Gain programmable analog front-end circuit with common-mode adjustment

Abstract

The invention provides a gain programmable analog front-end circuit with common-mode adjustment. The circuit comprises a programmable gain amplification module, an output buffer module and a common-mode feedback module, the output of the programmable gain amplification module is connected with the input of the output buffer module, and the programmable gain amplification module is used for adjusting the input voltage gain; the outputs of the two ends of the output buffer module are used for driving a post-stage load and are connected with the common-mode feedback module; and the common-mode feedback module is connected with the programmable gain amplification module and the output of the output buffer module and is used for adjusting the common-mode voltage output by the output buffer module in real time according to requirements and adjusting the common-mode voltage to a required range. According to the analog front-end circuit, gain adjustment can be realized, a post-stage load can be driven, the common-mode voltage can be adjusted in real time according to requirements, and the output common-mode voltage can be adjusted to a required low-voltage range under the conditions that extra power consumption is not increased and original VGA current and input common mode are not changed.

Description

Technical Field

[0001] The invention relates to the technical field of integrated circuits, and in particular to a gain programmable analog front-end circuit with common-mode adjustment. Background Art

[0002] In order to meet the growing demand for data capacity, rate and throughput in data centers, the performance requirements for analog integrated circuits such as high-speed I / O interfaces are becoming increasingly stringent. As an important part of signal transmission, the analog front-end circuit needs to provide different gains to adapt to different input signal amplitudes and provide appropriate driving capabilities to drive the subsequent loads. At the same time, in order to reduce power consumption, different power supply voltages are often used in different modules of the signal path. The existence of different power supply voltages requires the common mode voltage of the signal path to be close to the low-voltage part. Therefore, the analog front-end circuit must be compatible with the common mode of the input signal at the same time, and provide a suitable output common mode to meet the needs of the subsequent stage.

[0003] At present, the industry mainly uses variable gain amplifiers (VGAs) in conjunction with common-mode adjustment circuits to solve the above needs. The following methods are commonly used to solve the common-mode voltage problem: 1. Use AC coupling to add coupling capacitors at different common-mode interfaces to separate different common-mode voltages. This method has a large capacitor area and is not very practical today with increasing integration; 2. Use a specific common-mode feedback method to adjust the common-mode voltage to the required voltage, usually adjusting the current of the VGA to change the common-mode voltage. However, this method will change the working state of the VGA while changing the common mode, and the conventional VGA common mode is also difficult to adjust to a relatively low range. To adjust the output common-mode voltage, the current I or R must be adjusted. Changing the resistor will directly change the gain and bandwidth of the amplifier, which cannot be used in many application scenarios. Therefore, the common-mode voltage is generally adjusted by adjusting the current. However, changing the current will also change the working state of the amplifier, so the current adjustment range is also limited. At the same time, because the resistor is close to the power supply, it is difficult to achieve a low voltage value for the output common mode. Summary of the invention

[0004] The purpose of the present invention is to provide a gain programmable analog front-end circuit with common-mode adjustment. The analog front-end circuit proposed in the circuit includes VGA, Buffer, and CMFB modules. The three modules cooperate to achieve gain adjustment, drive the subsequent load, and adjust the common-mode voltage in real time according to demand. The output common-mode voltage is adjusted to the required low-voltage range without increasing additional power consumption and changing the original VGA current and input common mode.

[0005] A gain programmable analog front-end circuit with common mode adjustment includes: a programmable gain amplifier module, an output buffer module and a common mode feedback module; The output of the programmable gain amplifier module is connected to the input of the output buffer module to adjust the input voltage gain; Both end outputs of the output buffer module are connected to the common mode feedback module to enhance the driving capability of the output voltage; The common-mode feedback module is connected to the output of the programmable gain amplifier module and the output buffer module, and is used to adjust the common-mode voltage output by the output buffer module in real time according to demand, and adjust the common-mode voltage to a required range.

