Vehicle control device

Abstract

To provide a vehicle control device capable of continuing to operate a loading device even if a radiation failure occurs in a semiconductor device for controlling operation of the loading device.SOLUTION: A controller 30 includes a semiconductor switch 5 for controlling operation of a control object powered by a battery 4, a temperature detection element 8 for detecting an internal temperature of the semiconductor switch 5 as an actual temperature, a temperature estimation unit 11 for estimating the internal temperature as an estimated temperature based on current supplied to the semiconductor switch 5, a determination unit 12 for outputting a determination result that determines a radiation failure of the semiconductor switch 5 based on temperature difference between the actual temperature and the estimated temperature, and a driving management unit 13 which manages operation of the semiconductor switch 5 so that the actual temperature is lower than an overtemperature threshold value when the determination result is obtained that the semiconductor switch 5 has the radiation failure and continues to operate the semiconductor switch 5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Conventionally, semiconductor switches using power semiconductors have been used to prevent overheating, smoke, and fires caused by overcurrent in electric or electronic devices. Some semiconductor switches have a built-in current sensor and temperature sensor to prevent or detect overheating of the semiconductor switch itself for protection. Examples of such semiconductor switches include IPMs (Intelligent Power Modules) and IPDs (Intelligent Power Devices).

[0003] Patent document 1 states that "one or more units have a second temperature sensor outside the IPM for detecting the temperature of the IPM, in addition to a first temperature sensor built into the IPM, and when the temperature detection result by the second temperature sensor exceeds a predetermined first threshold value that is lower than the temperature at which the IPM's overheat protection function is activated by the first temperature sensor, the control unit reduces the maximum drive current to the work motor if the unit is an inverter unit." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-226782 A Summary of the Invention [Problem to be solved by the invention]

[0005] With the technology disclosed in Patent Document 1, for example, a temperature sensor outside the IPM detects the temperature outside the IPM before the self-protection function of the IPM is activated, enabling protection operation of a system that uses a unit including a semiconductor switch, etc. However, if the protection operation of the system is suddenly activated, the vehicle's functions may suddenly stop, compromising the safety and convenience of the vehicle.

[0006] As vehicle functions continue to improve in the future, it is expected that the number of calculations in automotive ECUs (Electronic Control Units) will increase due to the integration of control functions, and that the amount of heat generated by vehicle control devices will increase due to the consolidation of power supply functions to actuators. If the thermal shock cycles that vehicle control devices are subjected to become more severe, deterioration of the packages of semiconductor elements and deterioration of the board mounting materials will occur more easily. If the heat dissipation ability of semiconductor elements deteriorates due to deterioration of such materials, there is a risk that sudden function shutdowns due to overheating will occur frequently.

[0007] The present invention has been made in view of the above circumstances, and has an object to continue the operation of a controlled object even if a heat dissipation problem occurs in an operation control unit that controls the operation of the controlled object. [Means for solving the problem]

[0008] The vehicle control device according to the present invention includes an operation control unit that controls an operation of a control target to which power is supplied from a power supply unit; a current detection unit that detects a current supplied from the power supply unit to the operation control unit; An actual temperature detection unit that detects the internal temperature of the operation control unit as an actual temperature, and a current supplied to the operation control unit a current detection signal output from the current detection unit, and thermal resistances and thermal capacities of components of the operation control unit; a temperature estimating unit that estimates an internal temperature as an estimated temperature based on the temperature difference between the actual temperature and the estimated temperature; A first threshold and a second threshold are provided for comparing the above, and when the actual temperature is less than the over-temperature threshold and the temperature difference is less than the first threshold, Motion control section If the temperature difference is equal to or greater than a first threshold value, the state of the operation control unit is determined to be a poor heat dissipation state, and if the temperature difference is equal to or greater than a second threshold value, the state of the operation control unit is determined to be a state in which the poor heat dissipation state has progressed. Judgment result and a determination result of determining which component has an abnormality based on a change in temperature difference between each component of the operation control unit after the start of energization of the operation control unit. A determination unit that outputs Status Poor heat dissipation It was determined that the condition When a judgment result is obtained, The power supplied to the controlled object by the operation control unit is limited to less than the power supplied in a normal state, and when it is determined that the heat dissipation failure state has progressed, the operation control unit stops the power supplied to the controlled object. The operation of the operation control unit is managed so that the actual temperature is below the over-temperature threshold, and the operation of the operation control unit is continued. Before the operation control unit stops supplying power to the controlled object, the operation control unit notifies the state of the operation control unit and the result of the determination of the component in which an abnormality has occurred. and a management unit. Effect of the Invention

[0009] According to the present invention, even if a heat dissipation problem occurs in an operation control unit that controls the operation of a controlled object, the controlled object can continue to operate. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a power supply system according to a first embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view showing an example of a package structure of a semiconductor switch according to a first embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram showing an example of an equivalent thermal circuit network when a semiconductor substrate is used as a heat source in the package structure of the semiconductor switch according to the first embodiment of the present invention. [Figure 4] 4 is a diagram showing transitions in the package state of the semiconductor switch according to the first embodiment of the present invention, and the relationship between the chip temperature and the actuator power for each package state. FIG. [Diagram 5] 5A and 5B are diagrams showing an example of actual temperature information and estimated temperature information when a defect occurs in the die attachment or soldering of the semiconductor switch according to the first embodiment of the present invention. [Figure 6] 13 is a diagram showing another example of actual temperature information and estimated temperature information when poor adhesion occurs between the die attach and the printed circuit board in the semiconductor switch according to the first embodiment of the present invention. FIG. [Figure 7] FIG. 1 is a schematic configuration diagram of a controller having a semiconductor switch with a current detection function according to a first embodiment of the present invention. [Figure 8] FIG. 1 is a schematic configuration diagram of a controller having a semiconductor switch with an actual temperature information detection function according to a first embodiment of the present invention. [Figure 9] FIG. 11 is a schematic configuration diagram of a controller having a semiconductor switch that does not have a function of outputting actual temperature information according to a second embodiment of the present invention. [Figure 10]13 is a diagram showing transitions of the package state of the semiconductor switch according to the second embodiment of the present invention, and relationships between the operation monitoring state, estimated temperature information, and actuator power for each package state. FIG. [Figure 11] FIG. 11 is a diagram illustrating an example of the configuration of a controller in which a plurality of load devices are connected to a semiconductor switch according to a third embodiment of the present invention. [Figure 12] FIG. 13 is a diagram showing a configuration example of a controller in which a plurality of semiconductor switches are branch-connected downstream of a semiconductor switch according to a fourth embodiment of the present invention. [Figure 13] FIG. 13 is a diagram illustrating a configuration example of a controller including a plurality of semiconductor switches according to a fifth embodiment of the present invention. [Figure 14] FIG. 13 is a schematic configuration diagram of a power supply system according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functions or configurations are designated by the same reference numerals, and redundant description will be omitted.

[0012] [First embodiment] 1 is a schematic configuration diagram of a power supply system 1 according to a first embodiment. The power supply system 1 mounted on a vehicle is configured as, for example, a part of an automobile engine ECU or an on-board integrated ECU.

[0013] The power supply system 1 includes a load device 2, a battery 4, and a controller 30. The battery 4 is, for example, a chargeable and dischargeable secondary battery. The battery 4 supplies power to the load device 2. The load device 2 is a device that is driven by electric power. Examples of the load device 2 include actuators such as vehicle lamps, compressors, PTC heaters, cooling pump motors, and fan motors. In the following description, the load device 2 may be referred to as an actuator.

[0014] The controller 30 is an example of a vehicle control device that is mounted on a vehicle and controls the operation of the vehicle. The controller 30 includes a control unit 3, a semiconductor switch 5, a shunt resistor 10, and a temperature sensor 14. The control unit 3 controls the power supplied to the load device 2 and outputs an operation command for the load device 2. The control unit 3 is configured, for example, by a microcomputer in which a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. are integrated. The CPU reads out program code of software that realizes each function according to this embodiment from the ROM, loads it into the RAM, and executes it. Variables, parameters, etc. generated during the CPU's arithmetic processing are temporarily written to the RAM, and these variables, parameters, etc. are read out by the CPU as appropriate.

[0015] The battery 4 supplies power to the load device 2 through a power line 9b. One end of the power line 9b is connected to the battery 4, and the other end is connected to a shunt resistor 10. The current detection unit (shunt resistor 10) is provided to detect a current supplied from the power supply unit (battery 4) to the operation control unit (semiconductor switch 5). An IPD is used as the semiconductor switch 5, for example. The current detection unit according to this embodiment is a shunt resistor (shunt resistor 10) connected in series to the semiconductor switch (semiconductor switch 5). By measuring the current flowing through the shunt resistor 10, it is possible to detect the current of the power line 9a controlled by the semiconductor switch 5. By using the shunt resistor 10 as the current detection unit, it is possible to simplify the configuration of the current detection.

