Handheld low-power-consumption small alternating current constant current source

Abstract

The handheld low-power-consumption small alternating current constant current source comprises a power supply control module, an SPWM driving feedback module, a man-machine interaction module and an external mutual inductor test module, can generate 0-1A alternating current, has the overall power consumption within 50mW, can be powered by two No.5 dry batteries, can also be externally connected with a 5V power supply through a TYPE-C interface, and can be used for testing the power consumption of the power supply. One single-chip microcomputer is used for completing the functions of SPWM waveform calculation, current constant current feedback, mutual inductor parameter measurement, key pressing, display and the like.

Description

Technical Field

[0001] The present application relates to the field of electrical measurement technology, and in particular to a handheld low-power small AC constant current source. Background Art

[0002] The AC constant current source used in the traditional calibration table has a large power consumption of hundreds of watts. The control, calculation, current sampling and display of the traditional AC constant current source use multiple chips. The total power consumption of the chip itself exceeds 100mW. It needs to be powered by an AC power supply and cannot be powered by dry batteries or other power sources. Traditional AC constant current sources often use large magnetic cores, large size, heavy weight, and dozens of kilograms of weight cannot be portable, and often need to be transported by a cart.

[0003] Therefore, the present application provides a handheld low-power small AC constant current source to solve the above technical problems. Summary of the invention

[0004] In view of the problems in the prior art, the present application provides a handheld low-power small AC constant current source.

[0005] In a first aspect, the present invention provides a handheld low-power small AC constant current source, comprising:

[0006] Power supply control module, SPWM drive feedback module, human-computer interaction module and external transformer test module;

[0007] The power control module is electrically connected to the human-computer interaction module; the human-computer interaction module is electrically connected to the SPWM drive feedback module; the SPWM drive feedback module is electrically connected to the external transformer test module;

[0008] The power control module supplies power to the SPWM drive feedback module, the human-computer interaction module and the external transformer test module, and outputs a control signal to the SPWM drive feedback module and the external transformer test module; after receiving the control signal, the SPWM drive feedback module calculates the SPWM waveform and adjusts the current line current to a set constant current value; the external transformer test module samples and analyzes the external current; the human-computer interaction module collects the SPWM waveform, the constant current value and the external current sampling and analysis results and outputs an image.

[0009] Preferably, the power control module includes:

[0010] A first power supply module, wherein the first power supply module comprises at least one battery box;

[0011] The second power supply module comprises at least one TYPE-C interface.

[0012] Furthermore, the first power supply module includes:

[0013] A first cascade power supply interface and a second cascade power supply interface, wherein the first cascade power supply interface and the second cascade power supply interface are connected in parallel with the battery box.

[0014] Preferably, the human-computer interaction module includes:

[0015] Display module, used to display SPWM waveform constant current value and external current sampling analysis results;

[0016] An instruction module, used for sending a start / stop signal to the power control module;

[0017] The sound module outputs a corresponding prompt sound according to the start / stop signal sent by the instruction module.

[0018] Preferably, the SPWM drive feedback module includes:

[0019] A first gate circuit chip, a second gate circuit chip, a first N+P combination MOS tube, a second N+P combination MOS tube, a first filtering and rectifying circuit, a second filtering and rectifying circuit, a mutual inductor, a feedback mutual inductor and a current line;

[0020] The output end of the first gate circuit chip is connected to the input end of the first N+P combination MOS tube, the output end of the first N+P combination MOS tube is connected to the input end of the first filter rectifier circuit, the output end of the first filter rectifier circuit is connected to the input end of the mutual inductor, and the output end of the mutual inductor is connected to the current line;

[0021] The output end of the second gate circuit chip is connected to the input end of the second N+P combination MOS tube, the output end of the second N+P combination MOS tube is connected to the input end of the second filtering and rectifying circuit, the output end of the second filtering and rectifying circuit is connected to the input end of the mutual inductor, and the output end of the mutual inductor is connected to the current line.

[0022] The current line is connected to the input end of the feedback transformer, and the output end of the feedback transformer serves as the output end of the SPWM drive feedback module.

