electronic control device

Abstract

The present application provides an electronic control device mounted on an electric vehicle, which can reliably cut off a high-voltage power line when the vehicle collides or when a power supply circuit fails, and which is excellent in reliability and convenience. The electronic control device is characterized by comprising: an external load switching element that drives an external load; a control device that drives the external load switching element; a cutting transistor that cuts off a connection between an internal GND and an external GND or a connection between an internal power supply system and an external power supply system; a diagnosis circuit that inputs a diagnosis signal of a control circuit that controls the external load through the external load switching element and a diagnosis signal of the control device and outputs a diagnosis result; and an output holding circuit that holds an output signal of the diagnosis circuit, and the electronic control device cuts off the connection between the internal GND and the external GND or the connection between the internal power supply system and the external power supply system through the cutting transistor according to a signal held by the output holding circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to a configuration of an in-vehicle electronic control device, and particularly relates to an effective technology for an electronic control device mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle. BACKGROUND

[0002] In recent years, automobiles are being electrified due to exhaust gas regulations, and the number of sales of hybrid vehicles (HEV: Hybrid Electric Vehicle) or electric vehicles (EV: Electric Vehicle) is increasing.

[0003] For example, in an HEV vehicle, a high voltage power supply of about 400 V is supplied from a lithium ion battery to an inverter in order to operate a motor. In the case where the high voltage power supply line contacts a vehicle body at the time of a collision or the like, there is a possibility that a person contacting the vehicle is electrocuted due to the contact with the vehicle.

[0004] In order to prevent such electrocution, in an HEV vehicle, a relay is used between a lithium ion battery and a load, and control to cut the high voltage power supply line is performed except at the time of vehicle operation.

[0005] As background art in this technical field, there is, for example, the technology of Patent Literature 1. In Patent Literature 1, there is disclosed "a power supply cut-off device having: a power supply circuit mounted on a vehicle, having a battery, a load, and a relay; a relay control section that performs contact separation of the battery and the load by controlling the relay; and a rupture mechanism that ruptures a signal line provided between the relay control section and the relay at the time of a vehicle collision, thereby separating the battery and the load".

[0006] Prior Art Documents

[0007] Patent Literature

[0008] Patent Literature 1: Japanese Patent Application Laid-Open No. 2004-159439 SUMMARY

[0009] Problems to be Solved by the Invention

[0010] As described above, in an HEV vehicle, a relay is used between a lithium ion battery and a load, but there is a possibility that an on-failure in which the relay is fixed in an on state and cannot be turned off occurs due to a short circuit or the like between an output circuit of the relay and a peripheral circuit, caused by a failure of a circuit component that controls the relay, or destruction of a unit caused by a collision of a vehicle or the like.

[0011] If the high voltage power supply line contacts a vehicle body or the like in a state where the relay is in an on-failure, there is a problem that a person contacting the vehicle is electrocuted without noticing the failure.

[0012] In view of such a problem, the patent document 1 discloses a technique of forcibly cutting off a relay by cutting a high-voltage power supply line with a cutting blade in the event of a vehicle collision.

[0013] According to the patent document 1, the high-voltage power supply line can be reliably cut off at the time of a vehicle collision, but the cutting off of the wire harness is performed even when a turn-on failure of the relay does not occur, so that the wire harness or the like needs to be replaced even by a false operation or a slight collision. In addition, a turn-on failure of the relay caused by a failure of a circuit cannot be prevented.

[0014] Therefore, an object of the present application is to provide an electronic control device in which a high-voltage power supply line can be reliably cut off at the time of a vehicle collision or a failure of a power cut-off circuit, and which is easy to recover, and which is excellent in reliability and convenience, in an electronic control device mounted on an electric vehicle.

[0015] Technical means for solving the problem

[0016] To solve the above problem, the present application is characterized by comprising: an external load switching element that drives an external load; a control device that drives the external load switching element; a cutting transistor that cuts off a connection between an internal GND and an external GND or a connection between an internal power supply system and an external power supply system; a diagnosis circuit that inputs a diagnosis signal of a control circuit that controls the external load by the external load switching element and a diagnosis signal of the control device, and outputs a diagnosis result; and an output holding circuit that holds an output signal of the diagnosis circuit, and the electronic control device cuts off the connection between the internal GND and the external GND or the connection between the internal power supply system and the external power supply system by the cutting transistor in accordance with a signal held by the output holding circuit.

