CN216387328U

CN216387328U - Oscilloscope port expansion control equipment for power supply ripple test

Info

Publication number: CN216387328U
Application number: CN202122797345.2U
Authority: CN
Inventors: 王道金
Original assignee: Sichuan Jiuzhou Electric Group Co Ltd
Current assignee: Sichuan Jiuzhou Electric Group Co Ltd
Priority date: 2021-11-15
Filing date: 2021-11-15
Publication date: 2022-04-26
Anticipated expiration: 2031-11-15

Abstract

The utility model relates to an oscilloscope port expansion control device for power supply ripple test, belongs to the technical field of power supply test, and solves the problems that in the existing power supply ripple test, because the input ports of an oscilloscope are fewer, the test efficiency is lower, the cost is higher, and the requirement of power supply ripple automatic test of multi-path output cannot be met. The circuit comprises a case, wherein a control circuit printed board is arranged in the case, and a switch matrix circuit, a first serial port circuit and a micro control unit circuit are packaged on the control circuit printed board; the output ends of the micro-control unit circuits are respectively connected with the control ends of the switch matrix circuit, the first serial input end is connected with the output end of the first serial port circuit, and the first serial output end is connected with the input end of the first serial port circuit; and each load connection end of the switch matrix circuit is connected with an expansion input port arranged on the case and is used for connecting each output end to be tested of the power supply to be tested, and the output end of the switch matrix circuit is connected with an expansion output port arranged on the case and is used for connecting the input end of the oscilloscope.

Description

Oscilloscope port expansion control equipment for power supply ripple test

Technical Field

The utility model relates to the technical field of power supply testing, in particular to an oscilloscope port expansion control device for power supply ripple testing.

Background

With the development of electronic products, a power supply is an indispensable part of many electronic products, and a dc power supply is a more common power supply. When a system is designed, in order to shorten a design period, an AC to DC power supply and a DC to DC power supply are generally packaged, and a required use type is directly selected when the system is designed. The output voltage ripple is an important index for considering the output voltage of the DC stabilized voltage supply, the ripple is not large, the performance of the power utilization circuit is directly influenced, the power efficiency is reduced in severe cases, surge voltage or current is generated, the power utilization equipment is burnt, the logic relation of a digital circuit is interfered, and the normal work of the equipment is influenced.

In the batch production test process of the power supply module, when the power supply module has multiple output ends, each output end needs to be connected with the input end of the oscilloscope respectively to test the output ripple waves, and due to the limitation of the number of the input ports of the oscilloscope, the process needs manual switching, so that the speed is low, the efficiency is low, errors are easily caused, and the test result is inaccurate; if the output ends of each power supply module are connected with the input ends of a plurality of oscilloscopes, the purchasing cost is increased, and the resource waste is caused.

In summary, the existing power supply ripple test has the disadvantages of low test efficiency and high cost due to the fact that the number of input ports of the oscilloscope is small, and the requirement of power supply ripple automatic test of multi-path output cannot be met.

SUMMERY OF THE UTILITY MODEL

In view of the foregoing analysis, the present invention aims to provide an oscilloscope port expansion control device for power supply ripple test, so as to solve the problems that in the existing power supply ripple test, because the number of input ports of an oscilloscope is small, the test efficiency is low, the cost is high, and the requirement of power supply ripple automatic test of multi-output cannot be met.

The purpose of the utility model is mainly realized by the following technical scheme:

the utility model discloses an oscilloscope port expansion control device for power supply ripple test, which comprises a case, wherein a control circuit printed board is arranged in the case, and a switch matrix circuit, a first serial port circuit and a micro control unit circuit are packaged on the control circuit printed board;

the micro control unit circuit comprises a plurality of output ends, each output end is respectively connected with each control end of the switch matrix circuit, a first serial input end is connected with the output end of the first serial port circuit, and the first serial output end is connected with the input end of the first serial port circuit;

each load connection end of the switch matrix circuit is connected with an expansion input port arranged on the case and is used for connecting each output end to be tested of a power supply to be tested, and the output end of the switch matrix circuit is connected with an expansion output port arranged on the case and is used for connecting the input end of an oscilloscope;

a receiving end of the first serial port circuit is connected with a 3 rd pin of a first D-type data interface connector arranged on the case; the transmitting end is connected with the 4 th pin of the first D-type data interface connector;

the output end of the micro control unit circuit, the control end of the switch matrix circuit and the load connecting end of the switch matrix circuit are in one-to-one correspondence.