[0006] Preferably, the programmable gain amplifier module includes: a first PMOS tube, a second PMOS tube, a third PMOS tube, a fourth PMOS tube, a first NMOS tube, a second NMOS tube, a third NMOS tube, a fourth NMOS tube, a fifth NMOS tube, a first resistor, a second resistor and a third resistor; The source of the first PMOS tube is connected to the power supply voltage, the gate is connected to the gate of the second PMOS tube, and the drain is connected to the drain of the first NMOS tube; The source of the second PMOS tube is connected to the power supply voltage, the gate is connected to the gate of the first PMOS tube, and the drain is connected to the drain of the second NMOS tube; The source of the first NMOS tube is connected to the drain of the fourth NMOS tube, and the gate is connected to INP; The source of the second NMOS tube is connected to the drain of the fifth NMOS tube, and the gate is connected to INM; The third resistor is connected to the source of the second NMOS transistor and the source of the first NMOS transistor; The source of the fourth NMOS tube is grounded; The source of the fifth NMOS tube is grounded; The source of the third PMOS tube is connected to the drain of the first NMOS tube, the gate is connected to the gate of the fourth PMOS tube, and the drain is connected to the first resistor; The source of the fourth PMOS tube is connected to the drain of the second NMOS tube, the gate is connected to the gate of the third PMOS tube, and the drain is connected to the second resistor; The drain of the third NMOS tube is connected to the first resistor and the second resistor, the source is grounded, and the gate is connected to Vcmc.

[0007] Preferably, the output buffer module comprises: a sixth NMOS tube, a seventh NMOS tube, an eighth NMOS tube and a ninth NMOS tube; The drain of the sixth NMOS tube is connected to the power supply voltage, the gate is connected to VOUTP1, and the source is connected to the drain of the eighth NMOS tube; The drain of the seventh NMOS tube is connected to the power supply voltage, the gate is connected to VOUTP1, and the source is connected to the drain of the eighth NMOS tube; The source of the eighth NMOS tube is grounded; The source of the ninth NMOS tube is grounded.

[0008] Preferably, the common mode feedback module comprises: a fourth resistor, a fifth resistor and an amplifier A first end of the fourth resistor is connected to VOUTP2, and a second end is connected to the fifth resistor and the input end of the amplifier; The second end of the fifth resistor is connected to VOUTM2, and the first end is connected to the fourth resistor and the input end of the amplifier; The input terminal of the amplifier is connected to Vref, and outputs Vcmc.

[0009] A gain programmable analog front-end circuit control method with common mode adjustment is applied to a gain programmable analog front-end circuit with common mode adjustment, comprising: Inputting the current Inp and the current Inm into a programmable gain amplifier module; The programmable gain amplifier module outputs a voltage VOUTP1 and a voltage VOUTMVOUTM1 to an output buffer module; The output buffer module outputs a voltage VOUTP2 and a voltage VOUTM2; The common-mode feedback module outputs a voltage Vcmc to the programmable gain amplifier module according to the voltage VOUTP2 and the voltage VOUTMVOUTM2.

[0010] Preferably, the programmable gain amplifier module outputs the voltage VOUTP1 and the voltage VOUTMVOUTM1 to the output buffer module, including: The programmable gain amplifier module changes the output load resistance to be close to the ground without changing the input part, and adds a third NMOS tube for the common mode adjustment tube; The output common mode changes from VDD-I*R to: Vcmo1=(Voutp1+Voutm1) / 2=I*(R+RN3), the common mode is transferred from the side close to the power supply to the side close to the ground, thereby reducing the common mode range.

[0011] Preferably, the output buffer module outputs the voltage VOUTP2 and the voltage VOUTM2 including: The output buffer module provides driving capability to drive the subsequent load: Vcmo1=(Voutp1+Voutm1) / 2, Vcmo2=(Voutp2+Voutm2) / 2, Vcmo2=Vcmo1-Vgs, Vgs is the gate and source voltage difference of the buffer input tube; Since there is a natural voltage difference Vgs between the input and output of the output buffer module, the common-mode voltage of the output is reduced, making the power supply voltage used in the subsequent stage lower.

