JP4140537B2 - Vehicle power supply system - Google Patents

Description

  The present invention relates to a vehicular power supply system, and more particularly to a vehicular power supply system having an abnormal current blocking function.

Generally, a power supply system for vehicles and the like requires a fuse element for cutting off a current path when an abnormal current such as an overcurrent occurs. A general fuse element is constituted by a conductive element that melts as an overcurrent passes. Further, for example, Patent Document 1 discloses a technique in which a power MOS (Metal Oxide Semiconductor) -FET (Field Effect Transistor) is used as a fuse in order to cut off an intermittent short-circuit current in which a general fuse element is difficult to blow. Has been.
Japanese Patent Laid-Open No. 11-136846 JP 2002-261594 A JP 2002-38984 A

  However, in an automobile which is a typical example of a vehicle, electric loads are classified into a plurality of systems having different operation timings. For example, there are a load group that operates in response to turning on an accessory switch (so-called ACC switch) and a load group that operates in response to turning on an engine start switch (so-called IGCD switch). In addition, there are a load group that receives the supply voltage from the battery as it is as a power supply voltage, a load group that receives a power supply voltage obtained by boosting the battery voltage by a booster circuit, and the like.

  Since load currents differ among the plurality of load systems, it is desirable to use wiring with a harness diameter that matches the load current rating for each of these load systems in order to efficiently arrange the power supply wiring.

  Therefore, in such a power supply system, since a plurality of power supply lines are branched from the common power supply device, a fuse element may be provided at the root of the power supply path to each load inside the power supply device. Necessary.

  In particular, the power supply device that converts the output voltage of the battery to generate the power supply voltage of the load is preferably disposed close to the battery in order to shorten the low-voltage wiring portion and reduce power loss. In general, since the battery is stored in a place where it is difficult to touch a human hand in consideration of safety, the power supply apparatus tends to have a layout arrangement that is difficult to maintain. For this reason, when the fuse element is provided inside the power supply device, it is necessary to consider a design that improves its maintainability.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a vehicle that supplies power from a common power supply apparatus to a plurality of load systems using independent power supply wirings. It is to provide a fuse element arrangement excellent in maintenance in a power supply system for industrial use.

  The vehicle power supply system according to the present invention includes a plurality of load systems, a power supply device, and a plurality of power wirings. The power supply device is provided to supply power to a plurality of load systems. The plurality of power wirings respectively connect the power supply device and the plurality of load systems. The power supply device includes a plurality of power semiconductor switch elements connected in series to each of the plurality of power wires, and a plurality of abnormal current detection units provided corresponding to the plurality of power semiconductor switch elements, respectively. A plurality of holding circuits, a plurality of forced cutoff circuits, and a plurality of forced cutoff release circuits. Each of the plurality of abnormal current detectors detects an abnormal current of the corresponding power semiconductor switch element, and each of the plurality of holding circuits continuously holds the held contents until a reset input is given, In response to the reset input, the held contents are initialized to the first state. Each of the plurality of forced cutoff release circuits transitions the held content from the first state to the second state when an abnormal current is detected by the corresponding abnormal current detection unit. Each of the plurality of forced cutoff circuits forcibly shuts down the corresponding power semiconductor switch element and responds to an input from the outside of the power supply device when the corresponding holding circuit holds the second state. Then, the corresponding power semiconductor switch element is made conductive, and a reset input is given to the corresponding holding circuit.

  Preferably, one of the plurality of load systems includes a load that operates in response to an operation of the vehicle driver, and an external input corresponding to the load is in response to an operation of the vehicle driver. It is an electrical signal that is generated.

  More preferably, the operation of the driver of the vehicle is an ON operation of an ignition switch.

  More preferably, the operation of the driver of the vehicle is an on operation of an accessory switch.

  Preferably, the power supply device generates power to a plurality of load systems using power supplied from the battery as a source, and one of the plurality of load systems operates by constantly receiving power supply from the battery. An input from the outside including the load and corresponding to the load is given by an operation of grounding a predetermined electrical terminal.

  Alternatively, preferably, the power supply device generates power to a plurality of load systems using power supplied from the battery as a source, and the power supply device is disposed in proximity to the battery.

