Programmable gain amplifier and signal measurement system
By designing independent buffer, gain, and output amplification modules, and utilizing feedback circuits and switchable switches to achieve dynamic gain adjustment, the problems of high noise, large size, and difficulty in meeting testing requirements in existing technologies are solved, thereby improving testing accuracy and performance.
Patent Information
- Application Number
- CN202423208293.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2026-01-02
- Estimated Expiration
- 2034-12-25
AI Technical Summary
When existing programmable gain amplifiers are implemented through chip integration, they suffer from high noise, are unsuitable for low-frequency signal testing, cannot simultaneously meet the testing requirements for frequency, noise, harmonic distortion, and impedance, and have a large product size.
Design a programmable gain amplifier that includes a buffer module, a gain module, and an output amplification module. By setting at least two feedback circuits and a switchable switch, the gain can be dynamically adjusted, and each module can be adjusted independently to meet different test requirements.
It achieves dynamic adjustment of gain, simplifies operation, reduces product complexity and size, and meets testing requirements such as frequency, noise, harmonic distortion, and impedance, thereby improving testing accuracy and performance.
Smart Images
Figure CN223758250U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of semiconductor test, especially to a programmable gain amplifier and signal measurement system. BACKGROUND
[0002] In the field of semiconductor chip testing, a small signal measurement system is usually used to test the performance of a DAC chip, and a programmable gain amplifier is usually provided to adjust different amplification factors in order to meet different amplitudes of input signals.
[0003] The current programmable gain amplifier is mainly realized by chip integration, provides an interface of digital programmable gain, and can adjust the gain of the amplifier through the SPI or digital control logic register writing mode. However, this mode has the problems of large chip noise, unsuitability for low-frequency signal testing, difficulty in simultaneously meeting different testing requirements of frequency, noise, harmonic distortion, impedance, etc. for the same chip, and large product size. SUMMARY
[0004] The utility model aims at least to solve one of the technical problems existing in the prior art. For this purpose, the utility model provides a programmable gain amplifier and signal measurement system.
[0005] The first aspect embodiment of the utility model provides a programmable gain amplifier, which comprises: a buffer module, the buffer module is used for receiving an input signal; a gain module, one end of the gain module is connected with the input end of the buffer module, and the other end is connected with the output end of the buffer module; an output amplification module, the input end of the output amplification module is connected with the other end of the gain module and the output end of the buffer module respectively, and the output end is used for outputting a corresponding output signal; wherein the gain module comprises: at least two feedback circuits, one end of the feedback circuit is connected with the output end of the buffer module; at least one switchable switch, one end of the switchable switch is connected with the input end of the buffer module, and the other end is connected with the other end of the feedback circuit, and the switchable switch is used for communicating with one of the feedback circuits.
[0006] The programmable gain amplifier provided by the embodiment of the utility model has at least the following beneficial effects: the gain module is arranged to enable the amplifier to output different gain sizes according to different test requirements, thereby realizing dynamic adjustment of the gain.
[0007] In some embodiments of the utility model, the feedback circuit is used for providing different sizes of gain, and the at least two feedback circuits are one sampling feedback circuit and multiple gain feedback circuits.
[0008] In some embodiments of the utility model, the input signal is a single-ended signal, and the buffer module comprises two operational amplifiers, one end of the operational amplifier is connected with the gain module, the output end is connected with the other end of the gain module and the input end of the output amplification module, the positive input end of one of the operational amplifiers is connected with the input signal, and the positive input end of the other operational amplifier is grounded.
[0009] In some embodiments of the utility model, the input signal is a differential signal, comprising a first differential signal and a second differential signal, and the buffer module comprises two operational amplifiers, one end of the operational amplifier is connected with the gain module, the output end is connected with the other end of the gain module and the input end of the output amplification module, the positive input end of one of the operational amplifiers is connected with the first differential signal, and the positive input end of the other operational amplifier is connected with the second differential signal.
[0010] In some embodiments of the utility model, the buffer module further comprises two compensation circuits, one end of the two compensation circuits is respectively connected with the negative input end of the two operational amplifiers, and the other end is respectively connected with the output end of the two operational amplifiers.
