CN105577137B - For automatically correcting the transmission line drive circuit of impedance matching - Google Patents
For automatically correcting the transmission line drive circuit of impedance matching Download PDFInfo
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- CN105577137B CN105577137B CN201410531264.XA CN201410531264A CN105577137B CN 105577137 B CN105577137 B CN 105577137B CN 201410531264 A CN201410531264 A CN 201410531264A CN 105577137 B CN105577137 B CN 105577137B
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Abstract
It proposes a kind of for automatically correcting the transmission line drive circuit of impedance matching, comprising: the transmission line driving amplifier with the first transmission end and the second transmission end；First signal node；Second signal node；The first adjustable resistance between the first transmission end and the first signal node；The second adjustable resistance between the second transmission end and second signal node；It is coupled to the first voltage difference generation circuit at the first adjustable resistance both ends, for generating first voltage difference；It is coupled to the second voltage difference generation circuit at the both ends of the second adjustable resistance, for generating second voltage difference；First sampling and holding circuit, for generating the first sampled signal according to first voltage difference；Second sampling and holding circuit, for generating the second sampled signal according to second voltage difference；Comparison circuit, for comparing the first sampled signal and the second sampled signal；And adjustment circuit, for according at least one of the comparison result of comparison circuit the first adjustable resistance of adjustment and the second adjustable resistance.
Description
Technical field
The present invention relates to transmission line drive circuit more particularly to a kind of transmission line of automatically calibrating impedance matching driving electricity
Road.
Background technique
In order to transmit signal and energy efficient, ideally circuit of output terminal and inlet circuit preferably work in impedance
Matching status.That is, the internal resistance of circuit of output terminal should be equal to the input impedance of circuit of output terminal, and the output of circuit of output terminal
Impedance should be equal to the impedance of inlet circuit (also commonly referred to as loading).When the resistance of both circuit of output terminal and inlet circuit
It is anti-when matching each other, maximum power transmission will be obtained.Conversely, when both circuit of output terminal and inlet circuit impedance not
Timing not only cannot get maximum power transmission, it is also possible to generate damage to circuit.
For example, when the impedance mismatch of both circuit of output terminal and inlet circuit, the differential input of circuit of output terminal
Out electric current have it is asymmetric happen, and then the problem of lead to electromagnetic interference (EMI).In addition, when circuit of output terminal with it is defeated
When the impedance mismatch of both input circuits, the reflection loss (Return Loss) of system also be will increase.
Summary of the invention
In consideration of it, the case where circuit of output terminal and inlet circuit impedance mismatch how is effectively mitigated or eliminated, with drop
The problem of low EMI and reflection loss is this field problem to be solved.
This specification provides a kind of for automatically correcting the embodiment of the transmission line drive circuit of impedance matching, packet
Include: transmission line driving amplifier has for providing the first transmission end and the second transmission end of a pair of differential formula transmission signal；The
One signal node, for coupling the first load end signal node of equivalent load circuit；Second signal node, it is equivalent for coupling
Second load end signal node of load circuit；First adjustable resistance, between the first transmission end and the first signal node
On signal path；Second adjustable resistance, on the signal path between the second transmission end and second signal node；First voltage
Difference generation circuit is coupled to the both ends of the first adjustable resistance, is arranged to generate first voltage difference；Second voltage difference generates
Circuit is coupled to the both ends of the second adjustable resistance, is arranged to generate second voltage difference；First sampling and holding circuit, coupling
In first voltage difference generation circuit, it is arranged to carry out first voltage difference sampling and keep operating, to generate the first sampling
Signal；Second sampling and holding circuit, are coupled to second voltage difference generation circuit, are arranged to adopt second voltage difference
Sample and holding operate, to generate the second sampled signal；Comparison circuit, be coupled to the first sampling and holding circuit and the second sampling with
Holding circuit is arranged to compare the first sampled signal and the second sampled signal；And adjustment circuit, it is coupled to the first adjustable electric
Resistance, the second adjustable resistance and comparison circuit are arranged to the comparison result according to comparison circuit, adjust the first adjustable resistance and the
At least one of resistance value of two adjustable resistances.
