JP2012020710A - Vehicle ecu - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vehicle electronic control unit (ECU) for minimizing electric power consumption when the operation of an internal microcomputer is not required.SOLUTION: A power source IC4 switches from a normal operation mode to a microcomputer off mode when "L" is given to an input part VC and the microcomputer 1 directs the microcomputer off mode and thereby, an operation power V4 supplied from a power source output part VO1 to the microcomputer 1 is stopped and the power is supplied to a power input part VCC of an external change detection part 3 from the power out put part VO2. The power source IC4, in the microcomputer off mode, switches from the microcomputer off mode to the normal operation mode when an input terminal P1 of CPU 42 receives the detection signal SS receiving from the external change detection part 3 and the detection signal SS directs the starting factor change to be the starting factor of the microcomputer 1.

Description

  The present invention relates to an in-vehicle ECU (Electronic Control Unit) mounted on a vehicle.

  2. Description of the Related Art Conventionally, a vehicle has a plurality of electronic devices called vehicle-mounted ECUs. Each vehicle-mounted ECU exchanges information via a network such as a CAN (Controller Area Network) so that the vehicle travels. And the control related to the comfort of the passenger compartment. Each on-vehicle ECU is connected to a power source such as a battery or an alternator of the vehicle via a power line and is operated by power supplied from the power source. In recent years, since the number of in-vehicle ECUs mounted on a vehicle is increasing, power saving is required.

  Along with the enhancement of the functions of vehicles, a large number of high-performance microcomputers (hereinafter abbreviated as “microcomputers”) have been mounted on in-vehicle ECUs. Driving these microcomputers increases power consumption and dark current, which contributes to battery exhaustion and fuel consumption deterioration. Therefore, the microcomputer mode is changed to the HALT mode (mode for interrupting CPU instruction execution) or STOP mode (mode for stopping the operation of the CPU and peripheral circuits), and the above-described HALT mode (STOP mode) is inserted into the normal mode. The normal mode operation by the microcomputer is generally performed intermittently.

  Moreover, as a vehicle-mounted ECU that can reduce power consumption, for example, a drive control device for a vehicle-mounted device disclosed in Patent Document 1 can be cited. The control device is provided with an approach sensor for detecting an object approaching the vehicle, and the controller intermittently turns on the switch to drive the approach sensor intermittently. When the controller detects the object approaching the vehicle by the proximity sensor when the proximity sensor is intermittently driven, the controller starts driving the intrusion sensor to be driven that has been stopped until then.

Japanese Patent No. 4149879

  However, in the microcomputer HALT mode or STOP mode, the main operation of the microcomputer is stopped, but since power is always supplied to the microcomputer itself, non-zero power is consumed even during the HALT mode and the STOP mode. There was a problem that it would be.

  The same applies to the control device disclosed in Patent Document 1. That is, the controller (equivalent to the microcomputer) that drives the proximity sensor and the intrusion sensor and the security ECU that controls the controller are always supplied with power, and there is a problem that power consumption cannot be suppressed in this respect. .

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain an in-vehicle ECU that minimizes power consumption when the operation of an internal microcomputer is unnecessary.

  According to a first aspect of the present invention, the in-vehicle ECU is in an operating state when operating power is supplied, and when the predetermined condition is satisfied during operation, the microcomputer sets the microcomputer OFF mode, and the microcomputer operates in the normal mode when the operation is performed. A power supply unit that supplies power and stops supplying the operating power to the microcomputer when the microcomputer OFF mode is set, and the external input information that indicates external input content related to the vehicle when the microcomputer OFF mode is set An external change detection unit that detects a start factor change to be a start factor of the microcomputer and outputs a detection signal; and the power source unit is configured to detect the start factor of the external input information when the microcomputer OFF mode is set. When instructing a change, change the microcomputer OFF mode setting to the normal mode setting. It is a symptom.

  A second aspect of the present invention is an in-vehicle ECU according to the first aspect, wherein the power supply unit includes a communication unit capable of transmitting and receiving with an external communication line, and the microcomputer is configured to transmit data to and from the communication unit. The predetermined condition includes a combination condition of a first condition related to the received content of the communication unit and a second condition in the microcomputer, and the communication unit is configured to perform the normal operation from the microcomputer OFF mode. It has a mode conversion function that can be changed to an operation mode.