[0011] In some embodiments of the utility model, the compensation circuit comprises a first switch, one end of the first switch is connected with the output end of the operational amplifier, a first capacitor, the positive pole of the first capacitor is connected with the other end of the first switch, and the negative pole of the first capacitor is connected with the negative input end of the operational amplifier, wherein the first switch is used for opening or closing according to the gain size.
[0012] In some embodiments of the utility model, the output amplification module includes: two gain resistors, a differential amplifier, the positive and negative input ends of differential amplifier are connected with the other end of gain module and the output end of buffer module through gain resistor respectively, two feedback resistors, the input end and output end of differential amplifier are connected with both ends of feedback resistor respectively.
[0013] In some embodiments of the utility model, the output amplification module further includes: a bandwidth adjustment circuit, the input end and output end of differential amplifier are connected with both ends of bandwidth adjustment circuit respectively.
[0014] In some embodiments of the utility model, the bandwidth adjustment circuit includes: a second switch, one end of second switch is connected with the output end of differential amplifier, a second capacitor, one end of second capacitor is connected with the input end of differential amplifier, and the other end is connected with the other end of second switch.
[0015] The second aspect embodiment of the utility model provides a kind of test system, comprising: the programmable gain amplifier of the first aspect embodiment of the utility model as above.
[0016] According to the signal measurement system of the utility model embodiment, at least has following technical effects: by setting the programmable gain amplifier of the utility model, the gain demand of different input signals can be met, and signal can be amplified to approach full scale of analog-digital converter, so that the best test precision and test performance can be achieved.
[0017] Additional aspects and advantages of the utility model will be partially given in the following description, some will become obvious from the following description, or be understood by the practice of the utility model. BRIEF DESCRIPTION OF DRAWINGS
[0018] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or related technologies, the drawings needed to be used in the description of the embodiments of the utility model or related technologies will be briefly introduced as follows, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other related drawings can be obtained without creative labor on the premise.
[0019] Figure 1 It is the connection schematic diagram of programmable gain amplifier of the utility model embodiment;
[0020] Figure 2 It is the structure schematic diagram of gain module 200 in programmable gain amplifier of the utility model embodiment;
[0021] Figure 3The utility model discloses an electric circuit schematic diagram of programmable gain amplifier.
[0022] Figure 4 Another electric circuit schematic diagram of programmable gain amplifier of the utility model embodiment.
[0023] Reference signs:
[0024] Buffer module 100, operational amplifier 110, compensation circuit 120, first switch S3, first capacitor C1, gain module 200, feedback circuit 210, sampling feedback circuit 211, gain feedback circuit 212, switchable switch 220, output amplification module 300, gain resistor R1, differential amplifier 310, feedback resistor R2, bandwidth adjustment circuit 340, second switch S4, second capacitor C2. DETAILED DESCRIPTION
[0025] The embodiments of the utility model are described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the utility model, and cannot be understood as limiting the utility model.
[0026] In the description of the present application, if the first, second, only can distinguish technical features for the purpose, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of indicated technical features.
[0027] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable way.
[0028] The following refers to Figure 1 The programmable gain amplifier according to the embodiments of the utility model is described below.
[0029] As Figure 1As shown, the programmable gain amplifier comprises a buffer module 100, a gain module 200 and an output amplification module 300, the buffer module 100 is used for receiving an input signal, one end of the gain module 200 is connected with the input end of the buffer module 100, the other end is connected with the output end of the buffer module 100, the input end of the output amplification module 300 is connected with the other end of the gain module 200 and the output end of the buffer module 100 respectively, and the output end is used for outputting a corresponding output signal; wherein the gain module 200 comprises at least two feedback circuits 210 and at least one switchable switch 220, one end of the feedback circuit 210 is connected with the output end of the buffer module 100, one end of the switchable switch 220 is connected with the input end of the buffer module 100, and the other end is connected with the other end of the feedback circuit 210, and the switchable switch 220 is used for being communicated with one of the feedback circuits 210.
