CN102857450B

CN102857450B - Line driver and protection method thereof

Info

Publication number: CN102857450B
Application number: CN201210173621.0A
Authority: CN
Inventors: 赵治磊
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2012-05-30
Filing date: 2012-05-30
Publication date: 2015-07-22
Anticipated expiration: 2032-05-30
Also published as: CN102857450A

Abstract

The invention discloses a line driver and a protection method thereof and belongs to the communication field. The line driver comprises a main body module, a signal acquisition module, a signal judging module and a control signal generating module, wherein the main body module comprises a first switching tube and a second switching tube which are connected in series, an intermediate node of the first switching tube and the second switching tube which are connected in series is taken as an output terminal of the main body module; the signal acquisition module is used for acquiring an output signal which flows through the output terminal of the main body module; the signal judging module is used for judging whether a signal value of the output signal is higher than a first preset threshold or lower than a second preset threshold; and the control signal generating module is used for generating a first control signal to switch on the second switch tube when the signal value of the output signal is higher than the first preset threshold and generating a second control signal to switch on the first switch tube when the signal value of the output signal is lower than the first preset threshold. According to the technical scheme, the switch tubes are taken as discharge channels of an output signal of an external line, and protection capability of the line driver is effectively enhanced.

Description

Line driver and means of defence thereof

Technical field

The present invention relates to the communications field, particularly a kind of line driver and means of defence thereof.

Background technology

XDSL is the general name of all kinds DSL (Digital Subscriber Line, digital subscriber line), comprises ADSL, RADSL, VDSL, SDSL, IDSL and HDSL etc.In xDSL system, line driver is arranged in the active parts of afterbody for power amplification, and it is sent on outside line through transformer coupled after being amplified by signal.Also mean on the other hand, if outside line has interference signal, interference signal also can be directly coupled to the output of line driver by transformer, the protection therefore for line driver is one of emphasis of xDSL systematic protection.

Please refer to Fig. 1, it illustrates a kind of circuit diagram comprising the line driver of protection module of the prior art.This line driver is Class H line driver, also claims pungent class line driver, and be a kind of line driver carrying out improving based on Class AB line driver, Class AB line driver also claims class AB line start device.

This Class H line driver comprises the first main body module 120, second main body module 140, first electric charge pump module 122, second electric charge pump module 142 and protection module 160.Wherein, first main body module 120 comprises the first triode Q1 and the second triode Q2 (other element does not specifically illustrate) of series connection, the emitter of the first triode Q1 is connected with the emitter of the second triode Q2, and the node E be connected is as an output of this line driver, the voltage at node E place as an output voltage of this line driver, an also output of i.e. this line driver.Under normal circumstances, the output of the first main body module 120 is also in series with the first resistance R1 simultaneously, and the first resistance R1 can realize impedance matching function, suppresses the reflected signal of load end.Similarly, second main body module 140 comprises the 3rd triode Q3 and the 4th triode Q4 (other element does not specifically illustrate) of series connection, the emitter of the 3rd triode Q3 is connected with the emitter of the 4th triode Q4, and the node F be connected is as an output of this line driver, the voltage at node F place is as another output voltage of this line driver.Under normal circumstances, the output of the second main body module 140 is also in series with the second resistance R2 simultaneously, and the second resistance R2 also can realize impedance matching function, suppresses the reflected signal of load end.Said structure is basic identical with Class AB line driver.

This Class H line driver and Class AB line driver unlike: this Class H line driver also includes the first electric charge pump module 122 and the second electric charge pump module 142.Include a first diode D1 in this first electric charge pump module 122, in this second electric charge pump module 142, include a second diode D2.When the input signal that this Class H line driver transmission voltage swing is less, positive supply VS+ and negative supply VS-powers to the first main body module 120 and the second main body module 140 by the first diode D1 in two electric charge pump module and the second diode D2.When the input signal that this Class H line driver transmission voltage swing is larger, two electric charge pump module can exceed according to input signal the supply power voltage that threshold values partial linear adjusts the first main body module 120 and the second main body module 140, make the supply power voltage of the first main body module 120 and the second main body module 140 can follow the voltage waveform of output signal, thus input signal larger for voltage swing is normally sent.