  A third aspect of the present invention is an in-vehicle ECU according to the first or second aspect, wherein the external input information includes a plurality of partial external input information, and each of the external change detection units is in an operating state. A plurality of partial external change detection units for detecting the activation factor change in the partial external input information corresponding to time and outputting partial detection signals, and at least one detection for performing signal conversion processing on the corresponding partial detection signals A signal conversion unit, wherein the detection signal includes the plurality of partial detection signals after the signal conversion processing, and the plurality of partial detection signals after the signal conversion processing are caused by predetermined signal changes that are common to each other. Instructing the activation factor change of the corresponding partial external input information.

  The present invention of claim 4 is the in-vehicle ECU according to claims 1 to 3, wherein the microcomputer has a nonvolatile memory therein, receives the external input information, and sets the microcomputer OFF mode when the microcomputer is set to the OFF mode. The external input information is written to the nonvolatile memory, and the microcomputer compares the external input information newly received at the start of supply of the operating power with the external input information read from the nonvolatile memory, If there is no change, the microcomputer OFF mode is set.

  The power supply unit according to the first aspect of the present invention changes the microcomputer OFF mode setting to the normal mode setting when the detection signal indicates a change in activation factor of the external input information when the microcomputer OFF mode is set.

  Therefore, when the microcomputer OFF mode is set, the operation power supply to the microcomputer is completely stopped and the power consumption of the microcomputer is suppressed to “0”, and the microcomputer can be appropriately returned to the operating state when necessary. Play.

  According to the present invention of claim 2, the microcomputer OFF mode is set by external information (first condition) in addition to the internal factor (second condition) of the microcomputer, and the microcomputer OFF mode setting is changed to the normal mode setting. Can be set to cancel.

  In the present invention of claim 3, even if the instruction contents of the activation factor change are different between the plurality of partial detection signals before the signal conversion processing by at least one detection conversion unit, after the signal conversion processing, A change in activation factor of the corresponding partial external input information is instructed by a common predetermined signal change.

  As a result, even if the plurality of partial detection signals after the signal conversion processing are configured to be commonly input to one input terminal of the power supply unit, a plurality of partial detection signals are generated based on the predetermined signal change of the signal obtained at the input terminal. Since the activation factor change in any of the partial external input information can be reliably recognized, the input terminals for a plurality of partial detection signals to the power supply unit can be minimized.

  5. The microcomputer according to claim 4, wherein the microcomputer compares the newly received external input information with the external input information read from the non-volatile memory at the start of supply of operating power. The OFF mode is set.

  Therefore, even if the power supply unit erroneously sets the normal mode due to the influence of noise or the like of the external input information, the microcomputer can return to the microcomputer OFF mode setting again. As a result, after the microcomputer OFF mode, the microcomputer 1 can be returned to the normal mode only when the activation factor change actually occurs in the external input information.

It is a block diagram which shows the internal structure of vehicle-mounted ECU which is Embodiment 1 of this invention. FIG. 3 is a circuit diagram showing an internal configuration of an external change detection unit according to the first embodiment. 4 is a flowchart illustrating a process of shifting to a microcomputer OFF mode of the in-vehicle ECU according to the first embodiment. It is a block diagram which shows the internal structure of vehicle-mounted ECU which is Embodiment 2 of this invention. FIG. 5 is a circuit diagram showing an internal configuration of a conversion circuit shown in FIG. 4. It is a block diagram which shows the internal structure of in-vehicle ECU which is Embodiment 3 of this invention. 10 is a flowchart illustrating a process of shifting to a microcomputer OFF mode of the in-vehicle ECU according to the third embodiment. It is a flowchart which shows the initial operation of the microcomputer 1X immediately after power ON.

<Embodiment 1>
FIG. 1 is a block diagram showing the internal configuration of an in-vehicle ECU that is Embodiment 1 of the present invention. The in-vehicle ECU 10 according to the first embodiment includes a microcomputer 1, an external change detection unit 3, and a power supply IC 4 (power supply unit).

