JP2003092874A - Power supply for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the entire structure while enhancing the reliability by providing two power supply circuits having a power conversion function in a power supply corresponding to a high voltage battery. SOLUTION: A power supply circuit 4 supplies control units 13 and 15 with a low voltage by converting the high voltage of a battery power supply 1. When the power supply circuit 4 is abnormal, a control circuit 12 switches transistors 7, 8 and 9 from on to off and switches transistors 10 and 11 from off to on thus supplying power from a power supply circuit 5 to a main control unit 13. Consequently, the structure of the entire power supply system including the battery power supply 1, a power supply unit 3, the control units 13 and 15, and the like, can be simplified in a vehicle of high voltage specification and the reliability can be enhanced by the surge voltage interrupting function of the transistors 7-11 or the two power supply circuits 4 and 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for a vehicle, which is preferably used in a vehicle such as an automobile.
The present invention relates to a vehicle power supply device configured to supply power to a plurality of control units from a high-voltage battery power supply.

[0002]

2. Description of the Related Art In recent years, various devices such as automobiles are often equipped with various devices having large power consumption. And as a power supply device mounted on such a vehicle,
In addition to a commonly used battery power source having a voltage of about 12 to 14 V, a battery power source having a high voltage of, for example, 30 V or more is known (for example, Japanese Patent Laid-Open No. 2000-31444). etc).

A vehicle power supply device of this type according to the prior art drives a device with large power consumption, such as an electric motor or an electric brake device, in a normal operating state by a high-voltage battery to drive a car radio, an interior light, or the like. The accessory device is driven by a low voltage battery.

Vehicles such as automobiles are equipped with various control units for controlling, for example, an engine, an automatic transmission, a brake device and a power steering. And, these control units, for example, because the control unit mounted on a vehicle of a general specification having only a low voltage battery is used,
These are connected to a low voltage battery.

[0005]

By the way, in the above-mentioned prior art, since the high voltage battery and the low voltage battery are mounted on the vehicle, the size of the power supply device is increased by the two batteries, and the weight of the entire vehicle is increased. There is a problem that

Therefore, for example, a configuration in which the low-voltage battery is eliminated and the high-voltage battery supplies power to a plurality of control units via a voltage conversion circuit such as a DC / DC converter can be considered. However, in this case, for example, when the voltage conversion circuit fails, all the control units become inoperable, so a high-cost voltage conversion circuit that can withstand a large surge voltage applied from the high-voltage battery side is required. Unless it is used, there is a problem of reduced reliability.

In addition, when the voltage conversion circuit fails due to a short circuit or the like, a high voltage is directly applied to all control units from the high voltage battery, so that a large number of parts including each control unit and the like fail in a chain. There is fear.

In order to avoid this chain-like failure, for example, a dropper type power supply, a chopper type switching regulator, etc. are provided for each control unit,
If the voltage conversion is performed for each control unit, there is a problem that the overall cost increases.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to reduce the size of a power supply device including a battery and to control even if a part of the power supply device fails. An object of the present invention is to provide a vehicle power supply device capable of supplying necessary power to a unit and improving reliability while suppressing cost.

[0010]

In order to solve the above-mentioned problems, the invention of claim 1 has a first power supply circuit and a second power supply circuit which are supplied with power from a battery power source, and has the first power supply circuit. The power supply circuit connects a first switch between the input side of the power supply circuit and the battery power supply, and connects a second switch between the output side of the first power supply circuit and the first control unit. , Connecting a third switch between the output side of the first power supply circuit and the second control unit, and connecting a fourth switch between the output side of the first power supply circuit and the ground side The second power supply circuit has an input side connected to the battery power supply, and a fifth switch is connected between the output side of the second power supply circuit and the first control unit. The first power source is fed by a second power circuit. Wherein when an abnormality occurs in the road first
A control circuit for stopping the control circuit and turning on and off the first to fifth switches respectively to supply power from the second power supply circuit, and the control circuit includes a control circuit for supplying power to the first power supply circuit. In order to monitor the state of the output voltage, a configuration is adopted in which a voltage monitoring terminal to which the output side of the first power supply circuit is connected is provided.

With this configuration, the first power supply circuit can convert, for example, the battery voltage into a predetermined voltage and output the voltage to the first and second control units, and the control circuit outputs the normal output voltage. Whether or not it can be monitored by the voltage monitoring terminal. When the output voltage is normal, the first power supply circuit can supply power to the control units via the first to third switches to operate them. Further, when the output voltage of the first power supply circuit becomes abnormal, for example, the battery voltage is converted into a predetermined voltage by the second power supply circuit, and this voltage is sent to the first control unit via the fifth switch. Since it can be supplied, for example, only the first control unit necessary for driving the vehicle can be operated in the backup state.

According to a second aspect of the present invention, at least one of the first and second control units is provided with a load which is fed from the battery power source and controlled by the control unit. A sixth switch that is turned on and off by the control circuit is connected between the load and the load.

Thus, for example, between the various loads controlled by the control unit and the battery power source, the low voltage wiring for supplying power from the power supply circuit to the control unit and the insulated high voltage wiring are connected. You can
A sixth switch can be provided in the middle of the high voltage wiring. The control circuit can switch the sixth switch to OFF when, for example, the low-voltage wiring arranged between the power supply circuit and the control unit is short-circuited with the high-voltage wiring. It is possible to prevent a high voltage from flowing from the voltage wiring to the control unit side.

