JP2008002835A - Disconnection detector for connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exactly detect disconnection of a connector terminal, and to contribute to avoiding a trouble in a connector caused by the disconnection. <P>SOLUTION: A monitoring circuit 13 monitors a potential of a transmission line flowing with a driving current supplied a load 3 via the plurality of parallel connector terminals 21, 22, and a CPU 11 determines the presence of the disconnection in at least one of the connector terminals 21, 22, based on a monitor signal obtained based on the potential monitored by the monitoring circuit 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a disconnection detecting device for a connector that transmits one signal current through a plurality of connector terminals in parallel.

  Conventionally, as a technique for diagnosing an abnormality (disconnection / short circuit) of an external circuit connected via a connector, for example, those described in the following documents are known (see Patent Document 1). In the technique described in this document 1, four solenoid valves and drive elements included in a control unit that drives and controls these solenoid valves are connected via a harness, and detected by a voltage detection circuit connected to the harness. Based on the detected voltage, it is detected that an abnormal leakage current is generated in the solenoid valve.

  In such a monitoring device, the solenoid valve and the drive element connected in a one-to-one correspondence are each one solenoid valve corresponding to one drive element of the control unit via one connector terminal of one harness. Was connected to. That is, the drive current is controlled to be supplied to one solenoid via one connector terminal.

  On the other hand, in recent years, the miniaturization and integration of electronic components have led to the miniaturization of connectors. With the miniaturization of connectors, the diameter of connector terminals has become smaller, and the allowable current value that can be passed to one connector terminal has also decreased. Yes.

When trying to input / output a large current using such a connector, a plurality of connector terminals are assigned to one signal current, and one signal current is input / output via the plurality of connector terminals. . For example, when a signal current of about 5 A is input / output via a connector whose allowable current value of one connector terminal is about 3 A, two connector terminals are assigned to this signal current, and the two connector terminals are connected in parallel. A signal current of 5 A was input / output.
JP-A-6-87429

  However, when one signal current is input through a plurality of parallel connector terminals as described above, when a connector terminal that cannot flow current occurs due to an internal connection failure or disconnection of the plurality of connector terminals. Could not detect these defects. For this reason, the signal current flows through the remaining normal connector terminals, and there is a possibility that a current exceeding the allowable current value flows through the normal connector terminals. For example, as in the previous case, when two connector terminals with an allowable current value of about 3A are used in parallel and a signal current of about 5A is input / output, if one connector terminal is disconnected, the other connector terminal is connected. A current of about 5 A exceeding the allowable current value flows. If a current exceeding the allowable current value flows through the connector terminal, the connector terminal may generate heat and burnout may be broken, or the surroundings of the heated connector terminal may be adversely affected by heat generation, for example, the connector itself may be broken.

  Therefore, the present invention has been made in view of the above, and an object of the present invention is to detect a disconnection of a connector terminal accurately and to contribute to avoiding a failure of the connector due to the disconnection. Is to provide.

  In order to achieve the above object, the invention according to claim 1 is a connector disconnection detecting device for transmitting one signal through a plurality of parallel connector terminals, and is connected to each connector terminal of the plurality of parallel connector terminals. Monitoring means for independently monitoring the potential of each transmission path through which the signal is transmitted, and at least one connector terminal of the plurality of parallel connector terminals based on the monitoring result of the monitoring means. And determining means for determining whether or not the wire is disconnected.

  According to the first aspect of the present invention, disconnection of at least one connector terminal among a plurality of parallel connector terminals transmitting one signal can be detected easily and reliably.

  According to a second aspect of the present invention, in the connector disconnection detecting device according to the first aspect, the determination means is disconnected when a monitoring result indicating the disconnection is obtained by the monitoring means continuously for a predetermined time. It is characterized by determining that this has occurred.

  According to the second aspect of the present invention, it is possible to eliminate the influence of disturbance factors such as noise in the determination of disconnection, and it is possible to accurately detect disconnection by preventing erroneous detection of disconnection.

  According to a third aspect of the present invention, in the connector disconnection detecting device according to the first aspect, the determination means is disconnected when a monitoring result indicating disconnection is obtained by the monitoring means continuously for a predetermined number of times. It is characterized by determining that this has occurred.

  According to the third aspect of the present invention, it is possible to eliminate the influence of disturbance factors such as noise in the determination of disconnection, and it is possible to accurately detect disconnection by preventing erroneous detection of disconnection.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best embodiment for carrying out the present invention will be described below with reference to the drawings.

