Source series terminal driving circuit and source series terminal driving method

Abstract

The invention relates to the technical field of integrated circuits and provides a source series terminal driving circuit and a source series terminal driving method. According to the source series terminal driving circuit, a negative feedback mechanism based on a feedback control module is utilized, a current source of a pull-up branch and a current source of a pull-down branch are utilized, the amplitude of a reference voltage is taken as a reference, and the amplitude of an output differential voltage signal is equal to the amplitude of the reference voltage by adjusting the magnitude of a current flowing through a differential resistor; under the condition of low power supply voltage, extra current is introduced, and the amplitude of an output signal is improved to the amplitude of adjustable reference voltage based on a negative feedback mechanism; by keeping the common-mode voltage component of the output differential voltage signal unchanged, the requirement of alternating current coupling application can be met, the expenditure of extra circuits and other hardware for adjusting the power supply voltage is saved, the requirements of various interface protocols and high-speed digital integrated circuit interfaces can be flexibly adapted, and popularization and application are facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuits, and in particular to a source series terminal driving circuit and a source series terminal driving method. Background Art

[0002] In the relevant applications of high-speed digital integrated circuits, such as data centers, artificial intelligence, industrial control, smart cars, etc., higher and higher interface speeds are required to meet the requirements of high-performance data transmission. As the interface speed increases, power consumption has become an important consideration in integrated circuit design. In the prior art, the use of current mode logic (CML) drivers to build high-speed digital communication interfaces has the problem of high static power consumption and high termination voltage restrictions. The use of source-series-terminated (SST) drivers to build high-speed digital communication interfaces faces the problem that the amplitude of the output voltage of the SST driver is half of the power supply voltage. When the power supply voltage is low, the amplitude of the output voltage of the driver may not meet the electrical characteristics requirements of the interface protocol, which is not conducive to improving data transmission performance. The source-series terminal drivers, drive circuits, drive schemes, etc. in the prior art increase the amplitude of the output signal by increasing the power supply voltage, which leads to a significant increase in power consumption, especially with the increase in interface speed, which does not meet the requirements of reducing power consumption in applications such as data centers, artificial intelligence, industrial control, and smart cars.

[0003] To this end, the present application provides a source series terminal driving circuit and a source series terminal driving method, which can not only increase the amplitude of the output signal of the driver under low power supply voltage to meet the electrical characteristics requirements of the interface protocol, but also minimize power consumption while supporting higher interface speeds, which helps to meet the needs of high-performance data transmission and reduced power consumption in applications such as data centers, artificial intelligence, industrial control, and smart cars. Summary of the invention

[0004] In a first aspect, the present application provides a source series terminal driving circuit. The source series terminal driving circuit comprises: a pull-up branch and a pull-down branch, wherein when the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the magnitude of the current flowing through the differential resistor is determined based on the current source of the pull-up branch, and when the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the magnitude of the current flowing through the differential resistor is determined based on the current source of the pull-down branch, and the output voltage of the source series terminal driving circuit is the voltage on the differential resistor; a feedback control module, which is used to detect the amplitude of the output voltage, compare the amplitude of the output voltage with the amplitude of a reference voltage, and generate a current source control signal based on the difference between the amplitude of the output voltage and the amplitude of the reference voltage, wherein the current source control signal is used to control the current source of the pull-up branch when the driving voltage is high and the current source of the pull-down branch when the driving voltage is low, thereby adjusting the magnitude of the current flowing through the differential resistor so as to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage.

[0005] Through the first aspect of the present application, a negative feedback mechanism based on a feedback control module, using a current source of a pull-up branch and a current source of a pull-down branch, and taking the amplitude of a reference voltage as a reference, by adjusting the magnitude of the current flowing through the differential resistor, it helps to achieve an output differential voltage signal whose amplitude is equal to the amplitude of the reference voltage; in the case of low power supply voltage, additional current is introduced and the output signal amplitude is increased to an adjustable reference voltage amplitude based on a negative feedback mechanism; by keeping the common-mode voltage component of the output differential voltage signal unchanged, it helps to meet the needs of AC coupling applications, saves hardware overhead such as additional circuits for adjusting the power supply voltage, helps to flexibly adapt to the needs of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote application.

[0006] In a possible implementation of the first aspect of the present application, the feedback control module includes: an amplitude detection module, which is used to detect the amplitude of the output voltage, compare the amplitude of the output voltage with the amplitude of the reference voltage, and thus output the difference between the amplitude of the output voltage and the amplitude of the reference voltage; a digital-to-analog conversion circuit control logic, which is used to generate a control signal based on the difference between the amplitude of the output voltage and the amplitude of the reference voltage; and a digital-to-analog conversion circuit, which is used to generate the current source control signal based on the control signal.

[0007] In a possible implementation of the first aspect of the present application, when the amplitude of the output voltage is smaller than the amplitude of the reference voltage, the output voltage of the digital-to-analog conversion circuit increases based on the control signal, thereby increasing the current flowing through the differential resistor so as to increase the amplitude of the voltage on the differential resistor; when the amplitude of the output voltage is greater than the amplitude of the reference voltage, the output voltage of the digital-to-analog conversion circuit decreases based on the control signal, thereby reducing the current flowing through the differential resistor so as to reduce the amplitude of the voltage on the differential resistor.

[0008] In a possible implementation of the first aspect of the present application, the feedback control module is used to provide a negative feedback signal relative to the difference between the amplitude of the output voltage and the amplitude of the reference voltage, and the negative feedback signal is used to adjust the current flowing through the differential resistor so as to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage.

[0009] In a possible implementation of the first aspect of the present application, when the amplitude of the output voltage is smaller than the amplitude of the reference voltage, the negative feedback signal is used to increase the current flowing through the differential resistor so as to increase the amplitude of the voltage on the differential resistor; when the amplitude of the output voltage is greater than the amplitude of the reference voltage, the negative feedback signal is used to reduce the current flowing through the differential resistor so as to reduce the amplitude of the voltage on the differential resistor.

[0010] In a possible implementation manner of the first aspect of the present application, the driving voltage is an input differential voltage signal, and the output voltage is an output differential voltage signal.

[0011] In a possible implementation of the first aspect of the present application, the pull-up branch includes a PMOS tube pair, the PMOS tube pair is turned on when the pull-up branch is turned on, and the PMOS tube pair is turned off when the pull-up branch is turned off, the PMOS tube pair includes a first PMOS tube and a second PMOS tube, the first PMOS tube is connected to the first end of the differential resistor through a first series resistor, and the second PMOS tube is connected to the second end of the differential resistor through a second series resistor.

[0012] In a possible implementation of the first aspect of the present application, the pull-down branch includes an NMOS tube pair, the NMOS tube pair is turned on when the pull-down branch is turned on, and the NMOS tube pair is turned off when the pull-down branch is turned off, the NMOS tube pair includes a first NMOS tube and a second NMOS tube, the first NMOS tube is connected to the first end of the differential resistor through a third series resistor, and the second NMOS tube is connected to the second end of the differential resistor through a fourth series resistor.

[0013] In a possible implementation manner of the first aspect of the present application, the first series resistor and the second series resistor are used for impedance matching of the pull-up branch, and the third series resistor and the fourth series resistor are used for impedance matching of the pull-down branch.

[0014] In a possible implementation manner of the first aspect of the present application, the amplitude of the reference voltage is determined based on electrical characteristic provisions of an interface protocol associated with the source series terminal drive circuit.

[0015] In a possible implementation of the first aspect of the present application, the source series terminal drive circuit utilizes the feedback control module so that the amplitude of the output voltage is equal to the amplitude of the reference voltage, wherein the amplitude of the power supply voltage of the source series terminal drive circuit is smaller than the amplitude of the reference voltage.