By configuring each switch with a transistor as in the third aspect of the invention, the switch can be made smaller and lighter, and its operating characteristics and the like can be appropriately set as required.

Further, by constructing each switch by a relay as in the invention of claim 4, the structure of the switch can be simplified and the cost can be reduced.

According to the invention of claim 5, a resistor is provided between the battery power supply and the input side of the second power supply circuit. Thus, for example, when a large surge voltage or the like is generated on the battery power supply side, the surge voltage or the like applied to the input side of the second power supply circuit can be suppressed by the voltage drop due to the resistance, and the second power supply circuit is protected. can do.

Further, according to the invention of claim 6, the control circuit outputs a fail signal to the first control unit when an abnormal voltage is input to the voltage monitoring terminal from the output side of the first power supply circuit. A fail signal terminal is provided.

Thus, for example, when the control circuit detects an output abnormality of the first power supply circuit, the control circuit can output a fail signal to the first control unit, thereby operating the first control unit in a power saving state or the like. Can be made. Therefore, for example, the second power supply circuit can be configured by a backup power supply circuit that supplies less power than the first power supply circuit, and the second power supply circuit can easily drive the first control unit. .

Further, according to the invention of claim 7, the control circuit turns on the first to third switches when a normal voltage is input to the voltage monitoring terminal from the output side of the first power supply circuit. Hold it and turn off the 4th and 5th switches
When the input voltage to the voltage monitoring terminal becomes abnormal, the first to third switches are turned off and the fourth and fifth switches are turned on.

Thus, when the output voltage of the first power supply circuit is normal, power can be supplied to each control unit from the battery power supply via the first power supply circuit, and at this time, the second power supply circuit can be supplied.
The power supply circuit and the control unit can be disconnected. Further, when the output voltage of the first power supply circuit becomes abnormal, the first power supply circuit can be disconnected from both the battery power supply and each control unit and grounded to the ground, and the second power supply circuit and the control unit can be connected to each other. You can connect between them.

Further, according to the invention of claim 8, the control circuit holds the sixth switch ON when a normal voltage is input to the voltage monitoring terminal from the output side of the first power supply circuit, The sixth switch is turned off when the input voltage to the voltage monitoring terminal is higher than the normal voltage.

Thus, when the output voltage of the first power supply circuit is normal, various loads can be supplied from, for example, the battery power supply through the high-voltage wiring, the sixth switch, and the like. Further, for example, even if the first switch is turned off, if the output voltage of the first power supply circuit is higher than the normal voltage, it is determined that the high-voltage wiring is short-circuited to the output side of the first power supply circuit. The sixth switch can be turned off, and a high voltage can be prevented from sneaking into the control unit side from the high voltage wiring.

Further, according to the invention of claim 9, an active clamp circuit for disconnecting the first power supply circuit side from the abnormal voltage when the abnormal voltage is generated on the battery power supply side is connected to the first switch. It is configured.

Thus, for example, when an abnormal voltage such as a surge voltage occurs on the battery power supply side, the active clamp circuit blocks the abnormal voltage from being applied to the first power supply circuit side via the first switch. You can

According to the tenth aspect of the present invention, the control circuit is provided with a control signal circuit held in a floating state with respect to the ground, and the control signal circuit controls the first switch to be turned on and off. It is configured to output a signal.

As a result, the first switch is turned on and off by a control signal circuit such as a charge pump circuit.
You can F Then, for example, when a large surge voltage or the like is applied to the first switch from the battery power source side, since the control signal circuit is held in a floating state with respect to the ground, a large voltage is applied between the terminals of the first switch. Can be prevented and this switch can be protected.

Further, according to the invention of claim 11, the first
The value of the saturation current flowing through the switch is larger than the sum of the current values that are normally supplied to the first and second control units, and is larger than the current value corresponding to the abnormal voltage generated on the battery power supply side. The configuration is set to a small value.

As a result, a sufficient current can be supplied to the first and second control units via the first switch and the like. Also, for example, when a large abnormal voltage is applied to the first switch from the battery power source side,
Since the value of the current flowing through the first switch does not become larger than the saturation current value, it is possible to protect the first power supply circuit, the first and second control units, etc. connected to the output side.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a vehicle power supply device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Here, FIGS. 1 and 2 show a first embodiment according to the present invention. In this embodiment, a vehicle power supply device mounted on a vehicle such as an automobile will be described as an example.

Reference numeral 1 denotes a high-voltage battery power source mounted on a vehicle, and the battery power source 1 generates a high voltage of, for example, about 30 to 50 V with respect to the earth 2.

Reference numeral 3 denotes a power supply unit connected to the battery power supply 1. The power supply unit 3 includes power supply circuits 4 and 5, which will be described later.
A plurality of connection terminals 3A, 3B, 3C, including the transistors 7, 8, 9, 10, 11 and the control circuit 12 are included.
It has 3D etc. Then, the power supply unit 3 applies the high voltage supplied from the battery power supply 1 to, for example, 5 to 15
The voltage is converted into a low voltage of about V and this low voltage is supplied to the control units 13 and 15 described later.

