JP5749285B2 - Power supply device - Google Patents

Description

  The present invention relates to a power supply device provided with a protection means for protecting a device from an overcurrent or an excessive temperature rise.

  In a power supply system such as a vehicle, a fuse is appropriately disposed in the power supply line in order to prevent the load from being damaged or the power supply line (electric wire) from being burned out due to the occurrence of an abnormal current such as an overcurrent. In recent years, semiconductor switches having both relay and fuse functions have been used. A semiconductor switch is known that has a self-protection function that monitors and protects a phenomenon that causes damage to the semiconductor switch, such as its own overcurrent and overheating.

  By the way, with the increase in functionality and multifunction of vehicles, in recent years, electrical loads mounted on vehicles have increased significantly, and along with this, the number of semiconductor switches used in power supply systems tends to increase. For this reason, it has become difficult to individually manage a plurality of semiconductor switches, and a technique for managing them collectively has been developed. As an example, in Cited Document 1, a monitoring ECU (load current monitoring unit) that manages and manages a plurality of load lines (power supply lines) is provided. It has become.

JP 2009-11040 A

  However, a configuration in which a semiconductor switch provided in a plurality of power supply lines is managed by one CPU or ASIC such as a monitoring unit or a control unit has an advantage of suppressing cost increase, but an abnormality occurs in the CPU. All semiconductor switches cannot be monitored and controlled, and there is a high possibility that the safety of the system cannot be ensured. In particular, in the power supply system of a vehicle, when power supply to an important load such as a headlamp or an engine system is stopped, there arises a problem that it is impossible to maintain safe traveling of the vehicle.

  In addition, the semiconductor switch has a self-protection function for protecting itself, but the semiconductor switch cannot accurately protect against overcurrent of the power supply line (wire) to which the semiconductor switch is connected. In some cases, it may be configured to complement. In particular, in the protection characteristic region for the purpose of protecting the electric wire, when the accuracy of the interruption characteristic against the overcurrent is low, it is necessary to provide a margin for the applied electric wire size. In order to perform a design with the size of the applied electric wire being suppressed as much as possible, it is required that the interruption characteristic against overcurrent is highly accurate.

As described above, when the CPU or the like supplements the protection against the overcurrent of the power supply line (electric wire), if an abnormality occurs in the CPU, the power supply line cannot be protected even if the power supply is continued. . However, abnormalities such as CPU abnormalities (failures) and occurrences of abnormal events such as overcurrents are often caused by troubles such as vehicle accidents and can occur simultaneously. It is necessary to protect the line (electric wire).
Therefore, conventionally, one of a plurality of semiconductor switches controlled and managed by the central control unit cannot be applied to a power supply line to an important load, and its application range is restricted. There was a problem.

  The present invention has been made to solve these problems. The semiconductor switch and the power supply line are maintained while maintaining the operation state of the semiconductor switch connected to a specific load so that the target system is on the safe side. It is an object of the present invention to provide a power supply device capable of protecting both of them with an inexpensive configuration.

  A first aspect of the power supply apparatus of the present invention is provided in a power supply line for supplying power from a power supply to a load to turn on / off an energizing current and to generate an overcurrent based on one or more overcurrent protection characteristics. A semiconductor switch having a self-protection means for monitoring, a control section for controlling one or more of the semiconductor switches and having a monitoring / protection means for monitoring and protecting the semiconductor switch and the power supply line; and an operation of the control section. A monitoring unit for monitoring, and a protection characteristic adjusting unit for adjusting a limit value for monitoring an overcurrent of the self-protecting means when an abnormality of the control unit is detected by the monitoring unit. And

  According to another aspect of the power supply apparatus of the present invention, the protection characteristic adjustment unit adjusts a limit value for monitoring the overcurrent, and the overcurrent protection characteristic for the semiconductor switch and electric wire smoke for the power supply line The threshold for overcurrent is adjusted so as to satisfy both of the characteristics.

  According to another aspect of the power supply apparatus of the present invention, the protection characteristic adjustment unit adjusts a limit value for monitoring the overcurrent, and the overcurrent protection characteristic for the semiconductor switch and electric wire smoke for the power supply line The energization allowable time for the energization current of the semiconductor switch is adjusted so as to satisfy both of the characteristics.

  According to another aspect of the power supply apparatus of the present invention, the power supply device further includes an abnormality control unit that outputs a predetermined drive signal to the semiconductor switch when the monitoring unit detects an abnormality of the control unit. .

