JP2009267258A - Solenoid drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detailedly check whether or not supply of power to a solenoid is blocked with an easy configuration. <P>SOLUTION: The solenoid drive includes a solenoid drive circuit that drives the solenoid, a relay circuit that supplies the power from a power supply to the solenoid drive circuit, a control means that controls power supply with the solenoid drive circuit and relay circuit, and a power storage means. The control means determines that blocking with the solenoid drive circuit is abnormal at least on a condition that the voltage of a power supply terminal becomes a predetermined first voltage or less until the predetermined first time has lapsed since it commands blocking that blocks the power supply with the solenoid drive circuit and relay circuit. In addition, the control means determines that blocking with the relay circuit is abnormal at least on a condition that a voltage value of the power supply terminal is kept bigger than that of a predetermined second voltage until the predetermined second time has lapsed since the blocking command is issued. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solenoid drive device, and more particularly to a solenoid drive device used in an electronic control device for a vehicle.

Patent Document 1 discloses a vehicle electronic control device used as a vehicle brake electronic device. This electronic control device for a vehicle is applied as a fluid pressure control device for a vehicle brake, and controls the brake fluid pressure using a solenoid. In this vehicle electronic control device, the solenoid is controlled by a microcomputer via a solenoid drive circuit, and when an abnormality of the microcomputer is detected, the relay circuit provided between the power source and the solenoid drive circuit is shut off, The power supply to the solenoid is shut off.
JP 2007-253930 A

  In the device for driving the solenoid by the microcomputer control as described above, it is preferable to provide a function for checking whether or not the power supply to the solenoid is surely cut off when an abnormality of the microcomputer is detected. Further, as a method for shutting off the power supply to the solenoid, it is conceivable to shut off the power supply in the relay circuit and to shut off the power supply in the solenoid drive circuit. Therefore, in order to check the interruption in detail, it is preferable to check the interruption in the relay circuit and the interruption in the solenoid drive circuit. However, if separate circuits are provided to check both the relay circuit and the solenoid drive circuit, the circuit configuration becomes complicated and the cost increases.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a solenoid drive device that can check in detail whether the power supply to the solenoid is cut off in a simple configuration.

  In order to solve the above problems, the present invention employs the following configuration. That is, the first invention is a solenoid drive device including a solenoid drive circuit, a relay circuit, a control means, and a power storage means. The solenoid drive circuit drives the solenoid by supplying power to the solenoid. The relay circuit supplies power from the power source to the solenoid drive circuit. The control means controls power supply by the solenoid drive circuit and the relay circuit. The power storage means is connected to the power supply end between the relay circuit and the solenoid drive circuit, and holds the voltage supplied from the relay circuit. Here, the control means determines that the voltage of the power supply terminal is equal to or lower than the predetermined first voltage after a predetermined first time elapses after the cutoff instruction for cutting off the power supply by the solenoid drive circuit and the relay circuit is performed. It is determined that the interruption by the solenoid drive circuit is abnormal, at least as a condition, and the voltage of the power supply terminal is a predetermined second during a predetermined second time after the interruption instruction is issued. It is determined that the interruption by the relay circuit is abnormal, at least on the condition that it is maintained at a value larger than the voltage.

  In the second invention, the first time may be set shorter than the second time.

  In the third invention, the power storage means holds the voltage supplied from the relay circuit at a voltage higher than the first voltage for at least a first time after the power supply from the relay circuit is cut off. It may have a possible capacitance.

  In the fourth invention, the power storage means has a capacitance at which the voltage held thereby becomes at least the second voltage or less when the second time has elapsed since the power supply from the relay circuit was cut off. It may be a thing.

  In the fifth invention, the control means may include drive control means, monitoring means, and shut-off means. The drive control means controls driving of the solenoid drive circuit and the relay circuit. The monitoring unit monitors an abnormality of the drive control unit. When the monitoring means detects an abnormality in the drive control means, the shut-off means gives a shut-off instruction to shut off the power supply by the solenoid drive circuit and the relay circuit regardless of the control by the drive control means.

  In a sixth aspect, the solenoid drive device may be mounted on a vehicle and use a vehicle battery as a power source. At this time, the solenoid driving device supplies predetermined power to the control means by power from the battery, and when the predetermined power cannot be supplied due to insufficient power supply from the battery, the power source for resetting the processing in the control means A circuit is further provided. The control means, after a predetermined third time has elapsed since the cutoff instruction was issued, and until a predetermined first time has elapsed since the cutoff instruction to cut off the power supply by the solenoid drive circuit and the relay circuit is issued On the condition that the voltage of the power supply terminal becomes equal to or lower than the predetermined first voltage during this period, it is determined that the interruption by the solenoid drive circuit is abnormal.

  In the seventh invention, when the predetermined power cannot be supplied, the power supply circuit may reset the processing in the control means until the third time elapses after the cutoff instruction is given.

