ELECTRONIC CONTROL UNIT

Abstract

Electronic control unit, which includes: a load driver circuit (102) that controls a load a control circuit (104) that controls the load driver circuit (102); and a diagnostic circuit (103) that diagnoses an output state of the load driver circuit (102) and outputs a diagnostic result to the control circuit (104), wherein the diagnostic circuit (103) outputs a diagnostic completion flag to the control circuit (104) indicating whether a diagnostic option is available.

Description

Technical field

[0001] The present invention relates to the control of an electronic control unit and relates in particular to a technique which is effective by being applied to an in-vehicle electronic control unit which has a fault diagnosis function. Technical background

[0002] An electronic control unit of a vehicle contains various sensors that detect necessary information, such as the states and control environments of a power machine; an electronic control unit (ECU) that immediately performs an arithmetic operation on the types of information received from these sensors and outputs optimal control information; and an actuator (a drive device) that is driven according to the optimal control information, with the optimal control of each electronic control system being carried out in cooperation with each other.

[0003] The actuators, such as an engine ignition electrode (ignition device), an injector nozzle (fuel injection device), and an anti-lock braking system (ABS), are electrical loads, while the ECUs are load driver devices that control these electrical loads.

[0004] As mentioned above, the ECU (Electrocontrol Unit) performs optimal control based on the signals from the sensors. However, an on-board diagnostics (OBD) function is provided to diagnose defects, such as a sensor disconnection or malfunction, so that the vehicle can demonstrate safety and environmental performance.

[0005] Anomaly diagnostics in the load driver device may be necessary to detect a supply fault, short circuit, or disconnection. Generally, monitoring the voltage and current of a driver output (driver circuit) and comparing the monitored value to a threshold determines whether the driver output is normal or anomalous. A diagnostic result is sent to a control circuit, such as a microcomputer, which controls the driver. If the result is anomalous, a control action is then performed based on the diagnostic result, such as halting the driver's operation.

[0006] Due to safety requirements and the tightening of emissions regulations, it is necessary to perform anomaly diagnostics and driver control, especially for the vehicle, in accordance with safety, speed and a wide range of driving conditions, based on the results, and to prepare countermeasures in each case.

[0007] As a specific example, in the event of a fault, such as a supply fault anomaly in a deep-side driver, a large current continues to flow in a driver circuit, which can consequently cause a serious fault, such as the melting of a wiring pattern. As a prior art technique for abruptly stopping the driver to avoid such a fault, there is a method of immediately disabling the driver before the control circuit is notified when the fault is detected.

[0008] PTL 1 describes, for example, that "a diagnostic start signal is input from a microcontroller via serial communication. When the diagnostic start signal is received, a driver IC reads the ON or OFF state of each driver circuit from a ROM into a register group. Each driver diagnostic circuit performs the diagnostics in the ON or OFF state according to a register value. If the fault is detected during this phase, information is written to a diagnostic register group that stores a fault operating mode and a driver circuit number. The driver circuit in which the fault is detected is disabled, and this information is reported to the microcontroller via high-speed serial communication based on this data."PTL 2 discloses a load driver with a circuit arrangement for detecting a wire break, wherein a current sensing device is provided that is connected between a point in the ground line of a control circuit and a point in the load current path. That is, if a current flows from the former to the latter point, this is interpreted as a wire break and detected. Furthermore, PTL 3 describes a load control circuit with an integrated diagnostic circuit for detecting load anomalies. That is, in order to detect faults in the diagnostic circuit itself, a pseudo-fault signal is fed into the diagnostic circuit when it is not currently checking for load anomalies. List of oppositions patent literature PTL 1: JP 2014 - 46 730 A PTL 2: DE 10 2008 037 400 A1 PTL 3: US 2016 / 341 776 A1 Summary of the invention: Technical problem

[0009] If, in the diagnostic procedure of the prior art described above, a voltage is monitored as a means of diagnosing an anomaly, the diagnosis can only be performed when the driver circuit is in the OFF state, because a difference between a normal state and an anomalous state cannot be confirmed if the output driving the load in a state where the driver (the driver circuit) is in the ON state is connected to GND or a power supply via a switch.

[0010] Meanwhile, the diagnostic procedure can be performed not only in the ON state, where current flows through the driver (the driver circuit), even if current is detected. Consequently, in the prior art, if there is no diagnosable way to determine the ON or OFF state of the driver, the diagnostic result is sent to the control circuit as normal, even though the result is not confirmed.

[0011] The control circuit determines the state of the driver's output based on several diagnostic results indicating normal or abnormal behavior from the driver. However, because a faulty "normal" diagnostic result can be sent for the reasons mentioned above, there is a problem: it takes time to make a reliable determination.

