Resistance adjustment circuit and resistance adjustment method

Abstract

The present application belongs to the field of resistance adjustment technology, and specifically relates to a resistance adjustment circuit and a resistance adjustment method. The resistance adjustment circuit includes a controller, a resistor array selection module, a reference voltage adjustment module, a reference voltage comparison module and an adjustment voltage determination module; the reference voltage adjustment module outputs a corresponding reference voltage according to the impedance requirement of the load end; the reference voltage comparison module compares a first reference voltage with the voltage on the pull-down resistor array, so that the controller adjusts the resistance value of the pull-down resistor array according to the voltage comparison result; the adjustment voltage determination module outputs a corresponding adjustment voltage according to the comparison result of the second reference voltage and the voltage on the pull-up resistor array, so that the controller adjusts the resistance value of the pull-up resistor array according to the adjustment voltage; the present application adjusts the resistance of the pull-up resistor array and the pull-down resistor array at the signal source end through the impedance of the load end, thereby achieving impedance matching between the signal source end and the load end, with high adjustment accuracy and strong flexibility.

Description

Technical Field

[0001] The present application belongs to the field of resistance adjustment technology, and specifically relates to a resistance adjustment circuit and a resistance adjustment method. Background Art

[0002] In high-speed signal transmission, the impedance mismatch between the signal source and the load will cause the signal to be reflected on the transmission line. This is because the transmission line can be regarded as a "waveguide", and the signal will be affected by the impedance during the transmission process. When the signal encounters an impedance mismatch, part of the signal will be reflected back to the source, while the other part of the signal will continue to be transmitted forward. When this reflected signal is superimposed on the original signal, it will change the waveform of the signal, thereby affecting the integrity of the signal.

[0003] Therefore, how to achieve impedance matching between the signal source and the load is a problem that needs to be solved urgently. Summary of the Invention

[0004] The present application provides a resistance adjustment circuit and a resistance adjustment method, which solve the problem of impedance matching between a signal source end and a load end. The present application can adjust the resistance of a pull-up resistor array and a pull-down resistor array at a signal source end according to the impedance of the load end, thereby achieving impedance matching between the signal source end and the load end. The resistance adjustment has high accuracy and strong flexibility.

[0005] In a first aspect, the present application provides a resistance adjustment circuit, which includes: a controller; a resistor array selection module, the resistor array selection module is respectively connected to the controller, the pull-up resistor array and the pull-down resistor array, and is used to select the pull-up resistor array or the pull-down resistor array for resistance adjustment under the action of the selection signal output by the controller; a reference voltage adjustment module, the reference voltage adjustment module is respectively connected to the pull-up resistor array and the pull-down resistor array, and is used to output a corresponding reference voltage according to the impedance requirement of the load end; a reference voltage comparison module, the reference voltage comparison module is respectively connected to the reference voltage adjustment module , the pull-down resistor array is connected to the controller and is used to compare the first reference voltage output by the reference voltage adjustment module with the voltage on the pull-down resistor array, so that the controller adjusts the resistance value of the pull-down resistor array according to the voltage comparison result; an adjustment voltage determination module, the adjustment voltage determination module is respectively connected to the reference voltage adjustment module, the first connection end of the pull-up resistor array and the controller, and is used to output a corresponding adjustment voltage according to the comparison result between the second reference voltage output by the reference voltage adjustment module and the voltage on the pull-up resistor array, so that the controller adjusts the resistance value of the pull-up resistor array according to the adjustment voltage.

[0006] Optionally, the resistor array selection module includes: a first transistor, wherein the control end of the first transistor is connected to the gate voltage output end, and the first end of the first transistor is connected to the first power supply end; a first switch, wherein the control end of the first switch is connected to the controller, the first end of the first switch is connected to the second end of the first transistor, and the second end of the first switch is connected to the reference voltage regulation module; a second transistor, wherein the control end of the second transistor is connected to the control end of the first transistor, and the first end of the second transistor is connected to the first end of the first transistor; a second switch, wherein the control end of the second switch is connected to the controller, the first end of the second switch is connected to the second end of the second transistor, and the second end of the second switch is connected to the first connection end of the pull-up resistor array; a third transistor, wherein the control end of the third transistor is connected to the control end of the second transistor, the first end of the third transistor is connected to the first end of the second transistor; and a third switch, wherein the control end of the third switch is connected to the controller, the first end of the third switch is connected to the second end of the third transistor, and the second end of the third switch is connected to the first connection end of the pull-down resistor array.

[0007] Optionally, the resistor array selection module further includes: an operational amplifier, wherein the inverting input terminal of the operational amplifier is connected to the first reference voltage terminal, and the output terminal of the operational amplifier serves as the gate voltage output terminal; a fourth switch, wherein the control terminal of the fourth switch is connected to the controller, the first terminal of the fourth switch is connected to the non-inverting input terminal of the operational amplifier, and the second terminal of the fourth switch is connected to the second terminal of the first switch; and a fifth switch, wherein the control terminal of the fifth switch is connected to the controller, the first terminal of the fifth switch is connected to the first terminal of the fourth switch, and the second terminal of the fifth switch is connected to the first terminal of the second switch.

[0008] Optionally, the reference voltage regulation module includes: a first resistor, wherein the first end of the first resistor is connected to the second end of the first switch, and the second end of the second resistor is grounded; a second resistor, wherein the first end of the second resistor is respectively connected to the second end of the second switch and the control end of the third switch; and a third resistor, wherein the first end of the third resistor is connected to the second end of the second resistor, and the second end of the third resistor is grounded.

[0009] Optionally, the reference voltage comparison module includes: a sixth switch, wherein the control end of the sixth switch is connected to the controller, and the first end of the sixth switch is connected to the second end of the first switch; a seventh switch, wherein the control end of the seventh switch is connected to the controller, the first end of the seventh switch is connected to the second end of the third switch, and the second end of the seventh switch is connected to the second end of the sixth switch; a first capacitor, wherein the first end of the first capacitor is connected to the second end of the sixth switch; and a comparator, wherein the inverting input end of the comparator is grounded, the non-inverting input end of the comparator is connected to the second end of the first capacitor, and the output end of the comparator is connected to the controller.

