CN220067405U - Digital-to-analog conversion device and signal processing apparatus - Google Patents
Digital-to-analog conversion device and signal processing apparatus Download PDFInfo
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- CN220067405U CN220067405U CN202321012834.5U CN202321012834U CN220067405U CN 220067405 U CN220067405 U CN 220067405U CN 202321012834 U CN202321012834 U CN 202321012834U CN 220067405 U CN220067405 U CN 220067405U
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Abstract
The utility model relates to a digital-to-analog conversion device and a signal processing apparatus, the digital-to-analog conversion device comprises: two or more digital-to-analog converters; the proportional amplifying circuit comprises a proportional resistor module and a feedback amplifier, wherein the proportional resistor module comprises a proportional resistor; the number of the proportional resistors is the same as that of the digital-to-analog converters, the resistance value ratio between at least two proportional resistors is a set positive integer, and each digital-to-analog converter is connected with the feedback amplifier through a corresponding proportional resistor. The high-precision DAC can be realized by adopting the low-precision DAC to combine with the proportional amplifying circuit to obtain the high-precision DAC, so that the cost is reduced.
Description
Technical Field
The present utility model relates to the field of digital-to-analog conversion technology, and in particular, to a digital-to-analog conversion device and a signal processing apparatus.
Background
A DAC (Digital to Analog Converter, digital-to-analog converter), also known as a D/a converter, is a converter that converts a discrete signal in the form of a binary digital quantity into an analog quantity referenced to a standard quantity (or reference quantity). The high-precision DAC plays an extremely important role in the high-resolution digital-to-analog conversion process, and is widely applied to automatic test equipment, precise instruments, calibration instruments, medical electronic equipment and other application fields. But the high-precision DAC chip is high in price, and the cost of the product can be greatly increased because the technology is blocked and is difficult to buy abroad, so that the competitiveness of the product is seriously affected. Therefore, how to realize a high-precision DAC with a low-precision DAC to reduce the cost is a problem to be solved.
Disclosure of Invention
In view of the foregoing, it is necessary to provide a digital-to-analog conversion apparatus and a signal processing device that realize a high-precision DAC with a low-precision DAC to reduce costs.
A digital to analog conversion apparatus, comprising:
two or more digital-to-analog converters;
the proportional amplifying circuit comprises a proportional resistor module and a feedback amplifier, wherein the proportional resistor module comprises a proportional resistor;
the number of the proportional resistors is the same as that of the digital-to-analog converters, the resistance value ratio between at least two proportional resistors is a set positive integer, and each digital-to-analog converter is connected with the feedback amplifier through a corresponding proportional resistor.
In one embodiment, the digital-to-analog converter comprises a master digital-to-analog converter and a slave digital-to-analog converter, the proportional resistor comprises a master proportional resistor and a slave proportional resistor, and the resistance value ratio of the slave proportional resistor to the master proportional resistor is a set positive integer; the master digital-to-analog converter is connected with the feedback amplifier through the master proportional resistor, and the slave digital-to-analog converter is connected with the feedback amplifier through the slave proportional resistor.
In one embodiment, the master digital-to-analog converter and the slave digital-to-analog converter are digital-to-analog converters with different precision.
In one embodiment, the master digital-to-analog converter and the slave digital-to-analog converter are digital-to-analog converters with the same output voltage range.
In one embodiment, the feedback amplifier comprises an operational amplifier and a feedback module, wherein the operational amplifier is connected with each proportional resistor and the feedback module.
In one embodiment, the operational amplifier comprises an adder and an amplifying unit, the adder is connected with each proportional resistor and the amplifying unit, and the feedback module is connected with the amplifying unit and the adder.
In one embodiment, the feedback module is connected to the inverting input of the operational amplifier and the output of the operational amplifier.
In one embodiment, the digital-to-analog conversion device further comprises a processor for performing numerical distribution on the digital-to-analog converter according to the resistance value ratio between the proportional resistors.
In one embodiment, the feedback module is a feedback resistor, and the resistance value of the feedback resistor is the same as the resistance value of the main proportional resistor in the proportional resistor module.
A signal processing apparatus comprises the digital-to-analog conversion device.
According to the digital-to-analog conversion device and the signal processing equipment, the proportional resistors are respectively configured for the digital-to-analog converters, the resistance value ratio between at least two proportional resistors is a set positive integer, and the digital-to-analog conversion device with higher precision can be obtained by combining the digital-to-analog converter with lower precision with the proportional amplifying circuit, so that the high-precision DAC is realized by the DAC with lower precision, and the cost is reduced.