  In the vehicle power supply system according to the present invention, the power wiring is provided separately for each of the plurality of load systems, and each power wiring is efficiently arranged as a harness diameter corresponding to the load current. A semiconductor switch element provided inside the common power conversion device can be used as a fuse element that can be returned from a cut-off state to a conduction state by an input from the outside of the power conversion device.

  Therefore, a fuse element that does not require component replacement can be realized, and a configuration with excellent maintainability can be obtained. In particular, even when the power supply device is arranged in an environment with poor maintenance workability, serviceability is not deteriorated.

  In addition, the semiconductor switch element corresponding to the load group that operates in response to the driver's operation is configured to return to the initial conductive state in response to the electrical signal generated in response to the operation. An initial load current path can be reliably formed at the start of operation of the load group. In particular, the above-described configuration can be realized by using an ignition switch signal (so-called IGCT signal) or an accessory switch signal (so-called ACC signal) generally used in automobiles.

  Furthermore, it is necessary to replace parts by adopting a configuration in which the semiconductor switch element corresponding to the load group that operates by receiving a current supply from the battery is restored to the initial conductive state by an operation of grounding a predetermined electrical terminal. The work equivalent to the replacement of the fuse element can be performed with a simple operation and maintenance can be improved.

  In particular, by arranging the power supply device close to the battery stored in a part that is difficult to touch so that there is little risk of electric shock, the low voltage wiring part can be shortened to reduce power loss. Although it is possible, in such a case, there is a great advantage in realizing a fuse element that does not require replacement of parts and improving maintainability.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or an equivalent part below, and the description shall not be repeated in principle.

  FIG. 1 is a schematic block diagram showing an overall configuration of a vehicle power supply system 10 according to an embodiment of the present invention. As will become apparent from the following description, the vehicle power supply system 10 is typically a vehicle power supply system premised on being mounted on an automobile.

  Referring to FIG. 1, a vehicle power supply system 10 according to the present invention supplies power to a plurality of load systems 20a to 20d. The vehicle power supply system 10 includes a power supply device 30 and power wirings 35a to 30d provided corresponding to the load systems 20a to 20d, respectively.

  Power supply device 30 includes an input terminal 32 that receives battery voltage VB from battery 50, input terminals 36 to 38, a booster circuit 40, and output terminals 45a to 45d. The booster circuit 40 boosts the battery voltage VB input to the input terminal 32 to generate a boosted voltage VC. The battery voltage VB is output from the output terminal 45a. On the other hand, a boosted voltage VC boosted for the booster circuit is output from the output terminals 45b to 45d.

  The power supply wirings 35a to 35d connect between the output terminals 45a to 45d of the power supply device 30 and the load systems 20a to 20d, respectively. The input terminals 36 to 38 are terminals capable of electrical input such as voltage signals. The input terminal 36 is supplied with an operation signal for canceling the forced cutoff state, which will be described in detail later, and the input terminal 37 is supplied with an accessory activation switch signal, so-called ACC signal, in response to the driver's switch operation. . Similarly, an ignition switch signal, so-called IGCT signal, is input to the input terminal 38 in response to the driver's switch operation.

  The ACC signal and the IGCT signal are generated by a signal generation circuit (not shown) in response to the driver's switch operation.

  The load system 20a is composed of an electric load group that is constantly supplied with the battery voltage VB, and the load system 20b is composed of an electric load group that is always supplied with the boosted voltage VC. On the other hand, the load system 20c is configured by an electrical load group that operates in response to the IGCT signal, and the load system 20d is configured by an electrical load group that operates in response to the ACC signal.

  FIG. 2 is a diagram for explaining in detail the configuration of the power supply device 30 shown in FIG. 1.

  Referring to FIG. 2, power supply device 30 includes control circuits 60, 62, 64, diodes 90, 91, power, in addition to input terminals 32, 36-38, booster circuit 40, and output terminals 45a-45d. Semiconductor power switch element 95, power semiconductor switch elements 100a to 100d provided corresponding to each of load systems 20a to 20d, and forced cutoff release circuit 110. In this embodiment, power semiconductor switch elements 100a to 100d are formed of p-type MOS-FETs. In the following, each power semiconductor switch element is also simply referred to as “semiconductor switch element”.