[0017] Effects of the invention

[0018] According to the present application, an electronic control device in which a high-voltage power supply line can be reliably cut off at the time of a vehicle collision or a failure of a power cut-off circuit, and which is easy to recover, and which is excellent in reliability and convenience, can be realized in an electronic control device mounted on an electric vehicle.

[0019] The above problems, configurations, and effects other than the above are made clear by the following description of the embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic configuration diagram of an electronic control device of Embodiment 1 of the present application.

[0021] Figure 2 is a timing chart showing the operation of the electronic control device of Figure 1

[0022] Figure 3 ​This is a schematic diagram of the electronic control device according to Embodiment 2 of the present invention.

[0023] Figure 4 This is a schematic diagram of the electronic control device according to Embodiment 3 of the present invention.

[0024] Figure 5 This is a schematic diagram of the electronic control device according to Embodiment 4 of the present invention.

[0025] Figure 6 This is a schematic diagram of the electronic control device according to Embodiment 5 of the present invention.

[0026] Figure 7 This is a schematic diagram of the electronic control device according to Embodiment 6 of the present invention.

[0027] Figure 8 This is a schematic diagram of the electronic control device according to Embodiment 7 of the present invention. Detailed Implementation

[0028] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. Furthermore, in the drawings, the same reference numerals are used for the same components, and detailed descriptions of repeated parts are omitted.

[0029] Example 1

[0030] Reference Figure 1 and Figure 2 The electronic control device of Embodiment 1 of the present invention will be described. Figure 1 This is a schematic diagram of the electronic control device in this embodiment. Figure 1 As shown, the electronic control unit (ECU) 100 of this embodiment includes an external load switching element 103 for driving an external load 101 and a control device 102 such as a microcontroller for driving the external load switching element 103.

[0031] The control device diagnostic signal 114 from the control device 102, which is HI under normal conditions, is filtered by a filter capacitor 104, a filter resistor 105, and other filters before being input to the NOR circuit 106. Additionally, the output control circuit diagnostic signal 115, which is LO when the external load 101 is turned on, is input to the NOR circuit 106.

[0032] In addition, the electronic control unit (ECU) 100 includes an output holding circuit 107 that holds the output from the NOR circuit 106, and a charge extraction transistor 108 that extracts the gate charge of the cut-off transistor 109. The cut-off transistor 109 has the function of cutting off the external GND (vehicle GND) 111 of the vehicle and the like and the internal GND (ECU GND) 112 of the ECU.

[0033] The GND within the electronic control device (ECU) 100 can control the influence at the time of GND disconnection depending on which of the vehicle GND 111 and the ECU GND 112 is set as the GND, but in order to maintain the disconnection state after disconnection, the GND of the output holding circuit 107 and the GND of the charge extraction transistor 108 are set to be shared with the external GND (vehicle GND) 111.

[0034] Use Figure 2 The operation of the electronic control device (ECU) 100 of the present embodiment is described.

[0035] The control device diagnosis signal 114 is LO output until the controller 102 such as a microcontroller is activated. On the other hand, the output control circuit diagnosis signal 115 is pulled up by the battery voltage VBAT 110, and thus maintains HI output. At this time, the NOR circuit 106 is LO output, and the output holding circuit 107 is also LO output, and thus the charge extraction transistor 108 becomes the off state.

[0036] Since the disconnection transistor 109 is turned on by the battery voltage VBAT 110, the ECU internal GND 112 is connected to the external GND 111 of the vehicle or the like.

[0037] After the activation of the control device 102, if the control device 102 is normal, the control device diagnosis signal 114 is made to output HI. Since the NOR circuit 106 maintains LO output, the disconnection transistor 109 maintains being turned on, and the ECU internal GND 112 maintains connection to the external GND 111 of the vehicle or the like.

[0038] The external load 101 is turned on by the control device (microcontroller) 102, and the output control circuit signal 115 is made to output LO. The controller diagnosis signal 114 is HI, the NOR circuit 106 maintains LO output, and thus the disconnection transistor 109 maintains being turned on, and the ECU internal GND 112 maintains connection to the external GND 111 of the vehicle or the like.