Drawings
FIG. 1 is a block diagram of a digital to analog conversion apparatus in one embodiment;
fig. 2 is a schematic diagram of a digital-to-analog conversion apparatus according to an embodiment.
Reference numerals illustrate: 100. a digital-to-analog converter; 110. a main digital-to-analog converter; 120. a slave digital-to-analog converter; 200. a proportional amplifying circuit; 210. a proportional resistance module; 220. a feedback amplifier; 222. an operational amplifier; 224. a feedback module; 300. a processor.
Detailed Description
The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model.
It will be understood that the terms first, second, etc. as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the utility model. Both the first resistor and the second resistor are resistors, but they are not the same resistor.
It is to be understood that in the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", etc., if the connected circuits, modules, units, etc., have electrical or data transfer between them.
As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and the like, specify the presence of stated features, integers, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, operations, elements, components, or groups thereof.
In one embodiment, as shown in fig. 1, a digital-to-analog conversion apparatus is provided, including a digital-to-analog converter 100 and a proportional amplifying circuit 200. The digital-to-analog converter 100 has two or more digital-to-analog converters, and the proportional amplifying circuit 200 includes a proportional resistor module 210 and a feedback amplifier 220, wherein the proportional resistor module 210 includes a proportional resistor. The number of the proportional resistors is the same as that of the digital-to-analog converters 100, and the resistance ratio between at least two proportional resistors is a set positive integer, and each digital-to-analog converter 100 is connected to the feedback amplifier 220 through a corresponding proportional resistor.
The number of digital-to-analog converters 100 may be two, three or more, and each digital-to-analog converter 100 is connected to the feedback amplifier 220 through a corresponding proportional resistor. The arrangement mode of the resistance value ratio among the proportional resistors is not unique, and the resistance value ratio among all the proportional resistors can be a set positive integer; the resistance values of the partial proportional resistors may be the same, and the resistance value ratio between the partial proportional resistors may be a positive integer. The ratio of the resistance values between the proportional resistors is set to be a positive integer, so that weight distribution of each digital-to-analog converter 100 is facilitated, calculation is easier, and operation is simple, convenient and quick. The weights of the respective digital-to-analog converters 100 are determined in accordance with the resistance value ratio between the proportional resistors for numerical value distribution, thereby changing the accuracy of the digital-to-analog converters 100. Taking two digital-to-analog converters 100 as an example, the weight distribution can be changed by changing the resistance ratio of the two proportional resistors, so that the precision is changed, and the structure is simple and the cost is low.
In one embodiment, as shown in fig. 2, the digital-to-analog converter 100 includes a master digital-to-analog converter 110 and a slave digital-to-analog converter 120, the proportional resistors include a master proportional resistor R1 and a slave proportional resistor R2, and the resistance value ratio of the slave proportional resistor R2 to the master proportional resistor R1 is a set positive integer; the master digital-to-analog converter 110 is connected to the feedback amplifier 220 through a master proportional resistor R1, and the slave digital-to-analog converter 120 is connected to the feedback amplifier 220 through a slave proportional resistor R2. The specific value of the positive integer K is set, and the positive integer K can be set according to actual needs. If the resistance value of the master proportional resistor R1 is R, the resistance value of the slave proportional resistor R2 is k×r. The main digital-to-analog converter 110 is connected with the feedback amplifier 220 through the main proportional resistor R1, the weight is 1, the slave digital-to-analog converter 120 is connected with the feedback amplifier 220 through the slave proportional resistor R2, the weight is 1/K, and the feedback amplifier 220 sums up through the superposition theorem to obtain the output Vout of the digital-to-analog conversion device, namely the output of the high-precision DAC.
The accuracy of the master digital-to-analog converter 110 and the slave digital-to-analog converter 120 may be the same or different; the output voltage ranges of the master digital-to-analog converter 110 and the slave digital-to-analog converter 120 may be the same or different. In one embodiment, the master digital-to-analog converter 110 and the slave digital-to-analog converter 120 are digital-to-analog converters with different precision, so that weight distribution and precision adjustment are facilitated. Further, the master digital-to-analog converter 110 and the slave digital-to-analog converter 120 are digital-to-analog converters with the same output voltage range, so that weight distribution and precision adjustment are facilitated.
