CN1601910A - So H2 line-frequency synchronous reverse integration A/D converter - Google Patents
So H2 line-frequency synchronous reverse integration A/D converter Download PDFInfo
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Abstract
The converter includes power circuit, shaping circuit of power frequency signal, adjustable proportional integral amplifying circuit for signal to be measured, comparator circuit of discharge integration voltage, 5V/12V level transfer circuit for controlling integral and a single chip system circuit. Characters are that the converter also includes a synchronous control switching circuit in power frequency, a holding circuit of signal, adder circuit for signals to be measured at zero cross at positive and negative half cycle, and an inverse integration circuit for constant current discharge etc. The A/D converter turns signal to be measured to pulse width signal through integration circuit and comparator circuit, and further to control A/D converter to solve issue of interference in magnetic field in power frequency and stray magnetic field of centralized temperature measurement system in large area for multiple points. Features are simple structure and high efficiency.
Description
Technical field
The present invention relates to the conversion of analog quantity and digital quantity,, relate in particular to temperature survey and control that the large tracts of land multiple spot is concentrated as the analog quantity of the temperature sensor signal of telecommunication and the conversion of digital quantity.
Background technology
The invention of the synchronous A/D of 50Hz power frequency (analog quantity converting digital amount) converter comes from the exploitation of the storage grain system for detecting temperature of " research of grain system for detecting temperature among the large-scale silo group " project.Be for solve=50Hz power frequency during 30 times/second (national Specification storage grain temperature detection speed) picking rates disturbs and design, realized that storage grain temp measuring system concentrates the purpose of A/D conversion.Solved also simultaneously that existing storage grain temp measuring system is many because of the A/D translation circuit in working service, adjustable device is many, caused the consistency of quantification poor, failure rate height, problem difficult in maintenance.
In today of electronic technology, computer technology and sensor technology develop rapidly, the physical quantity signal of a lot of conditions can be become the signal of telecommunication of analog quantity by sensing technology, again the signal of telecommunication of analog quantity be become the digital quantity signal of telecommunication and store, transmit and show.Wherein, the method that analog quantity becomes digital quantity (A/D conversion) has a variety of, and commonly used just has successive approximation, voltage ratio than type, biproduct somatotype, V/F attribute A/D converter.
Storage grain thermometric is that the large tracts of land multiple spot is concentrated a kind of of thermometric, and that its characteristics are put exactly is many, face is big, environment is abominable, adopts when concentrating the A/D conversion, and analog signal is disturbed strongly by 50Hz power frequency magnetic field and other stray magnetic fields in transmission.Practice shows that when concentrating the A/D conversion, because temperature sensor is different in size interrelated to the line of centrostigma, the difference of its distributed capacitance and connection resistances adds that the influence of interference signal causes the repetitive error of A/D conversion to meet the demands.Therefore, for the contradiction between solution speed and the interference, present storage grain temp measuring system all adopts a plurality of A/D converters way of conversion simultaneously at the scene.What most systems adopted is double integrator or V/F attribute A/D converter.All is furnished with relevant functional circuit around each A/D converter, comprising single chip circuit, switching circuit, amplifying circuit, benchmark regulating circuit, communicating circuit, power circuit etc.Therefore, the long-term use can change because of the electrical quantity of adjustable device and other electronic devices and components, causes the faults such as damage of the not normal and electronic devices and components of A/D conversion, brings difficulty to troubleshooting of faults.In addition, because environmental condition is abominable, the failure rate of system and fault point will increase year by year, and the consistency of quantification and precision are also incited somebody to action variation year by year.
Along with the maturation of digital temperature sensor technology, existing a part of temp measuring system uses digital temperature sensor.That is to say that the variation of temperature signal does not need other circuit just to become digital quantity, the temperature sensor of some is connected on the cable of one two core, only need be furnished with communicating circuit and get final product by the bus reading of data.Its advantage is, line is few, and adjustable element is few in the system; Shortcoming is that node is not concentrated, anticorrosion difficulty; The damage of a transducer can cause the working sensor on the bus not normal, and maintenance is difficulty relatively.
