JP2018121414A - Power Supply Abnormality Reporting System - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply abnormality reporting system capable of reporting an abnormal operation of a switching power supply circuit to a monitoring server even after detecting the abnormal operation.SOLUTION: Even if an abnormal operation of an active state of a switching transistor Tr1 is detected, an operation of a load device is made continuous by an output of a switching power supply circuit, and the abnormal operation of the switching transistor Tr1 is reported from the load device to the monitoring server via a computer network. Since the time required for reporting is short, there is no danger of fire occurrence even if the switching transistor Tr1 is operated in an active state.SELECTED DRAWING: Figure 2

Description

  In the present invention, when a switching transistor of a switching power supply circuit that converts a DC input voltage into a stable DC voltage suitable for a load device by switching operation of the switching transistor operates abnormally, the abnormal operation is transmitted to the monitoring server via the Internet. It relates to a power failure notification system to report.

  The switching power supply circuit is used as a power source for various electronic devices that operate with a DC voltage, as a DC-DC converter that converts a DC unstable input voltage into a stable DC output voltage and outputs it to a load device. Constant voltage and constant current are controlled so that the output voltage and output current are in accordance with the rating of the electronic device as the load device. However, if a failure occurs in a power supply line connected to the control circuit or the load device, an abnormally high output current flows through the output line, causing a fire.

  Conventionally, as a countermeasure, a thermal fuse is interposed in the output line, as shown in FIG. 5, for example, the output line is shut off 5 minutes after detecting a high temperature of about 50 ° C., or a current detection resistor is connected in series with the output line. When an abnormal current is detected from the voltage across the current detection resistor, the output line is cut off (Patent Document 1).

  On the other hand, the constant voltage and constant current control of the switching power supply circuit is performed by changing the on-duty of the drive circuit that controls opening and closing of the switching transistor, but the drive circuit fails for some reason and the switching transistor is always on-controlled. When the drive signal is output, the switching transistor operates in an active state, and as shown in FIG. 5, a relatively high output current flows over a long period of time, so that the temperature around the power supply line gradually rises for 6 hours. Later, the temperature rises to about 90 ° C. and then changes at this temperature.

  Load devices that operate using a switching power supply circuit as a direct current power supply include devices that are always supplied with power without being stopped, such as communication routers, surveillance cameras, traffic lights, and household capacitors. When a high current flows through the power supply line or power supply pattern, there are serious problems such as deterioration of parts used or a fire due to a short circuit between printed circuit board patterns due to low-temperature carbonization. However, since the output current that rises due to the operation in the active state is not a high output current that can be sensed by a temperature fuse or a current detection resistor, the above-described detection means cannot cope with it.

  Therefore, in the switching power supply circuit 100 described in Patent Document 2 shown in FIG. 6, when the switching transistor Tr1 operates abnormally in an active state, the switching transistor Tr1 does not open and close at a predetermined cycle, and the switching transistor Tr1 is connected to the inductor L1. Focusing on the fact that the voltage Vd at the connection point A on the side does not change, in the abnormality detection circuit 101 connected to the connection point A, when the voltage Vd at the connection point A does not change during a detection period longer than a predetermined period, The operation of the switching transistor Tr1 is determined.

  In addition, a switching transistor Tr2 serving as the protection circuit 102 is connected between the high-voltage power supply terminal 110a and the switching transistor Tr1, and the abnormality detection circuit 101 is connected to the gate of the switching transistor Tr2. The switching transistor Tr2 is normally controlled to be closed (ON control) by a drive signal output from the abnormality detection circuit 101. When the abnormality detection circuit 101 determines that the operation is in the active state of the switching transistor Tr1, the opening control (OFF control) is performed. The current supply from the DC input power supply 110 to the switching transistor Tr1 is stopped, thereby preventing abnormal heat generation of the switching transistor Tr1 and low-temperature carbonization of the printed wiring board on which the output line is wired.

Japanese Patent No. 3463134 Japanese Patent No. 5811237

  In the conventional switching power supply circuit 100 described above, when it is detected that the switching transistor Tr1 operates in an active state, a fail-safe that stops the current supply to the switching transistor Tr1 and stops the operation of the DC voltage converter 103 is provided. work. Therefore, even if an attempt is made to notify the outside that the switching transistor Tr1 is operating abnormally, the power supply to the reporting means is also interrupted, so that the user stops the power supply to the load device and stops the operation of the load device. In addition to this phenomenon, the abnormal operation of the switching power supply circuit 100 cannot be known.

  Further, when it is detected that the switching transistor Tr1 operates in an active state, the power supply from the switching power supply circuit 100 to the load device RL is immediately interrupted, and the operation of the load device is suddenly stopped. There was a problem that it was not possible to restore the previous normal operation state.

  In addition, a load device that operates using the output of the switching power supply circuit as a DC power source is used as an IoT (Internet of Thing) device, and a large number of IoT devices are connected to a monitoring server via the Internet. Although a monitoring system for centralized monitoring is known, even if an abnormal operation of the switching power supply circuit 100 is detected, if the operation of the IoT device receiving power supply from the switching power supply circuit stops, the abnormal operation is similarly performed. The monitoring server cannot report to the monitoring server, and the monitoring server cannot know the specific cause only by knowing that the operation of the IoT device has stopped.