[0030] In the prior art, the gain is usually adjusted by a chip integration scheme, so that input signals of different amplitudes can meet the range requirements of the analog-to-digital converter, but by this chip integration method, there are still problems such as large noise and unsuitable for low-frequency signal test, which is difficult to meet the test requirements of testers. Therefore, the utility model provides a new programmable gain amplifier, which comprises a buffer module 100, a gain module 200 and an output amplification module 300. The buffer module 100 is used for receiving an external input signal and processing the input signal, ensuring the stability of the input signal and avoiding distortion of the input signal, which affects the quality of the final output of the programmable gain amplifier. One end of the gain module 200 is connected with the input end of the buffer module 100, and the other end is connected with the output end of the buffer module 100, wherein the gain module 200 comprises at least two feedback circuits 210 and at least one switchable switch 220, the feedback circuit 210 and the switchable switch 220 are connected, the switchable switch 220 is used for controlling the on-off of the feedback circuit 210, so that one of the feedback circuits 210 is connected to the circuit, thereby controlling the output gain size of the programmable gain amplifier. The output amplification module 300 outputs the input signal processed by the buffer module 100 and the gain module 200 to obtain an output signal with a suitable amplification factor.
[0031] The programmable gain amplifier provided by the embodiment of the utility model has at least the following beneficial effects: the gain module 200 is arranged to enable the amplifier to output different gain sizes according to different test requirements, thereby realizing dynamic adjustment of the gain.
[0032] In some embodiments of the utility model, reference is made to Figure 1 and Figure 2 The feedback circuit 210 is used for providing different sizes of gain, and the at least two feedback circuits 210 are one sampling feedback circuit 211 and multiple gain feedback circuits 212.
[0033] Specifically, taking Figure 1 and Figure 2 as examples, the gain module 200 of the programmable gain amplifier comprises four feedback circuits 210 and two switchable switches 220, each feedback circuit 210 provides different sizes of gain for the programmable gain amplifier, and therefore the output gain of the programmable gain amplifier can be controlled by controlling the conduction of different feedback circuits 210.
[0034] The two switchable switches 220 are single-pole four-throw switches, which are switch S1 and switch S2 in the figure, and the two switchable switches 220 can be controlled by external digital logic signals, and different feedback circuits 210 are turned on according to different digital logic signals. The four feedback circuits 210 are one sampling feedback circuit 211 and three gain feedback circuits 212, wherein the sampling feedback circuit 211 comprises two resistors Rf1, one end of the two resistors Rf1 is connected with the switch S1 and the switch S2 respectively, and the other end is connected with the output end of the buffer module 100; the gain feedback circuit 212 is composed of three resistors, taking one of the gain feedback circuits 212 as an example, comprising two resistors Rf2 and one resistor Rg2, one end of the two resistors Rf2 is connected with the switch S1 and the switch S2 respectively, and the other end is connected with the output end of the buffer module 100, and the other end of the two resistors Rf2 is connected through the resistor Rg2, and the composition and connection of the other two gain feedback circuits 212 are the same as that of the gain feedback circuit 212, which will not be described here.
[0035] The gain sizes provided by each feedback circuit 210 are different, and the calculation formula of the gain size is as follows: , where n is the resistance mark. Because no resistance Rg is set in the sampling feedback circuit 211, the gain provided is 1, that is, the signal output by the output amplification module 300 is equal in amplitude to the signal received by the buffer module 100; the gain feedback circuit 212 provides different sizes of gain because the resistance Rg is set and the resistance values are different.
[0036] When the required gain size is 1, the switches S1 and S2 are connected to the resistance Rf1 by controlling the external digital control signal, that is, Figure 2 the connection mode in , the switches S1 and S2 are connected to the resistance Rf2, and so on. By changing the resistance values of the resistances Rf2, Rf3, Rf4, Rg2, Rg3, and Rg4, the output gain size can be changed. By controlling the on port of the switchable switch 220, the output gain size of the programmable gain amplifier can be controlled to meet different test requirements. In order to enable the gain module 200 to have sufficient common-mode rejection ratio, the resistances Rf1, Rf2, Rf3, and Rf4 in the feedback circuit 210 are selected to be high-precision resistances, for example, the precision can be 0.01%. It can be understood that the number of the feedback circuit 210 can be set according to the gain range required by the user, and the resistance values can be selected according to the gain size.