Summary of the invention
The present invention is intended to the 50Hz power frequency synchronous, measured signal addition when the measured signal during with positive half cycle zero passage keeps with the negative half period zero passage becomes measured signal into 50 times/second the A/D converter that the pulse width signal that is directly proportional with the measured signal amplitude is given the single-chip microcomputer counting by constant-current discharge integration (being anti-integration) circuit and comparator circuit.When solving the large tracts of land multiple spot and concentrate the concentrated A/D conversion of temp measuring system, the problem that analog signal is disturbed by 50Hz power frequency magnetic field and other stray magnetic fields in transmission.Solve storage grain system for detecting temperature at present simultaneously, many because of electronic component, the A/D translation circuit is many, adjustable device is many, lean on the smart circuit of program running many, works and failure rate high the problem that keep in repair, maintenance difficulties is big in the adverse circumstances at the scene.
Technical solution of the present invention is achieved in that
A kind of synchronous and monolithic processor controlled by the 50Hz power frequency, measured signal addition when the measured signal when aligning the half cycle zero passage keeps with the negative half period zero passage becomes measured signal into the synchronous noresidue reverse integration A/D converter of 50Hz power frequency that the pulse width signal that is directly proportional with the measured signal amplitude is given the single-chip microcomputer counting by anti-integrating circuit of noresidue and comparator circuit.
The functional circuit of forming the synchronous reverse integration A/D converter of 50Hz power frequency has:
A 220V exchanges the power circuit of input, is the functional circuit power supply of the synchronous reverse integration A of 50Hz power frequency/D converter with 220V alternating current transformation, rectification, filtering, voltage stabilizing;
A 50Hz power frequency component shaping circuit becomes the 50Hz sine wave into square wave, and the measured signal maintained switch when the 12V square wave level of output is controlled positive half cycle zero passage uses;
A measured signal proportion adjustable integrating amplification circuit is amplified to certain amplitude with measured signal, eliminates the high frequency clutter interference simultaneously;
A discharge integral voltage comparison circuit is used for each measured signal is become the square-wave signal that is directly proportional with signal amplitude;
The 5V/12V level-conversion circuit of a Single-chip Controlling integration is used for the 5V level translation of single-chip microcomputer output is become the 12V level, and the control analog switch is to electric capacity charging and discharge integration;
A microcontroller system circuit is used to control the zero-time of integrating capacitor charging and discharge integration, the data of measuring the measured signal square width and preserving square width;
A 50Hz square wave level 12V/5V translation circuit, the 12V square wave level translation that 50Hz power frequency component shaping circuit is exported becomes 5V square wave level to use for single-chip microcomputer;
A 50Hz power frequency synchronous control switch circuit, the measured signal half cycle that is used to control after the amplification ends by, half cycle;
A measured signal holding circuit is used for switching circuit and closes the maintenance measured signal of having no progeny;
Measured signal adder circuit when measured signal during a positive half cycle zero passage and negative half period zero passage is used to eliminate the interference of 50Hz power frequency;
The anti-integrating circuit of a constant-current discharge is used to bleed off each measured signal and fills electric charge in integrating capacitor.
Technical solution of the present invention also comprises:
The 220V of reverse integration A/D converter that described 50Hz power frequency is synchronous exchanges the power circuit of input, it is characterized in that described 220V exchanges the power circuit of input by the 220V power transformer, the diode full-wave rectifying circuit, low frequency filtering electric capacity, high-frequency filter capacitor, the integrated three-terminal voltage-stabilizing chip of+5V LM7805, the integrated three-terminal voltage-stabilizing chip of+12V LM7812, the integrated three-terminal voltage-stabilizing chip of-12V LM7912 forms, alternating current 220V voltage becomes double cross stream 15V by power transformer, after full-wave rectification and filtering, give+the integrated three-terminal voltage-stabilizing chip of 5V LM7805 and+12V integrated three-terminal voltage-stabilizing chip LM7812 and-the integrated three-terminal voltage-stabilizing chip of 12V LM7912 carries out voltage stabilizing and High frequency filter, output+12V,-12V and+the 5V direct voltage.