  The microcomputer 1 has an internal oscillator 11, a CPU 12, and a nonvolatile RAM 15 inside. The microcomputer 1 is in an operating state when the operating power supply V4 is supplied to the power input unit VCC, and the CPU 12 operates with a clock generated by the internal oscillator 11 in the operating state, and is detected by a switch group (not shown) under the control of the CPU 12. When an external input is monitored and an external input is detected from any of the switch groups, predetermined operation control is performed according to the detected external input content. Note that the switch group only needs to capture environmental changes in the vehicle as an external input, and includes sensors as well as general switches such as power window switch inputs.

  Further, the CPU 12 performs a process of checking the contents of the discrimination data CD read from the nonvolatile RAM 15 when the discrimination data CD is transferred to the microcomputer OFF mode and when the power is turned on.

  The power supply IC 4 includes an internal oscillator 41, a CPU 42, and a communication unit 46 inside. The CPU 42 operates with a clock generated by the internal oscillator 41 in the operating state.

  In the normal mode, the power supply IC 4 converts the external power supply EVC from the power supply line LVC from the power supply input section VI and supplies the operation power supply V4 from the power supply output section VO1 to the power supply input section VCC of the microcomputer 1. At this time, power supply from the power output unit VO2 to the power input unit VCC of the external change detecting unit 3 is not performed.

  The power supply IC 4 is connected to the control input section VC with the power control terminal PV of the microcomputer 1. When the control input section VC is “L”, the normal operation mode is switched to the microcomputer OFF mode, and the operation power supply V 4 from the power output section VO 1 is switched. Stop supplying. At this time, power is supplied from the power output unit VO2 to the power input unit VCC of the external change detecting unit 3.

  The power supply IC 4 receives the detection signal S3 received from the external change detection unit 3 at the input terminal PI of the CPU 42 in the microcomputer OFF mode, and changes from the microcomputer OFF mode to the normal operation mode based on the detection signal S3 under the control of the CPU 42.

  The communication unit 46 can communicate with other external vehicle-mounted ECUs and the like via the communication line 9. As the communication unit 46 and the communication line 9, for example, a CAN (Controller Area Network) IC and a CAN communication line (CAN-H, CAN-L) can be considered. The communication unit 46 can exchange data with the communication terminal PT of the microcomputer 1.

  The communication unit 46 detects whether or not a sleep condition such as “there is no signal input from the communication line 9 for a predetermined period of time” is established, and instructs the establishment of the sleep condition when the establishment of the sleep condition (first condition) is detected. Information D46 is output to the communication terminal PT of the microcomputer 1.

  Furthermore, when the communication unit 46 detects a communication unit activation factor during operation in the microcomputer OFF mode, the communication unit 46 is changed to the normal operation mode under the control of the CPU 42.

  In the microcomputer OFF mode, the external change detection unit 3 is supplied with power from the power output unit VO2 of the power supply IC 4 to the power input unit VCC and enters an operating state.

  FIG. 2 is a circuit diagram showing an internal configuration of the external change detection unit 3. As shown in the figure, the external change detection unit 3 includes a plurality of switch groups SW1 to SWn and a logic circuit 35. The switch groups SW1 to SWn have basically the same configuration as that of the switch group used in the microcomputer 1, and are turned on / off according to external input contents indicating environmental changes in the vehicle. For example, when the switch SW1 is a door switch, the door is in the “open” / door “closed” state and is in the ON / OFF state. That is, the ON / OFF state of the switch groups SW1 to SWn is external input information indicating the external input content related to the vehicle.

  One end of each of the switch groups SW1 to SWn is grounded, and the other end is commonly connected to the power supply input unit VCC via the pull-up resistors R1 to Rn. The wirings L1 to Ln on the other end side of the switch groups SW1 to SWn are connected to the input of the logic circuit 35.

  The logic circuit 35 receives signals from the wirings L1 to Ln. When all of the wirings L1 to Ln are “H”, the logic circuit 35 is “L”, and when any of the wirings L1 to Ln is “L” (switch groups SW1 to SWn). The detection signal S3 which becomes "H" is output. Therefore, by detecting the rising edge of the detection signal S3 from “L” to “H”, any of the switch groups SW1 to SWn can be detected from the OFF state to the ON state.

