High-precision current frequency converter with extended measuring range and use method
By introducing resistive shunt networks and buffers of high-precision op amps into traditional IF current frequency converters, the problems of accuracy and power consumption in traditional technology when dealing with large range input currents are solved, and range expansion and high-precision linear conversion are achieved.
Patent Information
- Application Number
- CN202510216066.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-26
- Publication Date
- 2025-06-13
AI Technical Summary
Traditional IF current frequency converters are difficult to achieve design accuracy when processing input currents with a large range, and require large power consumption, resulting in heat dissipation problems.
The architecture of a resistive shunt network and integrator is adopted. The input current is shuntted through the resistive shunt network, and part of the current flows into the integrator, thereby expanding the range of the input current, and using a high-precision op amp as a buffer to ensure that the integrator is consistent at the non-common end of the quantized charge device.
On the basis of the traditional architecture, the range of the input current is significantly improved, while ensuring high accuracy and high linearity, reducing power consumption and reducing heat dissipation problems.
Smart Images
Figure CN120150706A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of high-precision analog-to-digital conversion technology, and particularly relates to a high-precision current-frequency converter with an extended range and its usage method. Background Art
[0002] The traditional charge-balanced IF current-frequency converter, where I represents current and F represents frequency, as Figure 1 shown, mainly consists of an input current 1, an integrating capacitor 2, an integrator operational amplifier 3, polarity switches 4 and 5, constant current sources 6 and 7, a logic control circuit 8, a frequency output 9, and a reference frequency 10. Its basic principle is that the input current I in charges the capacitor, and at the same time, the internally designed constant current source I ccs periodically charges the capacitor in the reverse direction (controlled by the logic control circuit), and the charging time each time is fixed at T c . Thus, the charge balance of the input and output on the integrating capacitor is achieved within a period of time, obtaining an output signal whose frequency is proportional to the magnitude of the input current, and realizing a linear conversion from the magnitude of the current to the magnitude of the frequency. However, the traditional IF architecture uses an integrator architecture with an operational amplifier and an integrating capacitor, making it difficult to meet the design accuracy requirements for a relatively large input current and requiring relatively high power consumption, posing a challenge to heat dissipation for a fully integrated IF system.
[0003] Based on this, a new technical solution is needed. Summary of the Invention
[0004] In view of this, this application provides a high-precision current-frequency converter with an extended range and its usage method.
[0005] This application provides the following technical solutions:
[0006] A high-precision current-frequency converter with an extended range according to this application includes a resistor shunt network and an integrator. The input end of the resistor shunt network is used to receive the input current, and the output end of the resistor shunt network is connected to the integrator, so that the input current is shunted through the resistor shunt network, and a part of the shunted input current flows into the integrator to extend the input current range.
[0007] Preferably, the resistor shunt network includes a first resistor and a second resistor; the current-frequency converter further includes an input current source, the input current source flows through the input current, the input current source is respectively connected to one end of the first resistor and one end of the second resistor, and the other end of the first resistor is connected to the integrator.
[0008] Preferably, the first resistor and the second resistor are set according to a preset resistance ratio.
[0009] Preferably, the high-precision current-frequency converter further includes a high-precision operational amplifier as a buffer. The other end of the second resistor is connected to the output end and the inverting input end of the high-precision operational amplifier, and the other end of the first resistor is also connected to the non-inverting input end of the high-precision operational amplifier, so that the buffer is placed in the resistor shunt network for clamping the non-common end of the resistor shunt network, and the integrator quantifies the voltage of the non-common end of the charge device to be consistent.
[0010] Preferably, the high-precision operational amplifier uses an operational amplifier with low offset voltage and driving ability.
[0011] Preferably, the integrator includes an integration capacitor and an integrator operational amplifier. The other end of the first resistor is also connected to the inverting input end of the integrator operational amplifier and one end of the integration capacitor. The other end of the integration capacitor is connected to the output end of the integrator operational amplifier, and the non-inverting input end of the integrator operational amplifier is grounded to charge and discharge the integration capacitor.
[0012] Preferably, the high-precision current-frequency converter further includes a logic control module, a frequency output module, a first polarity switch, a second polarity switch, a forward switch constant current source, and a reverse switch constant current source. The other end of the first resistor is also connected to one end of the first polarity switch and one end of the second polarity switch. The other end of the first polarity switch is connected to the forward switch constant current source, and the other end of the second polarity switch is connected to the reverse switch constant current source. The logic control module is connected to control the first polarity switch and the second polarity switch. The other end of the integration capacitor is also connected to the logic control module, and the logic control module is connected to the frequency output module, so that the output of the integrator is processed by the logic control module. The logic control module performs negative feedback control on the first polarity switch and the second polarity switch, and the forward switch constant current source and the reverse switch constant current source perform reverse charge and discharge on the integration capacitor, and the frequency output module generates an output signal with frequency information.