The 50Hz power frequency component shaping circuit of reverse integration A/D converter that described 50Hz power frequency is synchronous is characterized in that described 50Hz power frequency component shaping circuit is made up of a current-limiting resistance, two pressure limiting diodes and a voltage comparator.The 50Hz power frequency component takes out from the secondary winding of power transformer.By resistance current limliting and diode over the ground pressure limiting give the zero passage voltage comparator input terminal, by comparator the 50Hz sine wave is become square wave output, divide two-way again, the maintained switch of one tunnel control measured signal when 50Hz power frequency zero passage, the level converter of leading up to uses for the Single-chip Controlling integration.
The measured signal proportion adjustable integrating amplification circuit of reverse integration A/D converter that described 50Hz power frequency is synchronous is characterized in that described measured signal proportion adjustable integrating amplification circuit is made up of operational amplifier, input divider resistance, ratio regulator potentiometer integrating capacitor, output filter capacitor.Its function is to amplify measured signal and eliminate the high frequency clutter interference.The output of operational amplifier divides two-way, leads up to resistance as one road signal of resistor adder, and another road is by analog switch and holding circuit another road signal as adder.
The discharge integral voltage comparison circuit of reverse integration A/D converter that described 50Hz power frequency is synchronous, it is characterized in that described discharge integral voltage comparison circuit by integrated chip and output pull-up resistor form.The square wave of voltage comparator circuit output is given the single-chip microcomputer counting.
The 5V/12V level-conversion circuit of the Single-chip Controlling integration of reverse integration A/D converter that described 50Hz power frequency is synchronous is characterized in that the 5V/12V level-conversion circuit of described Single-chip Controlling integration is made up of triode, transistor base resistance, transistor collector resistance.The base stage of triode links to each other with single-chip microcomputer by resistance, and the collector electrode of triode links to each other with the 12V power supply by resistance, and the collector electrode output of triode is connected with the control end of the analog switch of control integration.
The microcontroller system circuit of reverse integration A/D converter that described 50Hz power frequency is synchronous is characterized in that described microcontroller system circuit is made up of circuit such as single-chip microcomputer and SCM peripheral circuit and data storages.Single-chip microcomputer reads 50Hz power frequency zero cross signal by the I/O mouth, regularly send according to zero cross signal again and patrol and examine instruction and timing controlled analog switch, and the time of discharge each time counted quantize and the machine-readable use of getting is kept supplying in the data preservation integrating capacitor charging and discharge.
The 50Hz square wave level 12V/5V translation circuit of reverse integration A/D converter that described 50Hz power frequency is synchronous is characterized in that described 50Hz square wave level 12V/5V translation circuit is made up of a pull-up resistor and an analog switch.One termination of pull-up resistor+5V power supply wherein, the input of another termination analog switch, the output head grounding current potential of analog switch, the control end of analog switch is taken over the no-voltage comparator output terminal, and the 5V square wave level of conversion uses for the Single-chip Controlling integration.
The 50Hz power frequency synchronous control switch circuit of reverse integration A/D converter that described 50Hz power frequency is synchronous is characterized in that described 50Hz power frequency synchronous control switch circuit is made up of an analog switch and a resistance, an electric capacity.The control signal of analog switch is provided by no-voltage comparator output, and the measured signal by resistance and electric capacity transposition control ends by, another half cycle at power frequency one half cycle.