Furthermore, the switch matrix circuit comprises a plurality of switch sub-circuits, each switch sub-circuit has the same structure and comprises an NPN type triode and a normally open relay;

the base electrode of the NPN type triode is the control end of the switch sub-circuit, the emitting electrode of the NPN type triode is grounded, and the collecting electrode of the NPN type triode is connected with one end of the normally open relay coil; the other end of the normally open relay coil is connected with a first power supply, the first contact is the output end of the switch sub-circuit, and the second contact is the load connecting end of the switch sub-circuit.

Further, the switch sub-circuit further comprises a first resistor, a capacitor and a diode;

one end of the first resistor is connected with the base electrode of the NPN type triode, and the other end of the first resistor is the control end of the switch sub-circuit; one end of the capacitor is connected with the second contact of the normally open relay, and the other end of the capacitor is grounded; and the anode of the diode is connected with the collector of the NPN type triode, and the cathode of the diode is connected with the other end of the normally open relay coil.

Further, the switch sub-circuit further comprises a second resistor;

one end of the second resistor is connected with a collector of the NPN type triode, the other end of the second resistor is connected with a negative electrode of a port indicator light LED arranged on the case, and a positive electrode of the port indicator light LED is connected with the other end of the normally open relay coil.

Further, the first serial port circuit comprises a MAX485 chip, resistors R3-R7 and R30, capacitors C16 and C17, an inductor L3 and a PNP type triode Q1;

the pin 1 at the output end of the MAX485 chip is the output end of the first serial port circuit; the pin 4 at the input end is the input end of the first serial port circuit, and the pin 4 at the input end is also connected with the base electrode of a PNP type triode Q1 after passing through a resistor R5; a pin 3 of the receiving enabling end is connected with one end of a resistor R7 and is also connected with a collector of a PNP type triode Q1; the pin 2 of the sending enabling end is connected with the pin 3 of the receiving enabling end; the ground terminal 5 is grounded; a pin 6 of the differential signal receiving end is a receiving end of the first serial port circuit, and the pin 6 of the differential signal receiving end is also connected with one end of a resistor R6 and one end of a resistor R4; the pin 7 of the differential signal sending end is a sending end of the first serial port circuit, and the pin 7 of the differential signal sending end is also connected with the other end of the resistor R4 and one end of the resistor R3; the power supply end 8 pin is connected with one end of the inductor L3 and one end of the capacitor C17;

an emitter of the PNP type triode Q1 is connected with one end of the resistor R30; the other end of the resistor R6 and the other end of the resistor R30 are connected with a second power supply; the other end of the inductor L3 is connected with one end of the capacitor C16 and is also connected with a second power supply; the other ends of the capacitor C16, the capacitor C17, the resistor R7 and the resistor R3 are grounded.

Furthermore, a second serial port circuit is also arranged on the control circuit printed board; the receiving end of the second serial port circuit is connected with the 3 rd pin of a second D-type data interface connector arranged on the case, the sending end is connected with the 2 nd pin of the second D-type data interface connector, the output end is connected with the second serial input end of the micro control unit circuit, and the input end is connected with the second serial output end of the micro control unit circuit.

Further, the second serial port circuit comprises a MAX232 chip, capacitors C10-C15 and an inductor L2;

a pin 11 of a data input end of the MAX232 chip is an input end of the second serial port circuit, a pin 12 of a data output end of the MAX232 chip is an output end of the second serial port circuit, a pin 13 of a signal input end of the MAX232 chip is a receiving end of the second serial port circuit, a pin 14 of the signal output end of the MAX232 chip is a sending end of the second serial port circuit, a pin 15 of a grounding end is grounded, a pin 16 of a power supply end is connected with one end of a capacitor C12 and one end of an inductor L2, a pin 2 of the power supply end is connected with a pin 16 of the power supply end after passing through a capacitor C11, a pin 1 of the power supply end is connected with a pin 3 after passing through a capacitor C13, a pin 4 of the power supply end is connected with a pin 5 after passing through a capacitor C14, and a pin 6 of the power supply end is grounded after passing through a capacitor C15;

the other end of the inductor L2 is connected with one end of the capacitor C10 and is also connected with a second power supply; the other ends of the capacitor C10 and the capacitor C12 are grounded.