  Here, any one of the switch groups SW1 to SWn is set so that a change from the OFF state to the ON state becomes a start factor change to be a start factor of the microcomputer 1 in the power OFF state in the microcomputer OFF mode.

  As described above, the external change detection unit 3 performs the “H” rising change that changes the detection signal S3 from “L” to “H” when any of the switch groups SW1 to SWn changes from the OFF state to the ON state. By presenting, it is possible to instruct the activation factor change to be the activation factor of the microcomputer 1 in the external input information (ON / OFF state of the switch groups SW1 to SWn) by the detection signal S3.

  FIG. 3 is a flowchart showing a process of shifting to the microcomputer OFF mode of the in-vehicle ECU 10 according to the first embodiment.

  First, in step ST21, when the communication unit 46 of the power supply IC 4 detects that the sleep condition (first condition) on the communication line 9 is satisfied (Yes), the process proceeds to step ST22. On the other hand, when the sleep condition is not satisfied (No), step ST21 is repeated, and the vehicle-mounted ECU 10 continues normal operation.

  In step ST22 executed when Yes in step ST21, the communication unit 46 outputs the communication unit information D46 instructing the establishment of the sleep condition to the communication terminal PT of the microcomputer 1.

  In step ST23, when the microcomputer 1 recognizes that a predetermined power-off condition (second condition) that is an unnecessary determination condition of the microcomputer 1 is satisfied (Yes), the microcomputer 1 performs a step to shift from the normal operation mode to the microcomputer OFF mode. The process proceeds to ST24 and subsequent processes. That is, when the combination condition including the first and second conditions is satisfied, the process proceeds to step ST24 and subsequent steps.

  On the other hand, when the predetermined power-off condition is not satisfied (No), the process returns to step ST21 and the vehicle-mounted ECU 10 continues the normal operation.

  In step ST24, which is executed in the case of Yes in step ST23, the microcomputer 1 sets the determination data CD to be written in the non-volatile RAM 15 to the set state (indicating the microcomputer OFF mode) as a preparation process for moving to the power OFF state. Data CD writing processing is executed.

  Next, in step ST25, the microcomputer 1 sets the power control terminal PV (microcomputer output signal S1) to "L" and instructs the power supply IC 4 to change from the normal operation mode to the microcomputer OFF mode.

  Thereafter, in step ST26, the power supply IC 4 stops supplying the operating power V4 of the microcomputer 1, and the microcomputer 1 is turned off.

  Thereafter, the microcomputer 1 completely stops operating. The power supply IC 4 monitors the detection signal S3 of the external change detection unit 3, and maintains the microcomputer OFF mode until detecting "H" rise of the detection signal S3 (change in activation factor in external input information by the switch groups SW1 to SWn). The microcomputer 1 is in a power OFF state.

  Then, when the power supply IC 4 detects the “H” rising of the detection signal S3, the microcomputer OFF mode is changed to the normal operation mode, the supply of the operation power supply V4 to the microcomputer 1 is resumed, and the microcomputer 1 is returned to the operation state.

  On the other hand, the communication unit 46 in the power supply IC 4 determines whether or not there is a communication unit activation factor based on a signal obtained from the communication line 9 alone.

  Therefore, when the communication unit 46 determines the communication unit activation factor in the microcomputer OFF mode, the determination result is notified to the CPU 42, so that the normal operation mode is changed under the control of the CPU 42, and the operation power to the microcomputer 1 is changed. The supply of V4 can be resumed.

  Immediately after the power is turned on, the microcomputer 1 selects whether or not to execute the reset start (operation) depending on whether or not the determination data CD read from the nonvolatile RAM 15 is set and returns to the normal operation. .

  As described above, when the detection signal S3 instructs the activation factor change of the external input information by the switch groups SW1 to SWn, or when the communication unit 46 instructs the communication unit activation factor, the power supply IC 4 is turned off by the microcomputer under the control of the CPU 42. Change from mode to normal operation mode.