The advantages of above embodiment first is that transmission line drive circuit can reduce or eliminate the first signal node and second
The asymmetric situation of output electric current between signal node, and then the problem of reduction electromagnetic interference and reflection loss.
Another advantage of above embodiment is that transmission line drive circuit automatically, can be corrected effectively and equivalent load circuit
Between impedance mismatch situation, and suitable for the structure of various circuit of output terminal, therefore, application range is quite extensive.
Other advantages of the invention will be explained in more detail by the following description and attached drawing.
Detailed description of the invention
Fig. 1 is the simplified functional block diagram of transmission line drive circuit of embodiments of the present invention.
Specific embodiment
Illustrate embodiments of the present invention below in conjunction with relevant drawings.In the accompanying drawings, identical label indicates identical
Or similar element or method flow.
Fig. 1 is transmission line drive circuit (the transmission line driver of embodiments of the present invention
Circuit) 100 simplified functional block diagram.As shown in Figure 1, transmission line drive circuit 100 includes transmission line driving amplifier
(transmission line driving amplifier) the 110, first signal node (signal node) 122, second letter
Number node 124, the first adjustable resistance 132, the second adjustable resistance 134, first voltage difference generation circuit (signal
Difference generating circuit) 142, second voltage difference generation circuit 144, first sampling and holding circuit
152, the second sampling and holding circuit 154, comparison circuit 160 and adjustment circuit 170.
There is transmission line driving amplifier 110 the first transmission end for providing a pair of differential formula transmission signal to pass with second
Defeated end.In the present embodiment, aforementioned first transmission end is the positive output end of transmission line driving amplifier 110, and aforementioned second
Transmission end is the negative output terminal of transmission line driving amplifier 110.First signal node 122 is for coupling equivalent load circuit
The first load end signal node (load-end signal node) 181 of (equivalent load circuit) 180.The
Binary signal node 124 is used to couple the second load end signal node 182 of equivalent load circuit 180.In fact, the first signal section
Point 122 can be respectively coupled to the first load end signal node 181 by various pairs of signal wires with second signal node 124
With the second load end signal node 182.In operation, the first signal node 122 can drive transmission line with second signal node 124
The differential type that dynamic amplifier 110 generates transmits signal, is respectively sent to the first load end signal node of equivalent load circuit 180
181 and the second load end signal node 182.
" equivalent load circuit " word so-called in the specification and in the claims, can be amplification in practical application
The various inlet circuits of device, circuit under test, antenna or receiver etc..For the sake of for convenience of description, especially will in Fig. 1
The function block of equivalent load circuit 180 is simplified.In equivalent load circuit 180, load end equivalent capacity 183 represents
The equivalent capacity on signal path where one load end signal node 181, load end equivalent impedance 185 represent the first load end
The equivalent impedance on signal path where signal node 181.Similarly, load end equivalent capacity 184 represents the second load end
The equivalent capacity on signal path where signal node 182, load end equivalent impedance 186 represent the second load end signal node
The equivalent impedance on signal path where 182.
In addition, aforementioned first signal node 122 and second signal node 124, can be medium correlation in practical application
A pair of differential formula signal node in interface (medium dependent interface, MDI), can be cross connection type medium phase
A pair of differential formula signal node in interface (medium dependent interface crossover, MDIX) is closed, it can also
To be a pair of differential formula signal node in other signal transmission interfaces.Similarly, aforementioned first load end signal node 181 with
Second load end signal node 182 can be a pair of differential formula signal node in medium dependent interfaces in practical application, can
To be a pair of differential formula signal node in cross connection type medium dependent interfaces, a pair being also possible in other signal transmission interfaces
Differential signal node.
In the present embodiment, the first end of the first adjustable resistance 132 is coupled to the first of transmission line driving amplifier 110
The positive input terminal of transmission end and first voltage difference generation circuit 142, and the second end of the first adjustable resistance 132 is coupled to
The negative input end of one signal node 122 and first voltage difference generation circuit 142.The first end coupling of second adjustable resistance 134
It is connected to the second transmission end of transmission line driving amplifier 110 and the positive input terminal of second voltage difference generation circuit 144, and
The second end of two adjustable resistances 134 is coupled to the negative input of second signal node 124 and second voltage difference generation circuit 144
End.
