CN115963745A - Simple signal power supply based on single chip microcomputer and PWM waveform obtaining method - Google Patents

Abstract

The invention discloses a simple signal power supply based on a single chip microcomputer and a PWM waveform obtaining method, which comprises the following steps: the device comprises an input module, a power supply module, a control module, an output module and a display module; the input module, the power supply module, the output module and the display module are respectively connected with the control module; the input module is used for receiving an externally input working instruction and transmitting the working instruction to the control module; the control module is used for receiving the control instruction sent by the input module and outputting a corresponding PWM waveform to the output module according to the control instruction; the output module is used for amplifying the PWM waveform and filtering harmonic frequency; outputting the PWM waveform to a display module; the power supply module is used for supplying power to the simple signal power supply; and the display module is used for displaying the functions of the control module. The problem of the demand for simple and reliable signal power supply under the present field condition is solved.

Description

Simple signal power supply based on single chip microcomputer and PWM waveform obtaining method

Technical Field

The invention relates to the technical field of power supplies, in particular to a simple signal power supply based on a single chip microcomputer and a PWM waveform obtaining method.

Background

Currently, the electric power signal measuring instrument generally adopts a method of 'periodic calibration + period check' to ensure the measuring accuracy. However, when some special condition measurements are performed, the measuring instrument is bumped through links such as splitting, packaging and transporting, and the use environment changes, and whether the measuring instrument which is reassembled is accurate in measurement on a test site or not is still lacking, and a method and a technical means for performing performance verification on equipment on the test site are still lacking.

For some devices (such as oscilloscopes), standard square signals with the frequency of 1kHz, the peak voltage of 5V and the duty ratio of 50 percent are used for verifying the performance of the oscilloscopes. Most power signal measurement devices do not have such standard signals on their own. It is also considered that, after the oscilloscope is split, packaged and transported, if the standard square wave signal of the oscilloscope is used for performance verification, if the measured signal parameter is inconsistent with the standard signal, the problem of the oscilloscope measurement loop or the problem of the standard signal output path cannot be determined. I.e. the reference signal output of the oscilloscope cannot meet the requirements.

Therefore, in power measurement, a simple and reliable signal power supply is urgently needed as a current (voltage) reference signal in the field for determining whether the measurement device is reliable. Compared with the laboratory conditions, the field verification method and the accuracy requirement of the equipment are relatively low, but the equipment is required to be simple in structure and convenient to carry, avoids the adoption of complex control, transmission and display methods, and is used for verifying the performance of the electric power signal measuring instrument under the field conditions.

Disclosure of Invention

In order to solve the above problems, the present invention provides a simple signal power supply based on a single chip, comprising: the device comprises an input module, a power supply module and a control module; the input module and the power supply module are respectively connected with the control module;

the input module is used for receiving an externally input working instruction and transmitting the working instruction to the control module;

the control module is used for receiving the working instruction sent by the input module and outputting a corresponding PWM waveform to the output module according to the working instruction;

the output module is used for amplifying the PWM waveform and filtering harmonic frequency; and outputting the PWM waveform.

Further, the method also comprises the following steps: the display device comprises a power supply module and a display module; the power supply module and the display module are respectively connected with the control module;

the power supply module is used for supplying power to the simple signal power supply;

and the display module is used for displaying the functions of the control module.

Further, the work order includes at least one of the following: an output command, a stop command, a change waveform command, a change frequency command, and a change duty cycle command.

Further, the input module includes: the device comprises a serial port input submodule, a USB input submodule, a WIFI input submodule and an infrared input submodule, wherein the submodules are used for receiving an externally input working instruction.

Further, the control module is specifically configured to:

if the current waveform outputs the selection square wave, the control module outputs a square wave signal with unchanged duty ratio to the output module according to the received duty ratio signal;

if the sine wave is selected for the current waveform output, outputting a PWM waveform with a duty ratio changing according to the sine to an output module;

and if the current waveform output selects the three-solution wave, outputting the PWM waveform with the duty ratio changing according to the three-solution function to an output module.

Furthermore, the control module adopts a single chip microcomputer as a core controller.

Further, the control module is further configured to: if the control module receives an output instruction, outputting the current waveform to an output module;

and if the control module receives a stop instruction, stopping outputting the current waveform to the output module.