[0012] Preferably, the common-mode feedback module outputs a voltage Vcmc to the programmable gain amplifier module according to the voltage VOUTP2 and the voltage VOUTM2, comprising: The common mode feedback module detects the output common mode voltage and compares it with the reference value Vref; The common-mode voltage signal Vcmc of the output control programmable gain amplifier module is used to adjust RN3 so that the common-mode voltage is stabilized near the reference value.

[0013] An electronic device comprises: a chip, a processor and a memory, wherein the memory is used to store computer program codes, and the computer program codes include computer instructions. When the chip executes the computer instructions, the electronic device executes a gain programmable analog front-end circuit control method with common-mode adjustment.

[0014] A computer-readable storage medium stores a computer program, wherein the computer program includes program instructions. When the program instructions are executed by a processor of an electronic device, the processor executes a gain programmable analog front-end circuit control method with common-mode adjustment.

[0015] The beneficial effects of the present invention are as follows: 1. The input part of the programmable gain amplifier module of the present invention is unchanged, so it is compatible with the input environment of the existing design. 2. The load resistance of the programmable gain amplifier module of the present invention is transferred to the ground end, which can achieve a lower output common-mode voltage adjustment range. 3. The output buffer module of the present invention reduces the output signal of the VGA by one Vgs, further reducing the common-mode voltage, and at the same time provides a strong driving capability to drive the subsequent load. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0018] Figure 1 A schematic diagram of the structure of a gain programmable analog front-end circuit with common mode adjustment according to the present invention; Figure 2 It is a schematic diagram of the structure of a programmable gain amplifier module of the present invention; Figure 3 It is a schematic diagram of the structure of the output buffer module of the present invention; Figure 4 It is a structural schematic diagram of the common mode feedback module of the present invention; Figure 5 The figure is a schematic diagram of the hardware structure of an electronic device of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0021] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0022] At present, the industry mainly uses variable gain amplifiers (VGAs) in conjunction with common-mode adjustment circuits to solve the above needs. The following methods are commonly used to solve the common-mode voltage problem: 1. Use AC coupling to add coupling capacitors at different common-mode interfaces to separate different common-mode voltages. This method has a large capacitor area and is not very practical today with increasing integration; 2. Use a specific common-mode feedback method to adjust the common-mode voltage to the required voltage, usually adjusting the current of the VGA to change the common-mode voltage. However, this method will change the working state of the VGA while changing the common mode, and the conventional VGA common mode is also difficult to adjust to a relatively low range. To adjust the output common-mode voltage, the current I or R must be adjusted. Changing the resistor will directly change the gain and bandwidth of the amplifier, which cannot be used in many application scenarios. Therefore, the common-mode voltage is generally adjusted by adjusting the current. However, changing the current will also change the working state of the amplifier, so the current adjustment range is also limited. At the same time, because the resistor is close to the power supply, it is difficult to achieve a low voltage value for the output common mode.

[0023] The input part of the programmable gain amplifier module of the present invention is unchanged, so it is compatible with the input environment of the existing design. The load resistance of the programmable gain amplifier module of the present invention is transferred to the ground terminal, which can achieve a lower output common mode voltage adjustment range. The output buffer module of the present invention reduces the output signal of the VGA by one Vgs, further reduces the common mode voltage, and provides a strong driving capability to drive the subsequent load.

[0024] Example 1 A gain programmable analog front-end circuit with common-mode adjustment, reference Figure 1 , including: a programmable gain amplifier module, an output buffer module and a common mode feedback module; The output of the programmable gain amplifier module is connected to the input of the output buffer module to adjust the input voltage gain; Both end outputs of the output buffer module are connected to the common-mode feedback module to enhance the driving capability of the output voltage; The common-mode feedback module is connected to the output of the programmable gain amplifier module and the output buffer module, and is used to adjust the common-mode voltage output by the output buffer module in real time according to demand, and adjust the common-mode voltage to a required range.