The specific configuration of feedback amplifier 220 is not exclusive, and in one embodiment, with continued reference to FIG. 2, feedback amplifier 220 includes an operational amplifier 222 and a feedback module 224, with operational amplifier 222 coupled to each of the proportional resistors and feedback module 224. The operational amplifier 222 includes an adder and an amplifying unit (with an open loop gain of Aol), the adder is connected to each proportional resistor and the amplifying unit, and the feedback module is connected to the amplifying unit and the adder. Specifically, each proportional resistor may be connected to the non-inverting input terminal of the operational amplifier 222 or may be connected to the inverting input terminal of the operational amplifier 222. In this embodiment, the non-inverting input terminal of the operational amplifier 222 is connected to each proportional resistor, and the feedback module 224 is connected to the inverting input terminal of the operational amplifier 222 and the output terminal of the operational amplifier 222. Also taking the example where the proportional resistors include a master proportional resistor R1 and a slave proportional resistor R2, the master digital-to-analog converter 110 is connected to the non-inverting input of the operational amplifier 222 through the master proportional resistor R1, and the slave digital-to-analog converter 120 is connected to the non-inverting input of the operational amplifier 222 through the slave proportional resistor R2. The feedback module 224 is disposed between the inverting input and the output of the operational amplifier 222, and performs voltage superposition through the inverting input of the operational amplifier 222.
The specific configuration of the feedback module 224 is also not exclusive, and in one embodiment, the feedback module 224 is a feedback resistor. The resistance value of the feedback resistor is the same as the resistance value of the main proportional resistor R1 in the proportional resistor module 210. The resistance value of the feedback resistor is set to be the same as that of the main proportional resistor R1, so that the feedback amplifier 220 can conveniently perform amplification proportion adjustment.
The output voltage ranges of the master digital to analog converter 110 and the slave digital to analog converter 120 can be determined by programming, and then different weights can be provided by the configuration of the operational amplifier 222 and the proportional resistance module 210, and finally the final output is superimposed. For example, the master digital to analog converter 110 selects an M-bit DAC with a weight of 1, the slave digital to analog converter 120 selects an N-bit DAC with a weight of 1/K, and the slave digital to analog converter 120 increases the log2 (K) bit precision. When n+log2 (K) > M is satisfied, the precision a=n+log2 (K) of the digital-to-analog conversion device. When n+log2 (K). Ltoreq.M, the precision of the digital-to-analog conversion device is A=M.
Furthermore, in one embodiment, the digital-to-analog converter device further comprises a processor 300, and the processor 300 is configured to perform numerical assignment to the digital-to-analog converter 100 according to a resistance value ratio between the proportional resistors. The specific type of the processor 300 is not unique, and may be an FPGA (Field Programmable Gate Array ), a CPU (Central Processing Unit, central processing unit), or an MCU (Micro Control Unit ), etc.
Specifically, the processor 300 controls the outputs of the master digital-to-analog converter 110 and the slave digital-to-analog converter 120, the operational amplifier 222 and the feedback module 224 form the feedback amplifier 220, and the proportional resistance module 210 and the feedback amplifier 220 form the proportional amplifying circuit 200. The low precision master digital to analog converter 110 and the slave digital to analog converter 120 are inputs to the proportional amplifying circuit, and the output voltage ranges are the same. An M-bit DAC as the main digital-to-analog converter 110, added to the proportional amplifying circuit 200 through the main proportional resistor R1, and weighted 1; an N-bit DAC is added to the scaling circuit as a slave digital-to-analog converter 120 by a slave scaling resistor R2, weighting 1/K.
Taking the output of the master dac 110 and the output of the slave dac 120 as examples, the output of the measurement range of ±x (V) is selected, the weight of the master dac 110 is 1,1LSB (Least Significant Bit ) = 2*x/2^M (V); the slave digital-to-analog converter 120 has a weight of 1/K, and outputs a range of + -x/K (V), 1 LSB= 2*x/2≡N/K (V). That is, when the processor assigns the desired output value y, the processor first rounds down y/(x/k), and then marks a as a= [ int (y/(x/k)) ], assigns a (x/k) to the master digital-to-analog converter 110, and y-a (x/k) to the slave digital-to-analog converter 120.
The equivalent output of the main digital-to-analog converter 110 and the output voltage of the sub digital-to-analog converter 120 after being superimposed is referred to as add_dac for short. The processor 300 performs the following steps in the DAC code value processing:
step1: the ADD_DAC value is divided by x/K, rounded down, denoted as a, and converted to a code value in LSB units and then applied to the main DAC 110.
Step2: the add_dac subtracts a x/K, denoted b, converts the value into a code value in LSB units, and gives the code value to the slave digital-to-analog converter 120.
