Source series terminal driving circuit and source series terminal driving method

Abstract

The present application relates to the field of integrated circuit technology and provides a source series terminal driving circuit and a source series terminal driving method. The source series terminal driving circuit uses a negative feedback mechanism based on a feedback control module, utilizes a current source of a pull-up branch and a current source of a pull-down branch, and uses the amplitude of a reference voltage as a reference to adjust the current flowing through a differential resistor, thereby helping to achieve an output differential voltage signal amplitude equal to the amplitude of the reference voltage; in the case of low power supply voltage, additional current is introduced and the negative feedback mechanism is used to increase the output signal amplitude to the amplitude of an adjustable reference voltage; by maintaining the common-mode voltage component of the output differential voltage signal unchanged, it helps to meet the requirements of AC coupling applications, saves hardware overhead such as additional circuits for adjusting the power supply voltage, helps to flexibly adapt to the requirements of various interface protocols and high-speed digital integrated circuit interfaces, and helps to promote application.

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] High-speed digital integrated circuit applications, such as data centers, artificial intelligence, industrial control, and smart cars, require increasingly higher interface speeds to meet high-performance data transmission requirements. As interface speeds increase, power consumption becomes a key consideration in integrated circuit design. Existing current-mode logic (CML) drivers used to build high-speed digital communication interfaces suffer from high static power consumption and strict termination voltage restrictions. Using source-series-terminated (SST) drivers to build high-speed digital communication interfaces presents the problem of the SST driver's output voltage amplitude being half the supply voltage. When the supply voltage is low, the driver's output voltage amplitude may not meet the electrical characteristics requirements of the interface protocol, hindering data transmission performance. Existing source-series-terminated drivers, driver circuits, and driver schemes increase the output signal amplitude by increasing the supply voltage, resulting in a significant increase in power consumption, especially as interface speeds increase. This does not meet the power consumption requirements of 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 driver's output signal 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, helping to meet the high-performance data transmission and power consumption reduction requirements of 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 includes: a pull-up branch and a pull-down branch, wherein when a 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; 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; the output voltage of the source series terminal driving circuit is the voltage across the differential resistor; and a feedback control module, configured 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 amplitudes of the output voltage and the reference voltage, the current source control signal being 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 to reduce the difference between the amplitudes of the output voltage and the reference voltage.

[0005] Through the first aspect of the present application, a negative feedback mechanism based on a feedback control module utilizes a current source of a pull-up branch and a current source of a pull-down branch, and takes 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 applications.

[0006] In a possible implementation of the first aspect of the present application, the feedback control module includes: an amplitude detection module, 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, 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, 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 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 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 less than the amplitude of the reference voltage.

[0016] In a possible implementation 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 maintain 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 a 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 a current source of the pull-up branch; 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; the output voltage of the source series terminal driving circuit is the voltage across the differential resistor; detecting the amplitude of the output voltage through a feedback control module of the source series terminal driving circuit, 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 amplitudes of the output voltage and 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 to reduce the difference between the amplitudes of the output voltage and the reference voltage.

[0019] Through the second aspect of the present application, a negative feedback mechanism based on a feedback control module utilizes a current source of a pull-up branch and a current source of a pull-down branch, and takes 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 a negative feedback mechanism is used to increase the output signal amplitude to an adjustable reference voltage amplitude; 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.

[0020] In a possible implementation 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 maintain 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 following is a brief introduction to the drawings required for use in the description of the embodiments. 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 any creative work.

[0023] Figure 1 A schematic diagram of a source series terminal driving circuit according to a first embodiment of the present application;

[0024] Figure 2 A schematic diagram of a source series terminal driving circuit according to a second embodiment of the present application;

[0025] Figure 3 A schematic diagram of a source series terminal driving circuit according to a third embodiment of the present application;

[0026] Figure 4 A flow chart of a source series terminal driving method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

[0028] It should be understood that, in the description of this application, "at least one" means one or more, and "a plurality" means two or more. In addition, unless otherwise specified, the terms "first" and "second" are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or order.

