A swing enhanced voltage mode driver

Abstract

The application discloses a swing enhancement type voltage mode driver and belongs to the technical field of integrated circuits. The driver comprises a driving switch, a controllable matching impedance and a swing enhancement module. The controllable matching impedance is adjusted in resistance value by a single controllable impedance MOS tube and a DAC, and replaces a traditional large-scale MOS array to save area. The swing enhancement module adopts a cascode current source structure, is controlled by the DAC to inject a current, and improves output swing without changing a power supply voltage and without destroying impedance matching. The application is suitable for various characteristic impedance transmission protocols, has stable output common-mode voltage, is suitable for a SERDES chip of 28 nm and below CMOS process, and has the advantages of low power consumption, small area and strong driving capacity.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit technology, and more particularly to a swing-enhanced voltage-mode driver. Background Technology

[0002] As a key circuit module of high-speed serial interfaces, voltage-mode drivers transmit digital baseband signals into the channel by controlling the gate of a switching transistor to either fully conduct or cut off. Their core strength lies in achieving fast setup speeds while maintaining low power consumption to meet high-speed requirements, and also satisfying impedance matching requirements.

[0003] In the prior art, the output swing of voltage-mode drivers is limited by impedance matching. Under ideal impedance matching conditions, the output swing is limited to half of the power supply voltage to ground, which limits its driving capability. Summary of the Invention

[0004] The main objective of this invention is to provide a swing-enhanced voltage-mode driver, which aims to solve the existing technical problems.

[0005] To achieve the above objectives, the present invention provides a swing-enhanced voltage-mode driver, characterized in that it comprises: The drive switch module includes a first drive switch and a second drive switch, used to receive differential digital signals and convert them into voltage signals for output to the transmission channel; An adjustable matching impedance module includes a first adjustable matching impedance and a second adjustable matching impedance, which are respectively connected between the drive switch module and the power supply and ground, and are used to adjust the output impedance of the driver to match the characteristic impedance of the transmission channel. The swing enhancement module includes a first swing enhancement module and a second swing enhancement module, which are respectively connected between the output terminal of the drive switch module and the power supply and ground, and are connected to the control terminal of the drive switch module. They are used to inject adjustable current into the corresponding branch according to the input signal state to enhance the voltage swing of the output signal while maintaining impedance matching and without changing the power supply voltage.

[0006] Furthermore, the first interface of the first adjustable matching impedance is connected to the first power supply, and its second interface is connected to the second interface of the first drive switch and the second drive switch. The first interface of the second adjustable matching impedance is connected to ground, and its second interface is connected to the third interface of the first drive switch and the second drive switch. The third interface of the first swing enhancement module is connected to the second power supply, its first interface is connected to the fourth interface of the first drive switch and the first interface of the second swing enhancement module, and its second interface is connected to the fourth interface of the second drive switch and the second interface of the second swing enhancement module. The third interface of the second amplitude enhancement module is connected to ground, its fourth interface is connected to the fourth interface of the first amplitude enhancement module and the first interface of the first drive switch, and its fifth interface is connected to the fourth interface of the first amplitude enhancement module and the first interface of the second drive switch.

[0007] Furthermore, the drive switch module includes a drive switch transistor and a fixed matching resistor; The first driving switch is composed of a first MOSFET, a second MOSFET, and a first resistor: the first MOSFET and the second MOSFET are driving switch transistors, and the first resistor is a fixed matching resistor; the gates of the first MOSFET and the second MOSFET are connected to each other, serving as the first interface of the first driving switch; the drains of the first MOSFET and the second MOSFET are both connected to the first resistor; the source of the first MOSFET serves as the second interface of the first driving switch, the source of the second MOSFET serves as the third interface of the first driving switch, and the other end of the first resistor serves as the fourth interface of the first driving switch. The second driving switch consists of a third MOSFET, a fourth MOSFET, and a second resistor: the third MOSFET and the fourth MOSFET are driving switch transistors, and the second resistor is a fixed matching resistor; the gates of the third MOSFET and the fourth MOSFET are connected, serving as the first interface of the second driving switch; the drains of the third MOSFET and the fourth MOSFET are both connected to the second resistor; the source of the third MOSFET serves as the second interface of the second driving switch, the source of the fourth MOSFET serves as the third interface of the second driving switch, and the other end of the second resistor serves as the fourth interface of the second driving switch.