The current conventional protection module for Class H line driver is as shown in protection module 160, namely between the first main body module 120 and two difference output ends of the second main body module 140, a transient voltage suppressor is connected (English: TRANSIENT VOLTAGE SUPPRESSOR, be called for short: TVS pipe), TVS pipe is equivalent to the diode of two differential concatenations.

Because TVS pipe is voltage regulation type device, the operation voltage of the TVS pipe selected at above-mentioned line driver must higher than the maximum output voltage of line driver, therefore the ability of its abnormal signal of releasing is more weak, in other words, when the magnitude of voltage of abnormal signal is less than the operation voltage of TVS pipe, then cannot to release this abnormal signal, to cause abnormal signal of can not effectively releasing.

Summary of the invention

In order to solve the poor problem of the protective capacities of TVS pipe to abnormal signal, embodiments provide a kind of line driver and means of defence thereof.Described technical scheme is as follows:

According to an aspect of the present invention, embodiments provide a kind of line driver, this line driver comprises:

Main body module, comprise the first switching tube and the second switch pipe of series connection, described first switching tube is also connected with positive supply, and described second switch pipe is also connected with negative supply, and the first switching tube of described series connection and the intermediate node of second switch pipe are as the output of described main body module;

Signal acquisition module, for gathering the output signal of the output of described main body module;

Signal judge module, for judging that whether the signal value of described output signal is higher than the first reservation threshold, or lower than the second reservation threshold;

Control signal generation module, for determine described output signal at described signal judge module signal value higher than described first reservation threshold time, produce the first control signal making the conducting of described second switch pipe; Or when the signal value that described signal judge module determines described output signal is lower than described second reservation threshold, produce the second control signal making described first switching tube conducting.

According to a further aspect in the invention, the embodiment of the present invention also provides a kind of line driver, and this line driver comprises:

First main body module, comprises the first switching tube and the second switch pipe of series connection, and the first switching tube of described series connection and the intermediate node of second switch pipe are as the difference output end of described first main body module;

Second main body module, comprises the 3rd switching tube and the 4th switching tube of series connection, and the 3rd switching tube of described series connection and the intermediate node of the 4th switching tube are as the output of described second main body module;

First signal acquisition module, for gathering the output signal of the output of described first main body module;

Secondary signal acquisition module, for gathering the output signal of the output of described second main body module;

First signal judge module, for judging that whether the signal value of the output signal that described first signal acquisition module gathers is higher than the first reservation threshold, or lower than the second reservation threshold;

Secondary signal judge module, for judging that whether the signal value of the output signal that described secondary signal acquisition module gathers is higher than the 3rd reservation threshold, or lower than the 4th reservation threshold;

Control signal generation module, during for determining the signal value of output signal that described first signal acquisition module gathers at described first signal judge module higher than described first reservation threshold, or when described secondary signal judge module determines the signal value of output signal that described secondary signal acquisition module gathers lower than described 4th reservation threshold, produce the 3rd control signal making the conducting of described second switch pipe and described 3rd switching tube conducting;

When described first signal judge module determines the signal value of output signal that described first signal acquisition module gathers lower than described second reservation threshold, or when described secondary signal judge module determines the signal value of output signal that described secondary signal acquisition module gathers higher than the 3rd reservation threshold, produce the 4th control signal making described first switching tube conducting and described 4th switching tube conducting;

Wherein, described first switching tube is also connected with positive supply with described 3rd switching tube, and described second switch pipe is also connected with negative supply with the 4th switching tube; Described signal value is magnitude of voltage or performance number.

