CN217981620U

CN217981620U - Surge current testing device

Info

Publication number: CN217981620U
Application number: CN202222242675.XU
Authority: CN
Inventors: 李秀全; 孔繁博; 关彬
Original assignee: Ziguang Computer Technology Co Ltd
Current assignee: Ziguang Computer Technology Co Ltd
Priority date: 2022-08-24
Filing date: 2022-08-24
Publication date: 2022-12-06
Anticipated expiration: 2032-08-24

Abstract

The utility model discloses a surge current testing arrangement, the device includes: the charging circuit comprises a rectifying circuit, a charging circuit, a control circuit, a first switch and a second switch; the rectifying circuit is connected with the alternating current power supply through a first switch and is connected with the charging circuit; the charging circuit is connected with an external load through a second switch; the control circuit is connected with the charging circuit and is respectively connected with the first switch and the second switch; when the first switch is closed and the second switch is opened, the alternating current power supply outputs direct current through the rectifying circuit so as to charge the charging circuit, and when the charging circuit is fully charged, the control circuit responds to a full-charge signal fed back by the charging circuit, opens the first switch and closes the second switch so as to discharge the charging circuit and provide surge current for an external load. The device provided by the utility model, realized using the function that the small capacity exchanges adjustable power and produces great surge current.

Description

Surge current testing device

Technical Field

The utility model relates to a surge current test technical field, concretely relates to surge current testing arrangement.

Background

At present, products such as a switching power supply of a computer and the like need surge current testing on an interface before leaving a factory, a commonly used testing instrument is an alternating current adjustable power supply, but the instrument has maximum current limitation, the current limit of a 3KVA alternating current adjustable power supply can only reach 30-40A generally, but the instantaneous surge current needed to be tested by a common switching power supply product can reach 200A at most, if the alternating current adjustable power supply with small capacity outputs such large testing current, an alternating current adjustable power supply overcurrent alarm or current limiting state can occur, if the surge current of the product is correctly tested, the capacity of at least 30KVA needs to be selected by the used alternating current adjustable power supply, but the alternating current adjustable power supply has large size and high cost, and brings troubles to the testing. If the 30KVA AC adjustable power supply is purchased just for testing the surge current, a large cost burden is brought to enterprises, and the use is inconvenient due to the large size.

SUMMERY OF THE UTILITY MODEL

Therefore, the to-be-solved technical problem of the utility model lies in using the adjustable power supply of low capacity alternating current to produce great surge current, and then provides a surge current testing arrangement.

In order to solve the above problem, the utility model provides a technical scheme as follows:

an embodiment of the utility model provides a surge current testing arrangement, the device includes: the charging circuit comprises a rectifying circuit, a charging circuit, a control circuit, a first switch and a second switch; the rectifying circuit is connected with an alternating current power supply through a first switch, and the rectifying circuit is connected with the charging circuit; the charging circuit is connected with an external load through a second switch; the control circuit is connected with the charging circuit and is respectively connected with the first switch and the second switch; when the first switch is closed and the second switch is opened, the alternating current power supply outputs direct current through the rectifying circuit so as to charge the charging circuit, and when the charging circuit is fully charged, the control circuit responds to a full electric signal fed back by the charging circuit, opens the first switch and closes the second switch so as to discharge the charging circuit and provide surge current for the external load.

Optionally, the rectifier circuit comprises: the device comprises an alternating current interface, a voltage detection interface, a protection resistor, an electromagnetic interference filter circuit and a rectifier bridge; the alternating current interface is connected with the alternating current power supply, and the protection resistor is connected between a first alternating current end and a second alternating current end of the alternating current interface; the first alternating current end and the second alternating current end of the alternating current interface are respectively connected with the first end and the second end of the voltage detection interface through the first switch; the first end and the second end of the voltage detection interface are respectively connected with the first alternating current end and the second alternating current end of the electromagnetic interference filter circuit; the first alternating current end and the second alternating current end of the electromagnetic interference filter circuit are respectively connected with the first alternating current end and the second alternating current end of the rectifier bridge; and the output end and the input end of the rectifier bridge are respectively connected with the input end and the output end of the charging circuit.

