Electronic Control Devices

Abstract

According to the present invention, even when the power relay cannot be turned off and the power supply to the microcomputer is normally cut off, the sticking of the power relay can be detected. An electronic control device (100) of one embodiment of the present invention includes: a relay drive circuit (13), which is used to control the connection or disconnection of the power relay (12) according to the information of the power on or off; an electronic circuit (first power system module (110), a microcomputer (102)), which uses the first power supply voltage (V1) supplied from the battery (10) via the power relay (12) to work; and a monitoring unit (second power system module (120)), which monitors the first power supply voltage when the power is turned off, which can reflect whether the sticking of the power relay occurs, and saves the monitoring result.

Description

Technical Field

[0001] The present invention relates to an electronic control device having a function of detecting an abnormality of a power supply relay for turning on and off the supply of a power supply voltage. Background Art

[0002] In the past, as an electronic control device for controlling a vehicle, there is an electronic control device that outputs a signal from the electronic control device itself (power relay drive circuit), and the signal is used to control the conduction state of the power relay used to supply power to the electronic control device from the battery. In this case, when the user of the vehicle turns on the ignition switch, the power relay drive circuit installed in the electronic control device is turned on, and the power relay is turned on. When the user turns off the ignition switch, the power relay drive circuit is turned off, and the power relay is turned off, thereby stopping the power supply to the electronic control device.

[0003] In the above-mentioned power relay, when the power relay remains on and cannot be turned off, the so-called on-stick abnormality occurs, and the power relay continues to be on even after the user turns off the ignition switch. In this way, the power supply voltage continues to be supplied from the vehicle battery to the electronic control device, which seems to the user as an increase in dark current, causing battery failure.

[0004] Therefore, it is required to set an abnormality detection function for detecting the abnormal connection of the power relay in the electronic control device, and remind the user to implement certain measures when the abnormal connection occurs. For example, Patent Document 1 records an electronic control device that measures the number of times a microcomputer (hereinafter referred to as "microcomputer") is started when the ignition switch is turned off, and determines whether the abnormal connection of the power relay has occurred based on the measured value.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2015-217911 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, the electronic control device described in Patent Document 1 assumes that the microcomputer continues to be powered even when the power relay cannot be turned off. Therefore, a solution is required to detect the sticking of the power relay and notify the user when the power supply to the microcomputer is normally cut off even though the power relay is not turned off when the ignition switch is turned off.

[0010] In view of the above circumstances, an object of the present invention is to detect sticking of a power relay even when the power relay cannot be turned off and the power supply to a microcomputer is cut off.

[0011] Technical solutions to solve problems

[0012] In order to solve the above-mentioned problems, an electronic control device of one embodiment of the present invention includes: a relay driving circuit, which is used to control the connection or disconnection of a power relay according to the information of whether the power is connected or disconnected; an electronic circuit, which operates using a first power supply voltage supplied from a battery via a power relay; and a monitoring unit, which monitors the first power supply voltage when the power is turned off, which can reflect whether adhesion of the power relay occurs, and saves the monitoring results.

[0013] Effects of the Invention

[0014] According to at least one embodiment of the present invention, even when the power relay cannot be turned off and the power supply to the monitoring unit is normally cut off, sticking of the power relay can be detected based on the monitoring result of the first power supply voltage reflecting whether sticking of the power relay occurs.

[0015] The problems, structures, and effects other than those described above will be explained through the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a block diagram showing an example of the configuration of an electronic control device according to the first embodiment of the present invention.

[0017] Figure 2 It is a diagram showing an example of the configuration of a relay drive circuit included in the electronic control device according to the first embodiment of the present invention.

[0018] Figure 3 It is a diagram showing an example of the configuration of a voltage detection circuit included in the electronic control device according to the first embodiment of the present invention.

[0019] Figure 4 This is a diagram showing an example of the configuration of a register included in the electronic control device according to the first embodiment of the present invention.

[0020] Figure 5 This is a timing chart showing an example of the operation when the power supply relay does not have on-sticking in the electronic control device according to the first embodiment of the present invention.

[0021] Figure 6 This is a timing chart showing an example of the operation when the power supply relay is stuck in the electronic control device according to the first embodiment of the present invention.

[0022] Figure 7This is a block diagram showing an example of the configuration of an electronic control device according to the second embodiment of the present invention.

[0023] Figure 8 This is a timing chart showing an example of the operation when the power supply relay does not have on-sticking in the electronic control device according to the second embodiment of the present invention.

[0024] Fig. 9 This is a timing chart showing an example of the operation when the power supply relay is stuck in the electronic control device according to the second embodiment of the present invention.

[0025] Fig.10 This is a block diagram showing an example of the configuration of an electronic control device according to a third embodiment of the present invention.

[0026] Fig.11 This is a block diagram showing an example of the configuration of a timer circuit included in an electronic control device according to a third embodiment of the present invention.

[0027] Fig.12 This is a block diagram showing an example of the configuration of a count comparison circuit included in a timer circuit according to a third embodiment of the present invention.

[0028] Fig.13 This is a timing chart showing an example of the operation when the power supply relay does not have on-sticking in the electronic control device according to the third embodiment of the present invention.

[0029] Fig.14 The electronic control device according to the third embodiment of the present invention is operated when the power supply relay does not have on-sticking. Fig.13 Timing diagrams for different examples.

[0030] Fig.15 This is a timing chart showing an example of the operation when the power supply relay is stuck in the electronic control device according to the third embodiment of the present invention.

[0031] Fig.16 This is a timing chart showing another example of the operation when the power supply relay is stuck in the electronic control device according to the modified example of the third embodiment of the present invention. DETAILED DESCRIPTION

[0032] Hereinafter, examples of modes for implementing the present invention (hereinafter referred to as "embodiments") will be described with reference to the drawings. In this specification and the drawings, components having substantially the same function or structure are denoted by the same reference numerals, and repeated descriptions are omitted.

[0033] <1. First embodiment>

[0034] First, the structure of the electronic control device according to the first embodiment of the present invention will be described.

[0035] Figure 1 It is a block diagram showing an example of the configuration of the electronic control device 100 according to the first embodiment. Figure 1 The electronic control device 100 shown is configured to detect the sticking of the contact 12b of the power relay 12. The power relay 12 may be either a mechanical type or a semiconductor type. In this specification, the sticking of the contact 12b of the power relay 12 is described as "the power relay 12 sticks". In addition, in the following description, the on (closed) / off (open-closed) of the contact 12b of the power relay 12 is described as "the power relay 12 is on / off".

[0036] The electronic control device 100 has a terminal BATT to which the power supply voltage VBAT (second power supply voltage) generated by the battery 10 is directly supplied, a terminal VB to which the power supply voltage VBAT (first power supply voltage) is supplied via the contact 12b of the power supply relay 12, a terminal MRD connected to the other end (coil 12a) of the power supply relay 12, and a terminal PSA to which the power supply voltage VBAT is supplied when the ignition switch 11 is turned on. The electronic control device 100 is, for example, an ECU (Electronic Control Unit). By turning the ignition switch 11 on / off, the power supply corresponding to the relay drive circuit 13 is turned on / off.

[0037] In this specification, in order to simplify the description, the names of the wirings connected to the respective terminals of the electronic control device 100 are made the same as the names of the terminals. For example, the wiring connected to the terminal VB is referred to as the wiring VB.