In accordance with a further aspect of the present invention, the embodiment of the present invention also provides a kind of means of defence of line driver, for in the line driver of the first switching tube and second switch pipe that comprise series connection, the intermediate node of described first switching tube and second switch pipe is the output of described line driver, and described method comprises:

Gather the output signal of the output of described line driver;

Judge that whether the signal value of described output signal is higher than the first reservation threshold, or lower than the second reservation threshold;

If when the signal value of described output signal is higher than the first reservation threshold, produce the first control signal making the conducting of described second switch pipe;

If when the signal value of described output signal is lower than the second reservation threshold, produce the second control signal making described first switching tube conducting.

The beneficial effect that the technical scheme that the embodiment of the present invention provides is brought is:

By increasing signal acquisition module, signal judge module and control signal generation module, the output switch pipe in line driver can be utilized to be used as the leakage path of the abnormal signal of outside line, the output switch pipe in line driver is utilized inherently to have the feature of stronger power bearing ability, solve the problem that the protective capacities of TVS pipe to abnormal signal is poor, reach the beneficial effect of the protective capacities effectively strengthening line driver.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, below the accompanying drawing used required in describing embodiment is briefly described, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1 is the circuit diagram of a kind of line driver of the prior art;

Fig. 2 is the circuit diagram of the line driver that the embodiment of the present invention one provides;

Fig. 3 is the circuit diagram of the line driver that the embodiment of the present invention two provides;

Fig. 4 is the circuit diagram of the attenuation units that the embodiment of the present invention two provides;

Fig. 5 is the circuit diagram of the line driver that the embodiment of the present invention three provides;

Fig. 6 is a kind of block diagram of the first signal judge module that the embodiment of the present invention three provides;

Fig. 7 is the another kind of block diagram of the first signal judge module that the embodiment of the present invention three provides;

Fig. 8 is a kind of block diagram of the secondary signal judge module that the embodiment of the present invention three provides;

Fig. 9 is the another kind of block diagram of the secondary signal judge module that the embodiment of the present invention three provides;

Figure 10 is the method flow diagram of the means of defence of the line driver that the embodiment of the present invention four provides.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, embodiment of the present invention is described further in detail.

Because line driver is originally as power amplifying device, the ability of bearing power of the triode of its output stage is stronger.Therefore the embodiment of the present invention utilizes the leakage path of output switch pipe as the abnormal signal of outside line of the output stage of line driver.

Embodiment one

Please refer to Fig. 2, it illustrates the circuit diagram of the line driver that the embodiment of the present invention one provides.This present embodiment one may be used for the protection to Class H line driver.This line driver comprises main body module 210, first electric charge pump module 220, second electric charge pump module 230, signal acquisition module 240, signal judge module 250 and control signal generation module 260.

Main body module 210 comprises the first switching tube Q1 and the second switch pipe Q2 (other element does not specifically illustrate) of series connection.First switching tube Q1 and second switch pipe Q2 can be the output switch pipe in Class H line driver.In one embodiment, first switching tube Q1 and second switch pipe Q2 can be triode, such as the first switching tube Q1 is NPN transistor, second switch pipe Q2 is PNP transistor, for ease of describing, in the embodiment of the present invention, respectively the first switching tube Q1 and second switch pipe Q2 is called the first triode Q1 and the second triode Q2.The emitter of the first triode Q1 is connected with the emitter of the second triode Q2, the collector electrode of the first triode Q1 is connected with positive supply VS+ by the first electric charge pump module 220, the collector electrode of the second triode Q2 is connected with negative supply VS-by the second electric charge pump module 230, and the intermediate node E place that the emitter of the first triode Q1 is connected with the emitter of the second triode Q2 is as an output of this line driver.The base stage of the first triode Q1 and the base stage of the second triode Q2 can respectively as the control ends of the first triode Q1 and the second triode Q2, be connected to control signal generation module 260, for the control signal being used for control first triode Q1 and the second triode Q2 on off state that reception control signal generation module 260 exports.Under normal circumstances, the output of main body module 210 is also in series with one end of the first resistance R1 simultaneously, and the first resistance R1 can realize impedance matching function, suppresses the reflected signal of load end.