[0039] Even in the case where the control device diagnosis signal 114 becomes LO due to a failure of the internal circuit of the electronic control device (ECU) 100 or an external signal (collision signal) 113 or the like from the outside, in the case where the output control circuit diagnosis signal 115 is HI and the external load 101 is off, the NOR circuit 106 maintains LO output, and thus the disconnection transistor 109 maintains being turned on, and the ECU internal GND 112 maintains connection to the external GND 111 of the vehicle or the like.

[0040] When the control device diagnosis signal 114 is LO due to a failure of an internal circuit of the electronic control unit (ECU) 100 or an external signal (conflict signal) 113 from the outside, and the like, in the case where the external load 101 is in an on-failure state, the output control circuit diagnosis signal 115 becomes LO, so the NOR circuit 106 becomes HI. The charge extraction transistor 108 receives the HI output of the output holding circuit 107 and turns on, and extracts the gate voltage of the cutoff transistor 109. Since the cutoff transistor 109 is turned off, the connection between the ECU internal GND 112 and the external GND 111 of the vehicle or the like is cut off.

[0041] Since the ECU internal GND 112 and the external GND 111 of the vehicle or the like are disconnected, the path through which the external load 101 flows current to the external GND 111 of the vehicle or the like through the external load switching element 103 is cut off, so the external load 101 is cut off.

[0042] In addition, the control device diagnosis signal 114 is not only used for the purpose of preventing a failure of the internal circuit or the like, but can also be used for the purpose of receiving a signal from an ECU different from the electronic control unit (ECU) 100, setting the control device diagnosis signal 114 to LO output, and thereby preventing an on-failure of the external load 101.

[0043] The cutoff transistor 109 that performs the disconnection of the ECU internal GND 112 and the external GND 111 of the vehicle or the like is held in cutoff by the output holding circuit 107, so the battery voltage VBAT 110 supplied to the electronic control unit (ECU) 100 is temporarily disconnected and then connected again, and thus the holding of the output holding circuit 107 is released, and therefore the external load 101 can be connected again.

[0044] As described above, the electronic control unit (ECU) 100 of the present embodiment includes: an external load switching element 103 that drives an external load 101; a control device 102 that drives the external load switching element 103; a cutoff transistor 109 that cuts off the connection between an ECU internal GND 112 and an external GND 111 of a vehicle or the like; a diagnosis circuit (NOR circuit 106) that takes as inputs a diagnosis signal of a control circuit that controls the external load 101 through the external load switching element 103 (output control circuit diagnosis signal 115) and a diagnosis signal of the control device 102 (control device diagnosis signal 114), and outputs a diagnosis result; and an output holding circuit 107 that holds the output signal of the diagnosis circuit (NOR circuit 106), and the electronic control unit cuts off the connection between the ECU internal GND 112 and the external GND 111 of the vehicle or the like by the cutoff transistor 109 in accordance with the signal held by the output holding circuit 107.

[0045] In addition, an on-failure of the external load 101 is detected based on a diagnosis signal (output control circuit diagnosis signal 115) of the control circuit that controls the external load 101 through the external load switch element 103 and a diagnosis signal (control device diagnosis signal 114) of the control device 102.

[0046] Thus, when the external load 101 is in an on-failure at the time of a circuit failure or a vehicle collision, the external load 101 can be reliably disconnected.

[0047] In addition, when the external load 101 is a relay that controls a high-voltage power supply line, by reliably cutting off, even in the case where the high-voltage power supply line is in contact with the vehicle body, electric shock can be prevented.

[0048] Embodiment 2

[0049] Reference Figure 3 An electronic control device of Embodiment 2 of the present application is described. Figure 3 is a schematic configuration diagram of the electronic control device of the present embodiment. As Figure 3 indicated, the electronic control device (ECU) 100 of the present embodiment, in relation to Embodiment 1 Figure 1 ), in order to control the device diagnosis signal 114, a filter circuit 120 is added, which uses a filter capacitor 104, 118, a filter resistor 105, 117, and a filter diode 116, and the like. The other configurations are the same as Embodiment 1 Figure 1 ).

