Differential gain adjustable amplifier with constant closed loop bandwidth, gain adjustment method

Abstract

The application provides a closed-loop bandwidth constant differential gain adjustable amplifier, comprising an amplification module, a first impedance unit and a second impedance unit; the amplification module is sequentially provided with a differential-mode transconductance unit, a differential-mode feedback circuit, a common-mode transconductance unit and an adjustable common-mode point extraction network from an input end to an output end; the differential-mode feedback circuit comprises an adjustable differential-mode capacitor unit; the adjustable common-mode point extraction network comprises a common-mode capacitor group, and the common-mode capacitor group comprises at least one adjustable capacitor. The differential gain adjustable amplifier of the application can keep the closed-loop system bandwidth constant in a large range of feedback coefficient changes under the premise that the power consumption is controllable and the process difficulty is not increased, thereby meeting the application requirements of 4D imaging millimeter radar. The gain adjustable method provided by the application also has corresponding advantages.

Description

Technical Field

[0001] This invention belongs to the field of millimeter-wave radar technology, and particularly relates to a differential gain adjustable amplifier with constant closed-loop bandwidth and a corresponding gain adjustment method. Background Technology

[0002] Differential gain adjustable amplifiers are an indispensable component in many systems, such as millimeter-wave radar receivers. Due to significant differences in signal strength across various scenarios, they can be used to achieve gain compensation for different situations, effectively reducing the dynamic range of subsequent circuits. Adjustable gain amplifiers have many performance parameters, and often improving one parameter will degrade another. Especially in high-bandwidth applications, balancing bandwidth and power consumption is crucial.

[0003] Taking the practical application of 4D imaging radar technology as an example, 4D imaging radar technology enhances the object detection function of traditional millimeter-wave radar and can work well in various weather conditions. Generally, 4D imaging radar is based on ordinary millimeter-wave radar, adding the detection and analysis of target height data, thus enabling the perception of information in four dimensions: distance, azimuth, altitude, and speed. It is foreseeable that multi-sensor fusion autonomous driving solutions will remain the mainstream in the industry for the next few years, and 4D imaging radar, as a high-end millimeter-wave radar, will obviously occupy a place in this field.

[0004] If the bandwidth requirement of the entire gain amplifier is low, such as in mainstream low-resolution millimeter-wave radar where the system bandwidth W is around 10MHz, then the gain amplifier only needs to be designed with a bandwidth of 2.1GHz (210×10MHz) while ensuring stability of 700MHz (70×10MHz). However, in the design of 4D imaging millimeter-wave radar, due to the significantly increased system bandwidth, for example, a system bandwidth W=100MHz, the amplifier requires a bandwidth of 21GHz (210×100MHz) while ensuring stability of 7GHz. To achieve 7GHz stability, if the load capacitance is 10pF, the transconductance gm needs to reach 500ms. To generate such a transconductance gm, the current might need to reach 100mA, which is unacceptable in terms of power consumption. In this case, more difficult requirements are placed on power consumption and even the entire manufacturing process.

[0005] Therefore, in 4D imaging radar applications, variable gain amplifiers require both high bandwidth (>100MHz) and a wide adjustable gain range. Existing amplifier design methods struggle to meet these requirements while maintaining controllable power consumption, and also significantly increase the demands on manufacturing processes, hindering widespread production. Thus, existing differential gain adjustable amplifiers have shortcomings in 4D imaging millimeter-wave radar applications, limiting the development of 4D imaging millimeter-wave radar technology.

[0006] Therefore, it is necessary to study a differential gain adjustable amplifier with constant closed-loop bandwidth and a corresponding gain adjustment method for use in the receiver of 4D imaging millimeter-wave radar, so as to achieve gain adjustment under high bandwidth, thereby further promoting the in-depth development and widespread application of 4D imaging millimeter-wave radar technology. Summary of the Invention

[0007] This invention addresses all or part of the problems of the prior art. One aspect of this invention provides a differential gain adjustable amplifier with constant closed-loop bandwidth and a corresponding gain adjustment method, suitable for receivers of 4D imaging millimeter-wave radar. Another aspect of this invention provides a gain adjustment method based on the differential gain adjustable amplifier of this invention.