[0038] In addition, the electronic control device 100 includes a power supply IC 101 and a microcomputer 102. The power supply IC 101 includes a relay drive circuit 13 for controlling the on or off of the power supply relay 12, a first power supply circuit 21 for generating an internal voltage V1 (first internal voltage) for internal supply to the electronic control device 100, and a second power supply circuit 22 for generating an internal voltage V2 (second internal voltage) for internal supply to the electronic control device 100. In addition, the power supply IC 101 includes a first power supply system module 110 which is a circuit module that operates by powering with the internal voltage V1, and a second power supply system module 120 which is a circuit module that operates by powering with the internal voltage V2.

[0039] In this embodiment, for example, the second power supply system module 120 has a voltage detection circuit 30 for detecting the voltage of the wiring connected to the terminal VB, and a register 31 for storing the detection result of the voltage detection circuit 30. The voltage detection circuit 30 and the register 31 are an example of a monitoring unit. In addition, for example, the first power supply system module 110 has a communication circuit 40 for writing and reading data to and from the register 31 according to an instruction from the microcomputer 102.

[0040] The relay drive circuit 31 uses the wiring connected to the terminal PSA as input and the wiring connected to the terminal MRD as output. When the power supply voltage VBAT is supplied via the terminal PSA, the relay drive circuit 13 makes the potential of the wiring connected to the terminal MRD equal to the ground level and controls the power relay 12 to be in the on state. In addition, when the power supply voltage VBAT is not supplied via the terminal PSA, the relay drive circuit 13 has a function of keeping the potential of the wiring connected to the terminal MRD at the power supply voltage VBAT and controlling the power relay 12 to be in the off state.

[0041] Figure 2 An example of the configuration of the relay drive circuit 13 is shown.

[0042] The relay driving circuit 13 can be formed using a switching element 131 such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Figure 2 This is an example of using an N-channel MOSFET as the switching element 131. The gate of the switching element 131 is connected to the terminal PSA, the drain is connected to the terminal MRD, and the source is grounded. When the power supply voltage VBAT is supplied to the gate via the terminal PSA, the drain-source becomes conductive (ON), current flows through the coil 12a, and the contact 12b is turned on. On the other hand, when the power supply voltage VBAT is not supplied to the gate, the drain-source becomes non-conductive (OFF), no current flows through the coil 12a, and the contact 12b is turned off. In addition, Figure 2 The example is for explaining the basic function of the relay drive circuit 13, and is not limited to this structure.

[0043] The first power supply circuit 21 is characterized in that the power supply voltage VBAT supplied from the terminal VB is input, and its operation is controlled according to whether the power supply voltage VBAT is applied via the terminal PSA. The first power supply circuit 21 has a function of outputting the internal voltage V1 to the second power supply system module 120 and the microcomputer 102 when the power supply voltage VBAT is supplied via the terminal VB or the power supply voltage VBAT is applied via the terminal PSA. In addition, the first power supply circuit 21 has a function of not outputting the internal voltage V1 when the power supply voltage VBAT is not supplied via the terminal VB or the power supply voltage VBAT is not applied via the terminal PSA.

[0044] The second power supply circuit 22 has a function of taking the power supply voltage VBAT supplied via the terminal BATT as an input and outputting the internal voltage V2 to the second power supply system module 120. When the power supply voltage VBAT is not input, the internal voltage V2 is not output. In this way, the second power supply circuit 22 operates using the power supply voltage VBAT directly supplied from the battery 10 through a path (terminal BATT) that does not pass through the power relay 12. Therefore, the power supply voltage VBAT is supplied to the second power supply circuit 22 regardless of whether the power relay 12 is turned on / off.

[0045] The voltage detection circuit 30 has a function of outputting the result of detecting the power supply voltage VBAT supplied from the terminal VB as VBdet. The voltage level of VBdet is a binary value of a high level (hereinafter referred to as "H level") or a low level (hereinafter referred to as "L level").

[0046] Figure 3 An example of the configuration of the voltage detection circuit 30 is shown.

[0047] For example, the voltage detection circuit 30 is composed of a comparator 301 and a constant voltage circuit that generates a threshold voltage VBth. The wiring VB is connected to the non-inverting input terminal (+ terminal) of the comparator 301, and the threshold voltage VBth is input to the inverting input terminal (- terminal) of the comparator 301. When the power supply voltage VBAT (first power supply voltage) input from the terminal VB is greater than the threshold voltage VBth, the comparator 301 outputs an H-level voltage detection result VBdet.

[0048] The communication circuit 40 is connected to the microcomputer 102 and the register 31 , and has a function of writing binary information of H level or L level to the register 31 according to an instruction from the microcomputer 102 , or reading binary information stored in the register 31 and sending it to the microcomputer 102 .

[0049] The register 31 (an example of a storage unit) is connected to the voltage detection circuit 30 and the communication circuit 40, and when the output VBdet of the voltage detection circuit 30 is at the H level, stores the binary information written from the microcomputer 102 via the communication circuit 40. In addition, when the output VBdet of the voltage detection circuit 30 is at the L level, the register 31 always stores only the information at the L level.

[0050] Figure 4 An example of the structure of the register 31 is shown.

[0051] The register 31 is constituted by, for example, a D flip-flop 311. Data written from the microcomputer 102 via the communication circuit 40 is input to the input terminal D of the D flip-flop 311, and the stored data is output from the output terminal Q. The output VBdet of the comparator 301 is input to the reset terminal RN of the D flip-flop 311. The reset terminal RN is an inverting input. A clock signal generated by, for example, the second power supply system module 120 is input to the clock terminal.

[0052] During the period when the reset terminal RN is input with an L level signal, the D flip-flop 311 is in a reset state, and the stored value is always at an L level. During the period when the reset terminal RN is input with an H level signal, the D flip-flop 311 is in a non-reset state, and in this embodiment, the H level or L level data written from the microcomputer 102 via the communication circuit 40 is stored.

[0053] In this way, register 31 (an example of a storage unit) is configured to store and output information written by a processor (processor 102a), and the stored information is reset and a low-level signal is output by inverting a low-level signal output by a voltage detection circuit (voltage detection circuit 30) to obtain a signal.

[0054] The microcomputer 102 operates when the internal voltage V1 is supplied from the first power supply circuit 21, and has a function of writing binary information to the register 31 via the communication circuit 40, or reading binary information from the register 31. The microcomputer 102 has a processor 102a such as a CPU, a memory 102b such as a RAM and a ROM, etc. The processor 102a is the main body of the operation of the microcomputer 102. A noise elimination circuit is often provided between the microcomputer 102 and the wiring for supplying the internal voltage V1.

[0055] When the power supply voltage continues to be supplied from the battery 10 to the terminal VB even after the ignition switch 11 is turned off (the power supply IC 101 is shut down) due to the sticking of the power supply relay 12, the value of the register 31 storing the detection result of the voltage detection circuit 30 is saved. Therefore, after the ignition switch 11 is turned on again, the microcomputer 102 can read the register value and detect the sticking of the power supply relay 12.

[0056] [Operation when the power relay is not stuck]

[0057] Next, the operation of the electronic control device 100 configured as described above will be described. Figure 5 , the description will be given assuming that the power supply relay 12 can be normally controlled to be in the on or off state.