[0025] The analog front-end circuit proposed in the present invention includes a programmable gain amplifier module VGA, an output buffer module Buffer, and a common-mode feedback module CMFB module. The three modules cooperate to achieve gain adjustment, drive the subsequent load, and adjust the output common-mode voltage in real time according to demand, and adjust the common-mode voltage to the required low-voltage range.

[0026] Preferably, reference Figure 2The programmable gain amplifier module includes: a first PMOS tube, a second PMOS tube, a third PMOS tube, a fourth PMOS tube, a first NMOS tube, a second NMOS tube, a third NMOS tube, a fourth NMOS tube, a fifth NMOS tube, a first resistor, a second resistor and a third resistor; The source of the first PMOS tube is connected to the power supply voltage, the gate is connected to the gate of the second PMOS tube, and the drain is connected to the drain of the first NMOS tube; The source of the second PMOS tube is connected to the power supply voltage, the gate is connected to the gate of the first PMOS tube, and the drain is connected to the drain of the second NMOS tube; The source of the first NMOS tube is connected to the drain of the fourth NMOS tube, and the gate is connected to INP; The source of the second NMOS tube is connected to the drain of the fifth NMOS tube, and the gate is connected to INM; The third resistor is connected to the source of the second NMOS tube and the source of the first NMOS tube; The source of the fourth NMOS tube is grounded; The source of the fifth NMOS tube is grounded; The source of the third PMOS tube is connected to the drain of the first NMOS tube, the gate is connected to the gate of the fourth PMOS tube, and the drain is connected to the first resistor; The source of the fourth PMOS tube is connected to the drain of the second NMOS tube, the gate is connected to the gate of the third PMOS tube, and the drain is connected to the second resistor; The drain of the third NMOS tube is connected to the first resistor and the second resistor, the source is grounded, and the gate is connected to Vcmc.

[0027] The programmable gain amplifier (VGA) is a general-purpose amplifier that can control the amplification factor through the system as needed. It is mainly composed of a fully balanced differential amplifier module, a decoder module, and a resistor switch array module. The resistance ratio of the negative feedback resistor divider in the fully balanced differential amplifier module determines the maximum gain of the PGA, and the decoding result of the decoder module controls the resistor switch array module to adjust the attenuation of the input signal, ultimately achieving programmability of the gain. The programmable gain amplifier (VGA) achieves programmability of gain through the collaborative work of the fully balanced differential amplifier module, the decoder module, and the resistor switch array module. Specifically, the resistance ratio of the negative feedback resistor divider determines the maximum gain value of the amplifier, and the decoding result of the decoder module controls the resistor switch array module to adjust the attenuation of the input signal, ultimately achieving programmability of the gain.

[0028] Preferably, reference Figure 3 , the output buffer module includes: a sixth NMOS tube, a seventh NMOS tube, an eighth NMOS tube and a ninth NMOS tube; The drain of the sixth NMOS tube is connected to the power supply voltage, the gate is connected to VOUTP1, and the source is connected to the drain of the eighth NMOS tube; The drain of the seventh NMOS tube is connected to the power supply voltage, the gate is connected to VOUTP1, and the source is connected to the drain of the eighth NMOS tube; The source of the eighth NMOS tube is grounded; The source of the ninth NMOS tube is grounded.

[0029] The output buffer module is a component used to cache output data, and it plays a vital role in the data transmission process. The main function of the output buffer module is to cache the data output by the computer, and then transmit this data to the recipient at an appropriate time, thereby improving the efficiency and stability of data transmission. When data needs to be output, the data will be temporarily stored in the output buffer module. These data are stored in the memory and wait for transmission. Through caching technology, the output buffer module can reduce the frequent transmission of data, thereby improving the efficiency of data transmission. When the data in the buffer module reaches a certain amount, the transmission operation will be triggered to transmit the cached data to the recipient at one time. The output buffer module can also avoid data loss and confusion, and ensure the integrity and stability of the data.