[0012] Therefore, it is an object of the present invention to create an electronic control unit that can perform a highly accurate fault diagnosis in a short time, as an electronic control unit with a fault diagnosis function. Solution to the problem

[0013] The problem is solved by the features of the independent patent claim. Advantageous embodiments of the invention are described in the dependent claims. Advantageous effects of the invention

[0014] According to the present invention, it is possible to realize an electronic control unit that can perform a highly accurate fault diagnosis in a short time as an electronic control unit with a fault diagnosis function.

[0015] Further tasks, configurations and effects will be made obvious in the following descriptions of the embodiments. Brief description of the drawings Fig. Figure 1 is a circuit configuration diagram illustrating a configuration of a load driver device according to a first embodiment of the present invention. Fig. 2 is a timing diagram that shows an example of the operation of a load driver circuit 102 according to Fig. 1 illustrates. Fig. 3 is a flowchart that describes an anomaly detection procedure using a control circuit 104 according to Fig. 1 illustrates. Fig. 4 is a timing diagram that shows an example of the operation of the load driver circuit 102 according to Fig. 1 illustrates. Fig. 5 is a timing diagram that shows an example of the operation of the load driver circuit 102 according to Fig. 1 illustrates. Fig. Figure 6 is a timing diagram illustrating an example of the operation of a load driver circuit according to a second embodiment of the present invention. Fig. Figure 7 is a circuit configuration diagram illustrating a configuration of a load driver device according to a third embodiment of the present invention. Fig. Figure 8 is a circuit configuration diagram illustrating a configuration of a load driver device according to a fourth embodiment of the present invention. Fig. Figure 9 is a circuit configuration diagram illustrating a configuration of a load driver device according to a fifth embodiment of the present invention. Description of the embodiments

[0016] The following describes embodiments of the present invention with respect to the drawings. In the drawings, the same configurations are designated by the same reference numerals, and the detailed description of redundant sections is omitted. First embodiment

[0017] A load driver device (electronic control unit) according to a first embodiment of the present invention is described with respect to the Fig. 1 to 5 described.

[0018] Fig. Figure 1 illustrates a circuit configuration of the load driver device (electronic control unit) of the present embodiment. A load driver device 101 of the present embodiment comprises a load driver circuit 102 and a control circuit 104 that controls the load driver circuit 102. The load driver circuit 102 includes a diagnostic circuit 103 that diagnoses an output state of the load driver device 101 (load driver circuit 102) and outputs a diagnostic result to the control circuit 104.

[0019] The load driver circuit 102 drives a load based on a control signal output by the control circuit 104. Fig. Figure 1 illustrates an example of an inductive load containing a winding wire (a coil) 105 and a capacitive element (a capacitor) 106. The diagnostic circuit 103 diagnoses the output state of the load driver device 101 by monitoring an output voltage or output current of the load driver circuit 102 and sends (out) the diagnostic result and a diagnostic completion marker to (out) the control circuit 104 when a read command is received from the control circuit 104.

[0020] The “diagnostic completion marker” is a marker that indicates whether there is a possibility to diagnose the output state of the load driver device 101 (load driver circuit 102) by the diagnostic circuit 103.

[0021] The diagnostic circuit 103 diagnoses the output state of the load driver device 101 only when the load driver circuit 102 is in an ON or OFF state. For example, if the load driver circuit 102 has a deep-side driver configuration, the diagnostic circuit 103 diagnoses that the output state is a normal state if the output voltage is close to a battery voltage during a period when the load driver circuit 102 is in the OFF state, or an anomalous disconnect or short-circuit state if the output voltage is close to a GND potential, in order to diagnose a disconnect or short-circuit anomaly.

[0022] When a supply fault is diagnosed, it is possible to diagnose the supply fault when an excessive current flows during a period in which the load driver circuit 102 is ON, and a normal state when the current is within a normal range.

[0023] Even if the load driver circuit 102 has another circuit configuration, such as a high-side driver, the same applies to the following operations, as long as a diagnosable period is restricted to the ON or OFF state.

[0024] The diagnostic circuit 103 generates the diagnostic completion marker based on a period during which the diagnostic procedure is performed.

[0025] Fig. Figure 2 illustrates a timing diagram when, in the present embodiment, the diagnostic circuit 103 performs the diagnosis only in one period in which the load driver circuit 102 is in the OFF state, and a state of an output terminal is “anomalous”.

[0026] A diagnostic result before collection in Fig. 2 represents a result of the diagnosis performed by the diagnostic circuit 103 during a diagnosable period when the driver control is low, i.e., during a period when the load driver circuit 102 is in the OFF state but fixed to "normal," which is a default value during a non-diagnosable period when the driver control is high. A post-capture diagnostic result, which represents a register storing the information output to the control circuit 104, stores a value and captures it (retains a state) if the pre-capture diagnostic result becomes anomalous, as shown in (e) after. Fig. 2 is illustrated. As shown in (a), (c), (d) and (g) according to Fig. As illustrated in Figure 2, when a read command is received from the control circuit 104, the value of the diagnostic result is stored and captured again before being collected (the state is retained) after the read command has been sent to the control circuit 104.