[0016] A power supply input terminal of the semiconductor switch 5 is connected to the battery 4 via a shunt resistor 10. That is, the shunt resistor (shunt resistor 10) is provided between the power supply unit (battery 4) and the semiconductor switch (semiconductor switch 5). Therefore, the current supplied from the battery 4 to the semiconductor switch 5 can be detected via the shunt resistor 10. One end of a power line 9a is connected to an output terminal of the semiconductor switch 5. The other end of the power line 9a is connected to a power supply input terminal of the load device 2. The power line 9a branches and is connected to a temperature estimator 11. The power supply input terminal of the semiconductor switch 5 is connected to the temperature estimator 11 via an input terminal of the controller 3. That is, the voltage across the semiconductor switch 5 is input to the temperature estimator 11.

[0017] The operation control unit (semiconductor switch 5) controls the operation of the control target (load device 2) to which power is supplied from the power supply unit (battery 4). The operation control unit according to this embodiment is a semiconductor switch (semiconductor switch 5) that controls the power supplied to the control target (load device 2). By using the semiconductor switch 5 as the operation control unit, the function of the operation control unit can be realized by the semiconductor switch 5. This semiconductor switch 5 controls the ON / OFF of the power supplied from the battery 4 mounted on the vehicle based on an ON / OFF command input from the drive management unit 13, and controls the power supply to the load device 2. Thus, the semiconductor switch 5 according to this embodiment includes, as an example, a power semiconductor 6, a gate drive circuit 7 that outputs an ON or OFF voltage (or current) to the gate terminal of the power semiconductor 6, and a temperature detection element 8 that detects the internal temperature of the power semiconductor 6.

[0018] The temperature sensor 14 detects the ambient temperature of the semiconductor switch 5. The ambient temperature of the semiconductor switch 5 detected by the temperature sensor 14 becomes a reference for the estimated temperature estimated by the temperature estimation unit 11. A thermistor installed near the semiconductor switch 5 can be used as the temperature sensor 14. Note that, other than the thermistor, an element capable of detecting a reference temperature for the estimated temperature may also be used as the temperature sensor 14.

[0019] The control unit 3 includes a temperature estimation unit 11, a determination unit 12, and a drive management unit 13. The temperature estimation unit (temperature estimation unit 11) estimates the internal temperature as an estimated temperature based on the current supplied to the operation control unit (semiconductor switch 5). This temperature estimation unit (temperature estimation unit 11) detects the current supplied to the semiconductor switch (semiconductor switch 5) based on the voltage across the shunt resistor (shunt resistor 10). By using the shunt resistor 10 as a current detection unit for detecting the current in this manner, the configuration of the current detection can be simplified. Then, the temperature estimation unit (temperature estimation unit 11) estimates the estimated temperature based on the current detection signal output from the current detection unit (shunt resistor 10) and the thermal resistance and heat capacity of the components of the operation control unit (semiconductor switch 5). For this reason, the temperature estimation unit 11 detects the power consumption of the semiconductor switch 5 based on the current detected by the shunt resistor 10 and the voltage across the semiconductor switch 5. Then, the temperature estimation unit 11 outputs estimated temperature information 15, which is obtained by calculating the internal temperature of the semiconductor switch 5 based on the detected power consumption, to the determination unit 12.

[0020] Here, the temperature estimation unit 11 can estimate a temperature change (e.g., +30° C.) relative to the temperature after the controller 30 is started up, based on the power consumption of the power semiconductor 6. Then, the temperature estimation unit 11 can estimate the internal temperature (e.g., 55° C.) of the semiconductor switch 5 by adding the estimated temperature change to the ambient temperature (e.g., 25° C.) detected by the temperature sensor 14.

[0021] As described above, the ambient temperature of the semiconductor switch 5 detected by the temperature sensor 14 is used in the calculation of the estimated temperature information 15. The ambient temperature of the semiconductor switch 5 is used as a reference temperature for temperature estimation by the determination unit 12. A method for the temperature estimation unit 11 to estimate the internal temperature of the semiconductor switch 5 will be described later.

[0022] The determination unit (determination unit 12) outputs a determination result of heat dissipation failure of the operation control unit (semiconductor switch 5) based on the temperature difference between the actual temperature and the estimated temperature. For example, the determination unit 12 outputs a determination result of whether the semiconductor switch 5 is normal or abnormal based on the estimated temperature acquired from the estimated temperature information 15 and the actual temperature inside the semiconductor switch 5 acquired from the actual temperature information 16 output from the temperature detection element 8 included in the semiconductor switch 5.

[0023] The actual temperature detection unit (temperature detection element 8) detects the internal temperature of the operation control unit (semiconductor switch 5) as the actual temperature. The actual temperature detection unit (temperature detection element 8) is any one of a diode element, a resistor element, or a thermistor element provided on a semiconductor substrate constituting the semiconductor switch (semiconductor switch 5). For example, the temperature detection element 8 can utilize the temperature dependency of the voltage drop when a forward current flows through a diode element provided on the same substrate as the power semiconductor 6 inside the semiconductor switch 5. In addition, for example, a temperature-dependent resistor element or thermistor element may be used as the temperature detection element 8. By using such an element, the cost of constructing the temperature detection element 8 can be reduced. The method by which the determination unit 12 determines whether the semiconductor switch 5 is normal or abnormal will be described in detail later.

[0024] The drive management unit 13 issues an ON / OFF command for the semiconductor switch 5 based on the input drive command 17. The drive command 17 is, for example, a signal output from a light switch to the drive management unit 13 when a driver of the vehicle presses a light switch for turning the front lights ON or OFF. The ON / OFF command output by the drive management unit 13 is input to the gate drive circuit 7 of the semiconductor switch 5 and controls the drive of the load device 2 via the power semiconductor 6.

[0025] When the management unit (drive management unit 13) obtains a result indicating that the operation control unit (semiconductor switch 5) has poor heat dissipation, the management unit manages the operation of the operation control unit (semiconductor switch 5) so that the actual temperature is less than the overtemperature threshold, and continues the operation of the operation control unit (semiconductor switch 5). At this time, when the drive management unit 13 receives an abnormality determination from the determination unit 12, the drive management unit 13 corrects the drive command 17 and outputs an OFF command to limit the drive of the load device 2 through the power semiconductor 6. When the drive management unit 13 limits the drive of the semiconductor switch 5, the power consumption of the semiconductor switch 5 is suppressed, so that the semiconductor switch 5 can be prevented from breaking down or stopping due to overtemperature. Even if the semiconductor switch 5 is thus determined to have poor heat dissipation, the semiconductor switch 5 is not immediately shut off, but the operation of the semiconductor switch 5 is continued so that the actual temperature is less than the overtemperature threshold. Therefore, even if the semiconductor switch 5 deteriorates, the operation restriction of the semiconductor switch 5 can be minimized to maintain important functions as a vehicle.

[0026] As a method for the drive management unit 13 to limit the drive of the load device 2, for example, when the load device 2 is driven by pulse width modulation (PWM), there is a method of lowering the carrier frequency in the PWM waveform.

[0027] <Method of estimating the internal temperature of a semiconductor switch> Next, a method in which the temperature estimator 11 in this embodiment estimates the internal temperature of the semiconductor switch 5 will be described with reference to Fig. 2 and Fig. 3. In this embodiment, an example of a method for estimating the heat dissipation characteristics according to the package structure and mounting structure of the semiconductor switch 5 by modeling them using an equivalent thermal circuit network will be shown.

[0028] FIG. 2 is a cross-sectional view showing an example of a package structure of the semiconductor switch 5. As shown in FIG.

[0029] The semiconductor switch 5 includes a semiconductor substrate 18 on which a power semiconductor 6 is formed using a semiconductor process. The semiconductor substrate 18 is attached to a die pad 20 by a die attach 19. As a material for the die attach 19, for example, solder or the like is used. As a material for the die attach 19, an adhesive film made of resin or the like can also be used in addition to solder.

[0030] Also, for example, a frame mainly made of copper can be used as the die pad 20. The power semiconductor 6 formed on the semiconductor substrate 18 is connected to the terminal 21 by a bonding wire. These components are resin molded by injection molding.

[0031] The terminals 21 are electrically connected by solder or the like to a circuit formed on a printed circuit board 22. A microcomputer (not shown) and the like are also mounted on the printed circuit board 22. The die pad 20 is attached to the conductor pattern of the printed circuit board 22 by solder 23 or the like. Heat generated in the semiconductor substrate 18 is dissipated to the printed circuit board 22 via the die pad 20 along the heat dissipation path indicated by the white arrow in the figure.

[0032] FIG. 3 is a diagram showing an example of an equivalent thermal circuit network when the semiconductor substrate 18 is used as a heat source in the package structure of the semiconductor switch 5 shown in FIG.

[0033] 3, “P” represents the amount of heat generated by the semiconductor substrate 18. The amount of heat generated by the semiconductor substrate 18 is determined from the power consumption calculated based on the current detected by the shunt resistor 10 and the voltage across the semiconductor switch 5.

[0034] In addition, in the figure, "R1" and "C1" represent the thermal resistance and heat capacity of the semiconductor substrate 18, "R2" and "C2" represent the thermal resistance and heat capacity of the die attach 19, "R3" and "C3" represent the thermal resistance and heat capacity of the die pad 20, and "R4" and "C4" represent the thermal resistance and heat capacity of the solder 23 and the printed circuit board 22.

