CN114744992A - Circuit driver impedance calibration overvoltage protection circuit and method - Google Patents
Circuit driver impedance calibration overvoltage protection circuit and method Download PDFInfo
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- CN114744992A CN114744992A CN202210178186.4A CN202210178186A CN114744992A CN 114744992 A CN114744992 A CN 114744992A CN 202210178186 A CN202210178186 A CN 202210178186A CN 114744992 A CN114744992 A CN 114744992A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/003—Modifications for increasing the reliability for protection
- H03K19/00315—Modifications for increasing the reliability for protection in field-effect transistor circuits
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/0175—Coupling arrangements; Interface arrangements
- H03K19/017509—Interface arrangements
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Abstract
The invention relates to a line driver impedance calibration overvoltage protection circuit and a method thereof, which are applied to Ethernet and comprise a first impedance calibration circuit and an overvoltage protection circuit, wherein the first impedance calibration circuit comprises: the two ends of each first transmission gate are respectively connected with a first resistor and a second resistor, and the first transmission gates can be controlled to be switched on or switched off so as to adjust the impedance between the line driver and the first connection end to a preset value; the overvoltage protection circuit is used for detecting the amplitude of an opposite end signal received by the hybrid circuit; comparing the amplitude of the opposite terminal signal with a preset threshold value and outputting a comparison signal; and controlling the amplitude of the local end signal sent by the line driver according to the comparison signal. The invention can realize impedance calibration, and the transmission gate works at the intermediate voltage, the voltage interval range is smaller, so as to protect the transmission gate from overvoltage, and the tolerance of the reliability of the Ethernet is better; and limiting the transmitting amplitude of the local terminal to further realize the overvoltage protection of impedance calibration.
Description
Technical Field
The invention relates to the field of impedance calibration and overvoltage protection, in particular to an impedance calibration overvoltage protection circuit and method for a line driver.
Background
The line driver is divided into a voltage-type line driver and a current-type line driver, and is a digital modulation and demodulation technology based on a high-speed digital signal processing technology, which is also a key for determining whether modern communication transmission performance is excellent. However, to transmit the modulated signal to the twisted pair without distortion and to meet the required output power, a high performance analog interface circuit is required to process the signal. The analog interface circuit mainly comprises a line driving circuit, a signal transceiving circuit and a hybrid circuit.
The existing advanced process chips such as 28/14nm process and the like only have 1.8V devices, and the transmission voltage amplitude is regulated to be 2V Vpp by an Ethernet protocol, so that the overpressure design needs 3.3V power supply to work. In the overvoltage design in the prior art, usually a CMOS transistor is added with a protection voltage, but the voltage amplitude of an opposite-end signal is superimposed in a transmission process, the voltage amplitude output to a transmission line is large, and the reliability is low.
Disclosure of Invention
In view of the above problems, the present invention provides an overvoltage protection circuit and method for calibrating impedance of a line driver.
The technical problem solved by the invention can be realized by adopting the following technical scheme:
a line driver impedance calibration overvoltage protection circuit applied to Ethernet comprises:
a first impedance calibration circuit connected between a line driver and a first connection of a hybrid circuit, the first impedance calibration circuit comprising:
the two ends of each first transmission gate are respectively connected with a first resistor and a second resistor, and each first transmission gate can be controllably switched on or off under the action of a switch control signal so as to adjust the impedance between the line driver and the first connecting end to a preset value;
an overvoltage protection circuit connecting the line driver and the hybrid circuit, respectively, the overvoltage protection circuit comprising:
the amplitude detection circuit is used for detecting the amplitude of the opposite terminal signal received by the mixing circuit;
the digital control circuit is used for comparing the amplitude of the opposite end signal with a preset threshold value and outputting a comparison signal;
and the amplitude control circuit is used for controlling the amplitude of the local end signal sent by the line driver according to the comparison signal.