[0027] By operating in this manner, the result diagnosed by the diagnostic circuit 103 in the diagnosable period is retained until the result is first read by the control circuit 104 after the period has changed to the non-diagnosable period, as in (c) after Fig. 2 is illustrated.

[0028] As in (c) after Fig. As illustrated in Figure 2, after deleting the diagnostic result after capture by the read command in the non-diagnosable period, the "normal" value, which is the default diagnostic result value, is stored in the diagnostic result after capture. As in (d) after Fig. As illustrated in Figure 2, if the diagnostic circuit 103 receives the read command again while the non-diagnostic period continues, a value indicating “normal” (hereinafter referred to as the non-diagnostic “normal”) will be output to the control circuit 104 as the diagnostic result, even if the driver output state is actually “anomalous”.

[0029] A diagnosable period signal, which is an internal signal of the diagnostic circuit 103, is high while the driver control is low (OFF), which is the diagnosable period, and is low while the driver control is high (ON), which is the non-diagnosable period.

[0030] As in (e) after Fig. As illustrated in 2, the diagnostic completion marker becomes high and is captured (the condition is retained) when the diagnosable period signal becomes high. As shown in (a), (c), (d) and (g) Fig. As illustrated in Figure 2, when the diagnostic circuit 103 receives the read command from the control circuit 104 after the value of the diagnostic termination marker has been sent to the control circuit 104, the value of the diagnosable period signal is captured again (the state is retained).

[0031] Such an operation results in a high diagnostic completion marker being read if it is the diagnosable period between a previous read command and a current read command, and a low diagnostic completion marker being read if it is not a diagnosable period.

[0032] Control circuit 104 determines a read result based on the diagnostic result read and the value of the diagnostic completion marker. If the diagnostic completion marker is high, indicating the diagnostic period between the previous and current reads, and if the diagnostic result read is a plausible result after the diagnosis has been performed, control circuit 104 processes the diagnostic result read as the read result as is.

[0033] If, meanwhile, the diagnostic completion marker is low because the diagnosis is not executed after the previous read, even if the read value of the diagnostic result is "normal," control circuit 104 processes the read result as "indeterminate." In other words, control circuit 104 determines the diagnostic result to be "indeterminate" if the diagnostic result received from diagnostic circuit 103 is "normal" and the diagnostic completion marker is low (no diagnostic possibility). That is, if the diagnostic result is determined to be "indeterminate," control circuit 104 ignores the diagnostic result from diagnostic circuit 103.

[0034] Fig. Figure 2 illustrates that the diagnostic circuit 103 performs the diagnosis during a period when the load driver circuit 102 is in the OFF state. However, even if the diagnosis is performed during a period when the load driver circuit 102 is ON, it is determined that it is diagnosable during a period when the driver control is high, while it is determined to be non-diagnosable during a period when the driver control is low. Another signal operates according to a diagnosable or non-diagnosable state, thus achieving the same effect.

[0035] It has been described that the diagnosis completion marker is set to high during a period in which the diagnosis is executed and to low during a period in which the diagnosis is not executed. However, the diagnosis completion marker can also be set to "low" during a period in which the diagnosis is executed and to "high" during a period in which the diagnosis is not executed.

[0036] The control circuit 104 ultimately determines whether the output is "normal" or "anomalous" based on the diagnostic result read by the diagnostic circuit 103. The control circuit 104 counts the "anomalous" reading, taking into account the possibility that the diagnostic circuit 103 might incorrectly diagnose an "anomalous" result due to noise, a voltage surge, or the like, and determines that the output is "anomalous" if the anomalous condition persists a certain number of times.

[0037] For example, the diagnostic circuit 103 captures (retains) the diagnostic result detected during a period in which the diagnosis of the ON or OFF state of the load driver circuit 102 (driver control) is performed, clears the captured diagnostic result when the control circuit 104 is read, captures the diagnostic termination marker as high during a period in which the diagnosis of the output state of the load driver circuit 102 (driver control) is performed, clears the captured diagnostic termination marker so that it is low when the control circuit 104 is read, and outputs a diagnostic termination marker to the control circuit 104 indicating whether there is a diagnostic opportunity between the previous and current read of the diagnostic result, as shown in (b) to (e) after Fig. 2 is illustrated.

[0038] Fig. Figure 3 illustrates the anomaly detection process (an anomaly detection procedure) of the final output terminal state by the control circuit 104. The control circuit 104 receives an anomaly detection start signal and begins the anomaly detection process (step 301).

[0039] First, the diagnostic result of diagnostic circuit 103 is read (step S302), and it is determined whether the read result is "anomalous" (step S303). If the read result is "anomalous", 1 is added to the count value (step S304).