[0058] Figure 5 This is a timing diagram showing an example of the operation of the power relay 12 in the electronic control device 100 when there is no on-sticking. On-sticking means that the contact 12b of the power relay 12 sticks in the on state and does not change to the off state. Off-sticking is the opposite state. On-sticking occurs due to faults such as welding of the contacts of the power relay 12 and a ground short circuit on the output side of the relay drive circuit 13 (between the drain and source of the switching element 131). Figure 5 , an example of the operation timing of the ignition switch 11, the internal voltage V2, the voltage of the MRD terminal, the voltage of the terminal VB, VBdet, the internal voltage V1, the stored value (stored data) of the register 31, and the read value (read data) of the microcomputer 102 is shown. The horizontal axis of the timing chart represents the passage of time.

[0059] Assume that Figure 5 At the initial time t0 of the timing chart shown, the ignition switch 11 is in the off state. At this time, the potential of the terminal MRD connected to the relay drive circuit 13 is substantially equal to the power supply voltage VBAT, and the power supply relay 12 is controlled to be in the off state. In other words, the power supply voltage VBAT is not supplied to the terminal VB. At this time, the internal voltage V1 is not output from the first power supply circuit 21, and the communication circuit 40 and the microcomputer 102 are in a non-operating state.

[0060] On the other hand, the power supply voltage VBAT is supplied to the terminal BATT, and the second power supply circuit 22 outputs the internal voltage V2 and supplies it to the second power supply system module 120. At this time, the voltage detection circuit 30 and the register 31 included in the second power supply system module 120 are in an electrically operable state. However, since the power supply voltage VBAT is not supplied to the voltage detection circuit 30 via the terminal VB, the output VBdet of the voltage detection circuit 30 outputs an L level, and the register 31 becomes a reset state and stores an L level.

[0061] Consider Figure 5The ignition switch 11 is switched from off to on at time t1 shown. At this time, the power supply voltage VBAT is supplied to the terminal PSA via the ignition switch 11, the switch element 131 of the relay drive circuit 13 is turned on and current is drawn from the terminal MRD, so that the power supply relay 12 is turned on. Since the power supply relay 12 is turned on, the power supply voltage VBAT is supplied to the terminal VB, and the first power supply circuit 21 outputs the internal voltage V1. The communication circuit 40 and the microcomputer 102 receive the supply of the internal voltage V1 and start to operate.

[0062] The power supply voltage VBAT is similarly supplied to the voltage detection circuit 30. When the power supply voltage VBAT exceeds the threshold voltage VBth, the output VBdet changes from L level to H level. When the output VBdet of the voltage detection circuit 30 becomes H level, the register 31 changes from the reset state to the non-reset state.

[0063] Next, at time t2, the microcomputer 102 reads the data stored in the register 31 (D flip-flop 311) via the communication circuit 40. The stored data in the register 31 at time t2 is at an L level, and the read data is also at an L level. The microcomputer 102 performs predetermined processing such as initialization during the period from time t1 to time t2, and immediately reads data after completing the predetermined processing.

[0064] Next, at time t3 , the microcomputer 102 writes H-level data to the register 31 (D flip-flop 311 ) via the communication circuit 40 , and stores the H-level data in the register 31 .

[0065] Then, at time t4, when the ignition switch 11 is switched from on to off, the relay drive circuit 13 is turned off. Therefore, the voltage of the terminal VB (first power supply voltage) gradually decreases due to the current consumption in the electronic control device 100.

[0066] At time t5, when the voltage of the terminal VB drops below the threshold voltage VBth, the output VBdet of the voltage detection circuit 30 changes to L level. Therefore, the register 31 is reset and the data stored in the register 31 changes to L level.

[0067] After that, at time t6, the ignition switch 11 is turned on again, and the same operation as when the ignition switch 11 is turned on at time t1 is performed. At time t7, similarly to time t2, the microcomputer 102 reads L-level data from the register 31 via the communication circuit 40. Then, at time t8, the microcomputer 102 writes H-level data to the register 31 similarly to time t3 for the next adhesion detection.

[0068] [Operation when the power relay is stuck]

[0069] Next, a case where the power supply relay 12 cannot be normally controlled to the on or off state will be described.

[0070] Figure 6 1 is a timing chart showing an example of the operation when the power supply relay 12 in the electronic control device 100 is stuck. Figure 6 In the timing diagram shown in FIG. 1 , it is assumed that until time t3, Figure 5 Similarly, the power relay 12 can be controlled to be turned on or off, but the power relay 12 is stuck in the on state from time t3 to time t10. Figure 5 The examples shown are the same, so the description is omitted.

[0071] After time t3 and until time t10, when the power relay 12 is stuck in the on state, when the ignition switch 11 is switched from on to off at time t10, the power relay 12 is stuck in the on state, so the power supply voltage VBAT continues to be supplied to the terminal VB of the electronic control device 100. At this time, the power supply voltage VBAT continues to be supplied to the first power circuit 21, but the voltage application through the terminal PSA is no longer performed because the ignition switch 11 is turned off, so the first power circuit 21 stops outputting the internal voltage V1. As a result, the communication circuit 40 and the microcomputer 102 stop operating because the supply of the internal voltage V1 stops.

[0072] On the other hand, the second power supply circuit 22 receives the supply of the power supply voltage VBAT through the terminal BATT and outputs the internal voltage V2 regardless of whether the power supply relay 12 is stuck, so the voltage detection circuit 30 continues to operate and the output VBdet is stored at the H level. Therefore, the register 31 stores the H level data written from the microcomputer 102 at time t3.

[0073] When the ignition switch 11 is turned on again at time t11, the power supply voltage VBAT is applied to the first power supply circuit 21 via the terminal PSA. Then, the first power supply circuit 21 outputs the internal voltage V1 based on the power supply voltage VBA, and the communication circuit 40 and the microcomputer 102 start to operate.

[0074] At time t12, the microcomputer 102 reads the data stored in the register 31 via the communication circuit 40. Here, since the register 31 stores the H-level data, the microcomputer 102 reads the H-level data. That is, since it is assumed that the power relay 12 is stuck in the on state, the H-level data different from the L-level data read at time t2 is read. In this way, by the microcomputer 102 reading the H-level data from the register 31, the microcomputer 102 can detect that the power relay 12 is stuck in the on state.

[0075] Then, at time t13, the microcomputer 102 writes H-level data to the register 31 in the same manner as at time t8.

[0076] As described above, according to the first embodiment, it is known that the structure and method of realizing the electronic control device 100 capable of detecting the sticking of the power supply relay 12 in the on state.

[0077] (Study on the situation of power relay shutting off and sticking)

[0078] Here, for the operation of the electronic control device 100 when the power relay 12 is stuck in the OFF state and cannot be switched to the ON state due to some reason, refer to Figure 1 Provide explanation.

[0079] Although the ignition switch 11 is switched from off to on, and the power supply voltage VBAT is supplied to the relay drive circuit 13 via the terminal PSA, the power supply relay 12 is still in the off state, and the power supply voltage VBAT supplied from the battery 10 is not supplied to the terminal VB of the electronic control device 100. As a result, the first power supply circuit 21 that operates with the power supply voltage VBAT supplied via the terminal VB also becomes a state where the power supply voltage VBAT is not supplied, and the first power supply circuit 21 does not output the internal voltage V1. That is, the communication circuit 40 and the microcomputer 102 that operate by supplying the internal voltage V1 do not operate. Therefore, the operation of the electronic control device 100 described in this embodiment can be realized only when the power supply relay 12 is in the on-sticking state.

