IN-VEHICLE ELECTRONIC CONTROL UNIT AND POWER FEEDING CONTROL METHOD OF THE SAME

• US 20140257632A1
• Filed: 09/06/2013
• Published: 09/11/2014
• Est. Priority Date: 03/05/2013
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: KANZAKI, Shozo, HASHIMOTO, Koji
• Granted Patent: US 9,162,639 B2
• Time in Patent Office: Days
• US Class Current: 701/36
• CPC Class Codes: B60R 16/033 characterised by the use of electrical cells or batteries for propulsion puposes B60K1/04; supplying batteries to, or removing batteries from, vehicles B60S5/06; testing of charge state G01R31/36
• CPC Class Codes: H02H 11/003 using a field effect transistor as protecting element in one of the supply lines

Abstract

When a power supply switch is fed with power from a DC power supply and closed, a power supply unit starts power feeding to an opening and closing command generation unit and continues the power feeding by a self-hold command signal from the opening and closing command generation unit. A reverse connection protective element is a field-effect transistor connected in series to the power supply switch and driven to conduct current in an energization direction of an internal parasitic diode when the power supply is connected in proper polarity. Even when a supply fault abnormality is occurring due to fault contact between a positive-side wire of an in-vehicle electrical load connected to the reverse connection protective element and a positive-electrode wire of the DC power supply, the self-hold command signal is cancelled by determining that the power supply switch is opened while the reverse connection protective element is opened.

Claims

1. An in-vehicle electronic control unit, comprising:

a load opening and closing element which is connected in series to apart or all of in-vehicle electrical load groups fed with power from a DC power supply;

an opening and closing command generation unit which supplies an opening and closing command signal to the load opening and closing element according to a driving condition of a vehicle; and

a power supply unit which feeds power to the opening and closing command generation unit by generating a predetermined stabilizing voltage when fed with power from the DC power supply in response to a manual power supply switch which is now closed, wherein;

the power supply switch feeds power to an in-vehicle electrical load which is the part or all of the in-vehicle electrical load groups via a reverse connection protective element;

the opening and closing command generation unit generates a self-hold command signal once the power supply switch is closed and power is fed from the power supply unit, so that a power feeding operation by the power supply unit is maintained even when the power supply switch is opened;

the reverse connection protective element is a field-effect transistor which includes a parasitic diode, and is configured in such a manner that a gate voltage is applied by a drive transistor so that the reverse connection protective element is driven to close in a direction same as an energization direction of the parasitic diode when the DC power supply is connected in proper polarity, whereas the reverse connection protective element does not conduct current when the DC power supply is connected in reversed polarity by error and when the power supply unit stops feeding power;

the opening and closing command generation unit receives an input of a monitor signal which is used to monitor an input-side voltage of the reverse connection protective element, which is an output voltage of the power supply switch, and to determine that the power supply switch is opened when the input-side voltage has a value less than a predetermined value, and confirms open and close states of the power supply switch even when the input-side voltage is as high as or higher than a voltage of the predetermined value by monitoring the input-side voltage while the reverse connection protective element is opened;

the opening and closing command generation unit stops power feeding by the power supply unit by cancelling the self-hold command signal after a predetermined delay time upon detection of an open-circuit state of the power supply switch; and

the drive transistor is changed to an open-circuit state when the power feeding by the power supply unit stops and the reverse connection protective element is changed to an open-circuit state even when a supply fault abnormality is occurring due to fault contact between an output wire of the reverse connection protective element and a positive-electrode wire of the DC power supply, so that the power supply unit is not started again while the power supply switch is opened.

2. The in-vehicle electronic control unit according to claim 1, wherein:

the opening and closing command generation unit monitors whether the power supply switch is closed in one of a constant manner and a high-frequent first cycle and determines whether the power supply switch is opened by periodically opening the reverse connection protective element in a low-frequent second cycle, so that the opening and closing command generation unit drives the reverse connection protective element to close immediately when the power supply switch is closed.

3. The in-vehicle electronic control unit according to claim 1, wherein:

the opening and closing command generation unit receives an input of a power feeding monitor signal which is a logic signal used to monitor an output voltage of the reverse connection protective element; and

when the opening and closing command generation unit generates an open-circuit command for the reverse connection protective element, the opening and closing command generation unit compares logic states of a voltage monitor signal which is a logic signal used to monitor the input-side voltage of the reverse connection protective element and the power feeding monitor signal, and determines that the supply fault abnormality is occurring when the output-side voltage of the reverse connection protective element is detected but the input-side voltage is not.

