CN202026301U - Self-calibration closed-loop analog-digital (AD) conversion circuit - Google Patents
Self-calibration closed-loop analog-digital (AD) conversion circuit Download PDFInfo
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- CN202026301U CN202026301U CN2011200782439U CN201120078243U CN202026301U CN 202026301 U CN202026301 U CN 202026301U CN 2011200782439 U CN2011200782439 U CN 2011200782439U CN 201120078243 U CN201120078243 U CN 201120078243U CN 202026301 U CN202026301 U CN 202026301U
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Abstract
The utility model belongs to an analog-digital (AD) conversion circuit and particularly relates to a self-calibration closed-loop AD conversion circuit. An analog input signal of the circuit is connected with the negative input end of an operational amplifier in an integrator by an electronic switch and a resistor R1; a reference source and the ground are connected to one end of the resistor R1 in series by the electronic switch, the other end of the resistor R1 is connected with the negative-direction input end of the operational amplifier, the positive-direction input end of the operational amplifier is connected with the ground, the negative-direction input end of the operational amplifier is connected with one end of a capacitor C1, and the other end of the capacitor C1 is connected to the output end of the operational amplifier; and meanwhile, the output end of the operational amplifier is connected with one end of a resistor R2, the other end of the resistor R2 is connected to a 14-digit A/D converter, a constant current source is connected with the negative input end of the integrator by the electronic switch, the other output end of the electronic switch is connected with the ground, the other end of the A/D converter is connected with the input end of a processor, one control port of the processor is connected with the constant current source, and the other control port of the processor is connected with the output end of the electronic switch. The self-calibration closed-loop AD conversion circuit has the effects of high accuracy and small errors.
Description
Technical field
The utility model belongs to A/D convertor circuit, is specifically related to a kind of self calibration closed loop A/D convertor circuit.
Background technology
The contradiction that common charge balance equation V/F change-over circuit exists in system applies is: on the one hand, because the circuit precision becomes oppositely relevant with maximum output frequency, this has just limited the maximum operating frequency of circuit, is exactly to have limited the maximum scale coefficient to the input of certain limit; On the other hand, enough dynamic accuracies are arranged, when guaranteeing that input signal is very little for making system, sampled value in the navigation cycle is enough big, the circuit calibration factor should be the bigger the better, and inertial navigation system is under the little acceleration condition for a long time like this, also can guarantee enough computational accuracies.Adopt common scheme can't thoroughly solve this a pair of contradiction, can only adopt compromise proposal, between precision and speed, seek balance.
The something in common of integration output A/D convertor circuit and traditional V/F transducer all is based on the operation principle of charge balance, comprise essential parts such as integrator, current source, switch, logical circuit, by the charge balance on the break-make realization integrator in switch Control current source, thus the quantized value of acquisition input voltage.But, integration output A/D convertor circuit is as a kind of self-calibrating digital output V/F transducer, also comprise parts such as input diverter switch, multidigit high-speed A/D converter, counter, the soft nuclear of Nios II, serial communication interface, thus functions such as the self calibration of realization circuit, counting, output.
Summary of the invention
The purpose of this utility model is at the prior art defective, provides a kind of computational accuracy high self calibration closed loop A/D convertor circuit.
The utility model is achieved in that a kind of self calibration closed loop A/D change-over circuit, comprises signal input part, and analog input signal is connected by the negative input end of the operational amplifier in electronic switch and resistance R 1 and the integrator; A reference source and ground are connected in series to an end of resistance R 1 by electronic switch, the other end of resistance R 1 is connected with the negative input of operational amplifier, the positive input ground connection of operational amplifier, the operational amplifier negative input is connected with an end of capacitor C 1, the other end of C1 is connected to the output of operational amplifier, the output of operational amplifier is connected with an end of resistance R 2 simultaneously, the other end of resistance R 2 is connected to 14 A/D converters, resistance R 1, resistance R 2, capacitor C 1 constitutes the integrator circuit unit jointly with operational amplifier, constant-current source is connected with the negative input end of integrator by electronic switch, another output head grounding of electronic switch, the other end of A/D converter is connected with the input of processor, a control port of processor is connected with constant-current source, another control port of processor is connected with the output of electronic switch, clock is connected with the clock port of processor, the digital signal that processor output has been changed.
Aforesaid a kind of self calibration closed loop A/D change-over circuit, wherein, processor is the EP2C8T144 chip.
Aforesaid a kind of self calibration closed loop A/D change-over circuit, wherein, electronic switch is a single-pole double-throw switch (SPDT).
Aforesaid a kind of self calibration closed loop A/D change-over circuit, wherein, electronic switch is a single-pole double-throw switch (SPDT).
Effect of the present utility model is: can obtain bigger calibration factor, improve the certainty of measurement of accelerometer, FEEDBACK CONTROL speed is lower, has improved the circuit precision, and uses AD to measure residual charge, has dwindled measure error.Adopted work/calibration mode, the input of each digital quantizer can accelerometer input, precision voltage reference, carry out between the three multiplexed, for high accuracy, miniaturization, the low cost of circuit provides assurance.Need not after connect forward-backward counter, direct digital interface can be exported flexibly.
