JP7318579B2 - electronic controller - Google Patents

Description

The present invention relates to electronic control units.

For example, an electronic control unit mounted on a vehicle has a power supply circuit. This power supply circuit generates a plurality of power supplies for supplying power to the microcomputer and peripheral circuits according to the power supply from the vehicle battery. Since the power supply voltage output from these power supplies must be at a predetermined rated value, the power supply circuit is equipped with a power supply monitoring circuit that monitors whether the power supply voltage is at the rated value.

In the power supply monitoring circuit, for example, the power supply voltage generated by the power supply circuit at power-on is compared with the reference voltage range by a voltage comparator, and if the power supply voltage is out of the reference voltage range, it is judged to be abnormal. This monitors whether the power generated by the power supply circuit is normal.

JP 2017-142706 A

By the way, if the comparator for voltage comparison fails, it becomes impossible to monitor the power supply voltage output from the power supply circuit. Test) function is provided. In the BIST function, when the comparator for voltage comparison determines that there is an abnormality, the abnormality determination is confirmed by one determination.

However, since relatively large electrical noise is generated, for example, when the engine is started, the configuration in which the abnormality is determined based on one abnormality determination by the BIST function does not have robustness against erroneous diagnosis due to electrical noise. There is the problem of low As for the BIST function, not only the abnormality of the comparator for voltage comparison but also the abnormality of the logic circuit constituting the power supply circuit may be monitored, and the same problem arises.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic control device capable of enhancing robustness against erroneous diagnosis when diagnosing whether a circuit to be diagnosed that constitutes a power supply circuit is normal. to provide.

According to the first aspect of the invention, the power supply circuit (12) generates a plurality of power supplies according to the power supplied from the vehicle battery (2). A control circuit (13) controls a controlled object in accordance with power supply from a power supply generated by the power supply circuit. If the power supply voltage is abnormal, the object to be controlled cannot be controlled, so the power supply monitoring circuit (18) monitors the power supply circuit. A unit (23) diagnoses whether a diagnosis target circuit (20) constituting a power supply monitoring circuit functions normally.
Here, when the diagnosis target circuit is determined to be abnormal, the diagnostic unit re-executes the diagnosis for the same diagnostic target circuit, and when it is determined to be abnormal for a predetermined number of times in succession, it finally determines that there is an abnormality. judge. When re-diagnosing, the diagnosing unit only performs the diagnosis on the circuit to be diagnosed that is determined to be abnormal.

1 is a functional block diagram showing the configuration of a power supply circuit according to a first embodiment; FIG. Schematic diagram of ECU Diagram showing diagnostic operation for normal determination (part 1) Diagram showing diagnostic operation when determining normality (part 2) Diagram showing diagnostic operation when determining normality (No. 3) Diagram showing diagnostic operation when determining abnormality Timing diagram showing BIST diagnosis timing FIG. 4 is a timing chart showing BIST diagnosis timing according to the second embodiment; Timing chart showing BIST diagnosis timing according to the third embodiment FIG. 11 is a timing chart showing BIST diagnosis timing according to the fourth embodiment; A diagram showing diagnostic operation when determining an abnormality according to the fifth embodiment.

(First embodiment)
A first embodiment applied to an ECU (Electronic Control Unit) mounted on a vehicle will be described below with reference to FIGS. 1 to 7. FIG.
The ECU 1 shown in FIG. 2 controls, for example, an engine mounted on a vehicle. The ECU 1 has a BATT terminal 3 and a +B terminal 4 as power supply terminals for receiving power from the vehicle battery 2 . The BATT terminal 3 is directly connected to the +B power supply on the positive side of the vehicle battery 2 . The +B terminal 4 is connected to the +B power supply through the switch 6 of the main relay 5 . The ECU 1 corresponds to an electronic control unit.