  Accordingly, since the power supply IC 4 completely cuts off the supply of the operating power supply V4 to the microcomputer 1 when the microcomputer OFF mode is set, the power consumption of the microcomputer 1 when the microcomputer OFF mode is set can be suppressed to “0”. The power supply IC 4 monitors the detection signal S3 to detect a change in activation factor to be an activation factor in the external input information (ON / OFF state of the switch groups SW1 to SWn) indicating the external input content related to the vehicle. Therefore, the microcomputer OFF mode can be changed to the normal operation mode at an appropriate timing.

  The CPU 12 of the microcomputer 1 has a larger circuit configuration than the CPU 42 of the power supply IC 4, and the power consumption of the microcomputer 1 occupies a major proportion of the power consumption of the entire in-vehicle ECU 10. Therefore, the power consumption is suppressed to “0” in the microcomputer OFF mode. As a result, it is possible to effectively reduce the power consumption of the in-vehicle ECU 10 as a whole.

  In addition, when the power supply IC 4 of the on-vehicle ECU 10 of the first embodiment detects a change in activation factor based on the detection signal S3 when the microcomputer OFF mode is set, the power supply IC 4 alone returns from the microcomputer OFF mode setting to the normal mode setting. can do.

  Furthermore, the power supply IC 4 of the in-vehicle ECU 10 according to the first embodiment can set the microcomputer OFF mode based on external information obtained from the communication line 9 by the communication unit 46 in addition to the internal factors of the microcomputer 1.

  In addition, even when the communication activation factor is determined by the communication unit 46, the power IC 46 alone can return to the normal operation mode regardless of the microcomputer 1. That is, the communication unit 46 has a mode conversion function capable of changing the setting from the microcomputer OFF mode to the normal operation mode by notifying the CPU 42 of the communication activation factor determination.

  That is, in addition to the internal factor of the microcomputer 1 (second condition), the microcomputer OFF mode is set according to external information (first condition), and the cancel setting from the microcomputer OFF mode setting to the normal mode setting is performed. Can do.

  The external change detection unit 3 is supplied with power from the power supply IC 4 only in the microcomputer OFF mode, but may be configured to always receive power. That is, the external change detection unit 3 may be in an operating state at least in the microcomputer OFF mode.

<Embodiment 2>
FIG. 4 is a block diagram showing an internal configuration of an in-vehicle ECU according to Embodiment 2 of the present invention. The in-vehicle ECU 20 of the second embodiment has a microcomputer 1, an external change detection unit 3X, and a power supply IC 4 inside. Since the internal configurations of the microcomputer 1 and the power supply IC 4 are the same as those in the first embodiment, the same reference numerals are given and description thereof is omitted as appropriate. Further, the processing contents of the in-vehicle ECU 20 for shifting to the microcomputer OFF mode and the returning contents from the microcomputer OFF mode to the normal operation mode are the same as those in the in-vehicle ECU 10 of the first embodiment. However, the difference is that the external change detector 3 is replaced with an external change detector 3X described later.

  The external change detection unit 3X includes partial external change detection units 31 to 33 and conversion circuits 51 and 52 (detection signal conversion units). The partial external change detection unit 31 outputs a detection signal S31 in which “H” rising change appears when the activation factor of the internal switch (group) changes. The partial external change detection unit 32 outputs a detection signal S32 in which an “L” falling change appears when the activation factor of the internal switch (group) changes. The partial external change detection unit 33 outputs a detection signal S33 in which an “H” pulse (“H” rises, followed by a “L” fall after a predetermined period after the rise of “H”) appears when the activation factor of the internal switch (group) changes. Thus, the signal change contents instructing the activation factor change are different between the detection signals S31 to S33 of the partial external change detection units 31 to 33.

  The conversion circuit 51 receives the detection signal S31, performs signal conversion processing on the detection signal S31, and outputs a converted detection signal S51. The conversion circuit 52 receives the detection signal S32, performs signal conversion processing on the detection signal S32, and outputs a converted detection signal S52. In the post-conversion detection signals S51 and S52, an “H” pulse appears when the activation factor changes.