[0030] Preferably, reference Figure 4 The common-mode feedback module includes: a fourth resistor, a fifth resistor and an amplifier A first end of the fourth resistor is connected to VOUTP2, and a second end is connected to the fifth resistor and the input end of the amplifier; The second end of the fifth resistor is connected to VOUTM2, and the first end is connected to the fourth resistor and the input end of the amplifier; The input of the amplifier is connected to Vref and the output is Vcmc.

[0031] The main function of the common-mode feedback module is to stabilize the output common-mode level of the op amp, suppress common-mode noise, and not limit the output swing of the op amp. Common-mode feedback adjusts the tail current of the op amp by introducing a feedback signal related to the output common-mode level, thereby stabilizing the output common-mode level. When the common-mode output level of the op amp is greater than the reference voltage, the feedback signal increases, resulting in an increase in the tail current and a decrease in the output common-mode level; conversely, the feedback signal decreases, the tail current decreases, and the output common-mode level increases. The common-mode feedback module obtains the output common-mode signal of the circuit through a common-mode sampling circuit, and then compares this signal with a reference signal. The compared error signal is amplified and input to the main amplifier to adjust the output common-mode voltage. For the input differential signal, the common-mode feedback loop will not have an effect, which is equivalent to an open circuit for the AC signal; but for the input common-mode signal, the common-mode feedback loop determines the output common-mode level, thereby affecting the accuracy and stability of the output common-mode level of the circuit. The common-mode feedback module can effectively suppress common-mode noise and improve the purity of the signal. For example, in a switched capacitor circuit, common-mode feedback can stabilize the output common-mode level of the op amp without limiting the output swing of the op amp, making it easy to integrate with the main integrator circuit. Common-mode feedback is also widely used in fully differential operational amplifiers to improve the stability and accuracy of the circuit by adjusting the output common-mode level.

[0032] Example 2 A gain programmable analog front-end circuit control method with common mode adjustment is applied to a gain programmable analog front-end circuit with common mode adjustment, comprising: S100, inputting the current Inp and the current Inm into a programmable gain amplifier module; The main functions of the programmable gain amplifier module include signal amplification, gain adjustment, impedance matching and noise suppression. Through programming control, the programmable gain amplifier can dynamically adjust its gain to adapt to different signal strengths and processing requirements. The programmable gain amplifier module can control its gain through programming to amplify the amplitude of the input signal. During the signal transmission process, impedance mismatch between devices may cause signal loss and increased noise. The programmable gain amplifier module can reduce signal loss and noise by adjusting the impedance of the signal to match the impedance of the receiving device.

[0033] S200, the programmable gain amplifier module outputs the voltage VOUTP1 and the voltage VOUTMVOUTM1 to the output buffer module; S300, the output buffer module outputs the voltage VOUTP2 and the voltage VOUTM2; The main functions of the output buffer module include providing amplification, protection and drive of the output signal. Signal amplification: The output buffer module can convert low-level signals into high-level signals, thereby increasing the amplitude and stability of the signal and avoiding signal loss or attenuation. Signal protection: It can protect the output signal from damage to the signal due to abnormal conditions such as overcurrent or discharge. Signal drive: The output buffer module can provide high drive capability, so that the output signal can drive multiple load circuits to achieve signal distribution and expansion.

[0034] S400 , the common-mode feedback module outputs a voltage Vcmc to the programmable gain amplifier module according to the voltage VOUTP2 and the voltage VOUTMVOUTM2 .