[0029] Figure 1 This is a schematic diagram of a source series terminal driving circuit according to the 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; 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; the output voltage of the source-series-terminated driving circuit is the magnitude of the current flowing through the differential resistor A105. 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 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 .

[0030] refer to Figure 1The feedback control module A107 receives the positive electrode 122 and 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 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 for controlling 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 manner, a negative feedback mechanism is established 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, 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. 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 correspondingly reduced, thereby adjusting downward, i.e., reducing, the amplitude of the output voltage so that the amplitude of the output voltage approaches and equals 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 correspondingly increased, thereby adjusting upward, i.e., increasing, the amplitude of the output voltage so that the amplitude of the output voltage approaches and equals 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 greater, the degree of adjustment of the current flowing through the differential resistor A105 is also greater, 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.

[0031] Continue to refer Figure 1A negative feedback mechanism based on feedback control module A107 utilizes the current source of pull-up branch A101 and the current source of pull-down branch A103, using the reference voltage amplitude provided by reference voltage signal A130 as a reference. By adjusting the current flowing through differential resistor A105, the output voltage amplitude, i.e., the amplitude of output differential voltage signal A120, or the maximum output differential amplitude, is equal to the reference voltage amplitude. Thus, if the power supply voltage is lower than the minimum voltage amplitude required for electrical characteristics specified by the interface protocol, for example, if 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 reference voltage amplitude can be set to 0.8 volts. By continuously detecting the difference between the output voltage amplitude and the reference voltage amplitude and making corresponding adjustments, the output voltage amplitude can be maintained equal to the reference voltage amplitude, i.e., 0.8 volts, thereby meeting the minimum voltage amplitude required for electrical characteristics specified by the interface protocol. Furthermore, because the aforementioned negative feedback mechanism is utilized to adjust the current flowing through the differential resistor A105, there is no need to increase the power supply voltage. In other words, the power supply voltage can remain below the minimum voltage amplitude required for the electrical characteristics specified by the interface protocol, thereby helping to reduce overall power consumption. Furthermore, as interface speeds increase, 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, and continuously detecting the difference between the output voltage amplitude and the reference voltage amplitude and making corresponding adjustments, the output voltage amplitude can be maintained equal to the reference voltage amplitude, thereby meeting the minimum voltage amplitude required for the electrical characteristics specified by the interface protocol. This means that, in response to the varying electrical characteristics required by various interface protocols, as well as the transmission rate and drive voltage requirements of various high-speed digital integrated circuit interfaces, the corresponding reference voltage amplitude can be flexibly set. This allows the aforementioned negative feedback mechanism based on feedback control module A107 to be utilized. By utilizing the current source of pull-up branch A101 and the current source of pull-down branch A103, and using the reference voltage amplitude provided by reference voltage signal A130 as a reference, the current flowing through differential resistor A105 can be adjusted to help achieve an output voltage amplitude, i.e., the amplitude of output differential voltage signal A120, or in other words, a maximum output differential amplitude, equal to the reference voltage amplitude. Furthermore, there is no need to adjust the power supply voltage; the power supply voltage can be maintained at its initial setting. This eliminates the hardware overhead of additional circuitry for power supply voltage adjustment, reduces overall system complexity, and enables flexible adaptation to various interface protocols and high-speed digital integrated circuit interface requirements.