[0023] Preferably, the external transformer testing module comprises:

[0024] An external transformer, a relay, a DC bias circuit, a bias reference voltage, a first NMOS tube and a single-chip microcomputer; the input end of the external transformer is connected to the output end of the relay, the input end of the DC bias circuit is connected to the output end of the relay, the bias reference voltage output end is connected to the input end of the relay, the gate of the first NMOS tube is connected to an external control signal, the source of the first NMOS tube is grounded, and the drain of the first NMOS tube is connected to the third input end of the relay; the output end of the external transformer is connected to the input end of the single-chip microcomputer, and the output end of the DC bias circuit is connected to the input end of the single-chip microcomputer.

[0025] It can be seen from the above technical solution that the handheld low-power small AC constant current source provided by the present application can generate 0-1A AC power, and the overall power consumption is within 50mW. It can be powered by 2 No. 5 dry batteries, or by an external 5V power supply through the TYPE-C interface. It uses a single-chip microcomputer to complete SPWM waveform calculation, current constant current feedback, transformer parameter measurement, buttons and display and other functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 It is an overall diagram of a handheld low-power small AC constant current source in an embodiment of the present application;

[0028] Figure 2 This is a diagram of a power control module in an embodiment of the present application;

[0029] Figure 3 This is a diagram of the SPWM drive feedback module in the embodiment of the present application;

[0030] Figure 4 It is a diagram of a human-computer interaction module in an embodiment of the present application;

[0031] Figure 5 This is a diagram of an external transformer test module in an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] The present application provides a handheld low-power small AC constant current source, the overall power consumption is within 50mW, and can generate 0-1A AC. The present invention can be powered by 2 No. 5 dry batteries, or by an external 5V power supply through a TYPE-C interface. The overall weight of the present invention is only 200g, and the volume is 10.5cm*4.5cm*3.5cm, which is suitable for carrying. One single-chip microcomputer is used to complete SPWM waveform calculation, current constant current feedback, mutual inductor parameter measurement, buttons and display and other functions. The overall power consumption is effectively controlled, making it possible to use 2 No. 5 dry batteries for power supply.

[0034] The details are described through the following multiple embodiments and application examples.

[0035] The present application provides a handheld low-power small AC constant current source, such as Figure 1 As shown, including:

[0036] Power supply control module, SPWM drive feedback module, human-computer interaction module and external transformer test module;

[0037] The power control module is electrically connected to the human-machine interaction module; the human-machine interaction module is electrically connected to the SPWM drive feedback module; the SPWM drive feedback module is electrically connected to the external transformer test module;

[0038] The power control module supplies power to the SPWM drive feedback module, the human-computer interaction module and the external transformer test module, and outputs control signals to the SPWM drive feedback module and the external transformer test module; after receiving the control signal, the SPWM drive feedback module calculates the SPWM waveform and adjusts the current line current to the set constant current value; the external transformer test module samples and analyzes the external current; the human-computer interaction module collects the SPWM waveform, constant current value and external current sampling and analysis results and outputs an image.

[0039] like Figure 2As shown, in the embodiment of the present application, the power control module is composed of a No. 5 battery box B1, a TYEP-C interface J5, a 2-core cascade power supply port J9, J10, and a low-power switch control. After two No. 5 batteries are loaded into the No. 5 battery box, the switch circuit defaults to the off state, and the G pole P_G of the two PMOS tubes Q8 and Q4 connected in series back to back is pulled up to VBAT by R8, Q8 and Q4 are turned off, and the battery circuit consumes 0 current. When the power button KEY_A is pressed, the 2nd pin of the diode D8 is pulled down to a lower level, and this level pulls down the P_G signal through R30, so that Q8 and Q4 are turned on, and the single-chip microcomputer obtains the MVDD voltage. After the single-chip microcomputer obtains the MVDD voltage, it immediately initializes IO: PWR_ON to output a high level, and the NMOS tube Q6 is turned on, replacing KEY_A to pull P_G down through R30, so that Q8 and Q4 are always turned on, and finally completes the entire power-on work. When the system is shut down, PWR_ON outputs a low level, causing P_G to be pulled up by R8, Q8 and Q4 to be turned off, and the shutdown action is completed. When using TYPE-C for power supply, the +5V voltage supplies power to MVDD through Schottky diode D6, and the microcontroller knows to use TYEP-C by judging the MVDD voltage range. The +5V voltage raises the P_G voltage to about 4.7V through D11, which is higher than the 3V voltage of VBAT. At this time, Q8 and Q4 are always cut off, and the power supply of VBAT is turned off. At the same time, MVDD is prevented from reversely charging VBAT through Q8 and Q4, preventing the risk of battery leakage. When using 5V power supply, multiple small AC constant current sources can be easily connected in parallel through 2-core cables through J9 and J10. When using dry batteries for power supply, other small AC constant current sources will not be powered through this 2-core cable, which prevents the battery from being quickly consumed by large currents.