  1 is a diagram illustrating a configuration of a connector disconnection detection apparatus according to a first embodiment of the present invention. The apparatus of Example 1 shown in FIG. 1 shows a configuration when applied to a drive device that drives a load. The drive device 1 including a connector disconnection detection device is connected to a load 3 via a connector 2. ing.

  The drive device 1 includes a CPU 11 that functions as a control center for driving the load 3, a drive circuit (IPD) 12 that supplies a drive signal to the load 3, and a monitor circuit 13 that monitors disconnection of the connector 2. Constitutes a connector disconnection detection device.

  The connector 2 includes two connector terminals 21 and 22 and is configured to be integrated with the driving device 1 or provided separately from the driving device 1 to connect the driving device 1 and the load 3. is doing.

  The CPU 11 included in the drive device 1 includes computer resources such as an input / output device, a central processing unit, and a storage device included in a general-purpose microcomputer, and is based on a control program prepared in advance according to a control target. The computer resources cooperate to output a drive signal to the drive circuit 12 to drive and control the load 3 to be controlled. The CPU 11 inputs a monitor signal supplied from the monitor circuit 13, determines disconnection of the connector terminals 21 and 22 based on the monitor signal, and detects disconnection of at least one of the connector terminals 21 and 22. Stops supplying the drive current to the load 3 and performs a fail-safe operation.

  The drive circuit 12 receives, for example, a pulse signal drive signal supplied from the CPU 11 and controls the drive of the load 3 by controlling the drive current supplied to the load 3 by, for example, PWM control based on this drive signal. .

  The monitor circuit 13 includes a PNP bipolar transistor T1, resistors R1 to R5, and diodes D1 and D2. The transistor T1 has a base terminal connected to a connection point between the resistor R3 and the resistor R4 and one end of the resistor R5, an emitter terminal connected to a high-level power supply (Vign), and a collector terminal connected to one end of the resistor R1 and the resistor R2. It is connected to the.

  The resistor R1 has one end connected to the collector terminal of the transistor T1 and one end of the resistor R2, and the other end connected to an input terminal for inputting a monitor signal of the CPU 11. The resistor R2 has one end connected to the collector terminal of the transistor T1 and one end of the resistor R1, and the other end grounded. The resistor R3 has one end connected to the high-level power supply (Vign) and the other end connected to the base terminal of the transistor T1 and one ends of the resistors R4 and R5. The resistor R4 has one end connected to the base terminal of the transistor T1 and one ends of the resistors R3 and R5, and the other end connected to the connector terminal 22 and the cathode terminal of the diode D2. The resistor R5 has one end connected to the base terminal of the transistor T1 and one ends of the resistors R3 and R4, and the other end connected to the connector terminal 21 and the cathode terminal of the diode D1.

  The diode D1 has an anode terminal connected to an output terminal that supplies current to the load 3 of the drive circuit 12 and an anode terminal of the diode D2, and a cathode terminal connected to the connector terminal 21 and one end of the resistor R5. The diode D2 has an anode terminal connected to an output terminal that supplies current to the load 3 of the drive circuit 12 and an anode terminal of the diode D1, and a cathode terminal connected to the connector terminal 22 and one end of the resistor R4.

  Here, the resistance values of the resistors R3, R4, and R5 are set so that the base-emitter potential at which the transistor T1 is turned off when the potentials of the connector terminals 21 and 22 are at a high level is obtained (hereinafter referred to as the resistance values). This state is called case 1). Further, when the potentials of both the connector terminals 21 and 22 become low level and current flows from the high-level power supply (Vign) to the resistors R4 and R5 in the monitor circuit 13, the base potential of the transistor T1 is the same for both the connector terminals 21 and 22. The resistance values of the resistors R3, R4, and R5 are set such that the base-emitter potential of the transistor T1 when the base potential is lowered turns on the transistor T1. (This state is hereinafter referred to as case 2). Further, when the potential of one of the connector terminals 21 and 22 becomes low level and the other potential becomes high level, current flows from the high level power supply (Vign) to either the resistor R4 or the resistor R5 in the monitor circuit 13. At this time, the base potential of the transistor T1 is higher than when both the connector terminals 21 and 22 are at the low level. When the base potential is increased, the base-emitter potential at which the transistor T1 is turned off. The resistance values of the resistors R3, R4 and R5 are set so as to obtain (hereinafter, this state is referred to as case 3).