[0080] As described above, the electronic control device (electronic control device 100) of the first embodiment has: a relay drive circuit (relay drive circuit 13), which is used to control the connection or disconnection of the power relay (power relay 12) according to the information of the connection or disconnection of the power supply (ignition switch 11); an electronic circuit (first power system module 110, microcomputer 102), which uses the first power supply voltage (power supply voltage VBAT via terminal VB) supplied from the battery (battery 10) via the power relay to work; and a monitoring unit (second power system module 120), which monitors the first power supply voltage when the power is turned off, reflecting whether adhesion of the power relay occurs, and saves the monitoring results.

[0081] According to the electronic control device of the above structure, the state in which the power supply to the electronic control device cannot be cut off due to the adhesion of the power relay in the on state is detected and saved by the monitoring unit. Then, after the power is turned on, the monitoring result (read data) including the information about the adhesion of the power relay is read from the monitoring unit, and the monitoring result is notified to the user of the vehicle, thereby reminding the user to implement necessary measures. In this way, the electronic control device of this embodiment can detect the adhesion of the power relay based on the monitoring result of the first power supply voltage reflecting whether the adhesion of the power relay occurs when the power relay cannot be turned off and the power supply to the monitoring unit is normally cut off.

[0082] In addition, in the electronic control device (electronic control device 100) of the present embodiment, the monitoring unit (second power supply system module 120) has: a voltage detection circuit (voltage detection circuit 30), which outputs a signal of a level (H, L) corresponding to the voltage value of the first power supply voltage (power supply voltage VBAT via terminal VB); and a storage unit (register 31), which stores information indicating whether the first power supply voltage is reduced based on the signal output by the voltage detection circuit when the power supply (ignition switch 11) is turned off, as the above-mentioned monitoring result.

[0083] According to the electronic control device having the above configuration, by storing information indicating whether the first power supply voltage has dropped based on the signal output from the voltage detection circuit in the storage unit, the information can be output in response to an external information read request.

[0084] In addition, in the electronic control device (electronic control device 100) of the present embodiment, the electronic circuit (first power supply system module 110, microcomputer 102) has: a processor (processor 102a) that reads information indicating whether the first power supply voltage (power supply voltage VBAT via terminal VB) is reduced and stored in the storage unit (register 31), and writes the information to the above-mentioned storage unit. The processor is configured to detect the sticking abnormality of the power supply relay (power supply relay 12) based on the information read from the above-mentioned storage unit.

[0085] According to the electronic control device having the above configuration, the processor can read the information indicating whether the first power supply voltage has dropped, which is stored in the storage unit, at any timing to detect the sticking abnormality of the power supply relay.

[0086] In addition, in the electronic control device (electronic control device 100) of the present embodiment, the configuration is as follows: the voltage detection circuit (voltage detection circuit 30) compares the first power supply voltage (power supply voltage VBAT via terminal VB) with a threshold voltage (VBth), and outputs a high-level signal to the storage unit (register 31) when the first power supply voltage is greater than the threshold voltage, and outputs a low-level signal in other cases.

[0087] According to the electronic control device of the above structure, the voltage detection circuit outputs a high level signal to the storage unit when the first power supply voltage is greater than the threshold voltage, and outputs a low level signal otherwise, thereby storing information indicating a high level or information indicating a low level in the storage unit.

[0088] In addition, in the electronic control device (electronic control device 100) of the present embodiment, the configuration is as follows: the processor (processor 102a) reads the storage unit (register 31) when the power supply (ignition switch 11) is switched from off to on, and detects the adhesion abnormality of the power relay (power relay 12) based on the first read information read from the storage unit last time (time t2) and the second read information read from the storage unit this time (time t7, t12).

[0089] According to the electronic control device of the above structure, when the power is switched from off to on, the first read information last read from the storage unit is compared with the second read information read from the storage unit this time (after being turned on again), and the adhesion abnormality of the power relay is detected based on the comparison result.

[0090] In addition, in the electronic control device (electronic control device 100) of the present embodiment, the configuration is as follows: when the first read information read from the storage unit last time (time t2) is information indicating a low level and the second read information read from the storage unit this time (time t7, t12) is information indicating a high level, the processor (processor 102a) determines that a sticking abnormality has occurred in the power relay (power relay 12).

[0091] According to the electronic control device of the above structure, when the first read information read from the storage unit last time is information indicating a low level and the second read information read from the storage unit this time (after being connected again) changes to information indicating a high level, it can be determined that the first power supply voltage has not dropped to the voltage threshold, that is, a sticking abnormality of the power supply relay has occurred.

[0092] In addition, in the electronic control device (electronic control device 100) of the present embodiment, the configuration is as follows: the processor (processor 102a) reads information from the storage unit (register 31) when the power supply (ignition switch 11) changes from off to on, and after reading the information from the storage unit, writes information indicating a high level to the storage unit.

[0093] According to the electronic control device of the above structure, after reading information from the storage unit when the power changes from off to on, information indicating a high level is written to the storage unit. Therefore, the next time the power changes from off to on, the adhesion abnormality of the power relay can be detected based on the change of the information stored in the storage unit.

[0094] In addition, in the electronic control device (electronic control device 100) of the present embodiment, the monitoring unit (second power supply system module 120) operates using a second power supply voltage (power supply voltage VBAT via terminal BATT) supplied from a battery (battery 10) through a path (path via terminal BATT) that does not pass through a power supply relay (power supply relay 12).

[0095] According to the electronic control device having the above configuration, the second power supply voltage is directly supplied from the battery to the monitoring unit without being affected by the on / off (sticking) of the power relay.

[0096] <2. Second Embodiment>

[0097] In the second embodiment, another example of the structure and operation of the electronic control device capable of detecting sticking of the power supply relay 12 in the on state will be described.

[0098] Figure 7 1 is a block diagram showing an example of the configuration of an electronic control device 100A according to the second embodiment. The difference between the electronic control device 100A according to the second embodiment and the electronic control device 100 according to the first embodiment will be described below.

[0099] Figure 7 The electronic control device 100A shown in the figure is different from the electronic control device 100 ( 1st embodiment) in that the second power supply circuit 22 receives the power supply voltage VBAT supplied via the terminal VB as an input. Figure 1 ). As described above, the power supply voltage VBAT (first power supply voltage) is supplied to the terminal VB via the contact 12b of the power supply relay 12. Thus, similarly to the first power supply circuit 21, the power supply voltage VBAT supplied to the second power supply circuit 22 can be turned on / off by the contact 12b of the power supply relay 12. At the same time, the power supply voltage VBAT supplied to the second power supply circuit 22 is affected by the adhesion of the power supply relay 12 (contact 12b).

[0100] [Operation when the power relay is not stuck]

[0101] Next, the operation of the electronic control device 100A will be described. Figure 8 , the description will be given assuming that the power supply relay 12 can be normally controlled to be in the on or off state.