In other words, in transmission line drive circuit 100, the first adjustable resistance 132 is located at the first transmission end and the first signal
On signal path between node 122, the second adjustable resistance 134 is then between the second transmission end and second signal node 124
Signal path on, first voltage difference generation circuit 142 is coupled to the both ends of the first adjustable resistance 132, and second voltage is poor
Value generation circuit 144 is coupled to the both ends of the second adjustable resistance 134.
First voltage difference generation circuit 142 is arranged to generate first voltage difference VPD, and second voltage difference generates electricity
Road 144 is then arranged to generate second voltage difference VND.In the present embodiment, first voltage difference generation circuit 142 can calculate
Voltage between the voltage VP1 of the second end of the voltage VP0 of the first end of first adjustable resistance 132 and the first adjustable resistance 132
Difference, to generate first voltage difference VPD.Second voltage difference generation circuit 144 can calculate the first end of the second adjustable resistance 134
Voltage VN0 and the second adjustable resistance 134 second end voltage VN1 between voltage difference, to generate second voltage difference
VND.Therefore, first voltage difference VPD represents the voltage difference at 132 both ends of the first adjustable resistance, and second voltage difference VND then generation
The voltage difference at 144 both ends of table second voltage difference generation circuit.
First sampling is coupled to first voltage difference generation circuit 142 with holding circuit 152, and it is poor to first voltage to be arranged to
Value VPD carries out sampling and keeps operating, to generate the first sampled signal SHP according to first voltage difference VPD.Second sampling and guarantor
It holds circuit 154 and is coupled to second voltage difference generation circuit 144, be arranged to that second voltage difference VND is sampled and kept
Operation, to generate the second sampled signal SHN according to second voltage difference VND.
Comparison circuit 160 is coupled to the defeated of the first sampling and holding circuit 152 and the second sampling and 154 the two of holding circuit
Outlet is arranged to compare the size of the first sampled signal SHP and the second sampled signal SHN.In the present embodiment, comparison circuit
160 positive input terminal is coupled to the output end of the first sampling Yu holding circuit 152, and the negative input end of comparison circuit 160 couples
In the output end of the second sampling and holding circuit 154.
Adjustment circuit 170 is coupled to the first adjustable resistance 132, the second adjustable resistance 134 and comparison circuit 160, is arranged to
According to the comparison result of comparison circuit 160, to adjust at least one of of the first adjustable resistance 132 and the second adjustable resistance 134
A resistance value.
In fact, adjustment circuit 170 can use various groups of various logic circuit, digital circuit, counter or aforementioned circuit
It closes to realize.In some embodiments, may also include in adjustment circuit 170 can storing data storage circuit (not shown),
For example, buffer, buffer, flip-flop, memory etc..
In ideal conditions, when the impedance matching of 180 the two of transmission line drive circuit 100 and equivalent load circuit,
Voltage difference between the voltage VP0 and VP1 at 132 both ends of the first adjustable resistance, it should the voltage with 134 both ends of the second adjustable resistance
Voltage difference between VN0 and VN1 is equal, and therefore, the size of both the first sampled signal SHP and second sampled signal SHN should
It is equal.
Therefore, as the output of comparison circuit 160 both first sampled signal SHP and the second sampled signal SHN as the result is shown
And when unequal, adjustment circuit 170 judges the impedance of both transmission line drive circuit 100 at this time and equivalent load circuit 180
Do not match.In the case, adjustment circuit 170 can be by adjusting the first adjustable resistance 132 and the second adjustable resistance 134 extremely
The mode of the resistance value of one of them less, the output impedance of Lai Jiaozheng transmission line drive circuit 100, so that transmission line drives
Both circuit 100 and equivalent load circuit 180 reach the state of impedance matching.
For example, when comparison circuit 160 judges that the first sampled signal SHP is greater than the second sampled signal SHN, adjustment circuit
170 can reduce the resistance value of the first adjustable resistance 132 or increase the resistance value of the second adjustable resistance 134.Conversely, working as comparison circuit
160 when judging the first sampled signal SHP less than the second sampled signal SHN, and adjustment circuit 170 can then reduce the first adjustable resistance
132 resistance value or the resistance value for increasing by the second adjustable resistance 134.