Further, the output module includes: the switch submodule, the filter submodule and the resistance submodule are connected;

the switch submodule is used for amplifying the PWM waveform and is a double-input switch, and input signals are respectively the PWM waveform output by the 12V power supply of the power supply module and the PWM waveform output by the received control module; when the PWM waveform is at a high level, the switch is switched on, and the 12V power supply of the direct current power supply module is output to the filter module, otherwise, the switch is switched off;

the filter submodule is used for filtering the high-frequency switch harmonic frequency output by the switch submodule;

and the resistance submodule is used for converting the voltage signal output by the filter submodule into a current signal.

Furthermore, the power module outputs two different voltage power supplies, namely a 5V direct current power supply and a 12V direct current power supply, wherein the 5V direct current power supply is used for supplying power for the control module, and the 12V direct current power supply is used for supplying power for the switch sub-module of the output module.

The invention also provides a PWM waveform acquisition method based on the single chip microcomputer, which comprises the following steps:

receiving a working instruction sent by an input module;

outputting the corresponding PWM waveform to an output module according to the working instruction, wherein,

if the current waveform outputs the selection square wave, the control module outputs a square wave signal with unchanged duty ratio to the output module according to the received duty ratio signal;

if the sine wave is selected for the current waveform output, outputting a PWM waveform with a duty ratio changing according to the sine to an output module;

and if the current waveform output selects the three-solution wave, outputting the PWM waveform with the duty ratio changing according to the three-solution function to an output module.

According to the simple signal power supply based on the single chip microcomputer and the PWM waveform obtaining method, different types of waveforms such as triangular waves, square waves and sine waves can be generated, the frequency of the triangular waves, the frequency of the square waves and the frequency of the sine waves can be adjusted, the peak value of the square waves can be adjusted, and the duty ratio of the square waves can also be adjusted. Therefore, relatively accurate reference can be provided for various aspects such as peak value measurement, effective value measurement, period measurement, frequency measurement, duty ratio measurement, waveform measurement and the like of the power signal (voltage and current) measuring instrument under the field condition, and the field calibration requirement of the power signal measuring instrument is met. The problem of the demand for simple reliable signal power supply under the present field condition is solved.

Drawings

Fig. 1 is a block diagram of a hardware structure of a simple signal power supply based on a single chip microcomputer according to an embodiment of the present invention;

fig. 2 is an application example in which an STM32F103C8T6 type single chip microcomputer is used as a control module, an MAX232 chip is used as a serial port input module, and a CH340T chip is used as a USB input module according to an embodiment of the present invention;

fig. 3 is a diagram illustrating an example of a 12864 lcd display as a display module connected to a control module according to an embodiment of the present invention;

fig. 4 is an implementation example of the present invention, which uses a 9013 triode, a TLP521 optocoupler and an IKW20N60T IGBT as a switch module;

FIG. 5 is an embodiment of a UAF42 active filter chip selected to form a filter module according to the present invention;

FIG. 6 is a diagram of a DC power module according to the present invention, including a 5V lithium battery and a 12V lithium battery;

fig. 7 is a schematic flow chart of a PWM waveform obtaining method based on a single chip microcomputer according to the present invention.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather construed as limited to the embodiments set forth herein.

Example one

The invention provides a simple signal power supply based on a single chip microcomputer, the hardware structure diagram of which is shown in figure 1 and comprises: the device comprises an input module, a power supply module and a control module; the input module and the power supply module are respectively connected with the control module;

the input module is used for receiving an externally input working instruction and transmitting the working instruction to the control module;

the control module is used for receiving the working instruction sent by the input module and outputting a corresponding PWM waveform to the output module according to the working instruction;

the output module is used for amplifying the PWM waveform and filtering harmonic frequency; and outputting the PWM waveform.

Simple and easy signal power supply based on singlechip still includes: the display device comprises a power supply module and a display module; the power supply module and the display module are respectively connected with the control module;

the power supply module is used for supplying power to the simple signal power supply;

and the display module is used for displaying the functions of the control module. When the input module receives external instruction input and the control module adjusts the output of the next step according to the external instruction input, the received signal is output on the display module, so that a user can conveniently debug and confirm whether the debugging is finished.

The input module is used for receiving an externally input working instruction, and the working instruction comprises at least one of the following: an output command, a stop command, a change waveform command, a change frequency command, and a change duty cycle command.

