CN111030696A - High-precision analog-to-digital converter - Google Patents
High-precision analog-to-digital converter Download PDFInfo
- Publication number
- CN111030696A CN111030696A CN201911423771.0A CN201911423771A CN111030696A CN 111030696 A CN111030696 A CN 111030696A CN 201911423771 A CN201911423771 A CN 201911423771A CN 111030696 A CN111030696 A CN 111030696A
- Authority
- CN
- China
- Prior art keywords
- signal
- voltage
- module
- analog
- input
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000284 extract Substances 0.000 claims abstract description 6
- 238000001514 detection method Methods 0.000 claims description 9
- 238000000605 extraction Methods 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 description 12
- 238000010586 diagram Methods 0.000 description 6
- 230000001419 dependent effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- 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
- H03M1/20—Increasing resolution using an n bit system to obtain n + m bits
Landscapes
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Analogue/Digital Conversion (AREA)
Abstract
The invention discloses a high-precision analog-to-digital converter, which comprises: a coarse quantizer module that extracts a large signal voltage from an input signal and converts the large signal voltage into a first digital signal; the priority coding module is connected with the coarse quantizer module and is used for coding the first digital signal preferentially to obtain an M-bit digital signal; the subtraction module is connected with the coarse quantizer module, and takes the large signal voltage output by the coarse quantizer module as a common-mode voltage, the common-mode voltage is subtracted from an input signal to obtain a residual difference small signal, and the residual difference small signal is amplified; and the SAR-ADC module is connected with the subtraction module and converts the amplified residual difference small signal into an N-bit digital signal. The invention separately detects the large signal and the residual difference small signal, expands the input dynamic range, improves the precision of the analog-to-digital converter and reduces the complexity of the SAR-ADC.
Description
Technical Field
The invention relates to the technical field of integrated circuits, in particular to a high-precision analog-to-digital converter.
Background
An analog-to-digital converter is a circuit system for converting an analog signal into a digital signal, which is widely used in various electronic devices and often plays a decisive role in the whole circuit system. The main performance parameters include: signal-to-noise ratio, dynamic range, significances, conversion accuracy. There is a trade-off between input dynamic range and conversion accuracy for designing an ADC, and it is difficult to implement a high accuracy analog to digital converter with a large dynamic range.
An input signal Vin is divided into two paths ① and ② which are directly connected to the ADCs, and the front end of the amplifier comprises a judgment circuit for judging whether the signal is clipped or not and then is connected to the ADCs for conversion, wherein the ① path is responsible for converting a large input signal, the ② path is responsible for converting a small input signal, only one path of the two paths is input into the ADCs when the two paths are actually used, and the gating condition is that when an ② path signal is clipped, an ① path is gated, otherwise, a ② path signal is gated to the ADCs.
In the prior art, the following defects exist: the large dynamic range of the realization is very limited, and the selection of the channel depends on a circuit for judging whether the signal is truncated or not, so that the reliability is worse; the ADC has higher requirements, and the ADC can be used only by two or more channels of analog-to-digital converters, which undoubtedly increases the complexity and the cost; the conversion precision cannot be really improved, but the precision of the original dual-channel ADC is improved, because the scheme is only to divide the signal into the sizes for detection, but not to really separate the signal for detection.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a high-precision analog-to-digital converter, which separately detects a large signal and a residual difference small signal, expands the input dynamic range, improves the precision of the analog-to-digital converter and reduces the complexity of an SAR-ADC.
In order to solve the above technical problem, the present invention provides a high-precision analog-to-digital converter, including:
a coarse quantizer module that extracts a large signal voltage in an input signal and converts the large signal voltage into a first digital signal;
the priority coding module is connected with the coarse quantizer module and is used for coding the first digital signal preferentially to obtain an M-bit digital signal;
the subtraction module is connected with the coarse quantizer module, and takes the large signal voltage output by the coarse quantizer module as a common-mode voltage, the common-mode voltage is subtracted from an input signal to obtain a residual difference small signal, and the residual difference small signal is amplified;
the SAR-ADC module is connected with the subtraction module and converts the amplified residual difference small signal into an N-bit digital signal;
the output signal of the high-precision analog-to-digital converter is an (M + N) -bit digital signal.