In the above circuit driver impedance calibration overvoltage protection circuit, the circuit driver further includes: a second impedance calibration circuit connected between the line driver and the second connection of the hybrid circuit, the second impedance calibration circuit comprising:
and two ends of each second transmission gate are respectively connected with a third resistor and a fourth resistor, and each second transmission gate can be controllably switched on or switched off under the action of the switch control signal so as to adjust the impedance between the line driver and the second connecting end to the preset value.
In the above line driver impedance calibration overvoltage protection circuit, when the amplitude of the opposite-end signal is greater than the predetermined threshold, the amplitude control circuit controls the amplitude of the transmitted local-end signal to be reduced by half;
and when the amplitude of the opposite-end signal is less than or equal to the preset threshold value, sending the opposite-end signal according to the original amplitude of the local-end signal.
In the above circuit driver impedance calibration overvoltage protection circuit, the circuit driver further includes:
a first voltage dividing circuit for outputting a first intermediate voltage;
the second voltage division circuit is used for outputting a second intermediate voltage;
the input end of the level conversion unit is connected with the first voltage division circuit and the second voltage division circuit respectively, and the output end of the level conversion unit is connected with each first transmission gate respectively and used for switching between the first intermediate voltage and the second intermediate voltage to output the switch control signal so as to control the branch where each first transmission gate is located between the line driver and the first connection end to be switched on or switched off respectively.
In the above circuit driver impedance calibration overvoltage protection circuit, the first transmission gate includes:
the source and drain electrodes are connected in parallel with a first PMOS tube and a first NMOS tube;
the grid electrode of the first PMOS tube is connected with the switch control signal, the drain electrode of the first PMOS tube is connected with the first resistor, and the source electrode of the first PMOS tube is connected with the second resistor;
and the grid electrode of the first NMOS tube is connected with the inverted signal of the switch control signal.
In the above circuit driver impedance calibration overvoltage protection circuit, the circuit driver further includes:
a first voltage dividing circuit for outputting a first intermediate voltage;
the second voltage division circuit is used for outputting a second intermediate voltage;
and an input end of the level conversion unit is connected to the first voltage division circuit and the second voltage division circuit, and an output end of the level conversion unit is connected to each of the second transmission gates, and is configured to switch between the first intermediate voltage and the second intermediate voltage to output the switch control signal, so as to control a branch where each of the second transmission gates is located between the line driver and the second connection end to be turned on or off.
In the above circuit driver impedance calibration overvoltage protection circuit, the second transmission gate includes:
the source and drain electrodes of the second PMOS tube and the second NMOS tube are connected in parallel;
the grid electrode of the second PMOS tube is connected with the switch control signal, the drain electrode of the second PMOS tube is connected with the third resistor, and the source electrode of the second PMOS tube is connected with the fourth resistor;
and the grid electrode of the second NMOS tube is connected with the inverted signal of the switch control signal.
In the above circuit for protecting the line driver from the overvoltage, the line driver is a voltage-type line driver.
The invention also provides a line driver impedance calibration overvoltage protection method, which is characterized by being applied to the line driver impedance calibration overvoltage protection circuit, wherein the method comprises the following steps:
each first transmission gate is controllably switched on or switched off under the action of a switch control signal so as to adjust the impedance between the line driver and the first connection end of the hybrid circuit to a preset value; and/or
Under the action of the switch control signal, each second transmission gate is controllably switched on or switched off so as to adjust the impedance between the line driver and the second connecting end of the hybrid circuit to the preset value;
further comprising: detecting the amplitude of an opposite terminal signal received by the hybrid circuit;
comparing the amplitude of the detected opposite-end signal with a preset threshold value and outputting a comparison signal;
and controlling the amplitude of the local end signal sent by the line driver according to the comparison signal.
In the method for protecting the line driver from overvoltage during impedance calibration, the method further includes:
when the amplitude of the opposite-end signal is larger than the preset threshold value, controlling the amplitude of the transmitted local-end signal to be halved;
and when the amplitude of the opposite-end signal is less than or equal to the preset threshold value, sending the opposite-end signal according to the original amplitude of the local-end signal.