[0016] In a possible implementation manner of the first aspect of the present application, the current source of the pull-up branch and the current source of the pull-down branch are used together to keep the common-mode voltage component of the output voltage equal to the reference voltage.

[0017] In a possible implementation of the first aspect of the present application, when the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the current flowing through the differential resistor is a pull-up current; when the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the current flowing through the differential resistor is a pull-down current, and the differential-mode voltage component of the output voltage is the difference between the pull-up current and the pull-down current multiplied by the equivalent load resistance of the source series terminal drive circuit.

[0018] In a second aspect, the present application provides a source series terminal driving method. The source series terminal driving method includes: providing a pull-up branch and a pull-down branch of a source series terminal driving circuit, wherein, when the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the magnitude of the current flowing through the differential resistor is determined based on the current source of the pull-up branch, and when the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the magnitude of the current flowing through the differential resistor is determined based on the current source of the pull-down branch, and the output voltage of the source series terminal driving circuit is the voltage on the differential resistor; through a feedback control module of the source series terminal driving circuit, detecting the amplitude of the output voltage, comparing the amplitude of the output voltage with the amplitude of a reference voltage, and generating a current source control signal based on the difference between the amplitude of the output voltage and the amplitude of the reference voltage, wherein the current source control signal is used to control the current source of the pull-up branch when the driving voltage is high and to control the current source of the pull-down branch when the driving voltage is low, thereby adjusting the magnitude of the current flowing through the differential resistor so as to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage.

[0019] Through the second aspect of the present application, a negative feedback mechanism based on a feedback control module, using a current source of a pull-up branch and a current source of a pull-down branch, and taking the amplitude of a reference voltage as a reference, by adjusting the magnitude of the current flowing through the differential resistor, it helps to achieve an output differential voltage signal whose amplitude is equal to the amplitude of the reference voltage; in the case of low power supply voltage, additional current is introduced and the output signal amplitude is increased to an adjustable reference voltage amplitude based on a negative feedback mechanism; by keeping the common-mode voltage component of the output differential voltage signal unchanged, it helps to meet the needs of AC coupling applications, saves hardware overhead such as additional circuits for adjusting the power supply voltage, helps to flexibly adapt to the needs of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote application.

[0020] In a possible implementation manner of the second aspect of the present application, the current source of the pull-up branch and the current source of the pull-down branch are used together to keep the common-mode voltage component of the output voltage equal to the reference voltage.

[0021] In a possible implementation of the second aspect of the present application, when the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the current flowing through the differential resistor is a pull-up current; when the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the current flowing through the differential resistor is a pull-down current, and the differential-mode voltage component of the output voltage is the difference between the pull-up current and the pull-down current multiplied by the equivalent load resistance of the source series terminal drive circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of a source series terminal driving circuit according to a first implementation mode provided in an embodiment of the present application; Figure 2 A schematic diagram of a source series terminal driving circuit according to a second implementation mode provided in an embodiment of the present application; Figure 3 A schematic diagram of a source series terminal driving circuit according to a third implementation mode provided in an embodiment of the present application; Figure 4 A schematic flow chart of a source series terminal driving method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] The embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0025] It should be understood that, in the description of this application, "at least one" means one or more, and "a plurality of" means two or more. In addition, unless otherwise specified, the words "first", "second", etc. are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order.

[0026] Figure 1 This is a schematic diagram of a source series terminal driving circuit according to a first embodiment of the present application. Figure 1As shown, the source-series-terminated (SST) driving circuit includes: a pull-up branch A101 and a pull-down branch A103, wherein when the driving voltage is high, the pull-up branch A101 is turned on and the pull-down branch A103 is turned off so that the magnitude of the current flowing through the differential resistor A105 is determined based on the current source of the pull-up branch A101, and when the driving voltage is low, the pull-up branch A101 is turned off and the pull-down branch A103 is turned on so that the magnitude of the current flowing through the differential resistor A105 is determined based on the current source of the pull-down branch A103, and the output voltage of the source series terminal driving circuit is the differential resistor A101. 05; feedback control module A107, used to detect the amplitude of the output voltage, compare the amplitude of the output voltage with the amplitude of the reference voltage (reference voltage signal A130), and generate a current source control signal A132 based on the difference between the amplitude of the output voltage and the amplitude of the reference voltage (reference voltage signal A130). The current source control signal A132 is used to control the current source of the pull-up branch A101 when the driving voltage is high and the current source of the pull-down branch A103 when the driving voltage is low, thereby adjusting the current flowing through the differential resistor A105 to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage (reference voltage signal A130). Here, the driving voltage is the input differential voltage signal, that is, Figure 1 The input differential voltage signal A110 shown in FIG. 1 is composed of the positive electrode 112 of the input differential voltage signal A110 and the negative electrode 114 of the input differential voltage signal A110. The output voltage is the output differential voltage signal, that is, Figure 1 The output differential voltage signal A120 shown in FIG. 1 is composed of the positive electrode 122 of the output differential voltage signal A120 and the negative electrode 124 of the output differential voltage signal A120 .

[0027] refer to Figure 1The feedback control module A107 receives the positive electrode 122 of the output differential voltage signal A120, the negative electrode 124 of the output differential voltage signal A120, and the reference voltage signal A130, and determines the amplitude of the output voltage of the source series terminal driving circuit, that is, the amplitude of the output differential voltage signal A120, based on the positive electrode 122 of the output differential voltage signal A120 and the negative electrode 124 of the output differential voltage signal A120, thereby comparing the amplitude of the output voltage with the amplitude of the reference voltage (reference voltage signal A130), and then generating a current source control signal A132, which is used to control the current source of the pull-up branch A101 and the current source of the pull-down branch A103 in combination with the change of the driving voltage. In this way, a negative feedback mechanism is established by using the feedback control module A107. When the difference between the amplitude of the output voltage and the amplitude of the reference voltage is not zero, that is, when the amplitude of the output voltage is greater than or less than the amplitude of the reference voltage, a corresponding current source control signal A132 is generated to adjust the current flowing through the differential resistor A105, so as to achieve the purpose of reducing the difference between the amplitude of the output voltage and the amplitude of the reference voltage. For example, when the amplitude of the output voltage is greater than the amplitude of the reference voltage, the current flowing through the differential resistor A105 is reduced accordingly, so that the amplitude of the output voltage can be adjusted downward, that is, the amplitude of the output voltage is reduced, so that the amplitude of the output voltage is close to and equal to the amplitude of the reference voltage. For another example, when the amplitude of the output voltage is less than the amplitude of the reference voltage, the current flowing through the differential resistor A105 is increased accordingly, so that the amplitude of the output voltage can be adjusted upward, that is, the amplitude of the output voltage is increased, so that the amplitude of the output voltage is close to and equal to the amplitude of the reference voltage. In addition, when the difference between the amplitude of the output voltage and the amplitude of the reference voltage is larger, the degree of adjustment of the current flowing through the differential resistor A105 is also higher, which helps to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage more quickly, and helps to suppress the offset of the amplitude of the output voltage relative to the amplitude of the reference voltage.