[0008] Furthermore, the swing enhancement module includes an IDAC, a current distribution switch, and a current source; The first swing enhancement module consists of a first IDAC, a seventh MOSFET, an eighth MOSFET, an eleventh MOSFET, and a twelfth MOSFET: the seventh and eighth MOSFETs form a current source, and the eleventh and twelfth MOSFETs are current distribution switches; the source of the seventh MOSFET serves as the third interface of the first swing enhancement module, the drain of the seventh MOSFET is connected to the source of the eighth MOSFET, and the drain of the eighth MOSFET is connected to the sources of both the eleventh and twelfth MOSFETs; the gates of both the seventh and eighth MOSFETs are connected to the output terminal of the first IDAC; the gate of the eleventh MOSFET serves as the fourth interface of the first swing enhancement module, and the drain of the eleventh MOSFET serves as the first interface of the first swing enhancement module; the gate of the twelfth MOSFET serves as the fifth interface of the first swing enhancement module, and the drain of the twelfth MOSFET serves as the second interface of the first swing enhancement module; the input terminal of the first IDAC serves as the sixth interface of the first swing enhancement module. The second swing enhancement module consists of a second IDAC, a ninth MOSFET, a tenth MOSFET, a thirteenth MOSFET, and a fourteenth MOSFET: the ninth and tenth MOSFETs form a current source, and the thirteenth and fourteenth MOSFETs are current distribution switches; the source of the tenth MOSFET serves as the third interface of the second swing enhancement module, the drain of the tenth MOSFET is connected to the source of the ninth MOSFET, and the drain of the ninth MOSFET is connected to the sources of both the thirteenth and fourteenth MOSFETs; the gates of both the ninth and tenth MOSFETs are connected to the output terminal of the second IDAC; the gate of the thirteenth MOSFET serves as the fourth interface of the second swing enhancement module, and the drain of the thirteenth MOSFET serves as the first interface of the second swing enhancement module; the gate of the fourteenth MOSFET serves as the fifth interface of the second swing enhancement module, and the drain of the fourteenth MOSFET serves as the second interface of the second swing enhancement module; the input terminal of the second IDAC serves as the sixth interface of the second swing enhancement module.

[0009] Furthermore, the adjustable matching impedance includes a controllable resistance MOSFET, an additional fixed resistor, and a termDAC; The first adjustable matching impedance consists of a first termDAC, a fifth MOSFET, and a third resistor: the fifth MOSFET is a controllable resistance MOSFET, and the third resistor is an additional fixed resistor; the source of the fifth MOSFET is connected to one end of the third resistor, serving as the first interface of the first adjustable matching impedance; the drain of the fifth MOSFET is connected to the other end of the third resistor, serving as the second interface of the first adjustable matching impedance; the gate of the fifth MOSFET is connected to the output terminal of the first termDAC, and the input terminal of the first termDAC serves as the third interface of the first adjustable matching impedance. The second adjustable matching impedance consists of a second termDAC, a sixth MOSFET, and a fourth resistor: the sixth MOSFET is a controllable resistance MOSFET, and the fourth resistor is an additional fixed resistor; the source of the sixth MOSFET is connected to one end of the fourth resistor, serving as the first interface of the second adjustable matching impedance; the drain of the sixth MOSFET is connected to the other end of the fourth resistor, serving as the second interface of the second adjustable matching impedance; the gate of the sixth MOSFET is connected to the output terminal of the second termDAC, and the input terminal of the second termDAC serves as the third interface of the second adjustable matching impedance.

[0010] Furthermore, the IDAC is a four-bit input current steering DAC, which contains five current sources of different sizes, with the sizes increasing in a doubling relationship. The output current can be adjusted within the range of 1 to 16 times the reference current.

[0011] Furthermore, the termDAC is a 10-bit input resistive DAC with an R-2R structure, and its output can be 2¹ within the power supply voltage range. 0Resolution adjustment.

[0012] Furthermore, the current source in the swing enhancement module adopts a cascode structure; The current source of the first swing enhancement module is composed of the seventh MOS transistor and the eighth MOS transistor connected in a common source and common gate configuration, and the current source of the second swing enhancement module is composed of the ninth MOS transistor and the tenth MOS transistor connected in a common source and common gate configuration.

