JP2023059025A - Power supply control device - Google Patents

Abstract

To provide a power supply control device having an increased protection function at time of occurrence of abnormality.SOLUTION: Provided is a power supply control device 100 connected to a power supply line 3 that supplies current from a power supply to a load circuit 2, including: a semiconductor switch 20 connected to the power supply line 3; a power supply fuse 10 connected to the power supply line 3 on the upstream side of the semiconductor switch 20; and an abnormality detector 30 that detects an abnormal state. When the abnormality detector 30 detects an abnormal state, the power supply fuse 10 interrupts the current, and when the abnormality detector 30 does not detect the abnormal state, the semiconductor switch 20 switches on/off of the current.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power control device.

2. Description of the Related Art Conventionally, a power supply controller used in a power supply circuit for an in-vehicle electronic control device, which has a protection function against overcurrent and overvoltage, is known. For example, the power supply controller described in Patent Document 1 has a switching control circuit that forms a switching regulator together with an FET, and a series control circuit that forms a series regulator together with a transistor, and is inserted between the smoothing circuit and the transistor. Based on the detection result of the current detection circuit that detects the voltage across the current detection resistor and the detection result of the temperature detection circuit that detects the temperature of the FET, overcurrent, overvoltage, etc. are detected, and the FET and transistor are detected. Turn off (Patent Document 1).

JP 2004-147391 A

However, the above-described power supply controller may not be able to cut off power supply if a semiconductor switch such as an FET cannot be switched on and off due to some abnormality, and has a problem that the protection function is insufficient.

The problem to be solved by the present invention is to provide a power supply control device with an enhanced protection function when an abnormality occurs.

The present invention comprises a semiconductor switch connected to a power supply line, a power supply fuse connected to the power supply line upstream of the semiconductor switch, and an abnormality detector for detecting an abnormality, wherein the abnormality detector detects an abnormality. The power supply fuse cuts off the current when it is detected, and the semiconductor switch turns the current on and off when the abnormality detector does not detect the abnormality, thereby solving the above problem.

The present invention can enhance the protection function when an abnormality occurs.

FIG. 1 is a block diagram of a power control device according to an embodiment of the invention. FIG. 2 is a cross-sectional view of the power control device according to the embodiment of the invention. FIG. 3 is a block diagram of a reference example of a power control device. FIG. 4 is a block diagram of a reference example of a power control device.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a power control device according to an embodiment of the invention. A power supply control device according to the present embodiment is a device that controls a power supply system for supplying power from a battery to a load circuit. The power supply system is provided in the vehicle, and supplies power from the vehicle battery to the auxiliary devices of the vehicle display. A power supply control device is applied to a drive system or the like that drives a load such as a motor.

As shown in FIG. 1, the power system includes a battery 1, a load circuit 2, a power line 3, and a power control device 100. A battery 1 is a vehicle battery and a power source for operating a load circuit. The battery 1 is, for example, a 12V battery that supplies electric power to auxiliaries or the like, or a large-capacity battery that is mounted on an electric vehicle or a hybrid vehicle. The load circuit 2 includes a load such as a display and an air conditioner, a control circuit for controlling the load, and the like. The power line 3 is a power line that electrically connects the battery 1 and the load circuit 2 .

The power supply control device 100 has a function of protecting the load circuit when an abnormality such as overcurrent or overvoltage occurs, and has a function of switching between electrical continuity and cutoff between the battery 1 and the load circuit 2 . The power supply control device 100 also has a function of interrupting current flowing from the battery 1 to the load circuit 2 when an abnormality occurs. The power control device 100 includes a power fuse 10 , a semiconductor switch 20 , an abnormality detector 30 , a heating element 40 , a protection circuit 50 , a heating element control switch 60 and a control circuit 70 .