[0028] Continue to refer Figure 1The negative feedback mechanism based on the feedback control module A107 utilizes the current source of the pull-up branch A101 and the current source of the pull-down branch A103, and uses the amplitude of the reference voltage provided by the reference voltage signal A130 as a reference. By adjusting the current flowing through the differential resistor A105, it is helpful to achieve the amplitude of the output voltage, that is, the amplitude of the output differential voltage signal A120, or the maximum output differential amplitude, equal to the amplitude of the reference voltage. In this way, when the power supply voltage is lower than the minimum voltage amplitude required by the electrical characteristics specified by the interface protocol, for example, the power supply voltage is 0.75 volts and the Peripheral Component Interconnect Express (PCIE) protocol requires a minimum voltage amplitude of 0.8 volts, the amplitude of the reference voltage can be set to 0.8 volts. In this way, by continuously detecting the difference between the amplitude of the output voltage and the amplitude of the reference voltage and making corresponding adjustments, the amplitude of the output voltage can be kept equal to the amplitude of the reference voltage, that is, 0.8 volts, thereby meeting the minimum voltage amplitude required by the electrical characteristics specified by the interface protocol. Furthermore, because the negative feedback mechanism is used to adjust the current flowing through the differential resistor A105, there is no need to increase the power supply voltage, that is, the power supply voltage can be kept lower than the minimum voltage amplitude required by the electrical characteristics specified by the interface protocol, which helps to reduce the overall power consumption. In addition, as the interface speed increases, the interface protocol may require a higher minimum voltage amplitude, such as from 0.8 volts to 1.2 volts. By setting the reference voltage amplitude to a higher value such as 1.2 volts, the output voltage amplitude can be kept equal to the reference voltage amplitude by continuously detecting the difference between the output voltage amplitude and the reference voltage amplitude and making corresponding adjustments, thereby satisfying the minimum voltage amplitude required by the electrical characteristics specified by the interface protocol. This means that in the face of different electrical characteristics required by various interface protocols, as well as the transmission rate, driving voltage and other requirements of various high-speed digital integrated circuit interfaces, the amplitude of the corresponding reference voltage can be flexibly set, thereby utilizing the above-mentioned negative feedback mechanism based on the feedback control module A107, utilizing the current source of the pull-up branch A101 and the current source of the pull-down branch A103, and taking the amplitude of the reference voltage provided by the reference voltage signal A130 as a reference, by adjusting the current flowing through the differential resistor A105, it is helpful to achieve the amplitude of the output voltage, that is, the amplitude of the output differential voltage signal A120, or the maximum output differential amplitude, which is equal to the amplitude of the reference voltage. In addition, there is no need to adjust the power supply voltage, that is, the power supply voltage can be kept at the initial setting, which saves the hardware overhead such as the additional circuit for adjusting the power supply voltage, and also reduces the complexity of the overall system, and realizes the flexible adaptation to various interface protocols and high-speed digital integrated circuit interfaces.

[0029] Continue to refer Figure 1 , a negative feedback mechanism based on the feedback control module A107, using the current source of the pull-up branch A101 and the current source of the pull-down branch A103, taking the amplitude of the reference voltage provided by the reference voltage signal A130 as a reference, and adjusting the current flowing through the differential resistor A105, helps to achieve the amplitude of the output voltage, that is, the amplitude of the output differential voltage signal A120, or the maximum output differential amplitude, equal to the amplitude of the reference voltage. In addition, by providing two current sources, that is, the current source of the pull-up branch A101 and the current source of the pull-down branch A103, the principle of generating the output voltage by the source series terminal driving circuit is combined, which helps to stabilize the common-mode voltage component of the output voltage signal, and is conducive to meeting the requirements of AC coupling applications such as PCIE interfaces that the common-mode voltage component of the transmitted signal remains unchanged. Specifically, Figure 1The source series termination driving circuit shown can achieve source impedance matching. For example, it can make the transmission line impedance equal to the driving output impedance plus the source terminal termination resistor. Through source impedance matching, output voltage shortage or signal overshoot can be avoided. The source terminal termination resistor is placed as close as possible to the driving end, that is, near the driving output, which can reduce the negative impact of signal reflection caused by impedance mismatch. The source series termination driving circuit serves as a driving stage and includes a pull-up branch A101 and a pull-down branch A103, and both branches are impedance-matched to the transmission line. For example, the resistances of both branches can be set to 50 ohms, and the differential resistor A105 is 100 ohms. In some embodiments, the pull-up branch A101 consists of a pair of Positive Channel-Metal-Oxide-Semiconductor (PMOS), that is, a PMOS transistor pair and the series resistor of the pull-up branch A101. The pull-down branch A103 consists of a pair of Negative Channel-Metal-Oxide-Semiconductor (NMOS), that is, an NMOS transistor pair and the series resistor of the pull-down branch A103. Through the driving voltage, when it is at a high level, the PMOS transistors of the pull-up branch A101 are turned on and the NMOS transistors of the pull-down branch A103 are turned off, and at this time the pull-up branch A101 works. When it is at a low level, the NMOS transistors of the pull-down branch A103 are turned on and the PMOS transistors of the pull-up branch A101 are turned off, and at this time the pull-down branch A103 works. Here, txp can be used to represent the positive pole 122 of the output differential voltage signal A120, txn can be used to represent the negative pole 124 of the output differential voltage signal A120, and vref can be used to represent the reference voltage signal A130. The pull-up branch A101 of the source series termination driving circuit as a driving stage has two current sources as one path of current source, and the pull-down branch A103 also has two current sources as the other path of current source. When (txp - txn) < vref, that is, the amplitude of the output voltage is less than the amplitude of the reference voltage, the current flowing through the differential resistor A105 is increased, which is equivalent to increasing the voltage difference across the differential resistor A105, thereby increasing txp - txn, and finally making txp - txn = vref. Conversely, when (txp - txn) > vref, that is, the amplitude of the output voltage is greater than the amplitude of the reference voltage, the current flowing through the differential resistor A105 is reduced, which is equivalent to reducing the voltage difference across the differential resistor A105, thereby reducing txp - txn, and finally making txp - txn = vref.Therefore, through the feedback control module A107, according to the deviation value of the amplitude (txp-txn) of the voltage signal output by the SST driver stage relative to the reference voltage vref, the upper and lower current sources are adjusted through the current source control signal A132, thereby increasing or decreasing the current flowing through the differential resistor A105, and then the voltage difference of the differential resistor A105 can be increased or decreased, which also increases or decreases txp-txn, and finally makes txp-txn=vref. Therefore, using the upper and lower current sources, the common-mode voltage component of the output differential voltage signal A120 can be kept unchanged and maintained as the reference voltage vref. Assuming that the driver equivalent load resistance is R, the pull-up current is Iup, and the pull-down current is Idn, the increased signal amplitude is Iup×R-Idn×R, and the common-mode voltage remains unchanged, always equal to vref. In this way, by keeping the common-mode voltage component of the output differential voltage signal A120 unchanged, it is helpful to meet the requirements of the common-mode voltage component of the transmission signal in AC coupling applications such as PCIE interfaces to remain unchanged.

[0030] Continue to refer Figure 1 , the negative feedback mechanism based on the feedback control module A107 can adopt any suitable circuit design and algorithm, as long as it can achieve the above-mentioned design purpose of suppressing the deviation of the amplitude of the output voltage relative to the amplitude of the reference voltage based on the negative feedback mechanism. In other words, the negative feedback mechanism based on the feedback control module A107, using the current source of the pull-up branch A101 and the current source of the pull-down branch A103, takes the amplitude of the reference voltage provided by the reference voltage signal A130 as a reference, and adjusts the current flowing through the differential resistor A105, which helps to achieve the amplitude of the output voltage, that is, the amplitude of the output differential voltage signal A120, or the maximum output differential amplitude, which is equal to the amplitude of the reference voltage. The amplitude detection method can provide real-time detection means through a dynamic comparator, and optionally, a static comparator can be combined to detect the static difference as a supplement to the dynamic comparator. The dynamic comparator can monitor the change of the input signal voltage amplitude in real time, so as to make real-time adjustments, and can improve the detection effect through an additional non-correlated clock signal, and timely detect the change of the input signal voltage amplitude within the detection window, so as to continuously make adjustments.

