Method for monitoring short-circuit switching processes of a control device circuit

Abstract

The present invention relates to a method for monitoring short-circuit switching processes of a circuit (120), particularly an output terminal circuit (120) of a control device (100), wherein information regarding the control device (100) is detected, and whether a short-circuit switching process exists and whether the circuit (120) executes a switching-on process during the short circuit is evaluated, and if it is recognized that a short-circuit switching process exists during the evaluation process, a counter reading characterizing the number of short-circuit switching processes executed over the lifespan of the circuit (120) is updated.

Description

Technology Field

[0001] The present invention relates particularly to a method for monitoring short-circuit switching processes of a circuit of a control device in a vehicle, and a computing unit for executing the same. Background Technology

[0002] For example, output terminals or output terminal circuits within control units in a vehicle (automobile) represent the final electronic stage of a power amplifier before the amplified signal is applied to a load. In this way, output terminal circuits may be provided, for example, within an engine control unit to provide the output necessary to control actuators. Within the control unit, each output terminal circuit may be controlled by a microcontroller using corresponding control signals.

[0003] In order to ensure the (operational) safety of the control device, output stage circuits are generally formed to be robust enough to withstand at least a predetermined minimum number of switching (on) cycles in the event of a short circuit, that is, in the event of a short circuit to the battery or ground. However, if too many of these types of short-circuit switching cycles are executed, particularly in PWM control, damage or even destruction of the output stage and, consequently, the entire control device may occur. <Prior Art> 1. U.S. Patent Publication US 2012 / 0249155 A1 (Oct. 4, 2012) 2. PCT Publication WO 2006 / 059646 A1 (June 8, 2006)

[0004] Against this backdrop, a method for monitoring short-circuit switching processes of a circuit of a control device having the features of independent claims, and a computing unit for implementing the same are proposed. Preferred embodiments are the subject of dependent claims and the following detailed description.

[0005] In the course of this method, current information regarding the control device is detected, and whether a short-circuit switching process exists—that is, whether the circuit executes the switching-on process during a short circuit (i.e., without a load)—is evaluated. If, during the evaluation process, it is recognized that a short-circuit switching process exists, a counter or counter reading characterizing or representing the number of short-circuit switching processes executed over the circuit's lifetime is updated or incremented.

[0006] Through the detection and evaluation of control device information, it is preferably possible to recognize whether a current short-circuit switching process is occurring during the operation of the control device. Accordingly, the counter reading is continuously updated over its lifespan when a new short-circuit switching process is recognized.

[0007] Based on the counter reading, measures to protect the output circuit or eliminate errors can be executed, for example. Additionally, the counter reading allows for inference, for example, regarding the high risk of damage or destruction to the output. Furthermore, for example, if the counter reading is very high and approaches a predetermined number of allowed switching (on) cycles, for instance, in the event of a short circuit, the operation of the output may be limited or affected.

[0008] Counter readings can preferably be read at a repair shop to facilitate, for example, error detection or repairs. Additionally, if the output stage or control unit is damaged or destroyed, counter readings can be useful for subsequent cause detection. Particularly preferably, counter readings can be used to verify whether a warranty claim is valid. For example, counter readings can be used to determine whether the (end) customer ignored warning messages, such as an activated engine check light, over a longer period, which may result in a reduction or exclusion of warranty service through the (control unit) manufacturer.

[0009] Information regarding the control unit characterizes, in particular, the current operation of the control unit, the current signals of the control unit for controlling the output circuit, and in particular, the current errors or error messages of the control unit. From this information, it is particularly desirable to infer whether the circuit is currently being controlled and whether a short circuit exists within the control unit. For example, different measures for detecting a short circuit within the output of a vehicle control unit are known and, in part, specified. For example, detected measurements may be evaluated. For example, it may be checked whether the current passing through the output circuit exceeds an allowable limit. Additionally, for example, the diagnostic function of the control unit or error diagnosis for recognizing an error state may be used.