The technical scheme of the invention has the beneficial effects that: impedance between a line driver and a first connecting end and a second connecting end of a hybrid circuit is limited to a preset value through a transmission gate, so that impedance calibration is realized, the transmission gate works at an intermediate voltage, the range of a working voltage interval is smaller, overvoltage is prevented, and the tolerance of the reliability of the Ethernet is better; and limiting the sending amplitude of the local terminal according to the sending amplitude of the opposite terminal by detecting the sending amplitude of the opposite terminal, thereby realizing the overvoltage protection of impedance calibration.
Drawings
FIG. 1 is a block diagram of a line driver impedance calibration overvoltage protection circuit in accordance with the present invention;
FIG. 2 is a circuit schematic of a line driver impedance calibration overvoltage protection circuit in accordance with the present invention;
FIG. 3 is a circuit diagram of a preferred embodiment of the present invention;
FIG. 4 is a circuit schematic of a first transmission gate of the present invention;
FIG. 5 is a circuit diagram of a second transmission gate according to the present invention;
fig. 6 is a schematic flow chart of the overpressure protection in the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive efforts based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.
It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other without conflict.
The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.
The embodiment of the invention can be applied to single-ended and differential, for example, if only a first impedance calibration circuit is arranged between the first connecting end of the line driver 1 and the hybrid circuit, or only a second impedance calibration circuit is arranged between the second connecting end of the line driver 1 and the hybrid circuit 8, the single-ended control is realized; if a first impedance calibration circuit is arranged between the first connection terminals of the line driver 1 and the hybrid circuit 8, and a second impedance calibration circuit is arranged between the second connection terminals of the line driver 1 and the hybrid circuit 8, the differential control is performed.
Example one
Referring to fig. 1-2, an embodiment of the present invention provides an impedance calibration overvoltage protection circuit for a line driver 1, which is applied to an ethernet network, and includes:
a first impedance calibration circuit connected between a line driver 1 and a first connection terminal of a hybrid circuit 8, the first impedance calibration circuit comprising:
a plurality of first Transmission Gates (TG)11…TG1i) Each first Transmission Gate (TG)11…TG1i) Are respectively connected with a first resistor (R)11…R1i) And a second resistor (R)21…R2i) Each first Transmission Gate (TG)11…TG1i) The circuit driver 1 is connected with the first connection end through the first connection end and the second connection end;
an overvoltage protection circuit, respectively connecting the line driver 1 and the hybrid circuit 8, the overvoltage protection circuit comprising:
an amplitude detection circuit for detecting the amplitude of the opposite-end signal received by the hybrid circuit 8;
the digital control circuit is used for comparing the amplitude of the opposite terminal signal with a preset threshold value and outputting a comparison signal;
and the amplitude control circuit is used for controlling the amplitude of the local end signal sent by the line driver 1 according to the comparison signal.
Specifically, the embodiment of the invention includes a line driver 1 for driving a network line with a characteristic impedance of 50 ohms, and a plurality of first resistance branches connected between a first connection end and the line driver 1, where each first resistance branch includes a first Transmission Gate (TG)11…TG1i) A first resistor (R)11…R1i) And a second resistance (R)21…R2i) (ii) a The impedance between the line driver 1 and the first connection end is adjusted to a preset value by detecting the parallel impedance deviation of the first resistor branches communicated between the first connection end and the line driver 1 and controlling the number of the communicated first resistor branches according to the deviation, and preferably, the total resistance value of all the communicated first resistor branches after being connected in parallel is 50 ohms.
The impedance calibration circuit adopts a 1.8V device, the amplitude of a transmission signal is specified to be 2V Vpp by an Ethernet protocol, after the amplitude of an opposite-end signal is superposed, a single end can reach 2V Vpp, and the difference can reach 4V Vpp, so that an overpressure design is required. In order to avoid the influence caused by the overvoltage design, the invention also comprises an overvoltage protection circuit, and the amplitude of the opposite end signal received by the hybrid circuit 8 is detected through the overvoltage protection circuit; and comparing the amplitude of the detected opposite-end signal with a preset threshold value, outputting a comparison signal, and controlling the amplitude of the local-end signal transmitted by the line driver 1 according to the comparison signal so as to limit the transmission amplitude of the local-end signal.