The power fuse 10 is connected to the power supply line 3 on the upstream side of the semiconductor switch 20 , and is part of wiring for electrically conducting between the battery 1 and the semiconductor switch 20 . The power fuse 10 is connected between the positive terminal of the battery 1 and the high potential side terminal of the semiconductor switch 20 . The power fuse 10 is melted by receiving heat from the outside, thereby physically disconnecting the wiring and cutting off the current flowing from the battery 1 to the load circuit 2 . When the abnormality detector 30 detects an abnormal state, the power fuse 10 cuts off the current.

The semiconductor switch 20 is a semiconductor component composed of a transistor such as an FET, and is connected to the power line 3 between the power fuse 10 and the load circuit 2 . The semiconductor switch 20 has a high potential side terminal, a low potential side terminal, and a control terminal. When the semiconductor switch 20 is composed of an FET, the drain terminal corresponds to the high potential side terminal, the source terminal corresponds to the low potential side terminal, and the gate terminal corresponds to the control terminal. A high potential side terminal of the semiconductor switch 20 is connected to the power supply fuse 10 via the power supply line 3, a low potential side terminal of the semiconductor switch 20 is connected to the load circuit 2 via the power supply line 3, and a control terminal of the semiconductor switch 20 is connected. are connected to the control circuit 70 via signal lines. The control circuit 70 is a circuit that switches the semiconductor switch 20 on and off. The semiconductor switch 20 switches between on and off according to a control signal sent from the control circuit 70 . When the abnormality detector 30 does not detect an abnormal state (when the state is normal), the semiconductor switch 20 switches on and off the current flowing through the power supply line 3 .

The abnormality detector 30 detects at least one abnormal state among overcurrent, overvoltage, high temperature, outgassing, and abnormality of the semiconductor switch 20 . Overcurrent is a state in which an excessive current flows through the power supply line 3 , and overvoltage is a state in which an excessive voltage is applied to the semiconductor switch 20 . The abnormality detector 30 detects the current flowing through the semiconductor switch 20, and determines that there is an abnormal state due to overcurrent when the detected current exceeds the rated current. Further, the abnormality detector 30 may detect the voltage applied to the semiconductor switch 20 and determine whether or not the voltage is overvoltage based on the detected voltage.

An abnormality of the semiconductor switch 20 is an increase in voltage drop of the semiconductor switch 20, an open/close failure of the semiconductor switch 20, or the like. Since the semiconductor switch 20 switches on and off by electrical operation, an abnormality occurs due to an accidental failure or surge, and the occurrence rate of abnormality is higher than that of a switch that switches on and off by mechanical operation such as a relay. If the semiconductor switch 20 has a self-diagnosis function, the abnormality detector 30 detects an abnormality of the semiconductor switch 20 from the diagnosis result of the semiconductor switch 20 .

Further, the abnormality detector 30 may detect the abnormality of the semiconductor switch 20 from the control signal transmitted from the control circuit 70 to the semiconductor switch 20 and the detected current of the semiconductor switch 20 . For example, when the control circuit 70 outputs a switch-off control signal to the semiconductor switch 20 and the detected current of the semiconductor switch 20 is higher than zero, the semiconductor switch 20 is turned on due to an abnormality in the semiconductor switch 20. There is a possibility of a close failure that does not return off from. The abnormality detector 30 can detect an abnormality of the semiconductor switch 20 by comparing the control signal and the detected current.

If the temperature of the power supply control device 100 or the ambient temperature of the power supply control device 100 is equal to or higher than a predetermined temperature threshold, the abnormality detector 30 detects an abnormal state due to high temperature based on the detection value of the temperature sensor (not shown). I judge. If the semiconductor switch 20 has a temperature detection function, the abnormality detector 30 may detect a high temperature abnormality of the semiconductor switch 20 based on the detected temperature of the semiconductor switch 20 .

The heating element 40 is a heater that generates heat when the abnormality detector 30 detects an abnormality. The operating power of the heating element 40 is taken from the battery 1 and the heating element 40 is connected to the power supply line 3 . The heating element 40 is installed at a position such that the heat generated by the heating element 40 is transferred to the power fuse 10 . The heating element 40 is composed of a seat heater, a spiral heating wire, a metal plate, or the like.