The ECU 1 has a J1 terminal 7 , a J2 terminal 8 and a J3 terminal 9 in addition to the BATT terminal 3 and the +B terminal 4 . The J1 terminal 7 is directly connected to the +B power supply. The J2 terminal 8 is grounded through the coil 10 of the main relay 5 . The J3 terminal 9 is connected to the +B power supply via a switch 11 that is turned on by an ignition switch. The ON state of the switch 11 is not limited to a vehicle having an engine, but includes, for example, the power ON state of an electric vehicle or a hybrid vehicle.

The ECU 1 includes a power supply circuit 12, a microcomputer 13, and a relay control circuit 14. The microcomputer 13 corresponds to the control circuit. The microcomputer is hereinafter referred to as a microcomputer.

The input terminal of the power supply circuit 12 is connected to the BATT terminal 3 and the +B terminal 4, and power can be supplied from the +B power supply via these terminals 3 and 4. The power supply circuit 12 generates a plurality of power supplies according to power supply from the +B power supply. In this embodiment, VOM5, VOM1, VOS5, and VOS1 are set as power sources. The voltages and uses of these power sources VOM5, VOM1, VOS5 and VOS1 are defined as follows.

(1) VOM5 (5V): main power supply for microcomputer 13 and relay control circuit 14 (2) VOM1 (1.2V): main power supply for core that configures microcomputer 13 (3) VOS5 (5V): for relay control circuit 14 Standby power supply (4) VOS1 (1.2V): Standby power supply for microcomputer 13

The power supply circuit 12 has a so-called power-on reset function of outputting a reset signal to the microcomputer 13 until the power supply voltage stabilizes after starting to output the VOM 5 upon receiving power from the +B power supply. The microcomputer 13 includes a CPU, ROM, RAM, etc. (not shown), and executes various control programs stored in the ROM for controlling the engine.

The relay control circuit 14 has an input circuit 15 , an OR circuit 16 and a switching element 17 . The input terminal of the input circuit 15 is connected to the J3 terminal 9 and the output terminal is connected to the input terminal of the microcomputer 13 . The input terminal of the OR circuit 16 is connected to the input circuit 15 and the output terminals of the microcomputer 13 . One end of the switching element 17 is connected to the J1 terminal 7 and the other end is connected to the J2 terminal 8 . The switching element 17 is ON/OFF controlled according to the output from the OR circuit 16 .

Since the output voltages of the power supplies VOM5, VOM1, VOS5, and VOS1 are defined to be predetermined rated values, the power supply circuit 12 is provided with a power supply monitoring circuit 18. FIG. This power supply monitoring circuit 18 monitors whether the power supply voltages of the power supplies VOM5, VOM1, VOS5 and VOS1 are within a predetermined reference voltage range.

As shown in FIG. 1, the power supply monitoring circuit 18 includes a group of switches 19 for individually switching the inputs of the power supplies VOM5, VOM1, VOS5, and VOS1, a group of comparators 20 connected to the group of switches 19, and a group of comparators 20 connected to the group of switches 19. A detection filter group 21, an AND circuit 22, and a BIST control circuit 23 are connected. The comparator group 20 corresponds to a diagnostic target circuit.

The switch group 19 is composed of a first input switch 19a to a fourth input switch 19d. The comparator group 20 is composed of a first comparator 20a to a fourth comparator 20d. The detection filter group 21 is composed of a first detection filter 21a to a fourth detection filter 21d.

The "0" side input terminals of the input switches 19a-19d are connected to the power supplies VOM5, VOM1, VOS5 and VOS1, respectively, and the output terminals are connected to the input terminals of the comparators 20a-20d, respectively. Output terminals of the respective comparators 20a-20d are connected to respective detection filters 21a-21d.

When the "0" side input terminals and output terminals of the input switches 19a-19d are connected, the power supply voltages of the power supplies VOM5, VOM1, VOS5 and VOS1 are supplied to the input terminals of the comparators 20a-20d.