  The present invention has been made in view of such conventional problems, and provides a power supply abnormality reporting system capable of reporting abnormal operation of a switching power supply circuit to a monitoring server even after detecting the abnormal operation. With the goal.

  It is another object of the present invention to provide a power supply abnormality reporting system that specifically reports a cause of abnormality in a switching power supply circuit that supplies DC power to an IoT device to a monitoring server.

In order to achieve the above-mentioned object, a power supply abnormality notification system according to claim 1 is connected in series to a DC input power supply, and a switching transistor that forms a closed circuit with the DC input power supply is controlled to open and close the switching transistor at a predetermined cycle. Drive circuit that outputs a drive signal to the control terminal of the switching transistor, a capacitor connected between the pair of high-voltage side output lines and the low-voltage side output line, and the current flowing from the DC input power supply by the switching transistor switching operation A switching power supply circuit having an inductor for converting an output voltage between the pair of high-voltage side output lines and the low-voltage side output lines into a DC voltage different from the input voltage of the DC input power supply;
A load device connected between a pair of high-voltage side output lines and low-voltage side output lines and operating the output of the switching power supply circuit as a DC power supply, and monitoring the switching operation of the switching transistor, and detecting the operation of the switching transistor in the active state An abnormality detection circuit that outputs abnormal operation information to the load device, and a monitoring server connected to the load device via a computer network. The load device outputs the abnormal operation information output from the abnormality detection circuit to the computer. It transmits to a monitoring server via a network, and reports the operation | movement in the active state of a switching transistor.

  While the switching transistor of the switching power supply circuit is operating in an active state, a relatively high output current is output to the load device from between the pair of high-voltage side output lines and the low-voltage side output lines. Therefore, the operation of the load device is maintained without stopping the output from the switching power supply circuit. Therefore, the load device transmits the abnormal operation information output from the abnormality detection circuit that detects the operation of the switching transistor in the active state to the monitoring server via the computer network, and the operation of the switching transistor in the active state to the monitoring server. Can be reported.

The power supply abnormality notification system according to claim 2, wherein the switching power supply circuit further includes an emergency stop switch connected between the DC input power supply and the switching transistor,
The monitoring server, after receiving abnormal operation information from the load device, outputs a control signal for controlling the opening of the emergency stop switch to the switching power supply circuit via the load device, and disconnects the connection between the DC input power supply and the switching transistor. It is characterized by.

  The monitoring server that has received the abnormal operation information outputs a control signal for controlling the opening of the emergency stop switch to the switching power supply circuit, and the current flowing from the DC input power supply to the switching transistor is stopped, so that the opening / closing operation of the switching transistor is stopped.

  The power failure notification system according to claim 3 is an emergency stop to the switching power supply circuit via the load device after the monitoring server receives the abnormal operation information from the load device and after a predetermined period specified by the load device has elapsed. A control signal for opening the switch is output.

  The load device receives abnormal operation information from the abnormality detection circuit, transfers the abnormal operation information to the monitoring circuit, and then opens the emergency stop switch from the monitoring server to the switching power supply circuit after the elapsed time specified by the load device. A control signal to be controlled is output, and supply of DC power from the switching power supply circuit to the load device is stopped.

The power supply abnormality notification system according to claim 4, wherein the switching power supply circuit is connected in series to the DC input power supply, and the first switching transistor that forms a closed circuit with the DC input power supply, and opens and closes the first switching transistor at a predetermined cycle. A first drive circuit that outputs a first drive signal to be controlled to a control terminal of the first switching transistor, a first capacitor connected between the pair of high-voltage side connection lines and the low-voltage side connection lines, and opening and closing of the first switching transistor A DC voltage having a first inductor that converts the output voltage between the pair of high-voltage side connection lines and the low-voltage side connection lines into a DC voltage different from the input voltage of the DC input power supply, with the current flowing from the DC input power supply interrupted by the operation. A conversion circuit section;
The second switching transistor connected between the DC input power supply and the first switching transistor, and the control terminal of the second switching transistor always outputs a second drive signal for closing and controlling the second switching transistor, and the protection operation mode. The second drive circuit for outputting a second drive signal for controlling the opening and closing of the second switching transistor at a predetermined cycle, and a pair of high-voltage side connection lines and low-voltage side connection lines on the input side of the DC voltage conversion circuit section. In the protection operation mode, the current flowing from the DC input power supply is intermittent due to the opening / closing operation of the second switching transistor, and the DC voltage obtained by stepping down the voltage across the second capacitor is the input voltage of the DC input power supply. And a protection circuit having a second inductor that converts to
The abnormality detection circuit monitors the opening / closing operation of the first switching transistor, and outputs abnormal operation information to the load device when detecting the operation of the first switching transistor in the active state.
The monitoring server, after receiving abnormal operation information from the load device, outputs a control signal for operating the protection circuit in the protection operation mode to the switching power supply circuit via the load device.

  When the first switching transistor of the DC voltage conversion circuit unit operates in an active state and the abnormal operation information is output from the load device to the monitoring server, the monitoring server provides a protection circuit to the switching power supply circuit via the load device. A control signal for operating in the protection operation mode is output. As a result, the switching power supply circuit in which the protection circuit operates in the protection operation mode converts the input voltage of the DC input power supply to a stable different DC voltage and outputs it to the load device even if the DC voltage conversion circuit section is operating abnormally. Thus, the load device operates continuously without stopping.