[0035] The main function of the common-mode feedback module is to stabilize the output common-mode level of the op amp, suppress common-mode noise, and not limit the output swing of the op amp. Common-mode feedback adjusts the tail current of the op amp by introducing a feedback signal related to the output common-mode level, thereby stabilizing the output common-mode level. When the common-mode output level of the op amp is greater than the reference voltage, the feedback signal increases, resulting in an increase in the tail current and a decrease in the output common-mode level; conversely, the feedback signal decreases, the tail current decreases, and the output common-mode level increases. The common-mode feedback module obtains the output common-mode signal of the circuit through a common-mode sampling circuit, and then compares this signal with a reference signal. The compared error signal is amplified and input to the main amplifier to adjust the output common-mode voltage. For the input differential signal, the common-mode feedback loop will not have an effect, which is equivalent to an open circuit for the AC signal; but for the input common-mode signal, the common-mode feedback loop determines the output common-mode level, thereby affecting the accuracy and stability of the output common-mode level of the circuit.

[0036] Preferably, the programmable gain amplifier module outputs the voltage VOUTP1 and the voltage VOUTMVOUTM1 to the output buffer module, including: The programmable gain amplifier module changes the output load resistance to be close to the ground without changing the input part, and adds a third NMOS tube for the common mode adjustment tube; The output common mode changes from VDD-I*R to: Vcmo1=(Voutp1+Voutm1) / 2=I*(R+RN3), the common mode is transferred from the side close to the power supply to the side close to the ground, thereby reducing the common mode range.

[0037] The VGA structure of the present invention adopts a folded structure. Without changing the input part, the output load resistance is changed to be close to the ground end, and the common mode adjustment tube N3 is added. The output common mode is changed from VDD-I*R to: Vcmo1=(Voutp1+Voutm1) / 2=I*(R+RN3); The common mode is transferred from the side close to the power supply to the side close to the ground, thereby reducing the common mode range. (RN3 is the equivalent resistance of the N3 tube).

[0038] Preferably, the output buffer module outputs the voltage VOUTP2 and the voltage VOUTM2 including: The output buffer module provides driving capability to drive the subsequent load: Vcmo1=(Voutp1+Voutm1) / 2, Vcmo2=(Voutp2+Voutm2) / 2, Vcmo2=Vcmo1-Vgs, Vgs is the gate and source voltage difference of the buffer input tube; Since there is a natural voltage difference Vgs between the input and output of the output buffer module, the common-mode voltage of the output is reduced, making the power supply voltage used in the subsequent stage lower.

[0039] Buffer, the output buffer provides driving capability to drive the subsequent load: Vcmo1=(Voutp1+Voutm1) / 2, Vcmo2=(Voutp2+Voutm2) / 2, Vcmo2=Vcmo1-Vgs, (Vgs is the gate and source voltage difference of the buffer input tube).

[0040] At the same time, since there is a natural voltage difference Vgs between the input and output of the buffer, the output common-mode voltage can be further reduced, making it possible for the subsequent stage to use a lower power supply voltage.

[0041] Preferably, the common mode feedback module outputs the voltage Vcmc to the programmable gain amplifier module according to the voltage VOUTP2 and the voltage VOUTM2, including: The common mode feedback module detects the output common mode voltage and compares it with the reference value Vref; The common-mode voltage signal Vcmc of the output control programmable gain amplifier module is used to adjust RN3 so that the common-mode voltage is stabilized near the reference value.

[0042] The CMFB common-mode feedback module detects the output common-mode voltage and compares it with the reference value Vref, and outputs a voltage signal Vcmc that controls the VGA common mode to adjust RN3 so that the common-mode voltage is stable near the reference value.

[0043] Example 3 An electronic device comprises: a chip, a processor and a memory, wherein the memory is used to store computer program codes, and the computer program codes include computer instructions. When the chip executes the computer instructions, the electronic device executes a gain programmable analog front-end circuit control method with common-mode adjustment.