  In such a configuration, disconnection of the connector terminals 21 and 22 is determined according to the procedure shown in the flowchart of FIG. Referring to FIG. 2, for example, when a drive signal having a signal waveform as shown in (a) of the timing chart of FIG. 3 is given from the CPU 11 to the drive circuit 12, both connector terminals connected in parallel based on this drive signal are referred to. The drive current is controlled to be supplied from the drive circuit 12 to the load 3 through 21 and 22. At this time, the drive current supplied to the load 3 is controlled by PWM control and variably controlled by changing the duty ratio of the drive signal (step S21).

  In this way, the CPU 11 determines whether or not the monitor signal supplied from the monitor circuit 13 to the CPU 11 is abnormal while the drive current is supplied to the load 3 (step S22).

  In a normal state in which the drive current is supplied to the load 3 via both the connector terminals 21 and 22 without disconnecting the connector terminals 21 and 22, the potential of the connector terminals 21 and 22 corresponds to the potential change of the drive signal. Change. In such a state, if the potentials of both the connector terminals 21 and 22 are at a high level, the case 1 described above occurs, and the base-emitter potential of the transistor T1 is the potential that turns on the transistor T1. The transistor T1 is turned off. As a result, the collector potential of the transistor T1 becomes low level, and the monitor signal becomes low level.

  On the other hand, when the potentials of both the connector terminals 21 and 22 are at the low level, the case 2 described above occurs, and the base of the transistor T1 is compared with the case where the potentials of both the connector terminals 21 and 22 are at the high level. The emitter-to-emitter potential is lowered to a potential for turning on the transistor T1, and the transistor T1 is turned on. Thereby, the collector potential of the transistor T1 becomes a high level according to the setting of the resistance value of the resistor R2, and the monitor signal becomes a high level.

  Therefore, when both the connector terminals 21 and 22 are normal and not disconnected, the monitor signal has a signal waveform obtained by inverting the drive signal as shown in FIG. On the other hand, if the monitor signal does not have a signal waveform as shown in FIG. 3B, then a disconnection failure is determined (step S23).

  When one of the connector terminals 21 and 22 is disconnected, for example, when the connector terminal 21 is disconnected and the connector terminal 22 is normal, when the drive signal goes low, the high-level power supply (Vign ) Current flows through the resistor R4, but no current flows through the resistor R5 due to the disconnection of the connector terminal 21. As a result, the base potential of the transistor T1 is higher than when both the connector terminals 21 and 22 are normal and current flows through both the resistors R4 and R5, and this is the case of the case 3 described above. Therefore, the base-emitter potential for turning on the transistor T1 cannot be obtained, and the transistor T1 is turned off. Thereby, the collector potential of the transistor T1 becomes low level regardless of the change of the drive signal, the monitor signal becomes low level, and it is determined that the monitor signal is abnormal.

  Then, as shown in FIG. 3C, it is determined whether or not the monitor signal has continued such an abnormal state for a predetermined time (step S24). As a result of the determination, if the monitor signal is abnormal even after a predetermined time has elapsed, it is determined that the connector terminal 21 is broken. Thereafter, the output of the drive signal from the CPU 11 is stopped, the supply of the drive current to the load 3 is stopped, and the fail safe operation is performed (step S25). On the other hand, if the monitor signal returns to a normal signal waveform as shown in FIG. 3B before a predetermined time elapses, it is determined that the connector terminal 21 is not disconnected, and the load 3 remains unchanged. Continue to supply drive current.

  Even when the connector terminal 22 is broken and the connector terminal 21 is normal, the disconnection is determined in the same manner as described above.

  In this way, the disconnection of at least one connector terminal 21, 22 can be detected in the connector 2 that supplies the drive current to the load 3 via the plurality of parallel connector terminals 21, 22. In addition, the disconnection detection can be performed by providing the monitor circuit 13 having a relatively simple configuration and being easily integrated into an IC.

  In addition, by continuously observing the monitor signal for a predetermined time when the monitor signal is abnormal, it is possible to eliminate the influence of disturbance factors such as noise in the determination of disconnection failure, and to prevent erroneous detection of disconnection failure. Disconnection failure can be detected. Note that the predetermined time is determined and set, for example, by an experiment as a time that can eliminate the influence of disturbance factors such as noise on the monitor signal.