The measured signal holding circuit of reverse integration A/D converter that described 50Hz power frequency is synchronous is characterized in that described measured signal holding circuit is made up of voltage follower and electric capacity.Measured signal is charged to electric capacity by analog switch, the high impedance of high impedance when utilizing analog switch to turn-off and voltage follower input, the voltage of measured signal when the electric capacity two ends keep analog switch to turn-off outputs to one road input of adder by voltage follower.
Measured signal adder circuit when measured signal during the positive half cycle zero passage of reverse integration A/D converter that described 50Hz power frequency is synchronous and negative half period zero passage, the measured signal adder circuit when measured signal when it is characterized in that described positive half cycle zero passage and negative half period zero passage is made up of two resistance and a voltage follower.Wherein, one termination of a resistance be the voltage of analog switch measured signal when turn-offing, one termination of another resistance be the measured signal voltage of amplifier output, the other end of two resistance links to each other and obtains the mean value of asynchronous measured signal voltage, and the measured signal after the interference of elimination 50Hz power frequency is amplified output through voltage follower.
The constant-current discharge integrating circuit of reverse integration A/D converter that described 50Hz power frequency is synchronous, it is characterized in that described constant-current discharge integrating circuit is by an analog switch, an operational amplifier, a voltage stabilizing chip, an integrating capacitor, a discharge resistance is formed, discharging and recharging of integrating capacitor is to be controlled by analog switch according to the zero crossing of 50Hz power frequency by single-chip microcomputer, the charge volume of integrating capacitor is directly proportional with each measured signal voltage, the discharging current of integrating capacitor equals voltage stabilizing chip both end voltage than discharge resistance resistance, and the integrating capacitor both end voltage is output into the zigzag waveform by operational amplifier.
The advantage of reverse integration A/D converter that the present invention compared with prior art proposes shows:
1, finishing the A/D conversion in the one-period of power frequency 50Hz is double integrator and V/F formula A/D converter (being up to 12.5 times/second) 4 times, has solved the contradiction that present storage grain temp measuring system is concentrated A/D conversion and the interference of 50Hz power frequency 30 point/seconds;
2, in the one-period of power frequency 50Hz, finish the 50Hz power frequency interference problem of the long line transmission of A/D conversion and solution small-signal, utilize weighted mean method and scalping method to overcome the 50Hz power frequency with voltage ratio than type A/D converter to disturb and to compare with approaching one by one, solve at the signal that long line transmits small-signal that begins of one-period and set up problem.
3, compare with the circuit in the analog switch of forward (also crying charging) simple integral A/D conversion is connected on charging and discharge loop respectively, solved resistance because of analog switch and caused residual and resistance temperature drift analog switch of discharge to cause the problem of charging current variation.
Description of drawings
Fig. 1 is a schematic block circuit diagram of the present invention.
Fig. 2 is circuit theory diagrams of the present invention.
Fig. 3 is a power circuit
Fig. 4 is the proportion adjustable integrating amplification circuit.
Fig. 5 is measured signal maintenance and switching circuit.
Fig. 6 is the measured signal adder circuit.
Fig. 7 is anti-integration and switching circuit.
Fig. 8 is anti-integral voltage comparison circuit.
Fig. 9 is a 50Hz power frequency component shaping circuit.
Figure 10 is a 50Hz square wave level 12V/5V translation circuit.
Figure 11 is the 5V/12V level-conversion circuit.
Figure 12 is a microcontroller system circuit.
Among Fig. 2,1, is the proportion adjustable integrating amplification circuit, 2, for measured signal maintenance and switching circuit, 3, be the measured signal adder circuit, 4, be anti-integration and switching circuit, 5, be anti-integral voltage comparison circuit, 6, be 50Hz power frequency component shaping circuit, 7, be 50Hz square wave level 12V/5V translation circuit, 8, be the 5V/12V level-conversion circuit, 9, power circuit, 10, microcontroller system circuit.