  Since the voltage on the high voltage side of the first switching transistor operating in the active state is approximately equal to the voltage across the second capacitor obtained by stepping down the input voltage of the DC input power supply, the voltage applied to the first switching transistor is protected. There is no danger of abnormal heat generation even when the circuit is switched to the protective operation mode and the first switching transistor operates in an active state.

  The power supply abnormality notification system according to claim 5 is characterized in that the switching power supply circuit and the abnormality detection circuit are built in the load device.

  An abnormal operation of the switching power supply circuit built in the load device can be reported to the monitoring server.

  The power failure notification system according to claim 6 is characterized in that the computer network is the Internet and the load device is an IoT device connected to the Internet.

  A large number of IoT (Internet of Things) devices are connected to the Internet, and an abnormal operation of a switching power supply circuit serving as a DC power source of the large number of IoT devices can be monitored from a monitoring server.

  According to the invention of claim 1, since the operation of the switching power supply circuit is not stopped even after the abnormality detection circuit detects the operation of the switching transistor in the active state, the load device reports the abnormal operation of the switching transistor to the monitoring server. can do. As a result, it is possible to notify the user of the danger of heat generation due to the output of a high output current to the load device, and to take measures to avoid fire accidents before the occurrence of a fire, such as stopping the operation of the switching power supply circuit.

  Further, the monitoring server may indicate that the cause of the abnormal operation of the load device that has transmitted the abnormal operation information is the active operation of the switching transistor of the switching power supply circuit that supplies DC power to the load device from the received abnormal operation information. You can know specifically.

  According to the second aspect of the present invention, the monitoring server remotely controls the protective operation for stopping the abnormal operation of the switching power supply circuit, and the circuit component is damaged or fires due to abnormal heat generation of the switching transistor operating in the active state or high output current. Can be prevented in advance.

  According to the invention of claim 3, the load device is specified by the load device until the supply of DC power from the switching power supply circuit to the load device is stopped after the abnormal operation information is input from the abnormality detection circuit. Therefore, the operation can be safely stopped after the load device is provided with a measure capable of recovering to the operation state before the stop.

  In the active operation of the switching transistor, since a high abnormal current that causes a fire immediately is not output, after the elapsed time specified by the load device after the abnormality detection circuit detects the operation, There is no danger of fire even if the operation of the switching power supply circuit is stopped.

  According to the invention of claim 4, even if the DC voltage conversion circuit portion of the switching power supply circuit operates abnormally, the output of the DC power supply is maintained to the load device by operating the protection circuit in the protection operation mode with the fault tolerant design. Therefore, abnormal operation information can be reported from the load device to the monitoring server while the operation of the load device is continued.

  Further, even if the first switching transistor of the DC voltage conversion circuit unit is operated in an active state, there is no danger of abnormal heat generation of the first switching transistor.

  According to the invention of claim 5, in the monitoring server, the cause of the abnormal operation is the operation in the active state of the switching transistor of the switching power supply circuit built in the load device based on the abnormal operation information transmitted from the load device. Can know.

  According to the sixth aspect of the present invention, when the operation state of a large number of load devices is centrally managed by a monitoring device connected via the Internet, the abnormal operation of the switching power supply circuit serving as the DC power source of each load device and its cause are described. Can report to monitoring server.

1 is a block diagram of a power supply abnormality notification system 1 according to a first embodiment of the present invention. 1 is a circuit diagram of a main part of a power supply abnormality reporting system 1. FIG. It is a principal part circuit diagram of the power supply abnormality notification system 20 which concerns on 2nd Embodiment. 3 is a circuit diagram of an abnormality detection / protection control unit 6. FIG. It is a graph which shows the relationship between the temperature change by the elapsed time of abnormal operation when the switching power supply circuit is performing abnormal operation, and the output current output by abnormal operation. 1 is a circuit diagram of a conventional switching power supply circuit 100. FIG.

  The power supply abnormality notification system 1 according to the first embodiment of the present invention includes a monitoring server 11 that connects the abnormal operation of the switching power supply circuit 3 that converts a 12V DC input voltage Vi to a 5V DC output voltage Vo via the Internet. Hereinafter, the power supply abnormality notification system 1 will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a block diagram of the power supply abnormality reporting system 1 as a whole. The power supply abnormality reporting system 1 includes a switching power supply circuit 3 connected to a commercial AC power supply line via a rectifying and smoothing circuit 4 and an output of the switching power supply circuit 2. A load device that operates as a DC power source, and is connected between the IoT device 10 connected to the Internet, the switching power supply circuit 3 and the IoT device 10, and detects an abnormal operation of the switching power supply circuit 3; And a monitoring server 11 that monitors the operation of each of the plurality of IoT devices 10 via the Internet.

  The rectifying and smoothing circuit 4 connected between the commercial AC power supply line and the switching power supply circuit 3 rectifies and smoothes the commercial AC voltage using a diode bridge circuit and a smoothing capacitor, and the voltage fluctuates by about 10%. It is converted into a stable 12V DC voltage and output to the switching power supply circuit 3. Therefore, the DC input voltage Vi of the switching power supply circuit 3 is an unstable DC voltage of 12V, the high voltage side power supply terminal 30a of the DC input power supply 30 is + 12V, and the low voltage side power supply terminal 30b is grounded to a potential of 0V. It has become.