[0032] Continue to refer Figure 1 The negative feedback mechanism based on feedback control module A107 utilizes the current source of pull-up branch A101 and the current source of pull-down branch A103, and uses the amplitude of the reference voltage provided by reference voltage signal A130 as a reference. By adjusting the current flowing through 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, equal to the amplitude of the reference voltage. In addition, by providing two current sources, namely the current source of pull-up branch A101 and the current source of pull-down branch A103, this combines the principle of generating output voltage by the source series terminal drive circuit, helps 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 require the common-mode voltage component of the transmitted signal to remain unchanged. Specifically, Figure 1The source series termination driving circuit shown can achieve source impedance matching, for example, making the transmission line impedance equal to the driving output impedance plus the source terminal termination resistor. Through source impedance matching, insufficient output voltage 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 P-type metal oxide semiconductors (Positive Channel-Metal-Oxide-Semiconductor, PMOS), that is, a PMOS transistor pair and the series resistor of the pull-up branch A101, and the pull-down branch A103 consists of a pair of N-type metal oxide semiconductors (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 represent the positive pole 122 of the output differential voltage signal A120, txn can represent the negative pole 124 of the output differential voltage signal A120, and vref can 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, feedback control module A107 adjusts the upper and lower current sources in real time based on the deviation of the amplitude (txp-txn) of the voltage signal output by the SST driver stage relative to the reference voltage vref, using current source control signal A132. This increases or decreases the current flowing through differential resistor A105, thereby increasing or decreasing the voltage difference across differential resistor A105, thereby increasing or decreasing txp-txn, ultimately achieving txp-txn=vref. Therefore, utilizing the upper and lower current sources, the common-mode voltage component of the output differential voltage signal A120 can be maintained constant and maintained at the reference voltage vref. Assuming 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 x R - Idn x R, while the common-mode voltage remains unchanged, always equal to vref. Maintaining the common-mode voltage component of the output differential voltage signal A120 thus helps meet the requirement for a constant common-mode voltage component of the transmit signal in AC-coupled applications, such as PCIE interfaces.

[0033] Continue to refer Figure 1 The negative feedback mechanism based on feedback control module A107 can employ any suitable circuit design and algorithm, as long as it achieves the aforementioned design objective of suppressing the deviation of the output voltage amplitude relative to the reference voltage amplitude through the negative feedback mechanism. In other words, the negative feedback mechanism based on feedback control module A107 utilizes the current source of pull-up branch A101 and the current source of pull-down branch A103, using the reference voltage amplitude provided by reference voltage signal A130 as a reference. By adjusting the current flowing through differential resistor A105, the output voltage amplitude, i.e., the amplitude of output differential voltage signal A120, or the maximum output differential amplitude, is equal to the reference voltage amplitude. A dynamic comparator can provide real-time detection. Optionally, a static comparator can be combined to detect static differential values as a supplement to the dynamic comparator. The dynamic comparator can monitor changes in the input signal voltage amplitude in real time, enabling real-time adjustments. Additional uncorrelated clock signals can be used to improve detection performance, enabling timely detection of changes in the input signal voltage amplitude within the detection window, allowing for continuous adjustments.

[0034] Figure 1The illustrated source series termination driver circuit uses amplitude detection, such as digital-to-analog conversion technology, to compare the difference between the differential transmit signals of the SST circuit, i.e., the amplitude of the voltage signal output by the SST circuit, with the amplitude of a reference voltage signal. This achieves a negative feedback design, thereby narrowing the gap between the two and locking the amplitude of the voltage signal output by the SST circuit to the reference voltage signal. This allows the reference voltage signal amplitude to be adjusted to meet the electrical characteristics of various interface protocols, based on the output amplitude requirements of actual applications. Furthermore, the control voltage output by 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. The voltage signal fed back to the SST output stage regulates the upper and lower current sources, thereby increasing or decreasing the current flowing through the differential resistor A105. This, in turn, increases or decreases the voltage difference across the differential resistor A105, thereby increasing or decreasing txp-txn, ultimately achieving txp-txn=vref. Furthermore, by providing two upper and lower current sources, the common-mode voltage can be maintained constant. When locked, the common-mode voltage is equal to the reference voltage signal amplitude. Therefore, the aforementioned SST driver circuit design not only allows for flexible adjustment of the amplitude of the SST circuit's output voltage signal to meet the output amplitude requirements of the interface protocol and application environment, but also maintains the common-mode voltage at the reference voltage by feeding back to the upper and lower current sources to adjust the current flowing through differential resistor A105. In other words, the level of the common-mode voltage can be adjusted by adjusting the reference voltage level. Thus, by adjusting the amplitude of the reference voltage vref, the amplitude of the SST circuit's output voltage signal can be adjusted, and by adjusting the level of the reference voltage vref, the level of the common-mode voltage component in the SST circuit's output voltage signal (differential transmit signal) can be varied. Moreover, by connecting a feedback control module A107 with a negative feedback design to 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 power supply voltage is low and the output amplitude of the SST driving circuit is insufficient, additional current can be introduced to increase the output signal amplitude to the amplitude of the adjustable reference voltage based on the negative feedback mechanism, while retaining the existing advantages of the SST circuit, namely low power consumption.