Embodiment
As shown in the figure be to utilize 50Hz power frequency component and power frequency component shaping circuit, measured signal maintenance and switching circuit, measured signal adder circuit, anti-integration and circuit etc., realized under the counting of single-chip microcomputer and control, having overcome that the 50Hz power frequency is disturbed and 50 times/second A/D converter of stray magnetic field interference.Utilize zero-crossing comparator that the signal shaping of 50Hz power frequency sine wave is become square wave, realize one tunnel measured signal conducting in the power frequency half period with this square wave control analog switch, in other half period, end the control that keeps, maintained measured signal and another road measured signal addition are sent into integrator through follower amplification output by analog switch integrating capacitor are charged.Integrator is by the Push And Release of single-chip microcomputer according to the variation control analog switch of 50Hz power frequency zero passage, the electric charge of integrating capacitor begins constant-current discharge by resistance when single-chip microcomputer sends shutoff analog switch signal, the internal counter of single-chip microcomputer begins counting simultaneously, the prolongation in time of the output voltage of integrator constantly descends, up to another input that is lower than comparator, make till the output change state of comparator.Single-chip microcomputer is received after the comparator output state changes signal and is stopped counting.And send and open the analog switch signal.
Below the functional circuit of this analog signal bus transmitter is further introduced:
1. power circuit
Power circuit by 220V power transformer, diode full-wave rectifying circuit, low frequency filtering electric capacity, high-frequency filter capacitor ,+5V circuit of three-terminal voltage-stabilizing integrated LM7805 ,+12V circuit of three-terminal voltage-stabilizing integrated LM7812 ,-12V circuit of three-terminal voltage-stabilizing integrated LM7912 etc. forms.As Fig. 3, its operation principle is: alternating current 220V voltage becomes the two 15V of interchange by the coupling of power transformer, after full-wave rectification and filtering, give+5V circuit of three-terminal voltage-stabilizing integrated LM7805 and+12V circuit of three-terminal voltage-stabilizing integrated LM7812 and-12V circuit of three-terminal voltage-stabilizing integrated LM7912 carries out voltage stabilizing and High frequency filter, output+5V ,+12V and-the 12V direct voltage.
2. proportion adjustable integrating amplification circuit
The proportion adjustable integrating amplification circuit is made up of operational amplifier, input divider resistance, ratio regulator potentiometer and integrating capacitor, output filter capacitor.As shown in Figure 4, its operation principle is: measured signal Vi is from the in-phase input end input of operational amplifier, output
Wherein
Xcf is the capacitive reactance of integrating capacitor in the formula
Formula shows that Vo and Xcf are proportional, Xcf and the frequency relation of being inversely proportional to.Therefore, this circuit suppresses the function of high frequency clutter interference signal in addition except proportional enlarging function.
3. measured signal maintenance and switching circuit
Measured signal maintenance and switching circuit are made up of capacitor C 1, C2, R1, analog switch K1, current amplifier.As shown in Figure 5, its operation principle is: the measured signal Vo after the amplification is from the A end input of analog switch K1, the Kai Heguan of K1 is by being controlled by the 50Hz power frequency component after the shaping, K1 is opened at a zero crossing, and beginning is to capacitor C 1 charging, another zero crossing K1 to the 50Hz power frequency component is closed, and makes the voltage at C1 two ends equal the voltage of Vo when 50Hz power frequency component zero crossing, and remains to K1 and be opened again.The voltage of C1 carries out current amplifier output by follower, has realized the maintenance to the signal of a last zero crossing.C2 and R1 are used to postpone the time of opening and closing of K1, to guarantee having time enough to charge to anti-integrating capacitor.
4. measured signal adder circuit
The measured signal adder circuit is made up of resistance R 2, R3 and current amplifier.As shown in Figure 6, its operation principle is: the measured signal Vo after the amplification is from the end input of R2, maintained signal is from the end input of R3, two asynchronous crossover point signal are converged mutually at the other end of R2 and R3, obtain the mean value of two signals, carry out electric current by voltage follower and amplify output.