[0010] Optionally, the reference voltage comparison module also includes: an eighth switch, wherein the control end of the eighth switch is connected to the controller, the first end of the eighth switch is connected to the second reference voltage end, and the second end of the eighth switch is connected to the inverting input end of the comparator; and a ninth switch, wherein the control end of the ninth switch is connected to the controller, the first end of the ninth switch is connected to the non-inverting input end of the comparator, and the second end of the ninth switch is connected to the output end of the comparator.

[0011] Optionally, the reference voltage comparison module also includes: a fourth resistor, a first end of the fourth resistor is connected to the second end of the sixth switch, and the second end of the fourth resistor is connected to the first end of the first capacitor; a second capacitor, a first end of the second capacitor is connected to the second end of the fourth resistor, and the second end of the second capacitor is grounded; a fifth resistor, a first end of the fifth resistor is connected to the second end of the first capacitor, and the second end of the fifth resistor is connected to the non-inverting input terminal of the comparator; a sixth resistor, a first end of the sixth resistor is connected to the inverting input terminal of the comparator; and a third capacitor, a first end of the third capacitor is connected to the second end of the sixth resistor, and the second end of the third capacitor is grounded.

[0012] Optionally, the regulation voltage determination module includes: a differential amplifier, a non-inverting input terminal of the differential amplifier is connected to the second terminal of the second resistor, and an inverting input terminal of the differential amplifier is connected to the first connection terminal of the pull-down resistor array; a fourth transistor, a control terminal of the fourth transistor is connected to the output terminal of the differential amplifier, and a second terminal of the fourth transistor is grounded; a fifth transistor, a control terminal of the fifth transistor is connected to the first terminal of the fourth transistor, a first terminal of the fifth transistor is connected to the first power supply terminal, and a second terminal of the fifth transistor is connected to the control terminal of the fifth transistor; a sixth transistor, a control terminal of the sixth transistor is connected to the control terminal of the fifth transistor, and a first terminal of the sixth transistor is connected to the first terminal of the fifth transistor; a seventh resistor, a first terminal of the seventh resistor is connected to the second terminal of the sixth transistor, a second terminal of the seventh resistor is also connected to the controller, and a second terminal of the seventh resistor is connected to the second power supply terminal.

[0013] Optionally, the pull-up resistor array includes a plurality of pull-up resistor modules connected in parallel, each pull-up resistor module includes a pull-up transistor and a pull-up resistor, the control end of the pull-up transistor is connected to the controller, the first end of the pull-up transistor serves as the first connection end of the pull-up resistor array, the second end of the pull-up transistor is connected to the first end of the pull-up resistor, and the second end of the pull-up resistor serves as the second connection end of the pull-up resistor array; the pull-down resistor array includes a plurality of pull-down resistor modules connected in parallel, each pull-down resistor module includes a pull-down resistor and a pull-down transistor, the first end of the pull-down resistor serves as the first connection end of the pull-down resistor array, the second end of the pull-down resistor is connected to the first end of the pull-down transistor, the control end of the pull-down transistor is connected to the controller, and the second end of the pull-down transistor is grounded.

[0014] In a second aspect, the present application provides a resistance adjustment method, which is applied to a resistance adjustment circuit, and the resistance adjustment method includes: a resistor array selection module connects the pull-down resistor array to the adjustment loop according to a first selection signal output by a controller; a reference voltage comparison module compares the first reference voltage output by the reference voltage adjustment module with the voltage on the pull-down resistor array, and outputs a voltage comparison result; the controller adjusts the resistance value of the pull-down resistor array according to the voltage comparison result; when the resistance value adjustment of the pull-down resistor array is completed, the resistor array selection module outputs a second selection signal according to the controller, and connects the pull-up resistor array to the adjustment loop; an adjustment voltage determination module outputs a corresponding adjustment voltage according to the comparison result of the second reference voltage output by the reference voltage adjustment module and the voltage on the pull-up resistor array; and the controller adjusts the resistance value of the pull-up resistor array according to the adjustment voltage.

[0015] The technical solution provided by this application has at least the following beneficial effects:

[0016] The resistor array selection module of the present application is controlled by a selection signal output by a controller, and selects a corresponding pull-up resistor array or a pull-down resistor array to be connected to the regulation loop, thereby realizing time-sharing resistance regulation of the pull-up resistor array and the pull-down resistor array, and improving the stability and accuracy of the resistance regulation. Furthermore, the reference voltage regulation module of the present application outputs a corresponding first reference voltage and a second reference voltage according to different impedance requirements of the load end; the reference voltage comparison module compares the first reference voltage with the voltage on the pull-down resistor array, so that the controller adjusts the resistance value of the pull-down resistor array according to the voltage comparison result; in addition, the regulation voltage determination module outputs a corresponding regulation voltage according to the second reference voltage, so that the controller adjusts the resistance value of the pull-up resistor array according to the regulation voltage; therefore, the present application can adjust the resistance of the pull-up resistor array and the pull-down resistor array at the signal source end according to the impedance of the load end, thereby realizing impedance matching between the signal source end and the load end, and achieving high resistance regulation accuracy and strong flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0018] Figure 1 Shown is a structural schematic diagram of a resistance adjustment circuit provided in an embodiment of the present application.

[0019] Figure 2 Shown is a schematic structural diagram of a pull-up resistor array and a pull-down resistor array provided in an embodiment of the present application.

[0020] Figure 3 Shown is a circuit diagram of a resistance adjustment circuit provided in an embodiment of the present application.

[0021] Figure 4 The figure is a flow chart of a resistance adjustment method provided in an embodiment of the present application.