The protection circuit 50 is a circuit for protecting the heating element control switch 60 and is connected between the heating element 40 and the heating element control switch 60 . Since the heating element 40 is connected to the power supply line 3 , when a surge occurs, a surge current may flow through the heating element 40 to the heating element control switch 60 . The protection circuit 50 cuts off the surge current when a surge occurs to protect the heating element control switch 60 .

The heating element control switch 60 is a semiconductor component composed of a transistor such as an FET, and is connected to a current path through which the current from the power supply line 3 flows from the heating element 40 to the ground. The heating element control switch 60 is switched on and off under the control of the abnormality detector 30 . When the abnormality detector 30 detects an abnormal condition, the abnormality detector 30 outputs a control signal to the heating element 40 to turn on the switch. When the heating element control switch 60 is on, the current of the battery 1 flows through the heating element 40, and the heating element 40 operates. On the other hand, when the abnormality detector does not detect an abnormal state, the abnormality detector 30 keeps the heating element control switch 60 in an off state. When the heating element control switch 60 is off, the heating element 40 does not operate. Since the heating element control switch 60 is used to switch the heating element 40 on and off, it may be an FET that is smaller than the semiconductor switch 20 .

In addition, in this embodiment, a conventional vehicle fuse may be connected between the battery 1 and the power fuse 10 . Vehicle fuses are of a type that blows out an element when, for example, a large current exceeding the rating flows.

Next, the structures of the power fuse 10 and the heating element 40 will be described with reference to FIG. FIG. 2 is a cross-sectional view of the power control device 100. As shown in FIG. The power fuse 10 has an elastic body 11 and a fusing portion 12 . The elastic body 11 is composed of a metal spring material. The fusing portion 12 is a conductive portion that conducts current, and is fused by receiving heat from the outside. The fusing portion 12 is a portion of solder when the elastic body 11 is joined to the substrate pattern 81 by soldering.

Heating element 40 is mounted on substrate 80 . A substrate 80 includes a substrate pattern 81 and a pair of base materials 82 and 83 . The substrate pattern 81 is a wiring pattern and forms part of the conduction path including the power supply line 3 . A portion of the substrate pattern 81 where the power fuse 10 is mounted forms a path through which the current of the battery 1 flows to the load circuit 2 . The base materials 82 and 83 are insulating plate-like members. A power fuse 10 is mounted on the front surface of the base material 82 , and a heating element 40 is provided on the back surface of the base material 82 . In the example of FIG. 2, the heating element 40 is a heat sheeter and is provided along the back surface of the substrate 82 . Heating element 40 is sandwiched between substrates 82 and 83 .

Next, a structural mechanism for switching the power supply fuse 10 from conduction to cutoff when the abnormality detector 30 detects an abnormal state will be described. The abnormality detector 30 detects the current flowing through the semiconductor switch 20, and when the detected current exceeds the rated current (current threshold), it determines that there is an abnormal state due to overcurrent, and the heating element control switch 60 is turned off. turn on. When the heating element control switch 60 is turned on, the heating element 40 generates heat. Heat is transferred to the fusing portion 12 via the base material 82 and the substrate pattern 81 . When the fusing portion 12 receives heat, the solder melts and the bonding strength of the fusing portion 12 decreases. As the heating of the fusing portion 12 progresses, the elastic force of the elastic body 11 causes the elastic body 11 to open, and one of both ends of the elastic body 11 separates from the substrate pattern 81 . As a result, a part of the conduction path including the power supply line 3 is cut off, so that the current flowing from the battery 1 to the load circuit 2 is cut off.