  In another aspect of the power supply apparatus of the present invention, the abnormality control unit outputs a pulse signal that repeatedly turns on and off at a predetermined cycle as the drive signal.

  In another aspect of the power supply apparatus of the present invention, the monitoring unit monitors the operation of the control unit using a predetermined clock pulse, and the abnormal time control unit receives the clock pulse from the monitoring unit. The pulse signal is generated by inputting.

  Another aspect of the power supply apparatus of the present invention is characterized in that the protection characteristic adjusting unit adjusts at least a threshold for a short-term overcurrent and a threshold for a long-term overcurrent.

  According to the present invention, the power supply capable of protecting both the semiconductor switch and the power supply line while maintaining the operation state of the semiconductor switch connected to the specific load so that the target system is on the safe side. It is possible to provide the apparatus with an inexpensive configuration.

It is a block diagram which shows the structure of the power supply device of 1st Embodiment of this invention. It is a graph which shows an example of the overcurrent protection characteristic of a semiconductor switch, and the electric wire smoke generation characteristic of an electric power supply line. It is a graph which shows an example of the threshold value which can monitor both an overcurrent protection characteristic and an electric wire smoke generation characteristic. It is a block diagram which shows the structure of the power supply apparatus of 2nd Embodiment of this invention. It is a block diagram which shows the structure of the power supply device of 3rd Embodiment of this invention.

  A power supply device according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description.

(First embodiment)
A power supply apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of a power supply apparatus 100 according to the present embodiment. The power supply device 100 controls power supply to each load 20 and monitors the power supply system in a power supply system that supplies power to each load 20 via the power supply line (electric wire) 11 from the power supply 10. It has a function to protect this when there is an abnormality.

  The power supply apparatus 100 according to the present embodiment controls a semiconductor switch 110 for turning on / off power supply from the power supply 10 to the load 20, and controls one or more semiconductor switches 110 and is connected to each semiconductor switch 110. The control unit 120 includes a CPU that monitors and protects each power supply line 11 and a monitoring unit 130 that monitors the operation of the control unit 120. Further, the power supply apparatus 100 may include a communication unit 140 for transmitting / receiving control information to / from another control system.

  The control unit 120 inputs an external signal 30 as a request signal from the outside for each semiconductor switch 110. When the controller 120 receives the external signal 30 for turning on the semiconductor switch 110, the controller 120 outputs a drive signal 31 for turning on the semiconductor switch 110 requested to be turned on.

  The control unit 120 also includes monitoring / protecting means 121 that monitors and protects the plurality of semiconductor switches 110 and the power supply line 11. The semiconductor switch 110 and the power supply line 11 are respectively provided with restrictions on overcurrent, and the monitoring / protecting means 121 monitors both of them. As a restriction on overcurrent, overcurrent protection characteristics are set for the semiconductor switch 110. The electric power supply line 11 is provided with electric wire smoke generation characteristics for preventing the electric wire from overheating and generating smoke. The control unit 120 can detect the current passing through the semiconductor switch 110 with high accuracy, and can monitor the overcurrent with high accuracy based on this.

  An example of the overcurrent protection characteristic of the semiconductor switch 110 and the electric wire smoke generation characteristic of the power supply line 11 are shown in FIG. In FIG. 2, the horizontal axis represents time, the vertical axis represents current, and the overcurrent protection characteristic and the electric wire smoke generation characteristic are represented by symbols C1 and C2, respectively. The overcurrent protection characteristics and the electric wire smoke characteristics monitored by the monitoring / protection means 121 are not limited to one each and may be two or more.

  The overcurrent protection characteristic C1, which is a limitation on the overcurrent of the semiconductor switch 110, allows a relatively large current to flow in a short period. However, the current value that can flow for a long period of time decreases as the period increases. It is shown that. In addition, the electric wire smoke characteristics C2, which is a restriction for preventing smoke from the power supply line 11, can flow a large current in a short period, but the current value is drastically decreased as the current flow period becomes longer. Indicates that it is necessary. The characteristic against overcurrent shown in FIG. 2 indicates that overcurrent protection characteristic C1 is an upper limit of allowable current for a short period, and electric wire smoke generation characteristic C2 is an upper limit for a long period.

  In order to easily monitor and protect the overcurrent of the semiconductor switch 110, for example, instead of the overcurrent protection characteristic C1 shown in FIG. 1 (threshold value I1) and a threshold value (second threshold value I2) for an overcurrent for a long period (greater than the first period T1) may be monitored. Similarly, the electric wire smoke generation characteristic C2 may be monitored by setting a threshold value (third threshold value I3) for a current value after a predetermined period (second period T2), for example.