[0031] Figure 1The source series terminal driving circuit shown in the figure, through amplitude detection, uses, for example, digital-to-analog conversion technology to compare the difference of the differential transmission signal of the SST circuit, that is, the amplitude of the voltage signal output by the SST circuit, with the amplitude of the reference voltage signal, so as to achieve a negative feedback design, thereby converging the gap between the two, and realizing the locking of the amplitude of the voltage signal output by the SST circuit on the amplitude of the reference voltage signal. In this way, the electrical characteristics requirements of various interface protocols can be met by adjusting the amplitude of the reference voltage signal in combination with the requirements of the actual application environment for the output amplitude. In addition, the control voltage output by the feedback control module A107 is directly applied to the current sources of the pull-up branch A101 and the pull-down branch A103 of the SST circuit. By feeding back the voltage signal to the SST output stage, the upper and lower current sources are adjusted, thereby increasing or decreasing the current flowing through the differential resistor A105, and then the voltage difference of the differential resistor A105 can be increased or decreased, thus realizing the increase or decrease of txp-txn, and finally making txp-txn=vref. In addition, by providing two current sources, the common mode voltage can be kept unchanged. When locked, the common mode voltage is equal to the reference voltage signal amplitude. Therefore, the design of the above-mentioned SST driving circuit can not only flexibly adjust the amplitude of the output voltage signal of the SST circuit, thereby meeting the requirements of the interface protocol and the application environment for the output amplitude, but also by feeding back to the two current sources, the current flowing through the differential resistor A105 can be adjusted to keep the common mode voltage at the reference voltage, that is, the level of the reference voltage can be adjusted to adjust the level of the common mode voltage. In this way, by adjusting the amplitude of the reference voltage vref, the amplitude of the output voltage signal of the SST circuit can be adjusted, and by adjusting the level of the reference voltage vref, the level of the common mode voltage component in the output voltage signal (differential transmission signal) of the SST circuit can be changed. Furthermore, by connecting a feedback control module A107 with a negative feedback design on the output side of the SST driving circuit, such as a module for amplitude detection and control logic, it can be conveniently applied to the existing SST driving circuit. In this way, when the output amplitude of the SST driving circuit is insufficient due to low power supply voltage, additional current can be introduced to increase the output signal amplitude to the adjustable reference voltage amplitude based on the negative feedback mechanism, while retaining the existing advantages of the SST circuit, namely low power consumption.

[0032] In conclusion, Figure 1The source series terminal driving circuit shown is based on a negative feedback mechanism of the feedback control module A107, and utilizes the current source of the pull-up branch A101 and the current source of the pull-down branch A103. With the amplitude of the reference voltage provided by the reference voltage signal A130 as a reference, by adjusting the current flowing through the differential resistor A105, it helps to achieve the amplitude of the output voltage, that is, the amplitude of the output differential voltage signal A120, or the maximum output differential amplitude, which is equal to the amplitude of the reference voltage; when the output amplitude of the driving circuit is insufficient due to the low power supply voltage, additional current is introduced and the output signal amplitude is increased to the adjustable reference voltage amplitude based on the negative feedback mechanism; by keeping the common mode voltage component of the output differential voltage signal A120 unchanged, it helps to meet the needs of AC coupling applications, saves the hardware overhead such as additional circuits for adjusting the power supply voltage, helps to flexibly adapt to the needs of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote applications.

[0033] Figure 2 Schematic diagram of a source series terminal driving circuit according to a second embodiment of the present application. Figure 2 As shown, the source series terminal driving circuit includes: a pull-up branch B201 and a pull-down branch B203, wherein when the driving voltage is high, the pull-up branch B201 is turned on and the pull-down branch B203 is turned off so that the magnitude of the current flowing through the differential resistor B205 is determined based on the current source of the pull-up branch B201, and when the driving voltage is low, the pull-up branch B201 is turned off and the pull-down branch B203 is turned on so that the magnitude of the current flowing through the differential resistor B205 is determined based on the current source of the pull-down branch B203, and the output voltage of the source series terminal driving circuit is the voltage on the differential resistor B205; feedback control module B2 07, used to detect the amplitude of the output voltage, compare the amplitude of the output voltage with the amplitude of the reference voltage (reference voltage signal B230), and generate a current source control signal B232 based on the difference between the amplitude of the output voltage and the amplitude of the reference voltage (reference voltage signal B230). The current source control signal B232 is used to control the current source of the pull-up branch B201 when the driving voltage is high and the current source of the pull-down branch B203 when the driving voltage is low, thereby adjusting the current flowing through the differential resistor B205 to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage (reference voltage signal B230). Here, the driving voltage is an input differential voltage signal, that is, Figure 2 The input differential voltage signal B210 shown in FIG. 1 is composed of the positive electrode 212 of the input differential voltage signal B210 and the negative electrode 214 of the input differential voltage signal B210. The output voltage is the output differential voltage signal, that is, Figure 2The output differential voltage signal B220 formed by the positive electrode 222 of the output differential voltage signal B220 and the negative electrode 224 of the output differential voltage signal B220 as shown. Additionally, the feedback control module B207 includes: an amplitude detection module B240 for detecting the amplitude of the output voltage, comparing the amplitude of the output voltage and the amplitude of the reference voltage, and thus outputting the difference between the amplitude of the output voltage and the amplitude of the reference voltage; a digital-to-analog converter (DAC) circuit control logic B242 for generating a control signal based on the difference between the amplitude of the output voltage and the amplitude of the reference voltage; and a digital-to-analog conversion circuit B244 for generating the current source control signal B232 based on the control signal.

[0034] Figure 2 The source series termination driving circuit shown, a negative feedback mechanism based on the feedback control module B207, utilizes the current sources of the pull-up branch B201 and the pull-down branch B203, takes the amplitude of the reference voltage provided by the reference voltage signal B230 as a reference, and by adjusting the magnitude of the current flowing through the differential resistor B205, helps to achieve the amplitude of the output voltage, that is, the amplitude of the output differential voltage signal B220, or rather the maximum differential amplitude of the output, equal to the amplitude of the reference voltage; in the case of a low supply voltage resulting in insufficient output amplitude of the driving circuit, an additional current is introduced and based on the negative feedback mechanism to increase the output signal amplitude to the adjustable amplitude of the reference voltage; by keeping the common-mode voltage component of the output differential voltage signal B220 unchanged, it helps to meet the requirements of AC coupling applications, saves additional circuit hardware costs such as adjusting the supply voltage, helps to flexibly adapt to the requirements of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote the application. Additionally, through the amplitude detection module B240, the difference between the differential transmit signals (txp and txn) is detected, that is, the amplitude of the output voltage signal is detected, and compared with the reference voltage vref, the deviation value of the amplitude of the voltage signal driven by the SST output from the reference voltage can be judged in real time. According to this deviation value, the control signal output by the digital-to-analog conversion circuit control logic B242 is dynamically adjusted, thereby adjusting the output voltage signal of the digital-to-analog conversion circuit B244. The control signal output by the digital-to-analog conversion circuit control logic B242 is a digital signal, and the digital-to-analog conversion circuit B244 converts this digital signal into an analog voltage signal, that is, the output voltage signal of the digital-to-analog conversion circuit B244. When (txp - txn) < vref, the output voltage of the digital-to-analog conversion circuit B244 is increased, and conversely, the output voltage of the digital-to-analog conversion circuit B244 is decreased, ultimately making txp - txn = vref. It should be understood that Figure 2The specific structure of the feedback control module B207 shown is only exemplary. The negative feedback mechanism based on the feedback control module B207 can adopt any suitable circuit design and algorithm, as long as it can achieve the above-mentioned design purpose of suppressing the deviation of the amplitude of the output voltage relative to the amplitude of the reference voltage based on the negative feedback mechanism. In other words, the negative feedback mechanism based on the feedback control module B207, using the current source of the pull-up branch B201 and the current source of the pull-down branch B203, takes the amplitude of the reference voltage provided by the reference voltage signal B230 as a reference, and adjusts the current flowing through the differential resistor B205, which helps to achieve the amplitude of the output voltage, that is, the amplitude of the output differential voltage signal B220, or the maximum output differential amplitude, equal to the amplitude of the reference voltage.