  According to the first invention, by providing power storage means at the power supply end, when the interruption in the relay circuit is abnormal, when the interruption in the solenoid drive circuit is abnormal, and when the interruption in the two circuits is normal In each of the cases, the behavior of the time change of the voltage at the power supply end is different. Therefore, it is possible to check whether the interruption at the two locations of the relay circuit and the solenoid drive circuit is normal only by the voltage at the power supply end. That is, it is possible to check in detail with a simple configuration whether the power supply to the solenoid is interrupted.

  According to the second invention, the first time is set shorter than the second time. Here, if the elapsed time since the disconnection instruction is issued is too long, the check for shutoff by the solenoid drive circuit becomes inaccurate, and if the elapsed time is too short, the check for shutoff by the relay circuit becomes inaccurate. Therefore, as in the second invention, the determination can be made more accurately by making the first time shorter than the second time.

  According to the third aspect, by using the power storage means that satisfies the condition described in the third aspect, it is possible to accurately check the interruption by the solenoid drive circuit.

  According to the fourth aspect, by using the power storage means that satisfies the condition described in the fourth aspect, it is possible to accurately check the interruption by the relay circuit.

  According to the fifth aspect of the present invention, the power supply to the solenoid can be cut off when the drive control means becomes abnormal.

  According to the sixth invention, when the power supply from the battery is insufficient, the power supply circuit resets the processing in the control means, so that the processing is reset before the control means makes an erroneous determination. Judgment can be prevented. In particular, according to the seventh invention, when the power supply circuit cannot supply predetermined power, the process in the control means is reset before the third time elapses after the cutoff instruction is given, so that the erroneous determination is more reliably performed. Can be prevented.

(First embodiment)
Hereinafter, a solenoid driving apparatus according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the configuration of the solenoid drive device according to the first embodiment. As shown in FIG. 1, the solenoid drive device includes a microcomputer 1, a voltage detection circuit 2, a monitoring circuit 3, an output prohibition circuit 4, a relay drive circuit 5, a relay circuit 6, a capacitor 7, a first solenoid drive circuit 8a, a second A solenoid drive circuit 8b, a power supply circuit 10, a capacitor 11, and diodes 12 and 13 are provided to drive the first solenoid 9a and the second solenoid 9b that are driven by the solenoid drive device. The solenoid drive device is used, for example, in a brake hydraulic pressure control device in a vehicle in order to control the hydraulic pressure of a vehicle brake using the solenoids 9a and 9b. Hereinafter, the configuration of each part of the solenoid driving device will be described.

  First, a configuration for supplying a power supply voltage to each solenoid 9a and 9b will be described. In the present embodiment, the battery 14 as a power supply source supplies power to the solenoids 9a and 9b via the relay circuit 6 and the solenoid drive circuits 8a and 8b. The battery 14 is a battery mounted on a vehicle, for example. The relay circuit 6 is connected to the battery 14, and the solenoid drive circuits 8a and 8b are connected to the relay circuit 6 in parallel. The relay circuit 6 supplies electric power from the battery 14 to the solenoid drive circuits 8a and 8b. Hereinafter, one end of the relay circuit 6 connected to each solenoid drive circuit 8a and 8b is referred to as a power supply end. Hereinafter, the voltage BS at the power supply end, that is, the power supply voltage BS supplied to the solenoids 9a and 9b via the solenoid drive circuits 8a and 8b is referred to as a solenoid power supply voltage BS.

  Each solenoid 9a and 9b is connected to each solenoid drive circuit 8a and 8b so as to correspond to each solenoid drive circuit 8a and 8b on a one-to-one basis. In FIG. 1, one end of the solenoid 9a is connected to the solenoid drive circuit 8a, and one end of the solenoid 9b is connected to the solenoid drive circuit 8b. The other ends of the solenoids 9a and 9b are grounded. Each solenoid drive circuit 8a and 8b drives each solenoid 9a and 9b by supplying electric power to each solenoid 9a and 9b. In the present embodiment, the number of solenoid driving circuits and the number of solenoids driven by the present embodiment are two. However, the number of solenoid driving circuits and the number of solenoids may be any number.

  Next, the structure for controlling each solenoid 9a and 9b is demonstrated. The microcomputer 1 is information processing means for controlling the solenoids 9a and 9b. A voltage detection circuit 2, a monitoring circuit 3, an output inhibition circuit 4, and a power supply circuit 10 are connected to the microcomputer 1. The microcomputer 1 controls the solenoids 9a and 9b by outputting control signals to the relay drive circuit 5 and the solenoid drive circuits 8a and 8b via the output prohibition circuit 4. In the present embodiment, the microcomputer 1, the monitoring circuit 3, and the output prohibition circuit 4 control power supply by the solenoid drive circuits 8a and 8b and the relay circuit 6, and correspond to the control means described in the claims. To do. Specifically, the microcomputer 1 corresponds to the drive control means described in the claims, the monitoring circuit 3 corresponds to the monitoring means described in the claims, and the output prohibition circuit 4 corresponds to the interruption means described in the claims. .

