CN205647498U - High accuracy PWM rotary die volume of planning output circuit - Google Patents
High accuracy PWM rotary die volume of planning output circuit Download PDFInfo
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- CN205647498U CN205647498U CN201620501665.5U CN201620501665U CN205647498U CN 205647498 U CN205647498 U CN 205647498U CN 201620501665 U CN201620501665 U CN 201620501665U CN 205647498 U CN205647498 U CN 205647498U
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Abstract
The utility model provides a high accuracy PWM rotary die volume of planning output circuit, includes: singlechip PWM signal modules for output PWM pulse signal, the power adopts switching power supply for export two sets of isolation mains voltage UC and UR, magnetism buffer circuit, including magnetism isolation chip, PWM pulse signal is the output square -wave signal signal after magnetism buffer circuit handles, the voltage reference source circuit for alternate into precision voltage reference UA with power output's isolation mains voltage UR, low pass filter for it changes into DC voltage signal to keep apart chip output square -wave signal signal with magnetism, VI converting circuit for convert the DC voltage signal of low pass filter output into analog signal. The utility model discloses a magnetism isolation technique owing to cancelled the photoelectric conversion link that optoelectronic coupler influence efficiency, has eliminated the unstable current transmission rate of photoelectric coupling, and the nonlinearity is transmitted, aspect problems such as temperature and life. Owing to adopt isolation technique, avoid PWM pulse signal to influence analog signal's fluctuation, improved analog signal's stability.
Description
Technical field
This utility model relates to analog signal output field, a kind of uses Magnetic isolation technology that the conversion of digital PWM pulse signal is generated the circuit of curtage analogue signal.
Background technology
In electronics and automatic technology use, it is often necessary to synchronize to use single-chip microcomputer and digital to analog converter to realize the digital signal conversion to analogue signal.In industry spot instrument in the market, conventional PWM turns analogue signal and typically uses the even isolation of light, and after the even isolation of light, signal is more weak, also additionally to add PWM shaping circuit, and circuit is more complicated.Along with the development of industrial technology, the speed of optocoupler, LED are aging, reliability, power consumption are crossed the shortcomings such as height and also come out, and the greatest problem of tradition photo-coupler product is to there is weakness in terms of reliability and operability.Along with aging, their performance declines the most therewith；Further, when operating at relatively high temperatures, actually ageing process can be aggravated.
Utility model content
The purpose of this utility model is to overcome the shortcoming of prior art, it is provided that a kind of High-Accuracy PWM turns analogue quantity output circuit.
For solving above-mentioned technical problem, this utility model have employed techniques below measure:
A kind of High-Accuracy PWM turns analogue quantity output circuit, including:
SCM PWM signaling module, is used for exporting pwm pulse signal；
Power supply, uses Switching Power Supply, for two groups of insulating power supply voltage UC and UR of output；
Magnetic isolation circuit, including Magnetic isolation chip, described pwm pulse signal exports square-wave signal after Magnetic isolation processing of circuit；
Voltage reference source circuit, for being transformed into precision voltage reference UA by the insulating power supply voltage UR that power supply exports；
Low pass filter, for changing into d. c. voltage signal by Magnetic isolation chip output square-wave signal；
V/I change-over circuit, for being converted to analog signals by the d. c. voltage signal that low pass filter exports.
This utility model can also be the most perfect by techniques below measure:
As improving further, described Magnetic isolation circuit includes Magnetic isolation chip U1 and electric capacity C7,1 foot of described U1 is connected to the UC end of power supply, 4 feet of U1 are connected to 3 feet of shunt capacitance C7 between 1 foot of GND, U1 and 4 feet, described U1 and connect SCM PWM pulse signal, 8 feet of U1 connect the reference voltage UA that voltage reference circuit produces, 5 feet of U1 are connected to 6 feet of AGND, U1 and are connected to the input of low pass filter, and export square-wave signal to it.
As improving further, described voltage reference source circuit includes resistance R2 and stabilivolt Q1, and one end of described R2 connects the UR end of power supply, and the other end of R2 connects the N pole of stabilivolt Q1, and the other end of stabilivolt Q1 connects AGND.