  Corresponding to the semiconductor switch element 100a, an abnormal current detection circuit 102a, a self-holding circuit 104a, and a forced cutoff circuit 106a are provided, and a gate resistor 108a is connected to the gate thereof. Similarly, an abnormal current detection circuit 102b, a self-holding circuit 104b, and a forced cutoff circuit 106b are provided corresponding to the semiconductor switch element 100b, and a gate resistor 108b is connected to the gate thereof.

  The semiconductor switch element 100c is provided with an abnormal current detection circuit 102c, a self-holding circuit 104c, and a forced cutoff circuit 106c, and a gate resistor 108c is connected to the gate thereof. Further, an abnormal current detection circuit 102d, a self-holding circuit 104d, and a forced cutoff circuit 106d are provided corresponding to the semiconductor switch element 100d, and a gate resistor 108d is connected to the gate thereof.

  The diode 90 is provided between the input terminal 32 and the power supply line 80a corresponding to the load system 20a (+ B system), and is connected with the direction from the input terminal 32 toward the power line 80a as the forward direction. The power line 80a is electrically connected to the output terminal 45a via the semiconductor switch element 100a.

  The diode 91 is provided between the input terminal 32 and the power supply line 80b corresponding to the load system 20b (boost system), and is connected with the direction from the input terminal 32 toward the power line 80b as the forward direction. The power line 80b is electrically connected to the output terminal 45b via the semiconductor switch element 100b.

  The booster circuit 40 operates in response to an operation instruction from the control circuit 60. During operation, the booster circuit 40 boosts the battery voltage VB input to the input terminal 32 and outputs the boosted voltage VC to its own output node.

  The semiconductor switch element 95 is electrically connected between the output node of the booster circuit 40 and the power line 80b, and is turned on / off in response to an instruction from the control circuit 60. The control circuit 60 controls operations of the booster circuit 40 and the semiconductor switch element 95.

  By turning on the semiconductor switch element 95 by the control circuit 60, the boosted voltage VC can be supplied to the power supply line 80b. On the other hand, when the semiconductor switch element 95 is turned off, the battery voltage VB is supplied to the power supply line 80b. That is, the supply voltage to the load system 20b can be switched between the battery voltage VB and the boosted voltage VC by turning on and off the semiconductor switch element 95.

  The power line 80c corresponding to the load system 20c (IGCT system) is connected to the output node of the booster circuit 40, and is further connected to the output terminal 45c via the semiconductor switch element 100c. Similarly, the power line 80d corresponding to the load system 20d (ACC system) is connected to the output node of the booster circuit 40 and is connected to the output terminal 45d via the semiconductor switch element 100d. The output terminals 45a to 45d are connected to the power wirings 35a to 35d shown in FIG. Therefore, the semiconductor switch elements 100 a to 100 d are connected in series to the power wirings 35 a to 35 d inside the power supply device 30.

  Semiconductor switch elements 100a to 100d operate as semiconductor fuses in the vehicle power supply system of the present invention. Since the operation of each of the semiconductor switch elements 100a to 100d is the same, the operation of the semiconductor switch element 100a will be representatively described below.

  The switching element module 150a in which the semiconductor switching element 100a and the auxiliary current group abnormal current detection circuit 102a, the self-holding circuit 104a, the forced cutoff circuit 106a, and the gate resistance 108a are integrally stored in the same package is used as a semiconductor fuse. It may be used. Similarly, as a semiconductor fuse corresponding to the load systems 20b to 20d, a switch element in which a semiconductor switch element and an auxiliary circuit group (an abnormal current detection circuit, a self-holding circuit, and a forced cutoff circuit) are integrally stored in the same package. Modules 150b-150d can be used.

  The abnormal current detection circuit 102a provided corresponding to the semiconductor switch element 100a detects the abnormal current by channel temperature rise detection which is a known technique. The type of the abnormal current detection circuit 102a is not particularly limited. For example, the abnormal current detection circuit 102a may be configured to detect an abnormal current based on a measurement current using a Hall element or a shunt resistor.