Preferably, in the subtraction module, the residual difference small signal is amplified 2MAnd (4) doubling.
Preferably, the coarse quantizer module comprises a large signal extraction circuit, the large signal extraction circuit comprising a reference voltage source, M analog comparators and M voltage dividing resistors;
m voltage dividing resistors are connected in series, the voltage dividing resistors are arranged in one-to-one correspondence with the analog comparators, the M voltage dividing resistors divide the voltage of the reference voltage source to obtain a plurality of groups of voltage reference signals,
a plurality of groups of voltage reference signals are respectively input to corresponding analog comparators to be compared with input voltage to obtain 2MAnd outputting the signals.
Preferably, the priority coding module is 2M-M priority encoder, said 2MA signal output channel 2M-the M-priority encoder obtains an M-bit digital signal.
Preferably, the voltage dividing resistor is a precision resistor.
Preferably, the coarse quantizer module further comprises a large signalDetection circuit of large signal detection circuit to analog comparator 2MThe signal output is subjected to a logical operation to obtain 2MA switch control signal;
through 2MThe switch control signal extracts the voltage reference signal and recovers to obtain a large signal voltage.
Preferably, the subtraction module comprises an operational amplifier, a positive input end of the operational amplifier is connected with the input signal, and a negative input end of the operational amplifier takes a large signal voltage as a reference voltage.
The invention has the beneficial effects that:
1. the invention enables a true realization of a large dynamic range input, since the invention is based on the idea of converting the large signal of the input signal separately from the small signal, so that the input range is substantially dependent on the large signal voltage value. In the coarse quantizer module, the combination of the precise resistor voltage dividing structure and the comparator can quantize large signals, and as long as the input bit number of the priority encoder is enough, the input dynamic range can reach a considerable level.
2. The analog-to-digital converter can realize high-precision output, when a large dynamic range signal is input, the large signal voltage can be accurately detected and converted into M Bit digital quantity, and the conversion of a residual small signal is realized by utilizing an N-Bit SAR-ADC, so that (M + N) Bit data are output in parallel, and the increased M Bit is equivalent to the improvement of the conversion precision.
3. The invention has simple structure and easy realization. In practice it is very difficult to implement a fully integrated large dynamic range high accuracy analog to digital converter, and the present invention provides an alternative idea: the large signal and the small signal are separately detected and subjected to analog-to-digital conversion, and on the basis of the SAR-ADC, a large signal detection circuit and a residual difference small signal difference circuit are added, so that the target of large dynamic range and high precision is relatively easily realized.
Drawings
FIG. 1 is a schematic diagram of a prior art structure in the background art;
FIG. 2 is a schematic structural view of the present invention;
FIG. 3 is a schematic diagram of the structure of a large signal extraction circuit and a priority encoder according to the present invention;
FIG. 4 is a schematic structural diagram of a large signal detection circuit according to the present invention, wherein FIG. 4(a) is a logic operation circuit, and FIG. 4(b) is a large signal voltage recovery circuit with a switch;
FIG. 5 is a schematic diagram of a subtraction module;
FIG. 6 is a schematic structural diagram of a SAR-ADC module.
Detailed Description
The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.
Referring to fig. 2, the invention discloses a high-precision analog-to-digital converter, which comprises a coarse quantizer module, a priority coding module, a subtraction module and a SAR-ADC module.
The coarse quantizer module extracts a large signal voltage from the input signal and converts the large signal voltage into a first digital signal.
The priority coding module is connected with the coarse quantizer module and used for coding the first digital signal preferentially to obtain an M-bit digital signal.
The subtraction module is connected with the coarse quantizer module, the subtraction module uses the large signal voltage output by the coarse quantizer module as a common-mode voltage, the common-mode voltage and the input signal are subjected to difference to obtain a residual difference small signal, and the residual difference small signal is amplified.
The SAR-ADC module is connected with the subtraction module and converts the amplified residual difference small signal into an N-bit digital signal.
The output signal of the high-precision analog-to-digital converter is an (M + N) bit digital signal.
The invention enables a true realization of a large dynamic range input, since the invention is based on the idea of converting the large signal of the input signal separately from the small signal, so that the input range is substantially dependent on the large signal voltage value. In the coarse quantizer module, the combination of the precise resistor voltage dividing structure and the comparator can quantize large signals, and as long as the input bit number of the priority encoder is enough, the input dynamic range can reach a considerable level. Therefore, the scheme really realizes the input with large dynamic range.