[0013] Preferably, the high-precision current-frequency converter further includes a clock module. The clock module is respectively connected to the logic control module and the frequency output module, so that the clock module generates a standard frequency to provide clocks for the logic control module and the frequency output module.
[0014] According to a method of using a current-frequency converter provided by the present application, applying the high-precision current-frequency converter with an extended range described in any one of the above, including: by increasing a resistor shunt network, the input current is shunted through the resistor shunt network, and a part of the shunted input current flows into the integrator to extend the input current range.
[0015] Preferably, the method of use further includes: by adding a buffer, placing the buffer in the resistor shunt network, clamping the non-common end of the resistor shunt network, and making the voltage of the non-common end of the integrator in the quantization charge device consistent.
[0016] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in this application at least include:
[0017] Based on the traditional architecture, by setting the ratio of the resistance network, the architecture of this application can significantly increase the range of the input current, while still ensuring the high precision and high linearity of the overall system. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0019] Figure 1 Shows the architecture diagram of a traditional charge-balanced IF current-to-frequency converter;
[0020] Figure 2 Shows the architecture diagram of the charge-balanced IF current-to-frequency converter with extended range of this application.
[0021] Reference numerals: 1, input current source; 2, integration capacitor; 3, integrator operational amplifier; 4, first polarity switch; 5, second polarity switch; 6, positive switched constant current source; 7, negative switched constant current source; 8, logic control module; 9, frequency output module; 10, clock module; 11, first resistor; 12, second resistor; 13, high-precision operational amplifier. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0022] The embodiments of this application will be described in detail below with reference to the drawings.
[0023] The following specific examples illustrate the implementation manners of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. This application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.
[0024] It should be noted that the following describes various aspects of embodiments within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on this application, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement an apparatus and / or practice a method. Additionally, this apparatus and / or method can be implemented using other structures and / or functionality in addition to one or more of the aspects set forth herein.
[0025] It should also be noted that the diagrams provided in the following embodiments only illustrate the basic concept of this application schematically. The components shown in the diagrams only relate to those in this application and are not drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.
[0026] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that these examples can be practiced without these specific details.
[0027] As Figure 1 shown, it is a traditional charge-balanced IF current-frequency converter architecture. This architecture mainly consists of an input current 1 passing through an integrator architecture composed of an integration capacitor 2 and an integrator operational amplifier 3 to charge (discharge) the integration capacitor, and at the same time, the output V of the integrator o is processed by a logic control module 8 to perform negative feedback control on polarity switches 4 and 5, and the integration capacitor is reversely charged (discharged) through the switch constant current sources 6 and 7. Through this system, within a certain period of time, an output signal f with frequency information is generated by the logic control module 8 and the frequency output module 9 o1 and f o2 . The clocks of the logic control module and the frequency output module are provided by a clock module 10 that generates a reference frequency f k .
[0028] Based on this, the following describes the technical solutions provided by each embodiment of this application in conjunction with the accompanying drawings.
[0029] An embodiment of this specification proposes a high-precision current-frequency converter with an extended range. As Figure 2 shown, it includes a resistor shunt network and an integrator. The input end of the resistor shunt network is used to receive an input current, and the output end of the resistor shunt network is connected to the integrator so that the input current is shunted through the resistor shunt network, and a part of the shunted input current flows into the integrator to extend the input current range.
[0030] In one embodiment, the resistor shunt network includes a first resistor 11 and a second resistor 12; the current frequency converter further includes an input current source 1. The input current source 1 passes through an input current. The input current source 1 is respectively connected to one end of the first resistor 11 and one end of the second resistor 12. The other end of the first resistor 11 is connected to an integrator.
[0031] In one embodiment, the first resistor 11 and the second resistor 12 are set according to a preset resistance ratio.
[0032] In one embodiment, the high-precision current frequency converter further includes a high-precision operational amplifier 13 as a buffer. The other end of the second resistor 12 is connected to the output end and the inverting input end of the high-precision operational amplifier 13. The other end of the first resistor 11 is also connected to the non-inverting input end of the high-precision operational amplifier 13, so that the buffer is placed in the resistor shunt network to clamp the non-common end of the resistor shunt network, and the voltage of the non-common end of the integrating capacitor device is made consistent.
