoided. Alternatively or additionally, the fault signal may be emitted to the vehicle's electronic control unit (ECU).

[0019] According to another preferred embodiment, the microcontroller has a power-saving mode with a corresponding wake-up function, configured to determine whether the midpoint voltage of the midpoint is correlated with the switch's toggle position after waking from sleep. During such a power-saving mode, the energy consumption of the microcontroller is reduced compared to the normal operating mode, for example, by 50%, 70%, 90%, or 100%. The wake-up function may be triggered by an inner handle trigger, in addition to other factors. In such a case, when operation is required, the proposed diagnostic routine is executed, and only safe operations may be performed. The diagnostic routine may be re-executed before the microcontroller enters the power-saving mode. This avoids additional power consumption due to periodic wake-ups solely for diagnostic purposes, because during power-saving mode, the vehicle battery may be lost and / or other bus devices may not be able to operate on the main bus interface, for example, via the CAN and / or LIN buses.

[0020] Furthermore, the objective can also be achieved by a vehicle equipped with the aforementioned automotive latch and a battery as a power source.

[0021] Furthermore, the objective can also be achieved by a method for diagnosing a switch of an automotive latch for locking a car door, the automotive latch comprising a diagnosable switch and a diagnostic circuit, the diagnosable switch comprising a parallel resistor, a switch configured to determine the position of the door, and a series resistor, the parallel resistor connected in parallel with the switch and connected in series with the series resistor, the diagnostic circuit comprising a diode, a pull-up resistor configured to receive a pull-up voltage from a power supply, and a voltage divider having a midpoint, the diode connected between the series resistor and the voltage divider, the anode of the diode facing the voltage divider connected to the pull-up resistor, the method comprising the step of determining whether the midpoint voltage of the midpoint correlates with the switching position of the switch.

[0022] According to a preferred embodiment, the automotive latch includes a pull-up switch configured to be connected to a pull-up resistor and receive a pull-up voltage from a power source, and the method includes a step of switching the pull-up switch.

[0023] In another preferred embodiment, the method includes a step of determining whether the midpoint voltage at the midpoint correlates with the switching position of the switch when the pull-up switch is switched on.

[0024] According to yet another preferred embodiment, the method includes a step of at least periodically or continuously switching the voltage that the pull-up resistor can receive.

[0025] In another preferred embodiment, the method includes a step of emitting a fault signal when the midpoint voltage does not correlate with the switching position.

[0026] According to yet another preferred embodiment, particularly the diagnostic circuit includes a microprocessor connected to the midpoint, the microcontroller includes a power-saving mode having respective wake-up functions, and the method includes a step of determining whether the midpoint voltage at the midpoint correlates with the switching position of the switch after waking up the microprocessor.

[0027] Those skilled in the art can derive further embodiments and advantages of the method from the vehicle door latch as described above.

Brief Description of the Drawings

[0028] These and other aspects of the present invention will become apparent and be described by referring to the embodiments described below. [Figure 1] FIG. 1 shows a schematic of a circuit diagram including a diagnosable switch and a diagnostic circuit of an automotive latch according to a preferred embodiment.

[0029] Description of the Embodiment

[0030] Figure 1 shows a schematic circuit diagram of a similarly schematic-only automotive latch 1 for locking the doors of a schematic-only automobile 2. The automobile 2 includes four side doors, one of which door 3 is schematicly shown in Figure 1, and each door is equipped with one automotive latch 1. Furthermore, the automotive latch 1 can be associated not only with the side doors 3 of such an automobile 2, but also with the rear hatch, hood lid and other closed compartments, window regulators, and sunroof.

[0031] The automotive latch 1 comprises a housing made of resin, metal, or a combination thereof. Within this housing, a diagnostic switch 4 and a diagnostic circuit 5 are located in a separate electronic housing (not shown).

[0032] The diagnostic switch 4 comprises a parallel resistor 6, a switch 7 configured to determine the position of door 3, and a series resistor 8. The parallel resistor 6 and switch 7 are connected in parallel to each other, with one end connected to ground 9. The other end is connected to the series resistor 8, thereby connecting the parallel resistor 6 and the series resistor 8 in parallel. Switch 7 is provided as a mechanical switch operationally connected to door 3.