First electric charge pump module 220 comprises the first diode D1, and the positive pole of the first diode D1 is connected with positive supply VS+, and the negative pole of the first diode D2 is connected with the collector electrode of the first triode Q1.

Second electric charge pump module 230 comprises the second diode D2, and the negative pole of the second diode D2 is connected with negative supply VS-, and the positive pole of the second diode D2 is connected with the collector electrode of the second triode Q2.

Signal acquisition module 240 is for the output signal of acquisition stream through the output of main body module 210.Specifically, the magnitude of voltage at the intermediate node E place that the emitter that signal acquisition module 240 can gather the first triode Q1 is connected with the emitter of the second triode Q2 or performance number are as the signal value outputed signal.

Signal judge module 250 judges that whether the signal value of the output signal that signal acquisition module 240 gathers is higher than the first predetermined threshold, or lower than the second predetermined threshold.Specifically, signal judge module 250 can comprise reference source generation unit 252 and signal comparing unit 254.

Reference source generation unit 252 is for generating the reference signal of sign first predetermined threshold Vref1 and the second predetermined threshold Vref2, under normal circumstances, first predetermined threshold Vref1 is greater than the second predetermined threshold Vref2, first predetermined threshold Vref1 and the second predetermined threshold Vref2 can think to judge that output signal is the need of the upper-lower door limit value of releasing, and namely the first predetermined threshold Vref1 and the second predetermined threshold Vref2 defines a normal signal scope.Reference source generation unit 252 can realize based on current source or voltage source circuit.

The reference signal that signal comparing unit 254 produces for the output signal that signal acquisition module 240 gathered and reference source generation unit 252 compares, to judge that whether the signal value outputed signal is higher than the first predetermined threshold Vref1, or lower than the second predetermined threshold Vref2, namely judge whether signal value exceeds above-mentioned normal signal scope, in embodiments of the present invention, if the signal value of output signal is higher than the first predetermined threshold Vref1, or lower than the second predetermined threshold Vref2, then above-mentioned output signal is abnormal signal, the signal value wherein outputed signal can be magnitude of voltage or performance number.If the signal value of output signal is magnitude of voltage, signal comparing unit 254 can realize based on voltage comparator circuit.

Control signal generation module 260 can be simple logic circuit or microprocessor.Control signal generation module 260 can when signal comparing unit 254 judges that the signal value that acquisition module 240 gathers exceeds above-mentioned normal signal scope, control signal is exported to the first switching tube Q1 or second switch pipe Q2, control one of them switching tube (i.e. the first switching tube Q1 or second switch pipe Q2) conducting to form signal leakage path, the output for this line driver carries out abnormal signal and releases.

Specifically, on the one hand, control signal generation module 260 for determine output signal at signal judge module 250 signal value higher than the first predetermined threshold Vref1 time, produce the first control signal controlling second switch pipe Q2 conducting.Now, output signal the negative supply VS-that released to by the second diode D2 in second switch pipe Q2 and the second electric charge pump module 230.

On the other hand, when the signal value that control signal generation module 260 also can determine output signal at signal judge module 250 is lower than the second predetermined threshold Vref2, produce the second control signal of control first switching tube Q1 conducting.Now, output signal the positive supply VS+ that released to by the first diode D1 in the first switching tube Q1 and the first electric charge pump module 220.

It should be noted that, above-mentioned modules all can be implemented in the inside of ClassH line driver; Also part of module can be implemented in the inside of ClassH line driver, and another part module is implemented in the outside of ClassH line driver.In addition, although the present embodiment is for ClassH line driver, obviously it will be appreciated by those of skill in the art that the scheme that the present embodiment provides also can use for ClassAB line driver.