[0035] refer to Figure 2 In a possible implementation, when the amplitude of the output voltage is less than the amplitude of the reference voltage, the output voltage of the digital-to-analog conversion circuit B244 increases based on the control signal, thereby increasing the magnitude of the current flowing through the differential resistor B205 so as to increase the magnitude of the voltage on the differential resistor B205; when the amplitude of the output voltage is greater than the amplitude of the reference voltage, the output voltage of the digital-to-analog conversion circuit B244 decreases based on the control signal, thereby reducing the magnitude of the current flowing through the differential resistor B205 so as to reduce the magnitude of the voltage on the differential resistor B205. In this way, the amplitude of the output signal of the driver can be increased under low power supply voltage to meet the electrical characteristics requirements of the interface protocol, and the power consumption can be reduced as much as possible under the condition of supporting higher interface speeds, which helps to meet the requirements of high-performance data transmission and reduced power consumption in applications such as data centers, artificial intelligence, industrial control, and smart cars.

[0036] refer to Figure 1 and Figure 2In a possible implementation, the feedback control module is used to provide a negative feedback signal relative to the difference between the amplitude of the output voltage and the amplitude of the reference voltage, and the negative feedback signal is used to adjust the magnitude of the current flowing through the differential resistor so as to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage. In this way, the negative feedback mechanism based on the feedback control module, using the current source of the pull-up branch and the current source of the pull-down branch, taking the amplitude of the reference voltage as a reference, helps to achieve the amplitude of the output differential voltage signal equal to the amplitude of the reference voltage by adjusting the magnitude of the current flowing through the differential resistor; in the case of low power supply voltage, additional current is introduced and the output signal amplitude is increased to the amplitude of the adjustable reference voltage based on the negative feedback mechanism; by keeping the common mode voltage component of the output differential voltage signal unchanged, it helps to meet the needs of AC coupling applications, saves the hardware overhead such as additional circuits for adjusting the power supply voltage, helps to flexibly adapt to the needs of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote applications.

[0037] In some embodiments, when the amplitude of the output voltage is less than the amplitude of the reference voltage, the negative feedback signal is used to increase the magnitude of the current flowing through the differential resistor so as to increase the amplitude of the voltage on the differential resistor; when the amplitude of the output voltage is greater than the amplitude of the reference voltage, the negative feedback signal is used to reduce the magnitude of the current flowing through the differential resistor so as to reduce the amplitude of the voltage on the differential resistor. In this way, the negative feedback mechanism based on the feedback control module uses the current source of the pull-up branch and the current source of the pull-down branch, takes the amplitude of the reference voltage as a reference, and adjusts the magnitude of the current flowing through the differential resistor, which helps to achieve the amplitude of the output differential voltage signal equal to the amplitude of the reference voltage; in the case of low power supply voltage, additional current is introduced and the output signal amplitude is increased to the amplitude of the adjustable reference voltage based on the negative feedback mechanism; by keeping the common mode voltage component of the output differential voltage signal unchanged, it helps to meet the needs of AC coupling applications, saves the hardware overhead such as additional circuits for adjusting the power supply voltage, helps to flexibly adapt to the needs of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote applications.

[0038] In a possible implementation, the driving voltage is an input differential voltage signal, and the output voltage is an output differential voltage signal. In this way, the negative feedback mechanism based on the feedback control module uses the current source of the pull-up branch and the current source of the pull-down branch, takes the amplitude of the reference voltage as a reference, and adjusts the current flowing through the differential resistor, which helps to achieve that the amplitude of the output differential voltage signal is equal to the amplitude of the reference voltage; in the case of low power supply voltage, additional current is introduced and the output signal amplitude is increased to the adjustable reference voltage amplitude based on the negative feedback mechanism; by keeping the common mode voltage component of the output differential voltage signal unchanged, it helps to meet the needs of AC coupling applications, saves the hardware overhead such as additional circuits for adjusting the power supply voltage, helps to flexibly adapt to the needs of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote applications.

[0039] Figure 3 A schematic diagram of a source series terminal driving circuit according to a third implementation manner provided in an embodiment of the present application. Figure 3 The basic principle of the source series terminal drive circuit shown is similar to Figure 1 The source series terminal driving circuit shown is similar and will not be described again here. Figure 3The source series terminal driving circuit shown includes: a pull-up branch and a pull-down branch, wherein, when the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the magnitude of the current flowing through the differential resistor C305 is determined based on the current source of the pull-up branch, and when the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the magnitude of the current flowing through the differential resistor C305 is determined based on the current source of the pull-down branch, and the output voltage of the source series terminal driving circuit is the voltage on the differential resistor C305; feedback control The module group C307 is used to detect the amplitude of the output voltage, compare the amplitude of the output voltage with the amplitude of the reference voltage, and generate a current source control signal C332 based on the difference between the amplitude of the output voltage and the amplitude of the reference voltage. The current source control signal C332 is used to control the current source of the pull-up branch when the driving voltage is high and the current source of the pull-down branch when the driving voltage is low, thereby adjusting the current flowing through the differential resistor C305 to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage. The driving voltage is the input differential voltage signal C310, that is, the input differential voltage signal C310 composed of the positive electrode 312 of the input differential voltage signal C310 and the negative electrode 314 of the input differential voltage signal C310. The output voltage is the output differential voltage signal C320, that is, the output differential voltage signal C320 is composed of the positive electrode 322 of the output differential voltage signal C320 and the negative electrode 324 of the output differential voltage signal C320. The amplitude of the reference voltage is determined based on the reference voltage signal C330.

[0040] refer to Figure 3 The pull-up branch includes a PMOS transistor pair. When the pull-up branch is turned on, the PMOS transistor pair is turned on. When the pull-up branch is turned off, the PMOS transistor pair is turned off. The PMOS transistor pair includes a first PMOS transistor and a second PMOS transistor. The first PMOS transistor is connected to the first end of the differential resistor C305 through a first series resistor, and the second PMOS transistor is connected to the second end of the differential resistor C305 through a second series resistor. Here, the first PMOS transistor is Figure 3 The first PMOS tube, i.e., the first series resistor corresponding to the P-type field effect tube A350, is a series resistor A355, and the corresponding current source is a current source A356, and the three electrodes of the first PMOS tube are respectively the drain electrode (load electrode) 351 of the P-type field effect tube A350, the gate electrode (control electrode) 352 of the P-type field effect tube A350, and the source electrode (bias electrode) 353 of the P-type field effect tube A350. The second PMOS tube is Figure 3As shown in the P-type field effect transistor B360, the second PMOS tube, i.e., the second series resistor corresponding to the P-type field effect transistor B360 is a series resistor B365, and the corresponding current source is a current source B366, and the three poles of the second PMOS tube are respectively the drain (load pole) 361 of the P-type field effect transistor B360, the gate (control pole) 362 of the P-type field effect transistor B360 and the source (bias pole) 363 of the P-type field effect transistor B360.