[0033] The diagnostic circuit 5 comprises a diode 10, a pull-up resistor 11, a voltage divider 12 with a midpoint 13, a microcontroller 14, and optionally a filter capacitor 15. The diode 10 is connected such that its cathode is connected to the other end of a series resistor 8, and the series resistor 8 is connected between the cathode and a parallel resistor 6. The anode of the diode 10 is connected to the pull-up resistor 11 and one end of the voltage divider 12.

[0034] The voltage divider 12 comprises two resistors connected in series, thereby forming a midpoint 13 between the two resistors. The other end of the voltage divider 12 is connected to ground 9. The filter capacitor 15 is connected in parallel between the midpoint 13 and ground 9, i.e., to one of the two resistors of the voltage divider 12. The microcontroller 14 comprises an analog input peripheral such as an analog-to-digital converter (ADC), the input of which is connected to the midpoint 13.

[0035] Automobile 2 is provided as a standard on-board battery known in the prior art and includes a mains power supply 16 that delivers a 12V DC mains power supply voltage. The mains power supply voltage is supplied to the other end of a pull-up resistor 11 via a pull-up switch 17. The electronically provided pull-up switch 17 is switched by a microcontroller 14, particularly via the digital-to-analog converter output of the microcontroller 14.

[0036] Such a diagnostic circuit 5 makes it possible to detect faults such as open load, battery short circuit (i.e., short circuit to mains power supply 16), and short circuit to ground 9. Therefore, the diode 10 isolates the diagnostic circuit 5 when switch 7 is open, and allows connection of external devices. During the test routine operation, the main supply voltage of mains power supply 16 is supplied to the voltage-controlled pull-up resistor 11 via the pull-up switch 17 operated by the microcontroller 14, and then to the midpoint 13. The microcontroller 14 can thus determine whether the midpoint voltage of the midpoint 13 correlates with the switching position of switch 7.

[0037] The voltage supplied from the pull-up switch 17 to the pull-up resistor 11 is periodically controlled by the microcontroller 14 according to a polling pulse scheme. When the pulse is active, the microcontroller 14 reads an analog value from the midpoint 13 and determines whether that value is acceptable before performing any action, such as checking the state of switch 7 to the control unit of the automobile 2. Thus, the microcontroller 14 is provided as an SBC (System Basic Chip).

[0038] During the normal operation mode of door 3, diagnostics by the diagnostic switch 4 and diagnostic circuit 5 are continuous. If a fault is detected in switch 7, the fault is notified, for example, on the bus interface of the microcontroller 14 provided as CAN or LIN, thereby evaluating the internal safety operation of the vehicle 2 and preventing dangerous conditions for the vehicle 2 and door 3.

[0039] The microcontroller 14 has a power-saving mode with a corresponding wake-up function, which, after waking from sleep, determines whether the midpoint voltage of the midpoint 13 correlates with the switching position of the switch 7. During such a power-saving mode, it is desirable to reduce power consumption. Therefore, the diagnostic routine is executed when an operation is required, for example, an inner handle trigger. In such cases, only safe operations are performed, and before that, the microcontroller 14 is put into the power-saving mode to re-execute the diagnostic routine. This method avoids additional power consumption due to periodic wake-ups solely for diagnostic purposes, because during power saving mode, the main power supply 16 is lost and other bus devices cannot be operated on the bus interface.

[0040] Although the present invention is illustrated and described in detail in the drawings and the foregoing description, these illustrations and descriptions are illustrative and should not be constrained to be limited, and the present invention is not limited to the disclosed embodiments. Other variations can be understood and achieved in the practice of the present invention by examining the drawings, disclosure and the appended claims, by those skilled in the art. In the claims, the term “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude the plural. The mere fact that certain means are described in different dependent claims does not suggest that combinations of these means cannot be used advantageously. The reference numerals in the claims should not be constrained to limit the scope of rights. [Explanation of Symbols]

[0041] 1…Automotive latch, 2…Automobiles, 3... Door, 4…Diagnosable switches, 5…Diagnostic circuit, 6...Parallel resistance, 7... Switch, 8…Series resistor, 9... Ground, 10... Diode, 11... Pull-up resistor, 12...Voltage divider, 13...midpoint, 14… Microcontroller, 15…Filter capacitor, 16...Power supply, 17... Pull-up switch.