In sum, the line driver that the embodiment of the present invention one provides, by increasing signal acquisition module, signal judge module and control signal generation module, can utilize the output switch pipe in line driver to be used as the leakage path of the output signal of outside line.Utilize the output switch pipe in line driver inherently to have the feature of stronger power bearing ability, solve the problem that the protective capacities of TVS pipe to output signal is poor, reach the beneficial effect of the protective capacities effectively strengthening line driver.

Embodiment two

Please refer to Fig. 3, it illustrates the circuit diagram of the line driver that the embodiment of the present invention two provides.The present embodiment two also may be used for the protection to Class H line driver.This line driver comprises main body module 310, first electric charge pump module 320, second electric charge pump module 330, signal acquisition module 340, signal judge module 350 and control signal generation module 360.

Main body module 310 comprises the first switching tube Q1 and the second switch pipe Q2 (other element does not specifically illustrate) of series connection.When the first switching tube Q1 and second switch pipe Q2 is triode, the emitter of the first triode Q1 is connected with the emitter of the second triode Q2, the collector electrode of the first triode Q1 is connected with positive supply VS+ by the first electric charge pump module 320, the collector electrode of the second triode Q2 is connected with negative supply VS-by the second electric charge pump module 330, and the intermediate node E place that the emitter of the first triode Q1 is connected with the emitter of the second triode Q2 is as an output of this line driver.Under normal circumstances, the output of main body module 310 is also in series with one end of the first resistance R1 simultaneously, and the first resistance R1 can realize impedance matching function, suppresses the reflected signal of load end.Wherein, the first switching tube Q1 and second switch pipe Q2 can be the output switch pipe in Class H line driver.

First electric charge pump module 320 comprises the first diode D1, and the positive pole of the first diode D1 is connected with positive supply VS+, and the negative pole of the first diode D2 is connected with the collector electrode of the first triode Q1.

Second electric charge pump module 330 comprises the second diode D2, and the negative pole of the second diode D2 is connected with negative supply VS-, and the positive pole of the second diode D2 is connected with the collector electrode of the second triode Q2.

Signal acquisition module 340 is for the output signal of acquisition stream through the output of main body module 310.Specifically, the magnitude of voltage at the intermediate node E place that the emitter that signal acquisition module 340 can gather the first triode Q1 is connected with the emitter of the second triode Q2 or performance number are as the signal value outputed signal.Or signal acquisition module 340 also can gather the magnitude of voltage at the other end F place of the first resistance or the performance number signal value as output signal.It should be noted that, because the output signal flowing through the output of main body module 310 mainly flows to the output of main body module 310 by external circuit, for this reason, when external circuit is different, the acquisition mode of output signal also can have multiple, so the acquisition mode of signal acquisition module 340 also has multiple, concrete restriction is not done to this herein.

Signal judge module 350 judges that whether the signal value of the output signal that signal acquisition module 340 gathers is higher than the first predetermined threshold, or lower than the second predetermined threshold.Specifically, signal judge module 350 can comprise attenuation units 352, reference source generation unit 354 and signal comparing unit 356.

Attenuation units 352 decays according to predetermined ratio for the output signal gathered signal acquisition module 340, to obtain the output signal after decaying.A kind of implementation of attenuation units 352 can shown in reference diagram 4, and attenuation units 352 comprises the identical and resistance of series connection mutually of four resistance values: the first damping resistance R11, the second damping resistance R12, the 3rd damping resistance R13 and the 4th damping resistance R14.Wherein, first damping resistance R11 is also connected with positive supply VS+, 4th damping resistance R14 is also connected with negative supply VS-, and the intermediate node that the second damping resistance R12 and the 3rd damping resistance R13 connect can be connected with the output of signal acquisition module 340, to receive output signal.Now, the first damping resistance R11 intermediate node of connecting with the second damping resistance R12 can the first pad value of output signal output; The intermediate node that 3rd damping resistance R13 connects with the 4th damping resistance R14 can the second pad value of output signal output.

