CN108832929A - Low power consumption high-precision analog quantity isolation circuit - Google Patents
Low power consumption high-precision analog quantity isolation circuit Download PDFInfo
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- CN108832929A CN108832929A CN201810518970.9A CN201810518970A CN108832929A CN 108832929 A CN108832929 A CN 108832929A CN 201810518970 A CN201810518970 A CN 201810518970A CN 108832929 A CN108832929 A CN 108832929A
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- circuit
- pwm
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- trigger
- isolation circuit
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
- H03M1/50—Analogue/digital converters with intermediate conversion to time interval
- H03M1/52—Input signal integrated with linear return to datum
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Abstract
The present invention provides a kind of low power consumption high-precision analog quantity isolation circuit, V/PWM circuit including Magnetic isolation circuit, for voltage signal to be converted to pwm signal and the PWM/V circuit for being used to for pwm signal being reduced into voltage signal；The input terminal of the V/PWM circuit is connect with analog voltage input, and the output end of V/PWM circuit is connect with the input terminal of Magnetic isolation circuit, and the output end of Magnetic isolation circuit is connect with the input terminal of PWM/V circuit；By the way that analog voltage signal is converted to pwm signal in the present invention, after through Magnetic isolation circuit, pwm signal is reduced to analog voltage signal again, it is output voltage and input voltage in accurate linear relationship, circuit structure is simple, easy to accomplish, and cost is relatively low, and power consumption is very low, low-power consumption requirement needed for meeting industrial automation instrument.
Description
Technical field
The present invention relates to electronic field more particularly to a kind of low power consumption high-precision analog quantity isolation circuits.
Background technique
In the two-wire system instrument and meter of industrial automation, for the interference free performance for enhancing instrument, it is often necessary to input letter
Number with output signal electrical isolation, many for digital signal partition method and isolating device power consumption is also very low, compares appearance
It easily realizes, and has for analog signal isolating method following several, wherein V-F, F-V partition method first convert analog quantity
For frequency signal (V-F), then frequency signal is isolated by digital form, isolation end using F-V circuit by frequency signal also
Original is at analog signal, that is, voltage signal, and this method precision is high, good linearity, but general V-F conversion chip power consumption is both greater than
4mA is unsatisfactory for two-wire system low-power consumption requirement；Linear optical coupling isolation method have the advantages that it is low in energy consumption, but due to optic coupling element
Light decay is larger at any time, and temperature drift is big, and linear poor, precision is not high；Transformer isolation, equally have the advantages that it is low in energy consumption, but its
Complex process, at high cost, consistency is difficult to ensure.
Summary of the invention
In view of the foregoing deficiencies of prior art, the present invention provides a kind of low power consumption high-precision analog quantity isolation circuit,
To solve the above technical problems.
Low power consumption high-precision analog quantity isolation circuit provided by the invention, including：
V/PWM circuit, for the analog voltage signal of input to be converted to pwm signal；
Magnetic isolation circuit, for pwm signal to be isolated；
PWM/V circuit, for pwm signal to be reduced into voltage signal.
Further, the V/PWM circuit includes integrating circuit and trigger, the output end and trigger of the integrating circuit
Input terminal connection, the trigger be Schmidt trigger.
Further, the V/PWM circuit further includes analog switch, and the output end of trigger and the control terminal of analog switch connect
It connects, when trigger exports high level, reference voltage is switched to by analog switch and connect with the in-phase end of integrating circuit；Work as touching
When sending out device output low level, low level is switched to by analog switch and is connect with the in-phase end of integrating circuit.
Further, when the trigger exports high level, the Schmidt trigger is connected by analog switch, integral
Capacitor in circuit starts to charge, when output voltage rises to the comparison upper limit of Schmidt trigger, the output of the trigger
It being lower, the capacitor electric discharge of the integrating circuit reduces output voltage, when being down to the comparison lower limit of Schmidt trigger, institute
The capacitor for stating integrating circuit starts to charge, and generates recurrent pulse.
Further, the PWM/V circuit includes filter circuit and for pwm signal to be converted to patrolling for d. c. voltage signal
Volume module, the first input end of the logic module are connect with power supply, the second input terminal and magnetic of the logic module every
Output end connection from circuit, the output end of the logic module are connect with filter module.