  The switching power supply circuit 3 steps down the DC input voltage Vi and outputs it between the high voltage side output terminal 32a connected to the IoT device 10 and the low voltage side output terminal 33a, the abnormality detection circuit 5, and the emergency stop. A switch 7 is provided. Between the high-voltage side power supply terminal 30a and the low-voltage side power supply terminal 30b of the DC input power supply 30, as shown in FIG. 2, there are a diode D1, a switching transistor Tr1, and a switching transistor Tr2 having a forward direction from the low voltage side to the high voltage side. They are connected in series, thereby forming a closed circuit.

  The connection point A between the diode D1 and the switching transistor Tr1 is connected to the high-voltage side connection line 32 whose other side is the high-voltage side output terminal 32a via the inductor L1, and the other side (anode) of the diode D1 with respect to the connection point A. Side) is connected to a low voltage side connection line 33 wired between the low voltage side power supply terminal 30b and the low voltage side output terminal 33a. Between the high-voltage side connection line 32 and the low-voltage side connection line 33, DC power of a stable output current Io and output voltage Vo is supplied to the IoT device 10 connected between the high-voltage side output terminal 32a and the low-voltage side output terminal 33a. Therefore, the capacitor C1 is connected.

  The switching transistor Tr1 is composed of an FET (field effect transistor) and is controlled to be opened and closed by a drive signal output from the constant voltage control circuit 40 to the gate of the switching transistor Tr1. Assuming that the switching transistor Tr2 serving as the emergency stop switch 7 is normally closed and controlled (ON control), the switching transistor Tr1 is closed and controlled (ON control), and while operating in a saturated state, the DC input power supply 30 A current flows from the inductor L1 to the inductor L1 to charge the capacitor C1, but the charging voltage of the capacitor C1, which becomes the output voltage Vo, becomes lower than the input voltage Vi by self-induction of the inductor L1. In addition, while the switching transistor Tr1 is controlled to open (off control) and operates in the cut-off state, the electric energy accumulated in the inductor L1 becomes a charging current that circulates through the diode D1, and charges the capacitor C1. The charging voltage of the capacitor C1 that is the output voltage Vo is maintained.

  Since the output voltage Vo can be controlled by the closing control time of the switching transistor Tr1 during the unit time, the constant voltage control circuit 40 negatively feeds back the on-duty of the drive signal for closing and controlling the switching transistor Tr1 from the output voltage Vo. Then, constant voltage control is performed so that the output voltage Vo becomes the operating voltage of the IoT device 10. For this reason, the constant voltage control circuit 40 has a pair of voltage dividing resistors R1 and R2 connected between the high voltage side connection line 32 and the low voltage side connection line 33, and the voltage at the connection point of the voltage dividing resistors R1 and R2. The reference power supply voltage Vref adjusted to a predetermined potential based on the operating voltage of the IoT device 10 is compared by the error amplifier 41 and output to the pulse width modulation circuit PWM. The pulse width modulation circuit PWM performs pulse width modulation on the transmission signal of a fixed period output from the oscillator OSC with the comparison signal of the error amplifier 41 and outputs the modulated signal to the drive circuit 42. The drive circuit 42 compares the comparison signal of the error amplifier 41. The drive signal whose on-duty is adjusted according to the output is output to the gate of the switching transistor Tr1.

  Thereby, for example, when the output voltage Vo is higher than the operating voltage of the IoT device 10, a drive signal with a reduced on-duty is output from the drive circuit 42 to the gate of the switching transistor Tr1, and the on-control time within a unit time Is shortened, the output voltage Vo decreases. Conversely, when the output voltage Vo is lower than the operating voltage of the IoT device 10, a drive signal with an increased on-duty is output to the gate of the switching transistor Tr1, and the on-control time within a unit time is extended. Since the output voltage Vo rises, the output voltage Vo is controlled at a constant voltage to a predetermined operating voltage that differs for each IoT device 10.

  On the other hand, the pulse width modulation circuit PWM or the like of the constant voltage control circuit 40 fails due to a lightning strike or the like, and a drive signal having a constant potential that activates the switching transistor Tr1 is supplied from the drive circuit 42 to the gate (base) of the switching transistor Tr1. If the output continues, the switching power supply circuit 3 keeps the switching transistor Tr1 in a normally closed state (on state), consumes input power by the on resistance of the switching transistor Tr1, and outputs an output voltage lower than the input voltage (dropper) Circuit).

  As described above, the operation of the switching transistor Tr1 in the active state has no danger that the output current Io suddenly rises to cause a fire, but if left untreated, the output current Io is relatively high for a long time. Since there is a danger that the printed circuit board continuously flows, the printed circuit board is carbonized at a low temperature, the pattern is short-circuited, and a fire is generated, in this embodiment, the operation in the active state of the switching transistor Tr1 is regarded as an abnormal operation. Detected by the abnormality detection circuit 5 connected to A and notifies the monitoring server 11.

  The method for detecting the abnormal operation of the switching transistor Tr1 by the abnormality detection circuit 5 is that the switching transistor Tr1 does not open and close at a predetermined cycle while the switching transistor Tr1 operates in an active state, and the switching transistor Tr1 and the inductor L1 of the switching transistor Tr1. Note that the voltage Vd at the connection point A on the connection side does not change. The abnormality detection circuit 5 activates the switching transistor Tr1 when the voltage Vd at the connection point A does not change during a detection period longer than a predetermined period. Detect as a state action.