[0037] In some embodiments of the present application, referring to Figure 1 and Figure 3 , the input signal is a single-ended signal, the buffer module 100 includes two operational amplifiers 110, the negative input end of the operational amplifier 110 is connected to one end of the gain module 200, and the output end is connected to the other end of the gain module 200 and the input end of the output amplification module 300, the positive input end of one of the operational amplifiers 110 is connected to the input signal, and the positive input end of the other operational amplifier 110 is grounded.
[0038] Specifically, the buffer module 100 includes two operational amplifiers 110, when the input signal is a single-ended signal, the positive input end of one of the operational amplifiers 110 is grounded, and the positive input end of the other operational amplifier 110 receives the input signal, the negative input ends of the two operational amplifiers 110 are respectively connected to the two switchable switches 220 of the buffer module 100, and the output ends are connected to the input ends of the feedback circuit 210 and the output amplification module 300.
[0039] In some embodiments of the present application, referring to Figure 1 and Figure 2, the input signal is a differential signal, including a first differential signal and a second differential signal, the buffer module 100 includes two operational amplifiers 110, the negative input end of the operational amplifier 110 is connected with one end of the gain module 200, and the output end is connected with the other end of the gain module 200 and the input end of the output amplification module 300, wherein the positive input end of one of the operational amplifiers 110 is connected with the first differential signal, and the positive input end of the other operational amplifier 110 is connected with the second differential signal.
[0040] Specifically, the buffer module 100 includes two operational amplifiers 110, when the input signal is a differential signal, the positive input end of one of the operational amplifiers 110 is used for receiving the first differential signal Signal_P INPUT, and the positive input end of the other operational amplifier 110 is used for receiving the second differential signal Signal_N INPUT, the negative input end of the two operational amplifiers 110 is connected with two switchable switches 220 of the buffer module 100 respectively, and the output end is connected with the feedback circuit 210 and the input end of the output amplification module 300.
[0041] In some embodiments of the utility model, refer to Figure 3 And Figure 4 The buffer module 100 further includes two compensation circuits 120, one end of the two compensation circuits 120 is connected with the negative input end of the two operational amplifiers 110 respectively, and the other end is connected with the output end of the two operational amplifiers 110 respectively.
[0042] Specifically, the buffer module 100 further includes two compensation circuits 120, one of the operational amplifiers 110 is provided with one compensation circuit 120, one end of the compensation circuit 120 is connected with the negative input end of the operational amplifier 110, and the other end is connected with the output end of the operational amplifier 110. Because the operational amplifier 110 exists input parasitic capacitance, therefore resistance Rf1 or Rf2 or Rf3 or Rf4 and parasitic capacitance in gain module 200 can form a second pole on loop gain curve, thereby causing programmable gain amplifier to be in underdamped state, and further causing output unstable. In order to solve this problem, the compensation circuit 120 is arranged on the feedback path of the operational amplifier 110, so as to compensate the output of the programmable gain amplifier, thereby solving the problem that the output of the operational amplifier 110 is unstable, and further improving the performance of the programmable gain amplifier.
[0043] In some embodiments of the utility model, refer to Figure 3 And Figure 4The compensation circuit 120 comprises a first switch S3 and a first capacitor C1, one end of the first switch S3 is connected with the output end of the operational amplifier 110, the positive pole of the first capacitor C1 is connected with the other end of the first switch S3, and the negative pole of the first capacitor C1 is connected with the negative input end of the operational amplifier 110; wherein the first switch S3 is used for being opened or closed according to the gain size.
[0044] Specifically, the compensation circuit 120 is composed of the first switch S3 and the first capacitor C1, the first switch S3 and the first capacitor C1 are connected in series, and then are connected in parallel with the operational amplifier 110, and the negative pole of the first capacitor C1 is connected with the negative input end of the operational amplifier 110, wherein the first switch S3 is used for being opened or closed according to the gain size, so as to control whether the compensation circuit 120 needs to be connected to the whole circuit system.