[0050] The purpose of the filter circuit 120 is to remove the direct current component by the filter capacitor 118. In the case where the PWM output is input as the input of the filter circuit 120, at the time of HI input of the PWM, the charge is accumulated in the filter capacitor 104 by the filter capacitor 118 and the other circuit dividing. At the time of LO input, the charge of the filter capacitor 118 is discharged by the filter resistor 117. Since the charge of the filter capacitor 104 is limited by the filter diode 116, the charge is not discharged from the filter resistor 117. By the repetition of HI and LO, the filter output becomes HI output.

[0051] The control device output signal 119 is PWM output in the normal state. The controller diagnosis signal 114 becomes HI by the filter circuit 120.

[0052] In the case where the controller output signal 119 is fixed to LO output or HI output, the controller diagnosis signal 114 is made to be LO by the filter circuit 120.

[0053] Even in the case where the control device output signal 119 is fixed to HI output due to a collision of the vehicle or the like, if the configuration of the present embodiment, since the control device diagnosis signal 114 becomes LO, in the case where the external load 101 is an on-fault, it is possible to cut off.

[0054] As described above, the electronic control device (ECU) 100 of the present embodiment is provided with the filter circuit 120 constituted by the filter capacitor 104, 118, the filter resistor 105, 117, and the filter diode 116, and the filter circuit 120 is connected between the control device 102 and the diagnosis circuit (NOR circuit 106). Then, the PWM output from the control device 102 is made to pass through the filter circuit 120, thereby removing the direct current component output from the control device 102, and inputting to the diagnosis circuit (NOR circuit 106) as the diagnosis signal of the control device 102 (control device diagnosis signal 114).

[0055] Further, by adjusting the time constant of the filter circuit 120 based on the filter capacitors 104, 118 and the filter resistors 105 and 117, the time from the stop of the PWM output from the control device 102 to the disconnection of the connection between the ECU internal GND 112 and the external GND 111 of the vehicle or the like is controlled.

[0056] By changing the resistance value of the resistor and the capacitance value of the capacitor constituting the filter circuit 120, it is possible to change the timing at which the control device diagnosis signal 114 becomes HI, LO, and thus it is possible to adjust the timing at which the ECU internal GND 112 and the external GND 111 of the vehicle or the like are cut off.

[0057] Embodiment 3

[0058] Reference Figure 4 An electronic control device of Embodiment 3 of the present application is described. Figure 4 is a schematic configuration diagram of the electronic control device of the present embodiment. As Figure 4 shown, the electronic control device (ECU) 100 of the present embodiment is provided with the filter circuit 120 constituted by the filter capacitor 104, 118, the filter resistor 105, 117, and the filter diode 116, and the filter circuit 120 is connected between the control device 102 and the external load switch element 103. Figure 1 ), a filter circuit 120 is added between the control device 102 such as a microcontroller and the external load switch element 103. The other configurations are the same as in Embodiment 1 Figure 1 ).

[0059] As shown in Figure 4 , the electronic control device (ECU) 100 of the present embodiment is provided with the filter circuit 120 constituted by the filter capacitor 104, 118, the filter resistor 105, 117, and the filter diode 116, and the filter circuit 120 is connected between the control device 102 and the external load switch element 103.

[0060] By outputting PWM from the control device 102, the gate voltage of the external load switching element 103 becomes HI, the external load switching element 103 is turned on, and the external load 101 is turned on.

[0061] Even if the control device output signal 119 is fixed at HI output due to a fault in the internal circuit of the electronic control unit (ECU) 100, the external load switching element 103 will not be turned on, thus preventing the external load 101 from failing to turn on.

[0062] In addition, when the control device 102 does not control the external load switching element 103, the control device diagnostic signal 114 becomes the LO output. Therefore, when the external load 101 is in a connection fault and the output control circuit diagnostic signal 115 becomes the LO, the cut-off transistor 109 is disconnected, thereby cutting off the current path of the external load 101 and preventing the external load 101 from being in a connection fault.

[0063] Example 4

[0064] Reference Figure 5 The electronic control device of Embodiment 4 of the present invention is described. Figure 5 This is a schematic diagram of the electronic control device in this embodiment. Figure 5 As shown, the electronic control unit (ECU) 100 of this embodiment is different from that of Embodiment 1 ( Figure 1 Instead of outputting the control device diagnostic signal 114 from the control device 102, the control device diagnostic signal 114 is directly input from the external signal of the electronic control unit (ECU) 100.