[0013] Furthermore, the first power supply is a fixed voltage source or a low-dropout linear regulator, and the second power supply is a high-potential power supply used to provide the operating voltage for the current source of the swing enhancement module.

[0014] Furthermore, the expression for the output swing of the driver is: ; in, Adjustable current provided for the swing enhancement module This is the characteristic impedance of the transmission line.

[0015] The beneficial effects of this invention are reflected in: This invention can increase the swing amplitude of the transmitter according to the final requirements without disrupting impedance matching or changing the power supply voltage, thus overcoming the limitation of swing amplitude in traditional voltage-mode drivers.

[0016] This invention abandons the large-scale impedance matching array of traditional SST drivers and uses an adjustable matching impedance consisting of a MOSFET with a gate voltage controlled by a DAC and a fixed resistor in parallel to set the matching impedance of the driver, thereby saving area and increasing MOSFET utilization.

[0017] Specifically, in this invention, the characteristic impedance of the transmission line is first measured. The inputs of the first and second term DACs are adjusted based on this characteristic impedance, thereby changing the gate voltages of the fifth and sixth MOSFETs. The on-resistance formula for MOSFETs operating in the linear region is then used. It can be seen that this ultimately changed the on-resistance of the fifth MOSFET. and the on-resistance of the sixth MOSFET Ultimately, this makes the resistance ( ∥ + ∥ The characteristic impedance of the current rudder DAC is consistent with that of the transmission line, thus achieving impedance matching. When transmitting data, the output swing needs to be increased according to the transmission requirements. The current source in the swing enhancement module can be changed by changing the input value of the current rudder DAC. The current rudder DAC has a total of 4 bits of input and 16 different levels. Attached Figure Description

[0018] Figure 1 This is a structural diagram of an existing conventional voltage-mode driver; Figure 2 This is a structural diagram of the equivalent model of an existing traditional voltage-mode driver; Figure 3 A structural diagram of a swing-enhanced voltage-mode driver provided by the present invention; Figure 4 A circuit diagram of an amplitude-enhanced voltage-mode driver provided by the present invention; Figure 5 A structural diagram of the drive switch provided by the present invention; Figure 6 The structural diagram of the adjustable matching impedance module provided by the present invention; Figure 7 This is a structural diagram of the swing amplitude enhancement module provided by the present invention; Figure 8 An equivalent model of an amplitude-enhanced voltage-mode driver is provided by the present invention; Figure 9 A schematic diagram of the improved voltage-mode driver provided by the present invention applied to the TX section of a SERDES. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 As shown, traditional voltage-mode drivers mainly have two architectures. Figure 1 The impedance matching of the voltage-mode driver shown is mainly controlled by the upper and lower connected MOSFET arrays connected to the two driving switches. Taking the input signal as "1" as an example, the n-channel switch is turned on and the p-channel switch is turned off, because the MOSFET array is mainly composed of SEL. <n:0>The MOSFET is controlled by a digital selection signal, so its operating state is either fully on or fully off. When fully on, it operates in the deep linear region. Taking NMOS as an example, the on-resistance of each on-state MOSFET is... Assuming that m of the n-channel MOSFETs in the impedance matching array are selected to be turned on, then the total high-pass impedance of the MOSFET array is: .

[0021] Specifically, assuming the switching transistor is fully turned on, its on-resistance is: The equivalent circuit diagram of this method is as follows: Figure 2 As shown, the matching impedance of the driver at this time is The drawbacks of this method are that it requires a large number of MOSFETs to form the impedance matching array, and many MOSFETs are in a turned-off state when driving transmission protocols with high matching impedances, resulting in wasted area and the introduction of large parasitic capacitances between the impedance matching network and the switching transistors. Furthermore, under the condition of satisfying impedance matching, because... Therefore, the power supply voltage at this time is and Since the voltage supplied is consistent, the final output swing is limited to [value missing]. superior.