[0102] Figure 8 This is a timing chart showing an example of the operation when the power supply relay 12 is not on-stuck in the electronic control device 100A. Figure 8 Among the items recorded in the timing diagram of Figure 5 (First Embodiment) The items recorded in the timing diagram are assumed to be Figure 5 The state at the initial time t0 is Figure 8 The state is the same as the initial time t20.

[0103] Figure 8 At the time t21 shown, when the ignition switch 11 is switched from off to on, the relay drive circuit 13 is turned on, and the relay drive circuit 13 turns the power relay 12 into the on state. Since the power relay 12 is in the on state, the power supply voltage VBAT is supplied to the terminal VB, the first power supply circuit 21 outputs the internal voltage V1, and the second power supply circuit 22 outputs the internal voltage V2. The voltage detection circuit 30 and the register 31 receive the supply of the internal voltage V2 and start to operate. Furthermore, the voltage detection circuit 30 inputs the power supply voltage VBAT via the terminal VB, and when the power supply voltage VBAT exceeds the threshold voltage VBth, the output VBdet changes from the L level to the H level. The register 31 changes from the reset state to the non-reset state because the output VBdet of the voltage detection circuit 30 becomes the H level.

[0104] Next, at time t22, the microcomputer 102 reads the data stored in the register 31 via the communication circuit 40. The stored data in the register 31 at time t22 is at an L level, and the read data is also at an L level.

[0105] Next, at time t23 , the microcomputer 102 writes H-level data to the register 31 via the communication circuit 40 , and the H-level data is stored in the register 31 .

[0106] Then, at time t24, when the ignition switch 11 is switched from on to off, the relay drive circuit 13 is turned off. Therefore, the voltage of the terminal VB (first power supply voltage) gradually decreases due to the current consumption in the electronic control device 100. As the voltage of the terminal VB decreases, the internal voltage V2 can no longer maintain the voltage required for the voltage detection circuit 30 to operate and the register 31 to store data.

[0107] At time t25, the register 31 stops working, and the output of the register 31 is fixed (reset) to the L level. In addition, similarly to the above-mentioned time t5, when the voltage of the terminal VB drops below the threshold voltage VBth, the output VBdet of the voltage detection circuit 30 changes to the L level, the register 31 becomes reset, and the data stored in the register 31 changes to the L level.

[0108] After that, at time t26, the ignition switch 11 is turned on again, and the same operation as when the ignition switch 11 is turned on at time t21 is performed. At time t27, similarly to time t22, the microcomputer 102 reads L-level data from the register 31 via the communication circuit 40. Then, at time t28, the microcomputer 102 writes H-level data to the register 31 similarly to time t23.

[0109] [Operation when the power relay is stuck]

[0110] Next, a case where the power supply relay 12 cannot be normally controlled to the on or off state will be described.

[0111] Fig. 9 1 is a timing chart showing an example of the operation when the power supply relay 12 in the electronic control device 100A is stuck. Fig. 9 In the timing diagram shown in FIG. 1 , it is assumed that from the initial time t20 to the time t23 Figure 8 Similarly, the power relay 12 can be controlled to be turned on or off, but the power relay 12 is stuck in the on state from time t23 to time t30. Figure 8 The examples shown are the same, so the description is omitted.

[0112] After time t23 and until time t30, when the power relay 12 is stuck in the on state, when the ignition switch 11 is switched from on to off at time t30, the power relay 12 is stuck in the on state, so the power supply voltage VBAT continues to be supplied to the terminal VB of the electronic control device 100. At this time, the power supply voltage VBAT continues to be supplied to the first power supply circuit 21, but the voltage application through the terminal PSA is no longer performed because the ignition switch 11 is turned off, so the first power supply circuit 21 stops outputting the internal voltage V1. As a result, the communication circuit 40 and the microcomputer 102 stop operating because the supply of the internal voltage V1 stops.

[0113] On the other hand, the second power supply circuit 22 continues to output the internal voltage V2 by receiving the power supply voltage VBAT through the stuck power supply relay 12, so the voltage detection circuit 30 continues to operate and the output VBdet remains at the H level. Therefore, the register 31 retains the H level data written from the microcomputer 102 at time t23.

[0114] Thereafter, when the ignition switch 11 is turned on again at time t31, the power supply voltage VBAT is applied to the first power supply circuit 21 via the terminal PSA, the first power supply circuit 21 outputs the internal voltage V1, and the communication circuit 40 and the microcomputer 102 start operating.

[0115] At time t32, the microcomputer 102 reads the data stored in the register 31 via the communication circuit 40. Here, since the register 31 stores the H-level data, the microcomputer 102 reads the H-level data. That is, since it is assumed that the power relay 12 is stuck in the on state, the H-level data different from the L-level data read at time t22 is read. In this way, as in the first embodiment, by having the microcomputer 102 read the H-level data from the register 31, the microcomputer 102 can detect that the power relay 12 is stuck in the on state.

[0116] Then, at time t33, the microcomputer 102 writes H-level data to the register 31 in the same manner as at time t28.

[0117] When focusing on the difference between the electronic control device 100 in the first embodiment and the electronic control device 100A in the present embodiment, the second power supply circuit 22 is different from the first power supply circuit 21 in that it receives the supply of the power supply voltage VBAT via the terminal BATT, or receives the supply of the power supply voltage VBAT from the terminal VB via the power supply relay 12, which is the same as the first power supply circuit 21. In other words, it is shown that even when the second power supply circuit 22 is supplied with power through the same path as the first power supply circuit 21, the on-sticking of the power supply relay 12 can be detected.

[0118] As described above, in the electronic control device (electronic control device 100A) of the second embodiment, the monitoring unit (second power supply system module 120 ) operates using the first power supply voltage (power supply voltage VBAT via the terminal VB).

[0119] According to the electronic control device of the present embodiment of the above-mentioned structure, in the case of a structure in which the monitoring unit operates using the first power supply voltage (power supply voltage VBAT) supplied from the battery (battery 10) via the power supply relay (power supply relay 12), the monitoring unit is affected by the on / off (sticking) of the power supply relay 12. In the present embodiment thus constructed, also in the case where the power supply relay cannot be turned off and the power supply to the monitoring unit is normally cut off, sticking of the power supply relay can be detected based on the monitoring result of the first power supply voltage reflecting whether sticking of the power supply relay occurs, as in the first embodiment.

[0120] <3. Third embodiment>

[0121] In the third embodiment, an example of the structure and operation of an electronic control device for detecting that the power relay 12 is stuck, and then preventing the erroneous detection of the power relay 12 being stuck when the ignition switch 11 is turned on again before the voltage at the terminal VB drops below the threshold voltage VBth even though the power relay 12 is not actually stuck because the ignition shut-off period is short.

[0122] Fig.10 1 is a block diagram showing an example of the configuration of an electronic control device 100B according to the third embodiment. The difference between the electronic control device 100B according to the third embodiment and the electronic control device 100 according to the first embodiment will be described below.

[0123] Fig.10 The electronic control device 100B shown in the figure further includes a timer circuit 32 for measuring the off time from the moment when the ignition switch 11 is switched from the on state to the off state in the second power supply system module 120B operated by supplying the internal voltage V2. That is, the third embodiment is a structure in which the timer circuit 32 is provided in addition to the structure of the first embodiment.