Reference numeral 4 denotes a first power supply circuit which constitutes a main power supply circuit of the power supply unit 3, and the first power supply circuit 4 is connected to the battery power supply 1 via the transistor 7 as an input terminal 4
A, the output terminal 4B connected to the control units 13 and 15 via the transistors 8 and 9, and the control circuit 1
Operation control terminal 4 for operating (ON) and stopping (OFF) the power supply circuit 4 according to a control signal input from
Have C and.

The power supply circuit 4 is, for example, DC / DC.
When a high voltage is input from the battery power supply 1 to the input terminal 4A, it has a voltage conversion circuit (not shown) including a converter, a switching regulator, a dropper type circuit, and the like.
This voltage is converted into a low voltage corresponding to the control units 13 and 15 and output from the output terminal 4B.

Reference numeral 5 is a second power supply circuit which constitutes an auxiliary power supply circuit of the power supply unit 3, and although the second power supply circuit 5 has a voltage conversion circuit and the like similar to the power supply circuit 4,
The capacity (supply power) is set smaller than that of the power supply circuit 4. The power supply circuit 5 has an input terminal 5A connected to the battery power supply 1 side via a resistor 6, an output terminal 5B connected to the control unit 13 via a transistor 11, and a power supply terminal 12A of the control circuit 12. The power supply terminal 5C for supplying power is provided.

The power supply circuit 5 is, for example, the power supply circuit 4
When the battery etc. fails, the input terminal 5A from the battery power source 1
By converting a high voltage input to the control unit 13 and outputting a low voltage from the output terminal 5B, power is supplied to the control unit 13 instead of the power supply circuit 4. In this case, the resistor 6
Is for reducing the surge voltage applied to the power supply circuit 5 from the battery power supply 1 side by the amount of voltage drop due to the resistor 6.

Reference numeral 7 is a transistor as a first switch connected between the battery power supply 1 and the input terminal 4A of the power supply circuit 4, and the first transistor 7 is, for example, a MOS.
It is composed of a high power type switching element including an FET, an IGBT and the like.

In the transistor 7, one of the drain electrode and the source electrode of the transistor 7 is connected to the battery power source 1, the other electrode is connected to the power source circuit 4, and the gate electrode thereof is a control circuit described later. Twelve transistor control terminals 12C are connected. The transistor 7 is turned on / off in response to a control signal output from the transistor control terminal 12C of the control circuit 12 to connect / disconnect the power supply circuit 4 to / from the battery power supply 1.

The current characteristics of the transistor 7 will now be described. As shown in FIG. 2, the magnitude (saturation current value) Io of the drain current flowing between the drain and source electrodes in a saturated state is determined by the control units 13, 15 and the like. The amount of current flowing between the drain and source electrodes when a surge voltage or the like is applied from the battery power source 1 side that is larger than the sum of current values (consumption current value) Ir that are normally energized. It is set smaller than the value (overcurrent value) Ie (Ir <Io <Ie). As a result, the transistor 7 is configured to suppress the magnitude of the current supplied to the control units 13, 15 and the like to the saturation current value Io or less and protect them.

Reference numeral 8 is a transistor as a second switch connected between the output terminal 4B of the power supply circuit 4 and the control unit 13, and the second transistor 8 is of a high power type, similar to the transistor 7. It is composed of switching elements. The transistor 8 is turned on / off by the control circuit 12 to connect / disconnect the control unit 13 to / from the power supply circuit 4.

Reference numeral 9 denotes a transistor as a third switch which is connected between the output terminal 4B of the power supply circuit 4 and the control unit 15. The third transistor 9 connects the control unit 15 to the power supply circuit 4. It connects and disconnects.

Reference numeral 10 denotes a transistor as a fourth switch connected between the output terminal 4B of the power supply circuit 4 and the ground 2 side. The fourth transistor 10 is turned on and off by the control circuit 12, and the power supply circuit is turned on. 4 is configured to be grounded at the output terminal 4B side to the earth 2.

Reference numeral 11 denotes a transistor as a fifth switch connected between the output terminal 5B of the power supply circuit 5 and the control unit 13, and the fifth transistor 11
Is for connecting and disconnecting between the power supply circuit 5 and the control unit 13 depending on whether the power supply circuit 4 or the like is operating normally.

Reference numeral 12 is a control circuit for controlling the power supply unit 3. The control circuit 12 is composed of, for example, a semiconductor IC,
Power supply terminal 12A connected to power supply terminal 5C of power supply circuit 5
And a power supply circuit control terminal 12B connected to the operation control terminal 4C of the power supply circuit 4, and the transistors 7, 8, 9, 1.
Control terminals 12C, 12D, 12E, 12F, 12 for transistors respectively connected to the gate electrodes of 0 and 11
G, a voltage monitoring terminal 12H connected to the output terminal 4B side of the power supply circuit 4 and receiving the output voltage thereof, and a fail signal terminal 12J connected to the control unit 13.

Then, the control circuit 12 uses the voltage monitoring terminal 1
2H is used to monitor whether or not the output voltage of the power supply circuit 4 is in a normal state, and when the voltage value is within a normal range,
The transistors 7, 8 and 9 are held in the ON state, and the transistors 10 and 11 are held in the OFF state. This allows
Electric power is supplied from the battery power supply 1 to the control units 13 and 15 via the power supply circuit 4.