[0035] The ground symbol in the figure represents the ambient temperature of the semiconductor switch 5, and the information detected by the temperature sensor 14 can be used as the ambient temperature. The thermal resistance and heat capacity shown in the figure can be extracted by measuring the thermal impedance of the semiconductor switch 5.

[0036] The temperature to be estimated by the temperature estimation unit 11 is the temperature Tj of the semiconductor substrate 18 shown in Fig. 2. Therefore, the temperature estimation unit 11 can estimate the temperature Tj from the power consumption by calculating the temperature Tj based on the equivalent thermal network shown in Fig. 3. In the present embodiment, a method of calculating Tj by calculation has been described, but a method of creating map data showing the relationship between the power consumption and the temperature using the calculation result in the equivalent thermal network and searching for a temperature according to the power consumption may also be used.

[0037] The advantage of the method for estimating temperature Tj according to this embodiment is that it can estimate the internal temperature of the semiconductor switch 5 with high response and can estimate the temperature while following a sudden increase in the internal temperature. In addition, since the temperature estimator 11 estimates the temperature at the same position as the actual temperature information obtained from the temperature detection element 8 formed on the semiconductor substrate 18, it becomes easy to compare the estimated temperature with the actual temperature information.

[0038] Next, a method for determining whether the semiconductor switch 5 is normal or abnormal in the determination unit 12 and an embodiment of power management for the actuator will be described with reference to Fig. 4. In the following description, the actuator is an example of the load device 2 shown in Fig. 1.

[0039] <Power control according to package state> Fig. 4 is a diagram showing the transition of the package state of the semiconductor switch 5 and the relationship between the chip temperature and the actuator power for each package state. In Fig. 4, the package state of the semiconductor switch 5 transitions in the order of a normal state, a poor heat dissipation state in which the package has deteriorated or the adhesive state with the printed circuit board 22 has deteriorated, causing poor heat dissipation, and a state in which the poor heat dissipation has progressed. The control state according to this embodiment for each package state is also shown.

[0040] The deteriorated state of the package refers to a state in which good thermal conduction in the semiconductor switch 5 is lost due to repeated thermal shocks being applied to the semiconductor switch 5. For example, if a crack occurs in the solder used for the die attach 19 or in the solder 23 that is the adhesive between the die pad 20 and the printed circuit board 22 in the cross-sectional structure of the semiconductor switch 5 shown in FIG. 2, the package state deteriorates and becomes abnormal.

[0041] (Normal state) In FIG. 4, when the package state is normal, the drive management unit 13 drives the semiconductor switch 5 in the normal mode. Then, the chip temperature Tj indicated by the actual temperature information obtained from the temperature detection element 8 formed on the semiconductor substrate 18 inside the semiconductor switch 5 and the chip temperature Tj indicated by the estimated temperature information obtained by the temperature estimation unit 11 are in a state of agreement. In the following description, the chip temperature Tj indicated by the actual temperature information is abbreviated as "actual temperature information", and the chip temperature Tj indicated by the estimated temperature information is abbreviated as "estimated temperature information". Even if the actual temperature information and the estimated temperature information when the package state is normal do not completely match, it can be determined to be normal as long as the difference in information is within a certain range. When the package state of the semiconductor switch 5 is normal, the power supplied to the actuator is controlled to be equal to or lower than a specified limit value so that the IPD estimated temperature is less than an overtemperature threshold (for example, 150°C).

[0042] (Poor heat radiation) When poor heat dissipation occurs in the package, heat tends to accumulate in the semiconductor switch 5, causing the actual temperature information to rise. On the other hand, the estimated temperature information is estimated based on the heat dissipation structure when the semiconductor package is in a normal state. Therefore, if the power consumption of the semiconductor switch 5 remains the same, the estimated temperature information will not change even if the package deteriorates.

[0043] However, as shown in Fig. 4, a temperature difference ΔT occurs between the actual temperature information and the estimated temperature information. Therefore, the judgment unit (judgment unit 12) compares the temperature difference added to the estimated temperature with an over-temperature threshold value, and judges the state of the operation control unit (semiconductor switch 5) as either a normal state or a poor heat dissipation state (also called "abnormal"). By the judgment unit 12 judging the state of the semiconductor switch 5 as either a normal state or a poor heat dissipation state, it becomes easier for the drive management unit 13 to manage the drive of the semiconductor switch 5. Then, when the temperature difference ΔT increases to the first threshold value ΔT1, the judgment unit 12 judges that the package state is one in which poor heat dissipation has occurred.

[0044] When the state of the operation control unit (semiconductor switch 5) is determined to be in a poor heat dissipation state, the management unit (drive management unit 13) limits the power supplied by the operation control unit (semiconductor switch 5) to the controlled object (load device 2) to a level lower than the power supplied in a normal state. For example, upon receiving the determination result of the poor heat dissipation state from the determination unit 12, the drive management unit 13 switches to a power limit mode that limits the operation of the actuator. The drive management unit 13 switches to the power limit mode and outputs an ON / OFF command to the gate drive circuit 7, thereby limiting the power supplied to the load device 2 via the semiconductor switch 5. The limit value of the power supplied to the actuator when the package state is in a poor heat dissipation state is updated to a value lower than the limit value when the package state is normal. Therefore, even if the heat dissipation state is poor, the actual temperature information returns to a value that is expected when the package state is normal.

[0045] (Progression of poor heat dissipation) Even if the operation of the semiconductor switch 5 is controlled in the power limiting mode, the heat dissipation performance of the semiconductor switch 5 deteriorates, and the heat dissipation failure progresses, causing the package state to further deteriorate. Then, the actual temperature information starts to rise again. When the temperature difference ΔT between the actual temperature information and the estimated temperature information increases to a second threshold ΔT2 that is larger than the first threshold ΔT1, the determination unit 12 determines that the package state is one in which heat dissipation failure has progressed.

[0046] When the judgment unit 12 judges that the heat dissipation failure has progressed further, the management unit (drive management unit 13) stops the power supplied by the operation control unit (semiconductor switch 5) to the controlled object (load device 2). For example, upon receiving a judgment result from the judgment unit 12 that the heat dissipation failure has progressed, the drive management unit 13 stops the operation of the actuator. For this reason, the drive management unit 13 outputs an OFF command to the gate drive circuit 7, and the semiconductor switch 5 cuts off the supply of power. Then, the actuator whose electrode supply has been cut off stops. In this way, as the heat dissipation failure progresses, the drive management unit 13 gradually limits the power supplied by the semiconductor switch 5 to the load device 2, thereby making it possible to prevent the load device 2 from being unintentionally stopped due to a sudden stop of the semiconductor switch 5.

[0047] With the above-described configuration of the controller 30, the determination unit 12 can quantitatively determine the deterioration state of the package of the semiconductor switch 5 based on the temperature difference calculated from the actual temperature information and the estimated temperature information. Then, the drive management unit 13 can output a command according to the deterioration state to the semiconductor switch 5. Therefore, the semiconductor switch 5 can avoid a sudden cutoff of the power supply due to a temperature rise of the semiconductor switch 5 by limiting the power supplied to the load device 2.

[0048] Furthermore, since the determination unit 12 can quantitatively detect the deterioration state of the package, the drive management unit 13 can quantify the amount of power to be limited based on the difference between the estimated temperature information and the actual temperature information, and limit the amount of power to the minimum necessary to continue operation of the load device 2. Quantification means, for example, that the drive management unit 13 determines the amount of power to be limited by the semiconductor switch 5 according to the temperature difference found from the estimated temperature information and the actual temperature information.

[0049] Furthermore, the drive management unit 13 limits the operation of the actuator based on the deterioration state of the package, thereby slowing down the progression of deterioration of the package and enabling the functionality of the semiconductor switch 5 to be maintained for a long period of time.

[0050] Furthermore, in the past, maintenance was performed after the semiconductor switch 5 failed, which required the load device 2 to be stopped. On the other hand, with the control according to the present embodiment, the drive management unit 13 limits the amount of power to the minimum necessary and continues the operation of the load device 2. Then, the drive management unit 13 can notify the user or maintenance company of the deterioration state and deteriorated parts of the package before the semiconductor switch 5 completely fails and operation stops. Therefore, maintenance of the controller 30 including the semiconductor switch 5 can be performed at the stage when poor heat dissipation is first reported, before the semiconductor switch 5 completely fails and the power supply is cut off.

[0051] <Temperature changes in semiconductor switches> Next, the state of temperature change of semiconductor switch 5 that occurs when a defect occurs in the package will be described with attention to the components of the package of semiconductor switch 5 shown in FIG.

[0052] Fig. 5 is a diagram showing an example of actual temperature information and estimated temperature information when a defect occurs in the die attach 19 or solder 23 of the semiconductor switch 5. The horizontal axis of Fig. 5 represents time [seconds], and the vertical axis represents temperature [°C]. In addition, the dashed line graph in the figure represents actual temperature information, and the solid line graph represents estimated temperature information.

[0053] 5A shows an example of temperature change when a crack occurs in the die attach 19. When a crack occurs in the die attach 19, the thermal resistance increases even immediately after current is applied. Therefore, a temperature difference occurs between the actual temperature information and the estimated temperature information at the beginning of current application. In other words, a temperature difference occurs in the die attach 19 even when it is heated for a short period of time.