[0008] This invention provides a differential gain adjustable amplifier with constant closed-loop bandwidth, comprising an amplification module, a first impedance unit, and a second impedance unit. The amplification module is a dual-input, dual-output circuit, with its input terminal connected in series with the first impedance unit and its input and output terminals connected in parallel with the second impedance unit. From input to output, the amplification module sequentially includes a differential-mode transconductance unit, a differential-mode feedback circuit, a common-mode transconductance unit, and an adjustable common-mode point extraction network. The output terminal of the differential-mode transconductance unit is connected to the input terminal of the differential-mode feedback circuit. The output terminal of the common-mode transconductance unit is connected to the input terminal of the differential-mode feedback circuit. The input terminal of the common-mode transconductance unit is connected to the output terminal of the adjustable common-mode point extraction network, and the input terminal of the adjustable common-mode point extraction network is connected to the output terminal of the differential-mode feedback circuit. The differential-mode feedback circuit includes an adjustable differential-mode capacitor unit. The adjustable common-mode point extraction network includes a common-mode capacitor bank, which includes at least one adjustable capacitor. The method for adjusting the gain of the entire amplifier is to adjust the feedback coefficient. By setting an adjustable differential-mode capacitor unit in conjunction with the adjustable common-mode point extraction network, the differential-mode bandwidth can be adjusted by adjusting the adjustable differential-mode capacitor unit, thus offsetting the change in the feedback coefficient when adjusting the gain. At the same time, by changing the adjustable capacitor in the adjustable common-mode point extraction network, the influence of the capacitance value of the adjustable differential-mode capacitor unit on the common-mode bandwidth can be offset (because the common-mode bandwidth is not affected by the change in the feedback coefficient, so it does not need to change with the change in gain). Thus, it is possible to achieve increased system bandwidth, stable closed-loop bandwidth, controllable power consumption, and no increase in process difficulty, meeting the application requirements of 4D imaging millimeter-wave radar receivers.

[0009] The common-mode capacitor bank includes a first common-mode capacitor unit and a second common-mode capacitor unit; one end of the first common-mode capacitor unit is connected to the input terminal of the adjustable common-mode point extraction network, and the other end is connected to the output terminal of the adjustable common-mode point extraction network; the second common-mode capacitor unit includes several adjustable capacitors, one end of which is grounded, and the other end is connected to the output terminal of the adjustable common-mode point extraction network.

[0010] The adjustable common-mode point extraction network has two input terminals, which are respectively connected to the first common-mode capacitor unit; the first common-mode capacitor unit includes several adjustable capacitors and / or several fixed capacitors; the input terminals of the adjustable common-mode point extraction network are provided with several resistive elements.

[0011] The differential-mode transconductance unit includes several adjustable transconductance transistors. The transconductance of the differential-mode transconductance unit can be adjusted. Adjusting the transconductance of the differential-mode transconductance unit will not affect the common-mode bandwidth, and it can assist the adjustable differential-mode capacitor unit in coordinated adjustment, which can better offset the change in the feedback coefficient when adjusting the overall gain.

[0012] Another aspect of the present invention provides a gain adjustment method based on a differential gain adjustable amplifier with constant closed-loop bandwidth provided in one aspect of the present invention, comprising: obtaining the common-mode bandwidth of the amplification module and the closed-loop bandwidth designed for stability; setting the impedance ratio of the first impedance unit and the second impedance unit based on the target gain to be adjusted; obtaining the target feedback coefficient of the amplification module based on the impedance ratio; setting the target capacitance value of the adjustable differential-mode capacitor unit based on the target feedback coefficient to ensure that the closed-loop bandwidth remains constant; and setting the capacitance value of the adjustable common-mode point extraction network based on the target capacitance value to ensure that the common-mode bandwidth remains constant.

