CN201118552Y

CN201118552Y - Economic intelligent analog/digit converter

Info

Publication number: CN201118552Y
Application number: CNU2007200985545U
Authority: CN
Inventors: 邹菁; 马英杰
Original assignee: Tianjin Source Survey System TECH Co Ltd
Current assignee: Tianjin Source Survey System TECH Co Ltd
Priority date: 2007-09-18
Filing date: 2007-09-18
Publication date: 2008-09-17
Anticipated expiration: 2017-09-18

Abstract

Disclosed is an economic intelligent analog-digital converter, comprising an analog-digital conversion circuit and a control unit operated through a singlechip. The analog-digital conversion circuit includes an integrator circuit F1, a pulse generator circuit F2 connected with the integrator circuit F1, a feedback circuit connected between the integrator circuit F1 and the pulse generator circuit F2, and a voltage reference circuit F4 connected between the set end and the reset end of the pulse generator circuit F2. The control unit includes a timer control module P1, an initialization module P2, a start module P3, a judge module P4, a data reading module P5, a linear correction module P6 and a data output module P7 which are all connected in sequence. The output end Vout of the pulse generator circuit is connected to the counting input port of the singlechip, the start module P3 in the control unit is collected by a counter, and the output signals of the economic intelligent analog-digital converter is memorized in the form of data in the data output buffer zone of the singlechip.

Description

Economical intelligent analog to digital converter

Technical field

The utility model belongs to the analog to digital converter field.

Background technology

Commonly used A/D converter spare on the market, many employings such as approach one by one at direct conversion regime, price height (especially high conversion accuracy), and the address wire that takies single-chip microcomputer many (more than 8), what have needs duplicate supply.For example: the AD1679 of U.S. AD company is 14 A/D converter spares, just needs 12V and 5V power supply, increases the instrument power burden; Minimum 10 of the line of it and single-chip microcomputer takies resource.Integrated V/F device is also arranged on the market, for example: LMX31 series V/F change-over circuit, but peripheral component is many and to the temperature coefficient and the required precision height of peripheral component when using, otherwise can influence linearity.For example: LMX31 series V/F change-over circuit, required peripheral components are at most to 18, and wherein, the Resistor-Capacitor Unit of decision output frequency must be the metalfilmresistor and the polystyrene electric capacity of low-temperature coefficient.Cause that V/F conversion produces into the output impedance that reason of nonlinear error is 1 pin of LMX31 device, it makes output current change with the variation of input voltage, thereby influence conversion accuracy, for overcoming this shortcoming, high accuracy V/F transducer has added an integrator between 1 pin and 7 pin, the operational amplifier of forming integrator requires to select for use the device of low maladjustment voltage and low offset current.This not only increases cost, and the adjustment when producing in batches, and efficient is not high.

The utility model content

The utility model is intended to overcome the deficiencies in the prior art, and a kind of economical intelligent analog to digital converter is provided.

The technical scheme that the utility model is taked is: economical intelligent analog to digital converter, comprise mould/number conversion circuit and a control unit via the single-chip microcomputer operation, wherein, mould/number conversion circuit comprises, integrator circuit, the pulse-generator circuit that is attached thereto, feedback circuit are connected between integrator circuit and the pulse-generator circuit, and voltage reference circuit is connected to the set end and the clear terminal of pulse-generator circuit; Control unit comprises: the control timer module, and initialization module starts module, judge module, the read data module, linear correcting module, data outputting module, above-mentioned sequence of modules is joined; The output of pulse-generator circuit is connected to the counting input port of single-chip microcomputer in mould/number conversion circuit, startup module at control unit is counted the device collection, and the output signal of economical intelligent analog to digital converter is kept at data output buffer in the single-chip microcomputer with the form of data.

Mould/number conversion circuit basic function and principle: finish the conversion of analog signal, pulse signal is input to the counting mouth of single-chip microcomputer to pulse signal.

The analog voltage signal that is converted, import by Vin point (end of R105), through integrating circuit F1 in Va point output sawtooth signal, the pulse square wave signal of, constant amplitude wide in Vout point (9 pin of d type flip flop 74HC74) output, variable period through pulse-generator circuit F2.The frequency and the input voltage of pulse signal are linear.By control clock signal frequency CLK, and in control timer module P1, suitable timer cycle is set, can the control transformation precision reaches 14, and have anti-power frequency interference capability by the single-chip microcomputer operation control unit.