As described above, the power control device 100 according to the present embodiment includes the semiconductor switch 20 connected to the power line 3, the power fuse 10 connected to the power line 3 on the upstream side of the semiconductor switch 20, and the abnormal state. and an anomaly detector 30 for detecting. When the abnormality detector 30 detects an abnormal state, the power fuse 10 cuts off the current, and when the abnormality detector 30 does not detect an abnormal state, the semiconductor switch 20 turns the current on and off. switch. As a result, it is possible to enhance the protection function when an abnormality occurs. In other words, the current flowing from the battery 1 to the load circuit 2 can be cut off when the semiconductor switch 20 cannot be switched on and off due to some abnormality.

Incidentally, unlike the present embodiment, a power control device 200 as shown in FIG. 3 has conventionally been used as a power control device for protecting the load circuit 2 when an abnormality such as an overcurrent occurs. Power supply control device 200 connects vehicle fuse 90 and semiconductor switch 20 to power supply line 3 . When the abnormality detector 30 detects an abnormal state, the semiconductor switch 20 is turned off. When the semiconductor switch 20 cannot switch on and off due to an abnormality, the power supply control device 200 protects the load circuit 2 from overcurrent by blowing the vehicle fuse 90 . However, for example, when a temperature abnormality occurs due to a high temperature while the current is equal to or less than the rated current, there is a problem that the configuration of the power supply control device 200 cannot cope with such a temperature abnormality.

Further, unlike the present embodiment, the power supply control device 300 shown in FIG. 4 has two semiconductor switches 20 connected in series to the power supply line 3, and when one semiconductor switch 20 malfunctions, the other semiconductor switch 20 controls the overheating. Some protect the load circuit 2 from current. However, in the power supply control device 300, the cost increases as the number of semiconductor switches 20 is increased. Moreover, when an overcurrent flows into the power supply line 3, the two semiconductor switches 20 may be in an abnormal state.

On the other hand, in the present embodiment, since the power fuse 10 is a mechanical element, the occurrence probability of an accidental abnormality that tends to occur in the semiconductor switch 20 is low.

Furthermore, the power supply control device 200 shown in FIG. 3 is not necessarily suitable for use in a vehicle if the semiconductor switch 20 is malfunctioning and the protective function is provided only by blowing the vehicle fuse 90 . When the battery 1 of the vehicle is used as a power supply for auxiliary equipment, a high current flows through the power supply line because it is necessary to drive a high-power load such as an air conditioner with the 12V battery. Assuming such a high current flow, a fuse with a higher current rating is used for the vehicle fuse 90 . On the other hand, when a high current close to the rated current flows through the semiconductor switch 20 for a long time, the possibility of malfunction of the semiconductor switch 20 increases due to other factors. On the other hand, in the present embodiment, even if a current that is less than the rated current of the vehicle fuse 90 and causes an abnormality in the semiconductor switch 20 flows, the current can be interrupted by the power fuse 10 . Thereby, a protection function can be improved.

Further, in this embodiment, when the abnormality detector 30 detects an abnormal state, the power supply fuse 10 cuts off the current in the power supply line 3. Therefore, the load circuit 2 can be protected with a simple structure while suppressing costs. . Furthermore, in the present embodiment, when a large current that cannot be controlled by the semiconductor switch 20 is applied, even if an overvoltage is applied, the abnormality detector 30 detects an abnormality associated with the large current or overvoltage, and the power supply fuse 10 detects the current. is cut off, the load circuit 2 can be protected.

Further, in this embodiment, the power fuse 10 is a conductive portion that conducts current, and has a fusing portion 12 that melts when receiving heat from the outside. Then, heat is applied to the fusing portion 12 . Thereby, when installing the power fuse 10, the degree of freedom of layout can be increased. For example, if the heating element 40 is not provided, the power fuse 10 must be provided in a portion of the substrate 80 that is likely to be heated in the event of an abnormality. On the other hand, by providing the heating element 40 as in the present embodiment, the heating element 40 serves as a heat source when an abnormality occurs. In place of the power fuse 10, a mechanical switch such as a relay may be connected to cut off the current, but the mechanical switch such as a relay has a complicated structure, which increases the cost. On the other hand, in the present embodiment, since the current can be cut off by fusing the fusing portion 12, the protection function can be enhanced while suppressing the cost.