[0013] The method for setting the target capacitance value includes: the differential-mode transconductance unit includes a plurality of adjustable transconductance transistors; the adjustment range of the differential-mode transconductance unit is obtained; the transconductance setting value of the differential-mode transconductance unit is determined based on the adjustment range; and the target capacitance value is calculated based on the closed-loop bandwidth, the target feedback coefficient, and the transconductance setting value.

[0014] Let the impedance values ​​of the first impedance unit and the second impedance unit be Z1 and Z2 respectively, the feedback coefficient be β, and the gain coefficient of the amplification module be A, where A×β≥10; given the target gain to be achieved, use the formula... The impedance ratio is determined. A×β is the closed-loop gain, and its bandwidth is the closed-loop bandwidth. In order for the target gain to be determined by the ratio of Z2 and Z1, A×β, that is, the closed-loop gain, must be greater than 10.

[0015] Based on the impedance ratio, using the formula The target feedback coefficient is calculated.

[0016] Let the target capacitance value be denoted as C. m The transconductance setting value of the differential mode transconductance unit is denoted as g. dm The differential-mode bandwidth of the gain coefficient A is... The calculation of the target capacitance value includes: obtaining the value based on the closed-loop bandwidth. The fixed value is determined by the fixed value, the target feedback coefficient, and g. dm Determine C m .

[0017] The transconductance value of the common-mode transconductance unit is denoted as g. cm The capacitance value of the adjustable common-mode point extraction network is denoted as C. n The method for setting the capacitance value of the adjustable common-mode point extraction network includes: the common-mode bandwidth is... , is a fixed value, determined by C m Determine C n .

[0018] Let the capacitance value of the first common-mode capacitor unit be denoted as C. cm1 The capacitance value of the second common-mode capacitor unit is denoted as C. cm2 ; , by C n Determine C cm1 and / or C cm2 .

[0019] Compared with the prior art, the main beneficial effects of the present invention are: 1. The differential gain adjustable amplifier with constant closed-loop bandwidth of the present invention has a simple structure. By setting an adjustable differential mode capacitor unit in conjunction with the adjustable common mode extraction network, it can maintain a constant closed-loop system bandwidth over a wide range of feedback coefficient changes while keeping power consumption controllable and compatible with current process technology. This provides a differential gain adjustable amplifier with a large bandwidth and a wide adjustable gain range suitable for 4D imaging millimeter-wave radar receivers, which better meets the application requirements of 4D imaging millimeter-wave radar without increasing the difficulty of chip manufacturing process while keeping power consumption controllable.

[0020] 2. The gain adjustment method of this invention can achieve a wider range of gain adjustment compared to existing differential gain-adjustable amplifiers without increasing the complexity of the manufacturing process. Within a defined bandwidth, a larger gain adjustment range can be achieved; and even with a defined desired gain adjustment range, a larger bandwidth can be achieved. It can effectively maintain power consumption at a low level during a wide range of gain adjustment. Attached Figure Description

[0021] Figure 1This is a schematic diagram of a differential gain adjustable amplifier according to Embodiment 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of the magnification module according to Embodiment 1 of the present invention.

[0023] Figure 3 This is a schematic diagram of the adjustable common-mode point extraction network in Embodiment 1 of the present invention.

[0024] Figure 4 This is a schematic diagram of the gain adjustment method according to Embodiment 1 of the present invention.

[0025] Figure 5 This is a schematic diagram of the enlarged module according to Embodiment 2 of the present invention. Detailed Implementation

[0026] The technical solutions in specific embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The operation of the embodiments is described in a specific order in the following embodiments. This order is provided to better understand the details of the embodiments and to fully understand the invention, but this order does not limit the scope of the invention.