As improving further, described low pass filter includes that resistance R4, R6 and electric capacity C1, C2, described R4 one end are connected with 6 feet of U1, the R4 other end is connected with R6, C1, the other end of C1 is connected to the other end of AGND, R6 and is connected with C2, V/I change-over circuit, and the C2 other end is connected to AGND.
nullAs improving further，Described V/I change-over circuit includes chip U3A，Resistance R7、R8、R9、R10，Electric capacity C3、C4、C5、C6，Field effect transistor Q2、Switch S1 and analog signals outfan OUT-、OUT+，Described chip U3A and R7、R8 connects，The R7 other end connects the reference voltage UA that voltage reference circuit produces，The R8 other end and C4、R9、The source electrode of field effect transistor Q2 connects，C4、The R9 other end is connected to AGND，C6 in parallel between 1 foot and 2 feet of U3A，8 feet of U3A connect the UR end of power supply，4 feet of U3A are connected to AGND，C3 in parallel between 8 feet and 4 feet of U3A，1 foot of U3A connects the grid of field effect transistor Q2，The drain electrode of described field effect transistor Q2 connects C5、R10 and analog signals outfan OUT-，The described C5 other end connects UR end and the analog signals outfan OUT+ of power supply，The described R10 other end connects S1，S1 other end connection mode analog quantity signal output part OUT+.
As improving further, the frequency of described pwm pulse signal is 1.5 KHz ~ 2.5KHz and resolution is more than 16.
As improving further, described analog signals is current signal or the voltage signal of 1-5V of 4-20mA, and during switch S1 Guan Bi, the analog signals of output is voltage signal, and when switching S1 disconnection, the analog signals of output is current signal.
Compared with prior art, this utility model has the advantage that
1, pwm pulse signal exports square-wave signal after Magnetic isolation chip internal Schmidt's shaping, Magnetic isolation.Use Magnetic isolation technology, affect the opto-electronic conversion link of efficiency owing to eliminating photoelectrical coupler, eliminate photoelectric coupling instability electric current transfer rate, nonlinear transport, temperature and service life etc. aspect problem.Isolation avoids pwm pulse signal to affect the fluctuation of analog signals, improves the stability of analog signals.
2, low pass filter uses the circuit structure of Order RC filtering, gets rid of the interference of external environment further, increases the reliability in adverse circumstances.
3, V/I change-over circuit carries out amplifier, feeds back and compare d. c. voltage signal, produces a control level and controls field effect transistor Q2, then is exported analog signals by field effect transistor Q2.Have that control mode is simple, load linearity stability high, the advantage that circuit anti-interference ability is good.The analog signals precision height of output meets most application scenarios demand.
4, by arranging switch S1, during switch S1 Guan Bi, the analog signals of output is voltage signal, and when switching S1 disconnection, the analog signals of output is current signal.So, user can obtain voltage signal or current signal as required, only need to be switched over by switch S1, meet the different demands of client, applied range.
Accompanying drawing explanation
Accompanying drawing 1 is the theory diagram that this utility model High-Accuracy PWM turns analogue quantity output circuit；
Accompanying drawing 2 is the circuit diagram that this utility model High-Accuracy PWM turns analogue quantity output circuit；
Accompanying drawing 3 is that this utility model High-Accuracy PWM turns pwm pulse signal production method schematic diagram in analogue quantity output circuit.
Detailed description of the invention
With detailed description of the invention, this utility model is described in further detail below in conjunction with the accompanying drawings.
Refer to Fig. 1 to Fig. 3, a kind of High-Accuracy PWM turns analogue quantity output circuit, including:
SCM PWM signaling module, is used for exporting pwm pulse signal；
Power supply, uses Switching Power Supply, for two groups of insulating power supply voltage UC and UR of output；
Magnetic isolation circuit, including Magnetic isolation chip, described pwm pulse signal exports square-wave signal after Magnetic isolation processing of circuit；
Voltage reference source circuit, for being transformed into precision voltage reference UA by the insulating power supply voltage UR that power supply exports；
Low pass filter, for changing into d. c. voltage signal by Magnetic isolation chip output square-wave signal；
V/I change-over circuit, for being converted to analog signals by the d. c. voltage signal that low pass filter exports.
In embodiment, High-Accuracy PWM turns analogue quantity output circuit, and pwm pulse signal conversion is produced voltage-type or the signal of current mode, processes the signal obtained in instrument and meter through this circuit structure.The frequency of described pwm pulse signal is 1.5 KHz ~ 2.5KHz and resolution is more than 16.Final analog signals is current signal or the voltage signal of 1-5V of 4-20mA.Pwm pulse signal exports square-wave signal after Magnetic isolation chip internal Schmidt's shaping, Magnetic isolation.Use Magnetic isolation technology, eliminating photoelectrical coupler affect the opto-electronic conversion link of efficiency, eliminate photoelectric coupling instability electric current transfer rate, nonlinear transport, temperature and service life etc. aspect problem.Isolation avoids pwm pulse signal to affect the fluctuation of analog signals, improves the stability of analog signals.
Described Magnetic isolation circuit includes Magnetic isolation chip U1 and electric capacity C7,1 foot of described U1 is connected to the UC end of power supply, 4 feet of U1 are connected to GND, shunt capacitance C7 between 1 foot and 4 feet of U1,3 feet of described U1 connect SCM PWM pulse signal, and 8 feet of U1 connect 5 feet of reference voltage UA, U1 that voltage reference circuit produces and are connected to AGND, 6 feet of U1 are connected to the input of low pass filter, and export square-wave signal to it.