[0022] Based on the aforementioned shortcomings of the existing technology, please refer to Figure 3 The present invention provides a swing-enhanced voltage-mode driver, including a drive switch, a swing-enhancing module, and an adjustable matching impedance; The drive switch converts the input digital signal into an instantaneous voltage signal and transmits it to the channel; the swing enhancement module enhances the driver output swing under the condition of satisfying impedance matching and without changing the power supply voltage, thus freeing it from the limitations of traditional voltage-mode drivers; the adjustable matching impedance adjusts the driver's matching internal impedance to match the characteristic impedance of the transmission line, ensuring that the signal is not reflected and enhancing signal integrity.

[0023] Specifically, the drive switch includes a first drive switch and a second drive switch, which are used to convert differential digital signals into voltage signals and send them to the transmission channel; The adjustable matching impedance module includes a first adjustable matching impedance and a second adjustable matching impedance, which are used to adjust the matching internal impedance of the driver to adapt to transmission lines with different characteristic impedances. The swing enhancement module includes a first swing enhancement module and a second swing enhancement module, which are used to increase the output signal swing without changing the power supply voltage and without breaking the impedance matching. Specifically, the first interface of the first adjustable matching impedance is connected to the first power supply, and its second interface is connected to the second interfaces of the first drive switch and the second drive switch; the first interface of the second adjustable matching impedance is connected to ground, and its second interface is connected to the third interfaces of the first drive switch and the second drive switch; the third interface of the first swing enhancement module is connected to the second power supply, and its first interface is connected to the fourth interface of the first drive switch and the first interface of the second swing enhancement module, and its second interface is connected to the fourth interface of the second drive switch and the second interface of the second swing enhancement module; the third interface of the second swing enhancement module is connected to ground, its fourth interface is connected to the fourth interface of the first swing enhancement module and the first interface of the first drive switch, and its fifth interface is connected to the fourth interface of the first swing enhancement module and the first interface of the second drive switch.

[0024] In this embodiment, the first power supply is a fixed voltage source or a low-dropout linear regulator, and the second power supply is a high-potential power supply used to provide the operating voltage for the current source of the swing enhancement module.

[0025] For details, please refer to Figure 5 In one embodiment, the first driving switch is composed of a first MOSFET, a second MOSFET, and a first resistor: the first MOSFET and the second MOSFET are driving switch transistors, and the first resistor is a fixed matching resistor; the gates of the first MOSFET and the second MOSFET are connected to each other, serving as the first interface of the first driving switch; the drains of the first MOSFET and the second MOSFET are both connected to the first resistor; the source of the first MOSFET serves as the second interface of the first driving switch, the source of the second MOSFET serves as the third interface of the first driving switch, and the other end of the first resistor serves as the fourth interface of the first driving switch; The second driving switch consists of a third MOSFET, a fourth MOSFET, and a second resistor: the third and fourth MOSFETs are driving switch transistors, and the second resistor is a fixed matching resistor; the gates of the third and fourth MOSFETs are connected, serving as the first interface of the second driving switch; the drains of both the third and fourth MOSFETs are connected to the second resistor; the source of the third MOSFET serves as the second interface of the second driving switch, the source of the fourth MOSFET serves as the third interface of the second driving switch, and the other end of the second resistor serves as the fourth interface of the second driving switch.

[0026] Figure 5 In the diagram, the gates of the first and second MOSFETs are connected together to transmit the signal Dm, and the gates of the third and fourth MOSFETs are connected together to transmit the signal Dp. Their function is that when a differential digital signal needs to be transmitted, for example when Dm = 0 and Dp = 1, the first and fourth MOSFETs are turned on, while the second and third MOSFETs are turned off. The signal travels through the first MOSFET to channel 1, through the receiver to channel 2, and then through the fourth MOSFET to ground, forming a path. At this point, the signal will be transmitted. Conversely, when Dm="1" and Dp="0", the same analysis applies.