  When the abnormality detection circuit 5 is connected to the IoT device 10 through a signal line 13 different from the power line that supplies DC power to the IoT device 10 and detects the active operation of the switching transistor Tr1, the switching transistor Tr1 operates in the active state. Is output to the IoT device 10 via the signal line 13.

  The abnormality detection circuit 5 is connected to the gate of the switching transistor Tr2 that acts as an emergency stop switch. When an open control signal (to be described later) is input from the IoT device 10 via the signal line 13, the abnormality detection circuit 5 is connected to the gate of the switching transistor Tr2. A drive signal for controlling the opening of the switching transistor Tr2 is output. As a result, the current supply from the DC input power supply 30 to the switching transistor Tr1 is stopped, and the operation of the switching transistor Tr1 operating in the active state is stopped. As a result, the output from the switching power supply circuit 3 is also stopped, and the risk of fire due to the active operation of the switching transistor Tr1 disappears.

  The IoT device 10 that operates by receiving a DC power supply from the switching power supply circuit 3 can be connected to the Internet. Various devices such as a surveillance camera, a lighting device, a home appliance, a personal computer, or a router connected to these devices can be used. In order to connect to the Internet using the TCP / IP protocol, an IP address is assigned to each IoT device 10. In the present embodiment, as shown in FIG. 1, the IoT device 10a that operates with the DC power supply of the first switching power supply circuit 3a is a personal computer, and two IoT devices that operate with the DC power supply of the second switching power supply circuit 3b. The devices 10b and 10c are a lighting fixture and a surveillance camera, respectively.

  Each IoT device 10a, 10b, 10c is connected to the Internet through a router and a line terminator (not shown), and similarly connected to the monitoring server 11 connected to the Internet in a state where bidirectional communication is always possible. ing. As a result, each IoT device 10a, 10b, 10c periodically adds its imaging information to the monitoring server 11 and transmits it to the monitoring server 11, and the monitoring server transmits each IoT from the transmission information. The operating state of the device 10 is monitored.

  Of the three IoT devices 10a, 10b, and 10c, the IoT devices 10a and 10c connected to the abnormality detection circuit 5 through the signal line 13 are necessary when the abnormal operation information is input from the abnormality detection circuit 5, respectively. In addition, the abnormal operation information input is transmitted to the monitoring server 11, and the abnormal operation of the switching power supply circuit 3 in which the switching transistor Tr1 is operating is reported to the monitoring server 11.

  In addition, each IoT device 10 that reports abnormal operation information is transmitted with abnormal operation information when the monitoring server 11 described later permits the output of a control signal for controlling the opening of an emergency stop switch and the output of the control signal. Then, control setting information that defines a predetermined elapsed time from when the control signal is output is set for each IoT device 10, and the control setting information is included in the abnormal operation information and transmitted to the monitoring server 11. The control signal for controlling the opening of the emergency stop switch is to stop the operation of the switching power supply circuit 3 that supplies DC power to the IoT device 10, so that the control setting information is set according to the operation content of the IoT device 10, for example Even if the switching transistor Tr1 is operating in an active state, for a device such as the lighting fixture 10b that needs to continue operation, control setting information that does not permit output of a control signal is predetermined before the operation is stopped. For devices such as the personal computer 10a that require the end process, control setting information that permits the output of a control signal that defines a predetermined elapsed time required for the end process is set.

  When the monitoring server 11 receives the abnormal operation information from the IoT device 10, the monitoring server 11 notifies the user of the abnormal operation of the switching power supply circuit 3 serving as a DC power source of the IoT device 10 using an attached display or speaker.

  Further, when the control setting information included in the abnormal operation information is control setting information that permits output of a control signal that defines a predetermined elapsed time, the predetermined operation is received after receiving the abnormal operation information from the IoT device 10. After the elapse of time, a control signal for opening control of the emergency stop switch is transmitted from the monitoring server 11 to the IoT device 10.

  The IoT device 10 that has received this control signal from the monitoring server 11 outputs a control signal to the abnormality detection circuit 5 connected via the signal line 13, and opens the emergency stop switch 7 of the switching power supply circuit 3 from the abnormality detection circuit 5. A control signal to be controlled is output. As a result, the operation of the switching power supply circuit 3 is stopped, and the supply of DC power to the IoT device 10 is also stopped. However, since the IoT device 10 receives the abnormal operation information from the abnormality detection circuit 5 and stops supplying the DC power from the switching power supply circuit 3 after a predetermined elapsed time set for the IoT device 10, The operation of the IoT device 10 can be safely stopped in a state where it can be returned to the normal operation state.

  The power supply abnormality notification system 20 according to the second embodiment includes a switching power supply circuit 21 having a fault tolerant function for maintaining the same output as that in a normal operation state even when the switching transistor Tr1 operates in an active state. The power supply abnormality notification system 20 will be described with reference to FIGS. 3 and 4. As apparent from comparison with the power supply abnormality notification system 1 shown in FIG. 2, the power supply abnormality notification system 20 adds a protection circuit 22 to the switching power supply circuit 21 without changing the basic configuration of the switching power supply circuit 3, and The abnormality detection circuit 15 is built in the abnormality detection / protection control unit 6 of the protection circuit 22. Accordingly, since the main configuration is common to the above-described power supply abnormality notification system 1, the same reference numerals are given to configurations that operate substantially the same or similar, and detailed description thereof is omitted.

