CN203745941U - DC current source circuit based on closed-loop control of PWM (Pulse-Width Modulation) technology - Google Patents
DC current source circuit based on closed-loop control of PWM (Pulse-Width Modulation) technology Download PDFInfo
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- CN203745941U CN203745941U CN201320763799.0U CN201320763799U CN203745941U CN 203745941 U CN203745941 U CN 203745941U CN 201320763799 U CN201320763799 U CN 201320763799U CN 203745941 U CN203745941 U CN 203745941U
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Abstract
The utility model discloses a DC current source circuit based on closed-loop control of PWM (Pulse-Width Modulation) technology. The DC current source circuit comprises a forward current generating module and a feedback loop module, wherein the forward current generating module is connected to a PWM output port of a microprocessor, and is used for converting pulse width modulation signals generated by the PWM output port into direct current in proportion to pulse width; the feedback loop module is connected to the output end of the forward current generating module and used for collecting the output current of the forward current generating module, and then carrying out treatment so as to convert the output current into digital voltage signals to send to a microprocessor. According to the utility model, the PWM technology is adopted for outputting voltage, hardware cost is reduced, the circuit is simplified, moreover, a closed-loop control principle is adopted, feedback collection to the output current is performed and the output current is converted into digital signals, the microprocessor can calculate output errors through recovery to the output signals, then compensation is performed automatically for outputting again, the outputting accuracy is higher than that of a traditional output circuit, and manual intervention is not required.
Description
Technical field
The utility model, about a kind of DC current source circuit, particularly relates to a kind of DC current source technology based on the closed-loop control of PWM technology.
Background technology
Existing 4～20mA output circuit, mostly is voltage-controlled current source output circuit, when with microcontroller interface, must adopt DA output conversion element, and digital signal output is converted to simulating signal, controls the size of DC current output.
Fig. 1 is 4-20mA output circuit and microcontroller interface circuit block diagram in prior art.Wherein voltage-controlled type 4-20mA output module comprises low-pass filter, buffer circuit, Voltage-controlled Current Source output protection circuit; interface between this voltage-controlled type 4-20mA output module and microprocessor adopts DA pio chip; DA pio chip is by the voltage digital signal of needs output; through DA chip (analog-digital chip), digital voltage signal is converted to after analog voltage signal, convert DC current signal to through 4-20mA change-over circuit and transport to load.
But, there is following shortcoming in the output DC current 4-20mA output that above employing is traditional: 1, microprocessor must convert digital signal to analog voltage signal, need to increase DA conversion chip, has increased hardware investment and design complexity.2, measure and control because output current error cannot realize, cause the error of output current larger, and regulation output error automatically, necessary manual shift circuit parameter.
Utility model content
The deficiency existing for overcoming above-mentioned prior art, the object of the utility model is to provide a kind of DC current source circuit based on the closed-loop control of PWM technology, by adopting PWM pulse modulation technology, voltage is exported, avoid employing DA pio chip to control, save hardware cost, and simplify circuit, adopted loop control theory simultaneously, output current is carried out to feedback collection, and convert digital signal to, microprocessor calculates output error by the back production to output signal, then automatically compensate output again, output accuracy is higher than traditional output circuit, and do not need manual intervention.
For reaching above-mentioned and other object, the utility model proposes a kind of DC current source circuit based on the closed-loop control of PWM technology, at least comprise:
Forward current generation module, is connected in the PWM output port of microprocessor, and the pulse width modulated signal conversion that PWM output port is produced is direct current proportional to pulsewidth;
Backfeed loop module, is connected in the output terminal of described forward current generation module, converts digital voltage signal to and is sent to microprocessor processing after the output current collection of described forward current generation module.
Further; described forward current generation module comprises input low-pass filter, following by inputting voltages device, linear optical coupling buffer circuit, Voltage-controlled Current Source, output protection circuit; the PWM output port of microprocessor described in described input low-pass filter input termination, described input low-pass filter, described following by inputting voltages device, described linear optical coupling buffer circuit, described Voltage-controlled Current Source, the cascade successively of described output protection circuit.
Further; described backfeed loop module comprises output current Acquisition Circuit, feedback voltage follower, feedback voltage low-pass filter and analog to digital converter; described current collection circuit is connected in the cold junction of described output protection circuit; to converting voltage to after output current collection; and after described feedback voltage follower and the filtering of described feedback voltage low-pass filter; be input to described analog to digital converter and carry out analog to digital conversion, analog to digital conversion result is sent to described microprocessor by data bus.