[0040] The process then determines whether the count reaches a specific number of times (N times) (step S305). If the count does not reach this number, the processing returns to reading the diagnostic result (step S302), while if the count does reach this number, the anomaly detection is confirmed (step S306), at which point the anomaly detection process is terminated (step S310).

[0041] Meanwhile, if the result read in step S303 is not "anomalous," it is determined whether the result is "indeterminate" or "normal" (step S307). If the result is "indeterminate," the processing returns to reading the diagnostic result, while the previous value is retained as the count (step S308). If the result is "normal," the count is cleared to 0, and the processing returns to reading the diagnostic result (step S309).

[0042] Because there is no diagnostic completion marker in the current state of the art, there is no sequence of events if this occurs in Fig. As illustrated in Figure 3, the read result is "undefined," and the counter is always cleared if the read result is not "anomalous." That is, if the output becomes "anomalous" and the undiagnosed "normal" result is read while "anomalous" results are continuously read, the continuous reading of "anomalous" results is interrupted, and the counter must be restarted from zero.

[0043] As with the present invention, if the diagnostic result is "normal," it is possible to distinguish, using the diagnostic completion marker, whether the result is "normal" or "indeterminate." Consequently, when using the control circuit 104, if the result is anomalous, by determining that the result is "indeterminate" and retaining the counter reading for anomalous values, it is not necessary to restart the count, even if the undiagnosed "normal" value is read while the "anomalous" value is read continuously. This reduces the time required for anomaly determination using the control circuit 104.

[0044] Under conditions where a load drive cycle is long and the duty cycle is small (large if the diagnosis is performed during a period when the driver control is ON), the diagnostic capabilities are limited compared to the intervals at which the read commands are issued. In the prior art, if it is difficult to continuously read the anomalous diagnostic result, or if there is no diagnosable period between read commands because all read results can be ignored as "indeterminate" (not used as final determining material for the control circuit 104), the reading of "anomalous" results can be counted continuously. Because the anomaly can be determined by the control circuit 104, the effect is consequently particularly large.

[0045] Fig. Figure 4 illustrates a timing diagram when, in the present embodiment, the diagnostic circuit 103 performs the diagnosis only in one period in which the load driver circuit 102 is in the OFF state and the output terminal is in "normal" condition. The operating principle of each signal is the same as that described in Fig. Figure 2 illustrates this, but the diagnostic result before collection, the diagnostic result after collection, and the diagnostic value in Fig. 4 are constantly normal.

[0046] Of these signals, the “normal” signal, which is the result of the diagnosis performed by the diagnostic circuit 103, is read when there is a diagnosable period between the previous and the current read command(s), as shown in (a), (c) and (g) after Fig. 4 is illustrated, but if there is no diagnosable period, as in (d) after Fig. As illustrated in 4, the undiagnosed "normal" result is displayed. However, because a value in (d) after Fig. If the value read from the diagnostic completion marker is low, the control circuit 104 can determine that the undiagnosed "normal" is not the result of the diagnosis performed by the diagnostic circuit 103, whereby the read result can be processed as "unspecified".

[0047] Even if the output terminal is in the "normal" state, the same effect can be achieved if the diagnostic circuit 103 performs the diagnosis in a period in which the load driver circuit 102 is as described below. Fig. 2 ONE is.

[0048] If the control circuit 104 determines "normal" based on the result read by the diagnostic circuit 103, and considering the possibility that, as in the case of anomaly detection, the normal state is not diagnosed even though "normal" is read, "normal" is determined if "normal" is continuously read a certain number of times, because the diagnostic completion marker is not used in the prior art and the undiagnosed "normal" and the "normal" that is the diagnostic result of the diagnostic circuit cannot be distinguished.

[0049] Because the present embodiment allows for a reliable distinction between "normal" and "indeterminate" results, the continuous reading described above becomes unnecessary, as it is possible to determine a "normal" result from a single reading. Consequently, it is possible to shorten the determination time.

[0050] As in the case of anomaly detection, when the possibility of outputting the undiagnosed "normal" value increases under conditions where a load drive cycle is long and a duty cycle is small (large if the diagnosis is performed during a period when the driver control is ON), it takes more time because a probabilistically sufficient number of readings of "normal" are required for the determination using the prior art control circuit 104. Consequently, according to the present embodiment, the effect of determining "normal" becomes greater when the diagnostic possibilities are smaller.

[0051] In the Fig. 2 and Fig. 4. The diagnosable period and the non-diagnosable period are switched at the same time as a rising edge and a falling edge of the driver control. However, in an actual product (load driver device), the diagnosable period may not coincide with the period in which the driver control is high or low, as in a case where a filter time is being prepared for noise removal or a time is being prepared to control a voltage at the time of disconnection by a small current in order to distinguish between the disconnection and a short circuit or supply fault.