  The monitoring / protection means 121 of the control unit 120 monitors and protects both the plurality of semiconductor switches 110 and the respective power supply lines 11, and monitors the respective overcurrent protection characteristics C1 and the wire smoke generation characteristics C2. . When the monitoring / protection means 121 detects an abnormality exceeding the limit based on the overcurrent protection characteristic C1 or the wire smoke generation characteristic C2, the limit is exceeded by turning off the semiconductor switch 110 to cut off the current. The semiconductor switch 110 or the power supply line 11 can be protected.

  The semiconductor switch 110 performs an operation of turning on / off the current to the load 20 in accordance with the drive signal 31 from the control unit 120, and has a self-protecting means 111 for protecting the switch itself. The self-protecting means 111 monitors the overcurrent protection characteristic C1 shown in FIG. 2 similarly to the monitoring / protection means 121 of the control unit 120, and detects an overcurrent that deviates from the limit based on the overcurrent protection characteristic C1. Then, the semiconductor switch 110 itself protects by turning off the current. As the monitoring for the overcurrent protection characteristic C1, the threshold for the overcurrent in the short period (below the first period T1) described above (first threshold I1) and the threshold for the overcurrent in the long period (over the first period T1). You may carry out using (2nd threshold value I2).

  Since the control unit 120 controls the plurality of semiconductor switches 110, if the control unit 120 does not operate normally due to some malfunction, there is a possibility that the power supply to all loads is stopped and the system is stopped. is there. Therefore, in the power supply apparatus 100 of the present embodiment, when an abnormality of the control unit 120 is detected, the power supply to the load 20 having at least an important function is continued without exceeding the limit on the overcurrent. In addition, a protection characteristic adjusting unit 131 is provided. As the load 20 having an important function, for example, an electric device mounted on a vehicle includes a headlamp and an engine system.

  An abnormality in the control unit 120 is detected by the monitoring unit 130. The monitoring unit 130 periodically inputs a specified signal from the control unit 120 as in the configuration of a watch dog (WD), for example, and when the specified signal is not input, the control unit 120 is abnormal. Judgment can be made. When the monitoring unit 130 determines that the control unit 120 is abnormal, for example, the monitoring unit 130 outputs a reset signal (abnormality determination signal) 32 to the control unit 120. The control unit 120 that receives the reset signal 32 from the monitoring unit 130 is reset to a predetermined initial state, for example.

  The semiconductor switch 110 can monitor and protect the overcurrent protection characteristic C1 by the self-protection means 111, but cannot monitor and protect the electric wire smoke generation characteristic C2 that is a limitation on the power supply line 11. Since the wire smoke characteristics C2 are monitored and protected by the control unit 120, if the control unit 120 becomes abnormal, the wire smoke characteristics C2 cannot be monitored and protected. Therefore, when the control unit 120 becomes abnormal, conventionally, it has been necessary to turn off all the semiconductor switches 110 connected to the control unit 120.

  In the power supply apparatus 100 of this embodiment, when an abnormality of the control unit 120 is detected, a predetermined adjustment signal 33 is output from the protection characteristic adjustment unit 131 to the semiconductor switch 110. When the adjustment signal 33 is input from the protection characteristic adjustment unit 131, the semiconductor switch 110 maintains the ON state and enables the self-protection means 111 to monitor and protect both the overcurrent protection characteristic C1 and the wire smoke generation characteristic C2. . Further, when the semiconductor switch 110 is in the off state, the off state is maintained.

  The self-protecting means 111 normally has an overcurrent protection characteristic C1 for the energization current of the semiconductor switch 110 set as a monitoring set value. When the adjustment signal 33 is input from the protection characteristic adjustment unit 131, the self-protection means 111 uses this. The setting value is changed so that both the overcurrent protection characteristic C1 and the electric wire smoke generation characteristic C2 can be monitored.

  As shown in FIG. 2, when a predetermined current is passed, the overcurrent protection characteristic C1 becomes a limit value for the overcurrent in a short period, but the wire smoke generation characteristic C2 becomes a limit value in a long period. Therefore, in the present embodiment, for example, a setting value of C3 shown in FIG. 3 is used in the self-protecting means 111 as a setting value that can monitor both the overcurrent protection characteristic C1 and the electric wire smoke generation characteristic C2. Thereby, both the semiconductor switch 110 and the power supply line 11 can be monitored.