Further, the control circuit 12 outputs a stop signal from the power supply circuit control terminal 12B to the operation control terminal 4C when the output voltage of the power supply circuit 4 goes out of the normal range and becomes abnormally large. The power supply circuit 4 is stopped, the transistors 7, 8 and 9 are turned off, and the transistors 10 and 11 are turned on. As a result, the power supply circuit 4
Is the battery power source 1 and the control units 13 and 15
The control unit 13 is insulated from and is grounded to the earth 2, and power is supplied to the control unit 13 from the battery power supply 1 through the power supply circuit 5. Further, at this time, the control circuit 12 sends a fail signal informing the abnormality of the power supply circuit 4 from the fail signal terminal 12J.
3, and the control unit 13 is operated in a power saving mode in which power consumption is small.

Reference numeral 13 denotes a first control unit mounted on the vehicle. The first control unit 13 is
For example, it is configured to include a plurality of control units that control important devices such as an engine, an automatic transmission, and a brake device, and is connected to the transistor 8 side of the power supply unit 3 via the low voltage wiring 14 and the like.

When the power supply circuit 4 fails, the control unit 13 receives a fail signal from the control circuit 12 to operate in a backup state in which power consumption is suppressed, and the control unit 1 has a power saving function.
5 has a fail-safe function for compensating for the influence of the stoppage of No. 5.

Reference numeral 15 is a second control unit mounted on the vehicle, and the second control unit 15 is
For example, it is composed of multiple control units for controlling relatively insignificant devices such as power steering, power window, car navigation system,
It is connected to the transistor 9 side of the power supply unit 3 via the low voltage wiring 16 and the like. The control unit 15 is stopped when the power supply circuit 4 fails, for example, to save power consumption.

Further, various loads and the like controlled by the control units 13 and 15 are mounted on a vehicle such as an automobile. Then, these loads are directly connected to the battery power source 1 via a high-voltage wiring (neither is shown) or the like, and are operated by a high voltage supplied from the battery power source 1.

The vehicle power supply device according to the present embodiment has the above-mentioned structure, and its operation will be described below.

First, when the power supply circuit 4 is operating normally, the control circuit 12 holds the transistors 7, 8 and 9 in the ON state and turns off the transistors 10 and 11.
Held in a state. As a result, the high voltage of the battery power supply 1 is converted into a low voltage by the power supply circuit 4, and the low voltage can be stably supplied to the control units 13 and 15 via the transistors 7, 8 and 9. it can.

Also, for example, when the terminals of the battery power source 1 are momentarily disconnected during the power generation operation by the alternator, or when the battery terminals are disconnected during energy regeneration by the integrated starter generator (ISG). In this case, a large surge voltage (so-called battery dump surge) is generated on the battery power source 1 side, and this surge voltage may cause a failure such as an output abnormality in the power source circuit 4.

However, in this case, when the output abnormality of the power supply circuit 4 is detected by the voltage monitoring terminal 12H of the control circuit 12, the power supply circuit 4 is stopped and the transistors 7, 8,
9 is turned off and the transistor 10,
11 is turned on.

As a result, the power supply circuit 4 can be insulated from both the battery power supply 1 and the control units 13 and 15 by the transistors 7, 8 and 9, and the transistor 1 can be isolated.
Since the power supply circuit 4 can be held in the grounded state by 0, the surge voltage and the like generated on the battery power supply 1 side can be reliably cut off to the control units 13 and 15, and these can be protected from the surge voltage and the like.

The control unit 13 important for driving the vehicle can be driven by the auxiliary power supply circuit 5 through the transistor 11 in a power saving state, and the control unit 15 which is relatively unimportant can be stopped.
Accordingly, even if the power supply circuit 4 fails, the vehicle can be operated in the minimum state.

Thus, according to the present embodiment, the power supply unit 3 is provided with the power supply circuits 4 and 5, the first to fifth transistors 7, 8, 9, 10, and 11, the control circuit 12, and the like. Since the power supply unit 3 supplies power to the first and second control units 13 and 15, the high-voltage battery power supply 1 can directly supply power to various loads mounted on the vehicle, and the battery power supply 1 can be used. A high voltage supplied from a single power supply unit 3 is converted into a low voltage by a plurality of control units 13, 1.
5, respectively.

As a result, even in a vehicle of high voltage specifications, for example, only one type of battery power source 1 needs to be mounted, and components such as the conventional dropper type power source and chopper type switching regulator are individually controlled. Since it is not necessary to provide the units 13 and 15 to convert the power supply voltage, it is possible to reduce the cost of these components and the cost of the heat dissipation structure, and to include the battery power supply 1, the power supply unit 3, the control units 13, 15 In addition, the power supply system as a whole can be reduced in size and weight, and its structure can be simplified to reduce the overall cost.

Moreover, the power supply unit 3 includes the control circuit 1
Since two power supply circuits 4 and 5 that are switched and driven by 2 are provided, for example, when a large surge voltage is applied to the power supply circuit 4 and the output voltage of the power supply circuit 4 becomes abnormal, the control circuit The output abnormality of the power supply circuit 4 can be detected by the voltage monitoring terminal 12H of 12.

As a result, since the control circuit 12 can insulate and ground the power supply circuit 4 by the transistors 7 to 10, a surge voltage is applied to the control units 13 and 15 via the power supply circuit 4 and many control units are damaged. It is possible to reliably prevent each control unit from becoming unstable. Therefore, it is not necessary to use electronic parts having high insulation voltage for each control unit, and a large-scale protection circuit for protecting these parts can be omitted.

