JP2007203929A - Dark current measuring device for vehicle, and power control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent battery exhaustion by precisely measuring a current flowing to an electric load under a stand-by condition at low costs, and suspending power supply when an abnormal action of the electric load is detected. <P>SOLUTION: This device comprises a relay interposed in a circuit for connecting a battery and a load, a current measuring circuit connected in parallel to the relay and connecting a current sensor for measuring a current and a semiconductor switch in series, and a control unit connected with the relay, the semiconductor switch and the current sensor. The control unit controls opening/closing of the relay and the semiconductor switch. When load starting signals are received, the relay is turned on, and the semiconductor switch is turned off. Meanwhile, when load stand-by signals (sleep signals) are received, the relay is turned off, and the semiconductor switch is turned on, so as to conduct a dark current to the current sensor and control power supply to the load according to values detected by the current sensor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle dark current measurement device and a vehicle dark current control device that controls power supply to a load according to the dark current measured by the measurement device. Even when the start-up current is flowing, the connection between the malfunctioning ECU and the battery is cut off to prevent the battery from being over-discharged (so-called battery running out) and the supply of dark current is cut off. To do.

Conventionally, since various electric loads (ECU: Electronic Control Unit, actuator, etc.) are operated using electric power charged in a battery in an automobile, it is important to suppress the electric power consumption of the battery as much as possible.
When the electric load is in the activated state, the load current is large, and when the electric load is in the standby state, the load current (that is, the standby current) is small. Therefore, the power consumption of the electric load varies greatly between the activated state and the standby state. Therefore, in a state where the ignition key is turned off or in a standby state, a desired control signal is given so that a part of the electric load is in a standby state, power supplied to the electric load is reduced, or power supply is performed. It is considered to reduce the power consumption by interrupting.

  For example, in Japanese Patent Laid-Open No. 2000-50513 (Patent Document 1), the standby current is zero by interrupting the power supply to the electric load after a lapse of a fixed time measured by a timer from when the ignition key is switched from on to off. The battery consumption is prevented by suppressing power consumption.

  However, even if a control signal is given to put the electric load in the standby state, the electric load may not enter the standby state, or an abnormal operation may be performed in which the electric load is activated again even once in the standby state. In the system of Patent Document 1, power supply to the electric load is interrupted after a predetermined time is measured by the timer. Therefore, the power supply cannot be interrupted until the timer is activated, and the electric load consumes power. Will cause the battery to run out.

Japanese Patent Application Laid-Open No. 2002-209330 (Patent Document 2) measures the value of a current flowing through an electric load and interrupts the power supply when an overcurrent flows to prevent the battery from running out. In the system of Patent Document 2, since the power supply is interrupted according to the result of the current value without using a timer, the time until the power supply is interrupted can be set shorter than that of the system of Patent Document 1.
However, the current flowing through the electric load varies greatly, for example, from 5 A to 10 mA when the electric load is in the start state and in the standby state, and a high-performance ammeter is required to measure the current. .

JP 2000-50513 A JP 2002-209330 A

The present invention has been made in view of the above problems, and a first object of the present invention is to provide a vehicle dark current measuring device that accurately measures a current flowing through an electric load in a standby state at low cost.
A second object of the present invention is to provide a vehicle power supply control device that detects an abnormal operation of an electric load using the vehicle dark current measuring device, interrupts the power supply when the abnormal operation is detected, and prevents the battery from running out. As an issue.

In order to solve the above problems, as a first invention,
A relay interposed in a circuit connecting the battery and the load;
A current measurement circuit connected in parallel with the relay, in which a current sensor for current measurement and a semiconductor switch are connected in series;
A control unit connected to the relay, the semiconductor switch and the current sensor;
The control unit controls opening and closing of the relay and the semiconductor switch, and turns on the relay when receiving a load start signal and turns off the semiconductor switch, and turns off the semiconductor switch while receiving the load standby signal (sleep signal). And a dark current measuring device for a vehicle that enables the dark current to flow to the current sensor by turning on the semiconductor switch.

  According to the present invention, when the control unit receives the load activation signal, the relay is turned on and the semiconductor relay is turned off, so that the current flows through the relay. For this reason, the current sensor does not measure the current when the load is in the activated state, but measures the current (dark current) in the standby state of the load. Since the value of the dark current is smaller than the value of the current flowing through the load in the start-up state, the measurement range of the current sensor can be made narrower than measuring the current flowing through the relay without using the current measurement circuit.

  Preferably, the control unit is configured to turn on the semiconductor switch before turning off the relay and to turn off the semiconductor switch after turning on the relay.

  When switching on and off of the relay and the semiconductor switch, both the relay and the semiconductor switch are turned on for a certain period of time, so that the load can be prevented from being completely cut off from the battery.

  Further, as a second invention, based on the current value detected by the dark current measuring device of the first invention, the circuit opening / closing means connected to the load is connected to or disconnected from the battery, and the power is supplied to or interrupted from the load. A vehicle power supply control device is provided.