  Furthermore, when disconnection of the connector terminals 21 and 22 is detected, the supply of drive current to the load 3 is stopped to prevent a current exceeding the allowable value from flowing through the normal connector terminals 21 and 22. This makes it possible to avoid adverse effects on the surroundings due to burnout and heat generation of the connector 2.

  Next, a second embodiment of the present invention will be described. In the first embodiment, when it is determined that the connector terminals 21 and 22 are disconnected when the abnormality of the monitor signal continues for a predetermined time, the feature of the second embodiment is that the CPU 11 The monitor signal is periodically observed so that the change can be recognized in response to the change in the potential of the monitor signal, and it is determined that the connector terminals 21 and 22 are disconnected when the monitor signal abnormality continues for a predetermined number of times. The rest is the same as in the first embodiment.

  That is, disconnection determination processing is performed according to the procedure shown in the flowchart of FIG. 4, and steps S41, S42, and S43 shown in FIG. 4 are the same as steps S21, S22, and S23 shown in FIG. Operation is performed. Then, when the CPU 11 periodically monitors the monitor signal, as shown in the timing chart of FIG. 5C, when the monitor signal in the low level state is continuously observed a predetermined number of times. Is determined that at least one of the connector terminals 21 and 22 has a disconnection failure, and otherwise, it is determined that there is no disconnection failure (step S44). When a disconnection failure is detected, the same operation as step S25 shown in FIG. 2 of the first embodiment is performed (step S45).

  As described above, in the second embodiment, in the disconnection failure determination process, the presence or absence of a disconnection failure is determined based on the number of times the abnormal state of the monitor signal is observed. It becomes possible to eliminate the influence of the factor, prevent erroneous detection of disconnection failure, and accurately detect disconnection failure. Note that the predetermined number of times is determined and set, for example, by an experiment as the number of times that the influence of disturbance factors such as noise on the monitor signal can be eliminated.

  The present invention is not limited to the drive device for driving a load described in the first and second embodiments as long as it is a device that inputs and outputs a signal current via a plurality of parallel connector terminals. The above-described effects can be obtained by applying the present invention to any configuration that satisfies the above conditions. Further, the number of connector terminals is not limited to two, and even if the number of connector terminals is more than that, it can be easily implemented by expanding and developing the monitor circuit 13 shown in the first and second embodiments.

  Further, technical ideas other than the claims that can be grasped from the above-described embodiments will be described below together with effects.

(A) In the connector disconnection detection device according to any one of claims 1, 2, and 3,
A connector disconnection detection device comprising: a stop unit that stops transmission of the signal when the determination unit determines that at least one of the connector terminals is disconnected.

  According to the configuration described in the above item (A), it is possible to prevent adverse effects on the surroundings due to burnout and heat generation of the connector.

It is a figure which shows the structure of the disconnection detection apparatus of the connector which concerns on Example 1 of this invention. It is a flowchart which shows the determination procedure of the disconnection detection which concerns on Example 1 of this invention. It is a timing chart which shows the change of the monitor signal concerning Example 1 of the present invention. It is a flowchart which shows the determination procedure of the disconnection detection which concerns on Example 2 of this invention. It is a timing chart which shows the change of the monitor signal concerning Example 2 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Drive device 2 ... Connector 3 ... Load 11 ... CPU
DESCRIPTION OF SYMBOLS 12 ... Drive circuit 13 ... Monitor circuit 21, 22 ... Connector terminal D1, D2 ... Diode R1-R5 ... Resistance T1 ... Transistor

Claims (3)

In a disconnection detection device for a connector that transmits one signal via a plurality of parallel connector terminals,
Monitor means for independently and independently monitoring the potential of each transmission path connected to each connector terminal of the plurality of connector terminals in parallel and transmitting the signal,
A connector disconnection detection device comprising: a determination unit that determines whether at least one connector terminal of the plurality of parallel connector terminals is disconnected based on a monitoring result of the monitoring unit. 2. The connector according to claim 1, wherein the determination unit determines that a disconnection has occurred when a monitoring result indicating a disconnection is obtained by the monitoring unit continuously for a predetermined time. Disconnection detection device. 2. The connector according to claim 1, wherein the determination unit determines that a disconnection has occurred when a monitoring result indicating a disconnection is obtained by the monitoring unit continuously for a predetermined number of times. Disconnection detection device.

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