[0022] Description of reference numerals:

[0023] 100, resistance adjustment circuit; 110, controller; 120, resistor array selection module; 130, reference voltage adjustment module; 140, reference voltage comparison module; 150, adjustment voltage determination module;

[0024] 200, pull-up resistor array; 210, pull-up resistor module; 300, pull-down resistor array; 310, pull-down resistor module;

[0025] M1, first transistor; M2, second transistor; M3, third transistor; M4, fourth transistor; M5, fifth transistor; M6, sixth transistor; Q1, pull-up transistor; Q2, pull-down transistor;

[0026] T1, first switch; T2, second switch; T3, third switch; T4, fourth switch; T5, fifth switch; T6, sixth switch; T7, seventh switch; T8, eighth switch; T9, ninth switch;

[0027] R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; Ra, pull-up resistor; Rb, pull-down resistor; C1, first capacitor; C2, second capacitor; C3, third capacitor; U1, operational amplifier; U2, comparator; U3, differential amplifier. DETAILED DESCRIPTION

[0028] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art.

[0029] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner.In the following description, many specific details are provided so as to provide a full understanding of the embodiments of the present application. However, it will be appreciated by those skilled in the art that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps etc. can be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0030] The present application is further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be understood as limiting the present application.

[0031] Consider a high-speed digital signal source and a load, transmitted through a transmission line (such as a coaxial cable). The characteristic impedance of the transmission line is 50Ω, a crucial parameter in transmission line design. Here, we explain impedance matching and mismatching in detail:

[0032] 1. Impedance matching: Assume that the output impedance of the signal source is 50Ω and the input impedance of the load is also 50Ω. In this case, the impedances of the signal source, transmission line, and load are completely matched.

[0033] Signal transmission process: The signal source sends a square wave signal, which propagates along the transmission line. The characteristic impedance of the transmission line is 50Ω. When the signal reaches the load end, the impedance of the load end is also 50Ω, and the signal is completely absorbed. Due to impedance matching, the signal is not reflected during the transmission process, and the waveform remains intact. The signal seen by the receiving end is almost the same as the signal waveform sent by the transmitting end.

[0034] 2. Impedance mismatch: Assume that the output impedance of the signal source is still 50Ω, but the input impedance of the load becomes 100Ω. In this case, the impedance of the load does not match the characteristic impedance of the transmission line.

[0035] Signal transmission process: The signal source sends a square wave signal, which propagates along the transmission line. The characteristic impedance of the transmission line is 50Ω. When the signal reaches the load end, due to the mismatch between the impedance of the load end (100Ω) and the characteristic impedance of the transmission line (50Ω), part of the signal will be reflected back to the signal source. The reflected signal is superimposed on the original signal on the transmission line, resulting in a distorted signal waveform seen by the receiving end.

[0036] In order to solve the impedance matching problem between the signal source and the load, the present application provides a resistance adjustment circuit for adjusting the pull-up resistor array and the pull-down resistor array at the signal source so that the impedance between the signal source and the load is matched. The present application specifically includes the following embodiments:

[0037] In a first aspect, the present application provides a resistance adjustment circuit, specifically including the following embodiments:

[0038] Figure 1 FIG. 1 is a schematic diagram showing the structure of a resistance adjustment circuit provided in an embodiment of the present application; Figure 1 As shown, the resistance adjustment circuit 100 includes a controller 110 , which may be a single chip microcomputer or a chip including a plurality of connection ports and having a control program written therein.

[0039] In this embodiment, the resistance adjustment circuit 100 further includes a resistance array selection module 120, which is connected to the controller 110, the pull-up resistor array 200, and the pull-down resistor array 300, respectively, and is used to select the pull-up resistor array 200 or the pull-down resistor array 300 for resistance adjustment under the action of the selection signal output by the controller 110.

[0040] In one embodiment, if Figure 2As shown, the pull-up resistor array 200 includes a plurality of pull-up resistor modules 210 connected in parallel, each pull-up resistor module 210 includes a pull-up transistor Q1 and a pull-up resistor Ra, the control end of the pull-up transistor Q1 is connected to the controller 110, the first end of the pull-up transistor Q1 serves as the first connection end of the pull-up resistor array 200, the second end of the pull-up transistor Q1 is connected to the first end of the pull-up resistor Ra, and the second end of the pull-up resistor Ra serves as the second connection end of the pull-up resistor array 200.

[0041] In this embodiment, the pull-down resistor array 300 includes a plurality of pull-down resistor Rb modules 310 connected in parallel. Each pull-down resistor Rb module 310 includes a pull-down resistor Rb and a pull-down transistor Q2. The first end of the pull-down resistor Rb serves as the first connection end of the pull-down resistor array 300. The second end of the pull-down resistor Rb is connected to the first end of the pull-down transistor Q2. The control end of the pull-down transistor Q2 is connected to the controller 110. The second end of the pull-down transistor Q2 is grounded.

[0042] It should be noted that by controlling the on / off switching of each pull-up transistor Q1 by the controller 110, different numbers and combinations of pull-up resistors Ra can be connected in parallel, thereby adjusting the resistance of the pull-up resistor array 200. Furthermore, due to different gate voltages, the pull-up transistors Q1 output different internal resistances, further fine-tuning the resistance of the pull-up resistor array 200. Similarly, the control principle of the pull-down resistor array 300 is the same as that of the pull-up resistor array 200. When adjusting the resistance of the pull-up resistor array 200 and the pull-down resistor array 300, the first connection terminal of the pull-up resistor array 200 must be connected to the power supply terminal, the second connection terminal of the pull-up resistor array 200 must be connected to the first connection terminal of the pull-down resistor array 300, and the second connection terminal of the pull-down resistor array 300 must be grounded. It is worth noting that, to ensure stability and accuracy of resistance adjustment, the pull-up transistors Q1 and Q2 in this embodiment are of the same model, and the pull-down resistors Rb and Ra have the same resistance value.