The embodiment of the invention adopts the 1.8V device, which not only can realize impedance calibration, but also has smaller range of working voltage range and better tolerance to the reliability of the vehicle-mounted Ethernet; and limiting the sending amplitude of the local terminal according to the sending amplitude of the opposite terminal by detecting the sending amplitude of the opposite terminal, thereby realizing calibrated overpressure protection.
As a preferred embodiment, the method further comprises the following steps: a second impedance calibration circuit connected between the line driver 1 and the second connection of the hybrid circuit 8, the second impedance calibration circuit comprising:
a plurality of second Transmission Gates (TG)21…TG2i) Each second Transmission Gate (TG)21…TG2i) Are respectively connected with a third resistor (R)31…R3i) And a fourth resistor (R)41…R5i) Each second Transmission Gate (TG)21…TG2i) The impedance between the line driver 1 and the second connection terminal is adjusted to a predetermined value by being controllably turned on or off under the action of the switch control signal.
Specifically, the embodiment of the present invention further includes a plurality of second resistive branches connected between the second connection end and the line driver 1, and each of the second resistive branches includes a second Transmission Gate (TG)21…TG2i) A third resistor (R)31…R3i) And a fourth resistor (R)41…R5i). Likewise, by detecting a deviation of the parallel impedance of the connected second resistor branches between the second connection terminal and the line driver 1, the number of connected second resistor branches is controlled according to the deviation to adjust the impedance between the line driver 1 and the second connection terminal to a preset value, preferably, the total resistance of all connected second resistor branches after being connected in parallel is 50 ohms.
As a preferred embodiment, when the amplitude of the peer-to-peer signal is greater than a predetermined threshold, the amplitude control circuit controls the amplitude of the transmitted home-end signal to be halved;
and when the amplitude of the opposite-end signal is less than or equal to a preset threshold value, sending the opposite-end signal according to the original amplitude of the local-end signal.
Specifically, in the embodiment of the present invention, the amplitude detection circuit detects the opposite-end transmission amplitude (i.e., the amplitude of the opposite-end transmission signal) of the opposite-end hybrid circuit 8 through the analog-to-digital converter 5, and when the opposite-end transmission amplitude is large, that is, the amplitude of the opposite-end transmission signal exceeds a predetermined threshold, the amplitude control circuit performs amplitude limiting on the amplitude of the local-end transmission signal through the digital-to-analog converter 4, so as to reduce the voltage amplitude of the local-end transmission signal. Preferably, the specific value of the predetermined threshold value can be determined according to the actual application.
Further, in order to avoid the over-voltage after the transmission amplitudes of the opposite end and the local end are superimposed, the local end transmission amplitude is controlled to be reduced through the digital-to-analog converter 4, and then the local end transmission amplitude is sent to the opposite end hybrid circuit 8.
Further, a preset amplitude limiting strategy can be set, the digital-to-analog converter 4 controls the sending amplitude of the local terminal according to the preset amplitude limiting strategy, and the preset amplitude limiting strategy specifically includes:
Vt＝Vi*A；
wherein, Vt represents the local terminal sending amplitude controlled by the digital-to-analog converter 4 based on an amplitude control signal;
vi represents the original local sending amplitude;
a denotes a clipping coefficient.
If the opposite end transmission amplitude is a large swing, a is less than 1, and in a preferred embodiment, a is 0.5;
if the opposite end transmission amplitude is a small swing, A is 1.
As a preferred embodiment, as shown in fig. 3, the method further includes:
a first voltage dividing circuit 71 for outputting a first intermediate voltage;
a second voltage dividing circuit 72 for outputting a second intermediate voltage;
a level shift unit 6, the input terminals of which are respectively connected to the first voltage divider circuit 71 and the second voltage divider circuit 72, and the output terminals of which are respectively connected to each of the first Transmission Gates (TG)11…TG1i) For switching between a first intermediate voltage and a second intermediate voltage for outputting a switching control signal for controlling each first Transmission Gate (TG) between the line driver 1 and the first connection terminal11…TG1i) The branch circuits are respectively switched on or off, preferably, in the embodiment of the present invention, the first transmission gate and the second transmission gate are triggered by using an intermediate voltage to protect the PMOS transistor and the NMOS transistor constituting the transmission gates from overvoltage, and a specific value of the intermediate voltage is determined according to an actual circuit design.