  Specifically, the microcomputer 1 outputs a relay drive request signal RS to the relay drive circuit 5 via the output prohibition circuit 4. The relay drive circuit 5 is connected to the relay circuit 6. The relay drive circuit 5 controls the power supply by the relay circuit 6 from the battery 14 to the solenoid drive circuits 8a and 8b. When the relay drive request signal RS is input, the relay drive circuit 5 controls the relay circuit 6 so that power is supplied to the solenoid drive circuits 8a and 8b, and when the relay drive request signal RS is not input, The relay circuit 6 is controlled so as to cut off the power supply to the solenoid drive circuits 8a and 8b. Thus, the microcomputer 1 can cut off the power supply by the relay circuit 6 using the relay drive circuit 5.

  Further, the microcomputer 1 outputs solenoid drive request signals SS1 and SS2 to the solenoid drive circuits 8a and 8b via the output prohibition circuit 4. When the solenoid drive request signal SS1 is input, the first solenoid drive circuit 8a supplies power to the first solenoid 9a to drive the first solenoid 9a. When the solenoid drive request signal SS1 is not input, the first solenoid drive circuit 8a The power supply to 9a is cut off. Similarly, when the solenoid drive request signal SS2 is input, the second solenoid drive circuit 8b supplies power to the second solenoid 9b to drive the second solenoid 9b, and when the solenoid drive request signal SS2 is not input, The power supply to the second solenoid 9b is cut off. Thus, the microcomputer 1 can cut off the power supply to the solenoids 9a and 9b using the solenoid drive circuits 8a and 8b.

  The monitoring circuit 3 monitors the operation of the microcomputer 1. Specifically, signals are periodically exchanged between the monitoring circuit 3 and the microcomputer 1, and the monitoring circuit 3 detects an abnormality of the microcomputer 1 based on a signal acquired from the microcomputer 1. When an abnormality of the microcomputer 1 is detected, the monitoring circuit 3 outputs a prohibition signal PS to the output prohibition circuit 4.

  When the monitoring circuit 3 detects an abnormality of the microcomputer 1, the output prohibition circuit 4 blocks power supply by the solenoid drive circuits 8 a and 8 b and the relay circuit 6 regardless of the control by the microcomputer 1. That is, the output prohibition circuit 4 prohibits the output of each request signal (the relay drive request signal RS and the solenoid drive request signals SS1 and SS2) from the microcomputer 1 according to the prohibition signal PS. The output prohibition circuit 4 includes three AND circuits 21 to 23. Each of the AND circuits 21 to 23 has one of two input terminals connected to the microcomputer 1 and the other connected to the monitoring circuit 3. Each AND circuit 21 to 23 inverts and inputs the inhibition signal PS from the monitoring circuit 3. Therefore, when the prohibition signal PS is input from the monitoring circuit 3, the request signals from the microcomputer 1 are not output to the relay drive circuit 5 and the solenoid drive circuits 8a and 8b. That is, each request signal is output to the relay drive circuit 5 or the solenoid drive circuits 8a and 8b when the request signal is output from the microcomputer 1 and the prohibition signal PS is not output from the monitoring circuit 3.

  The voltage detection circuit 2 is connected to the power supply terminal of the relay circuit 6 and detects the magnitude of the solenoid power supply voltage BS. The voltage detection circuit 2 outputs a signal indicating the detected solenoid power supply voltage BS to the microcomputer 1.

  In the present embodiment, one end of the capacitor 7 is connected to the downstream side (power supply end) of the relay circuit 6. The other end of the capacitor 7 is grounded. A capacitor | condenser is an example of the electrical storage means to hold | maintain the voltage supplied from the relay circuit 6 more than predetermined voltage only for predetermined time. As will be described in detail later, when the capacitor 7 checks whether or not the power supply cut-off by the relay circuit 6 and the solenoid drive circuits 8a and 8b is normally performed, the capacitor 7 sets the solenoid power supply voltage BS (the cut-off is normal). Provided to reduce slowly (if done).

  A power supply circuit 10 for supplying power to the microcomputer 1 is connected to the microcomputer 1. The power supply circuit 10 is connected to the battery 14 via the diode 12. The power supply circuit 10 supplies a predetermined voltage (for example, 5 [V]) to the microcomputer 1 using the power from the battery 14. Although details will be described in the second embodiment, the power supply circuit 10 outputs a reset signal RE to the microcomputer 1 when the predetermined power cannot be supplied.