Optionally, the charging circuit includes a plurality of charging capacitors, a first detection resistor, a second detection resistor, and a load interface; the load interface, the first detection resistor and the second switch are connected in series to form a series sub-circuit, and the input end and the output end of the load interface are respectively connected with the input end and the output end of the external load; each charging capacitor is connected in parallel and is connected with the series sub-circuit in parallel to form a parallel sub-circuit; the input end of the parallel sub-circuit is connected with the output end of the rectifier bridge, the output end of the parallel sub-circuit is connected with the input end of the second detection resistor, and the output end of the second detection resistor is connected with the input end of the rectifier bridge; the second detection resistor is connected with the control circuit.

Optionally, the control circuit comprises: the device comprises a comparator, a first field effect transistor, a second field effect transistor, a first triode and a control element; a first input end of the comparator is connected with a reference signal, and a second input end of the comparator is connected with the second detection resistor in parallel; the output end of the comparator is connected with the base level of the first triode, the collector electrode of the first triode is respectively connected with the control end of the first field effect transistor, the control end of the second field effect transistor and the weak current power supply, and the emitter of the first triode is grounded; the input end and the output end of the first field effect transistor are respectively connected with the input end and the output end of the second detection resistor; the input end of the second field effect transistor is connected with the weak current power supply, the output end of the second field effect transistor is grounded, the control element is positioned between the input end of the second field effect transistor and the weak current power supply, and the first output end and the second output end of the control element are respectively connected with the first switch and the second switch.

Optionally, the device further includes a discharging circuit, connected to the charging circuit, and configured to discharge the charging circuit after the test is completed.

Optionally, the discharge circuit comprises a false touch prevention circuit and a discharge sub-circuit; the false touch prevention circuit is connected with the discharge sub-circuit and is connected with an alternating current power supply through the first switch; the discharging sub-circuit is connected with the charging circuit; when the first switch is closed, the false touch prevention circuit responds to the received alternating current to enable the discharging sub-circuit and the charging circuit to be kept disconnected, and when the first switch is disconnected, the false touch prevention circuit allows the discharging sub-circuit to be connected with the charging circuit, so that the discharging sub-circuit discharges the residual electric energy in the charging circuit.

Optionally, the false touch prevention circuit includes a second triode, and the discharge sub-circuit includes a discharge resistor, a discharge switch, and a third fet; the base stage of the second triode is connected with the alternating current power supply through the first switch; the collector of the second triode is connected with the discharge end of the charging circuit, and the emitter of the second triode is grounded; the input end of the discharge resistor is connected with the discharge end of the charging circuit, the output end of the discharge resistor is connected with the input end of the third field effect transistor, the control end of the third field effect transistor is connected with the discharge end of the charging circuit through the discharge switch, and the output end of the third field effect transistor is grounded.

Optionally, a voltage stabilizing capacitor is connected between the base stage of the second triode and the transmitter.

Optionally, a dummy load resistor is further connected between the input end and the output end of the load interface.

Optionally, the apparatus further includes a BUCK circuit, and an input end of the BUCK circuit is connected to an output end of the rectifier bridge, and is configured to output the weak current power supply.

The technical scheme provided by the utility model, following technological effect has:

the utility model provides a surge current testing device, which comprises a rectifying circuit, a charging circuit, a control circuit, a first switch and a second switch; the rectifying circuit is connected with the alternating current power supply through a first switch and connected with the charging circuit; the charging circuit is connected with an external load through a second switch; the control circuit is connected with the charging circuit and is respectively connected with the first switch and the second switch. Before the device is used for testing the load, the first switch is closed and the second switch is opened, so that the alternating current power supply outputs direct current through the rectifying circuit to charge the charging circuit. When the charging circuit is fully charged, the control circuit responds to a full-electric signal fed back by the charging circuit, the first switch is disconnected, the second switch is closed, the charging circuit stops charging and discharges instantaneously to a connected external load, and the instantaneous discharging current of the charging circuit is equivalent to the surge current generated by the large-capacity alternating current adjustable power supply, so that the function of generating large surge current by using the small-capacity alternating current adjustable power supply is realized, and the testing cost of an enterprise is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following descriptions are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 shows a schematic structural diagram of an inrush current testing device in an embodiment of the present invention;