Description of drawings
Fig. 1 is the electrical block diagram of this novel calibration closed loop A/D convertor circuit that provides.
Among the figure: 1. input signal, 2. electronic switch, 3. a reference source and ground, 4. electronic switch, 5. constant-current source, 6. integrator, 7.A/D transducer, 8. processor, 9. clock, 10. output signal.
Embodiment
As shown in Figure 1, a kind of self calibration closed loop A/D change-over circuit comprises signal input part, and analog input signal 1 is connected by the negative input end of the operational amplifier in electronic switch 2 and resistance R 1 and the integrator 6; A reference source and ground 3 are connected in series to an end of resistance R 1 by electronic switch 2, and the other end of resistance R 1 is connected with the negative input of operational amplifier, the positive input ground connection of operational amplifier.Electronic switch 2 can be thought a single-pole double-throw switch (SPDT).The operational amplifier negative input is connected with an end of capacitor C 1, and the other end of C1 is connected to the output of operational amplifier, and the output of operational amplifier is connected with an end of resistance R 2 simultaneously.The other end of resistance R 2 is connected to 14 A/D converters 7.Resistance R 1, resistance R 2, capacitor C 1 constitute the integrator circuit unit jointly with operational amplifier.Constant-current source 5 is connected with the negative input end of integrator 6 by electronic switch 4.Another output head grounding of electronic switch 4, electronic switch 4 can be thought a single-pole double-throw switch (SPDT).The other end of A/D converter 7 is connected with the input of processor 8, and what processor 8 was selected in this example is the EP2C8T144 chip.A control port (FB0) of processor 8 is connected with constant-current source 5, and another control port (S0) of processor 8 is connected with the output of electronic switch 2.Clock 9 is connected with the clock port of processor 8.The digital signal that processor 8 outputs have been changed.
The operation principle and the course of work of this circuit are: input signal 1 is by electronic switch 2, enter into integrator 6 and carry out integration, output voltage is to A/D converter 7, A/D converter 7 regularly carries out the A/D conversion, processor 8 is judged transformation result, in case the output voltage of integrator 6 exceeds set point, processor 8 starts electronic switch 4 conductings of balanced loop so, discharge the electric charge of an equivalent, the output accumulator of processor 8 inside increases rating number simultaneously, so the loop is in poised state all the time, the output accumulator of processor inside then constantly adds up, accumulated value multiply by flexible strategy and current A/D converter numerical value sum is the digital value of the input signal 1 in this new-type circuit sampling period, and promptly output signal 10.Clock signal enters into processor 8, forms sample time, regularly takes this value output signal 10 away, and processor 8 removing output accumulators are zero simultaneously, prepare for adding up next time.In theory, because the effect of integrator does not exist electric charge to lose, promptly there are not cumulative errors.If it is exactly comparator that the A/D converter among Fig. 1 is degenerated to a bit pad, A/D conversion and digital processing time ignore, and then circuit is degenerated to V/F change-over circuit commonly used at present.
This circuit has two kinds of running statuses, and a kind of is mode of operation, and another kind is a calibration mode.
Under mode of operation, input signal 1 is connected to integrator 6 by electronic switch 2.The output variable of integrator 6 is sampled by A/D converter 7 and is changed.When the output variable of integrator 6 reaches predetermined value, processor 8 begins to carry out the Balance Control again of suitable polarity, software begins the surplus of read-out integrator 6 subsequently, this surplus and the umber of pulse that is used for again balance are carried out comprehensively, output digital quantity 10 is proportional to input signal 1, realizes the function of A/D conversion.
Under calibration mode, the input of integrator 6 is by electronic switch 2 ground connection, and A/D converter 7 is operated in outside the voltage range of overshoot to determine channel error.The input of integrator 6 is connected to a reference source 3 then, carries out the ratio that passage is determined in extra conversion.When carrying out asymmetric calibration, begin negative polarity Balance Control process again, carry out positive polarity Balance Control process more at once, the output at integrator 6 carries out the AD conversion subsequently.After a calibration cycle is finished, the error constant of processor 8 storage integrators, the input of integrator 6 is switched to the port of input signal 1 by electronic switch 2, after a calibration cycle is finished, the error constant of processor 8 storage integrators 6, the input of integrator 6 is switched to the port of input signal 1 by electronic switch 2, calibrate next passage then.