Furthermore, a power supply circuit is also arranged on the control circuit printed board, and the input end of the power supply circuit is connected with a power supply input port arranged on the case and used for being connected with a first power supply; the output end is used for providing a second power supply.

Further, the power supply circuit comprises capacitors C1, C3-C5 and a voltage stabilizing chip;

the input end of the voltage stabilizing chip is the input end of the power supply circuit, and the output end of the voltage stabilizing chip provides a second power supply; the input end of the voltage stabilizing chip is also connected with one ends of capacitors C1 and C3, and the output end of the voltage stabilizing chip is also connected with one ends of capacitors C4 and C5; the other ends of the capacitors C1 and C3-C5 are grounded.

Further, the power supply circuit further comprises a resistor R1;

the input end of the voltage stabilizing chip is connected with the anode of a power indicator LED1 arranged on the case, and the cathode of the power indicator LED1 is grounded after passing through a resistor R1; the input end of the voltage stabilizing chip is also connected with one end of a fuse F1 arranged on the case, the other end of the fuse F1 is connected with one end of a power switch SW1 arranged on the case, and the other end of the power switch SW1 is connected with a power input port arranged on the case.

Compared with the prior art, the utility model can realize the following beneficial effects:

the utility model provides an oscilloscope port expansion control device for power supply ripple test,

the switch matrix circuit on the control circuit printed board in the case is connected with each output end to be tested of the power supply module to be tested and the input end of the oscilloscope, the micro control unit circuit is communicated with the upper computer through the first serial port circuit, and then the switch matrix circuit is controlled to switch the output end to be tested which is connected with the input end of the oscilloscope, so that the inaccuracy of test data caused by switching errors due to manual switching of each output end is avoided, the switching speed and the switching accuracy are greatly improved, the test efficiency is improved, and the test cost is reduced.

In the utility model, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the utility model will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model. The objectives and other advantages of the utility model may be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the utility model, wherein like reference numerals are used to designate like parts throughout.

Fig. 1 is a schematic structural diagram of a control circuit printed board in an oscilloscope port expansion control device for power supply ripple test provided by the utility model;

FIG. 2 is a schematic front view of an oscilloscope port expansion control equipment chassis for power supply ripple test provided by the present invention;

2(a), (b), (c) are a front view schematic diagram, a top view schematic diagram and a left view schematic diagram of the oscilloscope port expansion control device for power supply ripple test provided by the utility model;

fig. 3 is a schematic connection diagram of a first serial port circuit on a control circuit printed board according to the present invention;

fig. 4 is a schematic connection diagram of a second serial port circuit on the control circuit printed board provided by the utility model;

fig. 5 is a schematic connection diagram of a power supply circuit on the control circuit printed board provided by the present invention;

FIG. 6 is a schematic connection diagram of a switch matrix circuit of a 2-group 4-port input expansion control device provided by the present invention;

fig. 7 is a schematic connection diagram of a micro control unit circuit of a 2-group 4-port input expansion control device provided by the utility model.

Reference numerals:

1-an expansion output port; 2-connecting wires; 3-an indicator light; 4-control the circuit printed board; 5-a ground port; 6-power input port; 7-a fuse; 8-power switch; 9-a second type-D data interface connector; 10-a first type D data interface connector; 11-extended input port; 12-case.

Detailed Description

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the utility model and together with the description, serve to explain the principles of the utility model and not to limit the scope of the utility model.

The utility model discloses an oscilloscope port expansion control device for power supply ripple test, which comprises a case 12 as shown in fig. 2, wherein a control circuit printed board 4 is arranged in the case 12, and a switch matrix circuit, a first serial port circuit and a micro control unit circuit are packaged on the control circuit printed board as shown in fig. 1.