[0027] Please see Figure 7 In one embodiment, the swing enhancement module includes an IDAC, a current distribution switch, and a current source; the first swing enhancement module is composed of a first IDAC, a seventh MOSFET, an eighth MOSFET, an eleventh MOSFET, and a twelfth MOSFET: the seventh MOSFET and the eighth MOSFET constitute the current source, and the eleventh MOSFET and the twelfth MOSFET are current distribution switches; the source of the seventh MOSFET serves as the third interface of the first swing enhancement module, the drain of the seventh MOSFET is connected to the source of the eighth MOSFET, and the drain of the eighth MOSFET is connected to the sources of both the eleventh and twelfth MOSFETs; the gates of both the seventh and eighth MOSFETs are connected to the output terminal of the first IDAC; the gate of the eleventh MOSFET serves as the fourth interface of the first swing enhancement module, and the drain of the eleventh MOSFET serves as the first interface of the first swing enhancement module; the gate of the twelfth MOSFET serves as the fifth interface of the first swing enhancement module, and the drain of the twelfth MOSFET serves as the second interface of the first swing enhancement module; the input terminal of the first IDAC serves as the sixth interface of the first swing enhancement module. The second swing enhancement module consists of a second IDAC, a ninth MOSFET, a tenth MOSFET, a thirteenth MOSFET, and a fourteenth MOSFET: the ninth and tenth MOSFETs form a current source, and the thirteenth and fourteenth MOSFETs are current distribution switches; the source of the tenth MOSFET serves as the third interface of the second swing enhancement module, the drain of the tenth MOSFET is connected to the source of the ninth MOSFET, and the drain of the ninth MOSFET is connected to the sources of both the thirteenth and fourteenth MOSFETs; the gates of both the ninth and tenth MOSFETs are connected to the output of the second IDAC; the gate of the thirteenth MOSFET serves as the fourth interface of the second swing enhancement module, and the drain of the thirteenth MOSFET serves as the first interface of the second swing enhancement module; the gate of the fourteenth MOSFET serves as the fifth interface of the second swing enhancement module, and the drain of the fourteenth MOSFET serves as the second interface of the second swing enhancement module; the input of the second IDAC serves as the sixth interface of the second swing enhancement module.

[0028] In this embodiment, the IDAC is a four-bit input current steering DAC, which contains five current sources of different sizes, with the size increasing by a factor of two. The output current can be adjusted within the range of 1 to 16 times the reference current.

[0029] In this embodiment, the current source in the swing enhancement module adopts a cascode structure; wherein, the current source of the first swing enhancement module is composed of the seventh MOS transistor and the eighth MOS transistor connected in a common source and common gate configuration, and the current source of the second swing enhancement module is composed of the ninth MOS transistor and the tenth MOS transistor connected in a common source and common gate configuration.

[0030] Figure 7 In this circuit, the IDAC is controlled by four input terminals. The first IDAC is controlled by pboost<3:0>, and the second IDAC is controlled by nboost<3:0>. The outputs of the two IDACs provide bias to the current sources, namely the seventh and eighth MOSFETs and the ninth and tenth MOSFETs, which act as cascode current sources, to generate the required current. The eleventh, twelfth, thirteenth, and fourteenth MOSFETs act as current distribution switches, mainly to select the appropriate branch to supply current according to the different input signals in order to enhance the final output swing.

[0031] Please see Figure 6 In one embodiment, the adjustable matching impedance includes a controllable resistance MOSFET, an additional fixed resistor, and a termDAC; the first adjustable matching impedance is composed of a first termDAC, a fifth MOSFET, and a third resistor: the fifth MOSFET is a controllable resistance MOSFET, and the third resistor is an additional fixed resistor; the source of the fifth MOSFET is connected to one end of the third resistor, serving as the first interface of the first adjustable matching impedance; the drain of the fifth MOSFET is connected to the other end of the third resistor, serving as the second interface of the first adjustable matching impedance; the gate of the fifth MOSFET is connected to the output terminal of the first termDAC, and the input terminal of the first termDAC serves as the third interface of the first adjustable matching impedance; The second adjustable matching impedance consists of a second termDAC, a sixth MOSFET, and a fourth resistor: the sixth MOSFET is a controllable resistance MOSFET, and the fourth resistor is an additional fixed resistor; the source of the sixth MOSFET is connected to one end of the fourth resistor, serving as the first interface of the second adjustable matching impedance; the drain of the sixth MOSFET is connected to the other end of the fourth resistor, serving as the second interface of the second adjustable matching impedance; the gate of the sixth MOSFET is connected to the output of the second termDAC, and the input of the second termDAC serves as the third interface of the second adjustable matching impedance.

[0032] In this embodiment, the term DAC is a 10-bit input resistive DAC with an R-2R structure, and its output can be 2¹ within the power supply voltage range. 0 Resolution adjustment.