  FIG. 5 is a circuit diagram showing the internal configuration of the conversion circuits 51 and 52 shown in FIG. As shown in the figure, the conversion circuit 51 includes a delay circuit 53, an inverter 54, and an AND gate 55. The AND gate 55 receives a detection signal S31 at one input, and receives a signal obtained from the detection signal S31 via the delay circuit 53 and the inverter 54 at the other input. The output signal of the AND gate 55 becomes the converted detection signal S51. Therefore, the post-conversion detection signal S51 generates an “H” pulse that becomes “H” in the delay time Δ53 of the delay circuit 53 from the “H” rise of the detection signal S31. That is, in the post-conversion detection signal S51, the “H” pulse appears when the activation factor changes as described above.

  On the other hand, the conversion circuit 52 includes an inverter 56, a delay circuit 57, and an AND gate 58. The AND gate 58 receives a signal obtained from the detection signal S32 via the inverter 56 at one input, and receives a signal obtained from the detection signal S32 via the delay circuit 57 at the other input. The output signal of the AND gate 58 becomes the post-conversion detection signal S52. Therefore, the post-conversion detection signal S52 generates an “H” pulse that becomes “H” in the delay time Δ57 of the delay circuit 57 from the “L” falling edge of the detection signal S32. That is, in the post-conversion detection signal S52, the “H” pulse appears when the activation factor changes as described above.

  Returning to FIG. 4, the post-conversion detection signals S51 and S52 and the detection signal S33 are commonly provided to the input terminal PI of the CPU 42 of the power supply IC 4 as the detection signal S3. In the figure, a wired OR is assumed, but the converted detection signals S51 and S52 and the detection signal S33 are received by a three-input OR gate, and the output of the OR gate is given to the input terminal PI as a detection signal S3. Anyway.

  The in-vehicle ECU 20 according to the second embodiment includes signal change contents (“H” rising, “L” falling, “H”) instructing a change in activation factor between the detection signals S31 to S33 of the partial external change detection units 31 to 33. Even if the pulses are different from each other, after the signal conversion processing by the conversion circuits 51 and 52, the corresponding partial external input information (internal switch (group) Status) activation factor change.

  Therefore, even if the post-conversion detection signals S51 and S52 and the detection signal S33 are configured to be commonly input to the input terminal PI of the CPU 42 of the power supply IC 4, the CPU 42 can detect the “H” pulse of the signal obtained from the input terminal. Thus, it is possible to reliably recognize the activation factor change in any of the switches (groups) in the partial external change detection units 31 to 33. As a result, there is an effect that the number of input terminals for the detection signals S51 and S52 and the detection signal S33 after conversion to the electric power source IC4 can be suppressed to “1”.

  In general, the input terminal PI of the power supply IC 4 is limited to one or two, and one input terminal PI is required in response to detection of one type of signal change. In the configuration that directly receives the detection signals S31 to S33, at least three input terminals PI are required, but the in-vehicle ECU 20 of the second embodiment can suppress the number of input terminals PI to one.

<Embodiment 3>
FIG. 6 is a block diagram showing an internal configuration of an in-vehicle ECU according to Embodiment 3 of the present invention. The in-vehicle ECU 30 of the third embodiment includes a microcomputer 2, an external change detection unit 3 (3X), and a power supply IC 4 inside. Since the internal configuration of a part of the microcomputer 2, the external change detection unit 3 (3X), and the power supply IC 4 is the same as that of the first embodiment (second embodiment), the same reference numerals are given and description thereof is omitted as appropriate.

  The microcomputer 2 includes an internal oscillator 11, a CPU 12 and a nonvolatile RAM 15. The CPU 12 receives external input information XJ which is the state of the switch (group) in the external change detection unit 3. The CPU 12 writes the discrimination data CD and the external input information XJ to the nonvolatile RAM 15 at the time of the microcomputer OFF mode transition, the content check processing of the discrimination data CD at the time of power-on return, and the external input information XJ read from the nonvolatile RAM 15 Then, processing based on comparison with the external input information XJ fetched from the external change detection unit 3 is performed.

  FIG. 7 is a flowchart showing a process of shifting to the microcomputer OFF mode of the in-vehicle ECU 30 according to the third embodiment.