fig. 2 shows a schematic circuit diagram of a rectifier circuit in an embodiment of the present invention;

fig. 3 shows a schematic circuit diagram of an inrush current testing device according to an embodiment of the present invention;

fig. 4 shows a schematic circuit diagram of a charging circuit in an embodiment of the invention;

fig. 5 shows a schematic circuit diagram of a control circuit in an embodiment of the invention;

fig. 6 shows a schematic structural diagram of a discharge circuit in an embodiment of the present invention;

fig. 7 shows a schematic circuit diagram of a discharge circuit in an embodiment of the invention;

fig. 8 shows a schematic circuit diagram of the BUCK circuit in an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "connected" and "abutted" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood as a specific case by those skilled in the art.

As shown in fig. 1, for the utility model provides a pair of surge current testing device, the device includes: a rectifier circuit 001, a charging circuit 002, a control circuit 003, a first switch SW1 and a second switch SW2; the rectifying circuit 001 is connected with an alternating current power supply through a first switch SW1, and the rectifying circuit 001 is connected with the charging circuit 002; the charging circuit 002 is connected to an external load through a second switch SW2; the control circuit 003 is connected to the charging circuit 002, and is connected to the first switch SW1 and the second switch SW2, respectively.

Specifically, before the surge test is performed on a load interface such as a switching power supply using the device, the first switch SW1 is closed and the second switch SW2 is opened, so that the ac power supply outputs dc power through the rectifier circuit 001, and the dc power reaches the charging circuit 002 to charge the charging circuit 002. When the charging circuit 002 is fully charged, the control circuit 003 responds to the full-charge signal fed back by the charging circuit 002 to open the first switch SW1 and close the second switch SW2, so that the charging circuit 002 is disconnected from the ac power supply to stop charging, and is connected with the external load to instantaneously discharge the connected external load. At this time, the current of the instant discharge of the charging circuit 002 is equivalent to the surge current generated by the large-capacity alternating current adjustable power supply, so that the function of generating the large surge current by using the small-capacity alternating current adjustable power supply is realized, and the test cost of enterprises is reduced.

Specifically, in an embodiment, as shown in fig. 2 and 3, the rectifier circuit 001 specifically includes: the device comprises an alternating current interface CON2, a voltage detection interface CON1, a protection resistor RV1, an electromagnetic interference filter circuit 004 and a rectifier bridge BD1; the alternating current interface CON2 is connected with an alternating current power supply, and the protection resistor RV1 is connected between a first alternating current end and a second alternating current end of the alternating current interface CON 2; a first alternating current end and a second alternating current end of the alternating current interface CON2 are respectively connected with a first end and a second end of the voltage detection interface CON1 through a first switch SW 1; a first end and a second end of the voltage detection interface CON1 are respectively connected with a first alternating current end and a second alternating current end of the electromagnetic interference filter circuit 004; a first alternating current end and a second alternating current end of the electromagnetic interference filter circuit 004 are respectively connected with a first alternating current end and a second alternating current end of the rectifier bridge BD1; the output end (pin 4 of the rectifier bridge BD 1) and the input end (pin 1 of the rectifier bridge BD 1) of the rectifier bridge BD1 are connected to the input end and the output end of the charging circuit 002, respectively.