[0035] In short, Figure 1The source series terminal drive circuit shown uses a 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 helps to achieve the output voltage amplitude, 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. When the low power supply voltage causes the output amplitude of the drive circuit to be insufficient, additional current is introduced and the negative feedback mechanism is used to increase the output signal amplitude to the amplitude of the adjustable reference voltage. By maintaining the common-mode voltage component of the output differential voltage signal A120 unchanged, it helps to meet the requirements of AC coupling applications, saves hardware overhead such as additional circuits for adjusting the power supply voltage, and helps to flexibly adapt to the requirements of various interface protocols and high-speed digital integrated circuit interfaces, which helps to promote application.

[0036] Figure 2 This is a 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; 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 across the differential resistor B205; feedback control module B2 07, is 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 the input differential voltage signal, that is, Figure 2 The input differential voltage signal B210 shown in FIG 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. In addition, 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 with 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.

[0037] Figure 2 The source series termination driver circuit shown, a negative feedback mechanism based on the feedback control module B207, uses 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 output maximum differential amplitude, equal to the amplitude of the reference voltage; in the case of a low supply voltage resulting in insufficient output amplitude of the driver 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. In addition, 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 feedback control module B207 shown is for illustrative purposes only. The negative feedback mechanism based on feedback control module B207 can employ any suitable circuit design and algorithm, as long as it achieves the aforementioned design objective of suppressing the deviation of the output voltage amplitude relative to the reference voltage amplitude through the negative feedback mechanism. In other words, the negative feedback mechanism based on feedback control module B207 utilizes the current source of pull-up branch B201 and the current source of pull-down branch B203, and uses the amplitude of the reference voltage provided by reference voltage signal B230 as a reference. By adjusting the current flowing through differential resistor B205, the negative feedback mechanism helps achieve an output voltage amplitude, i.e., the amplitude of output differential voltage signal B220, or in other words, a maximum output differential amplitude, equal to the amplitude of the reference voltage.

[0038] refer to Figure 2 In one 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 and increasing the magnitude of the voltage across 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 decreasing the magnitude of the current flowing through the differential resistor B205 and decreasing the magnitude of the voltage across the differential resistor B205. In this way, the amplitude of the driver's output signal can be increased at a low power supply voltage to meet the electrical characteristics requirements of the interface protocol. Furthermore, power consumption can be minimized while supporting higher interface speeds, helping 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.

[0039] refer to Figure 1 and Figure 2In one possible embodiment, the feedback control module is configured 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 configured to adjust the magnitude of 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. Thus, the negative feedback mechanism based on the feedback control module utilizes a current source in the pull-up branch and a current source in the pull-down branch, and uses the amplitude of the reference voltage as a reference to adjust the magnitude of the current flowing through the differential resistor, thereby helping to achieve an 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 negative feedback mechanism is used to increase the amplitude of the output signal to the amplitude of the adjustable reference voltage. By maintaining the common-mode voltage component of the output differential voltage signal unchanged, the system helps meet the requirements of AC coupling applications, saves hardware overhead such as additional circuitry for adjusting the power supply voltage, and facilitates flexible adaptation to various interface protocols and high-speed digital integrated circuit interface requirements, thus promoting widespread application.

[0040] 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 current flowing through the differential resistor to increase the amplitude of the voltage across 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 decrease the current flowing through the differential resistor to decrease the amplitude of the voltage across the differential resistor. Thus, the 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, and using the amplitude of the reference voltage as a reference, helps achieve an output differential voltage signal with an amplitude equal to the amplitude of the reference voltage by adjusting the current flowing through the differential resistor. In the case of low power supply voltage, additional current is introduced and the negative feedback mechanism is used to increase the output signal amplitude to the amplitude of the adjustable reference voltage. By maintaining the common-mode voltage component of the output differential voltage signal unchanged, the system helps meet the requirements of AC coupling applications, saves hardware overhead such as additional circuitry for adjusting the power supply voltage, and facilitates flexible adaptation to various interface protocols and high-speed digital integrated circuit interface requirements, thus promoting widespread application.