  Instead of the setting value C3 shown in FIG. 3, the fourth threshold I4 and the fourth threshold I4 for the overcurrent shown in FIG. I5 of 5 may be used. That is, I4 is used as the overcurrent threshold until the energization time T3, and I5 is used as the overcurrent threshold when the energization time exceeds T3. Thereby, the overcurrent monitoring by the self-protecting means 111 can be simplified.

  As another setting value for monitoring and protection of the self-protecting means 111 when an abnormality of the control unit 120 is detected, the energization is performed from, for example, the setting value C3 shown in FIG. 3 according to the magnitude of the energizing current of the semiconductor switch 110. An allowable time (hereinafter referred to as overcurrent detection confirmation time) can be obtained and used as a limit value for the energization time. In this case, the energization time is monitored so as not to exceed the overcurrent detection confirmation time. Whichever method is used, both the semiconductor switch 110 and the power supply line 11 can be appropriately monitored and protected.

  According to the power supply device 100 of the present embodiment, even if an abnormality occurs in the control unit 120, the semiconductor switch 110 that controls power supply to a load having an important function can be maintained in an on state. Safety can be improved. As a result, the semiconductor switch can be applied to the power supply control of the load, which has been excluded from the application because of its high importance, and the applicable range of the semiconductor switch can be expanded.

(Second Embodiment)
A power supply apparatus according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing the configuration of the power supply apparatus 200 of this embodiment. The power supply apparatus 200 according to the present embodiment has a configuration in which the power supply apparatus 100 according to the first embodiment further includes an abnormality control unit 232.

  The abnormality control unit 232 inputs the reset signal 32 output from the monitoring unit 130 to the control unit 120 together with the protection characteristic adjustment unit 131 when the monitoring unit 130 detects an abnormality of the control unit 120. At the same time, the external signal 30 input to the control unit 120 is input. With this configuration, when the reset signal 32 is input from the monitoring unit 130, the abnormality control unit 232 can determine from the external signal 30 whether the target semiconductor switch 110 is requested to be turned on.

  When the abnormality control unit 232 determines that the target semiconductor switch 110 is requested to be turned on, the drive signal 31 is output to the semiconductor switch 110 instead of the control unit 120. Thereby, the semiconductor switch 110 can maintain the ON state in accordance with the drive signal 31 input from the abnormality control unit 232.

  The abnormal-time control unit 232 can be configured to output the drive signal 31 that maintains the previous ON state to the semiconductor switch 110, but is not limited thereto, and the control corresponding to the abnormality of the control unit 120 It is also possible to configure so that As an example, the drive signal 31 can be a pulse signal such as a PWM (Pulse Width Modulation) control signal. When the load 20 is, for example, a lamp, the lamp can be blinked by using the drive signal 31 as a pulse signal. By blinking the lamp, it is possible to notify the user of an abnormality in the power supply device 200.

  Further, when the drive signal 31 output from the abnormality control unit 232 is a pulse signal, the power consumption at the load 20 is reduced, so that power saving can be achieved. Furthermore, when the control unit 120 is abnormal, the threshold value for the overcurrent set in the self-protection means 111 of the semiconductor switch 110 is changed to a low value on the safe side, but the energizing current is changed using the drive signal 31 as a pulse signal. By lowering, it is possible to prevent the threshold value changed to a low value from being exceeded.

  As a method of intermittently outputting the drive signal 31 to generate a pulse signal, for example, a clock pulse when the monitoring unit 130 monitors the control unit 120 can be used. As described above, the monitoring unit 130 regularly receives a prescribed signal from the control unit 120, but generates a clock pulse for regular input. Therefore, the abnormal time control unit 232 can output the intermittent drive signal 31 to the semiconductor switch 110 by inputting the clock pulse from the monitoring unit 130. This eliminates the need for the abnormal time control unit 232 to generate a clock pulse by itself, and simplifies the configuration.

  According to the power supply device 200 of the present embodiment, in addition to being able to maintain power supply to the important load 20 when the control unit 120 is abnormal, as with the power supply device 100 of the first embodiment, The power supply can be saved, thereby preventing the overcurrent threshold from being exceeded.

(Third embodiment)
A power supply apparatus according to a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of the power supply apparatus 300 of this embodiment. In the power supply device 300 according to the present embodiment, a protection characteristic adjustment unit 331 is provided inside the semiconductor switch 310.