[0041] refer to Figure 3 , the pull-down branch includes an NMOS transistor pair, the NMOS transistor pair is turned on when the pull-down branch is turned on, and the NMOS transistor pair is turned off when the pull-down branch is turned off, the NMOS transistor pair includes a first NMOS transistor and a second NMOS transistor, the first NMOS transistor is connected to the first end of the differential resistor through a third series resistor, and the second NMOS transistor is connected to the second end of the differential resistor through a fourth series resistor. Here, the first NMOS transistor is Figure 3 The third series resistor corresponding to the first NMOS tube, that is, the N-type field effect tube A370, is a series resistor C375, and the corresponding current source is a current source C376, and the three electrodes of the first NMOS tube are the source electrode (load electrode) 371 of the N-type field effect tube A370, the gate electrode (control electrode) 372 of the N-type field effect tube A370, and the drain electrode (bias electrode) 373 of the N-type field effect tube A370. The second NMOS tube is Figure 3 The N-type field effect transistor B380 shown, the second NMOS tube, that is, the fourth series resistor corresponding to the second NMOS tube is the series resistor D385, and the corresponding current source is the current source D386, and the three poles of the second NMOS tube are respectively the source (load pole) 381 of the N-type field effect transistor B380, the gate (control pole) 382 of the N-type field effect transistor B380 and the drain (bias pole) 383 of the N-type field effect transistor B380. Figure 3 The power supply voltage 334 is also shown in FIG. The drain (load electrode) 351 of the P-type field effect transistor A 350 and the drain (load electrode) 361 of the P-type field effect transistor B 360 are connected to the power supply voltage 334 .

[0042] refer to Figure 3, the driving voltage is also the input differential voltage signal C310, wherein the positive electrode 312 of the input differential voltage signal C310 is connected to the gate (control electrode) 352 of the P-type field effect transistor A350 and the gate (control electrode) 372 of the N-type field effect transistor A370, and the negative electrode 314 of the input differential voltage signal C310 is connected to the gate (control electrode) 362 of the P-type field effect transistor B360 and the gate (control electrode) 382 of the N-type field effect transistor B380. In addition, the positive electrode 322 of the output differential voltage signal C320 and the negative electrode 324 of the output differential voltage signal C320 are respectively connected to the two ends of the differential resistor C305. Furthermore, the source (bias electrode) 353 of the P-type field effect transistor A350 is connected to the positive electrode 322 of the output differential voltage signal C320 via a series resistor A355, and the drain (bias electrode) 373 of the N-type field effect transistor A370 is connected to the positive electrode 322 of the output differential voltage signal C320 via a series resistor C375. The source (bias electrode) 363 of the P-type field effect transistor B360 is connected to the negative electrode 324 of the output differential voltage signal C320 via a series resistor B365, and the drain (bias electrode) 383 of the N-type field effect transistor B380 is connected to the negative electrode 324 of the output differential voltage signal C320 via a series resistor D385. In addition, the feedback control module C307 outputs the current source control signal C332 based on the positive electrode 322 of the output differential voltage signal C320, the negative electrode 324 of the output differential voltage signal C320 and the reference voltage signal C330. The current source control signal C332 is connected to the current source A356, the current source B366, the current source C376, and the current source D386. It can be seen that by controlling the current source A356, the current source B366, the current source C376, and the current source D386, the current flowing through the differential resistor C305 can be adjusted.

[0043] When the driving voltage is at a high level, the PMOS transistors (P-type field effect transistors A350 and B360) in the pull-up branch are turned on while the NMOS transistors (N-type field effect transistors A370 and B380) in the pull-down branch are turned off, and at this time the pull-up branch works; when the driving voltage is at a low level, the NMOS transistors (N-type field effect transistors A370 and B380) in the pull-down branch are turned on while the PMOS transistors (P-type field effect transistors A350 and B360) in the pull-up branch are turned off, and at this time the pull-down branch works. Here, txp can be used to represent the positive electrode 322 of the output differential voltage signal C320, txn can be used to represent the negative electrode 324 of the output differential voltage signal C320, and vref can be used to represent the reference voltage signal C330. The source series termination driver circuit has two current sources (current source A356 and current source B366) in the pull-up branch as one path of current source, and also has two current sources (current source C376 and current source D386) in the pull-down branch as the other path of current source. When (txp - txn) < vref, that is, the amplitude of the output voltage is less than the amplitude of the reference voltage, this increases the magnitude of the current flowing through the differential resistor C305, which is equivalent to increasing the voltage difference across the differential resistor C305, thereby increasing txp - txn, and finally making txp - txn = vref. Conversely, when (txp - txn) > vref, that is, the amplitude of the output voltage is greater than the amplitude of the reference voltage, this reduces the current flowing through the differential resistor C305, which is equivalent to reducing the voltage difference across the differential resistor C305, thereby reducing txp - txn, and finally making txp - txn = vref. Therefore, through the feedback control module C307, according to the deviation value of the amplitude (txp - txn) of the voltage signal output by the SST driver stage relative to the reference voltage vref in real time, through the current source control signal C332, the upper and lower two paths of current sources are adjusted, so as to increase or decrease the current flowing through the differential resistor C305, and further increase or decrease the voltage difference of the differential resistor C305, thus achieving an increase or decrease in txp - txn, and finally making txp - txn = vref. Therefore, by using the upper and lower two paths of current sources, the common-mode voltage component of the output differential voltage signal C320 can be kept unchanged and maintained at the reference voltage vref, which helps to meet the requirement in AC-coupled applications such as PCIE interfaces that the common-mode voltage component of the transmitted signal remains unchanged.

[0044] In this way, the negative feedback mechanism based on the feedback control module C307 utilizes the current source of the pull-up branch (current source A356, current source B366) and the current source of the pull-down branch (current source C376, current source D386), and takes the amplitude of the reference voltage as a reference. By adjusting the current flowing through the differential resistor C305, it helps to achieve the amplitude of the output differential voltage signal equal to the amplitude of the reference voltage; when the power supply voltage 334 is low, for example, the maximum amplitude of the power supply voltage 334 is lower than the minimum voltage amplitude specified by the interface protocol, additional current is introduced and the output signal amplitude is increased to the adjustable reference voltage amplitude based on the negative feedback mechanism; by keeping the common-mode voltage component of the output differential voltage signal unchanged, it helps to meet the needs of AC coupling applications, saves hardware overhead such as additional circuits for adjusting the power supply voltage 334, helps to flexibly adapt to the needs of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote application.

[0045] refer to Figure 3 In a possible implementation, the first series resistor and the second series resistor are used for impedance matching of the pull-up branch, and the third series resistor and the fourth series resistor are used for impedance matching of the pull-down branch. This helps to achieve impedance matching and reduce the impact of impedance mismatch.

[0046] refer to Figure 1 , Figure 2 and Figure 3 In a possible implementation, the amplitude of the reference voltage is determined based on the electrical characteristics of the interface protocol associated with the source series terminal drive circuit. This helps to flexibly adapt to the requirements of various interface protocols and high-speed digital integrated circuit interfaces.