[0010] Preferably, based on the counter reading or the current value of the counter reading, the priority of short-circuit switching processes that are executed, should be executed, or can be executed during a predetermined diagnostic interval, particularly during the current diagnostic interval. For example, each of these individual diagnostic intervals may correspond to the driving cycle of a vehicle (automobile). Preferably, the short-circuit switching processes executed during the process of error diagnosis or error recognition are prioritized. In particular, through this type of switching process for error diagnosis, it may be checked or recognized whether a short circuit still exists or whether the control unit functions flawlessly without a short circuit again after healing. Through this priority determination, the frequency at which the presence of a short circuit is checked per diagnostic interval may preferably be set or predetermined. The higher the assigned priority, the more frequently error diagnosis is executed per diagnostic interval. In particular, as the lifespan of the circuit increases accordingly, the number of error diagnoses executed per diagnostic interval may be gradually reduced to prevent multiple unnecessary short-circuit switching processes and damage or failure of the output circuit.

[0011] As such, for example, at a low counter reading, particularly one reflecting the start of the output stage's lifespan, error diagnosis or error recognition is prioritized higher than at higher counter readings during later stages of the output stage's lifespan, because the likelihood of a short circuit being healed or eliminated is higher at the start of the lifespan than near the end. For example, by assigning a high priority to low counter readings accordingly, the presence of a short circuit can be checked multiple times per diagnostic interval. At higher counter readings, by assigning a lower priority, fewer switching processes for fault diagnosis per diagnostic interval may be allowed, or switching processes may not be allowed at all, particularly to prevent unnecessary load or even faults on the output stage circuit. For example, if the counter reading is below a predetermined threshold, a higher or highest priority may be assigned to the switching process for fault diagnosis. As the counter reading approaches this threshold, a lower priority may be selected.

[0012] Conventionally, the number of short-circuit switching processes executed per diagnostic interval is limited to a fixed, predetermined maximum number, depending on, for example, the type of each output stage, the voltage supply, the system used, the configuration, the sensors used, the current ambient temperature, etc. Conventionally, when a short circuit is detected, an error report is executed, particularly through the activation of the engine check light, and the presence of the short circuit is checked through additional switching-on processes during the diagnostic interval at fixed, predetermined time intervals until the fixed, predetermined maximum number of short-circuit switching processes per diagnostic interval is reached. If the short circuit is not cleared by then, the corresponding function of the control unit is often collectively and permanently disabled for the remainder of the diagnostic interval. Even if the healing of the short circuit is executed within this diagnostic interval, it can no longer be verified, and the corresponding function remains disabled. Only in a subsequent diagnostic interval can the short circuit be checked again.

[0013] In contrast, the frequency at which errors are checked per diagnostic interval can be dynamically matched based on counter readings within the scope of this method, particularly on the lifetime. Since the likelihood of healing is higher at the beginning of the lifetime than in the long lifetime, the short circuit is checked more frequently so that a potential healing of the short circuit can be recognized and control unit functions are not unnecessarily disabled in bulk, even if the short circuit is likely no longer present. In the long lifetime, errors per diagnostic interval may be checked only rarely or not at all, because although the likelihood of healing is lower in this case, the risk of destruction of the output circuit increases.

[0014] Preferably, the number of short-circuit switching processes that are executed, should be executed, or can be executed during a diagnostic interval or a driving cycle, particularly during the current diagnostic interval or driving cycle, is limited according to a counter reading or the current value of the counter reading. As described above, in conventional methods, short-circuit switching processes for error diagnosis per diagnostic interval can often be collectively limited to a fixed static value. In contrast, through the introduction of a counter reading, the limit on the number of allowed short-circuit switching processes per diagnostic interval can be dynamically matched, particularly to the number of short-circuit switching processes already executed by the circuit during its lifetime, and can be executed dynamically over the life of the circuit.

[0015] According to a preferred embodiment, a counter reading or the current value of the counter reading is compared with a predetermined threshold. For example, such a threshold may be predetermined based on the minimum number of short-circuit switching processes that the output circuit must withstand at least during its lifetime. For example, the threshold may indicate an increasing risk of circuit damage as the number of short-circuit switching processes executed so far approaches this minimum number. When the threshold is reached or exceeded, additional switching-on processes may be prevented or prohibited. Preferably, based on the comparison of the current counter reading with the preset threshold, the priority of short-circuit switching processes is determined and / or the number of short-circuit switching processes is limited. In particular, a uniform static limit on switching processes per diagnostic interval is not executed, and preferably, depending on the current lifetime of the output circuit, which switching process is allowed or how many switching processes are allowed at the time of a short circuit may be dynamically matched.