Further, the logic module is and logic module.
Further, the filter module is the RC filter circuit for removing high-frequency signal.
Further, the analog switch is single-pole double-throw switch (SPDT).
Beneficial effects of the present invention：Low power consumption high-precision analog quantity isolation circuit in the present invention, by by analog voltage
Signal is converted to pwm signal, is reduced to analog voltage signal after through Magnetic isolation circuit, then by pwm signal, is output voltage
It is in accurate linear relationship with input voltage, circuit structure is simple, and easy to accomplish, cost is relatively low, and power consumption is very low, meets
The requirement of low-power consumption needed for industrial automation instrument.
Detailed description of the invention
Fig. 1 is the functional block diagram of low power consumption high-precision analog quantity isolation circuit in the embodiment of the present invention.
Fig. 2 is the circuit diagram of the V/PWM of low power consumption high-precision analog quantity isolation circuit in the embodiment of the present invention.
Fig. 3 is the circuit diagram of the PWM/V of low power consumption high-precision analog quantity isolation circuit in the embodiment of the present invention.
Specific embodiment
Illustrate embodiments of the present invention below by way of specific specific example, those skilled in the art can be by this specification
Other advantages and efficacy of the present invention can be easily understood for disclosed content.The present invention can also pass through in addition different specific realities
The mode of applying is embodied or practiced, the various details in this specification can also based on different viewpoints and application, without departing from
Various modifications or alterations are carried out under spirit of the invention.It should be noted that in the absence of conflict, following embodiment and implementation
Feature in example can be combined with each other.
It should be noted that illustrating the basic structure that only the invention is illustrated in a schematic way provided in following embodiment
Think, only shown in schema then with related component in the present invention rather than component count, shape and size when according to actual implementation
Draw, when actual implementation kenel, quantity and the ratio of each component can arbitrarily change for one kind, and its assembly layout kenel
It is likely more complexity.
As shown in Figure 1, the low power consumption high-precision analog quantity isolation circuit in the present embodiment, mainly include Magnetic isolation circuit,
For voltage signal to be converted to the V/PWM circuit of pwm signal and is used to for pwm signal being reduced into the PWM/V electricity of voltage signal
Road；The input terminal of the V/PWM circuit is connect with analog voltage input, output end and the Magnetic isolation circuit of V/PWM circuit
Input terminal connection, the output end of Magnetic isolation circuit are connect with the input terminal of PWM/V circuit.
In the present embodiment, the effect of V/PWM circuit be the analog voltage Vin of input is converted to it is linear therewith
Pwm signal (duty ratio is adjustable square-wave signal), then exported again by the Magnetic isolation circuit PWM signal of low-power consumption to isolation
Pwm signal is reduced into voltage signal Vout using PWM/V circuit in isolation end by end.V/PWM circuit includes the product interconnected
Parallel circuit and trigger, it further includes analog switch U31 that the trigger in the present embodiment, which is Schmidt trigger, and the integral is electric
The output end on road is connect with the input terminal of Schmidt trigger U29, and the output end of Schmidt trigger U29 passes through analog switch
U31 is connect with the output end of the Schmidt trigger, as shown in Fig. 2, the integrating circuit in the present embodiment is mainly by resistance
R55, resistance R56, capacitor C57 and operational amplifier U27B are formed, and the S pin in analog switch U31 is control terminal, and A is public
End, when S is high level, B2 is connect with A；When S is low level, B1 is connect with A.
When Schmidt trigger U29 exports high level, analog switch connects B2, if input voltage Vn<Vi<Vp, then this
When integrator to capacitor C charging increase voltage V0, charging current is:
Ii=(Vp-Vi)/R (1)
When V0 is increased to Schmidt comparator upper limit VH, U29 output is lower and analog switch is made to connect 0V, at this time capacitor
C57 electric discharge reduces V0, and discharge current is:
I0=(Vi -0)/R (2)
When V0 is down to comparator lower limit VL, U29 overturning makes capacitor charging again, and then U29 output end generates recurrent pulse.