[0043] In addition, the resistor array selection module 120 of the present application is controlled by the selection signal output by the controller 110, and selects the corresponding pull-up resistor array 200 or pull-down resistor array 300 to be connected to the adjustment loop, thereby realizing time-sharing resistance adjustment of the pull-up resistor array 200 and the resistance adjustment of the pull-down resistor array 300; for example, when the controller 110 outputs a first selection signal, the resistor array selection module 120 connects the pull-down resistor array 300 to the adjustment loop and disconnects the pull-up resistor array 200, thereby realizing resistance adjustment of the pull-down resistor array 300; when the controller 110 outputs a second selection signal, the resistor array selection module 120 connects the pull-up resistor array 200 to the adjustment loop and disconnects the pull-down resistor array 300, thereby realizing resistance adjustment of the pull-up resistor array 200.

[0044] In this embodiment, the resistance adjustment circuit 100 also includes a reference voltage adjustment module 130, which is connected to the pull-up resistor array 200 and the pull-down resistor array 300, respectively, and is used to output a corresponding reference voltage based on the impedance requirements of the load end. Specifically, based on the impedance requirements of different load ends, reference resistors of different resistance values ​​can be adjusted to be connected to the adjustment loop, thereby providing different reference voltages for the pull-up resistor array 200 and the pull-down resistor array 300.

[0045] In this embodiment, the resistance adjustment circuit 100 further includes a reference voltage comparison module 140, which is connected to the reference voltage adjustment module 130, the pull-down resistor array 300, and the controller 110, respectively. The reference voltage comparison module 140 compares the first reference voltage output by the reference voltage adjustment module 130 with the voltage across the pull-down resistor array 300, causing the controller 110 to adjust the resistance of the pull-down resistor array 300 based on the voltage comparison result. Specifically, the first reference voltage is determined based on the load impedance requirement. Specifically, based on the load impedance requirement, the pull-down resistor array 300 is adjusted to a resistance of 1.2K, corresponding to a first reference voltage of 5V. Therefore, the reference voltage comparison module 140 compares the first reference voltage with the real-time voltage across the pull-down resistor array 300, causing the controller 110 to adjust the resistance of the pull-down resistor array 300 based on the voltage comparison result until the first reference voltage and the real-time voltage across the pull-down resistor array 300 are equal.

[0046] In this embodiment, the resistance adjustment circuit 100 further includes an adjustment voltage determination module 150, which is connected to the reference voltage adjustment module 130, the first connection terminal of the pull-up resistor array 200, and the controller 110, respectively. The adjustment voltage determination module 150 is configured to output an adjustment voltage corresponding to a comparison result between a second reference voltage output by the reference voltage adjustment module 130 and the voltage across the pull-up resistor array 200, causing the controller 110 to adjust the resistance of the pull-up resistor array 200 based on the adjustment voltage. Specifically, the second reference voltage is determined based on the impedance requirements of the load end. That is, when the resistance of the pull-up resistor array 200 is adjusted to 400Ω based on the load end impedance requirements, the corresponding second reference voltage is 3V. Therefore, the adjustment voltage determination module 150 outputs an adjustment voltage corresponding to the second reference voltage to the controller 110, causing the controller 110 to adjust the resistance of the pull-up resistor array 200 based on the adjustment voltage feedback.

[0047] In summary, the resistor array selection module 120 of the present application is controlled by the selection signal output by the controller 110, and selects the corresponding pull-up resistor array 200 or pull-down resistor array 300 to be connected to the adjustment loop, thereby realizing time-sharing resistance adjustment of the pull-up resistor array 200 and the pull-down resistor array 300, and improving the stability and accuracy of the resistance adjustment. Furthermore, the reference voltage adjustment module 130 of the present application outputs a corresponding first reference voltage and a second reference voltage according to different impedance requirements of the load end; the reference voltage comparison module 140 compares the first reference voltage and the voltage on the pull-down resistor array 300, so that the controller 110 adjusts the resistance value of the pull-down resistor array 300 according to the voltage comparison result; in addition, the adjustment voltage determination module 150 outputs a corresponding adjustment voltage according to the second reference voltage, so that the controller 110 adjusts the resistance value of the pull-up resistor array 200 according to the adjustment voltage; therefore, the present application can adjust the resistance of the pull-up resistor array 200 and the pull-down resistor array 300 at the signal source end through the impedance of the load end, thereby achieving impedance matching between the signal source end and the load end, and the resistance adjustment is highly accurate and flexible.

[0048] Figure 3 FIG. 1 is a circuit diagram of a resistance adjustment circuit provided in an embodiment of the present application; FIG. Figure 3 As shown, the resistor array selection module 120 includes: a first transistor M1, a first switch T1, a second transistor M2, a second switch T2, a third transistor M3 and a third switch T3; the control end of the first transistor M1 is connected to the gate voltage output end, and the first end of the first transistor M1 is connected to the first power supply end; the control end of the first switch T1 is connected to the controller 110, the first end of the first switch T1 is connected to the second end of the first transistor M1, and the second end of the first switch T1 is connected to the reference voltage adjustment module 130; the control end of the second transistor M2 is connected to the control end of the first transistor M1, and the first end of the second transistor M2 is connected to the third switch T3; A first end of a transistor M1 is connected; a control end of a second switch T2 is connected to a controller 110, a first end of the second switch T2 is connected to a second end of the second transistor M2, and a second end of the second switch T2 is connected to a first connection end of the pull-up resistor array 200; a control end of a third transistor M3 is connected to a control end of the second transistor M2, a first end of the third transistor M3 is connected to a first end of the second transistor M2; a control end of the third switch T3 is connected to the controller 110, a first end of the third switch T3 is connected to a second end of the third transistor M3, and a second end of the third switch T3 is connected to a first connection end of the pull-down resistor array 300.