Specifically, in the present embodiment, the external ac power source used includes, but is not limited to, 220V commercial power and a small-capacity ac adjustable power source, such as a 3KVA ac adjustable power source. The external ac power supply is connected to the ac interface CON2, and the output pins of the ac interface CON2 include 3, which are the first ac terminal, the second ac terminal, and the ground terminal (i.e., pins 3, 1, and 2 of CON2 in fig. 2). Then, a protection resistor RV1 (voltage dependent resistor is used in this embodiment) is connected between the first ac terminal and the second ac terminal of the ac interface CON2, so as to block the surge of the ac power supply and protect the following circuit structure to a certain extent. And then, the first ac terminal and the second ac terminal are provided with a synchronous first switch SW1 for synchronously closing or opening the first ac terminal and the second ac terminal, in this embodiment, the first switch SW1 is controlled by the control circuit 003 to be closed during charging and to be opened during surge testing after the charging circuit 002 is fully charged. Still be connected with voltage detection interface CON1 between two alternating current ends behind first switch SW1, this voltage detection interface CON1 is used for external voltmeter, can real-time supervision alternating current power supply's output voltage, and the tester of being convenient for adjusts the alternating current power supply of input. And then the electromagnetic interference filter circuit 004 is connected with the two alternating current ends, and the electromagnetic interference filter circuit 004 is used for filtering some high-frequency electromagnetic interference in alternating current, so that the high-frequency electromagnetic interference is prevented from being fed back to a previous-stage test instrument or equipment, and a certain protection effect is achieved. In the present embodiment, as shown in fig. 2, the electromagnetic interference filter circuit 004 is composed of two differential mode capacitors C11 and C12 and a common mode inductor L2, and is used for filtering out the differential mode electromagnetic interference and the common mode electromagnetic interference. Finally, the first ac terminal and the second ac terminal of the emi filter circuit 004 are respectively connected to the two ac terminals of the rectifier bridge BD1, so that the dc power is output to the charging circuit 002 through the rectifier bridge BD 1. In addition, in an embodiment, before the emi filter circuit 004, a resistor branch, such as R6, R9, and R10 in fig. 2, is connected between the first ac terminal and the second ac terminal, and is used to form a loop with the emi filter circuit 004 when the charging is stopped, so as to consume the residual power therein.

Specifically, in one embodiment, as shown in fig. 3 and 4, the charging circuit 002 includes several charging capacitors, a first detecting resistor R38, a second detecting resistor R4, and a load interface OUT; the load interface OUT, the first detection resistor R38 and the second switch SW2 are connected in series to form a series sub-circuit. The input end and the output end of the load interface OUT are respectively connected with the input end and the output end of an external load; each charging capacitor is connected in parallel and is connected with the series sub-circuit in parallel to form a parallel sub-circuit; the input end of the parallel sub-circuit is connected with the output end of the rectifier bridge BD1, the output end of the parallel sub-circuit is connected with the input end of the second detection resistor R4, and the output end of the second detection resistor R4 is connected with the input end of the rectifier bridge BD1; the second detection resistor R4 is connected to a detection terminal of the control circuit 003.

Specifically, in the present embodiment, the rectifier bridge BD1 outputs dc power from the output terminal (pin 4 of the rectifier bridge BD1 in fig. 3) to the charging capacitor. As shown in fig. 3, the charging capacitors are C1 to C9 connected in parallel, and the actual size and number of the charging capacitors are determined according to the magnitude of the inrush current required by the user, which is only used for example and not limited thereto in this embodiment. In addition, a series sub-circuit formed by connecting the load interface OUT, the first detection resistor R38 and the second switch SW2 in series is connected with the C1-C9 in parallel, and the output end and the input end (OUT + and OUT-) of the load interface OUT are used for being connected with an external load. When the charging capacitor is fully charged, the control circuit 003 turns off the first switch SW1 and turns on the second switch SW2. The charging capacitor, the load interface OUT, the first detection resistor R38 and the second switch SW2 form a loop, and large current in the charging capacitor is instantly released to an external load of the load interface OUT, so that large surge test current is provided for the external load, the function of providing large surge current by a small alternating current power supply is realized, and the test cost is reduced. When a user tests, a voltmeter is externally connected to two ends of the first detection resistor R38, and the actual size of the output surge current can be calculated by calculating the ratio of the measurement voltage to the first detection resistor R38, so that the user can adjust the size and the number of the charging capacitors according to actual requirements.