  The self-holding circuit 104a operates so as to hold the self-holding content. The content held by the self-holding circuit 104a is, for example, a 1-bit signal set to either a logic low level or a logic high level.

  The content held by the self-holding circuit 104a is initially set to a logic low level, and when an abnormal current of the semiconductor switch element 100a is detected in the abnormal current detection circuit 102a, the abnormal current detection is triggered as a low level. Transition from high to low. Further, the held content once transitioned is held at a high level until a reset input for resetting the held content of the self-holding circuit 104a to the initial state is given.

  The forced cutoff circuit 106a outputs an electrical input for forcibly turning off the semiconductor switch element 100a to its gate when the content held by the self-holding circuit 104a is at a high level. On the other hand, when the holding state of the self-holding circuit 104a is at a low level, the forced cutoff circuit 106a does not output the above electrical output, and the semiconductor switch element 100a is held in the on state.

  In this way, the semiconductor switch element 100a that is initially in the on state maintains the on state until an abnormal current is detected by the abnormal current detection circuit 102a. Further, when the abnormal current is detected, the forced cutoff circuit 106a is forcibly turned off, and the forced off state is maintained thereafter by the holding function of the self-holding circuit 104a.

  Similarly, each of the semiconductor switch elements 100b to 100d is initially turned on, and is kept on until an abnormal current is detected by the corresponding abnormal current detection circuit 102b to 102d. Later, it is forcibly turned off, and the turn-off state is maintained thereafter.

  Next, a forced-off state canceling mechanism for each semiconductor switch element that has been forcibly turned off will be described. First, the configuration and operation of the forced cutoff release circuit 110 corresponding to the load systems 20a and 20b to which power is constantly supplied will be described.

  The forced cutoff release circuit 110 includes a pnp transistor 112 and resistance elements 114 to 117. The emitter of the pnp transistor 112 is connected to the output node of the booster circuit 40. The collector of the pnp transistor 112 is connected to the gates of the semiconductor switch elements 100a and 100b via the gate resistors 108a and 108b, and is grounded via the resistor element 114.

  The resistance element 115 is connected between the output node of the booster circuit 40 and the base of the pnp transistor 112 and functions as a bias resistor. Resistance elements 116 and 117 are connected in series between the gate of the pnp transistor and input terminal 36.

  The input terminal 36 is brought into an electrically floating state by providing a cap or the like at normal times. At this time, the pnp transistor 112 is turned off, and a ground voltage is applied to the abnormal current detection circuit 102a, the self-holding circuit 104a, and the forced cutoff circuit 106a. Similarly, the ground voltage is also applied to the abnormal current detection circuit 102b, the self-holding circuit 104b, and the forced cutoff circuit 106b.

  On the other hand, when the input terminal 36 is grounded by a contact operation with the body or the like, the pnp transistor 112 is turned on. At this time, the abnormal current detection circuits 102a and 102b and the forced cutoff circuits 106a and 106b are supplied with a high voltage corresponding to the boosted voltage VC instead of the ground voltage. The high voltage becomes a reset input to the abnormal current detection circuits 102a and 102b, the self-holding circuits 104a and 104b, and the forced cutoff circuits 106a and 106b.

  In response to this reset input, the contents held in the self-holding circuits 104a and 104b are initialized to a low level. Thereafter, the pnp transistor 112 is turned off again by bringing the input terminal 36 into an electrically floating state, and the abnormal current detection circuits 102a and 102b, the self-holding circuits 104a and 104b, and the forced cutoff circuits 106a and 106b are assisted. The reset input to the circuit group is canceled. Further, the gate voltage of the semiconductor switch element 100a also returns to the ground voltage. Thereby, thereafter, the semiconductor switch elements 100a and 100b are returned to the initial turn-on state, and the turn-on state is maintained by the reset self-holding circuits 104a and 104b.

  That is, the semiconductor switch elements 100a and 100b corresponding to the load systems 20a and 20b to which electric power is constantly supplied maintain the off state so as to cut off the current path when an abnormal current is generated, thereby exhibiting a fuse function. Furthermore, the grounding operation of the input terminal 36 from the outside of the power supply device 30 allows the semiconductor switch elements 100a and 100b to return to the turn-on state, thereby realizing an operation equivalent to replacement of the blown fuse element.