The input module comprises a serial port input submodule, a USB input submodule, a WIFI input submodule and an infrared input submodule, and the submodules are used for receiving an externally input working instruction.

The control module is the core of the whole simple signal power supply and is used for receiving the control instruction sent by the input module, outputting a corresponding PWM waveform to the output module according to the control instruction, and if the current waveform outputs a selected square wave, outputting a square wave signal with unchanged duty ratio to the output module according to the received duty ratio signal; if the sine wave is selected for the current waveform output, outputting a PWM waveform with a duty ratio changing according to the sine to an output module; and if the current waveform output selects the three-solution wave, outputting the PWM waveform with the duty ratio changing according to the three-solution function to an output module. If the control module receives an output instruction, outputting the current waveform to an output module; and if the control module receives a stop instruction, stopping outputting the current waveform to the output module.

And the control module adopts a single chip microcomputer as a core controller.

The output module includes: the switch submodule, the filter submodule and the resistance submodule are connected;

the switch submodule is used for amplifying the PWM waveform and is a double-input switch, and input signals are respectively the PWM waveform output by the 12V power supply of the power supply module and the PWM waveform output by the received control module; when the PWM waveform is in a high level, the switch is switched on, and the 12V power supply of the direct current power supply module is output to the filter module, otherwise, the switch is switched off; therefore, the switching module actually plays a role in waveform amplification, and converts the PWM signal with low level of 0V, high level of 5V and small output current output by the controller into a PWM voltage signal with low level of 0V and high level of 12V and large current.

The filter submodule is used for filtering the high-frequency switch harmonic frequency output by the switch submodule; particularly, when outputting a "sine wave" or a "triangular wave", the switching module outputs a series of PWM waves whose duty ratio changes according to a sine or triangular rule, and good sine waves and triangular waves can be obtained only after filtering harmonics of the switching frequency through the filter module.

And the resistance submodule is used for converting the voltage signal output by the filter submodule into a current signal and providing a reference for the current signal measuring instrument.

The power module, the output includes two different voltage power supplies, is 5V DC power supply and 12V DC power supply respectively, and 5V DC power supply is used for doing control module power supply, 12V DC power supply is used for doing output module's switch submodule power supply.

Example two

The specific application examples are as follows:

in the following description, a detailed structure will be presented for a thorough understanding of embodiments of the invention. It is noted that the implementation of the embodiments of the invention is not limited to the specific details known to a person skilled in the art. The following detailed description of the preferred embodiments of the invention, however, the invention is capable of other embodiments in addition to those detailed.

Fig. 1 is a block diagram of a hardware configuration of a signal power supply provided by the present invention. The device comprises an input module, a direct current power supply module, a control module, a display module and an output module. The input module comprises a serial port input module, a USB input module, a WIFI input module and an infrared input module. The output module comprises a switch module, a filter module and a resistance module.

Fig. 2 is an application example of adopting an STM32F103C8T6 type single chip microcomputer as a control module, adopting a MAX232 chip as a serial port input module, and adopting a CH340T chip as a USB input module. The No. 2 and No. 3 pins of the 9-pin standard serial port are respectively connected with the No. 7 and No. 8 pins of the MAX232 chip. No. 16 and No. 15 pins of the MAX232 chip are respectively connected with a 5V power supply and a ground level, and No. 9 and No. 10 pins of the MAX232 chip are respectively connected with No. 13 and No. 12 pins of an STM32F103C8T6 single chip microcomputer. No. 1 and No. 4 pins of the 4-pin standard USB interface are respectively connected with a 5V power supply and a ground level, and No. 2 and No. 3 pins are respectively connected with No. 7 and No. 6 pins of a CH340T chip. No. 19 and No. 8 pins of the CH340T chip are respectively connected with a 5V power supply and a ground level, and No. 3 and No. 4 pins are respectively connected with No. 21 and No. 22 pins of an STM32F103C8T6 single chip microcomputer. Pin 29 of the STM32F103C8T6 singlechip is a general output A8 port, and therefore is labeled as PA8, which is also PA8 in fig. 4. The pin is a singlechip PWM output pin and is used for outputting PWM waveforms to an output module.