Compared with prior art, the advantage of economical intelligent analog to digital converter is: used device is few, price is low, less demanding to components and parts, and integrating capacitor adopts magnetic sheet electric capacity just, the temperature of resistance is floated also no requirement (NR), only take a mouth line of single-chip microcomputer, need not to calibrate operational amplifier offset voltage, cooperate software programming, can carry out linearity correction in real time, and have very strong anti-power frequency interference performance, have 14 high conversion accuracy, very suitable large-scale production reaches to be used in industry spot.

Description of drawings

Fig. 1 is mould/number (V/F) change-over circuit figure in the utility model; Wherein, F1 integrator circuit, F2 pulse-generator circuit, F3 feedback circuit, F4 voltage reference circuit.

Fig. 2 is a control unit logic diagram in the utility model.Wherein, P1 control timer module, P2 initialization module, P3 start module, P4 judge module, P5 read data module, the linear correcting module of P6, P7 data outputting module.

Embodiment

Referring to accompanying drawing 1, mould in the utility model/number conversion circuit comprises, integrator circuit F1, the pulse-generator circuit F2 that is attached thereto, feedback circuit F3 is connected between integrator circuit F1 and the pulse-generator circuit F2, and voltage reference circuit F4 is connected to set end and the clear terminal of pulse-generator circuit F2.

Described integrator circuit F1 comprises operational amplifier U102B and capacitor C 101 that 105, one models of a resistance R are LF353.Input signal is entered by an end of resistance R 105, and the other end of resistance R 105 is connected to 6 pin of operational amplifier U102B and an end of capacitor C 101; The other end of capacitor C 101 is connected to 7 pin of operational amplifier U102B, exports an end of the resistance R 109 that is connected to pulse-generator circuit F2 circuit part simultaneously as integrator; 5 pin of operational amplifier U102B are connected to the Vb end of feedback circuit F3 circuit part.

Described pulse-generator circuit F2 comprises two resistance R 109 and R116, a d type flip flop U103B and the diode D102 that model is 74HC74.One end of resistance R 109 is connected to the Va end of integrator circuit F1, and the other end of resistance R 109 is connected to 12 pin (triggering input D) of d type flip flop U103B and the negative terminal of diode D102; The anode of diode D102 is connected to the end of the R107 of 8 pin (inverse output terminal Q) of d type flip flop U103B and feedback circuit F3 circuit part; Clock signal clk is connected to 11 pin (input end of clock CLK) of d type flip flop U103B; 10 pin of d type flip flop U103B (set end SD) link to each other with 13 pin (removing end CD), are connected to the Vc end of voltage reference circuit F4 circuit part simultaneously; 9 pin of d type flip flop U103B (output Q) are connected to an end of resistance R 116, link to each other with the counting input port of single-chip microcomputer as output signal Vout; The other end ground connection of resistance R 116.

Described feedback circuit F3 comprises three resistance R 106, R107 and R108.The feedback signal size is regulated by resistance R 107, R108; One end of resistance R 107 links to each other with 8 pin of the d type flip flop U103B of pulse-generator circuit F2 circuit part; The other end of resistance R 107 links to each other with an end of resistance R 108 and an end of resistance R 106, is connected to 5 pin of the operational amplifier LF353 U102B of integrator circuit F1 circuit part as the Vb point; The size of permission input negative signal can be regulated the size of resistance R 106, and the other end of resistance R 106 is connected to negative 5V power supply.The other end ground connection of resistance R 108.

Described voltage reference circuit F4 comprises 102, one voltage stabilizing circuit U104 of a resistance R and a capacitor C 108.One end of resistance R 102 is connected on the power supply VCC, the other end is connected to 2 pin of voltage stabilizing circuit U104 and an end of capacitor C 108, is connected to 10 pin (set end SD) and 13 pin (removing end CD) of the d type flip flop U103B in the pulse-generator circuit F2 circuit part as the output (Vc point) of voltage stabilizing circuit; 3 pin of voltage stabilizing circuit U104 link to each other with the other end of capacitor C 108, and link to each other with ground wire.

Referring to accompanying drawing 2, control unit comprises: control timer module P1, initialization module P2, startup module P3, judge module P4, read data module P5, linear correcting module P6, data outputting module P7, above sequence of modules is joined, only when judge module P4 is judged as not, returns judge module P4 input and re-execute.