[0124] The timer circuit 32 is connected to the communication circuit 40 and the wiring PSA, and measures time when the power supply voltage VBAT is not supplied to the wiring PSA. The microcomputer 102 can read the time information measured by the timer circuit 32 from the timer circuit 32 via the communication circuit 40 .

[0125] Fig.11 3 is a block diagram showing an example of the configuration of the timer circuit 32 .

[0126] The timer circuit 32 is, for example, Fig.11As shown, the counter 321 is composed of a counter 321 that periodically increases and outputs a count value CNT according to a clock signal not explicitly shown, a count threshold CNTth, and a count comparison circuit 322 that compares the count value CNT with the count threshold CNTth. The count comparison circuit 322 outputs a count comparison result CNTdet to the communication circuit 40 as binary information of an H level or an L level.

[0127] The counter 321 fixes the count value CNT to zero when the potential of the PSA terminal is the power supply voltage VBAT, and periodically increases the count value CNT according to a clock signal (not shown) when the potential of the PSA terminal is the ground potential.

[0128] Fig.12 2 is a block diagram showing an example of the configuration of the count comparison circuit 322 included in the timer circuit 32 .

[0129] The count comparison circuit 322 includes a comparator 322a that compares the count value CNT of the counter 321 with the count threshold CNTth and outputs the comparison result, and a register 322b that stores the comparison result output by the comparator 322a. The comparator 322a outputs H-level data as the count comparison result CNTdet when the count value CNT is greater than the count threshold CNTth, and outputs L-level data as the count comparison result CNTdet in other cases. For example, the comparator 322a can be configured by a comparator.

[0130] The microcomputer 102 can read the count comparison result CNTdet from the register 322b of the timer circuit 32 via the communication circuit 40 and can write a required value to the count threshold CNTth. For example, the count threshold CNTth is stored in a register or memory included in the timer circuit 32.

[0131] The electronic control device 100B can detect the sticking of the power relay and avoid erroneous detection when the ignition off period is short. Figure 13 to Figure 15 The timing diagram shown is used for explanation.

[0132] [Operation when the power relay is not stuck (1)]

[0133] Fig.13 This is a timing chart showing an example of the operation when the power supply relay 12 is not on-stuck in the electronic control device 100B.

[0134] First, in Fig.13The timing diagram shown is described assuming that the power relay can be normally controlled to be on or off and the off period of the ignition switch 11 is sufficiently long. Specifically, consider that after the ignition switch 11 is turned off, the voltage at the terminal VB drops below the threshold voltage VBth, and then the ignition switch 11 is turned on again.

[0135] Fig.13 Among the items recorded in the timing diagram of Figure 5 (First Embodiment) The items recorded in the timing diagram are assumed to be Figure 5 The state at the initial time t0 is Fig.13 The state at the initial time t40 is the same as that at the initial time t40. In addition, regarding the common items, the actions from the initial time t40 to the time t44 are basically the same. Fig.13 and Figure 5 For the sake of simplicity, it is assumed that the count value CNT of the counter 321 is zero at the initial time t20 and the count comparison result CNTdet is at the L level of the initial state.

[0136] Consider Fig.13 At time t41 shown in FIG. 1 , the ignition switch 11 is switched from OFF to ON. The operation of the electronic control device 100B at this time is similar to that of the first embodiment ( Figure 5 ) is the same as the action at time t1 described in . That is, the power supply voltage VBAT is supplied to the terminal PSA via the ignition switch 11, and the relay drive circuit 13 turns on the power supply relay 12. Since the power supply relay 12 is turned on, the power supply voltage VBAT is supplied to the terminal VB, and the first power supply circuit 21 outputs the internal voltage V1. The communication circuit 40 and the microcomputer 102 receive the supply of the internal voltage V1 and start to operate.

[0137] The power supply voltage VBAT is similarly supplied to the voltage detection circuit 30. When the power supply voltage VBAT exceeds the threshold voltage VBth, the output VBdet changes from the L level to the H level. The register 31 changes from the reset state to the non-reset state when the output VBdet becomes the H level.

[0138] Next, at time t42, the microcomputer 102 reads the data stored in the register 31 and the count comparison result CNTdet stored in the register 322b of the timer circuit 32 via the communication circuit 40. Specifically, in the present embodiment, at the initial time t40, the data stored in the register 31 is set to the L level, and the count comparison result CNTdet is also set to the L level of the initial state. Therefore, regarding the data read by the microcomputer 102 at time t42, both the data stored in the register 31 and the count comparison result CNTdet are at the L level.

[0139] Next, at time t43 , the microcomputer 102 writes H-level data to the register 31 via the communication circuit 40 , and the H-level data is stored in the register 31 .

[0140] Next, at time t44, when the ignition switch 11 is switched from on to off, the relay drive circuit 13 is turned off. Therefore, the voltage of the terminal VB (first power supply voltage) gradually decreases due to the current consumption in the electronic control device 100B. However, Fig.13 The voltage at the terminal VB decreases faster than Figure 5 The voltage at the terminal VB shown decreases more slowly.

[0141] In addition, at time t44, the timer circuit 32 (counter 321) starts measuring the off time of the ignition switch 11, and initializes the count comparison result CNTdet to the L level. In addition, in this embodiment, the initial state of the count comparison result CNTdet is recorded as the L level, so the value of the count comparison result CNTdet does not change before and after the writing at time t43.

[0142] At time t45, when the voltage of the terminal VB drops below the threshold voltage VBth, the output VBdet of the voltage detection circuit 30 changes to the L level. Therefore, the register 31 is reset, and the data stored in the register 31 changes to the L level.

[0143] At time t46, when the count value CNT of the counter 321 of the timer circuit 32 reaches the count threshold value CNTth, the output of the count comparison result CNTdet of the count comparison circuit 322 changes to the H level.

[0144] Thereafter, when the ignition switch 11 is turned on again at time t47, the same operation as when the ignition switch 11 is turned on at time t41 is performed, and the count value CNT of the timer circuit 32 is also restored to zero. On the other hand, the count comparison result CNTdet of the timer circuit 32 is not changed and its value is retained.

[0145] At time t48, similarly to time t42, the microcomputer 102 reads the data stored in the register 31 and the count comparison result CNTdet output by the timer circuit 32 via the communication circuit 40. The difference between time t42 and time t48 is that at time t46, the count value CNT of the timer circuit 32 reaches the count threshold value CNTth, so the H level is read to the microcomputer 102 as the count comparison result CNTdet data.

[0146] Finally, at time t49, similarly to time t43, the microcomputer 102 writes H-level data to the register 31. Based on the above, Fig.13In the timing chart of , since the read data of the register 31 after the ignition switch 11 is turned on again is L level, it can be determined that the power supply relay 12 is normally turned off.

[0147] [Operation when the power relay is not stuck (2)]

[0148] Fig.14 The operation of the electronic control device 100B when the power supply relay 12 is not stuck is shown. Fig.13 Timing diagrams for different examples.

[0149] Then, in Fig.14 In the timing diagram shown, the power relay 12 is normally controlled to be on or off and the off period of the ignition switch 11 is short. Specifically, consider the case where the ignition switch 11 is turned on again before the voltage of the terminal VB drops below the threshold voltage VBth after the ignition switch 11 is turned off. At this time, it is assumed that the count value CNT of the timer circuit 32 that counts the off period of the ignition switch 11 is before reaching the count threshold value CNTth. In addition, Fig.14 The action from the initial time t40 to the time t44 in Fig.13 The examples shown are the same, so the description is omitted.