[0033] Figure 6 In this configuration, the term DAC is controlled by 10 inputs. The first term DAC is controlled by pterm<9:0>, and the second term DAC is controlled by nterm<9:0>. The outputs of the two term DACs control the gate voltages of the fifth and sixth MOSFETs, thereby changing their on-resistance. This causes the matching impedance of the driver to change to adapt to the characteristic impedance of the transmission line. Assuming the on-resistance of the driver switch is negligible, and the third and fourth resistors are set as... The on-resistance of the fifth and sixth MOSFETs is ,refer to Figure 5 Fixed resistor when transmitting signals , Connected in series in the circuit as part of the matching impedance, assuming the first and second resistors are... Then the matching impedance of the driver is By changing the input of the term DAC, and thus its output, the gate voltage of the fifth and sixth MOSFETs can be controlled, thereby changing their on-resistance. This can change the matching impedance of the driver. This allows it to adapt to transmission lines with different characteristic impedances.

[0034] In one embodiment, the first, third, fifth, seventh, eighth, eleventh, and twelfth MOSFETs are all P-channel MOSFETs; the second, fourth, sixth, ninth, tenth, thirteenth, and fourteenth MOSFETs are all N-channel MOSFETs.

[0035] Please see Figure 4 This diagram illustrates a specific circuit diagram of a swing-enhanced voltage-mode driver, where the gates of the first and second MOSFETs are connected together and connected to the gates of the eleventh and thirteenth MOSFETs for the input signal Dm; the gates of the third and fourth MOSFETs are connected together and connected to the gates of the twelfth and fourteenth MOSFETs for the input signal Dp. First, given the characteristic impedance of the transmission line, the input codes of the nterm<9:0> and pterm<9:0> buses are adjusted. The value is adjusted so that the matching internal impedance of the driver is consistent with that of the transmission line. When a large increase in output swing is required, the input codes of the two buses, nboost<3:0> and pboost<3:0>, need to be set so that the final swing can be swung to the required amplitude.

[0036] Please see Figure 8 An equivalent circuit diagram of a swing-enhanced voltage-mode driver is shown, such as... Figure 8 As shown in the left figure, assuming Dm="0", Dp="1", and the impedance matching condition is already met, the characteristic impedance of the transmission line is assumed to be... The driver matching impedance is , Figure 4 The current values ​​of the two cascode current sources composed of the seventh, eighth, ninth, and tenth MOSFETs are assumed to be... and ,in and This forms a circuit with a accompanying current source. If we perform Norton-Thevenin circuit equivalence on it, it can be transformed into... Figure 8 As shown in the right figure, the output swing at this time is... for: Since the impedance matching condition has been met, therefore... And assume At this point, the swing amplitude can be further simplified to: The amplitude enhancement module can change The value of the current source ultimately changes the output swing. Furthermore, the typical value of the small-signal AC resistance of the cascode current source is several hundred kΩ, while the typical values ​​of the transmission line characteristic impedance and the driver matching internal resistance are much smaller than this, so the resistance they introduce in parallel with the driver is negligible.

[0037] For details, please refer to Figure 8 A swing-enhanced voltage-mode driver, characterized in that, due to the use of two parallel swing-enhancing modules, the final output common-mode value will be stabilized at... Therefore, there is no need to design a common-mode hold circuit, and the receiver does not need to set a new decision threshold when the swing is amplified.

[0038] Please see Figure 9 An embodiment of an amplitude-enhanced voltage-mode driver is presented, which is a TX interface circuit of SERSE, including: a tree-structured serializer, a TX divider module, a DCC module, a delay unit, a thermometer decoder module, and an SST driver composed of the amplitude-enhanced voltage-mode driver of this invention. The serializer mainly converts the parallel 20-bit signal into a serial digital signal, and the clock signal required by the serializer mainly comes from the TX divider module. During this period, the DCC module calibrates the clock duty cycle. The serialized digital signal is delayed three times to obtain three different digital signals named pre, main, and post, and then input. The input is fed into an SST driver composed of swing-enhanced voltage-mode drivers. Assuming the driver consists of 45 slices, a thermometer decoder is used to select these slices to transmit different signals. For example, 25 slices are selected to transmit the main signal, 10 slices to transmit the pre signal, and the remaining 10 slices are selected to transmit the pre signal. Finally, appropriate nterm<9:0> and pterm<9:0> are selected to achieve impedance matching. Furthermore, appropriate nboost<3:0> and pboost<3:0> are set to enhance the final output swing, swinging the final single-ended output swing to... On a higher swing amplitude.

