JP2006196251A - Interlock circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly determine the presence/absence of an interlock operation by considering circuit trouble such as disconnection. <P>SOLUTION: An interlock switch (ILK switch) 10 short-circuits a potential detection terminal DT to GND in interlock non-operation and connects the potential detection terminal DT to GND in interlock operation by interposing a resistor R2. An ECU 20 detects the interlock non-operation, the interlock operation or the disconnection of an interlock circuit based on the potential of the potential detection terminal DT. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an interlock circuit that cuts off power supply from a high-voltage battery to a load.

  Conventionally, in an electric vehicle equipped with a high-voltage battery, an interlock function (shut-off function) that electrically disconnects the high-voltage battery and the load such as an inverter to ensure safety during battery charging, inspection, and maintenance work Are known.

  The interlock function operates in response to an interlock operation by the user. In order to realize this, an interlock circuit including a switch that switches based on an interlock operation is known. For example, a circuit configuration in which the potential when the interlock operation is not performed and the potential when the interlock operation is performed are set to different potentials, and the ECU determines whether or not the interlock operation is performed based on this potential Is possible.

  However, in a circuit configuration in which the presence or absence of an interlock operation is determined based on only two types of potentials, for example, if one of the two types of potentials is switched due to disconnection in the circuit, the presence or absence of an interlock operation is determined. There is a risk of detection by mistake.

  Incidentally, Patent Document 1 discloses a detection device that provides an impedance element in parallel with a switching portion and detects when the switching portion is on, off, and disconnected. Patent Document 2 discloses an emergency call system terminal that identifies four states of opening, pressing, opening, and shorting of a switch. Patent Document 3 discloses a technique for detecting a disconnection or a short circuit in addition to an open / closed state by connecting two terminals of a microcomputer with different resistances according to the opening / closing of a switch.

Japanese Patent Laid-Open No. 5-28872 JP 2001-101555 A Japanese Patent Laid-Open No. 11-237427

  From the background described above, a circuit configuration for identifying disconnection of a circuit in addition to the presence or absence of an interlock operation is also desired in the interlock circuit.

  Therefore, an object of the present invention is to provide an interlock circuit capable of appropriately detecting the presence or absence of an interlock operation in consideration of a circuit failure such as disconnection.

  In order to achieve the above object, an interlock circuit according to a preferred aspect of the present invention is a vehicle interlock circuit having an interlock function for cutting off power supply from a high voltage battery to a load. An ECU having a first resistor connected between the potential detection terminal and the predetermined potential portion, and an interlock switch provided between the potential detection terminal and the ground potential portion. The switch short-circuits the potential detection terminal and the ground potential portion when the interlock is not activated, and connects the potential detection terminal and the ground potential portion with a second resistor when the interlock is activated. Based on the potential of the potential detection terminal, the interlock non-operation, the interlock operation, or the disconnection of the interlock circuit is detected. To.

  According to the present invention, there is provided an interlock circuit for detecting interlock non-operation, interlock operation, or disconnection of the interlock circuit.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a preferred embodiment of an interlock circuit according to the present invention, and FIG. 1 shows its circuit configuration.

  The interlock circuit of this embodiment is mounted on an electric vehicle that uses a motor as a power source, a hybrid vehicle that uses an engine and a motor as power sources, and power from a high-voltage battery to a load (such as an inverter or a motor). An interlock function that cuts off the supply is realized. When the interlock function is activated, the operator performs an interlock operation using, for example, a lever housed in a trunk behind the vehicle or an engine room in front of the vehicle.

  The interlock switch (ILK switch) 10 performs a switching operation in accordance with the operator's interlock operation. In a state where the interlock operation is not performed (interlock is not activated), the terminal ST1 is selected by the ILK switch 10. For example, the terminal ST1 is selected in a situation where the motor is driven to drive the vehicle.

  When the interlock operation is performed (interlock operation), the terminal ST2 is selected by the ILK switch 10. For example, the terminal ST2 is selected when checking the inverter. The selection result of the terminal ST1 or the terminal ST2 by the ILK switch 10 is reflected in the potential of the potential detection terminal DT.