[0065] Additionally, the control device diagnostic signal 114 can also be transmitted via embodiment 2 ( Figure 3 The filter circuit 120 is configured to input the NOR circuit 106.

[0066] As described above, the electronic control unit (ECU) 100 of this embodiment uses an external signal 113 (e.g., a vehicle collision signal) input from the outside as a diagnostic signal (control unit diagnostic signal 114) for the control unit 102.

[0067] The external controller (not shown) of the electronic control unit (ECU) 100 can forcibly disconnect the on state of the external load 101.

[0068] Example 5

[0069] Reference Figure 6 The electronic control device of Embodiment 5 of the present invention is described. Figure 6 This is a schematic diagram of the electronic control device in this embodiment.

[0070] In each of Embodiments 1 to 4, the external load 101 is configured such that a current flows to an external GND 111 of a vehicle or the like through the external load switching element 103, but as shown in Figure 6 the electronic control device (ECU) 100 of the present embodiment is configured to control the external load 101 by supplying the ECU power VB 121 of the electronic control device (ECU) 100 to the external load 101.

[0071] When the external load switching element 103 is on, the ECU power VB 121 is supplied to the external load 101, so the output control circuit diagnosis signal 115 becomes LO through the NOT circuit 122. When the control device diagnosis signal 114 is LO, the NOR circuit 106 becomes HI.

[0072] In addition, the control device diagnosis signal 114 can also be configured to use the external signal 113 as in Embodiment 4.

[0073] The HI input of the NOR circuit 106 is held by the output holding circuit 107, so the cutoff transistor 109 is turned off, and thus the connection of the battery voltage VBAT 110 and the ECU power VB 121 is cut off. Since the power supply of the ECU power VB 121 is cut off, the output of the external load 101 is cut off, and thus the external load 101 is cut off.

[0074] As shown in Figure 6 the diagnosis circuit of the electronic control device (ECU) 100 of the present embodiment is configured such that the diagnosis signal (output control circuit diagnosis signal 115) of the control circuit that controls the external load 101 to the internal power voltage (ECU power VB 121) through the external load switching element 103 is input to the NOR circuit 106 via the NOT circuit 122, the diagnosis signal (control device diagnosis signal 114) of the control device 102 is input to the NOR circuit 106, and the connection of the internal power system (ECU power VB 121) and the external power system (battery voltage VBAT 110) is cut off by the cutoff transistor 109 according to the output signal of the NOR circuit 106 held by the output holding circuit 107.

[0075] Embodiment 6

[0076] Referring to Figure 7 the electronic control device of Embodiment 6 of the present application will be described. Figure 7 is a schematic configuration diagram of the electronic control device of the present embodiment. As shown in Figure 7 the electronic control device (ECU) 100 of the present embodiment is configured to control the external load 101 by supplying the ECU power VB 121 of the electronic control device (ECU) 100 to the external load 101. Figure 6To control the diagnostic signal 114, a filter circuit 120 was added. This filter circuit 120 uses filter capacitors 104 and 118, filter resistors 105 and 117, and filter diode 116, etc. Other configurations are the same as in Embodiment 5. Figure 6 )same.

[0077] like Figure 7 As shown, the electronic control unit (ECU) 100 of this embodiment includes a filter circuit 120, which is composed of filter capacitors 104 and 118, filter resistors 105 and 117, and filter diode 116. The PWM output from the control unit 102 is passed through the filter circuit 120 to remove the DC component output from the control unit 102, and is then input to the NOR circuit 106 as a diagnostic signal (control unit diagnostic signal 114) of the control unit 102.

[0078] Even if the control device output signal 119 is fixed as HI output due to a vehicle collision or the like, if the method of this embodiment is used, the control device diagnostic signal 114c becomes LO, so it can be cut off even if the external load 101 is in a faulty state.