Specifically, in this embodiment, a plurality of level shift units 6 may be provided, and the plurality of level shift units 6 are respectively connected to a corresponding transmission gate (including the first transmission gate and the second transmission gate).
The level conversion unit 6 is used for switching between the first intermediate voltage and the second intermediate voltage to output a control signal to control the correspondingly connected transmission gate to switch between an on state and an off state, so as to adjust the resistance values of the resistors on the two sides to be at a preset value.
Further, the first voltage dividing circuit 71 divides the voltage by resistors to output a first intermediate voltage; the second voltage division circuit 72 divides the voltage by a resistor to output a second intermediate voltage, so that the transmission gate works between the first intermediate voltage and the second intermediate voltage, the working voltage interval range between the first intermediate voltage and the second intermediate voltage is smaller, and the tolerance of the transmission gate to reliability is better when the transmission gate is applied to the vehicle-mounted Ethernet.
As a preferred embodiment, among others, as shown in FIG. 4, a first Transfer Gate (TG)11…TG1i) The method comprises the following steps:
a first PMOS tube MP1 and a first NMOS tube MN1, the source and the drain of which are connected in parallel;
the gate of the first PMOS transistor MP1 is connected to the control signal, and the drain of the first PMOS transistor MP1 is connected to the first resistor (R)11…R1i) The source of the first PMOS transistor MP1 is connected with a second resistor (R)21…R2i)；
The gate of the first NMOS transistor MN1 is connected to the inverted signal of the switch control signal.
As a preferred embodiment, among others, as shown in fig. 5, a second Transmission Gate (TG)21…TG2i) The method comprises the following steps:
the source and drain electrodes of the second PMOS tube MP2 and the second NMOS tube MN2 are connected in parallel;
the gate of the second PMOS transistor MP2 is connected to a control signal, the drain of the second PMOS transistor MP2 is connected to the third resistor R3, and the source of the second PMOS transistor MP2 is connected to the fourth resistor R4;
the gate of the second NMOS transistor MN2 is connected to the inverted signal of the switch control signal.
In a preferred embodiment, the line driver 1 is a voltage-type line driver 1.
The line driver 1 of the invention is an impedance calibration overvoltage protection circuit, the line driver 1 being a voltage type line driver 1.
In the above preferred embodiment, a transformer or common mode coil 9 is connected between the first connection end and the second connection end, the transformer or common mode coil 9 is connected to the hybrid circuit 8, and a resistor with a resistance of 100ohm is further connected in parallel between the two ends of the transformer or common mode coil 9.
Example two
The invention also provides an impedance calibration overvoltage protection method for the line driver 1, which is characterized by being applied to the impedance calibration overvoltage protection circuit for the line driver 1, and the method comprises the following steps:
each first Transmission Gate (TG) is controllably opened or closed under the action of a switch control signal11…TG1i) So as to adjust the impedance between the line driver 1 and the first connection terminal of the hybrid circuit 8 to a preset value; and/or
Each second Transmission Gate (TG) is controllably switched on or off under the action of a switch control signal21…TG2i) To adjust the impedance between the line driver 1 and the second connection of the hybrid circuit 8 to a preset value;
as shown in fig. 6, the method further includes: detecting the amplitude of the opposite-end signal received by the hybrid circuit 8;
comparing the amplitude of the detected opposite terminal signal with a preset threshold value and outputting a comparison signal;
the amplitude of the local signal sent by the line driver 1 is controlled in accordance with the comparison signal.
As a preferred embodiment, among others, it further includes:
when the amplitude of the opposite-end signal is larger than a preset threshold value, controlling the amplitude of the transmitted local-end signal to be halved;
and when the amplitude of the opposite end signal is less than or equal to a preset threshold value, sending the opposite end signal according to the original amplitude of the local end signal.