[0041] In one possible embodiment, the driving voltage is an input differential voltage signal, and the output voltage is an output differential voltage signal. Thus, a negative feedback mechanism based on a feedback control module utilizes a current source in a pull-up branch and a current source in a pull-down branch, uses the amplitude of a reference voltage as a reference, and adjusts the current flowing through the differential resistor, thereby helping to achieve an output differential voltage signal amplitude equal to the reference voltage amplitude. In the case of low power supply voltage, additional current is introduced and the negative feedback mechanism is used to increase the output signal amplitude to the adjustable reference voltage amplitude. By maintaining the common-mode voltage component of the output differential voltage signal unchanged, the system helps meet the requirements of AC coupling applications, saves hardware overhead such as additional circuitry for adjusting the power supply voltage, and facilitates flexible adaptation to various interface protocols and high-speed digital integrated circuit interface requirements, thereby promoting widespread application.

[0042] Figure 3 This is a schematic diagram of a source series terminal driving circuit according to a third embodiment of the present application. Figure 3 The basic principle of the source series terminal drive circuit shown is the same as Figure 1 The source series terminal drive 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; 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; the output voltage of the source series terminal driving circuit is the voltage across the differential resistor C305; feedback control The module C307 is configured 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 C332 based on the difference between the amplitudes of the output voltage and the reference voltage. The current source control signal C332 is configured 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 amplitudes of the output voltage and the reference voltage. The driving voltage is the input differential voltage signal C310, i.e., the input differential voltage signal C310 formed by 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.

[0043] 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 In the P-type field effect transistor A350 shown in FIG, the first PMOS transistor, namely the P-type field effect transistor A350, has a first series resistor A355 corresponding thereto, and a current source A356 corresponding thereto. In addition, the three electrodes of the first PMOS transistor are the drain (load electrode) 351 of the P-type field effect transistor A350, the gate (control electrode) 352 of the P-type field effect transistor A350, and the source (bias electrode) 353 of the P-type field effect transistor A350. The second PMOS transistor is Figure 3As shown in the P-type field effect transistor B360, the second PMOS transistor, that is, 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 transistor are 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.

[0044] refer to Figure 3 The pull-down branch includes an NMOS transistor pair. When the pull-down branch is turned on, the NMOS transistor pair is turned on. When the pull-down branch is turned off, the NMOS transistor pair 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 In the N-type field effect transistor A370 shown in FIG, the third series resistor corresponding to the first NMOS transistor, namely the N-type field effect transistor A370, is a series resistor C375, and the corresponding current source is a current source C376. In addition, the three electrodes of the first NMOS transistor are the source electrode (load electrode) 371 of the N-type field effect transistor A370, the gate electrode (control electrode) 372 of the N-type field effect transistor A370, and the drain electrode (bias electrode) 373 of the N-type field effect transistor A370. The second NMOS transistor is Figure 3 As shown in the N-type field effect transistor B380, the second NMOS transistor, that is, the fourth series resistor corresponding to the second NMOS transistor is the series resistor D385, and the corresponding current source is the current source D386, and the three poles of the second NMOS transistor are 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 Also shown is a power supply voltage 334 . The drain (load) 351 of the P-type field effect transistor A 350 and the drain (load) 361 of the P-type field effect transistor B 360 are connected to the power supply voltage 334 .

[0045] refer to Figure 3The driving voltage is also referred to as the input differential voltage signal C310. 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, while 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. Furthermore, the positive electrode 322 and the negative electrode 324 of the output differential voltage signal C320 are connected to the two ends of the differential resistor C305, respectively. Furthermore, the source (bias) 353 of 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. The drain (bias) 373 of 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) 363 of 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. The drain (bias) 383 of 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. Furthermore, the feedback control module C307 outputs a 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. As can be seen, 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.