If positive pulsewidth is T1, negative pulsewidth is T2, and according to charge balance concept, the charge/discharge electricity amount of capacitor is equal, i.e.,
T1 × (Vp-Vi)/R=T2 × (Vi -0)/R (3)
When V 0 is down to comparator lower limit V L, U29 overturning makes capacitor charging again, and then U29 output end generates period arteries and veins
Punching.If positive pulsewidth is T1, negative pulsewidth is T 2, and according to charge balance concept, the charge/discharge electricity amount of capacitor is equal, i.e. duty ratio
D=T1/ (T1+T2)=(Vi-0)/(Vp-V0) (4)
In the present embodiment, D=V i/V p, only conversion accuracy related with reference voltage is high for the duty ratio of pulse.This electricity
Reference voltage Vp and Vn are switched using analog switch in road, wherein Vn passes through pull down resistor and realizes with directly connecing circuit, Vn=
After 0V, Vp are divided using high-precision voltage reference by precision resistance, obtained after low maladjustment voltage amplifier does voltage follow.
In the present embodiment, PWM/V circuit includes filter circuit and for pwm signal to be converted to d. c. voltage signal
The first input end of logic module, the logic module is connect with power supply, the second input terminal and magnetic of the logic module
The output end of isolation circuit connects, and the output end of the logic module is connect with filter module, as shown in figure 3, in the present embodiment
Magnetic isolation circuit be preferably Magnetic isolation chip ADUM1240, logic module is two inputs and door U4, and pwm signal passes through Magnetic isolation
After processing of circuit, input and door U4 realize the conversion of pwm signal to DC voltage, and output is by RC filtering removal radio-frequency component.
Logic chip U4 selects SN74AHC1G08 chip, two inputs and logic.An input terminal (1 foot) of U4 as shown in the figure connects power supply
Power supply ensure that logic chip output exports same phase with SIG signal.
It in the present embodiment, is VOUT=VOL* (1-D)+VOH*D=VOL+ (VOH- with door U4 output voltage virtual value
VOL)*D
Wherein, VOH is U4 output high level voltage value；VOL is that U4 exports low level voltage value；D is SIG signal (PWM)
Duty ratio；
VOL representative value is 0V；VOH representative value is supply voltage.
Therefore output voltage VO UT=VOH*D, and aforementioned calculating D=Vin/Vp, VOH are U4 supply voltage, obtain VOUT
=VOH*Vin/Vp, if rationally setting U4 supply voltage and Vp value i.e. may make output voltage VO UT and input voltage vin at
Accurate linear relationship.Above-mentioned main chip U29, U30, U31 power consumption is respectively 0.2mA, 34uA, 10uA, and the sum of power consumption is
0.235uA meets low-power consumption requirement well.
The above-described embodiments merely illustrate the principles and effects of the present invention, and is not intended to limit the present invention.It is any ripe
The personage for knowing this technology all without departing from the spirit and scope of the present invention, carries out modifications and changes to above-described embodiment.Cause
This, institute is complete without departing from the spirit and technical ideas disclosed in the present invention by those of ordinary skill in the art such as
At all equivalent modifications or change, should be covered by the claims of the present invention.
Claims (8)
1. a kind of low power consumption high-precision analog quantity isolation circuit, which is characterized in that including：
V/PWM circuit, for the analog voltage signal of input to be converted to pwm signal；
Magnetic isolation circuit, for pwm signal to be isolated；
PWM/V circuit, for pwm signal to be reduced into voltage signal.
2. low power consumption high-precision analog quantity isolation circuit according to claim 1, which is characterized in that the V/PWM circuit
Including integrating circuit and trigger, the output end of the integrating circuit and the input terminal of trigger are connected, and the trigger is to apply
Schmitt trigger.
3. low power consumption high-precision analog quantity isolation circuit according to claim 2, it is characterised in that：The V/PWM circuit
It further include analog switch, the output end of trigger and the control terminal of analog switch connect, when trigger exports high level, benchmark
Voltage is switched to by analog switch and is connect with the in-phase end of integrating circuit；When trigger exports low level, low level passes through
Analog switch is switched to be connect with the in-phase end of integrating circuit.