[0054] 5B shows an example of temperature change when a crack occurs in solder 23, deteriorating the bonding state with printed circuit board 22. Because the distance from semiconductor substrate 18, which is the heat source, to solder 23 is longer than the distance from semiconductor substrate 18 to die attach 19, the heat is transferred to solder 23 after filling the heat capacity of each component of the package. For this reason, the actual temperature information and estimated temperature information match immediately after current is applied, but the difference between the actual temperature information and estimated temperature information gradually increases.

[0055] Fig. 6 is a diagram showing another example of actual temperature information and estimated temperature information when poor adhesion occurs between die attach 19 and printed circuit board 22 in semiconductor switch 5. The horizontal axis of Fig. 6 indicates time [seconds], and the vertical axis indicates chip temperature [°C]. Fig. 6 shows the transition of chip temperature when load device 2, which repeats ON / OFF operation, is connected to semiconductor switch 5.

[0056] 6A is an example of the temperature when a crack occurs in the die attach 19. When a crack occurs in the die attach 19, a temperature difference occurs between the actual temperature information and the estimated temperature information even with a single ON operation. On the other hand, the temperature difference between the actual temperature information and the estimated temperature information becomes smaller with an OFF operation. In other words, the determination unit 12 can detect poor heat dissipation caused by a defect in the die attach 19 by detecting the temperature difference during the ON operation period.

[0057] 6B shows an example of temperature transition when a crack occurs in the solder 23 and the bonding state with the printed circuit board 22 deteriorates. When a crack occurs in the solder 23, the difference between the actual temperature information and the estimated temperature information gradually increases after current is applied. Then, a temperature difference occurs in both the ON period and the OFF period. Therefore, after a certain time has elapsed after current is applied (e.g., 5 seconds), the judgment unit 12 detects the temperature difference in both the ON period and the OFF period, and thus it is possible to detect poor heat dissipation due to defects in the solder 23.

[0058] From the above, depending on the defective part of the semiconductor switch 5, there are times when a temperature difference occurs and times when it does not occur. Therefore, if the judgment unit 12 detects the temperature difference during the period when the semiconductor switch 5 is ON, it can detect poor heat dissipation for any defect. Furthermore, the judgment unit 12 can identify the faulty part based on whether or not a temperature difference occurs during both the ON period and the OFF period. Therefore, after starting to pass electricity through the semiconductor switch (semiconductor switch 5), the judgment unit (judgment unit 12) judges the component in which an abnormality has occurred based on the change in the temperature difference for each component of the semiconductor switch (semiconductor switch 5). Since the component in which an abnormality has occurred is judged in this way, it becomes easier to identify the cause of poor heat dissipation when the semiconductor switch 5 has poor heat dissipation.

[0059] The controller 30 according to the first embodiment quantitatively detects malfunctions in the heat dissipation path of the semiconductor switch 5 due to peeling inside the package of the semiconductor switch 5 or deterioration of board mounting materials such as heat dissipation grease and solder. Then, the drive management unit 13 limits the power supplied by the semiconductor switch 5 to the load device 2 before the semiconductor switch 5 completely breaks down, thereby avoiding sudden shutoff of the semiconductor switch 5 as much as possible according to the level of the abnormality and maintaining the function of the load device 2.

[0060] <Effect of configuring shunt resistor> Here, in the controller 30 according to this embodiment, a shunt resistor 10 is provided between the battery 4 and the semiconductor switch 5. This allows the temperature estimator 11 to constantly detect the total current flowing through the semiconductor switch 5, regardless of whether the semiconductor switch 5 is in an ON or OFF state. Furthermore, since the temperature estimator 11 can constantly detect the total current, the accuracy of temperature estimation of the semiconductor switch 5 can be improved.

[0061] In addition, even if a short circuit occurs in the internal circuit of the semiconductor switch 5, by configuring the semiconductor switch 5 so that a shunt resistor 10 is installed between the battery 4 and the semiconductor switch 5, the temperature estimation unit 11 can detect a current abnormality in the semiconductor switch 5.

[0062] <Other forms of current sensing function> In this embodiment, the shunt resistor 10 is used as a preferred configuration for detecting the current flowing through the semiconductor switch 5, but the present invention is not limited to this. Here, another embodiment of the controller 30 having a current detection function will be described with reference to FIG.

[0063] <Semiconductor switch with current detection function> FIG. 7 is a schematic diagram of a controller 30A having a semiconductor switch 5A with a current detection function.

[0064] The power supply system 1 shown in FIG. 7 has a configuration in which the controller 30 included in the power supply system 1 shown in FIG. 1 is replaced with a controller 30A. The controller 30A is configured by removing the shunt resistor 10 from the controller 30 shown in Fig. 1 and replacing the semiconductor switch 5 with a semiconductor switch 5A. This semiconductor switch 5A includes a current sense MOS FET 6A, a gate drive circuit 7, and a temperature detection element 8. In this manner, the semiconductor switch (semiconductor switch 5A) has a current sense MOSFET (current sense MOSFET 6A) that detects the current supplied to the semiconductor switch (semiconductor switch 5A) as a current detection unit. Since the semiconductor switch 5A itself detects the current, the controller 30A can be configured without the shunt resistor 10.

[0065] As described above, the current sense MOS FET 6A replaces the power semiconductor 6 of the semiconductor switch 5 shown in FIG. 1, and has a current detection function. This current sense MOS FET 6A detects a current by forming a mirror circuit with a MOS FET that passes a large current and a MOS FET that matches well with the MOS FET. The current of this mirror circuit flows through resistor 24, and a voltage is also applied to resistor 24. An amplifier circuit, an A / D conversion circuit, and the like (not shown) are provided on the path from resistor 24 to temperature estimation unit 11. Then, temperature estimation unit 11 can detect the current flowing through semiconductor switch 5A by detecting the voltage applied to resistor 24.

[0066] <Controller with actual temperature information detection function> In this embodiment, the temperature detection element 8 is provided inside the semiconductor switch 5 to detect actual temperature information, but the present invention is not limited to this. Actual temperature information can also be detected in other embodiments.

[0067] FIG. 8 is a schematic diagram of a controller 30B having a semiconductor switch 5B with an actual temperature information detection function.

[0068] The power supply system 1 shown in FIG. 8 has a configuration in which the controller 30 included in the power supply system 1 shown in FIG. 1 is replaced with a controller 30B. The controller 30B includes a control unit 3A and the semiconductor switch 5B shown in Fig. 8. The semiconductor switch (semiconductor switch 5B) has a current sense MOS FET (current sense MOSFET 6A) that detects a current supplied to the semiconductor switch (semiconductor switch 5B) as a current detection unit. Since the semiconductor switch 5B itself detects a current, the controller 30B can be configured without the shunt resistor 10.

[0069] The control unit 3A has a configuration in which an actual temperature calculation unit 25 is added to the control unit 3 shown in FIG. 7. Moreover, semiconductor switch 5B has a configuration in which temperature detection element 8 is removed from semiconductor switch 5A shown in FIG.

[0070] The actual temperature detection unit (actual temperature calculation unit 25) outputs actual temperature information of the actual temperature calculated based on the change in the on-resistance of the current sense MOSFET (current sense MOS FET 6A) to the judgment unit (judgment unit 12). Since the control unit 3A itself can detect the actual temperature, the controller 30B can be configured without the temperature detection element 8. For example, the actual temperature calculation unit 25 has a function of detecting actual temperature information using the temperature dependency of the on-resistance of the current sense MOS FET 6A provided in the semiconductor switch 5B. The on-resistance is the resistance between the source and drain of the current sense MOS FET 6A when current is applied, and can be calculated from the voltage and current between the source and drain according to Ohm's law. When the temperature of the current sense MOS FET 6A rises, the resistance value between the source and drain increases. The voltage across both ends of the semiconductor switch 5B (the voltages at points A and B) is input to the actual temperature calculation unit 25 as the source-drain voltage.

[0071] Moreover, actual temperature calculation unit 25 detects the source-drain current using current sense MOS FET 6A in semiconductor switch 5B, and further using the voltage of resistor 24 that detects the current of current sense MOS FET 6A. Then, actual temperature calculation unit 25 calculates the resistance value of the on-resistance of current sense MOS FET 6A based on the detected source-drain voltage and source-drain current, and calculates the temperature from the relationship between the temperature and the resistance value.

[0072] In the present embodiment, the current detection element and the temperature detection element are shown, but the controller and the semiconductor switch may be configured by appropriately combining these elements and detection methods. In addition, an amplifier may be appropriately used for current detection and voltage detection.

[0073] [Second embodiment] Next, a configuration example of a power supply system according to a second embodiment of the present invention will be described. In this embodiment, a configuration example of a controller 30C including a semiconductor switch 5C that does not have a function of outputting actual temperature information will be described.

[0074] 9 is a schematic diagram of a controller 30C having a semiconductor switch 5C that does not have a function of outputting actual temperature information. This semiconductor switch 5C has a protection circuit 26 that protects the semiconductor switch 5C itself, and the temperature detection element 8 outputs actual temperature information to the protection circuit 26.