[0049] In this embodiment, the control terminals of the first switch T1, the second switch T2, and the third switch T3 are respectively connected to the controller 110 ( Figure 3(not shown), that is, the opening and closing of the first switch T1, the second switch T2, and the third switch T3 are controlled by the controller 110; specifically, when the controller 110 controls the first switch T1 and the third switch T3 to be simultaneously closed and controls the second switch T2 to be disconnected, the pull-down resistor array 300 is selected; when the controller 110 controls the first switch T1 and the third switch T3 to be simultaneously disconnected and controls the second switch T2 to be closed, the pull-up resistor array 200 is selected.

[0050] It should be noted that the gate voltage output terminal is used to output the gate voltage for turning on the first transistor M1, the second transistor M2 and the third transistor M3; in addition, the output current of the first transistor M1 is N times that of the second transistor M2, and the value of N can be determined together with the voltage division ratio of the reference resistor in the reference voltage adjustment module 130; here, this embodiment takes the output current of the first transistor M1 as 6 times that of the second transistor M2 and the third transistor M3 as an example.

[0051] like Figure 3 As shown, in another embodiment, the resistor array selection module 120 further includes an operational amplifier U1, a fourth switch T4, and a fifth switch T5; the inverting input terminal of the operational amplifier U1 is connected to the first reference voltage terminal, and the output terminal of the operational amplifier U1 serves as a gate voltage output terminal; the control terminal of the fourth switch T4 is connected to the controller 110, the first terminal of the fourth switch T4 is connected to the non-inverting input terminal of the operational amplifier U1, and the second terminal of the fourth switch T4 is connected to the second terminal of the first switch T1; the control terminal of the fifth switch T5 is connected to the controller 110, the first terminal of the fifth switch T5 is connected to the first terminal of the fourth switch T4, and the second terminal of the fifth switch T5 is connected to the first terminal of the second switch T2.

[0052] It should be noted that the opening and closing of the fourth switch T4 and the fifth switch T5 are also controlled by the controller 110. When the controller 110 controls the first switch T1 to be closed, it also controls the fourth switch T4 to be closed, so that the operational amplifier U1 performs operational amplification on the first reference voltage outputted from the first reference voltage terminal and uses the amplified voltage as the gate voltage for turning on the first transistor M1.

[0053] like Figure 3 As shown, the reference voltage regulation module 130 includes a first resistor R1, a second resistor R2 and a third resistor R3; the first end of the first resistor R1 is connected to the second end of the first switch T1, and the second end of the second resistor R2 is grounded; the first end of the second resistor R2 is respectively connected to the second end of the second switch T2 and the control end of the third switch T3; the first end of the third resistor R3 is connected to the second end of the second resistor R2, and the second end of the third resistor R3 is grounded.

[0054] It should be noted that the first resistor R1 can be a variable resistor or an external resistor, that is, the resistance value of the first resistor R1 can be made variable by replacing the external resistor. Combining the reference voltage adjustment module 130 with the resistor array selection module 120 shows that: when the first switch T1 and the third switch T3 are closed, that is, when the pull-down resistor array 300 is selected for resistance adjustment, the first reference voltage output by the reference voltage adjustment module 130 is the voltage across the first resistor R1, that is, the voltage at node C; when the second switch T2 is closed, that is, when the pull-up resistor array 200 is selected for resistance adjustment, the second reference voltage output by the reference voltage adjustment module 130 is the voltage across the third resistor R3, that is, the voltage at node B; in addition, Figure 3 In FIG, the voltage on node A is the voltage on the pull-down resistor array 300 .

[0055] like Figure 3 As shown, the reference voltage comparison module 140 includes a sixth switch T6, a seventh switch T7, a first capacitor C1 and a comparator U2. The control end of the sixth switch T6 is connected to the controller 110, and the first end of the sixth switch T6 is connected to the second end of the first switch T1; the control end of the seventh switch T7 is connected to the controller 110, the first end of the seventh switch T7 is connected to the second end of the third switch T3, and the second end of the seventh switch T7 is connected to the second end of the sixth switch T6; the first end of the first capacitor C1 is connected to the second end of the sixth switch T6; the inverting input end of the comparator U2 is grounded, the non-inverting input end of the comparator U2 is connected to the second end of the first capacitor C1, and the output end of the comparator U2 is connected to the controller 110.

[0056] It should be noted that the reference voltage comparison module 140 mainly compares the first reference voltage with the voltage on the pull-down resistor array 300; therefore, while the controller 110 controls the first switch T1 and the third switch T3 to be closed, the controller 110 first controls the sixth switch T6 to be closed and the seventh switch T7 to be opened, so that the first reference voltage on the node C is stored in the first capacitor C1 through the sixth switch T6. Then, the controller 110 controls the sixth switch T6 to be opened and the seventh switch T7 to be closed, so that the voltage on the node A (i.e., the voltage on the pull-down resistor array 300) is stored in the first capacitor C1 through the seventh switch T6. T7 is written into the first capacitor C1; this time, a voltage difference is generated at the first end of the first capacitor C1, and the same voltage difference is also generated at the second end of the capacitor, i.e., the non-inverting input end of the comparator U2. The comparator U2 compares the voltage difference with the low level (assuming it is 0V) at the ground end. If the voltage difference is greater than 0V, the comparator U2 outputs a high level, causing the controller 110 to continue adjusting the resistance value of the pull-down resistor array 300. If the voltage difference is equal to or less than 0V, the comparator U2 outputs a low level. The comparator U2 flips from a high level to a low level, indicating that the resistance value of the pull-down resistor array 300 has been adjusted.