The backup power supply circuit 5 is
A minimum current can be supplied to the main control unit 13 via the transistor 11, and important devices such as an engine, an automatic transmission, and a brake device can be driven in a backup state, and reliability can be improved.

Further, since the control circuit 12 is provided with the fail signal terminal 12J for outputting the fail signal to the control unit 13, when the power supply device 4 fails, the control unit 13 is operated in the power saving state while the control unit 13 is operated. Fail-safe processing that complements the function of 15 can be executed, and reliability can be further improved. Also,
Since the capacity of the backup power supply circuit 5 can be set small corresponding to the power saving state of the control unit 13, the cost reduction can be promoted.

Further, the saturation current value Io of the first transistor 7 is set to be larger than the overall current consumption value Ir of the control units 13 and 15 and smaller than the overcurrent value Ie expected from the surge voltage. Therefore, by properly setting the gate voltage in advance, when the voltage on the battery power source 1 side is normal, for example, the transistor 7 can be operated at the operating point A in FIG. 2 where the power consumption of the transistor 7 is low. . And the battery power source 1
When a surge voltage etc. occurs on the side, the transistor 7
Since a current larger than the saturation current value Io does not flow through the power supply circuit 4 side through the transistor 7, most of the surge energy can be consumed by the transistor 7 while suppressing the magnitude of the overcurrent at the operating point B to the saturation current value Io or less. The power supply circuit 4, the control units 13, 15 and the like can be protected.

On the other hand, since the resistor 6 which does not affect the operation of the power supply circuit 5 whose power consumption is relatively small is arranged between the battery power supply 1 and the power supply circuit 5, for example, a large surge voltage on the battery power supply 1 side. When the above occurs, the surge voltage applied to the power supply circuit 5 can be reduced by the amount of the voltage drop due to the resistor 6, and the power supply circuit 5, the control unit 13 and the like can be protected.

Next, FIG. 3 shows a second embodiment according to the present invention. The feature of this embodiment is that a sixth switch is provided between the load controlled by the control unit and the battery power source. There is that. In this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 21 is a power supply unit connected to the battery power supply 1. The power supply unit 21 is similar to the power supply unit in the first embodiment, and the power supply circuits 4 and 5 and the first to fifth transistors 7 and 8 are provided. 9, 10, 11 and a control circuit 24, which will be described later, and the like, and a plurality of connection terminals 21A, 21B, 2
It has 1C, 21D, 21E, 21F and the like.

However, in the power supply unit 21, an intermediate portion of the high voltage wiring 22 for supplying a high voltage from the battery power source 1 to the loads 25 and 26, which will be described later, is arranged, and a transistor 23, which will be described later, is connected to this intermediate portion. Has been done.

Reference numeral 23 is a transistor serving as a sixth switch provided between the battery power source 1 and the loads 25 and 26. The transistor 23 is similar to the transistors 7 to 11 of the first embodiment. It is composed of a high power type switching element. And the transistor 23
Is turned on and off by the control circuit 24 to connect and disconnect the loads 25 and 26 to the battery power supply 1.

In this case, the transistor 23 does not have to be provided on all the high voltage wirings connected between the various loads mounted on the vehicle and the battery power source 1, and for example, the control unit 13 of each high voltage wiring is provided. , 15 together with the low voltage wirings 14, 16 for low voltage wiring 1
The configuration may be such that it is selectively provided for the high-voltage wirings 22 and the like arranged near 4, and 16.

Reference numeral 24 is a control circuit for controlling the power supply unit 3. The control circuit 24 is similar to the first embodiment, and the power supply terminal 24A, the power supply circuit control terminal 24B, and the transistor control terminals 24C, 24D. , 24E, 24F,
24G, 24H, a voltage monitoring terminal 24J and a fail signal terminal 24K.

When the output voltage of the power supply circuit 4 is within the normal range, the control circuit 24 causes the transistors 7,
The transistors 8 and 9 and the transistor 23 are kept in the ON state, and the transistors 10 and 11 are kept in the OFF state. When the output voltage of the power supply circuit 4 becomes abnormal,
Power supply circuit 4 is stopped and transistors 7, 8 and 9 are turned off
Switch to the state and turn on transistors 10 and 11
Switch to the state.

In this case, when the output voltage of the power supply circuit 4 has a voltage value larger than the normal range, the power supply circuit 4 and the transistor 7 are first turned off. When the voltage on the output terminal 4B side is large even in this OFF state, for example, the high-voltage wiring 22 and the low-voltage wiring 14, 1
It is determined that an abnormality such as a short circuit has occurred between the transistor 6 and 6, and not only the transistors 8 and 9, but also the transistor 23 is turned off.

25 and 26 are control units 13,
With various loads respectively attached to 15, the loads 25,
26 includes, for example, various actuators controlled by the control units 13 and 15,
Power is supplied from the battery power source 1 through the high-voltage wiring 22.