The parallel sub-circuit composed of the charging capacitor, the load interface OUT, the first detection resistor R38 and the second switch SW2 is connected to the second detection resistor R4, and is connected to the input end of the rectifier bridge BD1 through the second detection resistor R4. When the first switch SW1 is closed and the second switch SW2 is opened (the charging circuit 002 is in the charging process), because the voltage of the whole circuit is constant, the voltage of the charging capacitor is increased along with the charging process, the voltage on the second detection resistor R4 is reduced along with the voltage increase, at the moment, the detection end of the control circuit 003 is connected with the second detection resistor R4, whether the charging capacitor in the charging circuit 002 is fully charged is judged by measuring whether the voltage on the second detection resistor R4 is small enough, and then the first switch SW1 is opened and the second switch SW2 is closed according to the judgment result, so that the surge current is provided for the instant discharging of the load.

In addition, in an embodiment, as shown in fig. 3, dummy load resistors, such as resistors R1, R2, and R3 in the figure, are further connected between the input terminal OUT + and the output terminal OUT-of the load interface OUT, which is only an example, and the number and size of the resistors are not limited thereto. By setting the dummy load, the output voltage is stabilized and the voltage remaining in the circuit is discharged at the time of power failure.

Specifically, in one embodiment, as shown in fig. 3 and 5, the control circuit 003 includes: the device comprises a comparator U2A, a first field effect tube Q1, a second field effect tube Q3, a first triode Q2 and a control element U2. A first input end of the comparator U2A is connected with the reference signal, and a second input end of the comparator U2A is connected with the second detection resistor R4 in parallel; the output end of the comparator U2A is connected with the base level of a first triode Q2, the collector electrode of the first triode Q2 is respectively connected with a weak current power supply, the control end of a first field-effect tube Q1 and the control end of a second field-effect tube Q3, and the emitter of the first triode Q2 is grounded; the input end and the output end of the first field effect transistor Q1 are respectively connected with the input end and the output end of the second detection resistor R4; the input end of the second field effect transistor Q3 is connected with a weak current power supply, the output end of the second field effect transistor Q3 is grounded, the control element U2 is positioned between the input end of the second field effect transistor Q3 and the weak current power supply, and the first output end K1 and the second output end K2 of the control element U2 are respectively connected with the first switch SW1 and the second switch SW2.

Specifically, the present embodiment sets the control circuit 003 based on the comparator U2A, thereby detecting whether the charging capacitance in the charging circuit 002 is fully charged, and controls the first switch SW1 and the second switch SW2 in response to the full electric signal. The first input end (pin No. 2 of the comparator U2A) of the comparator U2A is connected to the reference signal, the second input end (pin No. 3) of the comparator U2A is connected in parallel to the second detection resistor R4, the specific connection position is a branch circuit composed of R5, R7, R12, and R16 in the drawing, the branch circuit is connected in parallel to the second detection resistor R4, and the voltage of the branch circuit is the same as that of the second detection resistor R4, the connection position of the second input end of the comparator U2A can be at any position among R5, R7, R12, and R16, and the connection position in the drawing is not limited to this example. The reference signal is provided with a small reference voltage by a weak current power supply in cooperation with the voltage regulator tube ZD1, and the size of the reference signal is usually about 3V, and the weak current power supply supplies power to the comparator U2A (in this embodiment, a 12V weak current power supply is adopted, and the specific size of the actual power supply is based on an actual circuit, which is only taken as an example and not limited thereto). When the charging capacitor is not fully charged, the voltage of the second input end of the comparator U2A is larger than that of the first input end, the output end of the comparator U2A outputs positive voltage, the first triode Q2 is conducted, and the weak current power supply, the control end of the first field effect tube Q1 and the control end of the second field effect tube Q3 are grounded through the emitting electrode of the first triode Q2 and are in a disconnected state. When the charging capacitor is fully charged, the voltage at the two ends of the second detection resistor R4 is reduced, the voltage of the second input end of the comparator U2A is smaller than that of the first input end, the output end of the comparator U2A outputs negative voltage, and the first triode Q2 cannot be conducted, so that the control ends of the first field effect transistor Q1 and the second field effect transistor Q3 are conducted with a weak power supply, the first field effect transistor Q1 and the second field effect transistor Q3 start to work, the input end and the output end of the first field effect transistor Q1 are conducted, the second detection resistor R4 is in short circuit, the second detection resistor R4 stops heating in time, and risks such as scalding users are avoided. In this embodiment, the second detection resistor R4 is an adjustable resistor, so that the user can flexibly adjust the charging time period. Meanwhile, the input end and the output end of the second field effect transistor Q3 are connected, so that the weak current power supply can supply power to the control element U2, the control element U2 starts to work, controls the first switch SW1 to be disconnected through the pin K1 and controls the second switch SW2 to be closed through the pin K2, and the charging circuit 002 supplies surge current to the load. In addition, in an embodiment, the control element U2 is also connected in series with a light emitting diode D4 for prompting the user to charge the circuit 002 to be full, and if the control element U2 fails, the user can be informed to open the first switch SW1 and close the second switch SW2 manually.