  In FIG. 1, a diode 12 is connected between a battery 14 and a power supply circuit 10. The diode 12 has an anode terminal connected to the battery 14 and a cathode terminal connected to the power supply circuit 10. Hereinafter, a power supply voltage (voltage on the cathode side of the diode 12) supplied from the battery 14 to the power supply circuit 10 is referred to as a voltage VM. One end of the capacitor 11 is connected to the cathode side of the diode 12. The other end of the capacitor 11 is grounded. A diode 13 is provided between the cathode side of the diode 12 and the power supply end of the relay circuit 6. The diode 13 has an anode terminal connected to the power supply terminal and a cathode terminal connected to the cathode side of the diode 12. The diodes 12 and 13 are provided so that any one of the voltages at the upstream and downstream terminals of the relay circuit 6 is supplied to the power supply circuit 10.

  In the configuration shown in FIG. 1, some components may be configured as one chip. For example, the monitoring circuit 3, the output inhibition circuit 4, the relay drive circuit 5, and each solenoid drive circuit 8a and 8b may be configured as one chip.

  With the configuration described above, the solenoid drive device controls the solenoids 9a and 9b when the microcomputer 1 outputs request signals to the relay drive circuit 5 and the solenoid drive circuits 8a and 8b. When the monitoring circuit 3 determines that the microcomputer 1 is abnormal, the prohibition signal PS is output from the monitoring circuit 3, whereby the power supply to the solenoids 9a and 9b is cut off. Specifically, power supply is cut off in relay circuit 6 and solenoid drive circuits 8a and 8b. Further, in the configuration shown in FIG. 1, the solenoid drive device is configured so that the interruption in the relay circuit 6 (hereinafter referred to as “relay interruption”) is normally performed, and the interruption in each solenoid drive circuit 8a and 8b. (Hereinafter referred to as “solenoid shutoff”) can be independently checked to see if they are normally performed. Hereinafter, with reference to FIGS. 2 to 4, an interruption check operation by the solenoid driving apparatus according to the first embodiment will be described.

  FIG. 2 is a flowchart showing a flow of a shut-off check operation performed by the microcomputer 1 of the solenoid drive device. The shut-off check operation shown in FIG. 2 may be executed at any timing. For example, it is executed at a timing immediately after the microcomputer is activated after the vehicle is turned on.

  In step S1, the microcomputer 1 first sets an abnormal state in a pseudo manner. That is, the microcomputer 1 intentionally transmits a signal different from the normal exchange with the monitoring circuit 3 to the monitoring circuit 3 to cause the monitoring circuit 3 to determine that the microcomputer 1 is abnormal. As a result, the monitoring circuit 3 instructs the relay drive circuit 5 and the solenoid drive circuits 8a and 8b to shut off, that is, outputs a prohibition signal PS to the output prohibition circuit 4. Following step S1, the process of step S2 is executed.

  In step S2, the microcomputer 1 gives an instruction to drive the solenoids 9a and 9b. That is, the microcomputer 1 outputs solenoid drive request signals SS1 and SS2 and a relay drive request signal RS. Even if each request signal is output from the microcomputer 1 in step S2, the request signal is not output from the output prohibition circuit 4 because the monitoring circuit 3 outputs the prohibition signal PS in step S1. As a result, the solenoid drive circuits 8a and 8b do not drive the solenoids 9a and 9b, that is, interrupt the power supply to the solenoids 9a and 9b. Further, the relay drive circuit 5 does not supply power to the relay circuit 6 (cuts off power supply). Following step S2, the process of step S3 is executed.

  In other embodiments, the order of the process of step S1 and the process of step S2 may be reversed. Further, the microcomputer 1 may output the relay drive request signal RS to the relay drive circuit 5 before step S1. According to this, since the power from the battery 14 is supplied to the capacitor 7 by the relay circuit 6, the relay circuit 6 and each solenoid drive circuit are detected in response to the abnormality of the microcomputer 1 being detected by the monitoring circuit 3 in step S1. When the power supply by 8a and 8b is cut off, the capacitor 7 can be reliably charged.

  In the processes of steps S3 to S6, a process of checking whether or not the solenoid shut-off is normal is executed. In this embodiment, whether or not the solenoid is shut off normally can be checked by monitoring the magnitude of the solenoid power supply voltage BS. Details will be described below.

  FIG. 3 is a diagram illustrating a time change of the solenoid power supply voltage BS when the relay cutoff and the solenoid cutoff are performed. FIG. 4 is a diagram showing a change over time in the solenoid power supply voltage BS when the relay is shut off and the solenoid is not shut off in either the first or second solenoid drive circuit 8a or 8b. is there. 3 and 4, the horizontal axis represents time [ms], and the vertical axis represents the magnitude [V] of the solenoid power supply voltage BS. In FIG. 3 and FIG. 4, the time when the interruption is performed is set to 0 [ms]. Note that the time-varying characteristics vary depending on the characteristics of the capacitor 7 and variations in characteristics due to temperature, but in FIGS. 3 and 4, in the case of the minimum value (min), a standard value (average value, etc.) Graphs are shown for (typ) and for the maximum value (max). 3 and 4, it is assumed that the capacitor 7 is in a charged state at the time t = 0 [ms].