Thus, in this embodiment having such a configuration, it is possible to obtain substantially the same operational effects as those of the first embodiment. And, particularly in this embodiment,
Since the transistor 23 is provided on the high-voltage wiring 22, for example, when the high-voltage wiring 22 and the low-voltage wirings 14 and 16 are short-circuited, the transistor 23 is turned off to turn on the high-voltage wiring 2.
2 can be cut off, the high voltage of the battery power supply 1 can be surely prevented from sneaking into the control unit 13, 15 side via this short-circuited portion, and the reliability can be further enhanced.

Next, FIG. 4 shows a third embodiment according to the present invention, which is characterized in that an active clamp circuit is provided in the first switch.
In this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 31 is a control circuit for controlling the power supply unit. The control circuit 31 has a transistor control terminal 31A connected to the gate electrode of the transistor 7 and other transistors, as in the first embodiment. Terminal 31
B, 31C, and a power supply terminal excluding these terminals 31A to 31C, a power supply circuit control terminal, a transistor control terminal (none of which are shown), and the like.

Reference numeral 32 is an active clamp circuit provided in the control circuit 31, and the active clamp circuit 32 is
For example, the constant voltage diode 33 connected in the reverse direction between the drain electrode (D) and the gate electrode (G) of the transistor 7, the diode 34 connected in the forward direction between these electrodes, and the gate electrode (G ) And the source electrode (S), the gate bias circuit 35 is connected.

When, for example, a surge voltage from the battery power source 1 side is applied to the transistor 7, the potential of the drain electrode rises and exceeds the withstand voltage of the constant voltage diode 33, the potential of the drain electrode appears on the gate electrode. And a bias voltage corresponding to the difference between the withstand voltage of the constant voltage diode 33 is applied. As a result, the transistor 7 is turned on so that the potential difference between the drain and source electrodes becomes the bias voltage.

Therefore, the surge voltage applied to the transistor 7 is not applied to the power supply circuit 4 and the like connected to the source electrode side thereof, and the power supply circuit 4 can be cut off from the surge voltage by the active clamp circuit 32. Further, by setting the breakdown voltage of the transistor 7 to a value equal to or higher than the expected surge voltage in advance, both the transistor 7 and the power supply circuit 4 can be protected.

Thus, in this embodiment having such a configuration, it is possible to obtain substantially the same operational effects as those of the first embodiment. And, particularly in this embodiment,
The surge voltage applied to the transistor 7 can be absorbed as a voltage between the drain and the gate electrode by the active clamp circuit 32, and the reliability can be further improved.

Next, FIG. 5 shows a fourth embodiment according to the present invention. The feature of this embodiment is that the first switch is formed by using the control signal circuit held in a floating state with respect to the ground. It is configured to output a control signal to. In this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 41 is a control circuit for controlling the power supply unit. The control circuit 41 has a transistor control terminal 41A connected to the gate electrode of the transistor 7 and another transistor, as in the first embodiment. Terminal 41
B and 41C, and a power supply terminal excluding these terminals 41A to 41C, a power supply circuit control terminal, a transistor control terminal (all not shown), and the like.

Reference numeral 42 denotes a charge pump circuit (or bootstrap circuit) as a control signal circuit provided in the control circuit 41. The charge pump circuit 42 is provided between the drain electrode and the gate electrode of the transistor 7, for example. A constant voltage diode 43 connected in a direction, a diode 44 connected in a forward direction between these electrodes, a constant voltage diode 45 connected in a reverse direction between the gate electrode and the source electrode of the transistor 7, A resistor 46 connected in parallel with the constant voltage diode 45 between these electrodes, a capacitor 47, diodes 48 and 49, and an oscillation circuit 50, which will be described later, are included.

A gate electrode is connected to one side electrode of the capacitor 47 via a diode 48 in the reverse direction,
The source electrode is connected via the diode 49 in the forward direction. The other electrode and the drain electrode of the capacitor 47 are connected to the output side of the oscillation circuit 50. Then, when the control circuit 41 operates, the transistor 7 is turned on.
When the control signal is input to the oscillation circuit 50, the oscillation circuit 50 operates so that the potential of the gate electrode becomes higher than that of the source electrode, and the transistor 7 is turned on.

At this time, the source electrode and the gate electrode are
Since they are connected to the ground 2 via the capacitor 47, the oscillation circuit 50 and the like and are in a floating state where they are not directly grounded, they are held in a high impedance state with respect to the ground 2. Then, for example, when a surge voltage is applied while the transistor 7 is in the ON state, the potential of the source electrode also rises as the potential of the drain electrode rises. At this time, the potential of the gate electrode is higher than that of the source electrode. Rises by a certain amount. Therefore, a high voltage is not applied between any two electrodes of the three electrodes including the drain, the source and the gate, so that the transistor 7 can be protected.

Thus, in this embodiment having such a structure, it is possible to obtain substantially the same operational effects as those of the first embodiment. And, particularly in this embodiment,
The charge pump circuit 42 can suppress the voltage between the respective electrodes of the transistor 7 against the surge voltage and the like, and can further improve the reliability. Further, since the charge pump circuit 42 includes the active clamp circuit 32 used in the third embodiment, it is possible to obtain substantially the same operational effect as that of the third embodiment.