[0033] In one embodiment, the high-precision operational amplifier 13 uses an operational amplifier with low offset voltage and driving ability.
[0034] In one embodiment, the integrator includes an integrating capacitor 2 and an integrator operational amplifier 3. The other end of the first resistor 11 is also connected to the inverting input end of the integrator operational amplifier 3 and one end of the integrating capacitor 2. The other end of the integrating capacitor 2 is connected to the output end of the integrator operational amplifier 3. The non-inverting input end of the integrator operational amplifier 3 is grounded to charge and discharge the integrating capacitor 2.
[0035] In one embodiment, the high-precision current frequency converter further includes a logic control module 8, a frequency output module 9, a first polarity switch 4, a second polarity switch 5, a forward switch constant current source 6, and a negative switch constant current source 7. The other end of the first resistor 11 is also connected to one end of the first polarity switch 4 and one end of the second polarity switch 5. The other end of the first polarity switch 4 is connected to the forward switch constant current source 6. The other end of the second polarity switch 5 is connected to the negative switch constant current source 7. The logic control module 8 is controlled to connect the first polarity switch 4 and the second polarity switch 5. The other end of the integrating capacitor 2 is also connected to the logic control module 8. The logic control module 8 is connected to the frequency output module 9, so that the output of the integrator is processed by the logic control module 8. The logic control module 8 performs negative feedback control on the first polarity switch 4 and the second polarity switch 5. The forward switch constant current source 6 and the negative switch constant current source 7 perform reverse charge and discharge on the integrating capacitor 2. The frequency output module 9 generates an output signal with frequency information.
[0036] In one embodiment, the high-precision current frequency converter further includes a clock module 10, and the clock module 10 is respectively connected to the logic control module 8 and the frequency output module 9, so that the clock module 10 generates a standard frequency to provide clocks for the logic control module 8 and the frequency output module 9.
[0037] This application is a new charge-balanced IF current frequency converter architecture. Based on the traditional full-scale operational amplifier + integrating capacitor 2 integrator architecture, the extended-range charge-balanced IF current frequency converter architecture of this application is as Figure 2 shown. Its core idea is to add a high-precision operational amplifier 13 as a follower and a shunt resistor network R0 / R1 on the basis of the traditional architecture. At a certain resistance ratio, on the existing-range integrator architecture, only part of the current flows into the integrator through the form of shunting by the resistor network, and finally the input current range is expanded. For example, the resistance ratio is set as follows: the original input current range of the architecture is 20 mA. When the R0 / R1 resistance ratio is set to 1 / 4, after shunting by the resistor network, the current flowing into the integrator is still 20 mA, and the current flowing into the buffer is 80 mA. Then the total input current range will be expanded from 20 mA to 100 mA.
[0038] As Figure 2 shown, it is the charge-balanced IF current frequency converter architecture for expanding the range. This architecture mainly shunts the input current through the resistor network R 0 and R 1 . The buffer G m2 clamps the non-common ends V x and V y of the resistor network to ensure the consistency of the voltage across the charge quantization device of the integrator in the system. The shunted current I R1 is input into the integrator architecture composed of the integrating capacitor 2 and the integrator operational amplifier 3 to charge (discharge) the integrating capacitor 2. At the same time, the output V o of the integrator is processed by the logic control module 8 to perform negative feedback control on the polarity switch, and the integrating capacitor 2 is reversely charged (discharged) by means of a switched constant current source. Through this system, within a certain period of time, output signals f o1 and f o2 with frequency information are generated by the logic control module 8 and the frequency output module 9. The clocks of the logic control module 8 and the frequency output module 9 are provided by the clock module 10 that generates the standard frequency f k .
[0039] The embodiments of this specification also provide a method for using a current frequency converter, which applies the high-precision current frequency converter with an extended range in any of the above embodiments, including: by adding a resistor shunt network, the input current is shunted through the resistor shunt network, and a part of the shunted input current flows into the integrator to extend the input current range.
[0040] In one embodiment, the method for using further includes: by adding a buffer, placing the buffer in the resistor shunt network, clamping the non-common end of the resistor shunt network, and making the voltage at the non-common end of the quantization charge device of the integrator consistent.
[0041] Based on the architecture of the traditional IF current frequency converter, this application adds a resistor shunt network and a buffer, which can expand the input current range on the original basis while ensuring high precision and linearity requirements, so as to increase the application scenarios of the IF current frequency converter.