[0028] Example 1 In Embodiment 1 of the present invention, as Figure 1 As shown, a differential gain adjustable amplifier with constant closed-loop bandwidth includes an amplification module 1, a first impedance unit 2, and a second impedance unit 3. The example shows two first impedance units 2 and two second impedance units 3. For simplicity, one impedance unit is shown as one impedance element; in practical applications, impedance units can be composed of various impedance elements (such as inductors, resistors, etc.) or multiple impedance elements, and are not limited to any one type. The impedance value of the first impedance unit 2 is denoted as Z1, and the impedance value of the second impedance unit is denoted as Z2. Figure 1 As shown, amplifier module 1 is a dual-input, dual-output circuit, with the input being V. in The output is V out .like Figure 2 As shown, the amplifier module 1 is provided with a differential mode transconductance unit 10, a differential mode feedback circuit 11, a common mode transconductance unit 12, and an adjustable common mode point extraction network (TVSN) sequentially from the input to the output. cm(Sensing Network). The output of the differential-mode transconductance unit 10 is connected to the input of the differential-mode feedback circuit 11. The output of the common-mode transconductance unit 12 is also connected to the input of the differential-mode feedback circuit 11. The input of the common-mode transconductance unit 12 is connected to the output of the adjustable common-mode point extraction network (TVSN), and the input of the TVSN is connected to the output of the differential-mode feedback circuit 11. The example differential-mode feedback circuit 11 has two symmetrically arranged sets, each including an adjustable differential-mode capacitor unit 110 and a transconductance transistor 111. Figure 2 The example adjustable differential-mode capacitor unit 110 is implemented using a single adjustable capacitor. In practical applications, an adjustable differential-mode capacitor unit 110 can also be implemented using multiple adjustable capacitors, and the number of transconductance transistors 111 can also be greater, without limitation.

[0029] The example adjustable common-mode point extraction network TVSN includes a common-mode capacitor bank, such as... Figure 3 As shown, the example includes two first common-mode capacitor units T1 and one second common-mode capacitor unit T2. The two first common-mode capacitor units T1 in this example are two fixed capacitors, one end of which is connected to the input terminal in of the adjustable common-mode point extraction network, and the other end is connected to the output terminal out of the adjustable common-mode point extraction network. The second common-mode capacitor unit T2 in this example is an adjustable capacitor, one end of which is grounded, and the other end is connected to the output terminal out of the adjustable common-mode point extraction network. In practical applications, the second common-mode capacitor unit T2 can have more adjustable capacitors; this is not limited. The first common-mode capacitor unit T1 in this example is a fixed capacitor. In some implementations, the first common-mode capacitor unit T1 can be partially or entirely made up of adjustable capacitors; this is not limited. In this embodiment, the adjustable common-mode point extraction network has two input terminals in, each with a resistor element T3. Each input terminal in is connected to one first common-mode capacitor unit T1.

[0030] In this embodiment, reference Figure 1 Let the impedance values ​​of the first and second impedance units be Z1 and Z2 respectively, the feedback coefficient be denoted as β, and the gain coefficient of the amplification module be denoted as A. A × β is the closed-loop gain. Bandwidth refers to the frequency range within which the required gain can be achieved; the bandwidth corresponding to the closed-loop gain is the closed-loop bandwidth. Generally, the formula for calculating gain is... In this embodiment, A×β is much greater than 1, and the gain can be completely determined by Z1 and Z2. Therefore, the target gain can be achieved by adjusting the ratio of Z1 and Z2.

[0031] In the example scenario, the overall gain adjustment range required by the differential gain adjustable amplifier is 2 to 20. The unit bandwidth from input to output of the entire amplification module 1 is denoted as W. In this embodiment, the differential-mode bandwidth of the gain coefficient A is characterized by n unit bandwidths W. In the example scenario, A×β is at least 10, which is sufficient to achieve a gain much greater than 1. The target gain, target feedback coefficient, and corresponding parameters are shown in Table 1 below.

[0032] Table 1. Example values ​​for target gain, target feedback coefficient, and differential bandwidth. Gain 2 20 β 1 / 3 1 / 21 Differential bandwidth 30W 210W As shown in the table above, following the traditional approach, if the differential-mode bandwidth of 210W cannot be changed, then to meet the high-gain requirement, amplifier module 1 needs to be designed with a bandwidth of 210W. Therefore, the closed-loop bandwidth at low gain, which is the bandwidth used for stability design (the phase margin at the gain frequency of module 1 on the system stability curve should not be less than 45 degrees), will be very large. See Table 2 below.