[0057] Optionally, the reference voltage comparison module 140 further includes: an eighth switch T8 and a ninth switch T9, wherein the control end of the eighth switch T8 is connected to the controller 110, the first end of the eighth switch T8 is connected to the second reference voltage end, and the second end of the eighth switch T8 is connected to the inverting input end of the comparator U2; the control end of the ninth switch T9 is connected to the controller 110, the first end of the ninth switch T9 is connected to the non-inverting input end of the comparator U2, and the second end of the ninth switch T9 is connected to the output end of the comparator U2. Specifically, when the controller 110 controls the sixth switch T6 to be closed, the eighth switch T8 and the ninth switch T9 are controlled to be closed simultaneously, and the input and output ends of the comparator U2 are reset by the reference voltage output from the second reference voltage end, thereby improving the accuracy of the voltage comparison.

[0058] Optionally, the reference voltage comparison module 140 also includes a fourth resistor R4, a second capacitor C2, a fifth resistor R5, a sixth resistor R6 and a third capacitor C3, the first end of the fourth resistor R4 is connected to the second end of the sixth switch T6, and the second end of the fourth resistor R4 is connected to the first end of the first capacitor C1; the first end of the second capacitor C2 is connected to the second end of the fourth resistor R4, and the second end of the second capacitor C2 is grounded; the first end of the fifth resistor R5 is connected to the second end of the first capacitor C1, and the second end of the fifth resistor R5 is connected to the non-inverting input end of the comparator U2; the first end of the sixth resistor R6 is connected to the inverting input end of the comparator U2; the first end of the third capacitor C3 is connected to the second end of the sixth resistor R6, and the second end of the third capacitor C3 is grounded.

[0059] It should be noted that the second capacitor C2, the third capacitor C3 and the sixth resistor R6 of this embodiment each have a filtering function.

[0060] like Figure 3As shown, the regulated voltage determination module 150 includes a differential amplifier U3, a fourth transistor M4, a fifth transistor M5, a sixth transistor M6, and a seventh resistor R7; a non-inverting input terminal of the differential amplifier U3 is connected to the second terminal of the second resistor R2, and an inverting input terminal of the differential amplifier U3 is connected to the first connection terminal of the pull-down resistor array 300; a control terminal of the fourth transistor M4 is connected to the output terminal of the differential amplifier U3, and a second terminal of the fourth transistor M4 is grounded; a control terminal of the fifth transistor M5 is connected to the first terminal of the fourth transistor M4, a first terminal of the fifth transistor M5 is connected to the first power supply terminal, and a second terminal of the fifth transistor M5 is connected to the control terminal of the fifth transistor M5; a control terminal of the sixth transistor M6 is connected to the control terminal of the fifth transistor M5, and a first terminal of the sixth transistor M6 is connected to the first terminal of the fifth transistor M5; a first terminal of the seventh resistor R7 is connected to the second terminal of the sixth transistor M6, a second terminal of the seventh resistor R7 is further connected to the controller 110, and a second terminal of the seventh resistor R7 is connected to the second power supply terminal.

[0061] It should be noted that the function of the adjustment voltage determination module 150 is to determine the gate voltage of the pull-up transistor Q1 in the pull-up resistor array 200 controlled by the controller 110, that is, to output the corresponding node voltage based on the comparison result of the voltage at node B and the voltage at node A. Specifically, when the pull-up resistor array 200 is adjusted, the second switch T2 is closed. At this time, the current in the second switch T2 is divided into two paths: one path flows through the pull-up resistor array 200 and the pull-down resistor array 300, and the other path flows through the second resistor R2 and the third resistor R3. In this embodiment, the second reference voltage at node B and the voltage at node A are input into the differential amplifier U3 for comparison. The differential amplifier U3 outputs different voltages based on the voltage difference between the two input voltages. The corresponding adjustment voltage is obtained through the current source composed of the fourth transistor M4, the fifth transistor M5, and the sixth transistor M6. That is, the upper voltage of node D is VP+I2×R7, and the current I2 varies according to the voltage output by the differential amplifier U3. When VA = VB, the pull-up resistor array 200 is adjusted.

[0062] In a second aspect, the present application provides a resistance adjustment method, which specifically includes the following embodiments:

[0063] Figure 4 FIG. 1 is a flow chart of a resistance adjustment method provided in an embodiment of the present application; FIG. Figure 4 As shown, the adjustment method specifically includes the following steps:

[0064] Step S100: The resistor array selection module connects the pull-down resistor array to the regulation loop according to the first selection signal output by the controller.

[0065] Step S200: The reference voltage comparison module compares the first reference voltage output by the reference voltage adjustment module with the voltage on the pull-down resistor array, and outputs a voltage comparison result.

[0066] Step S300: The controller adjusts the resistance value of the pull-down resistor array according to the voltage comparison result.

[0067] Step S400: When the resistance value of the pull-down resistor array is adjusted, the resistor array selection module outputs a second selection signal according to the controller, and connects the pull-up resistor array to the adjustment loop.

[0068] Step S500: The regulated voltage determining module outputs a corresponding regulated voltage according to a comparison result between the second reference voltage output by the reference voltage regulating module and the voltage on the pull-up resistor array.

[0069] Step S600: The controller adjusts the resistance value of the pull-up resistor array according to the adjustment voltage.