Compared with prior art, visible, a kind of DC current source based on the closed-loop control of PWM technology of the utility model is by adopting PWM pulse modulation technology to export voltage, avoid employing DA pio chip to control, save hardware cost, and simplify circuit, adopted loop control theory simultaneously, output current is carried out to feedback collection, and converting digital signal to, microprocessor calculates output error by the back production to output signal, then automatically compensates output again, output accuracy is higher than traditional output circuit, and does not need manual intervention.
Brief description of the drawings
Fig. 1 is 4-20mA output circuit and microcontroller interface circuit block diagram in prior art;
Fig. 2 is the schematic block circuit diagram of a kind of DC current source circuit based on the closed-loop control of PWM technology of the utility model;
Fig. 3 is the circuit structure diagram of the utility model preferred embodiment.
Embodiment
Below, by specific instantiation accompanying drawings embodiment of the present utility model, those skilled in the art can understand other advantage of the present utility model and effect easily by content disclosed in the present specification.The utility model also can be implemented or be applied by other different instantiation, and the every details in this instructions also can be based on different viewpoints and application, carries out various modifications and change not deviating under spirit of the present utility model.
Fig. 2 is the schematic block circuit diagram of a kind of DC current source circuit based on the closed-loop control of PWM technology of the utility model.As shown in Figure 2; a kind of DC current source circuit based on the closed-loop control of PWM technology of the utility model, comprising: input low-pass filter 201, following by inputting voltages device 202, linear optical coupling buffer circuit 203, Voltage-controlled Current Source 204, output protection circuit 205 and backfeed loop module 206.
Wherein input the PWM output port of the input termination microprocessor of low-pass filter 201; input low-pass filter 201, following by inputting voltages device 202, linear optical coupling buffer circuit 203, Voltage-controlled Current Source 204, output protection circuit 205 cascade successively; form forward current generation module; backfeed loop module 206 is connected to the output terminal of output protection circuit 205; convert digital voltage signal to and be sent to microprocessor and export and regulate to reduce error processing after the output current collection of output protection circuit, improve output current precision.
In the utility model preferred embodiment, backfeed loop module 206 comprises output current Acquisition Circuit 207, feedback voltage follower 208, feedback voltage low-pass filter 209 and analog to digital converter (ADC) 210.Current collection circuit 207 is connected in the cold junction of output protection circuit 205; after the cold junction of output circuit gathers output current; convert voltage to; and after feedback voltage follower 208 and 209 filtering of feedback voltage low-pass filter; be input to analog to digital converter ADC and carry out analog to digital conversion; ADC transformation result is sent to microprocessor by data bus and exports adjusting to reduce error, improves output current precision.
Specifically; microprocessor outputs signal to input low-pass filter 201 in PWM output port output PWM; filtered signal converts the feedback voltage follower 208 of voltage to through following by inputting voltages device 202, linear optical coupling buffer circuit 203, Voltage-controlled Current Source 204, output protection circuit 205, output current Acquisition Circuit 207, output current; output current is transformed into feedback voltage low-pass filter 209 after voltage to analog to digital converter 210 analog to digital conversion, and transformation result is delivered to microprocessor.
It is for the high-frequency harmonic in PWM is filtered out that PWM output signal is transported to input low-pass filter circuit 201, become the DC voltage of ratio to obtain a PWM pulse-width signal dutycycle of exporting with microprocessor, filtered DC voltage is connected to the load that following by inputting voltages device 202 alleviates output end of microprocessor mouth to improve the input impedance of circuit, the carrying load ability that simultaneously improves circuit is beneficial to drive linear optical coupling isolation circuit 203, linear optical coupling buffer circuit 203 is the external interference signals that may introduce for isolating long-distance transmissions, avoid interference in the weak signal that signal seals in microprocessor.Voltage-controlled Current Source 204 control circuits, are to convert the output voltage after linear optical coupling isolation to corresponding proportional current signal to export, and output protection circuit is not damaged for the protection of output circuit.Backfeed loop module 206 objects are accurately to control output current size; output current Acquisition Circuit 207 is after the cold junction of output protection circuit gathers output current; convert voltage to; and after feedback voltage follower 208 and 209 filtering of feedback voltage low-pass filter; be input to analog to digital converter (ADC) 210 and carry out analog to digital conversion; ADC transformation result is sent to microprocessor by data bus and exports adjusting to reduce error, improves output current precision
Microprocessor is according to the good output current value of programming, first regulate PWM output signal, pwm signal passes through after the input low-pass filter 201 in circuit, high fdrequency component in signal is filtered out, be varied to corresponding proportional d. c. voltage signal, then output after following by inputting voltages device 202.In order to improve the antijamming capability of circuit, the d. c. voltage signal of output is isolated through linear optical coupling, converts the current signal of theoretical output through the voltage signal of light-coupled isolation by Voltage-controlled Current Source 204 to.In order to control the precision of output current, by output current Acquisition Circuit 207, convert the voltage signal of feedback to, follow and feed back after 209 filtering of low pass voltage filter are processed and change by A/D the digital signal that becomes microprocessor identification through feedback voltage follower 208, microprocessor is by the signal of back production, calculate the error of electric current output, and readjust the size of output pwm signal, and then reduced the error of output DC current.