[0033] Table 2. Changes in closed-loop bandwidth due to gain adjustment Gain 2 20 β 1 / 3 1 / 21 Differential bandwidth 210W 210W Closed-loop bandwidth 70W 10W As shown in Tables 1 and 2, the differential-mode bandwidth of the gain coefficient A needs to be adjusted to maintain a constant closed-loop bandwidth. In the example case, this is achieved through dynamic adjustment of the differential-mode bandwidth, with the adjustment magnitude inversely proportional to β, as shown in Table 3 below.

[0034] Table 3. Dynamically Adjusting Differential Bandwidth to Maintain Constant Closed-Loop Bandwidth Gain 2 20 β 1 / 3 1 / 21 Differential bandwidth 30W 210W Closed-loop bandwidth 10W 10W In the traditional approach, since the differential-mode bandwidth of the gain coefficient A cannot be dynamically adjusted, if the required gain adjustment range is very small, such as 2 to 5, it may be possible to achieve this through subsequent process design. However, when a larger gain adjustment range needs to be met, the power consumption of the differential gain adjustable amplifier is very large, and the process difficulty is also greatly increased, making it difficult to be compatible with the current process technology.

[0035] The differential gain adjustable amplifier with constant closed-loop bandwidth in this embodiment can achieve a gain adjustment range of 2 to 20, but it is not limited to the actual situation. When the required gain adjustment range is 3 to 30 or other values, it can also be understood that the differential gain adjustable amplifier with constant closed-loop bandwidth of the present invention can also be implemented accordingly.

[0036] The common-mode bandwidth is not affected by changes in the feedback coefficient. In this embodiment, adjusting the differential-mode bandwidth of the gain coefficient A itself does not change the common-mode bandwidth. In this embodiment, this can be achieved by setting an adjustable differential-mode capacitor unit 110 and an adjustable common-mode point extraction network (TVSN) in the amplification module 1. Figure 4The example gain adjustment method includes: obtaining the common-mode bandwidth of the amplification module and the closed-loop bandwidth designed for stability; setting the impedance ratio of the first impedance unit and the second impedance unit based on the target gain to be adjusted; obtaining the target feedback coefficient of the amplification module based on the impedance ratio; setting the target capacitance value of the adjustable differential-mode capacitor unit based on the target feedback coefficient to ensure that the closed-loop bandwidth remains unchanged; and setting the capacitance value of the adjustable common-mode point extraction network based on the target capacitance value to ensure that the common-mode bandwidth remains unchanged.

[0037] In this embodiment, the method is achieved through formula The impedance ratio can be set according to the target gain to be achieved. This can be done using the formula... The target feedback coefficient can be calculated from the impedance ratio. Let the target capacitance value be denoted as C. m The transconductance setting value of the differential mode transconductance unit 10 is denoted as g. dm This setting value is adjusted according to the load being driven in the actual application, and is not limited to any specific application here. The differential-mode bandwidth of the gain coefficient A is calculated. The value can be determined. Based on the actual closed-loop bandwidth that needs to be maintained, obtain... The fixed value, along with the target feedback coefficient, allows us to calculate the value to be achieved by adjusting the differential mode bandwidth. In this embodiment, the transconductance setting value g of the differential mode transconductance unit 10 is... dm The capacitance value is a fixed preset value, which allows setting the capacitance value of the adjustable differential-mode capacitor unit 110 to satisfy gain adjustment and constant closed-loop bandwidth. For example, the capacitance value of the adjustable differential-mode capacitor unit 110 can be adjusted between 0.1 picofarads and 1 picofarad, and the corresponding capacitance value can be set within this adjustment range. Setting the capacitance value of the adjustable differential-mode capacitor unit 110 can be achieved using analog circuit adjustment or digital circuit adjustment, such as changing the voltage applied across the capacitor element or the number of capacitor elements connected in parallel, and is not limited to any particular method. The adjustment range of the capacitance value of the adjustable differential-mode capacitor unit 110 should match the range of change in the feedback coefficient, and this adjustment range can also be determined accordingly after determining the target gain β to be achieved.