4. The in-vehicle electronic control unit according to claim 1, wherein:

the reverse connection protective element driven to open and close by the opening and closing command generation unit is controlled to open and close via the drive transistor in response to one of a voltage in proportion to an output current of the reverse connection protective element, a difference monitor voltage in proportion to a difference value between the input-side voltage and the output-side voltage, and a difference voltage between a power supply monitor voltage in proportion to the input-side voltage and a power feeding monitor voltage in proportion to the output-side voltage; and

the reverse connection protective element is driven to close on the ground that a feeding current as high as or higher than a predetermined threshold current is flowing in a conduction direction of the parasitic diode, and a close-circuit command is cancelled at least when the input-side voltage is as high as or lower than the output-side voltage.

5. The in-vehicle electronic control unit according to claim 4, wherein:

a differential amplifier is connected to the opening and closing command generation unit;

the differential amplifier detects a normal feed direction voltage generated when the input-side voltage of the reverse connection protective element exceeds the output-side voltage in response to one of a voltage across the reverse connection protective element, a voltage across a current detection resistor connected in series to the reverse connection protective element, and a difference monitor voltage in proportion to a voltage across a series circuit made up of the reverse connection protective element and the current detection resistor; and

the reverse connection protective element is driven to close via the drive transistor on the ground that an output signal voltage of the differential amplifier has a value equal to or greater than a predetermined value corresponding to the threshold current.

6. The in-vehicle electronic control unit according to claim 5, wherein:

input terminals of the differential amplifier are connected to each other by a pair of clip diodes;

the respective input terminals of the differential amplifier are connected to both ends of a measured constant voltage used to measure the difference monitor voltage via input resistors;

a leak current interruption element is connected in series to one of the input resistors on a positive input side of the differential amplifier; and

the leak current interruption element is closed as the drive transistor is driven to close, and interrupted when the reverse connection protective element is opened.

7. The in-vehicle electronic control unit according to claim 1, wherein:

the load opening and closing element is a field-effect transistor located upstream of the in-vehicle electrical load and connected to the reverse connection protective element in a lower stream location;

the opening and closing command generation unit receives an input of a load monitor signal used to monitor an output voltage of the load opening and closing element;

the opening and closing command generation unit monitors the load monitor signal each time the opening and the closing command generation unit changes the opening and closing command signal for the load opening and closing element to an open-circuit command, and determines that an indirect supply fault abnormality is occurring due to an output wire of the load opening and closing element coming in fault contact with the positive-electrode wire of the DC power supply when the output voltage of the load opening and closing element is generated; and

the opening and closing command generation unit further generates an open-circuit command for the reverse connection protective element upon detection that the indirect supply fault abnormality is occurring to determine whether the power supply switch is opened, and immediately drives the reverse connection protective element to close when the power supply switch is closed.

8. The in-vehicle electronic control unit according to claim 1, wherein:

the load opening and closing element is a field-effect transistor located upstream of the in-vehicle electrical load and connected to the reverse connection protective element in a lower stream location, and provided with a supply fault determination circuit which determines whether or not an indirect supply fault abnormality is occurring due to an output wire of the load opening and closing element coming in fault contact with the positive-electrode wire of the DC power supply by monitoring an output voltage of the load opening and closing element each time a close-circuit drive command for the load opening and closing element is cancelled; and

the opening and closing command generation unit generates an open-circuit command for the reverse connection protective element when the supply fault determination circuit detects the indirect supply fault abnormality to determine whether the power supply switch is opened, and immediately drives the reverse connection protective element to close when the power supply switch is closed.

9. A power feeding control method of an in-vehicle electronic control unit including:

a load opening and closing element which is connected in series to a part or all of in-vehicle electrical load groups fed with power from a DC power supply;

an opening and closing command generation unit which supplies an opening and closing command signal to the load opening and closing element according to a driving condition of a vehicle; and

a power supply unit which feeds power to the opening and closing command generation unit by generating a predetermined stabilizing voltage when fed with power from the DC power supply in response to a manual power supply switch which is now closed, and configured in such a manner that the power supply switch feeds power to an in-vehicle electrical load which is the part or all of the in-vehicle electrical load groups via a reverse connection protective element, wherein;