In addition, in the embodiment, the comparator U2A is a hysteresis comparator U2A composed of a chip U2A, a resistor R19/R20/R18 and a voltage regulator tube ZD1, and compared with a common comparator, the problem that the output end is turned over too frequently when the voltage fluctuates is avoided. The resistors R11, R17, R22 and R23 are used for current limiting and voltage dividing.

Specifically, in an embodiment, the embodiment of the utility model provides an inrush current testing arrangement still includes discharge circuit 005, and discharge circuit 005 is connected with charging circuit 002 for discharge to charging circuit 002 after the test is accomplished.

Specifically, as shown in fig. 6, the discharge circuit 005 provided in the embodiment of the present invention specifically includes a false touch prevention circuit 007 and a discharge sub-circuit 008; the false touch prevention circuit 007 is connected with the discharge sub-circuit 008, and the false touch prevention circuit 007 is connected with an alternating current power supply through a first switch SW 1; the electronic discharge circuit 008 is connected with the charging circuit 002; when the first switch SW1 is closed, the false touch prevention circuit 007 responds to the received alternating current to keep the connection between the discharging sub-circuit 008 and the charging circuit 002, and when the first switch SW1 is open, the false touch prevention circuit 007 allows the discharging sub-circuit 008 to be connected with the charging circuit 002, so that the discharging sub-circuit 008 discharges the residual electric energy in the charging circuit 002.

Specifically, as shown in fig. 3 and 7, in the present embodiment, the false touch protection circuit 007 includes at least a second transistor Q5, and may further include a shaping diode D5, current limiting resistors R31, R32, R33, and R34, and a voltage stabilizing capacitor C19. The discharge circuit 008 at least includes a discharge resistor R39, a discharge switch S3, a third field effect transistor Q4, and may further include current limiting resistors R35, R36, R37, R21, R25, R26, a second voltage regulator tube ZD2, and a second protection resistor R30. The base stage of the second triode Q5 is connected with an alternating current power supply through a first switch SW 1; the collector of the second triode Q5 is connected with the discharge end of the charging circuit 002, and the emitter of the second triode Q5 is grounded; the input end of the discharging resistor R39 is connected with the discharging end of the charging circuit 002, the output end of the discharging resistor R39 is connected with the input end of the third field-effect tube Q4, the control end of the third field-effect tube Q4 is connected with the discharging end of the charging circuit 002 through the discharging switch S3, and the output end of the third field-effect tube Q4 is grounded.

Specifically, the discharge principle of the present embodiment is as follows:

when the surge test is finished, the first switch SW1 is in an off state. The user presses the discharging switch S3 to connect the discharging terminal HV of the charging circuit 002 with the control terminal of the third fet Q4, and turns on the third fet Q4. And then the charging circuit 002 forms a loop with the ground through the discharging resistor R39, the electric energy is converted into the heat energy of the discharging resistor R39, the residual electric quantity in the charging circuit 002 is consumed, and the result of the next surge test is ensured to be accurate. The current limiting resistors R35, R36, R37, R21, R25 and R26 and the second voltage regulator tube ZD2 are used for avoiding the overlarge current of the control end of the third field effect tube Q4 and protecting the third field effect tube Q4. The second protection resistor R30 is grounded to avoid the virtual connection of the third field effect transistor Q4 when the third field effect transistor Q4 is not discharging, and even if a weak current is generated at the discharging switch S3, the control terminal of the third field effect transistor Q4 does not receive a current signal, but flows into the ground through the second protection resistor R30.