[0038] In order to adjust the differential-mode bandwidth without changing the common-mode bandwidth, in this embodiment, the transconductance value of the common-mode transconductance unit 12 is denoted as g. cm The capacitance value of the adjustable common-mode point extraction network TVSN is denoted as C. n Methods for setting the capacitance value of the adjustable common-mode point extraction network TVSN include: common-mode bandwidth, i.e. , is a preset fixed value, determined by C m Determine C n In this embodiment, the capacitance value of the first common-mode capacitor unit is denoted as C. cm1 The capacitance value of the second common-mode capacitor unit is denoted as C. cm2 ; , by C n Determine C cm2 .like Figure 3 The capacitance values ​​of the two first common-mode capacitor units T1 in the example are both C. cm1 The capacitance value of the second common-mode capacitor unit T2 is C. cm2 The second common-mode capacitor unit T2 is an adjustable capacitor, which can be controlled by C. n Determine the capacitance value C to which the second common-mode capacitor unit T2 needs to be adjusted. cm2 In some implementations, the first common-mode capacitor unit T1 is also composed of several adjustable capacitors, which can be determined by C. n More flexible C settings cm1 and / or C cm2 This is not limited to this. By setting an adjustable common-mode point extraction network (TVSN), the common-mode voltage can be extracted, and a variable can be added to adjust the common-mode bandwidth so that it remains constant without affecting the differential-mode bandwidth.

[0039] Example 2 like Figure 5 As shown, the main difference between this embodiment and Embodiment 1 is that the differential-mode transconductance unit 10 is implemented using an adjustable transconductance transistor. The transconductance value of the differential-mode transconductance unit 10 can be adjusted. In this embodiment, the target capacitance value C is set in the gain adjustment method. m The method includes: obtaining the adjustment range of the differential-mode transconductance unit 10, and determining the transconductance setpoint g of the adjustable transconductance transistor based on the adjustment range. dm The target capacitance value is calculated based on the closed-loop bandwidth, target feedback coefficient, and transconductance setpoint. Transconductance is implemented in the chip using transistors. If the transconductance is to be adjusted via current, a 100-fold change in current through the transistor is required to change its transconductance by a 10-fold; excessively large current changes will cause the transistor to operate in an incorrect state. Therefore, without affecting circuit matching and noise levels, the specific adjustment range of the transistor's size can be obtained based on the actual situation, and the transconductance setpoint g of the adjustable transconductance transistor can be determined according to this range. dm Although the adjustment range cannot be too large, it can be used as an auxiliary to work with the adjustable differential mode capacitor unit 110 to achieve a constant closed-loop bandwidth, further improving the flexibility of the overall design.

[0040] The common English terms or letters used in this invention for clarity of description are for illustrative purposes only and are not limiting interpretations or specific uses. They should not be used to limit the scope of protection of this invention based on their possible Chinese translations or specific letters.

[0041] It should also be noted that in this article, relational terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