[0075] The power supply system 1 shown in FIG. 9 has a configuration in which the controller 30 included in the power supply system 1 shown in FIG. 1 is replaced with a controller 30C. The controller 30C includes a control unit 3B and a semiconductor switch 5C.

[0076] The semiconductor switch 5C controls the ON / OFF of the power from the battery 4 and controls the power supply to the load device 2. The semiconductor switch 5C includes a power semiconductor 6, a gate drive circuit 7, a temperature detection element 8, and a protection circuit 26. That is, the semiconductor switch 5C is configured by adding the protection circuit 26 to the semiconductor switch 5 shown in FIG. 1. In this manner, the semiconductor switch (semiconductor switch 5C) is configured to include an over-temperature protection unit (protection circuit 26) that cuts off the semiconductor switch (semiconductor switch 5C) when the actual temperature detected by the actual temperature detection unit (temperature detection element 8) reaches the over-temperature threshold. By providing the protection circuit 26 to the semiconductor switch 5C, the power supplied by the semiconductor switch 5C to the load device 2 is immediately cut off when the actual temperature reaches the over-temperature threshold, and the operation of the load device 2 can be temporarily stopped. Thereafter, the operation of the load device 2 can be safely resumed in a state in which the power supplied to the load device 2 by the drive management unit 13 is limited.

[0077] As described above, the gate drive circuit 7 outputs an ON / OFF voltage (or current) to the gate terminal of the power semiconductor 6. The temperature detection element 8 detects the actual temperature of the power semiconductor 6. The temperature detection element 8 does not output the actual temperature information to the determination unit 12, but outputs the actual temperature information to the protection circuit . The protection circuit 26 sends a signal to the gate drive circuit 7 based on the temperature of the temperature detection element 8 to shut off the power semiconductor 6 .

[0078] A power supply input terminal of the semiconductor switch 5C is connected to the battery 4. An output terminal of the semiconductor switch 5C is connected to a power line 9a. The power line 9a is connected to a power supply input terminal of the load device 2.

[0079] The control unit 3B has a configuration in which an operation monitoring unit 27 is added to the control unit 3 shown in FIG. The temperature estimation unit 11 detects the power consumption of the semiconductor switch 5C based on the current of the semiconductor switch 5C detected based on the voltage of the resistor 24 and the voltage across the semiconductor switch 5C. The temperature estimation unit 11 then outputs to the determination unit 12 estimated temperature information 15 obtained by calculating the internal temperature of the semiconductor switch 5C based on the detected power consumption.

[0080] The estimated temperature information 15 is calculated using the ambient temperature detected by the temperature sensor 14 for detecting the ambient temperature of the semiconductor switch 5. The method in which the temperature estimation unit 11 estimates the internal temperature of the semiconductor switch 5 is the same as in the first embodiment.

[0081] The operation monitoring unit (operation monitoring unit 27) monitors the operation of the overtemperature protection unit (protection circuit 26) to cut off the semiconductor switch (semiconductor switch 5C), and when the semiconductor switch (semiconductor switch 5C) is cut off, outputs a cut-off operation detection result to the determination unit (determination unit 12). For example, the operation monitoring unit 27 has a function of monitoring an ON / OFF command transmitted from the drive management unit 13 of the control unit 3B to the semiconductor switch 5C and the output terminal voltage of the semiconductor switch 5C, and monitoring whether the protection circuit 26 has operated. Then, the operation monitoring unit 27 outputs a monitoring result of the operation of the protection circuit 26 to the determination unit 12.

[0082] The determination unit (determination unit 12) determines whether the semiconductor switch (semiconductor switch 5C) is in a poor heat dissipation state based on the shutoff operation detection result input from the operation monitoring unit (operation monitoring unit 27). At this time, the determination unit 12 can determine whether the semiconductor switch 5C is normal or abnormal based on the estimated temperature information 15 and the monitoring result of the operation monitoring unit 27. In this way, the controller 30C, by being provided with the operation monitoring unit 27, can indirectly determine that a heat dissipation defect has occurred in the semiconductor switch 5C based on the shutoff operation of the protection circuit 26. The method of determining whether the semiconductor switch 5C is normal or abnormal will be described in detail later.

[0083] The drive management unit 13 outputs an ON / OFF command for the semiconductor switch 5C in response to a drive command 17. This ON / OFF command is input to the gate drive circuit 7 of the semiconductor switch 5C, and controls the drive of the load device 2 through the power semiconductor 6. The method in which the drive management unit 13 receives an abnormality determination from the determination unit 12 and limits the drive of the load device 2 (output of an OFF command, method of lowering the carrier frequency in the PWM waveform, correction of the drive command 17) and the effects thereof are similar to those of the drive management unit 13 according to the first embodiment.

[0084] Next, a method of determining whether the semiconductor switch 5C is normal or abnormal in the determining unit 12 shown in FIG. 9 and an embodiment of the power management of the actuator will be described.

[0085] <Power control according to package state> Fig. 10 is a diagram showing the transition of the package state of the semiconductor switch 5C and the relationship between the operation monitoring state, the estimated temperature information, and the actuator power for each package state. In Fig. 10, the package state of the semiconductor switch 5C shown in Fig. 9 transitions in the order of a normal state to a state in which poor heat dissipation has occurred due to deterioration of the package or deterioration of the adhesive state of the printed circuit board 22. Fig. 10 shows the state of control according to this embodiment in each package state.

[0086] (Normal state) 10, when the package state is normal, the drive management unit 13 drives the semiconductor switch 5 in the normal mode. Furthermore, when the package state is normal, the power supplied to the actuator is controlled to be equal to or lower than a specified limit value so that the IPD estimated temperature is less than an over-temperature threshold (e.g., 150°C). The estimated temperature information obtained by the temperature estimation unit 11 is called the IPD estimated temperature. In the normal state, the operation monitoring unit 27 does not detect the operation of the protection circuit 26.

[0087] (Poor heat dissipation) When the deterioration state of the package of the semiconductor switch 5C changes from a normal state to a poor heat dissipation state, the temperature of the semiconductor switch 5C rises. Then, at the timing when the actual temperature reaches the overtemperature threshold, the protection circuit 26 provided inside the semiconductor switch 5C operates, and the protection circuit 26 outputs a cut-off command to the gate drive circuit 7. When the protection circuit 26 operates, the operation monitoring unit 27 detects the cut-off operation of the protection circuit 26 based on a change in current of the power line 9a. Then, the operation monitoring unit 27 outputs a detection result of the cut-off operation by the protection circuit 26 to the determination unit 12.

[0088] The determination unit 12 detects the temperature difference ΔT between the estimated temperature information estimated by the temperature estimation unit 11 at the timing detected by the operation monitoring unit 27 and the over-temperature threshold. The over-temperature threshold is the temperature at which the protection circuit 26 provided in the semiconductor switch 5C operates, and the over-temperature threshold can be known in advance as a design value. If the value obtained by adding the temperature difference ΔT to the IPD estimated temperature is equal to or greater than the over-temperature threshold, the drive management unit 13 switches to a power limiting mode in which the operation of the actuator is limited.

[0089] In the power limit mode, the drive management unit 13 outputs an ON / OFF command to the gate drive circuit 7. This limits the power supplied to the load device 2 via the semiconductor switch 5C. In addition, since the mode is changed to the power limit mode and the power supplied to the load device 2 from the semiconductor switch 5B is reduced, the IPD estimated temperature is lower than in the normal mode.

[0090] Although not shown, if the poor heat dissipation state continues and the poor heat dissipation state of the package of semiconductor switch 5C progresses, protection circuit 26 operates again and operation monitoring unit 27 detects the cut-off operation of protection circuit 26. In this case, determination unit 12 determines that the poor heat dissipation state of the package has progressed, and drive management unit 13 commands semiconductor switch 5C to stop operating. As a result, semiconductor switch 5C stops supplying power to load device 2.

[0091] With the configuration of the controller 30C described above, when the actual temperature of the semiconductor switch 5C reaches the overtemperature threshold, the protection circuit 26 operates, and the gate drive circuit 7 limits the power supplied from the power semiconductor 6 to the load device 2 at the timing when the protection circuit 26 operates. The operation monitoring unit 27 detects that the power supplied from the power semiconductor 6 to the load device 2 has been limited, and the determination unit 12 determines that the semiconductor switch 5C is no longer in a normal state. For this reason, the determination unit 12 can detect the deterioration state of the package of the semiconductor switch 5C without directly acquiring actual temperature information from the semiconductor switch 5C.

[0092] Then, the drive management unit 13 can continue the operation of the semiconductor switch 5C by appropriately limiting the power supplied to the load device 2 according to the temperature difference ΔT between the estimated temperature information at the time when the protection circuit 26 operates and the over-temperature threshold. That is, in this embodiment, the semiconductor switch 5C is once shut off and stops functioning due to an over-temperature, but the power is thereafter limited to an appropriate level, so that the operation of the semiconductor switch 5C can be continued. This makes it possible to prevent the temperature of the semiconductor switch 5C from rising again and causing the semiconductor switch 5C to repeatedly stop.