[0039] It should be noted that if the embodiments of the present invention involve directional indicators such as (up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0040] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, "multiple" refers to two or more. Moreover, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A swing-enhanced voltage-mode driver, characterized in that... ,include: The drive switch module includes a first drive switch and a second drive switch, used to receive differential digital signals and convert them into voltage signals for output to the transmission channel; An adjustable matching impedance module includes a first adjustable matching impedance and a second adjustable matching impedance, which are respectively connected between the drive switch module and the power supply and ground, and are used to adjust the output impedance of the driver to match the characteristic impedance of the transmission channel. The swing enhancement module includes a first swing enhancement module and a second swing enhancement module, which are respectively connected between the output terminal of the drive switch module and the power supply and ground, and are connected to the control terminal of the drive switch module. They are used to inject adjustable current into the corresponding branch according to the input signal state to enhance the voltage swing of the output signal while maintaining impedance matching and without changing the power supply voltage.

2. The swing-enhanced voltage-mode driver as described in claim 1, characterized in that: The first interface of the first adjustable matching impedance is connected to the first power supply, and its second interface is connected to the second interface of the first drive switch and the second drive switch. The first interface of the second adjustable matching impedance is connected to ground, and its second interface is connected to the third interface of the first drive switch and the second drive switch. The third interface of the first swing enhancement module is connected to the second power supply, its first interface is connected to the fourth interface of the first drive switch and the first interface of the second swing enhancement module, and its second interface is connected to the fourth interface of the second drive switch and the second interface of the second swing enhancement module. The third interface of the second amplitude enhancement module is connected to ground, its fourth interface is connected to the fourth interface of the first amplitude enhancement module and the first interface of the first drive switch, and its fifth interface is connected to the fourth interface of the first amplitude enhancement module and the first interface of the second drive switch.

3. The swing-enhanced voltage-mode driver as described in claim 1, characterized in that: The drive switch module includes a drive switch transistor and a fixed matching resistor; The first driving switch is composed of a first MOSFET, a second MOSFET, and a first resistor: the first MOSFET and the second MOSFET are driving switch transistors, and the first resistor is a fixed matching resistor; the gates of the first MOSFET and the second MOSFET are connected to each other, serving as the first interface of the first driving switch; the drains of the first MOSFET and the second MOSFET are both connected to the first resistor; the source of the first MOSFET serves as the second interface of the first driving switch, the source of the second MOSFET serves as the third interface of the first driving switch, and the other end of the first resistor serves as the fourth interface of the first driving switch. The second driving switch consists of a third MOSFET, a fourth MOSFET, and a second resistor: the third MOSFET and the fourth MOSFET are driving switch transistors, and the second resistor is a fixed matching resistor; the gates of the third MOSFET and the fourth MOSFET are connected, serving as the first interface of the second driving switch; the drains of the third MOSFET and the fourth MOSFET are both connected to the second resistor; the source of the third MOSFET serves as the second interface of the second driving switch, the source of the fourth MOSFET serves as the third interface of the second driving switch, and the other end of the second resistor serves as the fourth interface of the second driving switch.