[0046] When the driving voltage is at a high level, the PMOS transistors (P-type field effect transistors A350 and P-type field effect transistors B360) in the pull-up branch are turned on while the NMOS transistors (N-type field effect transistors A370 and N-type field effect transistors 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 N-type field effect transistors B380) in the pull-down branch are turned on while the PMOS transistors (P-type field effect transistors A350 and P-type field effect transistors 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 pole 322 of the output differential voltage signal C320, txn can be used to represent the negative pole 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.

[0047] 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 negative feedback mechanism is used to increase the output signal amplitude to the amplitude of the adjustable reference voltage; by maintaining 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.

[0048] refer to Figure 3 In one possible implementation, the first and second series resistors are used for impedance matching of the pull-up branch, and the third and fourth series resistors are used for impedance matching of the pull-down branch. This helps achieve impedance matching and reduces the impact of impedance mismatch.

[0049] refer to Figure 1 、 Figure 2 and Figure 3 In one 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 driver circuit. This facilitates flexible adaptation to various interface protocols and high-speed digital integrated circuit interface requirements.

[0050] In some embodiments, the source series terminal driver circuit utilizes the feedback control module to ensure 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 driver circuit is less than the amplitude of the reference voltage. Thus, if the power supply voltage is lower than the minimum voltage amplitude required for electrical characteristics specified by the interface protocol, for example, if the power supply voltage is 0.75 volts and the PCI Express protocol requires a minimum voltage amplitude of 0.8 volts, the reference voltage amplitude can be set to 0.8 volts. By continuously detecting the difference between the output voltage amplitude and the reference voltage amplitude and making corresponding adjustments, the output voltage amplitude can be maintained equal to the reference voltage amplitude, i.e., 0.8 volts, thereby meeting the minimum voltage amplitude required for electrical characteristics specified by the interface protocol. Furthermore, because the negative feedback mechanism described above is utilized to adjust the current flowing through the differential resistor, the power supply voltage does not need to be increased; that is, the power supply voltage can remain below the minimum voltage amplitude required for electrical characteristics specified by the interface protocol, thereby reducing overall power consumption. Furthermore, as interface speeds increase, interface protocols 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 maintained 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 meeting the minimum voltage amplitude required for the electrical characteristics specified by the interface protocol. This means that, in response to the different electrical characteristics required by various interface protocols, as well as the transmission rate and drive voltage requirements of various high-speed digital integrated circuit interfaces, the reference voltage amplitude can be flexibly set accordingly. By utilizing the negative feedback mechanism based on the feedback control module, the current source of the pull-up branch and the current source of the pull-down branch, using the reference voltage amplitude provided by the reference voltage signal as a reference, and adjusting the current flowing through the differential resistor, the output voltage amplitude, i.e., the amplitude of the output differential voltage signal, or in other words, the maximum output differential amplitude, can be 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 realizes the flexible adaptation of various interface protocols and high-speed digital integrated circuit interface requirements.

[0051] In one possible implementation, 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. Thus, by maintaining the common-mode voltage component of the output differential voltage signal unchanged, it helps meet the requirement of maintaining the common-mode voltage component of the transmitted signal in AC-coupled applications, such as PCIE interfaces.

[0052] In one possible embodiment, 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 and a negative feedback mechanism are introduced to increase the output signal amplitude to the amplitude of the adjustable reference voltage; 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.

[0053] Figure 4 This is a flow chart 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.

[0054] 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; 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; the output voltage of the source series terminal driving circuit is the voltage across the differential resistor.

[0055] Step S403: Detecting the amplitude of the output voltage through the feedback control module of the source series terminal drive circuit, comparing the amplitude of the output voltage with the amplitude of the 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 drive voltage is high and to control the current source of the pull-down branch when the drive 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.

[0056] Figure 4The source series terminal driving method shown is a negative feedback mechanism based on a feedback control module. It utilizes a current source of a pull-up branch and a current source of a pull-down branch. With the amplitude of the 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 amplitude 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 applications.

[0057] refer to Figure 4 In one possible implementation, 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. By maintaining the common-mode voltage component of the output differential voltage signal unchanged, this helps meet the requirement of maintaining the common-mode voltage component of the transmitted signal in AC-coupled applications, such as PCIE interfaces.