Described voltage reference source circuit includes resistance R2 and stabilivolt Q1, and one end of described R2 connects the UR end of power supply, and the other end of R2 connects the N pole of stabilivolt Q1, and the other end of stabilivolt Q1 connects AGND.
Described low pass filter includes that resistance R4, R6 and electric capacity C1, C2, described R4 one end are connected with 6 feet of U1, and the R4 other end is connected with R6, C1, and the other end of C1 is connected to the other end of AGND, R6 and is connected with C2, V/I change-over circuit, and the C2 other end is connected to AGND.Low pass filter uses the circuit structure of Order RC filtering, gets rid of the interference of external environment further, increases the reliability in adverse circumstances.
nullDescribed V/I change-over circuit includes chip U3A，Resistance R7、R8、R9、R10，Electric capacity C3、C4、C5、C6，Field effect transistor Q2、Switch S1 and analog signals outfan OUT-、OUT+，Described chip U3A and R7、R8 connects，The R7 other end connects the reference voltage UA that voltage reference circuit produces，The R8 other end and C4、R9、The source electrode of field effect transistor Q2 connects，C4、The R9 other end is connected to AGND，C6 in parallel between 1 foot and 2 feet of U3A，8 feet of U3A connect the UR end of power supply，4 feet of U3A are connected to AGND，C3 in parallel between 8 feet and 4 feet of U3A，1 foot of U3A connects the grid of field effect transistor Q2，The drain electrode of described field effect transistor Q2 connects C5、R10 and analog signals outfan OUT-，The described C5 other end connects UR end and the analog signals outfan OUT+ of power supply，The described R10 other end connects S1，S1 other end connection mode analog quantity signal output part OUT+.
V/I change-over circuit carries out amplifier, feeds back and compare d. c. voltage signal, produces a control level and controls field effect transistor Q2, then is exported analog signals by field effect transistor Q2.Have that control mode is simple, load linearity stability high, the advantage that circuit anti-interference ability is good.The analog signals precision height of output meets most application scenarios demand.
By arranging switch S1, during switch S1 Guan Bi, the analog signals of output is voltage signal, and when switching S1 disconnection, the analog signals of output is current signal.So, user can obtain voltage signal or current signal as required, only need to be switched over by switch S1, meet the different demands of client, applied range.
See Fig. 3, the pwm pulse signal in embodiment, it is that the method using two pulses of duty one unit of difference to form according to a certain percentage obtains, makes pwm pulse signal have higher frequency and resolution.Such as, monolithic counter frequency is 4MHz, manages to produce the pwm pulse of 2KHz.According to the conventional PWM way of output, resolution is only 2000.And when using said method, the signal selecting dutycycle to be 1000/2000 and 1001/2000 such as pwm pulse, but marginal signal just cannot export.As, 50 pulse combined become a new PWM cycle signal, can 25 employing dutycycles be the signal of 1000/2000 in the past, and rear 25 employing dutycycles are the signal of 1001/2000, then the cycle of a set of pulses is 25ms.Keeping the pulse frequency of PWM and the frequency of enumerator, according to cycle=resolution * counter pulse time, can calculate now resolution is 100000.
The foregoing is only preferred embodiment of the present utility model; not in order to limit this utility model; all within spirit of the present utility model and principle, any modification, equivalent substitution and improvement etc. done, should be included within the scope of this utility model protection.
Claims (7)
1. High-Accuracy PWM turns an analogue quantity output circuit, including:
SCM PWM signaling module, is used for exporting pwm pulse signal；
Power supply, uses Switching Power Supply, for two groups of insulating power supply voltage UC and UR of output；
Magnetic isolation circuit, including Magnetic isolation chip, described pwm pulse signal exports square-wave signal after Magnetic isolation processing of circuit；
Voltage reference source circuit, for being transformed into precision voltage reference UA by the insulating power supply voltage UR that power supply exports；
Low pass filter, for changing into d. c. voltage signal by Magnetic isolation chip output square-wave signal；
V/I change-over circuit, for being converted to analog signals by the d. c. voltage signal that low pass filter exports.
High-Accuracy PWM the most according to claim 1 turns analogue quantity output circuit, it is characterized in that: described Magnetic isolation circuit includes Magnetic isolation chip U1 and electric capacity C7,1 foot of described U1 is connected to the UC end of power supply, 4 feet of U1 are connected to GND, shunt capacitance C7 between 1 foot and 4 feet of U1,3 feet of described U1 connect SCM PWM pulse signal, 8 feet of U1 connect the reference voltage UA that voltage reference circuit produces, 5 feet of U1 are connected to AGND, 6 feet of U1 are connected to the input of low pass filter, and export square-wave signal to it.