  In the power supply devices 100 and 200 according to the first and second embodiments, the protection characteristic adjustment unit 131 that detects an abnormality of the control unit 120 with the monitoring unit 130 and inputs the reset signal 32 from the monitoring unit 130 is the semiconductor switch 110. By outputting the adjustment signal 33, the semiconductor switch 110 can appropriately monitor both itself and the power supply line 11.

  On the other hand, the power supply apparatus 300 according to the present embodiment is configured such that an abnormality of the control unit 120 is detected by the semiconductor switch 310. Since the semiconductor switch 310 receives the drive signal 31 from the control unit 120, the abnormality of the control unit 120 can be detected by checking the drive signal 31. That is, in the semiconductor switch 310, it is determined whether the drive signal 31 has a specified value that is normal or within a normal range, and is not a normal specified value or is within a normal range. Therefore, it is possible to detect an abnormality in the control unit 120 when it is determined that the control unit 120 is not present.

  When the semiconductor switch 310 detects an abnormality of the control unit 120 as described above, the protection characteristic adjustment unit 331 provided therein changes the overcurrent threshold. As a result, it is possible to monitor so as to satisfy the overcurrent thresholds of both the semiconductor switch 310 and the power supply line 11. In this embodiment, since the process when the control unit 120 becomes abnormal can be performed only by the semiconductor switch 310, the configuration of the power supply apparatus 300 can be simplified.

  As still another embodiment of the power supply device of the present invention, the semiconductor switch periodically inputs a status notification signal from the control unit, and the status notification signal is not output from the control unit, or the signal value of the status notification signal When the switch becomes abnormal, the semiconductor switch can be made to determine whether or not the controller is abnormal.

  Even when the control unit 120 is normal, even when communication of control information is interrupted due to an abnormality in the communication unit 140 or the like, the overcurrent threshold value of the self-protecting means 111 is set, for example, as a preset value (safety By changing the mode setting value), it is possible to monitor the overcurrent more safely.

  In the above embodiment, the power supply side (high side) switch has been described as an example. However, the configuration is not limited as long as a plurality of switches need to be controlled by a small number of control units. The power supply device of the present invention can be applied. The description in this embodiment shows an example of the power supply apparatus according to the present invention, and the present invention is not limited to this. The detailed configuration and detailed operation of the power supply device in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Power supply 11 Electric power supply line 20 Load 100,200,300 Power supply apparatus 110,310 Semiconductor switch 111 Self-protection means 120 Control part 130 Monitoring part 131,331 Protection characteristic adjustment part 140 Communication part 232 Control part in abnormality

Claims (7)

A semiconductor switch provided in a power supply line for supplying power to a load from a power supply, and having self-protection means for turning on / off an energization current and monitoring overcurrent based on one or more overcurrent protection characteristics;
A control unit that controls one or more of the semiconductor switches and has monitoring / protecting means for monitoring and protecting the semiconductor switches and the power supply line;
A monitoring unit for monitoring the operation of the control unit;
A power supply apparatus comprising: a protection characteristic adjusting unit that adjusts a limit value for monitoring an overcurrent of the self-protecting means when an abnormality of the control unit is detected by the monitoring unit. The protection characteristic adjustment unit adjusts a limit value for monitoring the overcurrent, and sets a threshold for the overcurrent so as to satisfy both the overcurrent protection characteristic for the semiconductor switch and the wire smoke generation characteristic for the power supply line. The power supply device according to claim 1, wherein the power supply device is adjusted. The protection characteristic adjustment unit adjusts a limit value for monitoring the overcurrent, and energizes the semiconductor switch so as to satisfy both the overcurrent protection characteristic for the semiconductor switch and the wire smoke generation characteristic for the power supply line. The power supply device according to claim 1, wherein an energization allowable time for the current is adjusted. 4. The apparatus according to claim 1, further comprising an abnormality control unit that outputs a predetermined drive signal to the semiconductor switch when an abnormality of the control unit is detected by the monitoring unit. 5. Power supply device. The power supply apparatus according to claim 4, wherein the abnormality control unit outputs a pulse signal that repeatedly turns on and off at a predetermined cycle as the drive signal. The monitoring unit monitors the operation of the control unit using a predetermined clock pulse,
The power supply apparatus according to claim 5, wherein the abnormality control unit generates the pulse signal by inputting the clock pulse from the monitoring unit. The power supply device according to any one of claims 1 to 6, wherein the protection characteristic adjusting unit adjusts at least a threshold for a short-term overcurrent and a threshold for a long-term overcurrent.

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