4. The swing-enhanced voltage-mode driver as described in claim 1, characterized in that: The swing enhancement module includes an IDAC, a current distribution switch, and a current source; The first swing enhancement module consists of a first IDAC, a seventh MOSFET, an eighth MOSFET, an eleventh MOSFET, and a twelfth MOSFET: the seventh and eighth MOSFETs form a current source, and the eleventh and twelfth MOSFETs are current distribution switches; the source of the seventh MOSFET serves as the third interface of the first swing enhancement module, the drain of the seventh MOSFET is connected to the source of the eighth MOSFET, and the drain of the eighth MOSFET is connected to the sources of both the eleventh and twelfth MOSFETs; the gates of both the seventh and eighth MOSFETs are connected to the output terminal of the first IDAC; the gate of the eleventh MOSFET serves as the fourth interface of the first swing enhancement module, and the drain of the eleventh MOSFET serves as the first interface of the first swing enhancement module; the gate of the twelfth MOSFET serves as the fifth interface of the first swing enhancement module, and the drain of the twelfth MOSFET serves as the second interface of the first swing enhancement module; the input terminal of the first IDAC serves as the sixth interface of the first swing enhancement module. The second swing enhancement module consists of a second IDAC, a ninth MOSFET, a tenth MOSFET, a thirteenth MOSFET, and a fourteenth MOSFET: the ninth and tenth MOSFETs form a current source, and the thirteenth and fourteenth MOSFETs are current distribution switches; the source of the tenth MOSFET serves as the third interface of the second swing enhancement module, the drain of the tenth MOSFET is connected to the source of the ninth MOSFET, and the drain of the ninth MOSFET is connected to the sources of both the thirteenth and fourteenth MOSFETs; the gates of both the ninth and tenth MOSFETs are connected to the output terminal of the second IDAC; the gate of the thirteenth MOSFET serves as the fourth interface of the second swing enhancement module, and the drain of the thirteenth MOSFET serves as the first interface of the second swing enhancement module; the gate of the fourteenth MOSFET serves as the fifth interface of the second swing enhancement module, and the drain of the fourteenth MOSFET serves as the second interface of the second swing enhancement module; the input terminal of the second IDAC serves as the sixth interface of the second swing enhancement module.

5. The swing-enhanced voltage-mode driver as described in claim 1, characterized in that: The adjustable matching impedance includes a controllable resistance MOSFET, an additional fixed resistor, and a termDAC; The first adjustable matching impedance consists of a first termDAC, a fifth MOSFET, and a third resistor: the fifth MOSFET is a controllable resistance MOSFET, and the third resistor is an additional fixed resistor; the source of the fifth MOSFET is connected to one end of the third resistor, serving as the first interface of the first adjustable matching impedance; the drain of the fifth MOSFET is connected to the other end of the third resistor, serving as the second interface of the first adjustable matching impedance; the gate of the fifth MOSFET is connected to the output terminal of the first termDAC, and the input terminal of the first termDAC serves as the third interface of the first adjustable matching impedance. The second adjustable matching impedance consists of a second termDAC, a sixth MOSFET, and a fourth resistor: the sixth MOSFET is a controllable resistance MOSFET, and the fourth resistor is an additional fixed resistor; the source of the sixth MOSFET is connected to one end of the fourth resistor, serving as the first interface of the second adjustable matching impedance; the drain of the sixth MOSFET is connected to the other end of the fourth resistor, serving as the second interface of the second adjustable matching impedance; the gate of the sixth MOSFET is connected to the output terminal of the second termDAC, and the input terminal of the second termDAC serves as the third interface of the second adjustable matching impedance.

6. The swing-enhanced voltage-mode driver as described in claim 4, characterized in that: The IDAC is a four-bit input current steering DAC, which contains five current sources of different sizes, increasing in a doubling relationship. The output current can be adjusted within the range of 1 to 16 times the reference current.

7. The swing-enhanced voltage-mode driver as described in claim 5, characterized in that: The termDAC is a 10-bit input resistive DAC, employing an R-2R structure, and its output can be 2¹ within the power supply voltage range. 0 Resolution adjustment.

8. The swing-enhanced voltage-mode driver as described in claim 3, characterized in that: The current source in the swing enhancement module adopts a cascode structure; The current source of the first swing enhancement module is composed of the seventh MOS transistor and the eighth MOS transistor connected in a common source and common gate configuration, and the current source of the second swing enhancement module is composed of the ninth MOS transistor and the tenth MOS transistor connected in a common source and common gate configuration.

9. The swing-enhanced voltage-mode driver as described in claim 2, characterized in that: The first power supply is a fixed voltage source or a low-dropout linear regulator, and the second power supply is a high-potential power supply used to provide the operating voltage for the current source of the swing enhancement module.

10. A swing-enhanced voltage-mode driver as described in any one of claims 1-9, characterized in that: The expression for the output swing of the driver is: ； in, Adjustable current provided for the swing enhancement module This is the characteristic impedance of the transmission line.

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