The analog-to-digital converter can realize high-precision output, when a large dynamic range signal is input, the large signal voltage can be accurately detected and converted into M Bit digital quantity, and the conversion of a residual small signal is realized by utilizing an N-Bit SAR-ADC, so that (M + N) Bit data are output in parallel, and the increased M Bit is equivalent to the improvement of the conversion precision.
The invention has simple structure and easy realization. In practice it is very difficult to implement a fully integrated large dynamic range high accuracy analog to digital converter, and the present invention provides an alternative idea: the large signal is detected separately from the small signal and analog-to-digital converted. On the basis of the SAR-ADC, a large-signal detection circuit is added, and a residual difference small-signal difference circuit is used, so that the target of large dynamic range and high precision is relatively easily realized.
In the subtraction module, the residual difference small signal is amplified 2MAnd (4) doubling.
Referring to fig. 3, the coarse quantizer module includes a large signal extraction circuit including a reference voltage source, M analog comparators, and M voltage dividing resistors; m divider resistors are connected in series and arranged in one-to-one correspondence with the analog comparators, the M divider resistors divide the voltage of a reference voltage source to obtain a plurality of groups of voltage reference signals, the plurality of groups of voltage reference signals are respectively input to the corresponding analog comparators to be compared with the input voltage, the analog comparators output a low or high level to obtain 2MThe signal output, also determines the voltage range to which the input signal belongs. In the circuit of the priority encoder, more than two encoded signals are allowed to be input simultaneously, but the encoder internal circuit has queued all the input signals in order of priority and encoded only the one with the highest priority.
The priority encoding module is 2M-M-priority encoder, 2MA signal output channel 2M-the M-priority encoder obtains an M-bit digital signal, thus realizing the input signalThe large signal voltage of the sign is analog-to-digital converted. The divider resistor is a precision resistor.
Referring to fig. 4, the coarse quantizer module further includes a large signal detection circuit, which is 2 of the analog comparatorMThe signal output is subjected to a logical operation to obtain 2MA switch control signal. Through 2MAnd extracting a voltage reference signal by the switch control signal, and recovering to obtain a large signal voltage Vcm. Fig. 4(a) shows a logic operation circuit, and fig. 4(b) shows a large-signal voltage restoration circuit with a switch. In another embodiment, the function realized by the logic gate operation circuit in the circuit of FIG. 4 can be realized by an M-2MTo the decoder of (1).
Referring to fig. 5, the subtraction module includes an operational amplifier, the positive input terminal of which is connected to the input signal, and the negative input terminal of which uses the large signal voltage as a reference voltage. Vcm represents the large signal voltage of the input signal, which is obtained by the large signal detection circuit in the coarse quantizer, and the residual difference small signal Vin' is obtained after the difference with the input signal Vin, and the small signal is amplified by 2^ M times by using the ratio adjustment of the resistance.
The input and output relationship of the circuit is as follows:
referring to fig. 6, a schematic diagram of a SAR-ADC module is shown. The circuitry of the SAR-ADC comprises a comparator Comp, a DAC, a register, control logic, a CLK clock. The function of this module is to convert the residual difference small signal Vin' obtained by the subtraction module into N Bit digital quantity.
On one hand, the invention can improve the input dynamic range of the ADC, including but not limited to the idea of detecting the large signal voltage in the input signal and the specific circuit structure, including the idea of preferentially coding the large signal voltage; on the other hand, the invention can improve the ADC conversion precision and comprises the idea of separately detecting the large signal voltage and the small signal voltage.
The invention expands the input dynamic range and increases the conversion digit, namely improves the conversion precision on the basis of the original SAR-ADC.
The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.
Claims (7)
1. A high accuracy analog to digital converter, comprising:
a coarse quantizer module that extracts a large signal voltage in an input signal and converts the large signal voltage into a first digital signal;
the priority coding module is connected with the coarse quantizer module and is used for coding the first digital signal preferentially to obtain an M-bit digital signal;
the subtraction module is connected with the coarse quantizer module, and takes the large signal voltage output by the coarse quantizer module as a common-mode voltage, the common-mode voltage is subtracted from an input signal to obtain a residual difference small signal, and the residual difference small signal is amplified;
the SAR-ADC module is connected with the subtraction module and converts the amplified residual difference small signal into an N-bit digital signal;
the output signal of the high-precision analog-to-digital converter is an (M + N) -bit digital signal.