[0052] Fig. Figure 5 illustrates a timing diagram when, in the present embodiment, the diagnostic circuit 103 performs the diagnosis only during a period in which the load driver circuit 102 is in the OFF state, it takes a certain amount of time to complete the diagnosis, and the output terminal state is "anomalous." Even if the driver control is deep, there is a possibility that the diagnosis will not be completed during a maximum time T required by the diagnostic circuit 103 for the diagnosis from the fall-off edge of the driver control at which the diagnostic circuit 103 begins the diagnosis.

[0053] How between (a) to (c) and (d) to (f) in Fig. As illustrated in Figure 5, this period is consequently the non-diagnostic period, during which the diagnosable period signal becomes low. When the time T elapses from the falloff edge of the driver control because the diagnosis of the diagnostic circuit 103 is reliably completed, it is determined to be diagnosable, during which the diagnosable period signal becomes high, as shown in (c) and (h) after Figure 5. Fig. 5 is illustrated.

[0054] As in (f) to (j) in Fig. As illustrated in Figure 5, the diagnostic circuit 103, for example, increases the diagnostic termination marker to high after a predetermined period (T) has elapsed since the load driver circuit 102 (driver controller) switched to the OFF state, while it decreases the diagnostic termination marker to low when a control state of the load driver circuit 102 (driver controller) is changed and the diagnosis of the output state of the load driver circuit 102 (driver controller) is completed.

[0055] The diagnostic circuit 103 increases the diagnostic termination marker to high after the specified period (T) has elapsed since the load driver circuit 102 (driver controller) switched to the OFF state, while it decreases the diagnostic termination marker to low when a transfer request (a read command) of the diagnostic result is received from the control circuit 104 after the control state of the load driver circuit 102 (driver controller) has changed and the diagnosis of the output state of the load driver circuit 102 (driver controller) is complete.

[0056] If, meanwhile, the diagnostic circuit 103 performs the diagnosis during a period in which the load driver circuit 102 (driver controller) is ON, the diagnostic circuit 103 increases the diagnostic completion marker to high after the predetermined time (T) has elapsed since the load driver circuit 102 (driver controller) of the diagnostic circuit 103 switched to the ON state, while it decreases the diagnostic completion marker to low when the control state of the load driver circuit 102 (driver controller) changes and the diagnosis of the output state of the load driver circuit 102 (driver controller) is completed, as described above.

[0057] The diagnostic circuit 103 increases the diagnostic completion marker to high after the predetermined period (T) has elapsed since the load driver circuit 102 (driver controller) switched to the ON state, while it decreases the diagnostic completion marker to low when the transfer request (the read command) of the diagnostic result is received from the control circuit 104 after the control state of the load driver circuit 102 (driver controller) has changed and the diagnosis of the output state of the load driver circuit 102 (driver controller) is complete.

[0058] Accordingly, as in (g) after Fig. Figure 5 illustrates that the diagnostic completion marker is deep during a period in which there is a possibility that the diagnosis will not be completed, with the control circuit 104 processing the read result as "indeterminate", even if the driver control is deep and the read value of the diagnostic result is "normal".

[0059] The diagnosis using the diagnostic circuit 103 can even be completed before the time T has elapsed since the fall edge of the driver control.

[0060] At this point, as in (b) after Fig. Figure 5 illustrates one possibility: the diagnostic result read during the non-diagnostic period, when the driver control is low, becomes "anomalous." However, at this point, control circuit 104 processes the read result as "anomalous," even if the diagnostic termination marker is low. As explained above, the diagnosable period signal can operate according to the timing control during the diagnostic period if the diagnosable period is not synchronized with the driver control.

[0061] To distinguish the undiagnosed "normal" from the "normal" that reflects the result of the diagnosis performed by the diagnostic circuit 103, the control circuit 104 can, in addition to the method of using the diagnostic completion marker as in the present embodiment, perform processing to determine whether the diagnosable period exists. This is achieved by storing and comparing a period in which the load driver circuit 102 is switched ON and a period in which the load driver circuit is switched OFF, according to the control signals at the time the read command is transmitted, after the transmission of the previous read command. However, this method suppresses the processing capability of the control circuit 104.

[0062] As described above, according to the load driver device (electronic control unit) of the present embodiment, it is possible to shorten the time required to determine the output state of the load driver device 101 without suppressing the processing capacity of the control circuit 104.

[0063] Accordingly, it is possible to implement an electronic control device in the load driver device (electronic control unit) with a fault diagnosis function, which can perform a highly accurate fault diagnosis in a short time.

[0064] The control circuit 104 can continue normal control of the load driver circuit 102 if the final determination result of the output state of the load driver circuit 102 is “normal” based on the diagnostic result and the diagnostic completion marker, and can execute the control in such a way that the load driver circuit 102 is stopped if the final determination result is “anomalous”.