Each of the comparators 20a to 20d compares the power supply voltages of the power supplies VOM5, VOM1, VOS5 and VOS1 with preset reference voltage ranges, and outputs the comparison results. The reference voltage range set for each of the comparators 20a to 20d is set to different values according to the power supplies VOM5, VOM1, VOS5 and VOS1. An upper threshold and a lower threshold are set in the reference voltage range.

Each of the comparators 20a to 20d is composed of an upper limit comparator and a lower limit comparator. When the power supply voltage is between the upper limit threshold and the lower limit threshold, the comparators 20a to 20d output "1" indicating normality. be.
The detection filters 21a-21d have a function of stably outputting the outputs from the comparators 20a-20d.

Output terminals of the detection filters 21 a to 21 d are connected to input terminals of the AND circuit 22 . The AND circuit 22 outputs "1" to the microcomputer 13 indicating that the power supply is normal when all the outputs from the detection filters 21a to 21d are "1". On the other hand, when the output from any of the detection filters 21a to 21d is "0", it outputs "0" indicating that the power supply is abnormal.

The microcomputer 13 determines that all the power supplies are normal when the output from the AND circuit 22 is "1", and determines that one of the power supplies is abnormal when the output is "0", and notifies the abnormality. . In this manner, the microcomputer 13 can monitor each of the power supplies VOM5, VOM1, VOS5 and VOS1.

By the way, the power supply monitor circuit 18 cannot normally monitor the power supplies VOM5, VOM1, VOS5, and VOS1 when an abnormality occurs in the comparators 20a to 20d for voltage comparison. Therefore, the power supply monitoring circuit 18 is provided with a BIST control circuit 23 that determines whether the comparators 20a to 20d are normal. The BIST control circuit 23 corresponds to the diagnosis section.

The BIST control circuit 23 is configured to time-divisionally diagnose the comparators 20a to 20d. That is, the BIST control circuit 23 can individually switch the input switches 19a to 19d from the "0" side input terminal to the "1" side input terminal. The output terminal of the BIST control circuit 23 is commonly connected to the "1" side input terminals of the input switches 19a to 19d. The input terminal of the BIST control circuit 23 is connected to the output terminals of the detection filters 21a to 21d.

When diagnosing each of the comparators 20a to 20d, the BIST control circuit 23 sequentially switches the input switches 19a to 19d from the "0" side input terminal to the "1" side input terminal in a time division manner, and switches the switched input switch 19a. 19d is output to the input terminal on the "1" side.

When the comparators 20a to 20d to be diagnosed are normal, the outputs from the comparators 20a to 20d are "1", so the corresponding detection filters 21a to 21d output "1". Thereby, the BIST control circuit 23 determines that the comparators 20a to 20d to be diagnosed are normal. On the other hand, when the comparators 20a to 20d to be diagnosed are abnormal, the outputs from the comparators 20a to 20d are "0", so the corresponding detection filters 21a to 21d output "0". Thereby, the BIST control circuit 23 determines that the comparators 20a to 20d to be diagnosed are abnormal.
As described above, the BIST control circuit 23 can sequentially diagnose the comparators 20a to 20d to be diagnosed.

Now, since a relatively large amount of electrical noise is generated when the engine is started, the configuration in which the BIST control circuit 23 confirms an abnormality based on a single abnormality determination does not provide robustness against erroneous diagnosis due to electrical noise. is low. Therefore, in the present embodiment, when the same comparators 20a to 20d are judged to be abnormal four times, for example, it is finally judged to be abnormal.

Specifically, as shown in FIG. 3, the first comparator 20a, the second comparator 20b, the third comparator 20c, and the fourth comparator 20d are diagnosed in order, and all the comparators 20a to 20d are normal. is finally determined to be normal. In this case, the next diagnosis will be the first diagnosis. That is, when all the comparators 20a to 20d are normal, each diagnosis is the first diagnosis.