[0070] It should be noted that the resistance adjustment method provided in this embodiment is mainly applied to the resistance adjustment circuit in the above embodiment; the resistance adjustment method is divided into pull-down resistor array adjustment and pull-up resistor array adjustment. Figure 3 The specific process of the resistance adjustment method is described in detail:

[0071] 1. Pull-down resistor array adjustment process: The controller outputs a first selection signal, controlling the first switch T1, the third switch T3, and the fourth switch T4 to close. The current output from the first transistor M1 flows through the first switch T1 to the first resistor R1, and the current output from the third transistor M3 flows through the third switch T3 and node A to the pull-down resistor array. At the same time, the controller first controls the sixth switch T6 to close and the seventh switch T7 to open, so that the voltage VC at the node C (i.e., the voltage across the first resistor R1) is written into the first capacitor C1 through the sixth switch T6. Then, the controller controls the sixth switch T6 to open and the seventh switch T7 to close, so that the voltage VA at the node A is written into the first capacitor C1 through the seventh switch T7. This time, a voltage difference is generated at the first end of the first capacitor C1. At the same time, the second end of the capacitor, the non-inverting input of the comparator U2, will also produce the same voltage difference , the comparator U2 compares the voltage difference with the low level on the ground terminal (assuming it is 0V). If the voltage difference is greater than 0V, the comparator U2 outputs a high level, causing the controller to continue adjusting the resistance value of the pull-down resistor array; if the voltage difference is equal to or less than 0V, the comparator U2 outputs a low level. The comparator U2 flips from a high level to a low level, indicating that the resistance value of the pull-down resistor array 300 has been adjusted. Among them, the adjustment result of the pull-down resistor array 300 can be understood as a binary sequence. For example: Figure 2In the pull-down resistor array, when the adjustment result is 1000, it means that from left to right, the first pull-down transistor Q2 is closed, the second pull-down transistor Q2 is disconnected, the third pull-down transistor Q2 is disconnected, and the fourth pull-down transistor Q2 is disconnected; if the adjustment result is 0110, it means that the first pull-down transistor Q2 is disconnected, the second pull-down transistor Q2 is closed, the third pull-down transistor Q2 is closed, and the fourth pull-down transistor Q2 is disconnected. The adjustment results corresponding to other binary sequences follow the same control principle and are not described in detail here.

[0072] 2. Pull-up resistor array adjustment process: The controller outputs a second selection signal to control the second switch T2 and the fifth switch T5 to be closed, and the other switches to be open; the current output from the second transistor M2 is divided into two paths after passing through the second switch T2, one path flows through the pull-up resistor array and the pull-down resistor array, and the other path flows through the second resistor R2 and the third resistor R3; at this time, the voltage VB on the node B and the voltage VA at the node A are input into the differential amplifier U3 for comparison. The differential amplifier U3 outputs different voltages according to the different voltage differences between the two input voltages, and obtains the corresponding adjustment voltage after passing through the current source composed of the fourth transistor M4, the fifth transistor M5 and the sixth transistor M6, that is, the voltage VD of the node D = VP + I2 × R7. The current of I2 changes according to the voltage change output by the differential amplifier U3; when VA =VB, the pull-up resistor array is adjusted. The adjustment result of the pull-up resistor array is also a binary sequence similar to the adjustment result of the pull-down resistor array. In addition, in order to improve the adjustment efficiency of the pull-up resistor array, the controller can first assign the adjustment result of the pull-down resistor to the pull-up resistor array, and then perform fine-tuning based on this.

[0073] It is worth noting that the resistance values ​​of the pull-up resistor array and the pull-down resistor array can be adjusted to be equal or different. In addition, the resistance ratio of the pull-up resistor array and the pull-down resistor array is adjusted accordingly by the ratio of the second resistor to the third resistor. By changing the resistance value of the first resistor, the required resistance value of the pull-down resistor array during the current adjustment process can be determined: 6×I1×R1=I1×pull-down resistor array.

[0074] In this application, it is applicable to the mipi dphy protocol with a Vcomm voltage of 400mv (low differential swing). The pull-up resistor array uses an N-type MOS tube in series with the resistor to ensure that the switch is turned on while reducing power consumption.

[0075] Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first," "second," or "third" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0076] In the description of this specification, the reference terms "some embodiments", "exemplarily", etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0077] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application. Therefore, any changes or modifications made in accordance with the claims and description of the present application should fall within the scope of the patent application.

Claims

1. A resistance adjustment circuit, characterized in that: The resistance adjustment circuit includes: Controller; a resistor array selection module, the resistor array selection module being connected to the controller, the pull-up resistor array, and the pull-down resistor array, respectively, and configured to select the pull-up resistor array or the pull-down resistor array for resistance adjustment under the action of a selection signal output by the controller; a reference voltage regulating module, the reference voltage regulating module being connected to the pull-up resistor array and the pull-down resistor array, respectively, and being configured to output a corresponding reference voltage according to an impedance requirement of a load end; a reference voltage comparison module, the reference voltage comparison module being connected to the reference voltage adjustment module, the pull-down resistor array, and the controller, and being configured to compare a first reference voltage output by the reference voltage adjustment module with the voltage on the pull-down resistor array, so that the controller adjusts the resistance value of the pull-down resistor array according to a voltage comparison result; an adjustment voltage determination module, the adjustment voltage determination module being connected to the reference voltage adjustment module, the first connection end of the pull-up resistor array, and the controller, respectively, and configured to output a corresponding adjustment voltage based on a comparison result between a second reference voltage output by the reference voltage adjustment module and the voltage on the pull-up resistor array, so that the controller adjusts the resistance value of the pull-up resistor array based on the adjustment voltage; The resistor array selection module includes a first transistor, a first switch, a second transistor, a second switch, a third transistor, and a third switch; the control end of the first transistor is connected to the gate voltage output end, and the first end of the first transistor is connected to the first power supply end; the control end of the first switch is connected to the controller, the first end of the first switch is connected to the second end of the first transistor, and the second end of the first switch is connected to the reference voltage regulation module; the control end of the second transistor is connected to the control end of the first transistor, and the first end of the second transistor is connected to the first end of the first transistor; the control end of the second switch is connected to the controller, the first end of the second switch is connected to the second end of the second transistor, and the second end of the second switch is connected to the first connection end of the pull-up resistor array; the control end of the third transistor is connected to the control end of the second transistor, the first end of the third transistor is connected to the first end of the second transistor; the control end of the third switch is connected to the controller, the first end of the third switch is connected to the second end of the third transistor, and the second end of the third switch is connected to the first connection end of the pull-down resistor array.