[0065] By implementing such control, stable control operation can be carried out without stopping the load driver device (electronic control unit) more than necessary, thereby improving the reliability of the load driver device (electronic control unit).

[0066] Notification means, such as a warning light, for reporting an “anomaly” of the load driver device (electronic control unit) 101 may be provided inside or outside the load driver device (electronic control unit) 101, wherein the control circuit 104 can turn on the warning light (notify the outside) if the final determination result of the output state of the load driver circuit 102 based on the diagnostic result and the diagnostic completion marker is “anomalous”.

[0067] This leads to early detection of an “anomaly” of the load driver device (electronic control unit) 101, allowing for appropriate maintenance (repair / replacement) of the load driver device (electronic control unit) 101. Second embodiment

[0068] A load driver device (electronic control unit) according to a second embodiment of the present invention is described with respect to Fig. 6 described. Because a circuit configuration diagram in the present embodiment with Fig. Since 1 is common in the first embodiment, the redundant description is omitted.

[0069] Fig. Figure 6 is a timing diagram illustrating the operation of the load driver circuit 102 in the present embodiment.

[0070] While in the first embodiment there is the Diagnosable Period signal and the operation in which the diagnostic termination marker is high in the diagnosable period and low in the non-diagnosable period, in the present embodiment there is no Diagnosable Period signal and the diagnostic termination marker has the same operation as the Diagnosable Period signal in the first embodiment.

[0071] This means that the diagnostic termination marker is not captured (the state is not maintained) even after it has become high, falling immediately upon entering the non-diagnostic period. In this case, the diagnostic termination marker indicates whether a time at which the control circuit 104 reads the diagnostic result is the diagnosable period. In the present embodiment, the control circuit 104 determines that the diagnostic result confirmed in the diagnosable period is "normal" or "indeterminate," as shown in (c) and (g) after [reference]. Fig. 6 is illustrated, but it can reliably determine that the undiagnosed ‘normal’ is ‘indeterminate’, as in (d) according to Fig. Figure 6 illustrates this.

[0072] Fig. Figure 6 illustrates a case in which the output state of the load driver device 101 is "normal". However, in the case of "anomalous", if the read value of the diagnostic result is "anomalous" and the read value of the diagnostic termination marker is low, the control circuit 104 determines that the read result is "anomalous" because the diagnostic result only becomes "anomalous" if the diagnostic circuit 103 detects an "anomalous" output.

[0073] Because the read value of the diagnostic result only becomes "normal" if the non-diagnostic period from the reading continues, the diagnostic completion marker becomes deep, making it possible to determine that the read result is "indeterminate". Consequently, if the initial state of the load driver device 101 is "anomalous", the present embodiment can achieve the same effect as the first embodiment.

[0074] In Fig. 6. The diagnosable period coincides with a period in which the driver control is low. However, the same effect is achieved by setting the diagnostic completion marker to high according to the diagnosable period, even if the diagnosis is performed in a period in which the driver control is high and the diagnosable period and the non-diagnosable period differ in time from the driver control. Third embodiment

[0075] A load driver device (electronic control unit) according to a third embodiment of the present invention is described with respect to Fig. 7 described. Fig. Figure 7 is a circuit configuration diagram of the load driver device (electronic control unit) in the present embodiment.

[0076] In the present embodiment, the configurations of a driver IC 702 and a microcontroller 703 differ from those in the first embodiment. Because the other configurations are the same as those in the first embodiment, the redundant description is omitted.

[0077] In a load driver device (electronic control unit) 701 of the present embodiment, with respect to the configuration of the first embodiment, the control circuit 104 is replaced by the microcontroller 703 and the load driver circuit 102 is replaced by the driver IC 702. The communication between the microcontroller 703 and the driver IC 702 is serial communication.

[0078] In the present embodiment, all control signals, the read command, the diagnostic result, and the diagnostic completion marker are sent and received via serial communication, as described in Fig. Figure 7 illustrates this. For example, the diagnostic circuit 103 sends the diagnostic result and the diagnostic completion marker via serial communication to the microcontroller 703 (the control circuit).

[0079] According to the present embodiment, the number of connections of the driver IC 702 and the microcontroller 703 can be reduced. This reduces the probability of failure, such as a disconnection, and improves the reliability of the load driver device (electronic control unit) 701.

[0080] Furthermore, by including the diagnostic result and the diagnostic completion marker in the same frame and sending the diagnostic result to the 703 microcontroller (the control circuit), the 703 microcontroller (the control circuit) can assess the read result more quickly. Fourth embodiment

[0081] A load driver device (electronic control unit) according to a fourth embodiment of the present invention is described with respect to Fig. 8 described. Fig. Figure 8 is a circuit configuration diagram of the load driver device (electronic control unit) in the present embodiment.