[0016] In particular, as the threshold value described above, a maximum value for the number of short-circuit switching processes that can be executed during the diagnostic interval can be predetermined.

[0017] Particularly preferably, the threshold is predetermined based on the number of diagnostic intervals executed. Preferably, the threshold is dynamically matched according to the lifespan of the output circuit thus far.

[0018] Preferably, the threshold value, particularly for the current diagnostic interval, is predetermined based on the (e.g., linear or logarithmic) relationship between the number of allowed short-circuit switching processes and the number of diagnostic intervals executed so far. Using the logarithmic relationship, a large number of short-circuit switching processes per diagnostic interval may be allowed, particularly at the beginning of the output stage lifetime. As the output stage circuit approaches the corresponding minimum number of short-circuit switching processes it must withstand at least during its lifetime, the number of short-circuit switching processes per diagnostic interval may be progressively reduced.

[0019] Preferably, the threshold value, particularly for the current diagnostic interval, is predetermined based on the maximum value for the number of short-circuit switching processes that can be executed during the circuit's lifetime, and particularly based on the interval between the number of short-circuit switching processes and the maximum value for the number of short-circuit switching processes that can be executed during the circuit's lifetime. Using this relationship, a large number of short-circuit switching processes per diagnostic interval may be allowed, particularly when the interval for the maximum value is large. As the value approaches the maximum, increasingly fewer short-circuit switching processes per diagnostic interval are allowed to protect the circuit.

[0020] Preferably, the counter reading is incremented only when it is recognized during the evaluation process that the circuit's high-side switch executes a switching-on process during a short circuit to ground and / or the circuit's low-side switch executes a switching-on process during a short circuit to the supply voltage. In the case of an output terminal installed on the ground side, or a low-side switch connected to ground by a terminal, or a switch with a load positioned between the switch and the supply voltage, particularly since a switching-on pulse can have a detrimental effect on the circuit during a short circuit after the supply voltage, in such cases, the switching processes are particularly preferably documented by the counter reading during the occurrence of this type of short circuit. On the other hand, in the case of an output terminal installed on the voltage side, i.e., a high-side switch connected to the supply voltage by a terminal, or a switch with a load positioned between the switch and ground, particularly since a switching-on pulse can have a detrimental effect during a short circuit after ground, in such cases, the switching processes are preferably counted using the counter reading during a short circuit to ground.

[0021] A computing unit according to the present invention, for example, a control unit of a vehicle (automobile), is configured to execute a method according to the present invention, particularly by means of a programming technique.

[0022] Further advantages and embodiments of the present invention are obtained from the detailed description and the accompanying drawings.

[0023] The present invention is schematically illustrated in the drawings by way of embodiments and is described below with reference to the drawings. Brief explanation of the drawing

[0024] FIG. 1 is a schematic diagram illustrating a control device having an output terminal circuit configured to carry out a preferred embodiment of the method according to the present invention. FIG. 2 is a block circuit diagram schematically illustrating a preferred embodiment of the method according to the present invention. FIG. 3 is a diagram schematically illustrating the number of allowed short-circuit switching processes plotted against the number of executed operating cycles that can be determined in the process of a preferred embodiment of the method according to the present invention. Specific details for implementing the invention

[0025] Figure 1 schematically illustrates a control device of a vehicle (automobile) and is marked as 100.

[0026] The control device (100) may be provided as an engine control device for controlling, for example, an internal combustion engine (130), and includes a semiconductor output circuit (120) having the form of a MOSFET bridge circuit having, for example, a high-side switch and / or a low-side switch and a microcontroller (110). By using a corresponding control pulse, the microcontroller (110) can control these semiconductor switching elements of the output circuit (120).

[0027] The output terminal (120) is configured to withstand a minimum number of short-circuit switching processes without damage. If the number of such short-circuit switching processes is exceeded, there may be an increased risk of damage or even destruction of the output terminal (120) and the control device (100).