  As in the vehicle-mounted ECU 10 of the first embodiment, after passing through steps ST21 and ST22, in step ST23, when the microcomputer 2 recognizes the establishment of a predetermined power-off condition that is an unnecessary determination condition of the microcomputer 2 (Yes), normal operation is performed. In order to shift from the mode to the microcomputer OFF mode, the process proceeds to step ST24X and subsequent steps. On the other hand, when the predetermined power-off condition is not satisfied (No), the process returns to step ST21 and the in-vehicle ECU 30 continues the normal operation.

  In step ST24X, which is executed in the case of Yes in step ST23, similarly to step ST24 of the first embodiment, a process of writing the external input information XJ to the nonvolatile RAM 15 together with the determination data CD (set state) is executed. That is, the microcomputer 2 writes the external input information XJ obtained from the external change detector 3 in the nonvolatile RAM 15 in addition to the discrimination data CD.

  Thereafter, similarly to the first embodiment, after passing through step ST25, in step ST26, the power supply IC4 stops the supply of the operating power supply V4 of the microcomputer 2, and the microcomputer 2 is turned off.

  Thereafter, the microcomputer 2 completely stops operating. The power supply IC 4 monitors the detection signal S3 of the external change detection unit 3 and maintains the microcomputer OFF mode until the “H” rise with respect to the detection signal S3 is detected, and the microcomputer 2 is in the power OFF state.

  Then, when the power supply IC 4 detects the “H” rising of the detection signal S3, the microcomputer OFF mode is changed to the normal operation mode, the supply of the operation power supply V4 is resumed, and the microcomputer 2 is returned to the operation state.

  Instead of the external change detector 3, the external change detector 3X of the second embodiment may be used. In this case, the power supply IC 4 changes the microcomputer OFF mode to the normal operation mode when detecting the “H” pulse of the detection signal S3 of the external change detection unit 3X.

  Further, instead of the external change detection unit 3, a simple external change detection unit including the detection signals S31 to S33 of the partial external change detection units 31 to 33 in the external change detection unit 3X may be used. When a simple external change detection unit is used instead of the external change detection unit 3, the detection signals S31 to S33 are connected to the input terminal PI in common, and the CPU 42 of the power supply IC 4 has the signal “H” applied to the input terminal PI. Control is performed so as to return to the normal operation mode even if any signal change is detected among the rising, “L” falling and “H” pulses.

  Further, the communication unit 46 in the power supply IC 4 determines whether or not there is a communication unit activation factor based on a signal obtained from the communication line 9 alone.

  Therefore, in the microcomputer OFF mode, when the communication unit 46 determines the communication unit activation factor, the mode is changed to the normal operation mode under the control of the CPU 42.

  FIG. 8 is a flowchart showing the initial operation of the microcomputer 2 immediately after the power is turned on. Hereinafter, the procedure of the initial operation of the microcomputer 2 will be described with reference to FIG.

  First, in step ST31, the microcomputer 2 checks whether or not the discrimination data CD is in a set state. That is, the microcomputer 2 reads the determination data CD in the nonvolatile RAM 15, and when the determination data CD is in the set state (Yes), the microcomputer 2 proceeds to the processing after step ST32. On the other hand, if the determination data CD is not in the set state in step ST31 (No), a normal reset start is performed in step ST38. That is, the microcomputer 2 can accurately recognize whether or not the reset start should be performed by referring to the determination data CD stored in the non-volatile RAM 15 at the time of the power-on return from the power-off to the power-on. it can.

  The processes in steps ST31 and ST38 are also performed in the microcomputer 1 of the first and second embodiments. However, in Embodiment 1 and Embodiment 2, if Yes in step ST31, the process is immediately terminated.

  In step ST32 executed in the case of Yes in step ST31, the microcomputer 2 refers to the communication unit information D46 or the like so that the communication unit 46 determines the communication unit activation factor and returns to the normal operation mode (communication unit activation factor). Confirm whether or not. That is, if it is confirmed in step ST32 that the cause is a communication unit activation factor (Yes), the determination data CD is cleared in step ST39 and the process ends, and if it is confirmed that it is not a communication unit activation factor (No). Shifts to processing after step ST33.