Fig. 3 is the circuit structure diagram of the utility model preferred embodiment.In the utility model preferred embodiment, for 4-20mA DC current source circuit, wherein resistance R 1, capacitor C 1, electric capacity E1 composition input low-pass filter, operational amplifier U1A composition following by inputting voltages device, CU1 is the filter capacity of its power supply VCC, optocoupler U3 and resistance R 2, R3, R4 and capacitor C 3 form linear optical coupling buffer circuit, capacitor C 2 is the filter capacitor of its positive supply S+12V, operational amplifier U2A and NPN triode Q1 and resistance R 5-7 composition Voltage-controlled Current Source, operational amplifier U2A uses positive-negative power S+12V, S-12V, diode D1 and surge absorbing device TVS1 composition output protection circuit, RL is load, U6 is serially connected in the cold junction composition output current Acquisition Circuit of output current, operational amplifier U8A is connected into follower composition feedback voltage follower, resistance R 34, capacitor C 46 forms feedback voltage low-pass filter, its output CURNT is connected to analog to digital converter ADC, VCC in figure, VCC3, VCC5, S+12V, S-12V is power supply, GND and SGND are reference ground separately.
Visible, a kind of DC current source based on the closed-loop control of PWM technology of the utility model is by adopting PWM pulse modulation technology to export voltage, avoid employing DA pio chip to control, save hardware cost, and simplify circuit, adopted loop control theory simultaneously, output current is carried out to feedback collection, and convert digital signal to, microprocessor calculates output error by the back production to output signal, then automatically compensate output again, output accuracy is higher than traditional output circuit, and does not need manual intervention.
Above-described embodiment is illustrative principle of the present utility model and effect thereof only, but not for limiting the utility model.Any those skilled in the art all can, under spirit of the present utility model and category, modify and change above-described embodiment.Therefore, rights protection scope of the present utility model, should be as listed in claims.
Claims (3)
1. the DC current source circuit based on the closed-loop control of PWM technology, at least comprises:
Forward current generation module, is connected in the PWM output port of microprocessor, and the pulse width modulated signal conversion that PWM output port is produced is direct current proportional to pulsewidth;
Backfeed loop module, is connected in the output terminal of described forward current generation module, converts digital voltage signal to and is sent to microprocessor processing after the output current collection of described forward current generation module.
2. a kind of DC current source circuit based on the closed-loop control of PWM technology as claimed in claim 1; it is characterized in that: described forward current generation module comprises input low-pass filter, following by inputting voltages device, linear optical coupling buffer circuit, Voltage-controlled Current Source, output protection circuit; the PWM output port of microprocessor described in described input low-pass filter input termination, described input low-pass filter, described following by inputting voltages device, described linear optical coupling buffer circuit, described Voltage-controlled Current Source, the cascade successively of described output protection circuit.
3. a kind of DC current source circuit based on the closed-loop control of PWM technology as claimed in claim 2, it is characterized in that: described backfeed loop module comprises output current Acquisition Circuit, feedback voltage follower, feedback voltage low-pass filter and analog to digital converter, described current collection circuit is connected in the cold junction of described output protection circuit, to converting voltage to after output current collection, and after described feedback voltage follower and the filtering of described feedback voltage low-pass filter, be input to described analog to digital converter and carry out analog to digital conversion, analog to digital conversion result is sent to described microprocessor by data bus.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320763799.0U CN203745941U (en) | 2013-11-26 | 2013-11-26 | DC current source circuit based on closed-loop control of PWM (Pulse-Width Modulation) technology |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320763799.0U CN203745941U (en) | 2013-11-26 | 2013-11-26 | DC current source circuit based on closed-loop control of PWM (Pulse-Width Modulation) technology |