The micro control unit circuit comprises a plurality of output ends, each output end is connected with each control end of the switch matrix circuit, the first serial input end is connected with the output end of the first serial port circuit, and the first serial output end is connected with the input end of the first serial port circuit.

Specifically, the micro control unit circuit adopts an STC single chip microcomputer, and an oscillation and reset circuit is arranged in the micro control unit circuit and is used for resetting the micro control unit circuit when the control equipment is powered on and started.

And each load connection end of the switch matrix circuit is connected with an expansion input port arranged on the case and is used for connecting each output end to be tested of a power supply to be tested, and the output end of the switch matrix circuit is connected with an expansion output port arranged on the case and is used for connecting the input end of an oscilloscope.

Specifically, the expansion input port and the expansion output port are connected by a BNC connector and arranged on the outer surface of the case, and when the expansion input port and the expansion output port are connected with the output end to be tested of the power module to be tested or the input end of the oscilloscope, the expansion input port and the expansion output port are connected by a radio frequency cable with the BNC connector.

A receiving end of the first serial port circuit is connected with a 3 rd pin of a first D-type data interface connector 10 arranged on the case; the transmitting end is connected with the 4 th pin of the first D-type data interface connector 10; the remote control device is used for communicating with an upper computer and carrying out remote control.

Specifically, the first D-type data interface connector 10 is a 9-pin D-type interface connector DB9, and the 5 th pin of the first D-type data interface connector is grounded.

The micro control unit circuit is communicated with an upper computer (computer) through a first serial port circuit based on a serial protocol, receives a control instruction sent by the upper computer, converts the control instruction into high and low level signals and outputs the high and low level signals to each control end of the switch matrix circuit through the output end respectively to realize port switching, connects the output end of the power supply to be tested with the input end of the oscilloscope, and transmits the control result of the switch matrix circuit back to the upper computer, so that the ripple test of the multi-path output end of the power supply to be tested is realized. The program of the micro control unit circuit for generating the high and low level signals corresponding to the output ends according to the upper computer control instruction is the prior art, and the existing mode of converting the upper computer instruction into the high and low level signals is only required to be operated in the micro control unit circuit, and the utility model is not specifically explained here, and does not relate to any software improvement.

In implementation, the switch matrix circuit comprises a plurality of switch sub-circuits, each of which has the same structure and comprises an NPN-type triode Q2 and a normally open relay JT 1; the number of the switch sub-circuits can be set according to the use requirement, namely the control equipment can be expanded according to the actual test condition.

The base electrode of the NPN type triode Q2 is the control end of the switch sub circuit, the emitting electrode is grounded, and the collecting electrode is connected with one end of the JT1 coil of the normally open relay; the other end of the normally open relay JT1 coil is connected with a first power supply, the first contact is the output end of the switch sub-circuit, and the second contact is the load connection end of the switch sub-circuit.

During specific implementation, if the control end of the switch sub-circuit receives a high level signal, the control voltage of the control end of the switch sub-circuit is regulated to be high level, and the first contact and the second contact of the normally open relay are closed, so that the output end to be tested connected with the load connection end of the sub-circuit is conducted with the input end of the oscilloscope; if the control end of the switch sub-circuit receives a low level signal, the control voltage of the control end of the switch sub-circuit is regulated to be low level, and the first contact and the second contact of the normally open relay are disconnected, so that the output end to be tested connected with the load connection end of the sub-circuit is disconnected with the input end of the oscilloscope; that is to say, can accomplish the switching of the output that awaits measuring of the power that awaits measuring through switch matrix circuit, avoid the manual work to switch, it is more accurate, efficiency is higher.

Preferably, the switch sub-circuit further comprises a first resistor R12, a capacitor C18 and a diode D2;

one end of the first resistor R12 is connected with a base Q2 of the NPN type triode and used for limiting current, and the other end of the first resistor R12 is a control end of the switch sub circuit; one end of the capacitor C18 is connected with the second contact of the normally open relay JT1, and the other end of the capacitor C18 is grounded and used for high-frequency filtering and filtering out high-frequency clutter interference in a test loop; the anode of the diode is connected with the collector of the NPN type triode Q2, and the cathode of the diode is connected with the other end of the coil of the normally open relay JT1, so that the NPN type triode Q2 is prevented from being burnt out by directional voltage when the normally open relay JT1 is powered off.