Specifically, the principle of the false touch prevention circuit 007 of the present embodiment is as follows:

when the first switch SW1 is closed, the charging circuit 002 is in the charging process, the alternating current can be changed into discontinuous direct current through the shaping diode D5 to reach the base level of the second triode Q5, the discontinuous direct current is stabilized through the second voltage regulator tube ZD2, so that the collector and emitter of the second triode Q5 are conducted, when the second triode Q5 is conducted, the discharging end HV of the charging circuit 002 is directly grounded, the charging loop is still maintained, even if the discharging switch S3 is pressed, the current can flow into the ground through the second triode Q5, the third field effect tube Q4 cannot be conducted, and therefore the charging capacitor cannot be discharged in the charging process. Only when the first switch SW1 is turned off, no ac power is input, the second transistor Q5 is not turned on, and the third fet Q4 is enabled by pressing the discharge switch S3. On one hand, the charging capacitor is ensured not to be insufficiently charged due to repeated charging and discharging, and on the other hand, the safety is improved.

Specifically, in an embodiment, as shown in fig. 8, the inrush current testing device provided in an embodiment of the present invention further includes a BUCK circuit 006, an input terminal of the BUCK circuit 006 is connected to an output terminal (in this embodiment, equivalent to the discharge terminal HV of the charging circuit 002) of the rectifier bridge BD1, and is used for outputting a weak current power supply.

Specifically, in the present embodiment, the BUCK circuit 006 is provided and includes a field effect chip U1, a capacitor C13/C14/C15/C16, an inductor L1, and a diode D1/D3, and the specific operation principle thereof is the prior art and is not described herein again. Step down the high voltage direct current of rectifier bridge BD1 output through BUCK circuit 006, the required 12V weak current power supply of this embodiment of output to for comparator U2A and each bias circuit power supply, need not the outside and provide weak current power supply and also need not the battery, further improve surge current testing arrangement's practicality.

The utility model has the advantages that:

the utility model provides a surge current testing device, including rectifier circuit 001, charging circuit 002, control circuit 003, first switch SW1 and second switch SW2; the rectifying circuit 001 is connected with an alternating current power supply through a first switch SW1, and the rectifying circuit 001 is connected with the charging circuit 002; the charging circuit 002 is connected to an external load through a second switch SW2; the control circuit 003 is connected to the charging circuit 002, and is connected to the first switch SW1 and the second switch SW2, respectively. Before the device is used for testing the load, the first switch SW1 is closed and the second switch SW2 is opened, so that the alternating current power supply outputs direct current through the rectifying circuit 001 to charge the charging circuit 002. When the charging circuit 002 is fully charged, the control circuit 003 responds to the full-charge signal fed back by the charging circuit 002, and opens the first switch SW1 and closes the second switch SW2, so that the charging circuit 002 stops charging and instantaneously discharges to the connected external load, and the instantaneous discharging current of the charging circuit 002 is equivalent to the surge current generated by the large-capacity alternating current adjustable power supply, thereby realizing the function of generating large surge current by using the small-capacity alternating current adjustable power supply, and reducing the testing cost of enterprises.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. An inrush current testing device, the device comprising:

the charging circuit comprises a rectifying circuit, a charging circuit, a control circuit, a first switch and a second switch;

the rectifying circuit is connected with an alternating current power supply through a first switch, and the rectifying circuit is connected with the charging circuit;

the charging circuit is connected with an external load through a second switch;

the control circuit is connected with the charging circuit and is respectively connected with the first switch and the second switch;

when the first switch is closed and the second switch is opened, the alternating current power supply outputs direct current through the rectifying circuit so as to charge the charging circuit, and when the charging circuit is fully charged, the control circuit responds to a full electric signal fed back by the charging circuit, opens the first switch and closes the second switch so as to discharge the charging circuit and provide surge current for the external load.