Claims (4)
1. self calibration closed loop A/D change-over circuit is characterized in that: comprise signal input part, analog input signal (1) is connected by the negative input end of the operational amplifier in electronic switch (2) and resistance R 1 and the integrator (6); A reference source and ground (3) are connected in series to an end of resistance R 1 by electronic switch (2), the other end of resistance R 1 is connected with the negative input of operational amplifier, the positive input ground connection of operational amplifier, the operational amplifier negative input is connected with an end of capacitor C 1, the other end of C1 is connected to the output of operational amplifier, the output of operational amplifier is connected with an end of resistance R 2 simultaneously, the other end of resistance R 2 is connected to 14 A/D converters (7), resistance R 1, resistance R 2, capacitor C 1 constitutes the integrator circuit unit jointly with operational amplifier, constant-current source (5) is connected with the negative input end of integrator (6) by electronic switch (4), another output head grounding of electronic switch (4), the other end of A/D converter (7) is connected with the input of processor (8), a control port of processor (8) is connected with constant-current source (5), another control port of processor (8) is connected with the output of electronic switch (2), clock (9) is connected with the clock port of processor (8), the digital signal that processor (8) output has been changed.
2. a kind of self calibration closed loop A/D change-over circuit as claimed in claim 1, it is characterized in that: processor (8) is the EP2C8T144 chip.
3. a kind of self calibration closed loop A/D change-over circuit as claimed in claim 2, it is characterized in that: electronic switch (2) is a single-pole double-throw switch (SPDT).
4. a kind of self calibration closed loop A/D change-over circuit as claimed in claim 3, it is characterized in that: electronic switch (4) is a single-pole double-throw switch (SPDT).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200782439U CN202026301U (en) | 2011-03-23 | 2011-03-23 | Self-calibration closed-loop analog-digital (AD) conversion circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200782439U CN202026301U (en) | 2011-03-23 | 2011-03-23 | Self-calibration closed-loop analog-digital (AD) conversion circuit |
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| CN202026301U true CN202026301U (en) | 2011-11-02 |
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| CN2011200782439U Expired - Lifetime CN202026301U (en) | 2011-03-23 | 2011-03-23 | Self-calibration closed-loop analog-digital (AD) conversion circuit |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103338042A (en) * | 2013-06-24 | 2013-10-02 | 北京航天控制仪器研究所 | Analog-digital conversion circuit for dynamically tuned gyroscope |
| CN106153981A (en) * | 2016-05-24 | 2016-11-23 | 中国人民解放军海军工程大学 | IEPE type intelligence acceleration transducer and method of work thereof |
| CN106921389A (en) * | 2015-12-24 | 2017-07-04 | 北京自动化控制设备研究所 | A kind of REAL-TIME SELF method of voltage/frequency change-over circuit |
| CN108352839A (en) * | 2015-11-11 | 2018-07-31 | 三菱电机株式会社 | A/D conversion equipments |
| CN110531296A (en) * | 2019-08-09 | 2019-12-03 | 格威半导体(厦门)有限公司 | The gain calibration methods thereof of battery management system |
| CN111948520A (en) * | 2020-08-25 | 2020-11-17 | 上海鑫匀源科技有限公司 | Multi-path real-time monitoring power supply system for aging test and test method |
| CN113126540A (en) * | 2019-12-30 | 2021-07-16 | 新唐科技股份有限公司 | Microcontroller and control method |
-
2011
- 2011-03-23 CN CN2011200782439U patent/CN202026301U/en not_active Expired - Lifetime
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103338042A (en) * | 2013-06-24 | 2013-10-02 | 北京航天控制仪器研究所 | Analog-digital conversion circuit for dynamically tuned gyroscope |
| CN103338042B (en) * | 2013-06-24 | 2016-09-21 | 北京航天控制仪器研究所 | A kind of dynamically tuned gyro, DTG analog to digital conversion circuit |
| CN108352839A (en) * | 2015-11-11 | 2018-07-31 | 三菱电机株式会社 | A/D conversion equipments |
| CN108352839B (en) * | 2015-11-11 | 2023-02-21 | 三菱电机株式会社 | A/D converter |
| CN106921389A (en) * | 2015-12-24 | 2017-07-04 | 北京自动化控制设备研究所 | A kind of REAL-TIME SELF method of voltage/frequency change-over circuit |
| CN106153981A (en) * | 2016-05-24 | 2016-11-23 | 中国人民解放军海军工程大学 | IEPE type intelligence acceleration transducer and method of work thereof |
| CN106153981B (en) * | 2016-05-24 | 2022-09-27 | 中国人民解放军海军工程大学 | IEPE type intelligent acceleration sensor and working method thereof |
| CN110531296A (en) * | 2019-08-09 | 2019-12-03 | 格威半导体(厦门)有限公司 | The gain calibration methods thereof of battery management system |
| CN113126540A (en) * | 2019-12-30 | 2021-07-16 | 新唐科技股份有限公司 | Microcontroller and control method |
| CN113126540B (en) * | 2019-12-30 | 2023-12-15 | 新唐科技股份有限公司 | Microcontroller and control method |
| CN111948520A (en) * | 2020-08-25 | 2020-11-17 | 上海鑫匀源科技有限公司 | Multi-path real-time monitoring power supply system for aging test and test method |
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| CX01 | Expiry of patent term |
Granted publication date: 20111102 |