2. The resistance adjustment circuit according to claim 1, wherein: The resistor array selection module further includes: an operational amplifier, wherein an inverting input terminal of the operational amplifier is connected to the first reference voltage terminal, and an output terminal of the operational amplifier serves as the gate voltage output terminal; a fourth switch, wherein a control end of the fourth switch is connected to the controller, a first end of the fourth switch is connected to the non-inverting input end of the operational amplifier, and a second end of the fourth switch is connected to the second end of the first switch; A fifth switch, wherein a control end of the fifth switch is connected to the controller, a first end of the fifth switch is connected to the first end of the fourth switch, and a second end of the fifth switch is connected to the first end of the second switch.

3. The resistance adjustment circuit according to claim 1, wherein: The reference voltage adjustment module includes: a first resistor, wherein a first end of the first resistor is connected to the second end of the first switch, and a second end of the first resistor is grounded; a second resistor, wherein a first end of the second resistor is connected to the second end of the second switch and the control end of the third switch respectively; a third resistor, wherein a first end of the third resistor is connected to the second end of the second resistor, and a second end of the third resistor is grounded.

4. The resistance adjustment circuit according to claim 1, wherein: The reference voltage comparison module includes: a sixth switch, wherein a control end of the sixth switch is connected to the controller, and a first end of the sixth switch is connected to the second end of the first switch; a seventh switch, wherein a control end of the seventh switch is connected to the controller, a first end of the seventh switch is connected to the second end of the third switch, and a second end of the seventh switch is connected to the second end of the sixth switch; a first capacitor, wherein a first end of the first capacitor is connected to a second end of the sixth switch; A comparator, wherein the inverting input terminal of the comparator is grounded, the non-inverting input terminal of the comparator is connected to the second terminal of the first capacitor, and the output terminal of the comparator is connected to the controller.

5. The resistance adjustment circuit according to claim 4, wherein: The reference voltage comparison module also includes: an eighth switch, wherein a control end of the eighth switch is connected to the controller, a first end of the eighth switch is connected to the second reference voltage end, and a second end of the eighth switch is connected to the inverting input end of the comparator; A ninth switch, wherein the control end of the ninth switch is connected to the controller, the first end of the ninth switch is connected to the non-inverting input end of the comparator, and the second end of the ninth switch is connected to the output end of the comparator.

6. The resistance adjustment circuit according to claim 4, wherein: The reference voltage comparison module also includes: a fourth resistor, wherein a first end of the fourth resistor is connected to the second end of the sixth switch, and a second end of the fourth resistor is connected to the first end of the first capacitor; a second capacitor, wherein a first end of the second capacitor is connected to the second end of the fourth resistor, and a second end of the second capacitor is grounded; a fifth resistor, wherein a first end of the fifth resistor is connected to the second end of the first capacitor, and a second end of the fifth resistor is connected to the non-inverting input terminal of the comparator; a sixth resistor, wherein a first end of the sixth resistor is connected to the inverting input end of the comparator; A third capacitor, wherein a first end of the third capacitor is connected to the second end of the sixth resistor, and a second end of the third capacitor is grounded.

7. The resistance adjustment circuit according to claim 3, wherein: The regulated voltage determination module includes: a differential amplifier, wherein a non-inverting input terminal of the differential amplifier is connected to the second end of the second resistor, and an inverting input terminal of the differential amplifier is connected to the first connection terminal of the pull-down resistor array; a fourth transistor, wherein a control terminal of the fourth transistor is connected to the output terminal of the differential amplifier, and a second terminal of the fourth transistor is grounded; a fifth transistor, wherein a control terminal of the fifth transistor is connected to the first terminal of the fourth transistor, the first terminal of the fifth transistor is connected to the first power supply terminal, and the second terminal of the fifth transistor is connected to the control terminal of the fifth transistor; a sixth transistor, wherein a control terminal of the sixth transistor is connected to the control terminal of the fifth transistor, and a first terminal of the sixth transistor is connected to the first terminal of the fifth transistor; A seventh resistor, wherein a first end of the seventh resistor is connected to the second end of the sixth transistor, a second end of the seventh resistor is further connected to the controller, and a second end of the seventh resistor is connected to the second power supply end.

8. The resistance adjustment circuit according to any one of claims 1 to 7, characterized in that: The pull-up resistor array includes a plurality of pull-up resistor modules connected in parallel, each pull-up resistor module includes a pull-up transistor and a pull-up resistor, the control end of the pull-up transistor is connected to the controller, the first end of the pull-up transistor serves as the first connection end of the pull-up resistor array, the second end of the pull-up transistor is connected to the first end of the pull-up resistor, and the second end of the pull-up resistor serves as the second connection end of the pull-up resistor array; The pull-down resistor array includes a plurality of pull-down resistor modules connected in parallel, each pull-down resistor module includes a pull-down resistor and a pull-down transistor, the first end of the pull-down resistor serves as the first connection end of the pull-down resistor array, the second end of the pull-down resistor is connected to the first end of the pull-down transistor, the control end of the pull-down transistor is connected to the controller, and the second end of the pull-down transistor is grounded.

9. A resistance adjustment method, characterized in that: Applied to the resistance adjustment circuit according to any one of claims 1 to 8, the resistance adjustment method comprises: The resistor array selection module connects the pull-down resistor array to the regulation loop according to the first selection signal output by the controller; The reference voltage comparison module compares the first reference voltage output by the reference voltage adjustment module with the voltage on the pull-down resistor array, and outputs a voltage comparison result; The controller adjusts the resistance value of the pull-down resistor array according to the voltage comparison result; When the resistance value of the pull-down resistor array is adjusted, the resistor array selection module outputs a second selection signal according to the controller, and connects the pull-up resistor array to the adjustment loop; The adjustment voltage determination module outputs a corresponding adjustment voltage according to a comparison result between the second reference voltage output by the reference voltage adjustment module and the voltage on the pull-up resistor array; The controller adjusts the resistance value of the pull-up resistor array according to the adjustment voltage.

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