  The input terminal 36 can be grounded, for example, by providing a lead wire from the power supply device 30 to the vicinity of the grounding part, and providing an insulating cap, and removing the cap only at the time of the disconnection release operation. It can be configured.

  On the other hand, the forced cutoff state corresponding to the load systems 20c and 20d operating in synchronization with the IGCT signal and the ACC signal, respectively, is released as follows.

  In response to the input of the IGCT signal to the input terminal 37, the control circuit 62 generates a control signal SRc similar to the reset input (high voltage) generated when the pnp transistor 112 is turned on. Control signal SRc from control circuit 62 is applied as a reset input to abnormal current detection circuit 102c, self-holding circuit 104c, and forced cutoff circuit 106c.

  Similarly, the control circuit 64 generates a control signal SRd similar to the control signal SRc in response to the input of the ACC signal to the input terminal 38. Control signal SRd from control circuit 64 is applied as a reset input to abnormal current detection circuit 102d, self-holding circuit 104d, and forced cutoff circuit 106d.

  Therefore, the semiconductor switch element 100c is returned to the on state by the control signal SRc from the control circuit 62 in response to the IGCT signal, and thereafter the turn-on state is maintained by the reset self-holding circuit 104c. Similarly, the semiconductor switch element 100d is returned to the on state by the control signal SRd from the control circuit 64 in response to the ACC signal, and thereafter the turn-on state is maintained by the reset self-holding circuit 104d.

  That is, the control circuits 62 and 64 constitute “forced cutoff release circuits” respectively corresponding to the IGCT load system 20c and the ACC load system 20d.

  As described above, the semiconductor switch elements 100c and 100d corresponding to the load systems 20c and 20d that operate in synchronization with the IGCT signal and the ACC signal, respectively, maintain the OFF state so as to cut off the current path when the abnormal current is generated, and have the fuse function. Demonstrate. Furthermore, the semiconductor switch elements 100c and 100d are returned to the turn-on state by the input of electrical signals (IGCT signal and ACC signal) to the input terminals 36 and 37 from the outside of the power supply device 30, and the fusing fuse element is replaced. An equivalent operation can be realized.

  As a result, at the start of operation of the load systems 20c and 20d that operate in synchronization with the IGCT signal and the ACC signal, the corresponding semiconductor switch elements 100c and 100d are returned to the ON state, thereby reliably forming an initial load current path. be able to.

  As described above, in the power supply system according to the present invention, in a configuration in which power wiring is provided separately for each load system that requires constant power supply and for each load system that operates in synchronization with the ACC signal or IGCT signal, A semiconductor switch element provided in the device can be used as a fuse element that can be returned from a cut-off state to a conductive state by an input from the outside of the power conversion device.

  As a result, a fuse element that does not require component replacement can be realized, and a configuration with excellent maintainability can be obtained. In particular, even when the power supply device is arranged in an environment with poor maintenance workability, serviceability is not deteriorated.

  FIG. 3 is a block diagram illustrating an example of mounting the vehicle power supply system according to the present invention in an automobile.

  Referring to FIG. 3, an automobile 200 equipped with a vehicle power supply system according to the present invention includes a battery 50, a power output device 230, a differential gear 240, front wheels 250L and 250R, rear wheels 260L and 260R, Seats 270L and 270R, a rear seat 280, a dashboard 290, and a key switch 295 are provided.

  The battery 50 is stored, for example, in an engine room with a waterproof cover or the like to prevent leakage or the like, and is stored in a portion that is less likely to be touched by a person with a low risk of electric shock. The power supply device 30 generates power supplied to a plurality of load systems in the automobile 200 using power supplied from the battery 50 as a source. Power is supplied from the power supply device 30 to various electric loads in the automobile 200 through the plurality of power supply wires 35a to 35d shown in FIG. Preferably, the power supply device 30 is disposed close to the battery 50 in order to shorten the low voltage wiring portion and reduce power loss.

  In the vehicular power supply system according to the present invention, even when the power supply device 30 is disposed close to the battery 50 and inferior in maintainability, the ACC signal and IGCT generated in accordance with the operation of the key switch 295 by the driver. In synchronization with the signal, the semiconductor switch elements (100c and 100d in FIG. 2) used as fuse elements can be returned from the cut-off state to the conductive state.