The DAC has differential nonlinearity, the main DAC 110 has a relatively large weight, the code value deviates from the ideal output voltage by a relatively large amount, but the output voltage corresponding to the determined code value is not good, and the determined output voltage can be known through a lookup table. Thus, the primary digital-to-analog converter 110 removes the effects of DNL (Differential Nonlinearity ) and INL (Integral Nonlinearity, integral nonlinearity) by looking up the table output. Therefore, the main limitation of DNL and INL is that the DNL of the slave digital-to-analog converter 120 can be selected to meet the actual DNL requirement by selecting an appropriate slave digital-to-analog converter 120.
In the case of numerical distribution, the main dac 110 is output in a piecewise dotted manner, and the sub-dac 120 is used to divide 1LSB of the main dac 110 more finely. The slave digital to analog converter 120 essentially divides the 1LSB into K equal parts for smaller set resolution. Thus, the ADD_DAC has a resolution equivalent to the resolution of the DAC 120 from the DC effect of 2*x/2≡N/K (V). The equivalent output noise of the add_dac is the root mean square of the noise output from the master digital-to-analog converter 110 and the slave digital-to-analog converter 120, where the output from the slave digital-to-analog converter 120 is attenuated by a factor K.
According to the digital-to-analog conversion device provided by the utility model, 2 paths of low-precision DAC outputs are combined into the proportional amplifying circuit 200 according to a certain weight, so that the DAC output with higher direct-current precision is realized, the used circuit is simpler, the cost is low, the implementation is easy, and the high direct-current precision is realized under high-density application.
In an embodiment, there is also provided a signal processing apparatus including the digital-to-analog conversion device described above.
In one embodiment, a test system is also provided, including the signal processing device described above.
The digital-to-analog conversion device, the signal processing device and the test system are respectively configured with a proportional resistor for each digital-to-analog converter 100, and the resistance value ratio between at least two proportional resistors is a set positive integer, so that the digital-to-analog conversion device with higher precision can be obtained by combining the digital-to-analog converter with lower precision with the proportional amplifying circuit 200, and the high-precision DAC can be realized with the low-precision DAC to reduce the cost.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the utility model, which are described in detail and are not to be construed as limiting the scope of the utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of protection of the present utility model is to be determined by the appended claims.
Claims (10)
1. A digital to analog conversion apparatus, comprising:
two or more digital-to-analog converters;
the proportional amplifying circuit comprises a proportional resistor module and a feedback amplifier, wherein the proportional resistor module comprises a proportional resistor;
the number of the proportional resistors is the same as that of the digital-to-analog converters, the resistance value ratio between at least two proportional resistors is a set positive integer, and each digital-to-analog converter is connected with the feedback amplifier through a corresponding proportional resistor.
2. The digital-to-analog conversion apparatus according to claim 1, wherein the digital-to-analog converter includes a master digital-to-analog converter and a slave digital-to-analog converter, the proportional resistor includes a master proportional resistor and a slave proportional resistor, and a resistance value ratio of the slave proportional resistor to the master proportional resistor is a set positive integer; the master digital-to-analog converter is connected with the feedback amplifier through the master proportional resistor, and the slave digital-to-analog converter is connected with the feedback amplifier through the slave proportional resistor.
3. The digital-to-analog conversion apparatus according to claim 2, wherein the master digital-to-analog converter and the slave digital-to-analog converter are digital-to-analog converters having different accuracies.
4. The digital-to-analog conversion apparatus according to claim 2, wherein the master digital-to-analog converter and the slave digital-to-analog converter are digital-to-analog converters having the same output voltage range.
5. The digital to analog conversion apparatus of claim 1, wherein said feedback amplifier comprises an operational amplifier and a feedback module, said operational amplifier being connected to each of said proportional resistors and said feedback module.
6. The digital to analog conversion apparatus according to claim 5, wherein said operational amplifier comprises an adder and an amplifying unit, said adder is connected to each of said proportional resistors and said amplifying unit, and said feedback module is connected to said amplifying unit and said adder.
7. The digital to analog conversion apparatus of claim 5, wherein said feedback module is connected to an inverting input of said operational amplifier and an output of said operational amplifier.
8. The digital to analog conversion apparatus of claim 5, wherein said feedback module is a feedback resistor having a same resistance as a main proportional resistor of said proportional resistor module.
9. The digital to analog conversion apparatus according to any one of claims 1 to 8, further comprising a processor for numerical distribution of the digital to analog converter according to a resistance value ratio between proportional resistors.
10. A signal processing apparatus comprising a digital-to-analogue conversion device as claimed in any one of claims 1 to 9.
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| CN202321012834.5U CN220067405U (en) | 2023-04-26 | 2023-04-26 | Digital-to-analog conversion device and signal processing apparatus |
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