[0082] In the present embodiment, the configurations of a low-side driver 808, a high-side driver 809, an ignition electrode 803, an ignition coil 804, and a spark plug 805 differ from those of the first embodiment. Because the other configurations are the same as those in the first embodiment, the redundant description is omitted.

[0083] In the present embodiment, a load driver device (electronic control unit) 801 acts as a pre-driver of the ignition electrode 803, wherein, when the driver control is high, a VCC voltage is output, while an output current is controlled by setting the high-side driver 809 to ON and the low-side driver 808 to OFF. That is, a load driver circuit 802 controls the ignition electrode 803.

[0084] When the driver control is low, an output is set to GND by setting the low-side driver 808 to ON and the high-side driver 809 to OFF. The energy of the ignition coil 804 is stored by setting the ignition electrode 803 to ON when the output of the load driver device becomes VCC. When the output of the load driver device 801 becomes GND, the energy of the ignition coil 804 is released by setting the ignition electrode to OFF, causing the spark plug 805 to produce a spark. A resistive element 806 and a capacitive element (capacitor) 807 are connected by wiring that links the load driver device 801 and the ignition electrode 803.

[0085] The diagnostic circuit 103 monitors a current output by the high-side driver 809 and detects that the output of the load driver device 801 is disconnected when the current is equal to or less than a certain level.

[0086] The activation cycle of the ignition electrode 803 depends on the engine speed; as the engine speed decreases, the cycle becomes longer. Because the period during which the ignition electrode 803 is ON at that time is shorter than the activation cycle, the period during which the diagnostic circuit 103 can be diagnosed is also shortened. For example, if the engine speed is 800 rpm -1 If the control cycle is approximately 120 ms, and the cycle in which the read command is issued by the control circuit 104 is 10 ms, the diagnostic circuit 103 performs the diagnosis once every 12 times the cycle in which the read command is issued.

[0087] As described in the first embodiment, the undiagnosed "normal" state can be determined as "undetermined" using the diagnostic termination marker, with the final determination of "anomalous" or "normal" of the initial state being made using the control circuit 104. However, this effect is particularly significant when the diagnosable possibilities are limited, such as in a case where the drive cycle is long and the duty cycle is low, making the determination difficult to perform in the prior art.

[0088] If the ignition electrode 803 is driven as a load, as in the present embodiment, the diagnosis can be completed more quickly, especially when the engine speed is low. The same applies to other cases where a load is used, on which a control cycle of an injector (fuel injection device) and a duty cycle depend on environmental factors such as engine speed and temperature. Using the diagnostic completion marker, it is possible to perform the diagnosis without being influenced by the vehicle's driving condition or the environment.

[0089] It is also possible to control the ignition electrode by connecting the load driver circuit 802 to the injector (fuel injection device) of the engine, although this is in Fig. 8 is not illustrated. Fifth embodiment

[0090] A load driver device (electronic control unit) according to a fifth embodiment of the present invention is described with respect to Fig. 9 described. Fig. Figure 9 is a circuit configuration diagram of the load driver device (electronic control unit) in the present embodiment.

[0091] In the present embodiment, the configurations of a driver 905 of the deep side and a relay 903 differ from those in the first embodiment.

[0092] Because the other configurations are the same as those in the first embodiment, the redundant description is omitted.

[0093] In the present embodiment, a load driver circuit 902 controls a relay 903. When the driver 905 is ON, the relay 903 is also ON, supplying battery power to circuits, such as an actuator and a controller, connected to one end of the relay 903. In such a configuration, there is an extremely small possibility of changing the control state, such as a case where, from when the vehicle starts until when the vehicle stops, setting the driver 905 and the relay 903 to ON continues to supply power to other circuits. Consequently, there is almost no possibility of performing diagnostics only while the driver control is in the OFF state.

[0094] As explained above, it is possible to forcibly generate a diagnostic capability by switching between the ON and OFF states of the load driver circuit 902 during a period shorter than that in a case where a load is operating mechanically, if the control state of the load driver circuit 902 hardly changes or if the control cycle is extremely long and the read result remains in the "indeterminate" state for a certain period.

[0095] In the case of the present embodiment, for example, the diagnosis can be carried out by switching off the relay for a period of about several hundred µs or less if a mechanical relay is used for relay 903, because a response time is generally several ms.

[0096] This means that the control circuit 104 controls the load driver circuit 902 in such a way that the diagnostic circuit 103 can diagnose the output state of the load driver circuit 902 when the diagnostic termination marker indicates that there is no diagnostic period during a specified period or longer.

[0097] The present invention is not limited to the embodiments mentioned above and includes various examples of modification.