  Switching transistor Tr2 that forms part of the protection circuit 22 and switching that forms part of the DC voltage converter 12 between the + 12V high-voltage side power supply terminal 30a and the 0V low-voltage side power supply terminal 30b of the DC input power supply 30. The transistor Tr1 and the diode D1 whose forward direction is from the low voltage side to the high voltage side are connected in series to form a closed circuit.

  As shown in FIG. 3, the protection circuit 22 is formed on the DC input power supply 30 side, which is the input side of the DC voltage conversion unit 12, and includes circuit elements that operate in the same manner as each circuit element of the DC voltage conversion unit 12. ing. That is, between the high voltage side power supply terminal 30a and the low voltage side power supply terminal 30b, the DC input power supply 30 side of the closed circuit formed by the switching transistor Tr1 and the diode D1 is connected to the high voltage side power supply terminal 30a and the low voltage side power supply terminal 30b. Thus, a closed circuit is formed in which the switching transistor Tr2 and a diode D2 having a forward direction from the low voltage side to the high voltage side are connected in series.

  An inductor L2 is connected between a connection point between the switching transistor Tr2 and the diode D2 and an input side (source) of the switching transistor Tr1, a connection point B2 between the inductor L2 and the switching transistor Tr1, and a low-voltage side connection line. A capacitor C2 that connects the input side of the switching transistor Tr1 to a stable DC voltage while the protection circuit 22 operates in a protection operation mode to be described later is connected between the capacitors 33.

  While the protection circuit 22 is operating in a normal operation mode, which will be described later, the switching transistor Tr2 is always on-controlled, and if the voltage drop between the switching transistor Tr2 and the inductor L2 through which a direct current flows is ignored, The DC input voltage Vi is applied, and the DC voltage conversion unit 12 steps down the input voltage Vi in the same manner as the switching power supply circuit 3 and supplies the DC power of the output voltage Vo subjected to constant voltage control to the IoT device 10.

  The switching transistor Tr2 is a P-channel FET (field effect transistor), and has a gate connected to an output of a drive circuit 25 (to be described later) of the protection circuit 22 and is normally on-controlled by a drive signal output from the drive circuit 25. When the active operation of the switching transistor Tr1 is detected, the on / off control is performed by the drive signal.

  As shown in FIG. 4, the abnormality detection / protection control unit 22 includes a constant voltage control circuit 14 that operates when the protection circuit 22 operates in a protection operation mode, which will be described later, and a switching transistor Tr1 and an inductor L1. In order to monitor the potential at the connection point A, an abnormality detection circuit 15 having a detection terminal SW connected to the connection point A and an RS flip-flop circuit 16 connected to the output of the abnormality detection circuit 15 are provided.

  The constant voltage control circuit 14 connects an offset power source 24 that outputs a DC offset voltage corresponding to the target differential voltage Vtrset that is controlled at a constant voltage in the protection operation mode, an inverting input terminal to the SET terminal, and a non-inverting input terminal as an offset power source. An error amplifier 23 connected to the SENCE terminal via 24, and a pulse width modulation circuit PWM2 that performs pulse width modulation on the output of the error amplifier 23 such as a triangular wave or sawtooth wave having a fixed frequency of 1 MHz output from the oscillator OSC2. And a drive circuit 25 that outputs the modulated signal output from the pulse width modulation circuit PWM2 in the protection operation mode to the gate of the switching transistor Tr2 as a drive signal.

  The SET terminal to which the inverting input terminal of the error amplifier 23 is connected is connected to the connection point B2 between the inductor L2 and the switching transistor Tr1 of the high-voltage side connection line 32, and the SENCE terminal to which the non-inverting input terminal is connected via the offset power supply 24. Is connected to the connection point C of the high-voltage side connection line 32 connected to the IoT device 10, and accordingly, the error amplifier 23 has a voltage obtained by adding the DC offset voltage Voff to the output voltage Vo and a voltage on the high-voltage side of the switching transistor Tr1. And compare. While the protection circuit 22 is operating in the protection operation mode, a DC output current flows through the inductor L1, and if the voltage drop at the inductor L1 is ignored, the error amplifier 23 is connected to the high voltage side and the low voltage side of the switching transistor Tr1. The difference voltage difference voltage Vtr is compared with the target difference voltage Vtrset defined by the DC offset voltage Voff, and the voltage across the switching transistor Tr1 is constant-voltage controlled to the target difference voltage Vtrset.

  As a result, even if the switching transistor Tr1 continues to operate in an active state, the voltage applied to both ends of the on-resistance r of the switching transistor Tr1 is constant-voltage controlled to a predetermined target differential voltage Vtrset, and the DC input voltage Vi and the output voltage Vo Regardless of the voltage, the switching transistor Tr1 does not generate abnormal heat.

  The abnormality detection circuit 15 and the RS flip-flop circuit 16 are connected between the constant current circuit 17 connected to the high voltage side power supply terminal 30a and the low voltage side power supply terminal 30b, and are converted into a stable potential by the constant current circuit 17. 30 is operating as a power source.