[0093] The operation monitoring unit 27 according to this embodiment detects whether the overtemperature protection function of the protection circuit 26 has been activated by comparing the ON / OFF signal input from the drive management unit 13 to the semiconductor switch 5C with the actual ON / OFF state of the semiconductor switch 5C. Here, the semiconductor switch 5C may have a function of outputting status information indicating that the overtemperature protection function of the protection circuit 26 has been activated to the determination unit 12 of the control unit 3B. Based on the status information input from the semiconductor switch 5C, the determination unit 12 determines that the semiconductor switch 5C is in an overtemperature state. Then, the drive management unit 13 can switch from the normal mode to the power limiting mode and continue the operation of the semiconductor switch 5C.

[0094] [Third embodiment] Next, a configuration example of a power supply system according to a third embodiment of the present invention will be described. In this embodiment, the operation of a controller that controls power supply to a plurality of load devices connected to one semiconductor switch will be described. FIG. 11 is a diagram showing an example of the configuration of a controller 30 in which a plurality of load devices 2(1) to 2(3) are connected to a semiconductor switch 5. In FIG.

[0095] The power supply system 1A includes a battery 4, a controller 30, and load devices 2(1) to 2(3). The configuration of the controller 30 is the same as that of the controller 30 according to the first embodiment described above. A plurality of load devices 2(1)-2(3) are connected to the controller 30. In the drawing, the load device 2(1) is described as "load device A", the load device 2(2) is described as "load device B", and the load device 2(3) is described as "load device C". In the following description, when there is no need to distinguish between the load devices 2(1)-2(3), they are referred to as the load devices 2.

[0096] In this manner, the management unit (drive management unit 13) is connected to a plurality of control targets (load devices 2(1) to 2(3)) to which power is supplied from the operation control unit (semiconductor switch 5). The drive management unit 13 and the load devices 2(1) to 2(3) are connected by a communication line 28. The communication line 28 may be digital communication such as CAN (Controller Area Network) or LIN (Local Interconnect Network), or analog transmission for transmitting a PWM signal, a voltage signal, or the like.

[0097] Power is supplied to the load devices 2(1)-2(3) via a semiconductor switch 5. The load devices 2(1)-2(3) receive operation commands for each of the load devices 2(1)-2(3) transmitted from the drive management unit 13 via a communication line 28, and operate accordingly.

[0098] The determination unit 12 of the controller 30 according to the third embodiment determines the deterioration state of the semiconductor switch 5 based on the actual temperature information and the estimated temperature information of the semiconductor switch 5, similarly to the determination unit 12 according to the first embodiment. Then, when the determination unit (determination unit 12) determines that the state of the operation control unit (semiconductor switch 5) has changed, the management unit (drive management unit 13) stops the power supplied from the operation control unit (semiconductor switch 5) to the control target (load device 2) with a low priority among the multiple control targets (load devices 2(1) to 2(3)). In this way, when the drive management unit 13 determines that the semiconductor switch 5 is in a deteriorated state, it stops the operation of any of the load devices 2(1) to 2(3) via the communication line 28. Preferably, the load devices 2(1) to 2(3) are set to a priority order according to the importance of their functions, and the power supply to the load device 2 with a low priority is stopped. Even if the load device 2 with a low priority stops, the load device 2 with a high priority continues to operate, so that the operation of the important load device 2 is prevented from immediately stopping.

[0099] In the power supply system 1A according to the third embodiment described above, a plurality of load devices 2(1)-2(3) are connected to one semiconductor switch 5, and the drive management unit 13 controls the amount of operation of the load device 2 via a communication line. When an abnormality occurs in the semiconductor switch 5, the determination unit 12 quantitatively detects the abnormal state of the semiconductor switch 5. Here, in the power supply system 1A, the drive management unit 13 corrects the amount of operation as the drive command 17 to a value to which a limit is applied, and transmits it to the load device 2 via the communication line. Therefore, the drive management unit 13 can control the operation of the load device 2 by directly switching the switch provided inside the load device 2 ON or OFF.

[0100] In this way, in the power supply system 1A, even if multiple load devices 2 are connected to the semiconductor switch 5, power supply is stopped to the load devices 2 whose operation is turned off, thereby suppressing the power supplied to all of the load devices 2. As a result, the current flowing through the semiconductor switch 5 is reduced, making it possible to prevent failure or stoppage due to overtemperature of the semiconductor switch 5. Also, the drive management unit 13 can maintain control while maintaining the operation of the load devices 2 having functions with high priority by continuing the power supply to the load devices 2 with high priority.

[0101] [Fourth embodiment] Next, a configuration example of a power supply system according to a fourth embodiment of the present invention will be described. In this embodiment, the operation of a controller that controls power supply to a plurality of load devices 2 connected to a plurality of semiconductor switches in a one-to-one relationship will be described. FIG. 12 is a diagram showing an example of the configuration of a controller 30D in which a plurality of semiconductor switches 5D are branch-connected downstream of a semiconductor switch 5. In FIG.

[0102] The power supply system 1A has the same configuration as the power supply system 1A shown in FIG. 11, but the controller 30 is replaced with a controller 30D. The controller 30D includes a plurality of semiconductor switches 5D(1)-5D(3) in addition to the components of the controller 30 according to the first embodiment. The controller 30D includes a plurality of second operation control sections (semiconductor switches 5D(1)-5D(3)) that are provided for a plurality of control targets (load devices 2(1)-2(3)) and supply power supplied from the operation control section (semiconductor switch 5) to the control targets (load devices 2(1)-2(3)). In the following description, when the semiconductor switches 5D(1)-5D(3) are not to be distinguished from one another, they are referred to as semiconductor switches 5D.

[0103] A plurality of semiconductor switches 5D(1) to 5D(3) are connected in a branched manner to the semiconductor switch 5. Load devices 2(1) to 2(3) are connected to the plurality of semiconductor switches 5D(1) to 5D(3) in a one-to-one relationship. Power is supplied to the load devices 2(1) to 2(3) via the semiconductor switches 5D(1) to 5D(3) connected thereto, respectively.

[0104] An ON / OFF command is input individually to each gate of semiconductor switches 5D(1)-5D(3) from drive management unit 13. Semiconductor switches 5D(1)-5D(3) supply power to load devices 2(1)-2(3) connected thereto in response to the ON / OFF command. Load devices 2(1)-2(3) are driven and controlled by semiconductor switches 5D(1)-5D(3) connected thereto.

[0105] As in the first embodiment, the determination unit 12 determines the degradation state of the semiconductor switch 5 based on the actual temperature information and the estimated temperature information of the semiconductor switch 5. Then, when the management unit (drive management unit 13) limits the power supplied to the control target (load device 2) by the operation control unit (semiconductor switch 5D) based on the determination result, the management unit (drive management unit 13) stops the power supplied to the control target (load device 2) by the second operation control unit (semiconductor switch 5D) connected to the control target (load device 2) with a low priority among the multiple control targets (load devices 2). When it is determined that the semiconductor switch 5 is in a degraded state, the drive management unit 13 shuts off any one of the semiconductor switches 5D(1) to 5D(3) and stops the operation of any one of the load devices 2(1) to 2(3). Preferably, the drive management unit 13 sets priorities for the load devices 2(1) to 2(3) according to the importance of their functions, and stops them in order of lower priority. Even if a load device 2 with a low priority stops, a load device 2 with a high priority continues to operate, so that an immediate stop of the operation of an important load device 2 can be avoided.

[0106] In the power supply system 1A according to the fourth embodiment described above, a plurality of load devices 2(1)-2(3) are connected to one semiconductor switch 5 via semiconductor switches 5D(1)-5D(3), respectively. When an abnormality occurs in the semiconductor switch 5, the determination unit 12 quantitatively detects the abnormal state, so that the drive management unit 13 can perform control while maintaining high-priority functions. In particular, the determination unit 12 can detect an abnormal state in a semiconductor switch through which a large current flows and which is in a severe temperature environment, among the plurality of semiconductor switches 5, 5D(1)-5D(3) provided in the controller 30.

[0107] [Fifth embodiment] Next, a configuration example of a power supply system according to a fifth embodiment of the present invention will be described. In this embodiment, the operation of a controller that controls power supply to a plurality of load devices connected to a plurality of semiconductor switches in a one-to-one relationship will be described. FIG. 13 is a diagram showing an example of the configuration of a controller 30E including a plurality of semiconductor switches 5. As shown in FIG.

[0108] The power supply system 1A shown in FIG. 13 has the same configuration as the power supply system 1A shown in FIG. 11, but the controller 30 is replaced with a controller 30E. In addition to the control unit 3 and the temperature sensor 14, the controller 30E includes a plurality of semiconductor switches 5(1)-5(3), a plurality of shunt resistors 10(1)-10(3), and a plurality of multiplexers 29(1) and 29(2).

[0109] A plurality of shunt resistors 10(1)-10(3) are connected between the battery 4 and the plurality of semiconductor switches 5(1)-5(3), respectively. The plurality of semiconductor switches 5(1)-5(3) are connected in a one-to-one relationship to the load devices 2(1)-2(3). Power is supplied to the load devices 2(1)-2(3) via the semiconductor switches 5(1)-5(3) connected thereto. In the following description, when there is no need to distinguish between the semiconductor switches 5(1)-5(3), they are referred to as semiconductor switches 5.