[0098] The embodiments mentioned above have been described in detail, for example, to facilitate a clear understanding of the present invention. These descriptions are not limited to necessarily including all components described. Some components of a particular embodiment can be substituted into the components of another embodiment, while the components of another embodiment can be added to the components of a particular embodiment. Additionally, the components of another embodiment can be added to, removed from, and substituted into some of the components of the embodiments mentioned above. List of reference symbols 101, 701, 801, 901 Load driver device (electronic control unit) 102, 802, 902 load driver circuit 103 Diagnostic circuit 104 Control circuit 105 winding wire (coil) 106, 807, 904 Capacitance element (capacitor) 702 Driver IC 703 Microcontroller 808, 905 drivers of the deep side 809 High-side drivers 803 Ignition electrode 804 Ignition coil 805 Spark plug 806 Resistor element 903 relays

Claims

[1] Electronic control unit comprising: a load driver circuit (102) that controls a load a control circuit (104) that controls the load driver circuit (102); and a diagnostic circuit (103) that diagnoses an output state of the load driver circuit (102) and outputs a diagnostic result to the control circuit (104), wherein the diagnostic circuit (103) outputs a diagnostic completion flag to the control circuit (104) indicating whether a diagnostic option is available. [2] Electronic control unit according to claim 1, wherein the control circuit (104) determines that the diagnostic result is indeterminate when the diagnostic result from the diagnostic circuit (103) is normal and the diagnostic completion marker indicates that there is no diagnostic possibility. [3] Electronic control unit according to claim 2, wherein the control circuit (104) ignores the diagnostic result from the diagnostic circuit (103) if it is determined that the diagnostic result is indeterminate. [4] Electronic control unit according to one of claims 1 to 3, wherein the control circuit (104) increases the diagnostic termination marker to high after a predetermined period has elapsed since the load driver circuit (102) switched to an OFF state, and decreases the diagnostic termination marker to low when a control state of the load driver circuit (102) is changed and the diagnosis of the output state of the load driver circuit (102) is terminated. [5] Electronic control unit according to one of claims 1 to 3, wherein the control circuit (104) increases the diagnostic termination marker to high after a predetermined period has elapsed since the load driver circuit (102) switched to an ON state, and decreases the diagnostic termination marker to low when a control state of the load driver circuit (102) is changed and the diagnosis of the output state of the load driver circuit (102) is terminated. [6] Electronic control unit according to any one of claims 1 to 3, wherein the control circuit (104) increases the diagnostic completion marker to high after a predetermined period has elapsed since the load driver circuit (102) switched to an OFF state, and decreases the diagnostic completion marker to low when a transmission request of the diagnostic result is received by the control circuit (104) after a control state of the load driver circuit (102) has been changed and the diagnosis of the output state of the load driver circuit (102) has been completed. [7] Electronic control unit according to any one of claims 1 to 3, wherein the control circuit (104) increases the diagnostic completion marker to high after a predetermined period has elapsed since the load driver circuit (102) switched to an ON state, and decreases the diagnostic completion marker to low when a transmission request of the diagnostic result is received from the control circuit (104) after a control state of the load driver circuit (102) has been changed and the diagnosis of the output state of the load driver circuit (102) is completed. [8] Electronic control unit according to any one of claims 1 to 3, wherein the control circuit (104) captures a diagnostic result detected during a period in which the diagnosis of the ON or OFF state of the load driver circuit (102) is performed, and deletes the captured diagnostic result when the control circuit (104) is read, and outputs a diagnostic completion marker to indicate whether there is a diagnostic opportunity between the previous read and the current read of the diagnostic result by capturing the diagnostic completion marker as high during a period in which the diagnosis of the output state of the load driver circuit (102) is performed and deleting the captured diagnostic completion marker so that it is low when the control circuit (104) is read. [9] Electronic control unit according to claim 2, wherein the control circuit (104) continues to perform normal control of the load driver circuit (102) when a final determination result of the output state of the load driver circuit (102) based on the diagnostic result and the diagnostic completion marker is normal, and the load driver circuit (102) stops when the final determination result is anomalous. [10] Electronic control unit according to claim 1, wherein the diagnostic circuit (103) sends the diagnostic result and the diagnostic completion marker to the control circuit (104) via serial communication. [11] Electronic control unit according to claim 10, wherein the diagnostic result and the diagnostic completion marker are sent to the control circuit (104) in the same frame. [12] Electronic control unit according to claim 2, wherein the control circuit (104) switches a warning light on and off when a final determination result of the output state of the load driver circuit (102) based on the diagnostic result and the diagnostic completion marker is anomalous. [13] Electronic control unit according to claim 1, wherein the control circuit (104) controls the load driver circuit (102) such that the diagnostic circuit (103) can perform the diagnosis of the output state of the load driver circuit (102) when the diagnostic termination marker indicates that there is no diagnostic period during a predetermined period or longer. [14] Electronic control unit according to claim 1, wherein the load driver circuit controls an ignition electrode (803). [15] Electronic control unit according to claim 1, wherein the load driver circuit controls a relay (903).

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