[0150] Consider the case where the ignition switch 11 is turned off at time t44 and then turned on again at time t50. Fig.13 The difference between the time t47 and the time t50 is that the voltage of the terminal VB has not fallen below the threshold voltage VBth (the dotted portion of the dashed line) at the time t50, and the output VBdet of the voltage detection circuit 30 is at the H level. In addition, as described above, the count value CNT of the timer circuit 32 at the time t50 is before reaching the count threshold value CNTth, and the value of the count comparison result CNTdet is at the L level.

[0151] At time t51, the microcomputer 102 reads the data stored in the register 31 and the count comparison result CNTdet output by the timer circuit 32 via the communication circuit 40. Then, at time t52, the microcomputer 102 writes H level data to the register 31 in the same manner as at time t43.

[0152] Time t51 and Fig.13 The difference between the time t48 and the time t48 is that although the power supply relay 12 does not have a closed state, the H level data is read from the register 31. That is, in the first embodiment, the power supply relay 12 is judged to be in the closed state based on the fact that the data read from the register 31 is at an H level. However, Fig.14The timing chart of indicates that there is a possibility that the power source relay 12 is misdiagnosed as being stuck in the on state, depending on the time from when the ignition switch 11 is turned off to when it is turned on again.

[0153] In order to avoid the above-mentioned misdiagnosis, in this embodiment, by configuring the timer circuit 32, the off period of the ignition switch 11 is measured, and when the ignition switch 11 is turned on again before the voltage of the terminal VB drops below the threshold voltage VBth of the voltage detection circuit 30, it is possible to prevent the misdiagnosis that the power supply relay 12 is in the on-stick state. Specifically, when the microcomputer 102 reads the L level in the count comparison result CNTdet of the timer circuit 32, the microcomputer 102 ignores the H level data read from the register 31, and determines that the power supply relay 12 is not in the on-stick state.

[0154] [Operation when the power relay is stuck]

[0155] Next, a case where the power supply relay 12 cannot be normally controlled to the on or off state will be described.

[0156] Fig.15 1 is a timing chart showing an example of operation when the power supply relay 12 in the electronic control device 100B is stuck. Fig.15 In the timing diagram shown in FIG. 1 , it is assumed that from the initial time t40 to the time t43 Fig.13 Similarly, the power relay 12 can be controlled to be turned on or off, but the power relay 12 is stuck in the on state from time t43 to time t53. Fig.13 The examples shown are the same, so the description is omitted.

[0157] After the power relay 12 is stuck in the on state during the period from time t43 to time t53, when the ignition switch 11 is switched from on to off at time t53, the operation of the electronic control device 100B is similar to that of the first embodiment ( Figure 6 The operation at time t53 of this embodiment is the same as that at time t10 described in Figure 6 The difference in the operation at time t10 shown is that the timer circuit 32 starts measuring the OFF time of the ignition switch 11 and initializes the count comparison result CNTdet to the L level. Fig.13 Similarly to the description at time t44 shown, in this embodiment, the initial state of the count comparison result CNTdet is described as L level, so the value of the count comparison result CNTdet does not change before and after the writing at time t43.

[0158] At time t54, when the count value CNT of the counter 321 of the timer circuit 32 reaches the count threshold value CNTth, the count comparison result CNTdet of the count comparison circuit 322 changes to the H level.

[0159] Thereafter, when the ignition switch 11 is turned on again at time t55, the power supply voltage VBAT is applied via the terminal PSA to the first power supply circuit 21. Then, the first power supply circuit 21 outputs the internal voltage V1, and the communication circuit 40 and the microcomputer 102 start to operate.

[0160] At time t56, the microcomputer 102 reads the data stored in the register 31 and the count comparison result CNTdet output by the timer circuit 32 via the communication circuit 40. At time t54, the data stored in the register 31 and the count comparison result CNTdet are at H level, and the microcomputer 102 reads H level data for both the data stored in the register 31 and the count comparison result CNTdet. Then, at time t57, the microcomputer 102 writes H level data to the register 31 in the same manner as at time t43.

[0161] Here, regarding the operation of the electronic control device 100B, consider Fig.14 and Fig.15 The differences in the timing diagrams shown. Fig.15 In the OFF period of the ignition switch 11, the count value CNT of the timer circuit 32 exceeds the count threshold value CNTth, and the count comparison result CNTdet is H level. Fig.14 different.

[0162] The count threshold CNTth can be written as a required value from the microcomputer 102 via the communication circuit 40. Fig.13 As shown, after the voltage of the terminal VB drops below the threshold voltage VBth of the voltage detection circuit 30 after the ignition switch 11 is turned off, the count output CNT of the timer circuit 32 exceeds the count threshold CNTth. Thus, the present embodiment can be used as a means for preventing misdiagnosis of the on-stuck power supply relay 12.

[0163] That is, when the microcomputer 102 appropriately sets the counting threshold CNTth and turns on the ignition switch 11, the microcomputer 102 reads the stored data and the counting comparison result CNTdet of the register 31 via the communication circuit 40, and can determine that the power relay 12 is stuck only when the read data are all at H level.

[0164] According to the above description, it is known that the structure and operation of the electronic control device 100B can prevent the power relay 12 from being erroneously detected as being stuck, when the ignition switch 11 is turned on again before the voltage at the terminal VB drops below the threshold voltage VBth, even though the relay 12 is not actually stuck, because the ignition shut-off period is short.

[0165] As described above, in the electronic control device (electronic control device 100B) of the third embodiment, the processor (processor 102a) further includes a timer circuit (timer circuit 32) that measures the time when the power supply (ignition switch 11) is turned off. Then, the processor (processor 102a) performs control not to detect the sticking abnormality of the power supply relay (power supply relay 12) when the measured time (count value CNT) of the timer circuit is less than a threshold value (count threshold value CNTth) set based on the time required from the power supply being turned off until the first power supply voltage (power supply voltage VBAT via terminal VB) drops below the threshold voltage (VBth).

[0166] According to the electronic control device of the above structure, when the power off time (measured time) is below a threshold value set based on the time required from power off until the first power supply voltage drops below the threshold voltage, the sticking abnormality of the power supply relay is not detected. In this way, when the first power supply voltage does not drop to the threshold voltage because the power off time is short, the sticking abnormality detection is not performed, thereby preventing the false detection of the sticking abnormality of the power supply relay.

[0167] In addition, in the electronic control unit (electronic control unit 100B) of the present embodiment, the processor (processor 102a) detects a sticking abnormality of the power relay (power relay 12) based on information read from the storage unit (register 31) when the measured time of the timer circuit (timer circuit 32) exceeds a threshold value (counting threshold value CNTth) set based on the time required from when the power supply (ignition switch 11) is turned off until the first power supply voltage (power supply voltage VBAT via terminal VB) drops below the threshold voltage (VBth).

[0168] According to the electronic control device of the above configuration, after reliably confirming that the first power supply voltage has dropped to the threshold voltage, the sticking abnormality of the power supply relay is detected based on the information read from the storage unit, thereby preventing erroneous detection of the sticking abnormality of the power supply relay.