Claims

1. An automotive latch (1) for locking the door (3) of a car (2), comprising a diagnostic switch (4) and a diagnostic circuit (5), The diagnostic switch (4) comprises a parallel resistor (6), a switch (7) configured to determine the position of the door (3), and a series resistor (8), wherein the parallel resistor (6) is connected in parallel with the switch (7) and in series with the series resistor (8), The diagnostic circuit (5) comprises a diode (10), a pull-up resistor (11) configured to receive a pull-up voltage from a power supply (16), a voltage divider (12) having a midpoint (13), and a microcontroller (14), wherein the diode (10) is connected between the series resistor (8) and the voltage divider (12), the midpoint (13) is connected to the microcontroller (14), the anode of the diode (10) facing the voltage divider (12) is connected to the pull-up resistor (11), and the microcontroller (14) is configured to determine whether the midpoint voltage of the midpoint (13) correlates with the switching position of the switch (7), in the automotive latch (1).

2. The automotive latch (1) according to claim 1, wherein the switch (7), the parallel resistor (6), and the voltage divider (12) are connected to ground (9).

3. The automotive latch (1) according to claim 1, comprising a filter capacitor (15) connected to the midpoint (13) and preferably also connected to ground (9).

4. The automotive latch (1) according to claim 1, further comprising a pull-up switch (17) connected to the pull-up resistor (11) and configured to receive a pull-up voltage from the power supply (16), wherein the microcontroller (14) is configured to switch the pull-up switch (17).

5. The automotive latch (1) according to claim 4, wherein when the pull-up switch (17) is switched on, the microcontroller (14) is configured to determine whether the pull-up voltage of the midpoint (13) correlates with the switching position of the switch (7).

6. The automotive latch (1) according to claim 1, wherein the microcontroller (14) is configured to switch at least periodically or continuously the voltage that the pull-up resistor (11) can receive.

7. The automotive latch (1) according to claim 1, wherein the microcontroller (14) is configured to output a fault signal if the midpoint voltage does not correlate with the switching position.

8. The automotive latch (1) according to claim 1, wherein the microcontroller (14) is provided with a power-saving mode having a corresponding wake-up function and is configured to determine whether the midpoint voltage of the midpoint (13) correlates with the switching position of the switch (7) after waking up.

9. An automobile (2) comprising an automobile latch (1) as described in claim 1 and a battery as a power source (16).

10. A method for diagnosing the switch (7) of an automotive latch (1) for locking the door (3) of an automobile (2), The automotive latch (1) includes a diagnostic switch (4) and a diagnostic circuit (5), The diagnostic switch (4) comprises a parallel resistor (6), a switch (7) configured to determine the position of the door (3), and a series resistor (8), wherein the parallel resistor (6) is connected in parallel with the switch (7) and in series with the series resistor (8), The diagnostic circuit comprises a diode (10), a pull-up resistor (11) configured to receive a pull-up voltage from a power supply (16), and a voltage divider (12) having a midpoint (13). The diode (10) is connected between the series resistor (8) and the voltage divider (12), and the anode of the diode (10) facing the voltage divider (12) is connected to the pull-up resistor (11). The method is as follows: A method comprising the step of determining whether the midpoint voltage of the midpoint (13) correlates with the switching position of the switch (7).

11. The automotive latch (1) is equipped with a pull-up switch (17), the pull-up switch (17) is connected to the pull-up resistor (11) and is configured to receive a pull-up voltage from the power supply (16), and the method is as follows: The method according to claim 10, further comprising the step of switching the pull-up switch (17).

12. The method according to claim 10, further comprising the step of determining whether the midpoint voltage of the midpoint (13) correlates with the switching position of the switch (7) when the pull-up switch (17) is switched on.

13. The method according to claim 10, further comprising the step of switching at least periodically or continuously the voltage that the pull-up resistor (11) can receive.

14. The method according to claim 10, further comprising the step of generating a fault signal if the midpoint voltage does not correlate with the switching position.

15. The method according to claim 10, further comprising a microcontroller (14) connected to the midpoint (13), wherein the microcontroller (14) has a power-saving mode having a wake-up function, and the method includes the step of determining whether the midpoint voltage of the midpoint (13) corresponds to the switching position of the switch (7) after waking the microcontroller (14) from sleep.

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