[0045] When the gain is small, such as 1, due to the existence of the input parasitic capacitor of the operational amplifier 110, the resistance Rf1 or Rf2 or Rf3 or Rf4 in the gain module 200 and the parasitic capacitor will form a second pole on the loop gain curve, which will cause the system to be in an underdamped state, therefore, the first switch S3 is controlled to be closed, so that the first capacitor C1 is connected to the feedback path of the operational amplifier 110, thereby forming a zero point compensation, so as to solve the problem of unstable output of the operational amplifier 110.
[0046] When the gain is large, such as 8, due to the increase of the gain of the operational amplifier 110 and the decrease of the bandwidth, the second pole can appear after the cross-over frequency, at this time, the output of the whole operational amplifier 110 has been stabilized, and the compensation effect of the first capacitor C1 is not needed, therefore, the first switch S3 is controlled to be opened.
[0047] In some embodiments of the present application, Figure 3 and Figure 4 The output amplification module 300 comprises two gain resistors R1, a differential amplifier 310 and two feedback resistors R2, the positive and negative input ends of the differential amplifier 310 are connected with the other end of the gain module 200 and the output end of the buffer module 100 through the gain resistors R1 respectively, and the two ends of the feedback resistors R2 are connected with the input end and the output end of the differential amplifier 310 respectively.
[0048] Specifically, as Figure 3 and Figure 4As shown, the input amplification module includes two gain resistors R1, a differential amplifier 310 and two feedback resistors R2. The signal amplified by the gain module 200 and buffered by the operational amplifier 110 is transmitted to the positive and negative input terminals of the differential amplifier 310 through the gain resistors R1, and one end of one of the feedback resistors R2 is connected to the positive input terminal of the differential amplifier 310, and the other end is connected to the negative output terminal of the differential amplifier 310, and one end of the other feedback resistor R2 is connected to the negative input terminal of the differential amplifier 310, and the other end is connected to the positive output terminal of the differential amplifier 310. By selecting a differential amplifier 310 of a suitable model specification, the output accuracy of the programmable gain amplifier can be improved.
[0049] In some embodiments of the utility model, as shown in Figure 3 and Figure 4 As shown, the output amplification module 300 further includes a bandwidth adjustment circuit 340, and two ends of the bandwidth adjustment circuit 340 are respectively connected to the input terminal and the output terminal of the differential amplifier 310. In order to meet the needs of different output bandwidths, the programmable gain amplifier provided by the utility model is provided with two bandwidth adjustment circuits 340 for adjusting the bandwidth of the output signal, one of which is connected to the positive input terminal and the negative output terminal of the differential amplifier 310, and the other is connected to the negative input terminal and the positive output terminal of the differential amplifier 310.
[0050] In some embodiments of the utility model, as shown in Figure 3 and Figure 4 The bandwidth adjustment circuit 340 includes a second switch S4 and a second capacitor C2, one end of the second switch S4 is connected to the output terminal of the differential amplifier 310, and one end of the second capacitor C2 is connected to the input terminal of the differential amplifier 310, and the other end is connected to the other end of the second switch S4.
[0051] Specifically, each bandwidth adjustment circuit 340 includes a second switch S4 and a second capacitor C2, the second switch S4 is connected in series with the second capacitor C2, and the series connection is connected to the input terminal and the output terminal of the differential amplifier 310, wherein the second switch S4 is used to disconnect or connect according to the needs of the tester for the bandwidth, so as to control whether the second capacitor C2 is connected to the circuit.
[0052] When the test needs a small-bandwidth output signal, the second switch S4 is controlled to be closed, so that the second capacitor C2 is connected to the circuit, thereby forming a first-order active low-pass filter, so that the signal can be output without loss. When the test needs a large-bandwidth signal, the second switch S4 is controlled to be disconnected, so that the second capacitor C2 will not be connected to the circuit, and at this time the output bandwidth of the differential amplifier 310 depends on the gain of the gain module 200, so as to meet the needs of the large-bandwidth signal. Wherein the second switch S4 can be an optical coupling switch or a relay switch or other switches with control function, which can be selected according to the actual use needs.