High-Accuracy PWM the most according to claim 1 turns analogue quantity output circuit, it is characterized in that: described voltage reference source circuit includes resistance R2 and stabilivolt Q1, one end of described R2 connects the UR end of power supply, and the other end of R2 connects the N pole of stabilivolt Q1, and the other end of stabilivolt Q1 connects AGND.
High-Accuracy PWM the most according to claim 2 turns analogue quantity output circuit, it is characterized in that: described low pass filter includes resistance R4, R6 and electric capacity C1, C2, described R4 one end is connected with 6 feet of U1, the R4 other end is connected with R6, C1, the other end of C1 is connected to AGND, the other end of R6 is connected with C2, V/I change-over circuit, and the C2 other end is connected to AGND.
nullHigh-Accuracy PWM the most according to claim 4 turns analogue quantity output circuit，It is characterized in that: described V/I change-over circuit includes chip U3A，Resistance R7、R8、R9、R10，Electric capacity C3、C4、C5、C6，Field effect transistor Q2、Switch S1 and analog signals outfan OUT-、OUT+，Described chip U3A and R7、R8 connects，The R7 other end connects the reference voltage UA that voltage reference circuit produces，The R8 other end and C4、R9、The source electrode of field effect transistor Q2 connects，C4、The R9 other end is connected to AGND，C6 in parallel between 1 foot and 2 feet of U3A，8 feet of U3A connect the UR end of power supply，4 feet of U3A are connected to AGND，C3 in parallel between 8 feet and 4 feet of U3A，1 foot of U3A connects the grid of field effect transistor Q2，The drain electrode of described field effect transistor Q2 connects C5、R10 and analog signals outfan OUT-，The described C5 other end connects UR end and the analog signals outfan OUT+ of power supply，The described R10 other end connects S1，S1 other end connection mode analog quantity signal output part OUT+.
High-Accuracy PWM the most according to claim 1 turns analogue quantity output circuit, it is characterised in that: the frequency of described pwm pulse signal is 1.5 KHz ~ 2.5KHz and resolution is more than 16.
High-Accuracy PWM the most according to claim 5 turns analogue quantity output circuit, it is characterized in that: described analog signals is current signal or the voltage signal of 1-5V of 4-20mA, during switch S1 Guan Bi, the analog signals of output is voltage signal, and when switching S1 disconnection, the analog signals of output is current signal.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201620501665.5U CN205647498U (en) | 2016-05-27 | 2016-05-27 | High accuracy PWM rotary die volume of planning output circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201620501665.5U CN205647498U (en) | 2016-05-27 | 2016-05-27 | High accuracy PWM rotary die volume of planning output circuit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107835001A (en) * | 2017-10-27 | 2018-03-23 | 上海辰竹仪表有限公司 | Processing method, system, signal processing apparatus and the medium of pulse width modulation wave |
| CN108062054A (en) * | 2017-12-22 | 2018-05-22 | 深圳市英威腾电气股份有限公司 | A kind of analog signals output circuit |
| CN108832929A (en) * | 2018-05-28 | 2018-11-16 | 重庆川仪自动化股份有限公司 | Low power consumption high-precision analog quantity isolation circuit |
| CN112557737A (en) * | 2020-12-04 | 2021-03-26 | 上海航天控制技术研究所 | Simple isolation voltage threshold discrimination circuit |
-
2016
- 2016-05-27 CN CN201620501665.5U patent/CN205647498U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107835001A (en) * | 2017-10-27 | 2018-03-23 | 上海辰竹仪表有限公司 | Processing method, system, signal processing apparatus and the medium of pulse width modulation wave |
| CN108062054A (en) * | 2017-12-22 | 2018-05-22 | 深圳市英威腾电气股份有限公司 | A kind of analog signals output circuit |
| CN108832929A (en) * | 2018-05-28 | 2018-11-16 | 重庆川仪自动化股份有限公司 | Low power consumption high-precision analog quantity isolation circuit |
| CN112557737A (en) * | 2020-12-04 | 2021-03-26 | 上海航天控制技术研究所 | Simple isolation voltage threshold discrimination circuit |
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Denomination of utility model: High accuracy PWM rotary die volume of planning output circuit Effective date of registration: 20191204 Granted publication date: 20161012 Pledgee: Fujian strait bank Co., Ltd. Fuzhou Jinshan sub branch Pledgor: Fuzhou Fuguang Baite Automatical Equipment Co., Ltd. Registration number: Y2019350000077 |
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| PE01 | Entry into force of the registration of the contract for pledge of patent right |