As shown in FIG. 4, although the second comparator 20b is determined to be abnormal in the first diagnosis, if it is determined to be normal in the second diagnosis, it is finally determined to be normal. Incidentally, if the other comparator is determined to be abnormal in the second diagnosis, the diagnosis is the first diagnosis, so the second diagnosis is performed next.

As shown in FIG. 5, although the second comparator 20b is continuously determined to be abnormal in the first and second diagnostics, when it is determined to be normal in the third diagnostic, it is finally determined to be normal.
As shown in FIG. 6, when the second comparator 20b is continuously judged to be abnormal in the first to fourth diagnoses, it is finally judged to be abnormal.

Since the microcomputer 13 cannot perform normal voltage monitoring during the diagnosis by the BIST control circuit 23 described above, it is desirable to execute the diagnosis outside the processing period of the microcomputer 13 . Therefore, diagnosis of the comparators 20a to 20d by the BIST control circuit 23 is performed outside the processing period of the microcomputer 13. FIG.

Specifically, as shown in FIG. 7, when the switch 11 is turned ON in response to the ON operation of the ignition switch, the switching element 17 of the relay control circuit 14 is accordingly turned ON, so that the coil 10 of the main relay 5 is energized. switch 6 is turned on. Then, power is supplied from the +B power supply to the power supply circuit 12 through the switch 6, so that the power supply circuit 12 supplies power to the microcomputer 13 in addition to the power supply VOS1, which is a standby power supply, and the power supply VOM5. At this time, since the microcomputer 13 is reset by the power supply circuit 12, the microcomputer 13 will not start.

The BIST control circuit 23 diagnoses the comparators 20a to 20d of the power supply circuit 12 in order when activated in response to the power supply VOM5 being supplied from the power supply circuit 12. FIG.
Since the power supply circuit 12 releases the reset to the microcomputer 13 when the power supply VOM5 is stabilized, the microcomputer 13 is activated to start the engine. Although a large amount of electrical noise is generated when the engine is started, the diagnosis of the comparators 20a to 20d has been completed, so the diagnosis can be reliably performed without being affected by the electrical noise when the engine is started.

Then, when the switch 11 is turned off in response to the ignition switch being turned off, the microcomputer 13 keeps the main relay 5 in the on state in order to perform post-processing. Thereby, the power supply state of the power supply VOM5 from the power supply circuit 12 to the microcomputer 13 is maintained. When all the processes are completed, the microcomputer 13 turns off the main relay 5, so that the power supply VOM5 from the power supply circuit 12 to the microcomputer 13 is stopped. As a result, only the power supply VOS1 is supplied to the microcomputer 13, so that the microcomputer 13 enters a standby state.

According to such an embodiment, the following effects can be obtained.
Since the BIST control circuit 23 finally determines that the comparators 20a to 20d are abnormal when the same comparators 20a to 20d are determined to be abnormal four times in succession during the diagnosis of the comparators 20a to 20d, robustness against erroneous diagnosis due to electrical noise is ensured. can be enhanced.

Since the diagnosis of the comparators 20a to 20d is performed after the power supply circuit 12 is activated and before the microcomputer 13 is activated, the diagnosis can be performed before the engine is started, thereby further enhancing robustness.

(Second embodiment)
A second embodiment will be described with reference to FIG. This second embodiment is characterized in that diagnosis of the comparators 20a to 20d is performed after all the processing of the microcomputer 13 is completed.

As described above, the diagnosis can be performed before the microcomputer 13 is started by executing the diagnosis when the power supply circuit 12 is started. Therefore, as shown in FIG. 8, the diagnosis is performed after the microcomputer 13 completes all the processing, thereby diagnosing without affecting the processing of the microcomputer 13 .