  Here, the capacitor 7 is an electrostatic that can hold the voltage supplied from the relay circuit 6 at a voltage higher than the predetermined voltage for at least a predetermined time after the power supply from the relay circuit 6 is cut off. It can be said that it has capacity. Therefore, as shown in FIG. 3, when the relay cutoff and the solenoid cutoff are normally performed, the solenoid power supply voltage BS gradually decreases (slowly as compared with FIG. 4). On the other hand, as shown in FIG. 4, when the relay is normally shut off and at least one of the solenoid drive circuits 8a and 8b is not normally shut off, the capacitor 7 is charged. Since the electric power is supplied to at least one of the solenoids 9a and 9b, the solenoid power supply voltage BS decreases rapidly as compared with FIG. In the graphs of FIG. 3 and FIG. 4, the solenoid power supply voltage BS is 2 [V] or more for at least 150 [ms] when the solenoid is normally shut down even if the capacitor variation is taken into consideration. You can see that It can also be seen that when the solenoid is not normally shut off, the solenoid power supply voltage BS drops to 2 [V] or less within 30 [ms].

  As described above, “the capacitor 7 holds the voltage supplied from the relay circuit 6 at a voltage higher than the predetermined first voltage for at least a predetermined first time after the power supply from the relay circuit 6 is cut off. If it has “capacitance that can be performed”, it can be determined as follows whether or not the solenoid is normally shut off. That is, whether the solenoid is normally shut off is determined by whether the solenoid power supply voltage BS is the first time until the first time elapses after the shut-off instruction is given by the monitoring circuit 3 (after step S1 is executed). It can be determined by whether or not one voltage is maintained. The first time and the first voltage are set in advance according to the characteristics of the capacitor 7 (in other words, the characteristics of the capacitor 7 are set so that appropriate values can be set as the first time and the first voltage. Just select). For example, in the case of FIG. 3 and FIG. 4, the first time is set to 60 [ms] (for example, a value twice as large as 30 [ms]), and the first voltage is set to 2 [ V].

  Details of the solenoid cutoff check process (steps S3 to S6) will be described below. In step S <b> 3, the microcomputer 1 detects the solenoid power supply voltage BS by acquiring a signal from the voltage detection circuit 2. In subsequent step S4, the microcomputer 1 determines whether or not the solenoid power supply voltage BS detected in step S3 is equal to or lower than the first voltage. If the determination result of step S4 is affirmative, the process of step S5 is executed. On the other hand, when the determination result of step S4 is negative, the process of step S6 is executed.

  In step S <b> 5, the microcomputer 1 determines that the solenoid is not normally shut off (it is a shutoff abnormality). Specifically, the microcomputer 1 notifies the user that the solenoid shut-off is abnormal by stopping the brake control using the solenoid or notifying other ECUs that the solenoid shut-off is abnormal. Process. Following step S5, a process of step S7 described later is executed.

  On the other hand, in step S <b> 6, the microcomputer 1 determines whether or not the elapsed time after the monitoring circuit 3 instructs to shut off (after step S <b> 1 is executed) exceeds the first time. If the determination result of step S6 is affirmative, the process of step S7 described later is executed. In this case, since the process of step S5 is not executed, it is determined that the solenoid is shut off normally. On the other hand, when the determination result of step S6 is negative, the process of step S3 is executed again. Thereafter, until the determination result of step S4 is affirmative and it is determined that solenoid shut-off is abnormal, or until the determination result of step S5 becomes affirmative when the elapsed time exceeds the first time, step S3 to step S3. The process of S6 is repeatedly executed.

  As described above, in this embodiment, after the instruction to shut off the power supply (step S1), the determination process (step S4) for determining whether the solenoid power supply voltage BS is equal to or lower than the predetermined first voltage is a predetermined process. Until the first time elapses (Yes in step S6). If the solenoid power supply voltage BS becomes equal to or lower than the predetermined first voltage before the first time elapses, it is determined that the solenoid shut-off is abnormal (step S5), and the solenoid power supply voltage BS is set to the predetermined first voltage. If the first time has elapsed without becoming the following, it is determined that the solenoid is shut off normally. As described above, it can be easily determined whether or not the solenoid is normally shut off.

  In the processes of steps S7 to S10, a process of checking whether or not the relay interruption is normal is executed. Here, if the relay is not interrupted, the power is supplied from the relay circuit 6 to the power supply end, so that the solenoid power supply voltage BS does not decrease. That is, after step S1, if the solenoid power supply voltage BS has not decreased, it can be seen that the relay is not normally shut off. From the above, “the capacitor 7 has a capacitance at which the voltage held thereby becomes at least a predetermined second voltage or less when a predetermined second time has elapsed after the power supply from the relay circuit 6 is cut off. If it has ", it can be determined as follows whether the relay cutoff is normally performed or not. That is, whether or not the relay is normally shut off is determined by whether or not the solenoid power supply voltage BS has become equal to or lower than the second voltage before the second time elapses after the monitoring circuit 3 issues the cutoff instruction. Can be determined. As described above, whether or not the relay is interrupted normally can be checked by monitoring the magnitude of the solenoid power supply voltage BS as in the case of the solenoid drive circuits 8a and 8b.