[0079] Example 7

[0080] Reference Figure 8 The electronic control device of Embodiment 7 of the present invention is described below. Figure 8 This is a schematic diagram of the electronic control device in this embodiment. Figure 8 As shown, the electronic control unit (ECU) 100 in this embodiment is different from that in embodiment 5 ( Figure 6 A filter circuit 120 is added between the microcontroller or other control device 102 and the external load switching element 103. Additionally, an AND circuit 123 is connected instead of Embodiment 5. Figure 6 The NOR circuit 106 and NOT circuit 122 are described. Other configurations are the same as in Embodiment 5. Figure 6 )same.

[0081] like Figure 8As shown, the electronic control device (ECU) 100 of the present embodiment is provided with a filter circuit 120 composed of filter capacitors 104, 118, filter resistors 105, 117, and a filter diode 116, which is connected between the control device 102 and the external load switching element 103, and a diagnosis circuit that is an AND circuit 123, and the PWM output from the control device 102 is passed through the filter circuit 120, whereby the DC component output from the control device 102 is removed, and the control device diagnosis signal 114 is input to the AND circuit 123 as a diagnosis signal of the control device 102, and the output signal of the AND circuit 123 held by the output holding circuit 107 is used to cut off the connection between the internal power supply system (ECU power supply VB 121) and the external power supply system (battery voltage VBAT 110) by the cut-off transistor 109.

[0082] By PWM output from the control device output signal 119, the gate voltage of the external load switching element 103 becomes LO, the external load switching element 103 is turned on, and the external load 101 can be turned on.

[0083] Even in the case where the control device output signal 119 is fixed to LO or HI output due to a failure of the internal circuit of the electronic control device (ECU) 100 or the like, the external load switching element 103 is not turned on, and thus the external load 101 can be prevented from being turned on in error.

[0084] In addition, when the control device 102 does not control the external load switching element 103, the control device diagnosis signal 114 becomes HI output, and thus in the case where the external load 101 is in a turn-on failure and the output control circuit diagnosis signal 115 is HI, the AND circuit 123 outputs HI, the output holding circuit 107 holds the HI output, and the cut-off transistor 109 cuts off, and thus the current path of the external load 101 can be cut off, and the turn-on failure of the external load 101 can be prevented.

[0085] In addition, the diagnosis circuits (NOR circuit 106, NOT circuit 122, AND circuit 123) and the output holding circuit 107 described in each of the above embodiments are preferably semiconductor elements in which at least these circuits are formed on the same semiconductor chip. By forming the diagnosis circuits and the output holding circuit 107 on the same semiconductor chip, the wiring delay between the two circuits can be eliminated, and the cut-off transistor 109 can act without delay.

[0086] In addition, the present application is not limited to the above-described embodiments, and various modifications are included. For example, the above-described embodiments are detailed descriptions for facilitating understanding of the present application, and are not necessarily limited to having all the configurations described. In addition, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, or a part of the configuration of one embodiment can be added with the configuration of another embodiment. In addition, a part of the configuration of each embodiment can be subjected to addition, deletion, or replacement of other configurations.

[0087] Symbol explanation

[0088] 100... Electronic control device (ECU), 101... External load, 102... Control device (microcontroller, etc.), 103... External load switching element, 104... Capacitor for filter, 105... Resistor for filter, 106... NOR circuit, 107... Output holding circuit, 108... Charge extraction transistor, 109... Shutoff transistor, 110... Battery voltage (VBAT), 111... External GND (vehicle GND) of vehicle, etc., 112... ECU internal GND (ECU GND), 113... External signal (collision signal), 114... Control device diagnosis signal, 115... Output control circuit diagnosis signal, 116... Diode for filter, 117... Resistor for filter, 118... Capacitor for filter, 119... Control device output signal (microcontroller, etc.), 120... Filter circuit, 121... ECU power supply (VB), 122... NOT circuit, 123... AND circuit.

Claims

1. An electronic control device, characterized in that, have: An external load switching element that drives an external load; Control device that drives the external load switching element; A cut-off transistor that cuts off the connection between the internal GND and the external GND or the connection between the internal power system and the external power system. The diagnostic circuit takes the diagnostic signal from the control circuit that controls the external load through the external load switching element and the diagnostic signal from the control device as inputs, and outputs the diagnostic result. as well as An output holding circuit holds the output signal of the diagnostic circuit. The electronic control device, based on the signal held by the output holding circuit, disconnects the connection between the internal GND and the external GND, or the connection between the internal power supply system and the external power supply system, via the disconnection transistor. The diagnostic circuit is a NOR circuit. The diagnostic signal from the control circuit that controls the external load to GND via the external load switching element, and the diagnostic signal from the control device, are input to the NOR circuit. The connection between the internal GND and the external GND is cut off by the cutoff transistor based on the output signal of the NOR circuit held by the output holding circuit.