  Further, the input terminal 36 of the power supply device 30 is drawn out by a lead wire 297 or the like, and an insulating cover 298 is provided on a conductor portion of the input terminal 36. Thus, when the semiconductor switch elements 100a and 100b are shut off, the semiconductor switch element (100c, 100c in FIG. 2) is used by a simple operation of removing the insulating cover 298 and grounding the input terminal 36 by contact with the body or the like. 100d) can be returned from the cut-off state to the conductive state.

  As described above, the semiconductor fuse element provided in the power supply device 30 disposed in a poorly maintainable part is blown by the operation of the key switch 295 or the input terminal 36 drawn to the vicinity of the body. Since the operation equivalent to the replacement operation of the fuse element can be performed, the maintainability can be improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic block diagram showing the overall configuration of a vehicle power supply system according to an embodiment of the present invention. It is a figure explaining the structure of the electric power supply apparatus shown in FIG. 1 in detail. It is a block diagram explaining the example of mounting to the motor vehicle the power supply system for vehicles of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Power supply system for vehicles, 20a-20d Load system, 30 Power supply device, 32 Input terminal (battery voltage), 35a-35d Power wiring, 36-38 input terminal, 40 Booster circuit, 45a-45d Output terminal (Power supply device) ), 50 battery, 60, 62, 64 control circuit, 80a to 80d power line (inside power supply device), 90 diode, 100a to 100d power semiconductor switch element (semiconductor fuse), 102a to 102d abnormal current detection circuit, 104a -104d Self-holding circuit, 106a-106d Forced shut-off circuit, 108a-108d Gate resistance, 110 Forced shut-off release circuit, 150a-105d Switch element module, 200 Automobile, 295 Key switch, 297 Lead wire, 298 Insulation cover, VB battery Pressure, VC boost voltage.

Claims (5)

Multiple load systems;
A power supply device for supplying power to the plurality of load systems;
A plurality of power wirings for connecting between the power supply device and the plurality of load systems, respectively,
The power supply device
A plurality of power semiconductor switch elements connected in series to each of the plurality of power wirings;
A plurality of abnormal current detectors, a plurality of holding circuits, a plurality of forced cutoff circuits, and a plurality of forced cutoff release circuits, which are provided corresponding to the plurality of power semiconductor switch elements ,
Including an electric terminal having a conductor portion that is covered by a removable insulating cover and drawn out to the vicinity of the vehicle body,
Each of the plurality of abnormal current detectors detects an abnormal current of the corresponding power semiconductor switch element,
Each of the plurality of holding circuits continuously holds the held content until a reset input is given, and initializes the held content to the first state in response to the reset input, and corresponds When the abnormal current is detected by the abnormal current detector, the held content is transitioned from the first state to the second state,
Each of the plurality of forced cutoff circuits forcibly shuts off the corresponding power semiconductor switch element when the corresponding holding circuit holds the second state,
Each of the plurality of forced cutoff release circuits conducts the corresponding power semiconductor switch element in response to an input from the outside of the power supply device, and outputs the reset input to the corresponding holding circuit. Give ,
The vehicle power supply system , wherein the external input is given by an operation of grounding the electric terminal from which the insulating cover is removed . The first load system of the plurality of load systems includes a first load that operates by constantly receiving power supply from the battery ,
The external input corresponding to the first load is given by an operation of grounding the electrical terminal,
A second load system of the plurality of load systems includes a second load that operates in response to an operation of a driver of the vehicle,
The vehicle power supply system according to claim 1, wherein the external input corresponding to the second load is an electrical signal generated in response to an operation of a driver of the vehicle.   The vehicle power supply system according to claim 2, wherein the operation of the driver of the vehicle is an ON operation of an ignition switch.   The vehicle power supply system according to claim 2, wherein the operation of the driver of the vehicle is an on operation of an accessory switch. The power supply device generates power to the plurality of load systems using power supplied from a battery as a source,
The power supply system for a vehicle according to any one of claims 1 to 4 , wherein the power supply device is disposed in proximity to the battery.

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