[0044] refer to Figure 5 The electronic device 2 includes a processor 21, a memory 22, an input device 23, and an output device 24. The processor 21, the memory 22, the input device 23, and the output device 24 are coupled via a connector, and the connector includes various interfaces, transmission lines, or buses, etc., which are not limited in the embodiments of the present invention. It should be understood that in various embodiments of the present invention, coupling refers to mutual connection in a specific manner, including direct connection or indirect connection through other devices, for example, through various interfaces, transmission lines, buses, etc.

[0045] The processor 21 may be one or more graphics processing units (GPUs). When the processor 21 is a GPU, the GPU may be a single-core GPU or a multi-core GPU. Optionally, the processor 21 may be a processor group consisting of multiple GPUs, and the multiple processors are coupled to each other via one or more buses. Optionally, the processor may also be other types of processors, etc., which are not limited in the embodiments of the present invention.

[0046] The memory 22 can be used to store computer program instructions and various computer program codes including program codes for executing the scheme of the present invention. Optionally, the memory includes but is not limited to random access memory (RAM), read-only memory (ROM), erasable programmable read only memory (EPROM), or portable read only memory (CD-ROM), which is used for related instructions and data.

[0047] The input device 23 is used to input data and / or signals, and the output device 24 is used to output data and / or signals. The output device 24 and the input device 23 may be independent devices or an integrated device.

[0048] Example 4 A computer-readable storage medium stores a computer program, wherein the computer program includes program instructions. When the program instructions are executed by a processor of an electronic device, the processor executes a gain programmable analog front-end circuit control method with common-mode adjustment.

[0049] The input part of the programmable gain amplifier module of the present invention is unchanged, so it is compatible with the input environment of the existing design. The load resistance of the programmable gain amplifier module of the present invention is transferred to the ground terminal, which can achieve a lower output common mode voltage adjustment range. The output buffer module of the present invention reduces the output signal of the VGA by one Vgs, further reduces the common mode voltage, and provides a strong driving capability to drive the subsequent load.

[0050] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A gain programmable analog front-end circuit with common mode adjustment, characterized in that: include: Programmable gain amplifier module, output buffer module and common mode feedback module; The output of the programmable gain amplifier module is connected to the input of the output buffer module to adjust the input voltage gain; Both end outputs of the output buffer module are connected to the common mode feedback module to enhance the driving capability of the output voltage; The common-mode feedback module is connected to the output of the programmable gain amplifier module and the output buffer module, and is used to adjust the common-mode voltage output by the output buffer module in real time according to demand, and adjust the common-mode voltage to a required range; The programmable gain amplifier module includes: a first PMOS tube, a second PMOS tube, a third PMOS tube, a fourth PMOS tube, a first NMOS tube, a second NMOS tube, a third NMOS tube, a fourth NMOS tube, a fifth NMOS tube, a first resistor, a second resistor and a third resistor; The source of the first PMOS tube is connected to the power supply voltage, the gate is connected to the gate of the second PMOS tube, and the drain is connected to the drain of the first NMOS tube; The source of the second PMOS tube is connected to the power supply voltage, the gate is connected to the gate of the first PMOS tube, and the drain is connected to the drain of the second NMOS tube; The source of the first NMOS tube is connected to the drain of the fourth NMOS tube, and the gate is connected to INP; The source of the second NMOS tube is connected to the drain of the fifth NMOS tube, and the gate is connected to INM; The third resistor is connected to the source of the second NMOS transistor and the source of the first NMOS transistor; The source of the fourth NMOS tube is grounded; The source of the fifth NMOS tube is grounded; The source of the third PMOS tube is connected to the drain of the first NMOS tube, the gate is connected to the gate of the fourth PMOS tube, and the drain is connected to the first resistor; The source of the fourth PMOS tube is connected to the drain of the second NMOS tube, the gate is connected to the gate of the third PMOS tube, and the drain is connected to the second resistor; The drain of the third NMOS tube is connected to the first resistor and the second resistor, the source is grounded, and the gate is connected to Vcmc.