Preferably, the switch sub-circuit further comprises a second resistor R8;

one end of the second resistor R8 is connected to the collector of the NPN transistor Q2, the other end of the second resistor R8 is connected to the negative electrode of a port indicator LED disposed on the chassis, and the positive electrode of the port indicator LED is connected to the other end of the normally open relay JT1 coil. The port indicator light LED is used for indicating the on-off of the switch sub-circuit, and if the current switch sub-circuit is switched on, the port indicator light LED is turned on.

Preferably, the anode of the port indicator LED is also connected to a fuse 7 provided on the light box.

In implementation, as shown in fig. 3, the first serial port circuit includes a MAX485 chip, resistors R3-R7, R30, capacitors C16, C17, an inductor L3, and a PNP transistor Q1;

the pin 1 at the output end of the MAX485 chip is the output end of the first serial port circuit; the pin 4 at the input end is the input end of the first serial port circuit, and the pin 4 at the input end is also connected with the base electrode of a PNP type triode Q1 after passing through a resistor R5; a pin 3 of the receiving enabling end is connected with one end of a resistor R7 and is also connected with a collector of a PNP type triode Q1; the pin 2 of the sending enabling end is connected with the pin 3 of the receiving enabling end; the ground terminal 5 is grounded; a pin 6 of the differential signal receiving end is a receiving end of the first serial port circuit, and the pin 6 of the differential signal receiving end is also connected with one end of a resistor R6 and one end of a resistor R4; the pin 7 of the differential signal sending end is a sending end of the first serial port circuit, and the pin 7 of the differential signal sending end is also connected with the other end of the resistor R4 and one end of the resistor R3; the power supply end 8 pin is connected with one end of the inductor L3 and one end of the capacitor C17; an emitter of the PNP type triode Q1 is connected with one end of the resistor R30; the other end of the resistor R6 and the other end of the resistor R30 are connected with a second power supply; the other end of the inductor L3 is connected with one end of the capacitor C16 and is also connected with a second power supply; the other ends of the capacitor C16, the capacitor C17, the resistor R7 and the resistor R3 are grounded. The resistors R5, R7, R30 and the PNP type triode Q1 realize half-duplex communication between the first serial port circuit and an upper computer; the resistors R3, R4 and R6 are terminal matching resistors, so that the stability and reliability of data transmission are improved; the inductor L3 and the capacitors C16 and C17 are used for power supply filtering.

When the control circuit is implemented, a second serial port circuit is also arranged on the control circuit printed board; the receiving end of the second serial port circuit is connected with the 3 rd pin of a second D-type data interface connector 9 arranged on the case, the sending end is connected with the 2 nd pin of the second D-type data interface connector 9, the output end is connected with the second serial input end of the micro control unit circuit, and the input end is connected with the second serial output end of the micro control unit circuit.

Specifically, the second D-type data interface connector 9 is a 9-pin D-type interface connector DB9, and the 5 th pin of the second D-type data interface connector is grounded.

It can be understood that the upper computer performs program programming to the micro control unit circuit through the second serial port circuit based on the serial protocol, and is used for controlling the upgrading of the device program; the micro control unit circuit performs program programming according to the upper computer control instruction, which is the prior art, and the existing program programming mode is operated in the micro control unit circuit, which is not specifically described herein, and the utility model does not relate to any software improvement.

Specifically, as shown in fig. 4, the second serial port circuit includes a MAX232 chip, capacitors C10-C15, and an inductor L2;

a pin 11 of a data input end of the MAX232 chip is an input end of the second serial port circuit, a pin 12 of a data output end of the MAX232 chip is an output end of the second serial port circuit, a pin 13 of a signal input end of the MAX232 chip is a receiving end of the second serial port circuit, a pin 14 of the signal output end of the MAX232 chip is a sending end of the second serial port circuit, a pin 15 of a grounding end is grounded, a pin 16 of a power supply end is connected with one end of a capacitor C12 and one end of an inductor L2, a pin 2 of the power supply end is connected with a pin 16 of the power supply end after passing through a capacitor C11, a pin 1 of the power supply end is connected with a pin 3 after passing through a capacitor C13, a pin 4 of the power supply end is connected with a pin 5 after passing through a capacitor C14, and a pin 6 of the power supply end is grounded after passing through a capacitor C15; the other end of the inductor L2 is connected with one end of the capacitor C10 and is also connected with a second power supply; the other ends of the capacitor C10 and the capacitor C12 are grounded. The inductor L2 and the capacitors C10 and C12 are used for power supply filtering.