  In step ST <b> 33 executed when No in step S <b> 32, the CPU 12 in the microcomputer 2 reads the external input information XJ from the nonvolatile RAM 15.

  Subsequently, in step ST34, the current external input information XJ is read from the external change detection unit 3.

  In step ST35, the external input information XJ and XJ read in steps ST33 and ST34 are compared to determine whether the external input information XJ has changed over time before setting the microcomputer OFF mode and after returning to the normal operation mode. If the input information XJ has changed with time (Yes), the discrimination data CD is cleared in step ST39, and the process is terminated.

  On the other hand, if the external input information XJ has not changed with time in step ST35 (No), the power supply control terminal PV is set to “L” in step ST36, the microcomputer 2 is turned off again in step ST37, and the microcomputer OFF mode is set. Return to.

  As described above, in the in-vehicle ECU 30 according to the third embodiment, the microcomputer 2 receives the external input information XJ newly received and the external read from the nonvolatile RAM 15 in the process after the transition to step ST33 during the initial operation after the power is turned on. When the input information XJ is compared and the external input information XJ does not change with time, the microcomputer OFF mode is set.

  Accordingly, even when the detection signal S3 input to the input terminal PI of the power supply IC 4 instructs a change in activation factor due to the influence of noise or the like, the microcomputer IC is erroneously set to the normal mode and the microcomputer 2 is turned on. When the external input information XJ does not change with time, it can be determined that the activation factor has not actually changed, and the microcomputer OFF mode can be set again.

  As a result, the in-vehicle ECU 30 of the third embodiment can operate in the normal operation mode by completely returning from the microcomputer OFF mode only when the activation factor change actually occurs in the external input information XJ.

1, 2 Microcomputer 3, 3X External change detector 4 Power supply IC
10, 20, 30 In-vehicle ECU
15 Nonvolatile RAM
31-33 Partial external change detection unit 51, 52 Conversion circuit

Claims (4)

A microcomputer that is in an operating state when operating power is supplied, and that sets a microcomputer OFF mode when a predetermined condition is satisfied during operation;
A power supply unit for supplying the operating power to the microcomputer at the time of normal mode setting, and stopping the supply of the operating power to the microcomputer at the time of setting the microcomputer OFF mode;
At the time of setting the microcomputer OFF mode, an external change detection unit that detects a start factor change to be a start factor of the microcomputer in external input information indicating external input content related to the vehicle and outputs a detection signal;
The power supply unit is changed from the microcomputer OFF mode setting to the normal mode setting when the detection signal indicates the activation factor change of the external input information when the microcomputer OFF mode is set.
In-vehicle ECU. An in-vehicle ECU according to claim 1,
The power supply unit is
Includes a communication unit that can send and receive with external communication lines,
The microcomputer can exchange data with the communication unit,
The predetermined condition includes a combination condition of a first condition related to the received content of the communication unit and a second condition inside the microcomputer,
The communication unit has a mode conversion function capable of changing the setting from the microcomputer OFF mode to the normal operation mode.
In-vehicle ECU. An in-vehicle ECU according to claim 1 or claim 2,
The external input information includes a plurality of partial external input information,
The external change detector is
A plurality of partial external change detection units that detect the activation factor change in the partial external input information corresponding to each operating state and output a partial detection signal, and perform signal conversion processing on the corresponding partial detection signal Including at least one detection signal converter,
The detection signal includes the plurality of partial detection signals after the signal conversion processing,
The plurality of partial detection signals after the signal conversion processing indicate the activation factor change of the corresponding partial external input information by a predetermined signal change common to each other,
In-vehicle ECU. An on-vehicle ECU according to claim 1 to claim 3,
The microcomputer has a nonvolatile memory inside, receives the external input information, writes the external input information to the nonvolatile memory when the microcomputer OFF mode is set,
The microcomputer compares the newly received external input information with the external input information read from the non-volatile memory at the start of supply of the operating power, and if there is no change in content, the microcomputer OFF mode setting is performed. Do,
In-vehicle ECU.

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