Claims

1. A differential gain adjustable amplifier with constant closed-loop bandwidth, characterized in that: It includes an amplification module, a first impedance unit, and a second impedance unit; The amplification module is a dual-input dual-output circuit, with the input end connected in series with the first impedance unit, and the input end and the output end connected in parallel with the second impedance unit; the amplification module is provided with a differential mode transconductance unit, a differential mode feedback circuit, a common mode transconductance unit and an adjustable common mode point extraction network in sequence from the input end to the output end. The output terminal of the differential mode transconductance unit is connected to the input terminal of the differential mode feedback circuit; the output terminal of the common mode transconductance unit is connected to the input terminal of the differential mode feedback circuit; the input terminal of the common mode transconductance unit is connected to the output terminal of the adjustable common mode point extraction network, and the input terminal of the adjustable common mode point extraction network is connected to the output terminal of the differential mode feedback circuit. The differential mode feedback circuit includes an adjustable differential mode capacitor unit; The adjustable common-mode point extraction network includes a common-mode capacitor bank, and the common-mode capacitor bank includes at least one adjustable capacitor. The common-mode capacitor bank includes a first common-mode capacitor unit and a second common-mode capacitor unit; one end of the first common-mode capacitor unit is connected to the input terminal of the adjustable common-mode point extraction network, and the other end is connected to the output terminal of the adjustable common-mode point extraction network; the second common-mode capacitor unit includes several adjustable capacitors, one end of which is grounded, and the other end is connected to the output terminal of the adjustable common-mode point extraction network.

2. The differential gain adjustable amplifier with constant closed-loop bandwidth according to claim 1, characterized in that: The adjustable common-mode point extraction network has two input terminals, which are respectively connected to the first common-mode capacitor unit; the first common-mode capacitor unit includes several adjustable capacitors and / or several fixed capacitors; the input terminals of the adjustable common-mode point extraction network are provided with several resistive elements.

3. The differential gain adjustable amplifier with constant closed-loop bandwidth according to any one of claims 1-2, characterized in that: The differential-mode transconductance unit includes several adjustable transconductance transistors.

4. A gain adjustment method, characterized in that: The differential gain adjustable amplifier with constant closed-loop bandwidth according to any one of claims 1-3 includes: Obtain the common-mode bandwidth and closed-loop bandwidth of the amplification module as part of the stability design; The impedance ratio of the first impedance unit and the second impedance unit is set based on the target gain that needs to be adjusted to achieve. The target feedback coefficient of the amplification module is obtained based on the impedance ratio; The target capacitance value of the adjustable differential mode capacitor unit is set based on the target feedback coefficient to ensure that the closed-loop bandwidth remains unchanged. The capacitance value of the adjustable common-mode point extraction network is set based on the target capacitance value to ensure that the common-mode bandwidth remains constant.

5. The gain adjustment method according to claim 4, characterized in that: The method for setting the target capacitance value includes: The differential mode transconductance unit includes a plurality of adjustable transconductance transistors, the adjustment range of the differential mode transconductance unit is obtained, and the transconductance setting value of the differential mode transconductance unit is determined based on the adjustment range; The target capacitance value is calculated based on the closed-loop bandwidth, the target feedback coefficient, and the transconductance setpoint.

6. The gain adjustment method according to claim 4, characterized in that: Let the impedance values ​​of the first impedance unit and the second impedance unit be Z1 and Z2 respectively, the feedback coefficient be β, and the gain coefficient of the amplification module be A, where A×β≥10; given the target gain to be achieved, use the formula... Determine the impedance ratio.

7. The gain adjustment method according to claim 6, characterized in that: Based on the impedance ratio, using the formula The target feedback coefficient is calculated.

8. The gain adjustment method according to any one of claims 4-7, characterized in that: Let the target capacitance value be denoted as C. m The transconductance setting value of the differential mode transconductance unit is denoted as g. dm The differential-mode bandwidth of the gain coefficient A is... ; The calculation of the target capacitance value includes: obtaining the value based on the closed-loop bandwidth. The fixed value is determined by the fixed value, the target feedback coefficient, and g. dm Determine C m .

9. The gain adjustment method according to claim 8, characterized in that: The transconductance value of the common-mode transconductance unit is denoted as g. cm The capacitance value of the adjustable common-mode point extraction network is denoted as C. n ; The method for setting the capacitance value of the adjustable common-mode point extraction network includes: the common-mode bandwidth is... , is a fixed value, determined by C m Determine C n .

10. The gain adjustment method according to claim 9, characterized in that: Let the capacitance value of the first common-mode capacitor unit be denoted as C. cm1 The capacitance value of the second common-mode capacitor unit is denoted as C. cm2 ; , by C n Determine C cm1 and / or C cm2 .

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