The serial port input module and the USB input module are used for receiving control instructions of an upper computer (such as a personal computer). The control instructions are represented by a 2 byte (16 bit) code as shown in the following table:

TABLE 1 instruction code Table

Note 1: the 16-bit instructions range from 0000H to FFFFH for a total of 65535. Except as listed in this table, the rest are invalid instructions.

Note 2: in this table.

H in the above table represents hexadecimal. The 16bit data corresponding to 1010H is 0001 0000 0001 0000. The 16bit data corresponding to 13FFH is 0001 0011 1111 1111.

A complete workflow is as follows: in the initial state, the signal power supply does not output. And when the serial port receiving module receives a 1202H instruction and a 1304H instruction transmitted by the upper computer, the output waveform is selected to be triangular wave, and the frequency is selected to be 50Hz. And after receiving 1010H instruction transmitted by the upper computer, outputting triangular wave with the frequency of 50Hz at the PA8 port immediately. And when receiving a 1100H instruction transmitted by the upper computer, the PA8 port of the singlechip stops outputting. And after receiving the 1201H instruction and the 1309H instruction transmitted by the upper computer again, selecting the output waveform as a sine wave and selecting the frequency as 100Hz. After receiving a 1010H instruction transmitted by the upper computer, the sine wave with the frequency of 100Hz is immediately output at the PA8 port. And when the 1100H instruction transmitted by the upper computer is received, the output of the PA8 port of the singlechip is stopped.

It should be noted that the functions of the USB input module, the WIFI input module, the infrared input module, and the like are consistent with the functions of the serial port input module. And will not be described in detail herein. In addition, the STM32F103C8T6 single chip microcomputer and the CH340T and MAX232 chips all need necessary components such as a crystal oscillator, a resistor, a capacitor and the like to work normally, but the components are not shown in fig. 2.

Fig. 3 shows an example of a display module using a 12864 liquid crystal panel. The display module is mainly used for displaying the current working state. 12864 means that the liquid crystal panel has 128 pixels in the transverse direction and 64 pixels in the longitudinal direction. The general Chinese characters are 16 pixels in the horizontal direction and the longitudinal direction, and the general English letters and Arabic letters are 8 pixels in the horizontal direction and 16 pixels in the longitudinal direction, so that the 12864 liquid crystal display can display 4 rows and 8 columns of Chinese characters or 4 rows and 16 columns of English. Enough to display the information of the simple power supply. For example, after the serial port receiving module receives 1202H instructions, 1304H instructions and 1010H transmitted by the upper computer, the single chip microcomputer outputs triangular waves with the frequency of 50Hz at the port PA8, and at the moment, "triangular waves", "frequency 50Hz" and "working" are displayed on the liquid crystal screen. When an 1100H instruction transmitted by the upper computer is received, the output of the port PA8 of the singlechip is stopped, and the triangular wave, the frequency 50Hz and the stop are displayed on the liquid crystal screen.

Fig. 4 is an embodiment example of a switch module. Comprising a resistor R ₁ 、R ₂ And R ₃ A capacitor C, a triode, an optical coupler and an insulated gate bipolar transistor IGBT. The triode is a 9013 type triode, the optocoupler is TLP521, and the IGBT is IKW20N60T. Collector and resistor R of the triode ₁ Is connected to the base and the resistor R ₂ One end of the optical coupler is connected, and the emitting electrode is connected with the input end of the optical coupler; resistance R ₁ The other end of the power supply is connected with a +5V power supply; resistance R ₂ The other end of the main controller module is connected with the main controller module; the other end of the optical coupler is grounded; an output end of the optical coupler is respectively connected with the resistors R ₃ One end of the capacitor C is connected with a gate pole of the IGBT, and the other output end of the capacitor C is respectively connected with one end of the capacitor C and the groundConnecting; the resistance R ₃ The other end of the capacitor C is respectively connected with the other end of the capacitor C and a +12V power supply. The IGBT emitter is connected with the No. 2 terminal, the ground and the negative electrode of a 12V power supply, the collector is connected with the No. 1 terminal and a resistor R ₄ Are connected to one end of R ₄ The other end of the switch is connected with the positive pole of a 12V power supply. 5V and 12V power supplies are power supplies included in the DC power supply module.