[0028] To prevent such risks, the control device (100) is configured to implement a preferred embodiment of the method according to the present invention, which is schematically illustrated as a block circuit diagram in FIG. 2 and described below, particularly by programming technology.

[0029] In step (201), the control device (100) or the corresponding vehicle (automobile) is operated normally. In step (202), information regarding the control device (100), in particular, information characterizing the current operation of the control device is detected. In particular, this information relates to the current signal or control pulse of the microcontroller (110) for controlling the output terminal circuit (120), and to the current error present in the control device (100). For example, such information includes the duty cycle of the control signal from the semiconductor switching elements, the current through the semiconductor switching elements, error memory information, or inputs within the error memory.

[0030] In step (203), these information is evaluated as to whether a short-circuit switching process exists, that is, whether a control pulse or a switching (on) pulse is output to the output circuit (120) by the microcontroller (110) while an error state having the form of a short circuit exists within the output circuit (120), in particular whether the high-side switch of the output circuit (120) accordingly performs a switching-on process to ground and / or whether the low-side switch performs a switching-on process to the supply voltage (e.g., battery).

[0031] Unless otherwise, and unless this type of short-circuit switching process exists, information regarding the control device is continuously detected in step (202) and evaluated in step (203).

[0032] On the other hand, if it is recognized in step (203) that such a type of short-circuit switching process exists, in step (204), a counter reading characterizing the number of short-circuit switching processes executed over the lifetime of the output terminal circuit (120) is updated or increased. Accordingly, the current value of this counter reading corresponds to the total number of short-circuit switching processes executed by the output terminal circuit (120) since its lifetime began or since it was first initiated to operate within the control device (100).

[0033] For example, these counter readings can be read at a repair shop and used for error detection, repair, or verification of warranty claims. For example, using the counter readings, it can be checked whether the driver of the vehicle has ignored warning messages, for example, an activated engine check light, over a longer period of time, which may result in a reduction or exclusion of the manufacturer's warranty service for the control unit (100).

[0034] In step (205), the counter reading or the current value of the counter reading is compared with a threshold value and, in particular, with a maximum value for the number of short-circuit switching processes that can be executed during a driving cycle or diagnostic interval for error diagnosis.

[0035] In conventional methods, the number of short-circuit switching processes per allowed diagnostic interval is often statically limited to a constant fixed value. On the other hand, the introduction of an existing counter reading makes it possible to flexibly and dynamically match the number of short-circuit switching processes per allowed diagnostic interval according to the number of short-circuit switching processes already performed by the circuit (120) during its lifetime.

[0036] The threshold value is determined, in particular, based on the number of diagnostic intervals already executed by the output circuit (120) or the vehicle. For example, in the initial stages at the start of the lifespan of the output circuit (120), a greater number of short-circuit switching processes per diagnostic interval may be allowed than in later stages, because the likelihood of the short circuit being healed is higher at the start of the lifespan. In particular, the threshold value for the current diagnostic interval is determined based on a linear or logarithmic relationship between the number of allowed short-circuit switching processes and the number of diagnostic intervals executed.

[0037] Based on the threshold comparison (205), in step (206), the number of short-circuit switching processes that can still be executed in the current diagnostic interval for error diagnosis is limited. Additionally, in step (206), the priority determination of individual short-circuit switching processes can be executed based on the comparison result. Thus, for example, at the beginning of the life of the circuit (120), a higher priority or the highest priority may be assigned to the short-circuit switching processes in the error diagnosis process, and a large number or even an unlimited number of these types of switching processes for error diagnosis per diagnostic interval may be allowed, because in such cases, it is highly likely that the error will be healed or successfully eliminated. In later stages of the life after many diagnostic intervals have been executed, the priority of these types of short-circuit switching processes for error diagnosis may be selected, for example, lower, and only attempts or switching processes for error diagnosis may be predetermined, for example, to prevent possible damage or breakage of the control device (100).

[0038] Figure 3 schematically illustrates a diagram of the number of allowed short-circuit switching processes (m), plotted against the number of executed operation cycles (n).