2. A gain programmable analog front-end circuit with common mode adjustment according to claim 1, characterized in that: The output buffer module includes: a sixth NMOS tube, a seventh NMOS tube, an eighth NMOS tube and a ninth NMOS tube; The drain of the sixth NMOS tube is connected to the power supply voltage, the gate is connected to VOUTP1, and the source is connected to the drain of the eighth NMOS tube; The drain of the seventh NMOS tube is connected to the power supply voltage, the gate is connected to VOUTP1, and the source is connected to the drain of the eighth NMOS tube; The source of the eighth NMOS tube is grounded; The source of the ninth NMOS tube is grounded.

3. A gain programmable analog front-end circuit with common mode adjustment according to claim 1, characterized in that: The common mode feedback module includes: a fourth resistor, a fifth resistor and an amplifier A first end of the fourth resistor is connected to VOUTP2, and a second end is connected to the fifth resistor and the input end of the amplifier; The second end of the fifth resistor is connected to VOUTM2, and the first end is connected to the fourth resistor and the input end of the amplifier; The input terminal of the amplifier is connected to Vref, and outputs Vcmc.

4. A method for controlling a gain programmable analog front-end circuit with common mode adjustment, applied to a gain programmable analog front-end circuit with common mode adjustment as claimed in any one of claims 1 to 3, characterized in that: include: Inputting the current Inp and the current Inm into a programmable gain amplifier module; The programmable gain amplifier module outputs a voltage VOUTP1 and a voltage VOUTMVOUTM1 to an output buffer module; The output buffer module outputs a voltage VOUTP2 and a voltage VOUTM2; The common-mode feedback module outputs a voltage Vcmc to the programmable gain amplifier module according to the voltage VOUTP2 and the voltage VOUTMVOUTM2.

5. A method for controlling a gain programmable analog front-end circuit with common mode adjustment according to claim 4, characterized in that The programmable gain amplifier module outputs the voltage VOUTP1 and the voltage VOUTMVOUTM1 to the output buffer module, including: The programmable gain amplifier module changes the output load resistance to be close to the ground without changing the input part, and adds a third NMOS tube for the common mode adjustment tube; The output common mode changes from VDD-I*R to: Vcmo1=(Voutp1+Voutm1) / 2=I*(R+RN3), the common mode is transferred from the side close to the power supply to the side close to the ground, thereby reducing the common mode range.

6. A method for controlling a gain programmable analog front-end circuit with common mode adjustment according to claim 5, characterized in that: The output buffer module output voltage VOUTP2 and voltage VOUTM2 include: The output buffer module provides driving capability to drive the subsequent load: Vcmo1=(Voutp1+Voutm1) / 2; Vcmo2=(Voutp2+Voutm2) / 2; Vcmo2=Vcmo1-Vgs, Vgs is the gate and source voltage difference of the buffer input tube; Since there is a natural voltage difference Vgs between the input and output of the output buffer module, the common-mode voltage of the output is reduced, making the power supply voltage used in the subsequent stage lower.

7. The method for controlling a gain programmable analog front-end circuit with common mode adjustment according to claim 5, characterized in that: The common mode feedback module outputs the voltage Vcmc to the programmable gain amplifier module according to the voltage VOUTP2 and the voltage VOUTM2, including: The common mode feedback module detects the output common mode voltage and compares it with the reference value Vref; The common-mode voltage signal Vcmc of the output control programmable gain amplifier module is used to adjust RN3 so that the common-mode voltage is stabilized near the reference value.

8. An electronic device, characterized in that: include: A chip, a processor and a memory, wherein the memory is used to store computer program codes, wherein the computer program codes include computer instructions. When the chip executes the computer instructions, the electronic device executes a gain programmable analog front-end circuit control method with common-mode adjustment as described in any one of claims 4 to 7.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which includes program instructions. When the program instructions are executed by a processor of an electronic device, the processor executes a gain programmable analog front-end circuit control method with common-mode adjustment as described in any one of claims 4 to 7.

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