[0040] As a preferred embodiment, the power supply mode designed by the present invention can not only use 2 No. 5 dry batteries for power supply, but also input 5V power supply through the TYPE-C interface. When conditions permit, use a charging head, power bank, etc. to provide 5V power supply instead of dry batteries to reduce disposable battery consumption and be more environmentally friendly. When there are multiple small AC constant current sources working, except for the first one powered by TYPC-C, other small AC constant current sources can be powered by a 2-core cascade power supply line, without the need for multiple charging heads. Flexible and diverse power supply methods can meet the application of various use scenarios such as research and development, production, and field testing, unlike the traditional AC constant current source that can only use 220V power supply.

[0041] like Figure 3 As shown, in the embodiment of the present application, the SPWM drive feedback module is composed of gate circuit chips U2, U3 for enhancing the driving capability of the IO port of the single-chip microcomputer, N+P combination MOS tubes Q1, Q5 with small volume and low junction capacitance, a filter circuit, a mutual inductor T1, a feedback mutual inductor T2, and a current line.

[0042] The complementary SPWM signals TIM5_CHA and TIM5_CHB with dead zone generated by the single-chip microcomputer are driven and enhanced through U2 and U3, and the signal is reversed through U3. In this way, two SPWM signals are used to replace the original four MOSs that need four SPWM signals to drive the H bridge. A low-power H bridge composed of Q1 and Q5 is used to generate a power-type SPWM signal. The power-type SPWM signal obtains an AC signal through two LC filters composed of L1, C6, L2, and C12. The AC signal is used to block DC and pass AC through C30 to further remove the DC component. After the AC signal is input to the left coil of the transformer T1, it is induced to the current line on the right. Because the current line has a low internal resistance, a large current flows inside after a short circuit. Connect the transformer T2 to the current line, and the secondary side of T2 senses the current and generates a feedback signal FB_CT through R20. FB_CT generates a CT2_SIG signal through the voltage bias circuit composed of R22, R9, and R12 to the ADC of the single-chip microcomputer for processing. The microcontroller calculates the current of the current line according to the CT2_SIG signal, adjusts the duty cycle of the SPWM in real time, and adjusts the current of the current line to the set constant current value.

[0043] like Figure 4 As shown, in the embodiment of the present application, the human-computer interaction module is composed of an OLED display, a button, and a buzzer. The use of a small 128X64 OLED display has lower power consumption than a color screen, with a display power consumption of only 10mW, and can display any waveform compared to a segment LCD screen. The OLED screen can be used to display the startup waveform and output AC signal waveform of the passive wireless power sensor: standard sine wave output and arbitrary signal output mode waveform display. OLED uses a separate LDO chip U6 to obtain a stable OLED_VCC voltage, and whether it uses 2 No. 5 batteries or 5V power supply will not cause the OLED voltage to be too high. The button KEY_A realizes the power on / off function and button function reuse through the cooperation of diode D8. KEY_A and KEY_B realize various functions such as setting current size, output waveform, function selection, etc. through the cooperation of long press and short press. The button improves the anti-interference ability by connecting parallel filter capacitors C4 and C9. The passive buzzer BEEP1 is connected to the TIM output interface of the microcontroller through R24. The microcontroller can output a variety of prompt sounds by changing the frequency and duty cycle of the timer, which can prompt buttons and various test results. After pressing the button to start the test, you can judge whether the test has passed by listening to the sound, which greatly increases the efficiency of human-computer interaction.