a gate voltage is applied by a drive transistor to the reverse connection protective element which is a field-effect transistor including a parasitic diode when the DC power supply is connected in proper polarity so that the reverse connection protective element is driven to close in a direction same as an energization direction of the parasitic diode, whereas the reverse connection protective element does not conduct current when the DC power supply is connected in reversed polarity by error and when the power supply unit stops feeding power;

the opening and closing command generation unit includes a RAM memory, a non-volatile program memory, a non-volatile data memory which is one of a partial region of the non-volatile program memory and a separate memory connected thereto, and a microprocessor operating in cooperation with a multi-channel A-to-D converter;

the microprocessor generates a self-hold command signal once the power supply switch is closed and power is fed from the power supply unit, so that a power feeding operation by the power supply unit is maintained even when the power supply switch is opened;

the microprocessor periodically monitors whether the power supply switch is still closed;

the microprocessor determines that the power supply switch is opened when an input-side voltage of the reverse connection protective element is not generated at least while the reverse connection protective element is opened and stops the power feeding operation by the power supply unit by cancelling the self-hold command signal after a predetermined delay and stand-by period; and

the microprocessor determines that a supply fault abnormality is occurring due to a fault contact between an output wire of the reverse connection protective element and a positive-electrode wire of the DC power supply when an output-side voltage of the reverse connection protective element is generated but the input-side voltage is not and saves at least abnormality occurrence history information by writing the abnormality occurrence history information in the non-volatile data memory in the delay and stand-by period.

10. The power feeding control method of an in-vehicle electronic control unit according to claim 9, wherein:

in a case where the microprocessor detects the supply fault abnormality immediately after the power supply switch is interrupted, the microprocessor performs in one of the following manners;

the microprocessor cancels the self-hold command signal after the microprocessor notifies the abnormality for a predetermined time by extending at least the delay and stand-by period; and

the microprocessor reads out supply-fault abnormality occurrence history information in the non-volatile data memory at least when the power supply switch is closed again and, in a case where the supply fault abnormality had occurred when the power supply switch was interrupted last time, notifies the abnormality which had occurred.

11. The power feeding control method of an in-vehicle electronic control unit according to claim 9, wherein:

the microprocessor monitors the input-side voltage of the reverse connection protective element with a high frequency as often as or less frequent than a first cycle T1 while the reverse connection protective element is driven to close and determines that the power supply switch is opened when the input-side voltage is not generated;

even when the input-side voltage of the reverse connection protective element is generated, the microcomputer monitors the input-side voltage of the reverse connection protective element by periodically opening the reverse connection protective element with a low frequency as often as or less frequent than a second cycle T2 (T2>

T1) which is less frequent than the first cycle T1 and determines that the power supply switch is opened when the input-side voltage is not generated; and

a time zone over which the reverse connection protective element is opened within a period of the second cycle T2 is a time zone T0 which is a part within the first cycle T1.

12. The power feeding control method of an in-vehicle electronic control unit according to claim 9, wherein:

the input-side voltage of the reverse connection protective element is monitored in one of a constant manner and a periodical manner while the reverse connection protective element is driven to close, and it is determined that the power supply switch is opened when the input-side voltage is not generated; and

signal voltages on an input side and an output side of the reverse connection protective element are compared relatively with each other in one of a constant manner and a periodical manner even when the input-side voltage is generated, and the reverse connection protective element is opened when the input-side voltage is not higher than the output-side voltage to make determinations as follows,

it is determined that the power supply switch is closed when the input-side voltage is generated,

it is determined that the power supply switch is opened when neither the input-side voltage nor the output-side voltage is generated, and

it is determined that the power supply switch is opened but a supply fault abnormality is occurring when the output-side voltage is generated but the input-side voltage is not.

13. The power feeding control method of an in-vehicle electronic control unit according to claim 9, wherein:

a plurality of in-vehicle electrical loads, to each of which the load opening and closing element is connected in series, are connected in parallel with the reverse connection protective element in a lower stream location;

the load opening and closing element which is a field-effect transistor is connected in series to a particular electrical load among a plurality of the in-vehicle electrical loads in an upper stream location;

an open-circuit output voltage of the load opening and closing element is monitored each time the opening and closing command signal for the load opening and closing element is changed to an open-circuit command;

it is determined that an indirect supply fault abnormality is occurring due to an output wire of the load opening and closing element coming in fault contact with the positive-electrode wire of the DC power supply when the open-circuit output voltage is generated; and

when it is determined that the indirect supply fault abnormality is occurring, the load opening and closing element is forcedly closed until the opening and closing command signal is changed to the open-circuit command again.