Further, in this embodiment, the abnormality detector 30 turns on the heating element 40 when detecting an abnormal state. As a result, the heating element 40 becomes a heat source and the power fuse 10 can be fused.

Further, in this embodiment, the power control device 100 includes a base material 82 on which the power fuse 10 is mounted, and the heating element 40 is a pattern heater provided along the back surface of the base material 82 . Due to the characteristics of the substrate 80, the heat efficiency can be improved by placing the pattern heater directly under the base material 82. FIG.

Further, in the present embodiment, the abnormality detector 30 detects the current flowing through the power supply line 3, and when the detected current is equal to or greater than the current threshold, determines that an abnormality has occurred, and determines that an abnormality has occurred. If so, the heating element 40 is turned on. Thus, when an overcurrent flows through the power supply line 3, the heating element 40 becomes a heat source, and the power supply fuse 10 can be fused.

In this embodiment, the power supply control device 100 also has a heating element control switch 60 for switching the heating element 40 on and off. As a result, since the heating element can be driven by a small FET, the cost can be suppressed.

In the power control device 100, the power fuse 10 may be configured as a unit component integrated with an electronic control unit (ECU). The ECU is a control unit that controls loads included in the load circuit 2 . If the ECU is standardized so that it can be applied to various vehicles, by using the power fuse 10 as a unit component of the ECU, the ECU including the power control device 100 can be mounted on various vehicles.

Further, in the power control device 100, the power fuse 10 may be configured as a component separate from the ECU. Thereby, the power fuse 10 can be mounted on a board different from the board included in the ECU.

In this embodiment, since the heating element 40 has resistance, the protection circuit 50 may be miniaturized, or the protection circuit 50 may be fixed. Also, if an insulated power supply is used, it can be configured insulated from the power supply line 3, and robustness can be improved.

Reference Signs List 1 battery 2 load circuit 3 power line 10 power fuse 20 semiconductor switch 30 abnormality detector 40 heating element 50 protection circuit 60 heating element control switch 100 power control device

Claims (8)

In a power supply control device connected to a power supply line that supplies current from a power supply to a load circuit,
a semiconductor switch connected to the power supply line;
a power fuse connected to the power line upstream of the semiconductor switch;
and an anomaly detector for detecting an anomalous state,
when the abnormality detector detects the abnormal condition, the power fuse cuts off the current;
A power supply control device in which the semiconductor switch switches the current on and off when the abnormality detector does not detect the abnormal state. The power control device according to claim 1,
having a heating element,
The power fuse is a conductive portion that conducts the current, and has a fusing portion that melts when receiving heat from the outside,
The power control device, wherein the heating element applies the heat to the fusing portion when the abnormality detector detects the abnormal state. In the power control device according to claim 2,
The power control device, wherein the abnormality detector turns on the heating element when the abnormality detector detects the abnormality. In the power control device according to claim 2 or 3,
A base material for mounting the power fuse on the surface,
The power control device, wherein the heating element is a pattern heater provided along the back surface of the base material. In the power control device according to any one of claims 2 to 4,
The anomaly detector is
detecting the current flowing through the power supply line;
when the detected current is equal to or greater than the current threshold, determining that the abnormal state is present;
A power control device that turns on the heating element when it is determined that the abnormal condition exists. In the power supply control device according to any one of claims 1 to 5,
The power control device, wherein the abnormality detector detects at least one of overcurrent, overvoltage, high temperature, outgassing, and abnormality of the semiconductor switch. In the power supply control device according to any one of claims 1 to 6,
The power control device, wherein the power fuse is configured as a unit component integrated with the electronic control device. In the power supply control device according to any one of claims 1 to 6,
The power control device, wherein the power fuse is a component separate from the electronic control device.

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