Specifically, in this embodiment, amplitude limiting is performed on the local transmission amplitude, so that the swing amplitude at the transmission gate is small, the range of the operating voltage interval is small, and the transmission gate operates at the intermediate voltage, so that the power supply voltage of the transmission gate is always in the safety interval, and overvoltage protection is realized.
It should be noted that, in the embodiment of the present invention, a differential line driver is taken as an example, and the scheme of the present invention is also applicable to the single-ended line driver 1, that is, only one transmission line is provided, an impedance calibration circuit is designed on the transmission line to implement impedance calibration, and amplitude limiting is performed based on the detected amplitude to implement overvoltage protection of impedance calibration, which has a principle similar to that of the differential line driver 1 and is not described herein again.
Adopt above-mentioned technical scheme's beneficial effect to lie in: the impedance between the first connecting end and the second connecting end of the line driver and the hybrid circuit is limited to a preset value through the transmission gate, so that impedance calibration is realized, the range of the working voltage range is smaller, and the tolerance on the reliability of the Ethernet is better; and limiting the sending amplitude of the local terminal according to the sending amplitude of the opposite terminal by detecting the sending amplitude of the opposite terminal, thereby realizing the overvoltage protection of impedance calibration.
While the specification concludes with claims defining exemplary embodiments of particular structures for practicing the invention, it is believed that other modifications will be made in the spirit of the invention. While the above invention sets forth presently preferred embodiments, these are not intended as limitations.
Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above description. It is therefore intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention. Any and all equivalent ranges and contents within the scope of the claims should be considered to be within the intent and scope of the present invention.
Claims (10)
1. A line driver impedance calibration overvoltage protection circuit applied to Ethernet is characterized by comprising:
a first impedance calibration circuit connected between a line driver and a first connection of a hybrid circuit, the first impedance calibration circuit comprising:
the two ends of each first transmission gate are respectively connected with a first resistor and a second resistor, and each first transmission gate can be controllably switched on or switched off under the action of a switch control signal so as to adjust the impedance between the line driver and the first connection end to a preset value;
an overvoltage protection circuit connecting the line driver and the hybrid circuit, respectively, the overvoltage protection circuit comprising:
the amplitude detection circuit is used for detecting the amplitude of the opposite terminal signal received by the mixing circuit;
the digital control circuit is used for comparing the amplitude of the opposite end signal with a preset threshold value and outputting a comparison signal;
and the amplitude control circuit is used for controlling the amplitude of the local end signal sent by the line driver according to the comparison signal.
2. The line driver impedance calibration overvoltage protection circuit of claim 1, further comprising: a second impedance calibration circuit connected between the line driver and the second connection terminal of the hybrid circuit, the second impedance calibration circuit comprising:
and two ends of each second transmission gate are respectively connected with a third resistor and a fourth resistor, and each second transmission gate can be controllably switched on or switched off under the action of the switch control signal so as to adjust the impedance between the line driver and the second connecting end to the preset value.
3. The line driver impedance calibration overvoltage protection circuit of any one of claims 1 or 2, wherein when the amplitude of said opposite end signal is greater than said predetermined threshold, said amplitude control circuit controls the amplitude of the transmitted local end signal to be halved;
and when the amplitude of the opposite-end signal is less than or equal to the preset threshold value, sending the opposite-end signal according to the original amplitude of the local-end signal.
4. The line driver impedance calibration overvoltage protection circuit of claim 1, further comprising:
a first voltage dividing circuit for outputting a first intermediate voltage;
the second voltage division circuit is used for outputting a second intermediate voltage;
and the input end of the level conversion unit is respectively connected with the first voltage division circuit and the second voltage division circuit, and the output end of the level conversion unit is respectively connected with each first transmission gate and is used for switching between the first intermediate voltage and the second intermediate voltage so as to output the switch control signal, thereby controlling the branch circuit where each first transmission gate is located between the line driver and the first connection end to be respectively switched on or switched off.