  As described above, in the processes of steps S7 to S10, it is determined whether or not the solenoid power supply voltage BS has become equal to or lower than the second voltage after the second instruction has passed since the monitoring circuit 3 issued the cutoff instruction. Specifically, in step S7, the microcomputer 1 detects the solenoid power supply voltage BS by acquiring a signal from the voltage detection circuit 2 as in step S3. In subsequent step S8, the microcomputer 1 determines whether or not the solenoid power supply voltage BS detected in step S3 is equal to or lower than the second voltage. Here, the second voltage is normally set to a value higher than the first voltage, for example, set to 6.5 [V]. If the determination result of step S8 is affirmative, the process of step S11 described later is executed. On the other hand, when the determination result of step S8 is negative, the process of step S9 is executed.

  In step S <b> 9, the microcomputer 1 determines whether or not the elapsed time after the monitoring circuit 3 instructs to shut off (after step S <b> 1 is executed) exceeds the second time. Here, the second time is set to a value longer than the first time, for example, 2000 [ms]. If the determination result of step S9 is affirmative, the process of step S10 is executed. On the other hand, when the determination result of step S10 is negative, the process of step S7 is executed again. Thereafter, until the solenoid power supply voltage BS becomes equal to or lower than the second voltage and the determination result of step S8 becomes affirmative, or the determination result of step S10 becomes affirmative when the elapsed time exceeds the second time, step S7. The processes of S9 are repeatedly executed.

  In step S <b> 10, the microcomputer 1 determines that the relay has not been normally shut off (it is a shutoff abnormality). Specifically, as in step S5, the microcomputer 1 stops the brake control using the solenoid or notifies other ECUs that the relay is interrupted to indicate that the relay is interrupted abnormally. To notify the user. Following step S10, the process of step S11 is executed.

  As described above, in this embodiment, after the instruction to shut off the power supply (step S1), the determination process (step S8) for determining whether the solenoid power supply voltage BS is equal to or lower than the predetermined second voltage is a predetermined process. Until the second time elapses (Yes in step S9). If the solenoid power supply voltage BS does not become equal to or lower than the predetermined second voltage before the second time elapses, it is determined that the relay cutoff is abnormal (step S10), and the solenoid power supply voltage BS is set to the predetermined second voltage. When the voltage falls below the voltage, it is determined that the relay is cut off normally. As described above, it can be easily determined whether or not the relay is normally shut off.

  In step S11, the microcomputer 1 gives an instruction to stop driving the solenoids 9a and 9b. That is, the microcomputer 1 stops outputting the solenoid drive request signals SS1 and SS2 and the relay drive request signal RS. After step S11, the microcomputer 1 ends the shut-off check operation shown in FIG.

  As described above, in the present embodiment, by providing the capacitor 7 on the downstream side of the relay circuit 6, when the relay cutoff is abnormal, when the solenoid cutoff is abnormal, and both the relay cutoff and the solenoid cutoff are performed. In each case of normal, a difference was made in the change of the solenoid power supply voltage BS. Accordingly, it is possible to check whether or not the two types of blocking are normal, and the blocking check can be performed in detail. Further, in this embodiment, it is not necessary to provide a separate check circuit for checking two types of interruptions, and two types of interruptions can be checked with a simple configuration in which a capacitor 7 is provided.

In the first embodiment, the microcomputer 1 executes the solenoid cutoff check process (steps S3 to S6) first and the relay cutoff check process (steps S7 to S10) later. Here, in another embodiment, either the solenoid cutoff check process or the relay cutoff check process may be executed first. At this time, the second time is set shorter than the first time. Further, the microcomputer 1 may simultaneously execute a solenoid cutoff check process and a relay cutoff check process. Specifically, the microcomputer 1 sets the first time and the second time to the same time, and the solenoid power supply voltage at the time when the elapsed time after the monitoring circuit 3 instructs to shut down becomes the first time. It is determined which of the following (a) to (c) the size of the BS corresponds to.
(A) It is below the first voltage.
(B) greater than the first voltage and less than or equal to the second voltage.
(C) It is larger than the second voltage.
Then, it may be determined that (a) indicates that the solenoid is shut off abnormally, (b) that both the solenoid shut off and relay are shut off normally, and (c) that the relay is shut off abnormally. It should be noted that if the elapsed time is too long, the solenoid cutoff check will be inaccurate, and if the elapsed time is too short, the relay cutoff check will be inaccurate. Normally, as in the first embodiment, the solenoid cutoff check It is preferable that the block check process is executed first and the relay block check process is executed later. That is, it is preferable that the first time is set shorter than the second time.