[0110] A plurality of control targets (load devices 2(1)-2(3)) to which power is supplied from a plurality of operation control units (semiconductor switches 5(1)-5(3)) are connected to the management unit (drive management unit 13). The drive management unit 13 can select a specific semiconductor switch 5 and limit the power supplied by this semiconductor switch 5. For example, an ON / OFF command is input from the drive management unit 13 to each gate of the semiconductor switches 5(1)-5(3). The semiconductor switches 5(1)-5(3) supply power to the connected load devices 2(1)-2(3) in response to the ON / OFF command. The load devices 2(1)-2(3) are drive-controlled by the connected semiconductor switches 5(1)-5(3).

[0111] As in the first embodiment, the determination unit 12 determines the degradation state of the semiconductor switches 5(1)-5(3) based on the actual temperature information and estimated temperature information of the semiconductor switches 5(1)-5(3). When it is determined that any of the semiconductor switches 5(1)-5(3) is in a degraded state, the drive management unit 13 instructs to cut off the power supply to any of the semiconductor switches 5(1)-5(3) determined to be in a degraded state, and stops the operation of any of the load devices 2(1)-2(3). Preferably, the drive management unit 13 sets priorities for the load devices 2(1)-2(3) according to the importance of their functions, and stops them starting with those with the lowest priorities.

[0112] Shunt resistor 10(1) detects the current of semiconductor switch 5(1). Similarly, shunt resistor 10(2) detects the current of semiconductor switch 5(2), and shunt resistor 10(3) detects the current of semiconductor switch 5(3).

[0113] In this embodiment, current detection signals are output from multiple shunt resistors 10(1)-10(3), and signals indicative of voltage drops across multiple semiconductor switches 5(1)-5(3) and actual temperature information 16 from multiple temperature detection elements 8 are output. The current detection signals and the signals indicative of voltage drops are input to multiplexer 29(1). The actual temperature information 16 is input to multiplexer 29(2).

[0114] The first selection unit (multiplexer 29(1)) selects current detection signals detected by the multiple current detection units (shunt resistors 10(1)-10(3)) connected to the multiple control targets (load devices 2(1)-2(3)) for each of the multiple current detection units (shunt resistors 10(1)-10(3)) and outputs the selected current detection signal to the temperature estimation unit (temperature estimation unit 11). The controller 30E, which includes the multiplexer 29(1), can take in signals input from the multiple semiconductor switches 5(1)-5(3) through a single interface. Here, a selection signal for selecting a signal of a required channel is input from the temperature estimation unit 11 to the multiplexer 29(1). The multiplexer 29(1) outputs the signal of the channel selected based on the selection signal to the temperature estimation unit 11. Then, the temperature estimation unit 11 outputs estimated temperature information 15 to the determination unit 12 based on the input channel signal and the ambient temperatures of the semiconductor switches 5(1) to 5(3) input from the temperature sensor .

[0115] The second selection unit (multiplexer 29(2)) selects actual temperature information of the actual temperatures detected by the actual temperature detection units (temperature detection elements 8) of the multiple operation control units (semiconductor switches 5) connected to the multiple control targets (load devices 2) for each of the multiple operation control units (semiconductor switches 5(1) to 5(3)), and outputs the information to the judgment unit (judgment unit 12). By including the multiplexer 29(2), the controller 30E can take in signals input from the temperature detection elements 8 of the multiple semiconductor switches 5(1) to 5(3) through a single interface. Here, the multiplexer 29(2) selects the actual temperature information 16 of the channel selected by the multiplexer 29(1), and outputs the information to the judgment unit 12.

[0116] The determination unit 12 determines whether each of the semiconductor switches 5(1) to 5(3) is normal or abnormal based on the estimated temperature information 15 input from the temperature estimation unit 11 and the actual temperature information 16 input from the multiplexer 29(2). Then, the determination unit 12 outputs the determination result of the semiconductor switch 5 determined to be abnormal to the drive management unit 13. The drive management unit 13 limits the power supplied to the load device 2 by the semiconductor switch 5 determined to be abnormal. Here, when the determination unit (determination unit 12) determines that the state of the operation control unit (semiconductor switch 5) has changed, the management unit (drive management unit 13) stops the power supplied from the operation control unit (semiconductor switch 5) to the control target (load device 2) with a low priority among the multiple control targets (load devices 2). Even if the load device 2 with a low priority stops, the load device 2 with a high priority continues to operate, so that the operation of the important load device 2 is prevented from immediately stopping.

[0117] In the power supply system 1A according to the fifth embodiment described above, a plurality of load devices 2(1)-2(3) are connected to semiconductor switches 5(1)-5(3), respectively. The control unit 3 receives the signals output from the semiconductor switches 5(1)-5(3) selected by the multiplexers 29(1)-29(2) and the actual temperature information 16, and determines an abnormal state of the semiconductor switch 5. By providing the multiplexers 29(1)-29(2) in this manner, the number of input interfaces of the control unit 3 can be reduced even if the number of semiconductor switches 5 increases.

[0118] Furthermore, when an abnormality occurs in any of the semiconductor switches 5(1) to 5(3), the determination unit 12 can identify the semiconductor switch 5 in which the abnormality occurs. Therefore, the drive management unit 13 can output an OFF command to the semiconductor switch 5 in which the abnormality occurs, while outputting an ON / OFF command to the other semiconductor switches 5. Therefore, the load device 2 connected to the semiconductor switch 5 in which no abnormal state is detected can continue to operate.

[0119] [Sixth embodiment] In the power supply system 1A according to the fifth embodiment described above, the semiconductor switch 5 that turns on / off the power supply of the actuator has been described as the semiconductor element. The present invention can also be applied to other semiconductor elements such as switching elements used in inverters that control the drive torque of microcomputers and motors, and switching elements used in DC / DC converters. Therefore, a configuration example of a power supply system according to a sixth embodiment will be described with reference to FIG. FIG. 14 is a schematic configuration diagram of a power supply system 1B according to the sixth embodiment.

[0120] The power supply system 1B is an application of the present invention to a microcomputer 50. The power supply system 1B includes a power supply circuit 40, a shunt resistor 41, input devices 42(1)-42(3), output devices 43(1)-43(3), and the microcomputer 50.

[0121] Power is input from the power supply circuit 40 to the microcomputer 50. A shunt resistor 41 disposed between the power supply circuit 40 and the microcomputer 50 outputs a detected current to the microcomputer 50. The shunt resistor 41 may be configured to be built into the microcomputer 50.

[0122] The microcomputer (microcomputer 50) includes an actual temperature detection unit (temperature sensor 53), a temperature estimation unit (temperature estimation unit 52), a determination unit (determination unit 55), a management unit (computation amount management unit 56), an operation control unit (operation control unit 59), a control calculation unit (control calculation unit 58), an input interface (input interface 57), and an output interface (output interface 60). Furthermore, the microcomputer 50 includes A / D conversion units 51 and 54.

[0123] To the input interface 57, input signals are input from the input devices 42(1) to 42(3) such as sensors and switches.

[0124] The controlled object according to the sixth embodiment is a control calculation unit (control calculation unit 58) that performs a predetermined calculation process based on input data input from an input device (input devices 42(1)-42(3)) via an input interface (input interface 57) and outputs the result of the calculation to an output device (output devices 43(1)-43(3)) via an output interface (output interface 60). The control calculation unit 58 performs a predetermined calculation process corresponding to the input device 42 based on an input signal received via the input interface 57. Then, the control calculation unit 58 outputs the result of the calculation process to the output interface 60. Here, the control calculation unit 58 includes an operation control unit 59 that limits some of the functions of the control calculation unit 58 based on an instruction signal input from the calculation amount management unit 56. This operation control unit (operation control unit 59) controls the amount of calculation of the calculation process performed in the control calculation unit (control calculation unit 58).

[0125] The output interface 60 outputs output signals to the output devices 43(1) to 43(3) such as motors and heaters based on the results of the calculation processing.

[0126] A current detection signal of the current detected by the shunt resistor 41 is input to an A / D conversion unit 51. The A / D conversion unit 51 converts the analog current detection signal into digital data and outputs the digital current detection signal to a temperature estimation unit 52. The temperature estimation unit (temperature estimation unit 52) ​​estimates the internal temperature of the control calculation unit (control calculation unit 58) based on a current detection signal input from a current detection unit (shunt resistor 41) that detects the current supplied from the power supply unit (power supply circuit 40) to the operation control unit (operation control unit 59) and the thermal resistance and heat capacity of the components of the operation control unit (operation control unit 59). At this time, the temperature estimation unit 52 estimates the temperature around the microcomputer 52 based on the current detection signal, and outputs it to the determination unit 55 as estimated temperature information. At this time, the temperature estimation unit 52 calculates the estimated temperature information from the power consumption of the microcomputer 50 and a heat dissipation model based on the package and mounting form of the microcomputer 50.

[0127] Meanwhile, actual temperature information measured by a temperature sensor 53 provided inside the microcomputer 50 is converted into digital data by an A / D conversion section 54 and output to a determination section 55 as actual temperature information.