[0047] In some embodiments, the source series terminal driving circuit utilizes the feedback control module so that the amplitude of the output voltage is equal to the amplitude of the reference voltage, wherein the amplitude of the power supply voltage of the source series terminal driving circuit is less than the amplitude of the reference voltage. Thus, when the power supply voltage is lower than the minimum voltage amplitude required by the electrical characteristics specified by the interface protocol, for example, the power supply voltage is 0.75 volts and the peripheral component interconnect express protocol requires a minimum voltage amplitude of 0.8 volts, the amplitude of the reference voltage can be set to 0.8 volts, so that by continuously detecting the difference between the amplitude of the output voltage and the amplitude of the reference voltage and making corresponding adjustments, the amplitude of the output voltage can be kept equal to the amplitude of the reference voltage, i.e., 0.8 volts, thereby satisfying the minimum voltage amplitude required by the electrical characteristics specified by the interface protocol. Furthermore, because the above-mentioned negative feedback mechanism is used to adjust the current flowing through the differential resistor, there is no need to increase the power supply voltage, i.e., the power supply voltage can be kept lower than the minimum voltage amplitude required by the electrical characteristics specified by the interface protocol, thus helping to reduce overall power consumption. In addition, as the interface speed increases, the interface protocol may require a higher minimum voltage amplitude, for example, from 0.8 volts to 1.2 volts. By setting the reference voltage amplitude to a higher value, such as 1.2 volts, the output voltage amplitude can be kept equal to the reference voltage amplitude by continuously detecting the difference between the output voltage amplitude and the reference voltage amplitude and making corresponding adjustments, thereby satisfying the minimum voltage amplitude required by the electrical characteristics specified by the interface protocol. This means that in the face of different electrical characteristics required by various interface protocols, as well as the transmission rate, drive voltage and other requirements of various high-speed digital integrated circuit interfaces, the corresponding reference voltage amplitude can be flexibly set, thereby utilizing the above-mentioned negative feedback mechanism based on the feedback control module, utilizing the current source of the pull-up branch and the current source of the pull-down branch, taking the reference voltage amplitude provided by the reference voltage signal as a reference, and adjusting the current flowing through the differential resistor, it is helpful to achieve the output voltage amplitude, that is, the amplitude of the output differential voltage signal, or the output maximum differential amplitude, equal to the reference voltage amplitude. Furthermore, there is no need to adjust the power supply voltage, that is, the power supply voltage can be kept at the initial setting, which saves the hardware overhead such as additional circuits for adjusting the power supply voltage, reduces the complexity of the overall system, and achieves flexible adaptation to various interface protocols and high-speed digital integrated circuit interface requirements.

[0048] In a possible implementation, the current source of the pull-up branch and the current source of the pull-down branch are used together to keep the common-mode voltage component of the output voltage equal to the reference voltage. In this way, by keeping the common-mode voltage component of the output differential voltage signal unchanged, it helps to meet the requirement of keeping the common-mode voltage component of the transmission signal unchanged in AC coupling applications such as PCIE interfaces.

[0049] In one possible implementation, when the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the current flowing through the differential resistor is a pull-up current; when the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the current flowing through the differential resistor is a pull-down current, and the differential-mode voltage component of the output voltage is the difference between the pull-up current and the pull-down current multiplied by the equivalent load resistance of the source series terminal drive circuit. In this way, the negative feedback mechanism based on the feedback control module utilizes the current source of the pull-up branch and the current source of the pull-down branch, takes the amplitude of the reference voltage as a reference, and adjusts the current flowing through the differential resistor, which helps to achieve the amplitude of the output differential voltage signal equal to the amplitude of the reference voltage; in the case of low power supply voltage, additional current is introduced and the output signal amplitude is increased to the adjustable reference voltage amplitude based on the negative feedback mechanism; by keeping the common-mode voltage component of the output differential voltage signal unchanged, it helps to meet the needs of AC coupling applications, saves hardware overhead such as additional circuits for adjusting the power supply voltage, helps to flexibly adapt to the needs of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote application.

[0050] Figure 4 A schematic diagram of a source series terminal driving method provided in an embodiment of the present application. Figure 4 As shown, the source series terminal driving method includes the following steps.

[0051] Step S401: providing a pull-up branch and a pull-down branch of a source series terminal driving circuit, wherein, when the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the magnitude of the current flowing through the differential resistor is determined based on the current source of the pull-up branch, and when the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the magnitude of the current flowing through the differential resistor is determined based on the current source of the pull-down branch, and the output voltage of the source series terminal driving circuit is the voltage on the differential resistor.

[0052] Step S403: Detect the amplitude of the output voltage through the feedback control module of the source series terminal driving circuit, compare the amplitude of the output voltage with the amplitude of the reference voltage, and generate a current source control signal based on the difference between the amplitude of the output voltage and the amplitude of the reference voltage, wherein the current source control signal is used to control the current source of the pull-up branch when the driving voltage is high and to control the current source of the pull-down branch when the driving voltage is low, thereby adjusting the current flowing through the differential resistor so as to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage.

[0053] Figure 4The source series terminal driving method shown is a negative feedback mechanism based on a feedback control module. It utilizes the current source of the pull-up branch and the current source of the pull-down branch. With the amplitude of the reference voltage as a reference, by adjusting the current flowing through the differential resistor, it helps to achieve the amplitude of the output differential voltage signal equal to the amplitude of the reference voltage. In the case of low power supply voltage, additional current is introduced and the output signal amplitude is increased to the amplitude of the adjustable reference voltage based on the negative feedback mechanism. By keeping the common-mode voltage component of the output differential voltage signal unchanged, it helps to meet the needs of AC coupling applications, saves hardware overhead such as additional circuits for adjusting the power supply voltage, helps to flexibly adapt to the needs of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote applications.

[0054] refer to Figure 4 In a possible implementation, the current source of the pull-up branch and the current source of the pull-down branch are used together to keep the common-mode voltage component of the output voltage equal to the reference voltage. In this way, by keeping the common-mode voltage component of the output differential voltage signal unchanged, it helps to meet the requirement of keeping the common-mode voltage component of the transmission signal unchanged in AC coupling applications such as PCIE interfaces.

[0055] In some embodiments, when the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the current flowing through the differential resistor is a pull-up current; when the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the current flowing through the differential resistor is a pull-down current, and the differential-mode voltage component of the output voltage is the difference between the pull-up current and the pull-down current multiplied by the equivalent load resistance of the source series terminal drive circuit. In this way, the negative feedback mechanism based on the feedback control module utilizes the current source of the pull-up branch and the current source of the pull-down branch, takes the amplitude of the reference voltage as a reference, and adjusts the current flowing through the differential resistor, which helps to achieve the amplitude of the output differential voltage signal equal to the amplitude of the reference voltage; in the case of low power supply voltage, additional current is introduced and the output signal amplitude is increased to the adjustable reference voltage amplitude based on the negative feedback mechanism; by keeping the common-mode voltage component of the output differential voltage signal unchanged, it helps to meet the needs of AC coupling applications, saves hardware overhead such as additional circuits for adjusting the power supply voltage, helps to flexibly adapt to the needs of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote application.

[0056] The method and device provided in the embodiments of the present application are based on the same inventive concept. Since the principles of solving the problems in the methods and devices are similar, the embodiments, implementation methods, examples or implementation methods of the methods and devices can refer to each other, and the repeated parts will not be repeated. The embodiments of the present application also provide a system, which includes multiple computing devices, and the structure of each computing device can refer to the structure of the computing device described above. The functions or operations that can be implemented by the system can refer to the specific implementation steps in the above method embodiments and / or the specific functions described in the above device embodiments, which will not be repeated here.

[0057] The present application also provides a computer-readable storage medium, in which computer instructions are stored. When the computer instructions are executed on a computer device (such as one or more processors), the method steps in the above method embodiment can be implemented. The specific implementation of the processor of the computer-readable storage medium in executing the above method steps can refer to the specific operations described in the above method embodiment and / or the specific functions described in the above device embodiment, which will not be repeated here.