  The abnormality detection circuit 15 includes a comparison circuit (not shown) that compares the voltage Vd at the connection point A with a threshold voltage Vth that is arbitrarily set within the fluctuation range of the voltage Vd during the switching operation of the switching transistor Tr1. While the transistor Tr1 is normally switching, the polarity of the comparison circuit is inverted within a fixed period T of at least 1 μsec. On the other hand, when the pulse width modulation circuit PWM1 or the like fails for some reason and the drive signal output to the gate of the switching transistor Tr1 becomes a constant potential, the switching transistor Tr1 operates in an active state, and the DC input voltage Vi is a substantially constant potential. Therefore, the voltage Vd at the connection point A is also a constant potential, and the polarity of the output of the comparison circuit is not inverted within the fixed period T. Therefore, the abnormality detection circuit 15 determines that the operation is abnormal in the active state when the polarity of the output of the comparison circuit is never reversed during the detection period set to 2 μsec longer than the fixed period T of the drive circuit 42. Outputs the “L” level output to the “H” level and outputs it to the set input of the RS flip-flop circuit 16.

  After the “L” level reset signal is input, the RS flip-flop circuit 16 outputs the “L” level output signal until the “H” level set signal from the abnormality detection circuit 15 is input. On the other hand, when the “H” level set signal determined to be the active operation of the switching transistor Tr1 is input from the abnormality detection circuit 15, the “H” level is input until the next “L” level reset signal is input. The output signal is output.

  The protection circuit 22 operates in the normal operation mode while the output signal of “L” level for determining the normal operation of the switching transistor Tr1 is being output from the RS flip-flop circuit 16, and the drive circuit 25 is connected to the switching transistor Tr2. A + 0V drive signal for continuously controlling the switching transistor Tr2 is output to the gate. Further, when an “H” level output signal indicating that the operation of the switching transistor Tr1 in the active state is detected is output from the RS flip-flop circuit 16, the protection circuit 22 operates in the protection operation mode, and the drive circuit 25 outputs a drive signal for controlling on / off of the switching transistor Tr2 to the gate of the switching transistor Tr2 based on the modulated signal output from the pulse width modulation circuit PWM2.

  When the protection circuit 22 shifts to the protection operation mode, the switching transistor Tr2 is on / off controlled by a drive signal output from the drive circuit 25. While the switching transistor Tr2 is ON-controlled, a current flows from the DC input power supply 30 to the inductor L2 and charges the capacitor C2. The charging voltage of the capacitor C2, which is a DC voltage on the high voltage side of the switching transistor Tr1, The input voltage Vi is lowered by the self-induction of L2. Further, while the switching transistor Tr2 is controlled to be turned off and operates in the cut-off state, the electric energy accumulated in the inductor L2 becomes a charging current that circulates through the diode D2, charges the capacitor C2, and the switching transistor Tr1 The charging voltage of the capacitor C2, which is a high-voltage side DC voltage, is maintained.

While the switching transistor Tr1 is operating in an active state, the amount of heat generated by the switching transistor Tr1 is r, the on-resistance is r, the source voltage on the connection point B2 side (charge voltage of the capacitor C2), and the drain on the connection point A side. If the voltage difference between the voltages (output voltage Vo) is Vtr, it is expressed by (Vtr) ² / r. Here, while the protection circuit 22 is operating in the protection operation mode as described above, the voltage of the source on the connection point B2 side of the switching transistor Tr1 is lowered to a voltage sufficiently lower than the input voltage Vi, Since the difference voltage Vtr from the output voltage Vo of the drain on the connection point A side is lowered, the amount of heat generation is drastically reduced and the risk of abnormal heat generation is eliminated.

  Further, the output of the above-described RS flip-flop circuit 16 is connected to the IoT 10 as a load device via the signal line 13 in addition to the drive circuit 25. Therefore, when the abnormality detection circuit 15 detects the active operation of the switching transistor Tr1, an “H” level output signal representing the abnormal operation information is output to the IoT 10.

  The IoT device 10 connected to the output of the RS flip-flop circuit 16 monitors the input abnormal operation information when an “H” level output signal representing the abnormal operation information is input from the abnormality detection / protection control unit 6. When the monitoring server 11 receives the abnormal operation information from the IoT device 10 when the monitoring server 11 notifies the monitoring server 11 of the abnormal operation of the switching power supply circuit 21 operating in the active state of the switching transistor Tr1. Using a display or a speaker, the abnormal operation of the switching power supply circuit 21 serving as the DC power supply of the IoT device 10 is notified to the user.

  As a result, the fact that the switching transistor Tr1 is operating in an active state is communicated to the user by display or the like on the display device, and after the operation of the switching power supply circuit 21 is safely stopped, the faulty part is repaired and restored. Can do.

  It should be noted that when the cause of the failure that causes the switching transistor Tr1 to become active for some reason is solved while the protection circuit 22 is operating in the protection operation mode, and the switching transistor Tr1 resumes the switching operation, the abnormality detection circuit 15 determines that the operation is normal and outputs an “L” level reset signal to the RS flip-flop circuit 16, so that the protection circuit 22 returns to the normal operation mode in which the switching transistor Tr 2 is always turned on, and the DC voltage conversion unit 12 returns to normal operation.