When the switch 11 is turned off, the microcomputer 13 keeps the switch 6 on to execute post-processing, and when all the processing is completed, notifies the power supply circuit 12 of the end of the processing. The BIST control circuit 23 of the power supply circuit 12 diagnoses the comparators 20a to 20d when receiving a notification of the end of processing from the microcomputer 13. FIG. Then, the microcomputer 13 turns off the main relay 5 when receiving the diagnosis result from the BIST control circuit 23 .

According to this embodiment, the BIST control circuit 23 diagnoses the comparators 20a to 20d after the microcomputer 13 completes all processing and before the main relay 5 is turned off. Diagnosis can be performed reliably without affecting control.

(Third embodiment)
A third embodiment will be described with reference to FIG. This third embodiment is characterized in that the diagnosis of the comparators 20a to 20d by the BIST control circuit 23 is re-executed.
As shown in FIG. 9, the BIST control circuit 23 executes the diagnosis before starting the microcomputer 13 by executing the diagnosis when the power supply circuit 12 is started as described in the first embodiment. However, as described above, the power supply circuit 12 is easily affected by electrical noise immediately after the power supply circuit 12 is started. Upon termination, the diagnosis of the comparators 20a to 20d is re-executed.

According to this embodiment, when the power supply circuit 12 is diagnosed as being abnormal at startup, the microcomputer 13 completes all the processing and then executes the diagnosis again. The robustness against erroneous diagnosis due to electrical noise can be further enhanced while reliably diagnosing without influence.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIG. This fourth embodiment is characterized in that the diagnosis of the comparators 20a to 20d is repeatedly executed.
As shown in FIG. 10, the BIST control circuit 23 repeatedly diagnoses the comparators 20a to 20d a plurality of times during the period from when the power supply circuit 12 is activated until when the microcomputer 13 is activated.

According to this embodiment, the BIST control circuit 23 repeatedly diagnoses the comparators 20a to 20d from the start of the power supply circuit 12 until the microcomputer 13 starts up. This makes the diagnosis more robust against electrical noise at times.
In the second embodiment and the third embodiment, the diagnosis to be executed after the microcomputer 13 has finished all the processes may be repeatedly executed.

(Fifth embodiment)
A fifth embodiment will be described with reference to FIG. This fourth embodiment is characterized in that when the comparators 20a to 20d are diagnosed as abnormal, the diagnosis is limited to the comparators 20a to 20d that are determined to be abnormal and re-executed.

As shown in FIG. 11, when the BIST control circuit 23 determines that there is an abnormality in the first diagnosis, the BIST control circuit 23 re-executes the diagnosis limited to the comparators 20a to 20d that have been determined to be abnormal, and determines that there is an abnormality four times in a row. If it does, it is finally judged to be abnormal.

According to such an embodiment, when the BIST control circuit 23 determines that there is an abnormality, the BIST control circuit 23 re-executes the diagnosis only for the comparators 20a to 20d that have been determined to be abnormal, thereby simplifying the diagnosis and shortening the diagnosis time. can be achieved.

(Other embodiments)
The number of execution times for diagnosing the comparators 20a to 20d is not limited to four, and may be executed any number of times as long as it is two or more times.
The comparators 20a to 20d may have a learning function so that the number of diagnoses is increased when the comparators 20a to 20d are judged to be abnormal, and the number of diagnoses is reduced when the comparators 20a to 20d are judged to be normal.
The diagnosis object circuit of the power supply circuit 12 is not limited to the comparators 20a to 20d for voltage comparison, and an abnormality of a digital circuit forming the power supply circuit 12 may be diagnosed.

Although the present disclosure has been described with reference to embodiments, it is understood that the present disclosure is not limited to such embodiments or structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and configurations, as well as other combinations and configurations, including single elements, more, or less, are within the scope and spirit of this disclosure.

In the drawings, 1 is an ECU (electronic control unit), 5 is a main relay, 12 is a power supply circuit, 13 is a microcomputer (control circuit), 18 is a power supply monitoring circuit, 20 is a comparator group (diagnosis target circuit), and 23 is BIST control. This is the circuit (diagnosis section).