(Second Embodiment)
Next, a solenoid driving apparatus according to the second embodiment of the present invention will be described. As in the first embodiment, it is conceivable that the solenoid drive device uses a vehicle battery as a power source. However, the vehicle battery supplies power to other devices mounted on the vehicle. When many devices require power, the power supplied to the battery may be temporarily reduced. When a semiconductor relay is used as the relay circuit 6, the voltage supplied to the relay circuit 6 temporarily decreases when the battery supply power decreases. Therefore, when the battery supply power decrease occurs during the above-described interruption check operation, The microcomputer 1 cannot perform the check accurately, and may make an erroneous determination. Specifically, when the voltage supplied to the relay circuit 6 decreases due to a decrease in the battery voltage, the solenoid power supply voltage BS decreases, so that the determination result in step S4 in the shut-off check operation is affirmative, (originally Even if the solenoid shut-off is normal, it is erroneously determined that the solenoid shut-off is abnormal. Therefore, in the second embodiment, in order to prevent erroneous determination of the microcomputer 1, the solenoid driving device resets the shut-off check operation when the supply power of the battery 14 is reduced. Details will be described below.

  The configuration of the solenoid drive device according to the second embodiment is the same as that shown in FIG. Here, in the second embodiment, if the voltage (hereinafter referred to as the microcomputer power supply voltage) VM supplied from the battery 14 to the power supply circuit 10 is 6 [V], the power supply circuit 10 supplies the microcomputer 1 with a predetermined value. It is possible to supply a voltage (for example, 5 [V]). When the power supply circuit 10 cannot supply a predetermined voltage (for example, 5 [V]) to the microcomputer 1 (that is, when the microcomputer power supply voltage VM is 6 [V] or less), the power supply circuit 10 A reset signal RE is output.

  FIG. 5 is a diagram illustrating a time change of the microcomputer power supply voltage VM when the battery voltage is set to 0 [V]. The horizontal axis of the graph in FIG. 5 is time [ms], and the vertical axis is the magnitude [V] of the microcomputer power supply voltage VM. In FIG. 5, the time when the battery voltage is set to 0 [V] is set to 0 [ms]. Note that the time-varying characteristics change due to variations in characteristics of the capacitor 11 and the diodes 12 and 13 and changes in characteristics due to temperature. In FIG. 5, in the case of the minimum value (min), a standard value (average The graph is shown for the case of (value etc.) (typ) and the case of the maximum value (max). As shown in FIG. 5, it is understood that when the battery voltage is set to 0 [V], the microcomputer power supply voltage VM gradually decreases, and becomes a predetermined voltage or less after a certain period of time. Therefore, when the battery voltage decreases, the power supply circuit 10 outputs the reset signal RE to the microcomputer 1 after a certain time has elapsed, and as a result, the microcomputer 1 is reset. In other words, if the power supply circuit 10 cannot supply a predetermined voltage to the microcomputer 1, it can be said that the microcomputer 1 resets the microcomputer 1 until a predetermined time elapses after the cutoff instruction is given. Although depending on the characteristics and temperature of the element such as the capacitor 11, in FIG. 5, the microcomputer power supply voltage VM becomes 6 [V] or less after 10 [ms] has elapsed since the battery voltage became 0 [V]. . Therefore, here, when 10 [ms] has elapsed since the battery voltage decreased, the battery power supply voltage VM decreases to 6 [V] or less, and the power supply circuit 10 outputs the reset signal RE to the microcomputer 1. 1 is reset.

  As described above, in the interruption check operation according to the second embodiment, an erroneous determination is made by utilizing the fact that the microcomputer 1 is reset when a predetermined time (10 [ms]) elapses after the battery voltage decreases. The microcomputer 1 is reset before being performed, so that the microcomputer 1 does not make an erroneous determination. FIG. 6 is a flowchart showing a flow of a shut-off check operation performed by the microcomputer 1 of the solenoid drive device according to the second embodiment. In FIG. 6, steps that perform the same processing as in FIG. 2 are assigned the same step numbers as in FIG.

  In the second embodiment, when the determination result of step S4 is affirmative, the process of step S21 is executed. In step S <b> 21, the microcomputer 1 determines whether or not the elapsed time after the monitoring circuit 3 issues the shut-off instruction has exceeded a predetermined third time. The third time only needs to be set longer than the predetermined time (10 [ms]). In the present embodiment, the third time is set to 20 [ms] with a margin for 10 [ms]. . If the determination result of step S21 is affirmative, the process of step S5 is executed. On the other hand, when the determination result of step S21 is negative, the process of step S3 is executed again.