[0128] The determination unit (determination unit 55) compares the temperature difference added to the estimated temperature with an over-temperature threshold value to determine whether the state of the operation control unit (operation control unit 59) is normal or poor heat dissipation. For example, the determination unit 55 compares the estimated temperature information with the actual temperature information, similar to the determination unit 12 according to the above-described first embodiment. Then, it determines whether the package of the microcomputer 50 has deteriorated, that is, whether the microcomputer 50 is in an abnormal state.

[0129] The heat generated by the control calculation unit 58 changes depending on the amount of calculation in the calculation process. Therefore, the management unit (calculation amount management unit 56) instructs the operation control unit (operation control unit 59) to limit the amount of calculation in the calculation process based on the result of the judgment by the judgment unit (judgment unit 55). Here, when the management unit (calculation amount management unit 56) judges that the state of the operation control unit (operation control unit 59) is a poor heat dissipation state, it instructs to limit the amount of calculation in the calculation process performed by the control calculation unit (control calculation unit 58) more than in the normal state. When the judgment unit 55 judges that the microcomputer 50 is in the normal state, the calculation amount management unit 56 does not limit the amount of calculation by the control calculation unit 58.

[0130] On the other hand, when the determination unit 55 determines that the microcomputer 50 is in a deteriorated state, the calculation amount management unit 56 instructs the control calculation unit 58 to limit the amount of calculation. At this time, the calculation amount management unit 56 sets priorities for the calculation processes of the control calculation unit 58, and instructs the operation control unit 59 to limit the amount of calculation so as to stop calculation processes with low priorities.

[0131] The operation control unit (operation control unit 59) limits the amount of calculation of the calculation process performed by the control calculation unit (control calculation unit 58) based on the instruction. Since the calculation process with a low priority is stopped, important control functions of the microcomputer 50 are maintained. In this way, the operation control unit 59 limits the amount of calculation of the control calculation unit 58 and suppresses the power consumption of the control calculation unit 58, thereby making it possible to avoid stopping the microcomputer 50. The management unit (calculation amount management unit 56) further issues an instruction to stop the calculation process by the control calculation unit (control calculation unit 58) when it is determined that poor heat dissipation has progressed. In this case, the operation control unit 59 safely stops the calculation process of the control calculation unit 58.

[0132] The power supply system according to each of the above-described embodiments may be used, for example, in an engine ECU or a powertrain integrated ECU of a hybrid vehicle. The power supply system may also be used, for example, in a zone integrated ECU in zone architecture of an electric / electronic system (E / E (Electrical / Electronic) system) of a vehicle.

[0133] Moreover, the controller according to each of the above-mentioned embodiments may be applied to a calibration method in a mass production line. In a mass production line, it is important to make the estimated temperature information of the semiconductor switch, which is estimated based on the thermal model shown in Fig. 3, coincide with the actual temperature information. Therefore, if there is a discrepancy between the temperature estimated by the controller according to each of the embodiments and the actual temperature obtained by actual measurement, it is possible to perform calibration such as correcting the thermal model so that the estimated temperature coincides with the actual temperature.

[0134] Incidentally, the present invention is not limited to the above-described embodiments, and it goes without saying that various other applications and modifications are possible without departing from the gist of the present invention as set forth in the claims. For example, the above-mentioned embodiments have described the configuration of the device and system in detail and specifically in order to explain the present invention in an easily understandable manner, and are not necessarily limited to those including all of the configurations described. In addition, it is possible to replace part of the configuration of the embodiments described here with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations. In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are connected to each other. [Explanation of symbols]

[0135] 1...power supply system, 2...load device, 3...control unit, 4...battery, 5...semiconductor switch, 6...power semiconductor, 7...gate drive circuit, 8...temperature detection element, 9a, 9b...power line, 10...shunt resistor, 11...temperature estimation unit, 12...judgment unit, 13...drive management unit, 14...temperature sensor, 15...estimated temperature information, 16...actual temperature information, 17...drive command, 30...controller

Claims

1. an operation control unit that controls an operation of a control target to which power is supplied from a power supply unit; a current detection unit that detects a current supplied from the power supply unit to the operation control unit; an actual temperature detection unit that detects an internal temperature of the operation control unit as an actual temperature; a temperature estimator that estimates the internal temperature as an estimated temperature based on a current detection signal output from the current detector, the current being a current supplied to the operation control unit, and thermal resistances and heat capacities of components of the operation control unit; a determination unit which provides a first threshold and a second threshold for comparing a temperature difference between the actual temperature and the estimated temperature, and outputs a determination result in which the state of the operation control unit is normal when the actual temperature is less than an overtemperature threshold and the temperature difference is less than the first threshold, the state of the operation control unit is a poor heat dissipation state when the temperature difference is equal to or greater than the first threshold, and the state of the operation control unit is a state in which the poor heat dissipation state has progressed when the temperature difference is equal to or greater than the second threshold, and which determines which component has an abnormality based on a change in the temperature difference for each component of the operation control unit after power is applied to the operation control unit; a management unit that, when the determination result that the state of the operation control unit is the poor heat dissipation state is obtained, limits the power supplied by the operation control unit to the controlled object to a level lower than the power supplied in the normal state, and further, when it is determined that the poor heat dissipation state has progressed, stops the power supplied by the operation control unit to the controlled object, thereby managing the operation of the operation control unit so that the actual temperature becomes less than the overtemperature threshold value, and continues the operation of the operation control unit; and notifies the state of the operation control unit and the determination result of the component member in which an abnormality has occurred before the operation control unit stops the power supplied to the controlled object. Vehicle control device.

2. The controlled object is a load device that repeats ON and OFF operations for the operation control unit after the start of energization, The determination unit outputs the determination result, which determines whether the first component is a first component in which, after the start of energization, a temperature difference occurs between the actual temperature and the estimated temperature when the operation control unit is turned on and no temperature difference occurs between the actual temperature and the estimated temperature when the operation control unit is turned off, and whether the second component is a first component in which, after the start of energization, a temperature difference occurs between the actual temperature and the estimated temperature when the operation control unit is turned on and off over time. The vehicle control device according to claim 1.

3. the operation control unit is a semiconductor switch that controls power supplied to the controlled object, The determination unit determines which of the components of the semiconductor switch has an abnormality based on a change in the temperature difference between the components of the semiconductor switch after a current is applied to the semiconductor switch. The vehicle control device according to claim 1 or 2.

4. The current detection unit is a shunt resistor connected in series to the semiconductor switch, The temperature estimator detects a current supplied to the semiconductor switch based on a voltage across the shunt resistor. The vehicle control device according to claim 3.

5. The shunt resistor is provided between the power supply unit and the semiconductor switch. The vehicle control device according to claim 4.

6. The actual temperature detection unit is any one of a diode element, a resistor element, and a thermistor element provided on a semiconductor substrate that constitutes the semiconductor switch. The vehicle control device according to claim 5.

7. The semiconductor switch has a current sense MOS FET as the current detection unit for detecting a current supplied to the semiconductor switch. The vehicle control device according to claim 3.

8. the semiconductor switch has a current sense MOS FET as the current detection unit for detecting a current supplied to the semiconductor switch, The actual temperature detection unit outputs actual temperature information of the actual temperature calculated based on a change in the on-resistance of the current sense MOS FET to the determination unit. The vehicle control device according to claim 3.

9. the actual temperature detection unit is any one of a diode element, a resistor element, and a thermistor element provided on a semiconductor substrate constituting the semiconductor switch, the semiconductor switch has an over-temperature protection unit that turns off the semiconductor switch when the actual temperature detected by the actual temperature detection unit reaches an over-temperature threshold; an operation monitoring unit that monitors an operation of the overtemperature protection unit to cut off the semiconductor switch, and when the semiconductor switch is cut off, outputs a cut-off operation detection result to the determination unit; The determination unit determines a heat dissipation failure state of the semiconductor switch based on the interruption operation detection result input from the operation monitoring unit. The vehicle control device according to claim 3.

10. a plurality of control targets to which power is supplied from the operation control unit are connected to the management unit; When the determination unit determines that the state of the operation control unit has changed, the management unit stops power supplied from the operation control unit to a control target having a low priority among the plurality of control targets. The vehicle control device according to claim 4.

11. a plurality of second operation control units provided for the plurality of control targets, the second operation control units supplying the power supplied from the operation control unit to the control targets; When limiting the power supplied by the operation control unit to the control target based on the determination result, the management unit stops the power supplied by the second operation control unit to the control target, for the second operation control unit connected to the control target having a lower priority among the plurality of control targets. The vehicle control device according to claim 4.

12. a plurality of control targets to which power is supplied from a plurality of the operation control units are connected to the management unit; a first selection unit that selects the current detection signals detected by the current detection units connected to the respective control targets for each of the current detection units, and outputs the selected current detection signals to the temperature estimation unit; a second selection unit that selects, for each of the plurality of operation control units, actual temperature information of the actual temperatures detected by the actual temperature detection units of the plurality of operation control units connected to each of the plurality of control targets, and outputs the selected actual temperature information to the determination unit; When the determination unit determines that the state of the operation control unit has changed, the management unit stops power supplied from the operation control unit to a control target having a low priority among the plurality of control targets. The vehicle control device according to claim 4.

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