5. The line driver impedance calibration overvoltage protection circuit of claim 1, wherein the first transmission gate comprises:
the source and drain electrodes are connected in parallel with a first PMOS tube and a first NMOS tube;
the grid electrode of the first PMOS tube is connected with the switch control signal, the drain electrode of the first PMOS tube is connected with the first resistor, and the source electrode of the first PMOS tube is connected with the second resistor;
and the grid electrode of the first NMOS tube is connected with the inverted signal of the switch control signal.
6. The line driver impedance calibration overvoltage protection circuit of claim 2, further comprising:
a first voltage dividing circuit for outputting a first intermediate voltage;
the second voltage division circuit is used for outputting a second intermediate voltage;
and an input end of the level conversion unit is connected to the first voltage division circuit and the second voltage division circuit, and an output end of the level conversion unit is connected to each of the second transmission gates, and is configured to switch between the first intermediate voltage and the second intermediate voltage to output the switch control signal, so as to control a branch where each of the second transmission gates is located between the line driver and the second connection end to be turned on or off.
7. The line driver impedance calibration overvoltage protection circuit of claim 2, wherein the second transmission gate comprises:
the source and drain electrodes of the second PMOS tube and the second NMOS tube are connected in parallel;
the grid electrode of the second PMOS tube is connected with the switch control signal, the drain electrode of the second PMOS tube is connected with the third resistor, and the source electrode of the second PMOS tube is connected with the fourth resistor;
and the grid electrode of the second NMOS tube is connected with the inverted signal of the switch control signal.
8. The line driver impedance calibration overvoltage protection circuit of claim 1, wherein the line driver is a voltage mode line driver.
9. A line driver impedance calibrated overvoltage protection method applied to a line driver impedance calibrated overvoltage protection circuit according to any one of claims 1 to 8, said method comprising:
each first transmission gate is controllably switched on or switched off under the action of a switch control signal so as to adjust the impedance between the line driver and the first connection end of the hybrid circuit to a preset value; and/or
Under the action of the switch control signal, each second transmission gate is controllably switched on or switched off so as to adjust the impedance between the line driver and the second connecting end of the hybrid circuit to the preset value;
further comprising: detecting the amplitude of an opposite end signal received by the hybrid circuit;
comparing the amplitude of the detected opposite-end signal with a preset threshold value and outputting a comparison signal;
and controlling the amplitude of the local end signal sent by the line driver according to the comparison signal.
10. The line driver impedance calibration over-voltage protection method of claim 9, further comprising:
when the amplitude of the opposite-end signal is larger than the preset threshold value, controlling the amplitude of the transmitted local-end signal to be halved;
and when the amplitude of the opposite-end signal is less than or equal to the preset threshold value, sending the opposite-end signal according to the original amplitude of the local-end signal.
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| CN202210178186.4A CN114744992A (en) | 2022-02-24 | 2022-02-24 | Circuit driver impedance calibration overvoltage protection circuit and method |
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| CN202210178186.4A CN114744992A (en) | 2022-02-24 | 2022-02-24 | Circuit driver impedance calibration overvoltage protection circuit and method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115149775A (en) * | 2022-08-12 | 2022-10-04 | 南京金阵微电子技术有限公司 | Correction circuit and correction method based on interface drive circuit |
| CN117434333A (en) * | 2023-12-01 | 2024-01-23 | 深圳智芯微电子科技有限公司 | Micro-grid line voltage abnormality detection circuit, energy management system and electric equipment |
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2022
- 2022-02-24 CN CN202210178186.4A patent/CN114744992A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115149775A (en) * | 2022-08-12 | 2022-10-04 | 南京金阵微电子技术有限公司 | Correction circuit and correction method based on interface drive circuit |
| CN115149775B (en) * | 2022-08-12 | 2023-10-20 | 南京金阵微电子技术有限公司 | Correction circuit and correction method based on interface driving circuit |
| CN117434333A (en) * | 2023-12-01 | 2024-01-23 | 深圳智芯微电子科技有限公司 | Micro-grid line voltage abnormality detection circuit, energy management system and electric equipment |
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