Both the first sampled signal SHP and the second sampled signal SHN are only able to display in the output result of comparison circuit 160
In the certain embodiments of relative size, adjustment circuit 170 can gradually reduce the first adjustable resistance 132 in multiple calibration cycles
Resistance value or be stepped up the resistance value of the second adjustable resistance 134, until the output polarity of comparison circuit 160 changes.
The phase of both the first sampled signal SHP and the second sampled signal SHN can be shown in the output result of comparison circuit 160
To in the certain embodiments of size and measures of dispersion, adjustment circuit 170 can also directly can by first in single calibration cycle
It adjusts the resistance value of resistance 132 to be reduced to first object value, or the resistance value of the second adjustable resistance 134 is directly increased to second
Target value.For example, can be corresponding with resistance value adjustment amount with the measures of dispersion of the second sampled signal SHN by the first sampled signal SHP
Relationship is indicated in the form of table of comparisons (not shown), and is stored in advance in the storage circuit of adjustment circuit 170.In operation,
Adjustment circuit 170 can inquire the table of comparisons according to the measures of dispersion of the first sampled signal SHP and the second sampled signal SHN to obtain
Resistance value adjustment amount appropriate, and at least one of of the first adjustable resistance 132 and the second adjustable resistance 134 is adjusted accordingly
Resistance value.
By preceding description it is found that the comparison circuit 160 in transmission line drive circuit 100 can detect transmission line drive circuit
Whether 100 reach the state of impedance matching with equivalent load circuit 180 between the two.If the comparison result of comparison circuit 160 is aobvious
Show that the impedance of both transmission line drive circuit 100 and equivalent load circuit 180 does not match, then adjustment circuit 170 can pass through tune
The mode of at least one of resistance value of whole first adjustable resistance 132 and the second adjustable resistance 134, Lai Jiaozheng transmission line drive
The output impedance of dynamic circuit 100.By this method, transmission line drive circuit 100 and equivalent load electricity just can automatically, effectively be corrected
Impedance mismatch situation between road 180, so that both transmission line drive circuit 100 and equivalent load circuit 180 reach impedance
Matched state.
Aforementioned adjustment circuit 170 adjusts the first adjustable resistance 132 and second according to the comparison result of comparison circuit 160 can
The operation for adjusting at least one of resistance value of resistance 134, also can reduce or eliminate the first signal node 122 and second signal
The asymmetric situation of output electric current between node 124, therefore, the problem of electromagnetic interference and reflection loss can be effectively reduced.
In addition, therefore the structure that the structure of aforementioned transmission line drive circuit 100 is suitable for various circuit of output terminal is answered
It is related extensively with range.
Certain words are used in the specification and in the claims to specify specific element.However, affiliated technology neck
Domain one of ordinary skill appreciates that, same element may be called with different nouns.Specification and claims are simultaneously
Not in such a way that the difference of title is as element is distinguished, but carry out the benchmark as differentiation with the difference of element functionally.?
" comprising " mentioned in specification and claims is therefore open term should be construed to " including but not limited to ".
In addition, " coupling " includes any connection means directly or indirectly herein.Therefore, if it is described herein that first element is coupled to second
Element, then represent first element can by being electrically connected or being wirelessly transferred, the signals connection type such as optical delivery is directly connected
In second element, or by other elements or connection means, electricity or signal are connected to second element indirectly.
The describing mode of "and/or" used herein, any group including wherein one or more cited projects
It closes.In addition, unless specified in the instructions, otherwise the word of any singular all includes the meaning of plural form simultaneously.
The above is only better embodiment of the invention, all changes that all claims according to the present invention are done with repair
Change, all should belong to coverage area of the invention.