In each of the above-mentioned embodiments, the transistors 7, 8, 9, 10, and 10 are used as the first to sixth switches.
However, the present invention is not limited to this, and the relay 51 is provided between the battery power supply 1 and the power supply circuit 4 instead of the first transistor 7 as in the modification shown in FIG. 6, for example. May be connected, and the relay 51 may be turned on and off by the control circuit 12 '. Similarly, the second to sixth transistors 8, 9, 10, 1
A configuration may be used in which a relay is used instead of 1 and 23, whereby the cost of the power supply unit 3 can be reduced.

In the second embodiment, the loads 25 and 26 are provided on the two control units 13 and 15, but the present invention is not limited to this, and any one of the control units 13 and 15 can be used. The load may be provided only on one of the control units.

Further, in all the embodiments or configurations described above, one vehicle power supply device according to the present invention is not necessarily mounted in the vehicle. In this case, for example, the power supply device of the present invention is provided at a plurality of locations such as in front of the vehicle and inside the passenger compartment,
All of the above-mentioned effects can be obtained even if the power supplies are individually supplied to the control unit arranged in front of the vehicle and the control unit arranged inside the passenger compartment.

[0090]

As described above in detail, according to the first aspect of the invention, the power supply device has the first and second power supply circuits, the first to fifth switches, and the control circuit. Therefore, for example, even in a vehicle with a high voltage specification, a high voltage supplied from one type of battery power source can be converted into a low voltage by the first power supply circuit and supplied to a plurality of control units. Since it is not necessary to provide a circuit for voltage conversion or the like, it is possible to reduce the size and weight of the entire power supply device including the battery power supply, the control unit, etc., and simplify the structure to reduce the cost. When the first power supply circuit is abnormal, the second power supply circuit
The main power supply circuit can supply power to the main control unit, etc., and if a large surge voltage occurs on the battery power supply side, each transistor can shut off the control unit from the surge voltage for protection and improve reliability. You can

According to the second aspect of the invention, the sixth switch which is turned on and off by the control circuit is connected between the battery power source and the load. When the high-voltage wiring extending to the load and the low-voltage wiring extending from the power supply circuit to the control unit are short-circuited, the sixth switch can be turned off to interrupt the high-voltage wiring, and the high voltage on the battery power source side It is possible to reliably prevent the control unit from going around to the control unit side via the short-circuited portion, and it is possible to further improve reliability.

Further, according to the invention of claim 3, since each switch is composed of a transistor, the switch can be made smaller and lighter, and its operating characteristics and the like can be appropriately set as required.

Further, according to the invention of claim 4, since each switch is constituted by a relay, the structure of the switch can be simplified and the cost can be reduced.

Further, according to the invention of claim 5, since the resistor is provided between the battery power source and the input side of the second power circuit, for example, the input of the second power circuit is input from the battery power side. The surge voltage applied to the side can be suppressed to a small amount by the voltage drop due to the resistance, and the second power supply circuit can be protected from the surge voltage and the like.

Further, according to the invention of claim 6, a fail signal is sent to the first control unit when an abnormal voltage is input to the voltage monitoring terminal from the output side of the first power supply circuit. Since the fail signal terminal for outputting is provided, for example, when the first power supply circuit is abnormal,
The second power supply circuit can operate the first control unit in a power saving state or the like. Therefore, for example, the second power supply circuit can be configured by a backup power supply circuit that supplies less power than the first power supply circuit, and the reliability can be improved while suppressing cost increase.

Further, according to the invention of claim 7, the control circuit, when the input voltage to the voltage monitoring terminal becomes abnormal,
Since the first to third switches are switched from ON to OFF and the fourth and fifth switches are switched from OFF to ON, when the first power supply circuit is abnormal, this power supply circuit is connected to the battery power supply and each control unit. It can be cut off from both units and grounded to the ground. For example, a surge voltage or the like generated on the battery power supply side can be surely cut off to the control unit, and power can be supplied to the control unit from the second power supply circuit.

Further, according to the invention of claim 8, the control circuit is configured to switch the sixth switch from ON to OFF when the input voltage to the voltage monitoring terminal is higher than the normal voltage. Even if the first switch is turned off, if the output voltage of the first power supply circuit is higher than the normal voltage, it is determined that the high voltage of the battery power supply side has spilled over to the output side of the first power supply circuit. The sixth switch is OF
It can be switched to F, and this high voltage can be prevented from being applied to the control unit.

Further, according to the invention of claim 9, since the active clamp circuit is connected to the first switch, when an abnormal voltage such as a surge voltage occurs on the battery power source side, for example, this abnormal voltage is generated. Can be blocked by the active clamp circuit from being applied to the first power supply circuit side via the first switch, and the power supply circuit, the control unit and the like can be protected.

Further, according to the invention of claim 10, since the control circuit is provided with the control signal circuit which is held in a floating state with respect to the ground, the control signal connected to the first switch is provided. The working circuit can be kept floating with respect to ground. This allows
For example, even when a large surge voltage or the like is applied to the first switch from the battery power source side, it is possible to prevent a large voltage from being applied between the terminals of the switch and protect the first switch.

Further, according to the invention of claim 11, the first
The saturation current value of the switch is set to a value that is larger than the sum of the current values supplied to the first and second control units and that is smaller than the current value corresponding to the abnormal voltage on the battery power supply side. Therefore, for example, even when a large abnormal voltage is applied to the first switch from the battery power supply side, the value of the current flowing through the first switch can be suppressed to be equal to or lower than the saturation current value, and the first power supply connected to the output side thereof can be suppressed. circuit,
It is possible to protect the first and second control units and the like.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a vehicle power supply device according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relation between a drain-source electrode voltage and a drain current of the transistor used in the first embodiment.