In the initial state, the PA8 port of the singlechip is at low level. At this time, the base potential of the transistor 9013 is low, and 9013 is cut off. The optocoupler TLP521 is internally dark and is in an off state, a gate signal of the IGBT is pulled high by a 12V power supply, the IGBT is switched on, the No. 1 terminal is grounded, and no voltage exists between the No. 1 terminal and the No. 2 terminal.

After receiving the 'start' instruction, the PA8 port of the singlechip outputs PWM waves. As described above, when the PA8 port is at a low level, the voltage is 0 at the No. 1 and No. 2 terminals. And when the port of the PA8 is in a high level, 9013 is conducted. The optocoupler TLP521 has light inside and is in an on state, a gate signal of the IGBT is pulled down, the IGBT is turned off, the No. 1 terminal is pulled up to 12V by a 12V power supply, and the voltage of the No. 1 and No. 2 terminals is 12V at the moment.

The single chip microcomputer outputs a series of PWM waveforms with duty ratios changing regularly, and the PWM waveforms with the peak values of 12V and the duty ratios changing regularly are obtained on the No. 1 terminal and the No. 2 terminal. After passing through the filter module, the required sine wave or triangular wave is obtained.

If the current needs to be measured, the current of the resistor R4 can be directly measured.

Fig. 5 is an embodiment of a filter module formed by selecting UAF42 chips. Comprises a UAF42 active filter chip and a resistor R _Q 、R _2A 、R _F1 、R _F2 、R _Z1 、R _Z2 、R _Z3 And a capacitor C _1A 、C _2A . No. 3 pin and resistor R of UAF42 chip _Q Are connected to one end of R _Q And the other end of the same is grounded. No. 12 and No. 13 pins and resistor R of UAF42 chip _2A Are connected with the two ends of the resistor R, and the No. 13 and No. 8 pins are connected with the resistor R _F1 Are connected with the two ends of the capacitor C, and the No. 8 and No. 7 pins are connected with the capacitor C _1A Are connected with the two ends of the resistor R, and pins No. 7 and No. 14 are connected with the resistor R _F2 Are connected, 14 and No. 1 pins are connected with a capacitor C _2A Connected, pin No. 1 and 5 and resistor R _Z1 Are connected with the two ends of the resistor R, and the No. 5 and No. 6 pins are connected with the resistor R _Z3 Connected with No. 5 and No. 13 pins and a resistor R _Z2 Are connected at both ends. Pin No. 2 is connected to the input signal and pin No. 6 is connected to the output signal. By appropriate selection of R _F1 、R _F2 And R _G Can form a band-stop filter (also called a wave trap) for 8 kHz.

Preferably, R _F1 、R _F2 And R _G The adjustable resistor can be adopted, so that parameters such as pass band cut-off frequency, stop band gain and the like of the band-stop filter can be adjusted, and the influence of fixed resistance parameter deviation on the filtering performance is avoided.

Fig. 6 is an embodiment of a dc power module, which includes a 5V dc power supply and a 12V dc power supply, both of which are polymer lithium batteries.

EXAMPLE III

Based on the same inventive concept, the invention also provides a PWM waveform obtaining method based on the singlechip, as shown in FIG. 7, comprising the following steps:

step S201, receiving a working instruction sent by an input module;

step S202, outputting the corresponding PWM waveform to an output module according to the working instruction, wherein,

if the current waveform outputs the selected square wave, the control module outputs the square wave signal with unchanged duty ratio to the output module according to the received duty ratio signal;

if the sine wave is selected for the current waveform output, outputting a PWM waveform with a duty ratio changing according to the sine to an output module;

and if the current waveform output selects the three-solution wave, outputting the PWM waveform with the duty ratio changing according to the three-solution function to an output module.

The work instruction sent by the output module comprises at least one of the following: an output command, a stop command, a change waveform command, a change frequency command, and a change duty cycle command.

The switch submodule is used for amplifying the PWM waveform and is a double-input switch, and input signals are respectively the PWM waveform output by the 12V power supply of the power supply module and the PWM waveform output by the received control module; when the PWM waveform is in a high level, the switch is switched on, and the 12V power supply of the direct current power supply module is output to the filter module, otherwise, the switch is switched off;

the filter submodule is used for filtering the high-frequency switch harmonic frequency output by the switch submodule;

and the resistance submodule is used for converting the voltage signal output by the filter submodule into a current signal and providing a reference for the current signal measuring instrument.