[0169] [Modification of the Third Embodiment]

[0170] In the third embodiment, the count value CNT corresponding to the OFF period of the ignition switch 11 is initialized by turning on the ignition switch 11. As a modification of the third embodiment, an example of initializing the count value CNT by another method will be described.

[0171] Fig.16 This is a timing chart showing another example of the operation when the power supply relay is stuck in the electronic control device according to the modification of the third embodiment. Fig.16 In the timing diagram shown in FIG. 1 , the actions from the initial time t40 to the time t43 and from the time t53 to the time t54 are similar to those in FIG. Fig.13 The examples shown are the same, so the description is omitted.

[0172] When the ignition switch 11 is turned on again at time t60, the power supply voltage VBAT is applied to the first power supply circuit 21 via the terminal PSA. Then, the first power supply circuit 21 outputs the internal voltage V1, and the communication circuit 40 and the microcomputer 102 start to operate.

[0173] Figure 13 to Figure 15 In the example, the count value CNT of the timer circuit 32 is restored to zero by turning on the ignition switch 11, but Fig.16 In the example of , the count value CNT is not reset. When the ignition switch 11 is turned on, the count value CNT of the counter 321 at that time is stored.

[0174] At time t61, the microcomputer 102 reads the data stored in the register 31 via the communication circuit 40. Then, the microcomputer 102 determines whether the power supply relay 12 is stuck based on the read data of the register 31 and the count comparison result CNTdet. Then, at time t62, the microcomputer 102 writes H level data to the register 31 in the same manner as at time t43.

[0175] Then, when the ignition switch 11 is turned off again at time t63, other circuits in the second power system module 120B or the microcomputer 102 outputs a reset pulse to the timer circuit 32. The timer circuit 32 receives the reset pulse and returns the count value CNT to zero, and then increases the count value CNT according to the off period of the ignition switch 11.

[0176] <4. Others>

[0177] The present invention is not limited to the first to third embodiments described above, and various other application examples and modified examples can be adopted without departing from the gist of the present invention described in the scope of claims.

[0178] For example, the first to third embodiments described above describe the structure of the electronic control device in detail and specifically to assist understanding of the present invention, but are not limited to having all the described components. In addition, other components may be added, replaced, or deleted for a part of the structure of each embodiment.

[0179] For example, in the third embodiment, in order to determine the off period of the ignition switch, a configuration is adopted in which the microcomputer 102 can write the count threshold value CNTth via the communication circuit 40, and a configuration is adopted in which only the count comparison result CNTdet is read from the timer circuit 32. However, a configuration may be adopted in which the microcomputer 102 reads the count value CNT outputted by the counter 321 of the timer circuit 32 via the communication circuit 40, and compares it with a threshold value set inside the microcomputer 102 to determine the off period.

[0180] In addition, in the first to third embodiments, as an example of the structure of the voltage detection circuit 30, a structure is adopted in which the VB wiring is connected to the non-inverting input terminal of the comparator 301, and the threshold voltage VBth is input to the inverting input terminal to compare the voltages. However, as long as the structure can obtain the same effect, it can be implemented with other circuits.

[0181] Furthermore, each component described in the electronic control device 100 may be an integrated circuit in which all components are formed in the same semiconductor chip, or each component may be divided into a plurality of components.

[0182] For example, the first power supply circuit 21 , the second power supply circuit 22 , the relay drive circuit 13 , and the communication circuit 40 described as components of the power supply ICs 101 and 101B may be mounted in the electronic control device 100 as independent components.

[0183] In addition, for each of the above structures, functions, processing units, etc., part or all of them can be implemented by hardware, for example, by designing in an integrated circuit. As hardware, FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit) can be used. In addition, each of the above components, functions, etc. can also be implemented by software. In the case of execution by software, for example, a processor 102a such as a CPU provided in the electronic control device can read a computer program stored in a recording medium (memory 102b) such as a ROM provided inside the electronic control device and execute it sequentially.

[0184] In the above-mentioned embodiment, the control lines and information lines are shown as necessary for explanation, and not all the control lines and information lines on the product are necessarily shown. In fact, it can be considered that almost all the components are connected to each other.

[0185] Description of Reference Numerals

[0186] 10…battery, 11…ignition switch, 12…power relay, 12a…coil, 12b…contact, 13…relay drive circuit, 131…switching element, 21…first power circuit, 22…second power circuit, 30…voltage detection circuit, 301…comparator, 31…register, 311…D flip-flop, 32…timer circuit, 321…counter, 322…count comparison circuit, 322a…comparator, 322b…register, 40…communication circuit, 100, 100A, 100B…electronic control device, 101, 101B…power IC, 102…microcomputer, 110…first power system module, 120, 120B…second power system module, CNT…count value, CNTdet…count comparison result, CNTth…count threshold, V1…first internal voltage, V2…second internal voltage, VBdet…voltage detection result, VBth…threshold voltage.

Claims

1. An electronic control device, characterized in that: include: A relay driving circuit, which is used to control the power relay to be turned on or off according to the information of the power supply being turned on or off; an electronic circuit that operates using a first power supply voltage supplied from a battery via the power supply relay; and a monitoring unit that monitors the first power supply voltage when the power supply is turned off, which can reflect whether the sticking of the power supply relay occurs, and stores the monitoring result, The monitoring unit includes: a voltage detection circuit, which compares the first power supply voltage with a threshold voltage, outputs a high level signal when the first power supply voltage is greater than the threshold voltage, and outputs a low level signal otherwise; and a storage unit that stores, as the monitoring result, information indicating whether the first power supply voltage has decreased based on a signal output by the voltage detection circuit when the power supply is turned off, The electronic circuit includes a processor that reads information indicating whether the first power supply voltage has decreased stored in the storage unit and writes the information to the storage unit. The processor performs determination processing and writing processing, In the judgment process, the storage unit is read when the power is switched from off to on, and when the first read information read from the storage unit last time is information indicating a low level and the second read information read from the storage unit this time is information indicating a high level, it is judged that a sticking abnormality has occurred in the power relay, In the write process, information is read from the storage unit when the power source is turned on from off, and after the information is read from the storage unit, information indicating a high level is written to the storage unit.

2. The electronic control device according to claim 1, characterized in that: The storage unit is configured to store and output information written by the processor, and to reset the stored information using a signal obtained by inverting a low-level signal output by the voltage detection circuit, thereby outputting a low-level signal.

3. The electronic control device according to claim 1, characterized in that: The monitoring unit operates using a second power supply voltage supplied from the battery via a path not passing through the power supply relay.

4. The electronic control device according to claim 1, characterized in that: The monitoring unit operates using the first power supply voltage.

5. The electronic control device according to claim 3, characterized in that: The monitoring unit further includes a timer circuit for measuring the time from when the power supply is turned off. The processor controls so that the sticking abnormality of the power relay is not detected when the measured time of the timer circuit is below a threshold value, and the threshold value is set based on the time required from the power supply being turned off to the first power supply voltage falling below a threshold voltage.

6. The electronic control device according to claim 5, characterized in that: The processor detects adhesion abnormality of the power relay based on information read from the storage unit when the measured time of the timer circuit exceeds a threshold value, and the threshold value is set based on the time required from when the power is turned off to when the first power supply voltage drops below a threshold voltage.

Images