[0058] 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; 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 and a negative feedback mechanism are introduced to increase the output signal amplitude to the amplitude of the adjustable reference voltage; 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.

[0059] The methods and devices provided in the embodiments of the present application are based on the same inventive concept. Since the principles of the methods and devices for solving problems 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, and will not be repeated here.

[0060] The present application also provides a computer-readable storage medium storing computer instructions. When the computer instructions are executed on a computer device (e.g., one or more processors), the method steps described in the above method embodiments can be implemented. The specific implementation of the above method steps by the processor of the computer-readable storage medium can refer to the specific operations described in the above method embodiments and / or the specific functions described in the above device embodiments, and will not be further described here.

[0061] Those skilled in the art will appreciate 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 an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. The embodiments of the present application may be implemented in whole or in part via software, hardware, firmware, or any other combination. When implemented using software, the above embodiments may be implemented in whole or in part as 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 code. The computer program product comprises one or more computer instructions. When loaded or executed on a computer, the computer program instructions fully or partially perform the processes or functions described in the embodiments of the present application. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via 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 a collection of one or more available media. Available media can be magnetic media (such as floppy disks, hard disks, or magnetic tape), optical media, or semiconductor media. Semiconductor media can be solid-state drives, random access memory, flash memory, read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, or any other suitable storage medium.

[0062] 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 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 produce 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 the instruction device, which implements the function 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, thereby providing instructions for implementing the process in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0063] In the above embodiments, the descriptions of each embodiment have different emphases. 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 sequence, 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 drive circuit, characterized in that: The source series terminal driving circuit 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 is determined based on the current source of the pull-up branch; 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 across the differential resistor; a feedback control module, configured 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 amplitudes of the output voltage and the reference voltage, wherein the current source control signal is configured 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 to reduce the difference between the amplitudes of the output voltage and the reference voltage. The driving voltage is an input differential voltage signal, the output voltage is an output differential voltage signal, the amplitude of the output voltage is the output maximum differential amplitude of the output differential voltage signal, and 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 differential voltage signal equal to the reference voltage.

2. The source series terminal driving circuit according to claim 1, characterized in that: The feedback control module includes: an amplitude detection module, configured to detect the amplitude of the output voltage, compare the amplitude of the output voltage with the amplitude of the reference voltage, and thereby output a 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 configured 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, wherein: 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 across 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 across the differential resistor.

6. The source series terminal driving circuit according to claim 1, characterized in that: 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 through a first series resistor, and the second PMOS transistor is connected to the second end of the differential resistor through a second series resistor.

7. The source series terminal driving circuit according to claim 6, characterized in that: The pull-down branch includes an NMOS transistor pair. When the pull-down branch is turned on, the NMOS transistor pair is turned on, and when the pull-down branch is turned off, the NMOS transistor pair 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.

8. The source series terminal driving circuit according to claim 7, 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.

9. The source series terminal driving circuit according to claim 1, wherein: 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.

10. The source series terminal driving circuit according to claim 9, characterized in that: The source series terminal driving circuit utilizes the feedback control module to make the amplitude of the output voltage 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.

11. The source series terminal driving circuit according to claim 1, 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 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.

12. A source series terminal driving method, characterized in that: The source series terminal driving method includes: A pull-up branch and a pull-down branch of a source series terminal driving circuit are provided, 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; 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 across the differential resistor; The feedback control module of the source series terminal drive circuit detects the amplitude of the output voltage, compares the amplitude of the output voltage with the amplitude of a reference voltage, and generates a current source control signal based on the difference between the amplitudes of the output voltage and the reference voltage, wherein the current source control signal is used to control the current source of the pull-up branch when the drive voltage is high and to control the current source of the pull-down branch when the drive voltage is low, thereby adjusting the magnitude of 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. The driving voltage is an input differential voltage signal, the output voltage is an output differential voltage signal, the amplitude of the output voltage is the output maximum differential amplitude of the output differential voltage signal, and 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 differential voltage signal equal to the reference voltage.

13. The source series terminal driving method according to claim 12, 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 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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