Claims (6)
1. a kind of transmission line drive circuit of automatically calibrating impedance matching, comprising:
Transmission line driving amplifier has for providing the first transmission end and the second transmission end of a pair of differential formula transmission signal；
First signal node, for coupling the first load end signal node of equivalent load circuit；
Second signal node, for coupling the second load end signal node of the equivalent load circuit；
First adjustable resistance, one end are connected to first transmission end, and the other end is connected to first signal node；
Second adjustable resistance, one end are connected to second transmission end, and the other end is connected to the second signal node；
First voltage difference generation circuit is coupled to the both ends of first adjustable resistance, is arranged to generate first voltage difference；
Second voltage difference generation circuit is coupled to the both ends of second adjustable resistance, is arranged to generate second voltage difference；
First sampling and holding circuit, are coupled to the first voltage difference generation circuit, it is poor to the first voltage to be arranged to
Value carries out sampling and keeps operating, to generate the first sampled signal；
Second sampling and holding circuit, are coupled to the second voltage difference generation circuit, it is poor to the second voltage to be arranged to
Value carries out sampling and keeps operating, to generate the second sampled signal；
Comparison circuit is coupled to first sampling and holding circuit and second sampling and holding circuit, is arranged to compare
First sampled signal and second sampled signal；And
Adjustment circuit is coupled to first adjustable resistance, second adjustable resistance and the comparison circuit, is arranged to root
According to the comparison result of the comparison circuit, at least one of which of first adjustable resistance and second adjustable resistance is adjusted
Resistance value.
2. transmission line drive circuit according to claim 1, wherein when the comparison circuit judges the first sampling letter
Number be greater than second sampled signal when, the adjustment circuit can reduce described in the resistance value or increase of first adjustable resistance
The resistance value of second adjustable resistance.
3. transmission line drive circuit according to claim 2, wherein the adjustment circuit is arranged in multiple calibration cycles
In gradually reduce the resistance value of first adjustable resistance or be stepped up the resistance value of second adjustable resistance, until described
Until the output polarity of comparison circuit changes.
4. transmission line drive circuit according to claim 2, wherein the adjustment circuit is arranged in single calibration cycle
In the resistance value of first adjustable resistance is directly reduced to first object value, or directly by second adjustable resistance
Resistance value increases to the second target value.
5. transmission line drive circuit according to claim 1, wherein first signal node and the second signal section
Point is a pair of differential formula signal node in medium dependent interfaces.
6. transmission line drive circuit according to claim 1, wherein first signal node and the second signal section
Point is a pair of differential formula signal node in cross connection type medium dependent interfaces.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410531264.XA CN105577137B (en) | 2014-10-10 | 2014-10-10 | For automatically correcting the transmission line drive circuit of impedance matching |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410531264.XA CN105577137B (en) | 2014-10-10 | 2014-10-10 | For automatically correcting the transmission line drive circuit of impedance matching |
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| CN105577137A CN105577137A (en) | 2016-05-11 |
| CN105577137B true CN105577137B (en) | 2019-05-10 |
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| CN115035833B (en) * | 2022-05-12 | 2023-06-16 | 重庆惠科金渝光电科技有限公司 | Control circuit, signal control circuit and display device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101587753A (en) * | 2009-06-26 | 2009-11-25 | 北京中星微电子有限公司 | A kind of simulating signal sample circuit and a kind of switched-capacitor circuit |
| CN102468840A (en) * | 2010-11-04 | 2012-05-23 | 联发科技股份有限公司 | Differential driver with calibration circuit and related calibration method |
| CN103414474A (en) * | 2013-08-27 | 2013-11-27 | 成都启臣微电子有限公司 | High-precision small-signal difference analog-digital converter |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030085737A1 (en) * | 2001-11-08 | 2003-05-08 | Tinsley Steven J. | Innovative high speed LVDS driver circuit |
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2014
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101587753A (en) * | 2009-06-26 | 2009-11-25 | 北京中星微电子有限公司 | A kind of simulating signal sample circuit and a kind of switched-capacitor circuit |
| CN102468840A (en) * | 2010-11-04 | 2012-05-23 | 联发科技股份有限公司 | Differential driver with calibration circuit and related calibration method |
| CN103414474A (en) * | 2013-08-27 | 2013-11-27 | 成都启臣微电子有限公司 | High-precision small-signal difference analog-digital converter |
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