The invention provides a simple signal power supply based on a single chip microcomputer. The invention can generate different types of waveforms such as triangular waves, square waves, sine waves and the like, and the frequency, the peak value and the duty ratio of the square waves can be adjusted. Therefore, relatively accurate reference can be provided for various aspects such as peak value measurement, effective value measurement, period measurement, frequency measurement, duty ratio measurement, waveform measurement and the like of the power signal (voltage and current) measuring instrument under the field condition, and the field calibration requirement of the power signal measuring instrument is met. Meanwhile, the simple signal power supply is simple in structure, light in weight, capable of being packaged into a whole, convenient to carry and very suitable for field calibration and evaluation of the power signal measuring instrument. The problem of the demand for simple and reliable signal power supply under the present field condition is solved.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention.

Claims (10)

1. The utility model provides a simple and easy signal power supply based on singlechip which characterized in that includes: the device comprises an input module, a power supply module and a control module; the input module and the power supply module are respectively connected with the control module;

the input module is used for receiving an externally input working instruction and transmitting the working instruction to the control module;

the control module is used for receiving the working instruction sent by the input module and outputting a corresponding PWM waveform to the output module according to the working instruction;

the output module is used for amplifying the PWM waveform and filtering harmonic frequency; and outputting the PWM waveform.

2. The simple signal power supply of claim 1, further comprising: the display device comprises a power supply module and a display module; the power supply module and the display module are respectively connected with the control module;

the power supply module is used for supplying power to the simple signal power supply;

and the display module is used for displaying the functions of the control module.

3. The simple signal power supply of claim 1, wherein the operating instructions comprise at least one of: an output command, a stop command, a change waveform command, a change frequency command, and a change duty cycle command.

4. The simple signal power supply of claim 1, wherein the input module comprises: the device comprises a serial port input submodule, a USB input submodule, a WIFI input submodule and an infrared input submodule, wherein the submodules are used for receiving an externally input working instruction.

5. The simple signal power supply of claim 1, wherein the control module is specifically configured to:

if the current waveform outputs the selection square wave, the control module outputs a square wave signal with unchanged duty ratio to the output module according to the received duty ratio signal;

if the sine wave is selected for the current waveform output, outputting a PWM waveform with a duty ratio changing according to the sine to an output module;

and if the current waveform output selects the three-solution wave, outputting the PWM waveform with the duty ratio changing according to the three-solution function to an output module.

6. The simple signal power supply of claim 1, wherein the control module uses a single chip as a core controller.

7. The simple signal power supply of claim 1, wherein the control module is further configured to: if the control module receives an output instruction, outputting the current waveform to an output module;

and if the control module receives a stop instruction, stopping outputting the current waveform to the output module.

8. The simple signal power supply of claim 1, wherein the output module comprises: the switch submodule, the filter submodule and the resistance submodule are connected;

the switch submodule is used for amplifying the PWM waveform to form a double-input switch, and input signals are respectively the PWM waveform output by a 12V power supply of the power supply module and the PWM waveform output by the received control module; when the PWM waveform is at a high level, the switch is switched on, and the 12V power supply of the direct current power supply module is output to the filter module, otherwise, the switch is switched off;

the filter submodule is used for filtering the high-frequency switch harmonic frequency output by the switch submodule;

and the resistance submodule is used for converting the voltage signal output by the filter submodule into a current signal.

9. The simple signal power supply of claim 1, wherein the power supply module comprises two different voltage power supplies, namely a 5V dc power supply and a 12V dc power supply, wherein the 5V dc power supply is used for supplying power to the control module, and the 12V dc power supply is used for supplying power to the switch sub-module of the output module.

10. A PWM waveform obtaining method based on a single chip microcomputer is characterized by comprising the following steps:

receiving a working instruction sent by an input module;

outputting the corresponding PWM waveform to an output module according to the working instruction, wherein,

if the current waveform outputs the selected square wave, the control module outputs the square wave signal with unchanged duty ratio to the output module according to the received duty ratio signal;

if the sine wave is selected for the current waveform output, outputting a PWM waveform with a duty ratio changing according to the sine to an output module;

and if the current waveform output selects the three-solution wave, outputting the PWM waveform with the duty ratio changing according to the three-solution function to an output module.

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