4. low power consumption high-precision analog quantity isolation circuit according to claim 3, it is characterised in that：When the trigger is defeated
Out when high level, the Schmidt trigger is connected by analog switch, and the capacitor in integrating circuit starts to charge, when output electricity
When pressure rises to the comparison upper limit of Schmidt trigger, the output of the trigger is lower, and the capacitor electric discharge of the integrating circuit makes
Output voltage reduces, and when being down to the comparison lower limit of Schmidt trigger, the capacitor of the integrating circuit is started to charge, and generates week
Phase pulse.
5. low power consumption high-precision analog quantity isolation circuit according to claim 1, it is characterised in that：The PWM/V circuit
Logic module including filter circuit and for pwm signal to be converted to d. c. voltage signal, the first of the logic module are defeated
Enter end to connect with power supply, the second input terminal of the logic module is connect with the output end of Magnetic isolation circuit, the logic
The output end of module is connect with filter module.
6. low power consumption high-precision analog quantity isolation circuit according to claim 5, it is characterised in that：The logic module is
With logic module.
7. low power consumption high-precision analog quantity isolation circuit according to claim 5, it is characterised in that：The filter module is
For removing the RC filter circuit of high-frequency signal.
8. low power consumption high-precision analog quantity isolation circuit according to claim 3, it is characterised in that：The analog switch is
Single-pole double-throw switch (SPDT).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810518970.9A CN108832929A (en) | 2018-05-28 | 2018-05-28 | Low power consumption high-precision analog quantity isolation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810518970.9A CN108832929A (en) | 2018-05-28 | 2018-05-28 | Low power consumption high-precision analog quantity isolation circuit |
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| Publication Number | Publication Date |
|---|---|
| CN108832929A true CN108832929A (en) | 2018-11-16 |
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| CN201810518970.9A Pending CN108832929A (en) | 2018-05-28 | 2018-05-28 | Low power consumption high-precision analog quantity isolation circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117406653A (en) * | 2023-12-12 | 2024-01-16 | 浙江国利信安科技有限公司 | Analog output device and industrial controller |
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|---|---|---|---|---|
| CN2912065Y (en) * | 2006-06-19 | 2007-06-13 | 南京南自电力仪表有限公司 | Analogue capacity outputting device of motor protection device |
| CN201918010U (en) * | 2010-12-17 | 2011-08-03 | 中国科学院电工研究所 | Voltage-current collecting and transmitting device for high-voltage system |
| US20120068614A1 (en) * | 2010-09-21 | 2012-03-22 | Avago Technologies Ecbu (Singapore) Pte. Ltd. | Transmitting and Receiving Digital and Analog Signals across an Isolator |
| CN205142179U (en) * | 2015-11-23 | 2016-04-06 | 常熟理工学院 | Low frequency analog signal keeps apart change power transmission way |
| CN205647498U (en) * | 2016-05-27 | 2016-10-12 | 福州福光百特自动化设备有限公司 | High accuracy PWM rotary die volume of planning output circuit |
-
2018
- 2018-05-28 CN CN201810518970.9A patent/CN108832929A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2912065Y (en) * | 2006-06-19 | 2007-06-13 | 南京南自电力仪表有限公司 | Analogue capacity outputting device of motor protection device |
| US20120068614A1 (en) * | 2010-09-21 | 2012-03-22 | Avago Technologies Ecbu (Singapore) Pte. Ltd. | Transmitting and Receiving Digital and Analog Signals across an Isolator |
| CN201918010U (en) * | 2010-12-17 | 2011-08-03 | 中国科学院电工研究所 | Voltage-current collecting and transmitting device for high-voltage system |
| CN205142179U (en) * | 2015-11-23 | 2016-04-06 | 常熟理工学院 | Low frequency analog signal keeps apart change power transmission way |
| CN205647498U (en) * | 2016-05-27 | 2016-10-12 | 福州福光百特自动化设备有限公司 | High accuracy PWM rotary die volume of planning output circuit |
Non-Patent Citations (1)
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| 张文学 孙圣和: "一种精密线性 PWM 电路的研究", 《仪器仪表学报》, pages 267 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117406653A (en) * | 2023-12-12 | 2024-01-16 | 浙江国利信安科技有限公司 | Analog output device and industrial controller |
| CN117406653B (en) * | 2023-12-12 | 2024-02-27 | 浙江国利信安科技有限公司 | Analog output device and industrial controller |
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