[0053] The utility model still provides a kind of signal measurement system, and the signal measurement system includes the programmable gain amplifier of the above utility model.
[0054] According to the signal measurement system of the utility model embodiment, at least has following technical effect: by setting the programmable gain amplifier of the utility model, the gain demand of different input signals can be satisfied, and signal can be amplified to close to full scale of analog-digital converter, so that the best test precision and test performance can be achieved.
[0055] The above embodiments of the utility model are described in detail in combination with the drawings, but the utility model is not limited to the above embodiments, and various changes can be made within the knowledge range possessed by ordinary skilled persons in the art without departing from the purpose of the utility model.In addition, the embodiments and features in the embodiments of the utility model can be combined with each other without conflict.
Claims
1. A programmable gain amplifier, characterized by, The application relates to a signal processing circuit. The signal processing circuit comprises: a buffer module for receiving an input signal; a gain module, one end of which is connected with the input end of the buffer module, and the other end of which is connected with the output end of the buffer module; an output amplification module, the input end of which is connected with the other end of the gain module and the output end of the buffer module, and the output end of which is used for outputting a corresponding output signal; wherein the gain module comprises: at least two feedback circuits, one end of which is connected with the output end of the buffer module; 2. The programmable gain amplifier of claim 1, wherein, at least one switchable switch, one end of which is connected with the input end of the buffer module, and the other end of which is connected with the other end of the feedback circuit, and the switchable switch is used for communicating with one of the feedback circuits.
3. The programmable gain amplifier of claim 1, wherein, The feedback circuit is used for providing different sizes of gain, and the at least two feedback circuits are one sampling feedback circuit and multiple gain feedback circuits. The input signal is a single-ended signal, and the buffer module comprises:
4. The programmable gain amplifier of claim 1, wherein, two operational amplifiers, the negative input end of which is connected with one end of the gain module, and the output end of which is connected with the other end of the gain module and the input end of the output amplification module, wherein the positive input end of one of the operational amplifiers is connected with the input signal, and the positive input end of the other operational amplifier is grounded. The input signal is a differential signal, comprising a first differential signal and a second differential signal, and the buffer module comprises:
5. Programmable gain amplifier according to claim 3 or 4, characterized in that, two operational amplifiers, the negative input end of which is connected with one end of the gain module, and the output end of which is connected with the other end of the gain module and the input end of the output amplification module, wherein the positive input end of one of the operational amplifiers is connected with the first differential signal, and the positive input end of the other operational amplifier is connected with the second differential signal. The buffer module further comprises:
6. The programmable gain amplifier of claim 5, wherein, two compensation circuits, one end of each of the two compensation circuits being connected with the negative input end of each of the two operational amplifiers, and the other end of each of the two compensation circuits being connected with the output end of each of the two operational amplifiers. The compensation circuit comprises: a first switch, one end of which is connected with the output end of the operational amplifier; a first capacitor, the positive pole of which is connected with the other end of the first switch, and the negative pole of which is connected with the negative input end of the operational amplifier; 7. The programmable gain amplifier of claim 1, wherein, wherein the first switch is used for being turned on or turned off according to the gain size. The output amplification module comprises: two gain resistors; a differential amplifier, the positive and negative input ends of which are connected with the other end of the gain module and the output end of the buffer module through the gain resistors; 8. The programmable gain amplifier of claim 7, wherein, two feedback resistors, the two ends of which are connected with the input end and the output end of the differential amplifier. The output amplification module further comprises:
9. The programmable gain amplifier of claim 8, wherein, a bandwidth adjustment circuit, the two ends of which are connected with the input end and the output end of the differential amplifier. The bandwidth adjustment circuit comprises: a second switch, one end of which is connected with the output end of the differential amplifier; A second capacitor, one end of which is connected to the input end of the differential amplifier, and the other end of which is connected to the other end of the second switch.
10. A signal measurement system, characterized by, Comprising: The programmable gain amplifier of any one of claims 1 to 9.