  At the same time, since an output signal of “L” level indicating the normal operation of the switching transistor Tr1 is transmitted from the flip-flop circuit 16 to the monitoring server 11 via the IoT device 10, the switching power supply circuit 21 is operated normally from the monitoring server 11. The return is communicated to the user.

  In each of the above-described embodiments, the load device (IoT device) 10 and the monitoring server 11 are described as being connected via the Internet. However, if the load device (IoT device) 10 and the monitoring server 11 are connected via a computer network, a network such as a LAN or VAN, or each other There may be a plurality of networks to be connected.

  Further, it is not necessary to output abnormal operation information from all of the plurality of load devices 10 connected to the monitoring server 11 via the computer network, and the load device 10 to which no abnormal operation information is input from the switching power supply circuit like the IoT device 10b. May be connected to a computer network.

  Further, the switching power supply circuit and / or the abnormality detection circuit may be incorporated in the load device.

  In the above-described embodiment, the switching transistor Tr1 is operated in an active state due to an abnormality in the drive signal. However, the switching transistor Tr1 is caused by other causes such as a failure of the switching transistor Tr1 itself or an abnormal connection between circuit elements. It can also be applied when the device operates in an active state.

  The present invention is suitable for a system in which a monitoring server monitors the operation of a load device using a switching power supply circuit as a DC power supply via a computer network.

DESCRIPTION OF SYMBOLS 1 Power supply abnormality notification system 3 Switching power supply circuit 5 Abnormality detection circuit 6 Abnormality detection / protection control part 7 Emergency stop switch 10 Load device (IoT device)
DESCRIPTION OF SYMBOLS 11 Monitoring server 12 DC voltage conversion part 15 Abnormality detection circuit 20 Power supply abnormality notification system 21 which concerns on 2nd Embodiment Switching power supply circuit 22 Protection circuit

Claims (6)

A switching transistor connected in series to the DC input power supply and forming a closed circuit with the DC input power supply;
A drive circuit for outputting a drive signal for controlling opening and closing of the switching transistor at a predetermined cycle to a control terminal of the switching transistor;
A capacitor connected between the pair of high-voltage side output lines and the low-voltage side output lines;
The current flowing from the DC input power supply is intermittent by switching operation of the switching transistor, and has an inductor for converting the output voltage between the pair of high voltage side output lines and the low voltage side output lines into a DC voltage different from the input voltage of the DC input power supply. A switching power supply circuit;
A load device connected between the pair of high-voltage side output lines and the low-voltage side output lines and operating the output of the switching power supply circuit as a DC power supply;
An abnormality detection circuit that monitors the opening / closing operation of the switching transistor and outputs abnormal operation information to the load device when detecting the operation of the switching transistor in an active state;
A load server and a monitoring server connected via a computer network,
A load device transmits abnormal operation information output from an abnormality detection circuit to a monitoring server via a computer network, and reports an operation in an active state of a switching transistor. The switching power supply circuit further includes an emergency stop switch connected between the DC input power supply and the switching transistor,
The monitoring server, after receiving abnormal operation information from the load device, outputs a control signal for controlling the opening of the emergency stop switch to the switching power supply circuit via the load device, and disconnects the connection between the DC input power supply and the switching transistor. The power supply abnormality notification system according to claim 1. After receiving abnormal operation information from the load device, the monitoring server outputs a control signal for opening the emergency stop switch to the switching power supply circuit via the load device after elapse of a predetermined period specified by the load device. The power supply abnormality notification system according to claim 2, wherein Switching power supply circuit
A first switching transistor connected in series to the DC input power source and forming a closed circuit with the DC input power source;
A first drive circuit for outputting a first drive signal for controlling opening and closing of the first switching transistor at a predetermined cycle to a control terminal of the first switching transistor;
A first capacitor connected between the pair of high-voltage side connection lines and the low-voltage side connection lines;
A current flowing from the DC input power supply is interrupted by the opening / closing operation of the first switching transistor, and the output voltage between the pair of high-voltage side connection lines and the low-voltage side connection lines is converted to a different DC voltage from the input voltage of the DC input power supply. A DC voltage conversion circuit unit having an inductor;
A second switching transistor connected between the DC input power source and the first switching transistor;
To the control terminal of the second switching transistor, a second drive signal for normally closing and controlling the second switching transistor is output, and a second drive signal for controlling the opening and closing of the second switching transistor in a predetermined cycle is output in the protection operation mode. A second drive circuit that
A second capacitor connected between a pair of high-voltage side connection lines and low-voltage side connection lines on the input side of the DC voltage conversion circuit unit;
In the protection operation mode, the current flowing from the DC input power supply is intermittently generated by the opening / closing operation of the second switching transistor, and the second inductor that converts the voltage across the second capacitor into a DC voltage obtained by stepping down the input voltage of the DC input power supply. And a protection circuit having
The abnormality detection circuit monitors the opening / closing operation of the first switching transistor, and outputs abnormal operation information to the load device when detecting the operation of the first switching transistor in the active state.
The monitoring server outputs a control signal for operating the protection circuit in the protection operation mode to the switching power supply circuit via the load device after receiving the abnormal operation information from the load device. Power failure notification system. The power supply abnormality notification system according to any one of claims 1 to 4, wherein the switching power supply circuit and the abnormality detection circuit are built in a load device. 6. The power failure notification system according to claim 1, wherein the computer network is the Internet, and the load device is an IoT device connected to the Internet.

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