[0039] The curve (310) represents a corresponding linear relationship, and the curve (320) represents a corresponding algebraic relationship, and according to these, a threshold value for the current diagnostic interval can be predetermined in step (205).

[0040] M indicates the minimum number of short-circuit switching processes that the output terminal circuit (120) must withstand at least during its lifetime.

[0041] 315 indicates, for example, the number of allowed short-circuit switching processes for a diagnostic interval (N1) according to a linear relationship (310), and 325 indicates the number of allowed short-circuit switching processes for a diagnostic interval (N1) according to an algebraic relationship (320).

[0042] According to the algebraic relationship (320), more short-circuit switching processes per diagnostic interval are allowed, particularly at the start of the life of the circuit (120), than according to the linear relationship (310). Additionally, according to the algebraic relationship (320), fewer short-circuit switching processes per diagnostic interval are allowed as the number of times (M) approaches the minimum number.

[0043] For example, based on the algebraic relationship (320), the number of short-circuit switching processes per allowed diagnostic interval can be determined online during the current diagnostic interval using a Taylor expansion.

[0044] When the threshold is predetermined based on the interval between the number of short-circuit switching processes and the maximum number of short-circuit switching processes that can be executed during the circuit's lifetime, a qualitatively similar curve is obtained. Accordingly, a large number of short-circuit switching processes per diagnostic interval may be permitted, particularly when the interval to the maximum value is large. As the value approaches the maximum, fewer short-circuit switching processes per diagnostic interval are permitted to protect the circuit.

Claims

Claim 1 A method for monitoring short-circuit switching processes of an output terminal circuit (120) of a control device (100), wherein information regarding the control device (100) is detected (202), and whether a short-circuit switching process exists and whether the output terminal circuit (120) performs a switching-on process during a short circuit is evaluated (203), and if it is recognized during the evaluation that a short-circuit switching process exists, a counter reading characterizing the number of short-circuit switching processes performed over the lifespan of the output terminal circuit (120) is updated (204), and the counter reading is updated (204) if it is recognized during the evaluation that the high-side switch of the output terminal circuit (120) performs a switching-on process during a short circuit to ground and / or the low-side switch of the output terminal circuit (120) performs a switching-on process during a short circuit to the battery. Claim 2 In claim 1, a method for monitoring short-circuit switching processes of the output terminal circuit of the control device (100) including short-circuit switching processes executed during the diagnostic interval of the control device (100) including short-circuit switching processes executed during the error diagnosis process of the control device (100) according to the counter reading, and a method for determining or limiting the priority of short-circuit switching processes executed during the diagnostic interval of the control device (100). Claim 3 A method for monitoring short-circuit switching processes of an output circuit of a control device, wherein, in claim 1 or 2, a counter reading is compared with a predetermined threshold value (205), and the predetermined threshold value is a predetermined maximum value for the number of short-circuit switching processes that can be executed during a diagnostic interval. Claim 4 A method for monitoring short-circuit switching processes of the output circuit of a control device, wherein, in paragraph 3, the threshold value is predetermined according to the number of diagnostic intervals. Claim 5 A method for monitoring short-circuit switching processes of the output terminal circuit of a control device, wherein the threshold value is predetermined according to the relationship (310) between the number of short-circuit switching processes (m) and the number of diagnostic intervals (n) in paragraph 4. Claim 6 A method for monitoring short-circuit switching processes of an output circuit of a control device, wherein the threshold value is predetermined according to a maximum value for the number of short-circuit switching processes that can be executed during the lifetime of the output circuit (120). Claim 7 A method for monitoring short-circuit switching processes of an output circuit of a control device, wherein the threshold value is predetermined according to the interval between the number of short-circuit switching processes (m) and the maximum value for the number of short-circuit switching processes that can be executed during the lifetime of the output circuit (120). Claim 8 A method for monitoring short-circuit switching processes of an output circuit of a control device, wherein, in paragraph 3, a priority determination of the short-circuit switching process is performed (206) according to a comparison (205) and / or the number of short-circuit switching processes is limited (206). Claim 9 delete Claim 10 A computing unit (100) configured to execute all method steps of the method according to paragraph 1 or 2.

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