Claims (8)

a power supply circuit (12) that generates a plurality of power supplies according to power supply from an in-vehicle battery (2);
a control circuit (13) for controlling a controlled object according to power supply from the power supply generated by the power supply circuit;
a power monitoring circuit (18) for monitoring the power circuit;
a diagnostic unit (23) for diagnosing whether the diagnostic target circuit (20) constituting the power supply monitoring circuit functions normally,
The diagnosing unit re-executes the diagnosis for the same circuit to be diagnosed when it is determined that the circuit to be diagnosed is abnormal, and finally determines that the circuit to be diagnosed is abnormal when it is determined to be abnormal a predetermined number of times in succession. judge ,
The diagnosing unit, when re-executing the diagnosis, executes the diagnosis only on the circuit to be diagnosed that is determined to be abnormal . a power supply circuit (12) that generates a plurality of power supplies according to power supply from an in-vehicle battery (2);
a control circuit (13) for controlling a controlled object according to power supply from the power supply generated by the power supply circuit;
a power monitoring circuit (18) for monitoring the power circuit;
a diagnostic unit (23) for diagnosing whether the diagnostic target circuit (20) constituting the power supply monitoring circuit functions normally,
The diagnosing unit re-executes the diagnosis for the same circuit to be diagnosed when it is determined that the circuit to be diagnosed is abnormal, and finally determines that the circuit to be diagnosed is abnormal when it is determined to be abnormal a predetermined number of times in succession. judge ,
The diagnosis unit executes the diagnosis outside the processing operation period of the control circuit,
Equipped with only one main relay (5) that supplies power from the on-board battery in the ON state,
The diagnosing unit is an electronic control unit that executes the diagnosis from the end timing of the process for the controlled object until the one main relay is turned off. a power supply circuit (12) that generates a plurality of power supplies according to power supply from an in-vehicle battery (2);
a control circuit (13) for controlling a controlled object according to power supply from the power supply generated by the power supply circuit;
a power monitoring circuit (18) for monitoring the power circuit;
a diagnostic unit (23) for diagnosing whether the diagnostic target circuit (20) constituting the power supply monitoring circuit functions normally,
The diagnosing unit re-executes the diagnosis for the same circuit to be diagnosed when it is determined that the circuit to be diagnosed is abnormal, and finally determines that the circuit to be diagnosed is abnormal when it is determined to be abnormal a predetermined number of times in succession. judge ,
The diagnosis unit executes the diagnosis outside the processing operation period of the control circuit,
Equipped with only one main relay (5) that supplies power from the on-board battery in the ON state,
The diagnosis unit executes the diagnosis between the start timing of the power supply circuit and the start timing of the control circuit, and turns off the one main relay from the end timing of the process for the controlled object when an abnormality is determined. An electronic controller that reruns the diagnostics until the 2. The electronic control device according to claim 1, wherein the diagnosis section executes the diagnosis outside the processing operation period of the control circuit. The electronic control device according to any one of claims 2 to 4, wherein the diagnosis section executes the diagnosis between the activation timing of the power supply circuit and the activation timing of the control circuit. The electronic control device according to any one of claims 2 to 4, wherein the diagnosis unit repeatedly performs the diagnosis outside the processing operation period of the power supply circuit. Equipped with a main relay (5) that supplies power from an on-board battery in the ON state,
5. The electronic control device according to claim 4, wherein the diagnosis section executes the diagnosis between the end timing of processing for the controlled object and the end timing of control of the main relay. Equipped with a main relay (5) that supplies power from an on-board battery in the ON state,
The diagnosing unit executes the diagnosis between the start timing of the power supply circuit and the start timing of the control circuit, and if it is determined that there is an abnormality, the diagnosis unit starts from the end timing of the process for the controlled object and the end timing of the control of the main relay. 5. The electronic control unit according to claim 4, wherein the diagnosis is re-executed until.

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