  According to the present invention, the dark current of the load is measured using the dark current measuring device, and the abnormal operation is detected, for example, when the load is in a start-up state due to a malfunction even though it receives a standby command, When the load is performing an abnormal operation, the power supply control device can interrupt power supply and prevent the battery from running out.

As described above, according to the dark current measuring apparatus for a vehicle of the first aspect of the invention, since the current (dark current) in the standby state of the load is measured, the current sensor of the current sensor is measured rather than the current flowing through the relay. The measurement range can be narrowed. Therefore, the accuracy of measurement can be improved and the cost can be reduced.
In addition, the control unit is configured to turn on both the relay and the semiconductor switch for a certain period of time when switching the relay and the semiconductor switch on and off, thus preventing the load from being completely disconnected from the battery. it can.

  Furthermore, according to the vehicle power supply control device of the second aspect of the invention, the dark current of the load is measured using the dark current measuring device, and the load is in the activated state due to malfunction or the like even though the load receives a standby command. In such a case, the vehicle power supply control device can interrupt power supply and prevent the battery from running out when the load is performing an abnormal operation.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing a configuration of a vehicle dark current measuring apparatus 10 according to the present invention. In FIG. 1, the vehicle dark current measuring device 10 has a configuration in which one is connected to a battery 1 and the other is connected to an ECU 2 that is an electric load.

The vehicle dark current measuring apparatus 10 includes a relay 11, a current measuring circuit 12, and a control unit 15.
The relay 11 is interposed between the battery 1 and the ECU 2. The relay 11 receives a signal from the control unit 15 and connects / disconnects the ECU 2 to / from the battery 1. The relay 11 only needs to constitute a circuit opening / closing means such as a semiconductor switch, but is preferably an electromagnetic relay such as a relay and a latch relay that has a state holding function and can flow a larger current than the semiconductor relay.
The current measurement circuit 12 includes a current sensor 13 and a semiconductor switch 14, which are connected in series. The relay 11 is connected in parallel.
The current sensor 13 measures the dark current of the ECU 2 and sends the measurement result to the control unit 15.
The semiconductor switch 14 is connected to the current sensor in series, and is a protective switch that prevents an overcurrent exceeding the measurement range of the current sensor 13 from flowing into the current sensor 13. The semiconductor switch 14 is advantageous in that it can be reduced in size and is inexpensive. However, the semiconductor switch 14 is not limited to the semiconductor switch and may be any circuit that constitutes a circuit switching means.
The control unit 15 determines whether a standby command is issued to the ECU 2 from the standby signal 21, the door closing signal 22, and the door lock signal 23 input to the control unit 15, and the ECU 2 is in a standby state from the current value of the current sensor 13. Determine whether it is in Based on the determination result, an on / off command is issued to the relay 11 and the semiconductor switch 14.

  FIG. 2 is a time chart of the value of the current flowing through the ECU 2 and the operation of the relay 11 and the semiconductor switch 14 in the vehicle dark current measuring apparatus 10. In this embodiment, the ECU 2 has a current value of 5 A in the activated state, but when the ignition key is in the accessory position and the electrical component is not operating, the current value is 50 mA, the ignition key is turned off, and the ECU 2 Is in a standby state, the current value is 10 mA.

When the ECU 2 determines that the ECU 2 is in a standby state based on the signals 21 to 23 at time t1, the semiconductor switch 14 is turned on. After a certain period of time, the control unit 15 confirms that the value of the current flowing through the current measurement circuit 12 is below the threshold value.
At this time, since both the relay 11 and the semiconductor switch 14 are on, a part of the current flowing through the ECU 2 also flows through the current measurement circuit 12. In this embodiment, if a current about 1/10 of that of the relay 11 flows in the current measurement circuit 12, a current of 1 mA flows in the current measurement circuit 12. For example, a value obtained by adding 50% to 1 mA is determined as the threshold value. If the measured value of the current sensor 13 is smaller than the threshold value, it is determined that the ECU 2 is in a standby state.

If the measured value of the current sensor 13 is smaller than the threshold value, the relay 11 is turned off at time t2.
When the relay 11 is turned off, the current (dark current) in the standby state of the ECU 2 flows to the current measuring circuit 12, and the current sensor 13 measures the dark current.
When the ECU 2 is activated and an activation command for the ECU 2 is input to the control unit 15, the relay 11 is turned on at time t3, and the semiconductor switch 14 is turned off at time t4 after a predetermined time has elapsed. If the relay 11 is turned on, the current flows through the relay 11 to the ECU 2.