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| CN203745941U true CN203745941U (en) | 2014-07-30 |
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| CN201320763799.0U Expired - Fee Related CN203745941U (en) | 2013-11-26 | 2013-11-26 | DC current source circuit based on closed-loop control of PWM (Pulse-Width Modulation) technology |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106373374A (en) * | 2016-11-28 | 2017-02-01 | 长沙广义变流技术有限公司 | Small signal isolation transmission circuit |
| CN106714394A (en) * | 2015-07-27 | 2017-05-24 | 深圳市世明伦电子有限公司 | Intelligent-dimming and non-flickering LED driving power supply |
| CN107608436A (en) * | 2017-09-27 | 2018-01-19 | 深圳巴斯巴科技发展有限公司 | A kind of control circuit and method that variable voltage is exported using PWM mode |
| CN108469775A (en) * | 2018-06-29 | 2018-08-31 | 赵明 | One kind 4 ~ 20mA signal isolation circuits and multifunctional isolating transmitter |
| CN108811225A (en) * | 2017-05-04 | 2018-11-13 | 深圳市帝莱特照明有限公司 | A kind of middle low power intelligent lighting dims color-changed LED driving power without stroboscopic |
| CN108983859A (en) * | 2018-08-08 | 2018-12-11 | 上海精密计量测试研究所 | Programmable power supply |
| CN110557021A (en) * | 2019-09-29 | 2019-12-10 | 广东科高电器有限公司 | current automatic adjustment high-precision compensation circuit for atomizer |
| CN110657859A (en) * | 2019-09-29 | 2020-01-07 | 广东科高电器有限公司 | Waterless dry-burning detection circuit |
| CN110687951A (en) * | 2019-10-15 | 2020-01-14 | 博能传动(苏州)有限公司 | High-precision voltage-controlled current source capable of being quickly turned off |
| CN110955185A (en) * | 2019-12-11 | 2020-04-03 | 中国科学院合肥物质科学研究院 | Superconducting switch heater power supply based on operational amplifier |
| CN110955172A (en) * | 2019-10-30 | 2020-04-03 | 中国船舶重工集团公司第七一九研究所 | Electric isolation type 0-20 mA driving circuit with output self-detection function |
| CN114371335A (en) * | 2021-12-29 | 2022-04-19 | 苏州联讯仪器有限公司 | High-precision digital source meter |
| CN114460999A (en) * | 2022-01-04 | 2022-05-10 | 珠海格力电器股份有限公司 | Adjustable circuit, controller and electronic equipment |
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2013
- 2013-11-26 CN CN201320763799.0U patent/CN203745941U/en not_active Expired - Fee Related
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106714394A (en) * | 2015-07-27 | 2017-05-24 | 深圳市世明伦电子有限公司 | Intelligent-dimming and non-flickering LED driving power supply |
| CN106373374A (en) * | 2016-11-28 | 2017-02-01 | 长沙广义变流技术有限公司 | Small signal isolation transmission circuit |
| CN108811225A (en) * | 2017-05-04 | 2018-11-13 | 深圳市帝莱特照明有限公司 | A kind of middle low power intelligent lighting dims color-changed LED driving power without stroboscopic |
| CN107608436A (en) * | 2017-09-27 | 2018-01-19 | 深圳巴斯巴科技发展有限公司 | A kind of control circuit and method that variable voltage is exported using PWM mode |
| CN108469775A (en) * | 2018-06-29 | 2018-08-31 | 赵明 | One kind 4 ~ 20mA signal isolation circuits and multifunctional isolating transmitter |
| CN108469775B (en) * | 2018-06-29 | 2023-11-28 | 赵明 | 4-20 mA signal isolation circuit and multifunctional isolation transmitter |
| CN108983859A (en) * | 2018-08-08 | 2018-12-11 | 上海精密计量测试研究所 | Programmable power supply |
| CN110657859B (en) * | 2019-09-29 | 2021-12-10 | 广东科高电器有限公司 | Waterless dry-burning detection circuit |
| CN110557021A (en) * | 2019-09-29 | 2019-12-10 | 广东科高电器有限公司 | current automatic adjustment high-precision compensation circuit for atomizer |
| CN110657859A (en) * | 2019-09-29 | 2020-01-07 | 广东科高电器有限公司 | Waterless dry-burning detection circuit |
| CN110687951A (en) * | 2019-10-15 | 2020-01-14 | 博能传动(苏州)有限公司 | High-precision voltage-controlled current source capable of being quickly turned off |
| CN110955172A (en) * | 2019-10-30 | 2020-04-03 | 中国船舶重工集团公司第七一九研究所 | Electric isolation type 0-20 mA driving circuit with output self-detection function |
| CN110955185A (en) * | 2019-12-11 | 2020-04-03 | 中国科学院合肥物质科学研究院 | Superconducting switch heater power supply based on operational amplifier |
| CN114371335A (en) * | 2021-12-29 | 2022-04-19 | 苏州联讯仪器有限公司 | High-precision digital source meter |
| CN114371335B (en) * | 2021-12-29 | 2022-10-18 | 苏州联讯仪器有限公司 | High-precision digital source meter |
| CN114460999A (en) * | 2022-01-04 | 2022-05-10 | 珠海格力电器股份有限公司 | Adjustable circuit, controller and electronic equipment |
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| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140730 Termination date: 20171126 |