2. The high accuracy analog to digital converter of claim 1, wherein the subtraction module amplifies the residual difference small signal by 2MAnd (4) doubling.
3. The high precision analog-to-digital converter of claim 1, wherein the coarse quantizer module comprises a large signal extraction circuit comprising a reference voltage source, M analog comparators, and M voltage dividing resistors;
m voltage dividing resistors are connected in series, the voltage dividing resistors are arranged in one-to-one correspondence with the analog comparators, the M voltage dividing resistors divide the voltage of the reference voltage source to obtain a plurality of groups of voltage reference signals,
a plurality of groups of voltage reference signals are respectively input to corresponding analog comparators to be compared with input voltage to obtain 2MAnd outputting the signals.
4. A high accuracy analog to digital converter as claimed in claim 3, characterized in that said priority coding block is 2M-M priority encoder, said 2MA signal output channel 2M-the M-priority encoder obtains an M-bit digital signal.
5. A high accuracy analog to digital converter as claimed in claim 3, in which the divider resistance is a precision resistance.
6. The high precision analog to digital converter of claim 3, wherein the quantizer module further comprises a large signal detection circuit to analog comparator 2MThe signal output is subjected to a logical operation to obtain 2MA switch control signal;
through 2MThe switch control signal extracts the voltage reference signal and recovers to obtain a large signal voltage.
7. The high accuracy analog to digital converter of claim 1, wherein the subtraction module comprises an operational amplifier having a positive input connected to the input signal and a negative input referenced to a large signal voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911423771.0A CN111030696A (en) | 2019-12-31 | 2019-12-31 | High-precision analog-to-digital converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911423771.0A CN111030696A (en) | 2019-12-31 | 2019-12-31 | High-precision analog-to-digital converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111030696A true CN111030696A (en) | 2020-04-17 |
Family
ID=70201810
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911423771.0A Pending CN111030696A (en) | 2019-12-31 | 2019-12-31 | High-precision analog-to-digital converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111030696A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112383311A (en) * | 2020-11-19 | 2021-02-19 | 珠海零边界集成电路有限公司 | Successive approximation type analog-digital converter and data conversion method thereof |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020167437A1 (en) * | 2001-05-09 | 2002-11-14 | Shinji Tanabe | Analog-to-digital converter including a series of quantizers interconnected in cascade |
| CN102983863A (en) * | 2012-12-18 | 2013-03-20 | 天津大学 | First-stage circuit structure of pipelined analog-to-digital converter |
| CN104506196A (en) * | 2014-12-30 | 2015-04-08 | 天津大学 | High-speed high-precision two-step type analog-digital converter |
| CN104993831A (en) * | 2015-07-31 | 2015-10-21 | 中国科学院电子学研究所 | Time-interleaving Pipeline-SAR type ADC circuit |
| CN105024697A (en) * | 2015-08-28 | 2015-11-04 | 西安电子科技大学 | 12-bit high speed streamline analog-to-digital converter with background calibration function |
| US9191021B1 (en) * | 2014-12-12 | 2015-11-17 | Freescale Semiconductor, Inc. | Analog-to-digital converter with controlled error calibration |
| CN105187066A (en) * | 2015-08-04 | 2015-12-23 | 广州润芯信息技术有限公司 | Digital to analog converter |
| CN107682014A (en) * | 2017-08-02 | 2018-02-09 | 西安理工大学 | A kind of mixed type ADC system and its method for improving resolution ratio and speed |
| CN107994903A (en) * | 2017-12-15 | 2018-05-04 | 北京特邦微电子科技有限公司 | Analog to digital conversion circuit and production line analog-digital converter |
| CN110336561A (en) * | 2019-07-05 | 2019-10-15 | 中国电子科技集团公司第二十四研究所 | A kind of flow-line modulus converter and its output calibration method |
-
2019