In implementation, the control circuit printed board is also provided with a power supply circuit, and the input end of the power supply circuit is connected with a power input port arranged on the case and used for being connected with a first power supply; the output end is used for providing a second power supply.

Specifically, the first power supply is 12V, and the second power supply is 5V.

Specifically, as shown in fig. 5, the power supply circuit includes capacitors C1, C3-C5 and a voltage stabilization chip;

the input end of the voltage stabilizing chip is the input end of the power supply circuit, and the output end of the voltage stabilizing chip provides a second power supply; the input end of the voltage stabilizing chip is also connected with one ends of capacitors C1 and C3, and the output end of the voltage stabilizing chip is also connected with one ends of capacitors C4 and C5; the other ends of the capacitors C1 and C3-C5 are grounded. Wherein, C1 and C3 are input filter capacitors; c4 and C5 are output filter capacitors;

preferably, the power supply circuit further comprises a resistor R1;

the input end of the voltage stabilizing chip is connected with the anode of a power indicator LED1 arranged on the case, and the cathode of the power indicator LED1 is grounded after passing through a resistor R1; the input end of the voltage stabilizing chip is also connected with one end of a fuse F1 arranged on the case, the other end of the fuse F1 is connected with one end of a power switch SW1 arranged on the case, and the other end of the power switch SW1 is connected with a power input port arranged on the case. Wherein, R1 current limiting resistor; the power switch SW1 is used for controlling whether the control equipment is powered on or not, when the power switch SW1 is closed, the control equipment is powered on and started, and when the power switch SW1 is disconnected, the control equipment is powered off and closed; the fuse F1 is used for preventing the internal short circuit of the control equipment and protecting the safety of the control equipment; the power indicator LED1 is used for indicating whether the control device is powered on, and if the control device is powered on, the power indicator LED1 is turned on.

Preferably, the chassis is further provided with a ground port 5, and the control device is connected with the ground through a ground wire, so that the control device is prevented from being burnt out by static electricity.

For example, in this embodiment, a port expansion control device with 2 groups of 4 ports is taken as an example, as shown in fig. 7, an STC single-chip microcomputer U2 adopted by a micro-control unit circuit is STC15W4K32S4-28I-LQFP64S, and a pin 27 of a second serial port input end is connected with an output end of a second serial port circuit; the pin 28 of the second serial port output end is connected with the input end of the second serial port circuit; the pin 35 of the first serial port input end is connected with the output end of the first serial port circuit; the pin 36 of the first serial port output end is connected with the input end of the first serial port circuit; the 37 th to 40 th and 53 th to 56 th pins of the IO port are used as the output end of the micro control unit circuit and are respectively connected with each control end of the switch matrix circuit, namely the control end of each switch sub-circuit; the power supply terminal 19 pin is connected with one end of the inductor L1 and one end of the capacitor C9; the ground terminal 21 is grounded; the other end of the inductor L1 is connected with a second power supply and is also connected with one end of a capacitor C8; the other ends of the capacitor C8 and the capacitor C9 are connected with the grounding end of the 21 st pin of the STC singlechip U2; the pin 26 is connected with one end of the resistor R2, the other end of the resistor R2 is connected with the negative electrode of the work indicator light LED2 arranged on the machine box, and the positive electrode of the work indicator light LED2 is connected with the second power supply. Wherein, the resistor R2 is a current-limiting resistor; the inductor L1 and the capacitors C8 and C9 are used for power supply filtering; the work indicator light LED2 is used for indicating whether the control equipment works normally, and if the current control equipment works normally, the work indicator light LED2 flickers.