2. The electronic control device according to claim 1, characterized in that, The connection fault of the external load is detected based on the diagnostic signal of the control circuit that controls the external load through the external load switching element and the diagnostic signal of the control device.

3. The electronic control device according to claim 1, characterized in that, It has a filter circuit consisting of capacitors, resistors, and diodes. The PWM output from the control device is passed through the filter circuit to remove the DC component output from the control device, and then input as a diagnostic signal from the control device to the diagnostic circuit.

4. The electronic control device according to claim 3, characterized in that, By adjusting the capacitor and resistor-based time constant of the filter circuit, the time from when the PWM output from the control device stops to when the connection between the internal GND and the external GND or the connection between the internal power system and the external power system is cut off.

5. The electronic control device according to claim 3, characterized in that, The filter circuit is connected between the control device and the diagnostic circuit or between the control device and the external load switching element.

6. The electronic control device according to claim 1, characterized in that, The diagnostic signals of the control device use external signals input from the outside.

7. The electronic control device according to claim 6, characterized in that, The external signal is the vehicle's collision signal.

8. The electronic control device according to any one of claims 1 to 7, characterized in that, At least the diagnostic circuit and the output holding circuit are formed on the same semiconductor chip.

9. An electronic control device, characterized in that, have: An external load switching element that drives an external load; Control device that drives the external load switching element; A cut-off transistor that cuts off the connection between the internal GND and the external GND or the connection between the internal power system and the external power system. The diagnostic circuit takes the diagnostic signal from the control circuit that controls the external load through the external load switching element and the diagnostic signal from the control device as inputs, and outputs the diagnostic result. as well as An output holding circuit holds the output signal of the diagnostic circuit. The electronic control device, based on the signal held by the output holding circuit, disconnects the connection between the internal GND and the external GND, or the connection between the internal power supply system and the external power supply system, via the disconnection transistor. The diagnostic circuit consists of a NOT circuit and a NOR circuit. The diagnostic signal from the control circuit that controls the external load to the internal power supply voltage via the external load switching element is input to the NOR circuit via the NOT circuit, and the diagnostic signal from the control device is input to the NOR circuit. Based on the output signal of the NOR circuit held by the output holding circuit, the connection between the internal power system and the external power system is disconnected by the cut-off transistor.

10. The electronic control device according to claim 9, characterized in that, It has a filter circuit consisting of capacitors, resistors, and diodes. The PWM output from the control device is passed through the filter circuit to remove the DC component output from the control device, and then input to the NOR circuit as a diagnostic signal of the control device.

11. The electronic control device according to claim 9 or 10, characterized in that, At least the diagnostic circuit and the output holding circuit are formed on the same semiconductor chip.

12. An electronic control device, characterized in that, have: An external load switching element that drives an external load; Control device that drives the external load switching element; A cut-off transistor that cuts off the connection between the internal GND and the external GND or the connection between the internal power system and the external power system. The diagnostic circuit takes the diagnostic signal from the control circuit that controls the external load through the external load switching element and the diagnostic signal from the control device as inputs, and outputs the diagnostic result. as well as An output holding circuit holds the output signal of the diagnostic circuit. The electronic control device, based on the signal held by the output holding circuit, disconnects the connection between the internal GND and the external GND, or the connection between the internal power supply system and the external power supply system, via the disconnection transistor. It has a filter circuit consisting of capacitors, resistors, and diodes. The filter circuit is connected between the control device and the external load switching element, and the diagnostic circuit is an AND circuit. The PWM output from the control device is passed through the filter circuit to remove the DC component from the control device output, and then input as a diagnostic signal from the control device to the AND circuit. Based on the output signal of the AND circuit held by the output holding circuit, the connection between the internal power system and the external power system is disconnected by the cut-off transistor.

13. The electronic control device according to claim 12, characterized in that, At least the diagnostic circuit and the output holding circuit are formed on the same semiconductor chip.

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