- 2019-12-31 CN CN201911423771.0A patent/CN111030696A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020167437A1 (en) * | 2001-05-09 | 2002-11-14 | Shinji Tanabe | Analog-to-digital converter including a series of quantizers interconnected in cascade |
| CN102983863A (en) * | 2012-12-18 | 2013-03-20 | 天津大学 | First-stage circuit structure of pipelined analog-to-digital converter |
| US9191021B1 (en) * | 2014-12-12 | 2015-11-17 | Freescale Semiconductor, Inc. | Analog-to-digital converter with controlled error calibration |
| CN104506196A (en) * | 2014-12-30 | 2015-04-08 | 天津大学 | High-speed high-precision two-step type analog-digital converter |
| CN104993831A (en) * | 2015-07-31 | 2015-10-21 | 中国科学院电子学研究所 | Time-interleaving Pipeline-SAR type ADC circuit |
| CN105187066A (en) * | 2015-08-04 | 2015-12-23 | 广州润芯信息技术有限公司 | Digital to analog converter |
| CN105024697A (en) * | 2015-08-28 | 2015-11-04 | 西安电子科技大学 | 12-bit high speed streamline analog-to-digital converter with background calibration function |
| CN107682014A (en) * | 2017-08-02 | 2018-02-09 | 西安理工大学 | A kind of mixed type ADC system and its method for improving resolution ratio and speed |
| CN107994903A (en) * | 2017-12-15 | 2018-05-04 | 北京特邦微电子科技有限公司 | Analog to digital conversion circuit and production line analog-digital converter |
| CN110336561A (en) * | 2019-07-05 | 2019-10-15 | 中国电子科技集团公司第二十四研究所 | A kind of flow-line modulus converter and its output calibration method |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112383311A (en) * | 2020-11-19 | 2021-02-19 | 珠海零边界集成电路有限公司 | Successive approximation type analog-digital converter and data conversion method thereof |
| CN112383311B (en) * | 2020-11-19 | 2024-06-07 | 珠海零边界集成电路有限公司 | Successive approximation type analog-digital converter and data conversion method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7576677B2 (en) | Pipeline A/D converter converting analog signal to digital signal | |
| KR101512098B1 (en) | SAR ADC using C-R hybrid DAC | |
| US9432046B1 (en) | Successive approximation analog-to-digital converter | |
| US7161523B1 (en) | Systems and methods for a self-organizing analog-to-digital converter | |
| US10084470B2 (en) | Analogue-digital converter of non-binary capacitor array with redundant bit and its chip | |
| US8854243B2 (en) | AD converter circuit and ad conversion method | |
| Kumar et al. | Design & implementation of low power 3-bit flash adc in 0.18 µm cmos | |
| CN106877869B (en) | Capacitor sorting method capable of improving linearity of resistance-capacitance type successive approximation analog-to-digital converter | |
| CN110401447B (en) | MDAC type time domain ADC structure without operational amplifier | |
| US7209068B1 (en) | Analog to digital converter elements and methods for using such | |
| CN107769784B (en) | Oversampling type Pipeline SAR-ADC system | |
| CN104716961A (en) | Successive-approximation type analog-digital converter | |
| CN107863966A (en) | A kind of gradually-appoximant analog-digital converter electric capacity optimization method for intelligence sensor | |
| CN104579347A (en) | Analog-to-digital converter | |
| CN106374926B (en) | High speed leggy ramp type analog-digital converter | |
| CN103427841A (en) | System and method for increasing column-parallel single-slope ADC (analog to digital converter) conversion rate | |
| CN111030696A (en) | High-precision analog-to-digital converter | |
| CN104682958A (en) | Noise-shaping flash successive approximation register analog-to-digital converter (Noise-Shaping Flash-SAR ADC) | |
| US11159171B1 (en) | Digital slope analog to digital converter device and signal conversion method | |
| CN1135704C (en) | Floating-point analog-to-digital converter | |
| US8704695B2 (en) | Analog-to-digital converter | |
| US8264394B2 (en) | Analog-to-digital converting circuit | |
| WO2004086628A1 (en) | Encoder circuit and a/d converter circuit | |
| CN111338596B (en) | High dynamic range sound card analog signal data acquisition system and method | |
| CN102571088B (en) | Overflow judging circuit for pipelined analog-to-digital converter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200417 |