Receive the pulse signal Vout of F2 module output in V/F (mould/number) change-over circuit, by in control timer module P1, suitable timer cycle being set, can the control transformation precision reaching 14, and have anti-power frequency interference capability, by linear correcting module P6, finish online linear the correction.Program begins to carry out to be moved from P1 to the P7 order; The counting input port that the output Vout of V/F change-over circuit is connected to single-chip microcomputer is counted the device collection at the startup module P3 of control unit, and tested voltage signal is kept at data output buffer in the single-chip microcomputer with the form of data after linear correcting module P6 handles.

In control timer module P1, the cycle of timer is set, the length in cycle influences conversion accuracy and speed, and the cycle, long more precision was high more, and speed is slow more.

In initialization module P2, the step-by-step counting unit be emptied, so that receive new data.

In starting module P3, finish the operation that starts the timer sum counter simultaneously, timer is finished by single-chip microcomputer inside, and the input pulse of counter is from the output Vout of V/F change-over circuit F2 module.

Is the timing of judging timer to being less than in judge module P4? if be less than, continue to wait for that be timed to, a sampling period finishes, and stops counting, the processing stage of entering signal.

In read data module P5, the data that read counting unit are to calculating in the buffering area.

In linear correcting module P6, handle calculating in the buffering area data, finish the linearity correction of data and range conversion etc., calculate input voltage value Vin.

In data outputting module P7, the input voltage value Vin that the P6 module is calculated is kept at the data output buffer as the output of economical intelligent analog to digital converter, with the device for reading data of the economical intelligent analog to digital converter of convenient various application.

Claims

1, economical intelligent analog to digital converter, it is characterized in that, comprise V/F change-over circuit and a control unit via the single-chip microcomputer operation, wherein, mould/number conversion circuit comprises, integrator circuit, the pulse-generator circuit that is attached thereto, feedback circuit is connected between integrator circuit and the pulse-generator circuit, and voltage reference circuit is connected to the set end and the clear terminal of pulse-generator circuit; Control unit comprises: the control timer module, and the count initialized unit module starts module, judge module, the read data module, linear correcting module, data outputting module, above-mentioned sequence of modules is joined; The output of pulse-generator circuit is connected to the counting input end of the startup module of single-chip microcomputer in mould/number conversion circuit.

2, economical intelligent analog to digital converter according to claim 1 is characterized in that, described integrator circuit comprises a resistance (R105), an operational amplifier (U102B) and an electric capacity (C101); One termination input signal of resistance (R105), the other end are connected to 6 pin of operational amplifier (U102B) and an end of electric capacity (C101); The other end of electric capacity is connected to 7 pin of operational amplifier (U102B), exports an end of the resistance (R109) that is connected to the pulse-generator circuit part simultaneously as integrator; 5 pin of operational amplifier (U102B) are connected to the branch pressure side of feedback circuit part.

3, economical intelligent analog to digital converter according to claim 1 is characterized in that, described pulse-generator circuit comprises two resistance (R109) and (R116), a d type flip flop and a diode; One end of resistance (R109) is connected to the Va end of integrator circuit, and the other end of resistance (R109) is connected to 12 pin of d type flip flop and the negative terminal of diode; The anode of diode is connected to an end of 8 pin of d type flip flop and the resistance (R107) in the feedback circuit; Clock signal is connected to 11 pin of d type flip flop; 10 pin of d type flip flop link to each other with 13 pin, and the Vc that is connected to voltage reference circuit simultaneously holds, 9 pin of d type flip flop are connected to an end of resistance (R116), links to each other with the counter input port of single-chip microcomputer as output signal; The other end ground connection of resistance (R116).

4, economical intelligent analog to digital converter according to claim 1 is characterized in that, described feedback circuit comprises three resistance (R106), (R107) and (R108); 8 pin of the trigger in one end of resistance (R107) and the pulse-generator circuit link to each other; The other end of resistance (R107) links to each other with an end of resistance (R108) and an end of resistance (R106), and voltage is connected to 5 pin of the operational amplifier in the integrator circuit as a comparison; The other end of resistance (R106) is connected to negative 5V power supply; The other end ground connection of resistance (R108).

5, economical intelligent analog to digital converter according to claim 1 is characterized in that, described voltage reference circuit comprises a resistance (R102), a voltage stabilizing circuit (U104) and an electric capacity (C108); One end of resistance (R102) is connected on the power supply, and the other end is connected to 2 pin of voltage stabilizing circuit (U104) and an end of electric capacity (C108), is connected to 10 pin and 13 pin of the trigger in the pulse-generator circuit as the output of voltage stabilizing circuit; 3 pin of voltage stabilizing circuit link to each other with the other end of electric capacity (C108), and link to each other with ground wire.