As shown in fig. 6, a wiring diagram of the switch matrix circuit is a four-way switch matrix circuit corresponding to the oscilloscope port 1 and formed by normally open relays JT1-JT4, wherein second contacts of 4 normally open relays are used as load connection terminals for being connected with the output terminal to be tested of the power supply to be tested, and then are connected with the 37 th to 40 th pins of the STC singlechip U2 through resistors R12, R13, R14 and R15, respectively, so as to receive high and low level signals switched by the corresponding output terminal to be tested; the four-way switch matrix circuit corresponding to the oscilloscope port 2 is composed of normally open relays JT5-JT8, second contacts of 4 normally open relays are used as load connection ends and are used for being connected with output ends to be tested of a power supply to be tested respectively, and then the second contacts are connected with pins 53-56 of an STC single chip microcomputer U2 through resistors R20, R21, R22 and R23 respectively to receive high and low level signals switched by corresponding output ends to be tested.

Compared with the prior art, the oscilloscope port expansion control equipment for power supply ripple test provided by the embodiment is characterized in that the switch matrix circuit on the control circuit printed board in the case is connected with each output end to be tested of the power supply module to be tested and the input end of the oscilloscope, the micro control unit circuit is communicated with the upper computer through the first serial port circuit, and then the switch matrix circuit is controlled to switch the output ends to be tested which are connected with the input end of the oscilloscope, the inaccuracy of test data caused by switching errors due to manual switching of each output end is avoided, the switching speed and the switching accuracy are greatly improved, the test efficiency is improved, and the test cost is reduced.

It can be understood by those skilled in the art that the programs related to the mcu circuit in the above embodiments are common methods in the prior art, such as converting the existing upper computer instructions into high and low level signals and performing program programming, and the method is executed in the mcu circuit. The utility model only needs to connect the devices with corresponding functions through the connection relation given by the embodiment of the utility model, and does not relate to any improvement in program software. The connection mode between the hardware devices with the corresponding functions is realized by the prior art by those skilled in the art, and is not described in detail herein.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims

1. An oscilloscope port expansion control device for power supply ripple test is characterized by comprising a case, wherein a control circuit printed board is arranged in the case, and a switch matrix circuit, a first serial port circuit and a micro control unit circuit are packaged on the control circuit printed board;

2. The oscilloscope port expansion control device for the power supply ripple test according to claim 1, wherein the switch matrix circuit comprises a plurality of switch sub-circuits, each switch sub-circuit has the same structure and comprises an NPN-type triode and a normally open relay;

3. The oscilloscope port expansion control apparatus for power supply ripple test according to claim 2, wherein the switch sub-circuit further comprises a first resistor, a capacitor and a diode;

4. The oscilloscope port expansion control apparatus for power supply ripple test according to claim 2, wherein the switch sub-circuit further comprises a second resistor;

5. The oscilloscope port expansion control device for the power supply ripple test according to claim 1, wherein the first serial port circuit comprises a MAX485 chip, resistors R3-R7, R30, capacitors C16, C17, an inductor L3 and a PNP type triode Q1;

6. The oscilloscope port expansion control device for the power supply ripple test according to claim 1, wherein a second serial port circuit is further arranged on the control circuit printed board; the receiving end of the second serial port circuit is connected with the 3 rd pin of a second D-type data interface connector arranged on the case, the sending end is connected with the 2 nd pin of the second D-type data interface connector, the output end is connected with the second serial input end of the micro control unit circuit, and the input end is connected with the second serial output end of the micro control unit circuit.

7. The oscilloscope port expansion control device for the power supply ripple test according to claim 6, wherein the second serial port circuit comprises a MAX232 chip, capacitors C10-C15, an inductor L2;

8. The oscilloscope port expansion control device for the power supply ripple test according to claim 1, wherein a power supply circuit is further arranged on the control circuit printed board, and an input end of the power supply circuit is connected with a power supply input port arranged on the chassis and is used for being connected with a first power supply; the output end is used for providing a second power supply.

9. The oscilloscope port expansion control device for the power supply ripple test according to claim 8, wherein the power supply circuit comprises capacitors C1, C3-C5 and a voltage stabilization chip;

10. The oscilloscope port expansion control apparatus for power supply ripple test according to claim 9, wherein the power supply circuit further comprises a resistor R1;