[0058] It should be understood by those skilled in the art that the embodiments of the present application may be provided as methods, systems, or computer program products. The present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. The embodiments of the present application may be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented using software, the above embodiments may be implemented in whole or in part in the form of a computer program product. The present application may take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program codes. The computer program product includes one or more computer instructions. When the computer program instructions are loaded or executed on a computer, the process or function described in the embodiments of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. Computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. Computer-readable storage media can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media. Available media can be magnetic media (such as floppy disks, hard disks, tapes), optical media, or semiconductor media. Semiconductor media can be solid-state hard disks, random access memory, flash memory, read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, or any other form of suitable storage media.

[0059] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. Each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the functions specified in the process. Figure 1A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0060] In the above embodiments, the descriptions of each embodiment have their own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. The steps in the method of the embodiment of the present application can be adjusted in order, merged or deleted according to actual needs; the modules in the system of the embodiment of the present application can be divided, merged or deleted according to actual needs. If these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A source series terminal driving circuit, characterized in that: The source series terminal driving circuit comprises: A pull-up branch and a pull-down branch, wherein when the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the magnitude of the current flowing through the differential resistor is determined based on the current source of the pull-up branch, and when the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the magnitude of the current flowing through the differential resistor is determined based on the current source of the pull-down branch, and the output voltage of the source series terminal driving circuit is the voltage on the differential resistor; A feedback control module is used to detect the amplitude of the output voltage, compare the amplitude of the output voltage with the amplitude of a reference voltage, and generate a current source control signal based on the difference between the amplitude of the output voltage and the amplitude of the reference voltage, wherein the current source control signal is used to control the current source of the pull-up branch when the driving voltage is high and to control the current source of the pull-down branch when the driving voltage is low, thereby adjusting the current flowing through the differential resistor to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage.

2. The source series terminal driving circuit according to claim 1, characterized in that: The feedback control module comprises: an amplitude detection module, used for detecting the amplitude of the output voltage, comparing the amplitude of the output voltage with the amplitude of the reference voltage, and outputting the difference between the amplitude of the output voltage and the amplitude of the reference voltage; a digital-to-analog conversion circuit control logic for generating a control signal based on a difference between the magnitude of the output voltage and the magnitude of the reference voltage; The digital-to-analog conversion circuit is used to generate the current source control signal based on the control signal.

3. The source series terminal driving circuit according to claim 2, characterized in that: When the amplitude of the output voltage is smaller than the amplitude of the reference voltage, the output voltage of the digital-to-analog conversion circuit increases based on the control signal, thereby increasing the current flowing through the differential resistor so as to increase the amplitude of the voltage on the differential resistor; when the amplitude of the output voltage is greater than the amplitude of the reference voltage, the output voltage of the digital-to-analog conversion circuit decreases based on the control signal, thereby reducing the current flowing through the differential resistor so as to reduce the amplitude of the voltage on the differential resistor.

4. The source series terminal driving circuit according to claim 1, characterized in that: The feedback control module is used to provide a negative feedback signal relative to the difference between the amplitude of the output voltage and the amplitude of the reference voltage, and the negative feedback signal is used to adjust the current flowing through the differential resistor so as to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage.

5. The source series terminal driving circuit according to claim 4, characterized in that: When the amplitude of the output voltage is smaller than the amplitude of the reference voltage, the negative feedback signal is used to increase the current flowing through the differential resistor so as to increase the amplitude of the voltage on the differential resistor; when the amplitude of the output voltage is greater than the amplitude of the reference voltage, the negative feedback signal is used to reduce the current flowing through the differential resistor so as to reduce the amplitude of the voltage on the differential resistor.

6. The source series terminal driving circuit according to claim 1, characterized in that: The driving voltage is an input differential voltage signal, and the output voltage is an output differential voltage signal.

7. The source series terminal driving circuit according to claim 1, characterized in that: The pull-up branch includes a PMOS tube pair, which is turned on when the pull-up branch is turned on, and is turned off when the pull-up branch is turned off. The PMOS tube pair includes a first PMOS tube and a second PMOS tube, the first PMOS tube is connected to the first end of the differential resistor through a first series resistor, and the second PMOS tube is connected to the second end of the differential resistor through a second series resistor.

8. The source series terminal driving circuit according to claim 7, characterized in that: The pull-down branch includes an NMOS tube pair, which is turned on when the pull-down branch is turned on, and is turned off when the pull-down branch is turned off. The NMOS tube pair includes a first NMOS tube and a second NMOS tube, the first NMOS tube is connected to the first end of the differential resistor through a third series resistor, and the second NMOS tube is connected to the second end of the differential resistor through a fourth series resistor.

9. The source series terminal driving circuit according to claim 8, characterized in that: The first series resistor and the second series resistor are used for impedance matching of the pull-up branch, and the third series resistor and the fourth series resistor are used for impedance matching of the pull-down branch.

10. The source series terminal driving circuit according to claim 1, characterized in that: The magnitude of the reference voltage is determined based on electrical characteristic provisions of an interface protocol associated with the source series terminal drive circuit.

11. The source series terminal driving circuit according to claim 10, characterized in that: The source series terminal driving circuit utilizes the feedback control module so that the amplitude of the output voltage is equal to the amplitude of the reference voltage, wherein the amplitude of the power supply voltage of the source series terminal driving circuit is smaller than the amplitude of the reference voltage.

12. The source series terminal driving circuit according to claim 1, characterized in that: The current source of the pull-up branch and the current source of the pull-down branch are used together to maintain the common mode voltage component of the output voltage equal to the reference voltage.

13. The source series terminal driving circuit according to claim 1, characterized in that: When the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the current flowing through the differential resistor is a pull-up current. When the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the current flowing through the differential resistor is a pull-down current. The differential-mode voltage component of the output voltage is the difference between the pull-up current and the pull-down current multiplied by the equivalent load resistance of the source series terminal drive circuit.

14. A source series terminal driving method, characterized in that: The source series terminal driving method comprises: Providing a pull-up branch and a pull-down branch of a source series terminal driving circuit, wherein when the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the magnitude of the current flowing through the differential resistor is determined based on the current source of the pull-up branch, and when the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the magnitude of the current flowing through the differential resistor is determined based on the current source of the pull-down branch, and the output voltage of the source series terminal driving circuit is the voltage on the differential resistor; The amplitude of the output voltage is detected by the feedback control module of the source series terminal driving circuit, the amplitude of the output voltage is compared with the amplitude of the reference voltage, and a current source control signal is generated based on the difference between the amplitude of the output voltage and the amplitude of the reference voltage, wherein the current source control signal is used to control the current source of the pull-up branch when the driving voltage is high and to control the current source of the pull-down branch when the driving voltage is low, thereby adjusting the current flowing through the differential resistor so as to reduce the difference between the amplitude of the output voltage and the amplitude of the reference voltage.

15. The source series terminal driving method according to claim 14, characterized in that: The current source of the pull-up branch and the current source of the pull-down branch are used together to maintain the common mode voltage component of the output voltage equal to the reference voltage.

16. The source series terminal driving method according to claim 14, characterized in that: When the driving voltage is high, the pull-up branch is turned on and the pull-down branch is turned off so that the current flowing through the differential resistor is a pull-up current. When the driving voltage is low, the pull-up branch is turned off and the pull-down branch is turned on so that the current flowing through the differential resistor is a pull-down current. The differential-mode voltage component of the output voltage is the difference between the pull-up current and the pull-down current multiplied by the equivalent load resistance of the source series terminal drive circuit.

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