5. anti-integration and switching circuit
Anti-integration and switching circuit are made up of resistance R 4, R5, capacitor C 3, voltage-stabiliser tube W, operational amplifier, analog switch K2.As shown in Figure 7, voltage approximately equal according to two inputs of operational amplifier in magnification region, the electric current of two inputs is approximately equal to zero characteristic, the pressure drop Uw that utilizes the voltage-stabiliser tube two ends is approximate constant characteristic in certain current range, the voltage of an input of amplifier is designed to the follower of the high voltage-stabiliser tube voltage of specific output voltage.Its operation principle is: the measured signal that (K2 opens or closes under the control of single-chip microcomputer) handled through previous circuit when K2 opens is charged to the amplitude voltage (must greater than the pressure drop at voltage-stabiliser tube W two ends) of measured signal rapidly to C3, when receiving 50Hz power frequency zero cross signal, sends by single-chip microcomputer the instruction of turn-offing K2, the electric charge of C3 discharges by R5, its discharging current
Ic＝Uw/R5
Uw and R5 are fixed values in the formula, and therefore, C3 electric current by R5 when discharge is constant current.The output voltage of operational amplifier is in C3 interdischarge interval linear change.And send into an input of comparator.
6. anti-integral voltage comparison circuit
Anti-integral voltage comparison circuit is made up of voltage comparator, R6, R7, triode.As shown in Figure 8, wherein, an input end grounding (reference point of circuit) of voltage comparator, another input links to each other with the output of anti-integrating circuit.Its operation principle is: be lower than the reference potential point of circuit when the C3 discharge makes the output of anti-integrating circuit, the output of voltage comparator changes state, gives single-chip microcomputer through the collector electrode output of triode.
7.50Hz power frequency component shaping circuit
50Hz power frequency component shaping circuit is made up of resistance R 8, R9, two diodes, voltage comparators.As shown in Figure 9, wherein, the 50Hz power frequency component is to draw from an end of the low-voltage coil of power transformer, gives voltage comparator through R8 current limliting and two diode pressure limitings, and the output of voltage comparator changes state when 50Hz power frequency component zero passage.50Hz power frequency sine wave signal is become the square wave that duty ratio equates.
8.50Hz square wave level 12V/5V translation circuit
50Hz square wave level 12V/5V translation circuit is made up of a resistance and an analog switch.As shown in figure 10, wherein, the output of the control termination 50Hz power frequency component shaping circuit of analog switch, resistance both end voltage myopia equals+5V when analog switch is opened, and resistance both end voltage myopia equals 0V when analog switch turn-offs.Use for the anti-integration of Single-chip Controlling.
9.5V/12V level-conversion circuit
The 5V/12V level-conversion circuit is made up of two resistance and a triode.As shown in figure 11, wherein, resistance connects the I/O mouth of single-chip microcomputer as the base stage current-limiting resistance of triode, and another resistance connects the 12V power supply as the collector resistance of triode.Transistor collector output connects the analog switch of anti-integrating circuit.
10. microcontroller system circuit
Microcontroller system circuit is made up of the peripheral cell of single-chip microcomputer and single-chip microcomputer.As shown in figure 12, major function is: control the analog switch of anti-integrating circuit according to the 50Hz power frequency component, according to the state record of comparator discharge time of anti-integration each time, and data are converted and preserve.In addition, also undertaking send out reconnaissance instruction and with task such as upper machine communication.