[0044] like Figure 5As shown, in the embodiment of the present application, the external transformer test module is composed of an external transformer interface J4, a switching relay control, a DC bias circuit and a bias reference voltage. When the passive wireless power sensor is to be tested and started, SW_RE outputs a low level, the relay coil has no voltage and does not operate, the external transformer CT2_A signal is not connected to the circuit to consume energy, and its own energy is used for the startup test of the passive wireless power sensor. When SW_RE outputs a high level, Q2 is turned on, K2 is energized, and the CT2_A signal generates an AC voltage signal through R10. The AC voltage signal generates a DC signal CT1_SIG that varies between 0-1.5V through the DC bias circuit of R31, R32, and R16 and enters the ordinary ADC of the microcontroller for sampling. The microcontroller compares the amplitude and phase of the two signals CT1_SIG and CT2_SIG, and can calculate the same-name terminals, number of turns, angle difference and other parameters of the passive wireless power sensor. The MVDD voltage obtains a 1.5V reference voltage through U1, which is used to power the DC bias circuit and the reference voltage of the microcontroller ADC.

[0045] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (apparatus), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0046] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0047] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0048] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A handheld low-power small AC constant current source, characterized in that: include: Power supply control module, SPWM drive feedback module, human-computer interaction module and external transformer test module; The power control module is electrically connected to the human-computer interaction module; the human-computer interaction module is electrically connected to the SPWM drive feedback module; the SPWM drive feedback module is electrically connected to the external transformer test module; The power control module supplies power to the SPWM drive feedback module, the human-computer interaction module and the external transformer test module, and outputs a control signal to the SPWM drive feedback module and the external transformer test module; after receiving the control signal, the SPWM drive feedback module calculates the SPWM waveform and adjusts the current line current to a set constant current value; the external transformer test module samples and analyzes the external current; the human-computer interaction module collects the SPWM waveform, the constant current value and the external current sampling and analysis results and outputs an image.

2. The handheld low-power small AC constant current source according to claim 1 is characterized in that: The power control module comprises: A first power supply module, wherein the first power supply module comprises at least one battery box; The second power supply module comprises at least one TYPE-C interface.

3. The handheld low-power small AC constant current source according to claim 2 is characterized in that: The first power supply module comprises: A first cascade power supply interface and a second cascade power supply interface, wherein the first cascade power supply interface and the second cascade power supply interface are connected in parallel with the battery box.

4. The handheld low-power small AC constant current source according to claim 1 is characterized in that: The human-computer interaction module comprises: Display module, used to display SPWM waveform constant current value and external current sampling analysis results; An instruction module, used for sending a start / stop signal to the power control module; The sound module outputs a corresponding prompt sound according to the start / stop signal sent by the instruction module.

5. The handheld low-power small AC constant current source according to claim 1 is characterized in that: The SPWM drive feedback module includes: A first gate circuit chip, a second gate circuit chip, a first N+P combination MOS tube, a second N+P combination MOS tube, a first filtering and rectifying circuit, a second filtering and rectifying circuit, a mutual inductor, a feedback mutual inductor and a current line; The output end of the first gate circuit chip is connected to the input end of the first N+P combination MOS tube, the output end of the first N+P combination MOS tube is connected to the input end of the first filter rectifier circuit, the output end of the first filter rectifier circuit is connected to the input end of the mutual inductor, and the output end of the mutual inductor is connected to the current line; The output end of the second gate circuit chip is connected to the input end of the second N+P combination MOS tube, the output end of the second N+P combination MOS tube is connected to the input end of the second filtering and rectifying circuit, the output end of the second filtering and rectifying circuit is connected to the input end of the mutual inductor, and the output end of the mutual inductor is connected to the current line; The current line is connected to the input end of the feedback transformer, and the output end of the feedback transformer serves as the output end of the SPWM drive feedback module.

6. The handheld low-power small AC constant current source according to claim 1, characterized in that: The external transformer test module comprises: An external transformer, a relay, a DC bias circuit, a bias reference voltage, a first NMOS tube and a single-chip microcomputer; the input end of the external transformer is connected to the output end of the relay, the input end of the DC bias circuit is connected to the output end of the relay, the bias reference voltage output end is connected to the input end of the relay, the gate of the first NMOS tube is connected to an external control signal, the source of the first NMOS tube is grounded, and the drain of the first NMOS tube is connected to the third input end of the relay; the output end of the external transformer is connected to the input end of the single-chip microcomputer, and the output end of the DC bias circuit is connected to the input end of the single-chip microcomputer.

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