FIG. 3 is a flowchart showing the operation of the vehicle dark current measuring apparatus 10 according to the present invention.
In step S1, it is determined whether or not the standby signal 21 is input to the control unit 15. If the standby signal 21 is input, it is determined that a standby command has been issued to the ECU 2, and the process proceeds to step S2. If no standby command is issued, return to start.
In step S <b> 2, it is determined whether the door closing signal 22 is input to the control unit 15. If the door close signal 22 is input, it is determined that a standby command has been issued, and the process proceeds to step S3. If the door close signal is not input, return to the start.
In step S <b> 3, it is determined whether or not the door lock signal 23 is input to the control unit 15. If the door lock signal 23 is input, the door is locked and the occupant is out of the vehicle, so it is determined that a standby command is issued to the ECU 2, and the process proceeds to step S4. If the door lock signal is not input, return to the start.

In step S4, the control unit 15 issues a command to turn on the semiconductor switch 14, and turns on the semiconductor switch 14.
In step S5, the time is elapsed for a predetermined time. This is to prevent the semiconductor switch 14 in S4 from being turned on and the relay 11 from S7 from being turned off at the same time and the load being cut off from the battery.
In step S6, the current value measured by the current sensor 13 is compared with the magnitude of the threshold value. If the current value is smaller than the threshold value, it is determined that the ECU 2 is in a standby state, and the process proceeds to S7. If it cannot be determined that the current value is smaller than the threshold value, S6 is repeated until the ECU 2 enters a standby state and the current value becomes smaller than the threshold value, and the current value is compared with the threshold value.
In step S7, the control unit 15 issues a command to turn off the relay 11, and turns off the relay 11.

In step S8, it is determined whether a start command is issued to the ECU 2. If a start command has been issued to the control unit 15, the process proceeds to S9. If the start command is not issued, S8 is repeated until the start command is issued. If a start command is issued to the ECU 2, the door close signal 22 and the door lock signal 23 are not detected, and the process proceeds to S9. This is to prevent current in the activated state from flowing through the current measuring circuit 12 when the ECU 2 is in the activated state even if each signal is not detected.
In step S9, the control unit 15 issues a command to turn on the relay 11, and the relay 11 is turned on.
In step S10, time is elapsed for a predetermined time. This is to prevent the load from being completely cut off from the battery because both are turned off simultaneously due to the difference in operating speed between the semiconductor switch 14 and the relay 11.
In step S11, the control unit 15 issues a command to turn on the semiconductor switch 14, and turns on the semiconductor switch 14.
After all the steps are completed, the process returns to the start and waits for a standby command to be issued to the ECU 2.

  In this embodiment, the door close signal and the door lock signal are used to confirm whether the ECU 2 has received a standby command. In addition to these signals, the ignition key having a wireless communication function is used. An infrared sensor that detects a communication situation or an occupant in an automobile, a pressure sensor that detects an occupant in a seat, or the like may be used.

FIG. 4 shows a second embodiment of the vehicle power supply control device 20 using the vehicle dark current measuring device 10 shown in claim 2.
The vehicle power supply control device 20 includes a vehicle dark current measuring device 10, a control means 21, and a relay 22 that constitutes a circuit opening / closing means.
The vehicle dark current measuring apparatus 10 is the same as that shown in FIG.
The control means 21 receives the dark current value from the vehicle dark current measuring device 10 and compares it with a preset threshold value. The ECU 2 is in an activated state or malfunctions even though the ECU 2 receives a standby command. Detects abnormal operation. When the ECU 2 is performing an abnormal operation, the control means 21 cuts off the battery 1 and the ECU 2 to prevent the battery from running out.
The control means 21 can be replaced by the control unit 15 and the relay 22 can be replaced by the semiconductor switch 14. That is, it is possible to include the function of the vehicle power supply control device 20 while providing the same configuration as the vehicle dark current measuring device 10 of FIG. 1 without newly providing the control means 21 and the relay 22.

It is a block diagram of the dark current measuring device for vehicles which is the 1st example. It is a time chart of the dark current measuring device for vehicles. It is a flowchart showing operation | movement of the dark current measuring apparatus for vehicles. It is a block diagram of the vehicle power supply control apparatus which is a 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle power supply control apparatus 11 Relay 12 Current measurement circuit 13 Current sensor 14 Semiconductor switch 15 Control unit 20 Vehicle power supply control apparatus 21 Control means 22 Relay

Claims (3)

A relay interposed in a circuit connecting the battery and the load;
A current measurement circuit connected in parallel with the relay, in which a current sensor for current measurement and a semiconductor switch are connected in series;
A control unit connected to the relay, the semiconductor switch and the current sensor;
The control unit controls opening and closing of the relay and the semiconductor switch, and turns on the relay when receiving a load start signal and turns off the semiconductor switch, and turns off the semiconductor switch while receiving the load standby signal (sleep signal). A dark current measuring device for a vehicle that turns on the semiconductor switch and enables the dark current to be supplied to the current sensor.   2. The vehicle dark current measuring device according to claim 1, wherein the control unit is configured to turn on the semiconductor switch before turning off the relay and to turn off the semiconductor switch after turning on the relay.   Based on the current value detected by the dark current measuring device according to claim 1 or 2, the circuit opening / closing means connected to the load is connected to or cut off from the battery to supply or cut off power to the load. A vehicle power supply control device.

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