Claims (12)
1.[document source] electronic application
2.[the message in-coming date] 2004-10-18
3.[application number]
4.[claim item]
[claim 1]
Reverse integration A/D converter that a kind of 50Hz power frequency is synchronous, comprise the power circuit that exchanges input, 50Hz power frequency component shaping circuit, measured signal proportion adjustable integrating amplification circuit, discharge integral voltage comparison circuit, the 5V/12V level-conversion circuit of Single-chip Controlling integration, with a microcontroller system circuit, it is characterized in that this A/D converter also comprises a 50Hz square wave level 12V/5V translation circuit, a 50Hz power frequency synchronous control switch circuit, a measured signal holding circuit, the measured signal adder circuit when measured signal during a positive half cycle zero passage and negative half period zero passage and the anti-integrating circuit of a constant-current discharge
[claim 2]
Reverse integration A/D converter that 50Hz power frequency according to claim 1 is synchronous, it is characterized in that described 220V exchanges the power circuit of input by the 220V power transformer, the diode full-wave rectifying circuit, low frequency filtering electric capacity, high-frequency filter capacitor, the integrated three-terminal voltage-stabilizing chip of+5V LM7805, the integrated three-terminal voltage-stabilizing chip of+12V LM7812, the integrated three-terminal voltage-stabilizing chip of-12V LM7912 forms, alternating current 220V voltage becomes double cross stream 15V by power transformer, after full-wave rectification and filtering, give+the integrated three-terminal voltage-stabilizing chip of 5V LM7805 and+12V integrated three-terminal voltage-stabilizing chip LM7812 and-the integrated three-terminal voltage-stabilizing chip of 12V LM7912 carries out voltage stabilizing and High frequency filter, output+12V,-12V and+the 5V direct voltage.
[claim 3]
Reverse integration A/D converter that 50Hz power frequency according to claim 1 is synchronous, it is characterized in that described 50Hz power frequency component shaping circuit is by a current-limiting resistance, two pressure limiting diodes and a voltage comparator are formed, the 50Hz power frequency component takes out from the secondary winding of power transformer, by resistance current limliting and diode over the ground pressure limiting give the zero passage voltage comparator input terminal, by comparator the 50Hz sine wave is become square wave output, divide two-way again, the maintained switch of one tunnel control measured signal when 50Hz power frequency zero passage, the level converter of leading up to uses for the Single-chip Controlling integration.
[claim 4]
Reverse integration A/D converter that 50Hz power frequency according to claim 1 is synchronous, it is characterized in that described measured signal proportion adjustable integrating amplification circuit is made up of operational amplifier, input divider resistance, ratio regulator potentiometer integrating capacitor, output filter capacitor, the output of operational amplifier divides two-way, lead up to resistance as one road signal of resistor adder, and another road is by analog switch and holding circuit another road signal as adder.
[claim 5]
Reverse integration A/D converter that 50Hz power frequency according to claim 1 is synchronous is characterized in that described discharge integral voltage comparison circuit is made up of integrated chip and output pull-up resistor, and the square wave that voltage comparator circuit is exported is given the input of single-chip microcomputer.
[claim 6]
Reverse integration A/D converter that 50Hz power frequency according to claim 1 is synchronous, the 5V/12V level-conversion circuit that it is characterized in that described Single-chip Controlling integration is made up of triode, transistor base resistance, transistor collector resistance, the base stage of triode links to each other with single-chip microcomputer by resistance, the collector electrode of triode links to each other with the 12V power supply by resistance, and the collector electrode output of triode is connected with the control end of the analog switch of control integration.
[claim 7]
Reverse integration A/D converter that 50Hz power frequency according to claim 1 is synchronous, it is characterized in that described microcontroller system circuit is made up of circuit such as single-chip microcomputer and SCM peripheral circuit and data storages, single-chip microcomputer reads 50Hz power frequency zero cross signal by the I/O mouth, regularly send according to zero cross signal again and patrol and examine instruction and timing controlled analog switch, and the time of discharge each time counted quantize and the machine-readable use of getting is kept supplying in the data preservation integrating capacitor charging and discharge.