  As described above, in the second embodiment, when the solenoid power supply voltage BS becomes equal to or lower than the first voltage (Yes in Step S4) and the elapsed time exceeds the third time (Yes in Step S21), the solenoid It is determined that the interruption is abnormal (step S5). That is, the microcomputer 1 repeats the processing loop of steps S3, S4 and S21 until the elapsed time exceeds the third time even if the solenoid power supply voltage BS becomes equal to or lower than the first voltage. Here, as described above, in the second embodiment, the microcomputer 1 is reset when a predetermined time shorter than the third time elapses after the battery voltage decreases. Therefore, when the battery voltage decreases, the microcomputer 1 is reset while the microcomputer 1 repeats the processing loop of steps S3, S4 and S21. In other words, in the second embodiment, the microcomputer 1 is reset before the determination of step S5 is performed, and the microcomputer 1 stops the shut-off check operation, so that it is not erroneously determined that the solenoid shut-off is abnormal. .

  As described above, according to the second embodiment, it is possible to prevent the microcomputer 1 from making an erroneous determination even when the battery voltage is lowered, and the solenoid drive device performs the shut-off check operation more accurately. It can be carried out. In addition, since there is a possibility that the supplied power of the battery is lowered in the time zone immediately after the ignition switch of the vehicle is turned on, the second embodiment is used when the interruption check operation is performed in this time zone. The processing in is particularly effective.

  As described above, the present invention can be used, for example, as a solenoid driving device mounted on a vehicle, for example, to check in detail whether the power supply to the solenoid is cut off in a simple configuration. Is possible.

The block diagram which shows the structure of the solenoid drive device which concerns on 1st Embodiment. The flowchart which shows the flow of the interruption | blocking check operation | movement which the microcomputer 1 of a solenoid drive device performs. The figure which shows the time change of the solenoid power supply voltage BS when the relay interruption | blocking and solenoid interruption | blocking are performed The figure which shows the time change of the solenoid power supply voltage BS when relay interruption | blocking is performed and solenoid interruption | blocking is not performed in either the 1st or 2nd solenoid drive circuit 8a or 8b. The figure which shows the time change of the microcomputer power supply voltage VM when a battery voltage is set to 0 [V]. The flowchart which shows the flow of the interruption | blocking check operation | movement which the microcomputer 1 of the solenoid drive device which concerns on 2nd Embodiment performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microcomputer 2 Voltage detection circuit 3 Monitoring circuit 4 Output prohibition circuit 5 Relay drive circuit 6 Relay circuit 7,11 Capacitor 8a, 8b Solenoid drive circuit 9a, 9b Solenoid 12, 13 Diode 14 Battery

Claims (7)

A solenoid drive circuit that drives the solenoid by supplying power to the solenoid;
A relay circuit for supplying power from a power source to the solenoid drive circuit;
Control means for controlling power supply by the solenoid drive circuit and the relay circuit;
A power storage means connected to a power supply end between the relay circuit and the solenoid drive circuit, and holding a voltage supplied from the relay circuit;
The control means is configured such that the voltage of the power supply terminal is equal to or lower than a predetermined first voltage after a predetermined first time elapses after a cutoff instruction for cutting off power supply by the solenoid drive circuit and the relay circuit is performed. It is determined that the interruption by the solenoid drive circuit is abnormal, at least as a condition, and the voltage of the power supply terminal is between the time when the interruption instruction is given and a predetermined second time elapses. A solenoid drive device that determines that the interruption by the relay circuit is abnormal at least on the condition that the voltage is maintained at a value larger than a predetermined second voltage.   The solenoid driving device according to claim 1, wherein the first time is set shorter than the second time.   The power storage means can hold the voltage supplied from the relay circuit at a voltage higher than the first voltage for at least the first time after the power supply from the relay circuit is cut off. The solenoid drive device according to claim 1, having a capacitance.   The power storage means has a capacitance at which a voltage held thereby becomes at least equal to or lower than the second voltage when the second time elapses after the power supply from the relay circuit is cut off. 2. The solenoid drive device according to 1. The control means includes
Drive control means for controlling the drive of the solenoid drive circuit and the relay circuit;
Monitoring means for monitoring an abnormality of the drive control means;
A shut-off means for giving a shut-off instruction for shutting off the power supply by the solenoid drive circuit and the relay circuit, regardless of the control by the drive control means, when an abnormality of the drive control means is detected by the monitoring means; The solenoid drive device according to claim 1. The solenoid driving device is mounted on a vehicle and uses a vehicle battery as the power source.
The power supply circuit further includes a power supply circuit configured to supply predetermined power to the control unit by power from the battery and reset the processing in the control unit when the predetermined power cannot be supplied due to insufficient power supply from the battery. ,
The control means is configured to perform a predetermined first time after a predetermined third time has elapsed since the cutoff instruction is issued and after a cutoff instruction for cutting off power supply by the solenoid drive circuit and the relay circuit is issued. 2. The solenoid drive according to claim 1, wherein the interruption by the solenoid drive circuit is determined to be abnormal on the condition that the voltage of the power supply terminal becomes equal to or lower than a predetermined first voltage until the time elapses. apparatus.   The solenoid drive device according to claim 6, wherein when the predetermined power cannot be supplied, the power supply circuit resets the processing in the control means until the third time elapses after the cutoff instruction is given.

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