2. The apparatus of claim 1, wherein the rectification circuit comprises: the device comprises an alternating current interface, a voltage detection interface, a protection resistor, an electromagnetic interference filter circuit and a rectifier bridge;

the alternating current interface is connected with the alternating current power supply, and the protection resistor is connected between a first alternating current end and a second alternating current end of the alternating current interface;

the first alternating current end and the second alternating current end of the alternating current interface are respectively connected with the first end and the second end of the voltage detection interface through the first switch;

the first end and the second end of the voltage detection interface are respectively connected with the first alternating current end and the second alternating current end of the electromagnetic interference filter circuit;

the first alternating current end and the second alternating current end of the electromagnetic interference filter circuit are respectively connected with the first alternating current end and the second alternating current end of the rectifier bridge;

and the output end and the input end of the rectifier bridge are respectively connected with the input end and the output end of the charging circuit.

3. The apparatus of claim 2, wherein the charging circuit comprises a plurality of charging capacitors, a first detection resistor, a second detection resistor, and a load interface;

the load interface, the first detection resistor and the second switch are connected in series to form a series sub-circuit, and the input end and the output end of the load interface are respectively connected with the input end and the output end of the external load;

each charging capacitor is connected in parallel and is connected with the series sub-circuit in parallel to form a parallel sub-circuit;

the input end of the parallel sub-circuit is connected with the output end of the rectifier bridge, the output end of the parallel sub-circuit is connected with the input end of the second detection resistor, and the output end of the second detection resistor is connected with the input end of the rectifier bridge;

the second detection resistor is connected with the control circuit.

4. The apparatus of claim 3, wherein the control circuit comprises: the device comprises a comparator, a first field effect transistor, a second field effect transistor, a first triode and a control element;

a first input end of the comparator is connected with a reference signal, and a second input end of the comparator is connected with the second detection resistor in parallel;

the output end of the comparator is connected with the base level of the first triode, the collector electrode of the first triode is respectively connected with the control end of the first field effect transistor, the control end of the second field effect transistor and the weak current power supply, and the emitter of the first triode is grounded;

the input end and the output end of the first field effect transistor are respectively connected with the input end and the output end of the second detection resistor;

the input end of the second field effect transistor is connected with the weak current power supply, the output end of the second field effect transistor is grounded, the control element is positioned between the input end of the second field effect transistor and the weak current power supply, and the first output end and the second output end of the control element are respectively connected with the first switch and the second switch.

5. The apparatus of claim 1 or 4, further comprising a discharge circuit coupled to the charging circuit for discharging the charging circuit after the test is completed.

6. The apparatus of claim 5, wherein the discharge circuit comprises a false touch prevention circuit and a discharge sub-circuit;

the false touch prevention circuit is connected with the discharge sub-circuit and is connected with an alternating current power supply through the first switch;

the discharging sub-circuit is connected with the charging circuit;

when the first switch is closed, the false touch prevention circuit responds to the received alternating current to enable the discharge sub-circuit and the charging circuit to be kept disconnected, and when the first switch is disconnected, the false touch prevention circuit allows the discharge sub-circuit to be connected with the charging circuit, so that the discharge sub-circuit discharges the residual electric energy in the charging circuit.

7. The apparatus of claim 6, wherein the anti-false-touch circuit comprises a second transistor, and the discharge sub-circuit comprises a discharge resistor, a discharge switch, and a third FET;

the base stage of the second triode is connected with the alternating current power supply through the first switch;

the collector of the second triode is connected with the discharge end of the charging circuit, and the emitter of the second triode is grounded;

the input end of the discharge resistor is connected with the discharge end of the charging circuit, the output end of the discharge resistor is connected with the input end of the third field effect transistor, the control end of the third field effect transistor is connected with the discharge end of the charging circuit through a discharge switch, and the output end of the third field effect transistor is grounded.

8. The apparatus of claim 7, wherein a voltage stabilizing capacitor is connected between the base of the second transistor and the transmitter.

9. The apparatus of claim 3, wherein a dummy load resistor is connected between the input and output of the load interface.

10. The apparatus of claim 4, further comprising a BUCK circuit having an input connected to the output of the rectifier bridge for outputting the weak current power supply.