[0042] The architecture of this application can, on the traditional basis, significantly increase the input current range only by setting the ratio of the resistor network, while still ensuring the high precision and high linearity of the overall system. During quantization, the voltage V at the negative input terminal of the integrator x will change continuously. Therefore, for the type of operational amplifier of the G m2 buffer, this architecture adopts a high-precision operational amplifier 13 with a certain driving ability and low offset voltage, which ensures the consistency of the voltages V x and V y at the non-common ends of the resistors R0 and R1, thus ensuring the accuracy of current shunting and greatly improving the linearity and accuracy of different input currents under the extended range.
[0043] In this specification, the same or similar parts among the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the embodiments described later, the description is relatively simple, and the relevant parts can be referred to the partial description of the foregoing embodiments.
[0044] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.
Claims
1. A high-precision current-to-frequency converter with an extended range, characterized in that: It includes a resistor shunt network and an integrator. The input end of the resistor shunt network is used to receive input current, and the output end of the resistor shunt network is connected to the integrator, so that the input current is shunted through the resistor shunt network, and part of the shunted input current flows into the integrator to expand the input current range.
2. The high-precision current-to-frequency converter with an extended range according to claim 1, characterized in that: The resistor shunt network includes a first resistor and a second resistor; the current-frequency converter also includes an input current source, through which the input current flows, and the input current source is respectively connected to one end of the first resistor and one end of the second resistor, and the other end of the first resistor is connected to the integrator.
3. The high-precision current-to-frequency converter with an extended range according to claim 2, characterized in that: The first resistor and the second resistor are set according to a preset resistance ratio.
4. The high-precision current-to-frequency converter with an extended range according to claim 2, characterized in that: The high-precision current-frequency converter also includes a high-precision operational amplifier as a buffer. The other end of the second resistor is connected to the output end and the reverse input end of the high-precision operational amplifier. The other end of the first resistor is also connected to the in-phase input end of the high-precision operational amplifier, so that the buffer is placed in the resistor shunt network and is used to clamp the non-common end of the resistor shunt network. The integrator has consistent voltage at the non-common end of the quantized charge device.
5. The high-precision current-to-frequency converter with an extended range according to claim 4, characterized in that: The high-precision operational amplifier adopts an operational amplifier with low offset voltage and driving capability.
6. The high-precision current-to-frequency converter with an extended range according to any one of claims 2 to 5, characterized in that: The integrator includes an integrating capacitor and an integrator operational amplifier. The other end of the first resistor is also connected to the inverting input end of the integrator operational amplifier and one end of the integrating capacitor. The other end of the integrating capacitor is connected to the output end of the integrator operational amplifier. The in-phase input end of the integrator operational amplifier is grounded to charge and discharge the integrating capacitor.
7. The high-precision current-to-frequency converter with an extended range according to claim 6, characterized in that: The high-precision current-frequency converter also includes a logic control module, a frequency output module, a first polarity switch, a second polarity switch, a positive switch constant current source, and a negative switch constant current source. The other end of the first resistor is also connected to one end of the first polarity switch and one end of the second polarity switch. The other end of the first polarity switch is connected to the positive switch constant current source, and the other end of the second polarity switch is connected to the negative switch constant current source. The logic control module controls the connection between the first polarity switch and the second polarity switch. The other end of the integral capacitor is also connected to the logic control module. The logic control module is connected to the frequency output module so that the integrator output is processed by the logic control module. The logic control module performs negative feedback control on the first polarity switch and the second polarity switch. The positive switch constant current source and the negative switch constant current source reversely charge and discharge the integral capacitor. The frequency output module generates an output signal with frequency information.
8. The high-precision current-to-frequency converter with an extended range according to claim 7, characterized in that: The high-precision current-frequency converter also includes a clock module, which is connected to the logic control module and the frequency output module respectively, so that the clock module generates a standard frequency to provide clocks for the logic control module and the frequency output module.
9. A method for using a current-to-frequency converter, characterized in that: The high-precision current-frequency converter with extended range described in any one of claims 1 to 8 comprises: adding a resistor shunt network, the input current is shunted through the resistor shunt network, and the shunted part of the input current flows into the integrator to expand the input current range.
10. The method for using the current-to-frequency converter according to claim 9, characterized in that: The method of use also includes: adding a buffer, placing the buffer in a resistor shunt network, clamping the non-common end of the resistor shunt network, and making the integrator consistent with the voltage at the non-common end of the quantized charge device.