FIG. 3 is an overall configuration diagram showing a vehicle power supply device according to a second embodiment of the present invention.

FIG. 4 is a circuit configuration diagram showing an active clamp circuit of a vehicle power supply device according to a third embodiment of the present invention.

FIG. 5 is a circuit configuration diagram showing a charge pump circuit of a vehicle power supply device according to a fourth embodiment of the present invention.

FIG. 6 is a circuit configuration diagram showing a part of a vehicle power supply device according to a modification of the present invention.

[Explanation of symbols]

1 Battery Power Supply 2 Ground 3, 21 Power Supply Units 3A, 3B, 3C, 3D, 21A, 21B, 21C, 2
1D, 21E, 21F connection terminal 4 1st power supply circuit 4A input terminal 4B output terminal 4C operation control terminal 5 2nd power supply circuit 5A input terminal 5B output terminal 5C power supply terminal 6 resistors 7, 8, 9, 10, 11, 23 transistor (switch) 12, 24, 31, 41 control circuit 12A, 24A power supply terminal 12B, 24B power supply circuit control terminal 12C, 12D, 12E, 12F, 12G, 24C, 2
4D, 24E, 24F, 24G, 24H, 31A, 41
A Transistor control terminal 12H, 24J Voltage monitoring terminal 12J, 24K Fail signal terminal 13 First control unit 14, 16 Low voltage wiring 15 Second control unit 22 High voltage wiring 25, 26 Load 32 Active clamp circuit 42 Charge pump Circuit (control signal circuit)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5G003 BA01 DA02 DA17 DA18 FA04                 5G053 AA09 BA04 CA02 CA03 EB02                       EB08 EC03 FA05                 5H730 AA11 AA16 AA20 AS05 BB11                       BB57 BB88 BB98 DD04 DD26                       EE65 EE73 FG01 XC07

Claims (11)

[Claims] 1. A first power supply circuit and a second power supply circuit that are supplied with power from a battery power supply, wherein the first power supply circuit has a first switch between its input side and the battery power supply. And connecting a second switch between the output side of the first power supply circuit and the first control unit, and between the output side of the first power supply circuit and the second control unit. A third switch is connected to the fourth power switch, and a fourth switch is connected between the output side and the ground side of the first power supply circuit, and the second power supply circuit connects its input side to the battery power supply. Then, a fifth switch is connected between the output side of the second power supply circuit and the first control unit, and power is supplied from the second power supply circuit and an abnormality occurs in the first power supply circuit. Sometimes the first control circuit is stopped, The first to fifth switches are turned on,
A control circuit is provided that is turned off to supply power from the second power supply circuit, and the output side of the first power supply circuit is connected to the control circuit for monitoring the state of the output voltage of the first power supply circuit. A vehicle power supply device configured to provide a voltage monitoring terminal. 2. A load that is supplied from the battery power source and is controlled by the control unit is provided in at least one of the first and second control units, and a load is provided between the battery power source and the load. The vehicle power supply device according to claim 1, wherein a sixth switch that is turned on and off by the control circuit is connected. 3. The vehicle power supply device according to claim 1, wherein each of the switches comprises a transistor. 4. The vehicle power supply device according to claim 1, wherein each of the switches comprises a relay. 5. A resistor is provided between the battery power supply and the input side of the second power supply circuit.
Alternatively, the vehicle power supply device according to item 4. 6. A fail signal terminal for outputting a fail signal to the first control unit when an abnormal voltage is input to the voltage monitoring terminal from the output side of the first power supply circuit, in the control circuit. Claim 1, which is provided with
The power supply device for vehicle according to 2, 3, 4 or 5. 7. The control circuit holds the first to third switches ON while a normal voltage is input to the voltage monitoring terminal from the output side of the first power supply circuit, and When the fourth and fifth switches are kept OFF and the input voltage to the voltage monitoring terminal becomes abnormal, the first to third switches are turned OFF and the fourth and fifth switches are turned OFF. 7. A structure for switching a switch to ON, 1, 2, 3, 4, 5 or 6.
The vehicle power supply device according to. 8. The control circuit holds the sixth switch ON while a normal voltage is input to the voltage monitoring terminal from the output side of the first power supply circuit, 8. The vehicle power supply device according to claim 2, wherein the sixth switch is turned off when the input voltage to the input voltage is higher than a normal voltage. 9. The active switch circuit is connected to the first switch to shut off the first power supply circuit side from an abnormal voltage when an abnormal voltage is generated on the battery power supply side. 1, 2, 3, 4, 5,
The vehicle power supply device according to 6, 7, or 8. 10. The control circuit is provided with a control signal circuit held in a floating state with respect to ground, and the control signal circuit outputs a control signal for turning on and off the first switch. Claims 1, 2,
The power supply device for vehicle according to 3, 4, 5, 6, 7 or 8. 11. A value of a saturation current flowing through the first switch is larger than a sum of current values that are normally applied to the first and second control units, and is generated on the battery power source side. 2. A configuration in which a value smaller than the current value corresponding to the abnormal voltage is set.
The power supply device for a vehicle according to 3, 4, 5, 6, 7, 8, 9, or 10.