[claim 8]
Reverse integration A/D converter that 50Hz power frequency according to claim 1 is synchronous, it is characterized in that described 50Hz square wave level 12V/5V translation circuit is made up of a pull-up resistor and an analog switch, one termination of pull-up resistor+5V power supply wherein, the input of another termination analog switch, the output head grounding current potential of analog switch, the control end of analog switch is taken over the no-voltage comparator output terminal, and the 5V square wave level of conversion uses for the Single-chip Controlling integration.
[claim 9]
According to claim 1 or the synchronous reverse integration A/D converter of 8 described 50Hz power frequencies, it is characterized in that described 50Hz power frequency synchronous control switch circuit is made up of an analog switch and a resistance, an electric capacity, the control signal of analog switch is provided by no-voltage comparator output, and the measured signal by resistance and electric capacity transposition control ends by, another half cycle at power frequency one half cycle.
[claim 10]
According to claim 1 or the synchronous reverse integration A/D converter of 8 described 50Hz power frequencies, it is characterized in that described measured signal holding circuit is made up of voltage follower and electric capacity, measured signal is charged to electric capacity by analog switch, the high impedance of high impedance when utilizing analog switch to turn-off and voltage follower input, the voltage of measured signal when the electric capacity two ends keep analog switch to turn-off outputs to one road input of adder by voltage follower.
[claim 11]
According to claim 1 or the synchronous reverse integration A/D converter of 8 described 50Hz power frequencies, measured signal adder circuit when measured signal when it is characterized in that described positive half cycle zero passage and negative half period zero passage is made up of two resistance and a voltage follower, wherein, one termination of a resistance be the voltage of analog switch measured signal when turn-offing, one termination of another resistance be the measured signal voltage of amplifier output, the other end of two resistance links to each other and obtains the mean value of asynchronous measured signal voltage, and the measured signal after the interference of elimination 50Hz power frequency is amplified output through voltage follower.
[claim 12]
According to claim 1 or the synchronous reverse integration A/D converter of 8 described 50Hz power frequencies, it is characterized in that described constant-current discharge integrating circuit is by an analog switch, an operational amplifier, a voltage stabilizing chip, an integrating capacitor, a discharge resistance is formed, discharging and recharging of integrating capacitor is to be controlled by analog switch according to the zero crossing of 50Hz power frequency by single-chip microcomputer, the charge volume of integrating capacitor is directly proportional with each measured signal voltage, the discharging current of integrating capacitor equals voltage stabilizing chip both end voltage than discharge resistance resistance, and the integrating capacitor both end voltage is output into the zigzag waveform by operational amplifier.
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| CN 200410155383 CN1601910B (en) | 2004-10-18 | 2004-10-18 | So H2 line-frequency synchronous reverse integration A/D converter |
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| CN 200410155383 CN1601910B (en) | 2004-10-18 | 2004-10-18 | So H2 line-frequency synchronous reverse integration A/D converter |
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2004
- 2004-10-18 CN CN 200410155383 patent/CN1601910B/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102201168A (en) * | 2011-05-05 | 2011-09-28 | 重庆创远光电科技有限公司 | Power frequency synchronizer based traffic signal intellisense service system |
| CN102955415A (en) * | 2012-05-31 | 2013-03-06 | 珠海艾派克微电子有限公司 | Image box chip, image box and alarm processing method of residual recording materials |
| CN105955369A (en) * | 2016-06-20 | 2016-09-21 | 福州台江区超人电子有限公司 | Agricultural greenhouse climate control system |
| CN106598896A (en) * | 2016-12-01 | 2017-04-26 | 成都凯天电子股份有限公司 | Pulse amplitude limiting conversion circuit |
| CN110581929A (en) * | 2019-09-12 | 2019-12-17 | 周操操 | Alarm circuit of radiotherapy system |
| CN112213548A (en) * | 2020-09-28 | 2021-01-12 | 许继集团有限公司 | DC small signal measuring device and method |
Also Published As
| Publication number | Publication date |
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| CN1601910B (en) | 2012-01-11 |
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