  ECU20 judges the presence or absence of interlock operation based on the electric potential of electric potential detection terminal DT. The potential detection terminal DT is connected to the power supply terminal Vcc via the resistor R1 inside the ECU 20. That is, the resistor R1 functions as a pull-up resistor. The potential detection terminal DT is connected to the ILK switch 10 outside the ECU 20.

  As described above, when the interlock is not activated, the terminal ST1 is selected by the ILK switch 10. For this reason, when the interlock is not operated, the potential detection terminal DT is short-circuited to GND (ground), and the potential of the potential detection terminal DT becomes 0 volts.

  On the other hand, during the interlock operation, the terminal ST2 is selected by the ILK switch 10. For this reason, during the interlock operation, the potential detection terminal DT is connected to GND via the resistor R2. Therefore, the potential of the potential detection terminal DT during the interlock operation is R2 × Vcc / (R1 + R2) volts.

  The ECU 20 determines whether the interlock is not activated or the interlock is activated from the potential of the potential detection terminal DT. The potential of the potential detection terminal DT is transmitted to a control unit (not shown) in the ECU 20 via the resistor Rb and the buffer 22, and the control unit makes a determination based on the potential. That is, if the potential of the potential detection terminal DT is 0 volts, it is determined that the interlock is not activated, and if the potential of the potential detection terminal DT is R2 × Vcc / (R1 + R2) volts, it is determined that the interlock is activated. If ECU20 judges that it is an interlock operation | movement, it will operate an interlock function by interrupting | blocking the relay which exists on the electricity supply circuit from a high voltage battery to load.

  In the present embodiment, the ECU 20 can detect a disconnection in the interlock circuit in addition to the determination of the interlock non-operation or the interlock operation. For example, when the portion at position A shown in FIG. 1 is disconnected, the outside of the ECU 20 of the potential detection terminal DT is opened, and the potential of the potential detection terminal DT rises to Vcc volts by the pull-up action of the resistor R1.

  Therefore, the ECU 20 can identify three types of states according to the potential of the potential detection terminal DT. That is, if the potential of the potential detection terminal DT is 0 volts, it is determined that the interlock is not activated, and if the potential of the potential detection terminal DT is R2 × Vcc / (R1 + R2) volts, it is determined that the interlock is activated. If the potential of the potential detection terminal DT is Vcc volts, it is determined that the circuit is disconnected. When it is determined that the circuit is disconnected, the ECU 20 turns on a warning lamp indicating that the circuit is disconnected, for example, on a front panel of a vehicle interior. Of course, a warning light indicating interlock operation or non-operation may be turned on.

  As mentioned above, although preferred embodiment of this invention was described, embodiment mentioned above is only a mere illustration in all the points, and does not limit the scope of the present invention. For example, FIG. 1 shows a configuration in which the terminal ST1 and the terminal ST2 are selected as the ILK switch 10. However, instead of selecting the terminals ST1 and ST2, the potential detection terminals DT and GND are short-circuited when the interlock is not operated, and the potential detection terminals DT and GND are connected via the resistor R2 when the interlock is operated. Other configurations may be employed.

It is a figure which shows the interlock circuit based on this invention.

Explanation of symbols

  10 ILK switches, 20 ECUs.

Claims (1)

In an interlock circuit of a vehicle having an interlock function that cuts off power supply from a high voltage battery to a load,
An ECU having a potential detection terminal;
A first resistor connected between the potential detection terminal and a predetermined potential portion;
An interlock switch provided between the potential detection terminal and the ground potential portion;
Have
The interlock switch short-circuits the potential detection terminal and the ground potential portion when the interlock is not activated, and connects the potential detection terminal and the ground potential portion with a second resistor interposed when the interlock is activated.
The ECU detects interlock non-operation, interlock operation, or disconnection of the interlock circuit based on the potential of the potential detection terminal.
An interlock circuit characterized by that.

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