Reference source generation unit 354 is for generating the reference signal of sign first predetermined threshold Vref1 and the second predetermined threshold Vref2, under normal circumstances, first predetermined threshold Vref1 is greater than the second predetermined threshold Vref2, and the first predetermined threshold Vref1 and the second predetermined threshold Vref2 can think to judge that output signal is the need of the threshold value of releasing.Reference source generation unit 354 can realize based on current source or voltage source circuit.

The reference signal that signal comparing unit 356 generates for the output signal after attenuation units 352 being decayed and reference source generation unit 354 compares, to judge that whether the signal value outputed signal is higher than the first predetermined threshold Vref1, or lower than the second predetermined threshold Vref2, the signal value wherein outputed signal can be magnitude of voltage or performance number.If the signal value of output signal is magnitude of voltage, signal comparing unit 356 can realize based on voltage comparator circuit.Specifically, the first pad value of the output signal that attenuation units 352 can export by signal comparing unit 356 compares with the first predetermined threshold Vref1, to judge that whether the signal value outputed signal is higher than the first predetermined threshold Vref1.Second pad value of the output signal that attenuation units 352 can export by signal comparing unit 356 compares with the second predetermined threshold Vref2, to judge that whether the signal value outputed signal is lower than the second predetermined threshold Vref2.

Control signal generation module 360 can be simple logic circuit or microprocessor.On the one hand, control signal generation module 360 for determine output signal at signal judge module 350 signal value higher than the first predetermined threshold Vref1 time, produce the first control signal making second switch pipe Q2 conducting.Now, output signal the negative supply VS-that released to by the second diode D2 in second switch pipe Q2 and the second electric charge pump module 330.

When the signal value that control signal generation module 360 also can determine output signal at signal judge module 350 is lower than the second predetermined threshold Vref2, produce the second control signal making the first switching tube Q1 conducting.Now, output signal the positive supply VS+ that released to by the first diode D1 in the first switching tube Q1 and the first electric charge pump module 320.

When the first switching tube Q1 and second switch pipe Q2 is transistor, because the operating state of transistor is divided into: cut-off state, magnifying state and saturation condition, control signal generation module 360 can carry out more careful adjustment.

Such as, under initial condition, first switching tube Q1 and second switch pipe Q2 all works in cut-off state, now, if signal acquisition module 340 collects the output signal of the output flowing to line driver from external circuit, and when the signal value that signal judge module 350 determines this output signal is higher than the first predetermined threshold Vref1, control signal generation module 360 can produce the first control signal making the first switching tube Q1 and second switch pipe Q2 all work in magnifying state.Now, the negative supply VS-that can be released to by the second diode D2 in second switch pipe Q2 and the second electric charge pump module 330 is outputed signal.If after a bit of scheduled duration of releasing, when the signal value that signal judge module 350 determines this output signal is still higher than the first predetermined threshold Vref1, control signal generation module 360 can produce and the first switching tube Q1 be ended and second switch pipe Q2 works in the first control signal of saturation condition.Now, second switch pipe Q2 works in saturation condition, can have stronger relieving capacity, and output signal can be made to release rapidly negative supply VS-.

In like manner, under initial condition, first switching tube Q1 and second switch pipe Q2 all works in cut-off state, now, if signal acquisition module 340 collects the output signal of the output flowing to line driver from external circuit, and when the signal value that signal judge module 350 determines this output signal is lower than the second predetermined threshold Vref2, control signal generation module 360 can produce the second control signal making the first switching tube Q1 and second switch pipe Q2 all work in magnifying state.Now, output signal can be released positive supply VS+ by the first diode D1 in the first switching tube Q1 and the first electric charge pump module 320.If after a bit of scheduled duration of releasing, when the signal value that signal judge module 350 determines this output signal is still lower than the second predetermined threshold Vref2, control signal generation module 360 can produce and make the first switching tube Q1 work in saturation condition and second switch pipe Q2 first control signal of ending.Now, the first switching tube Q1 works in saturation condition, can have stronger relieving capacity, and output signal can be made to release rapidly positive supply VS+.

In sum, the line driver that the embodiment of the present invention two provides, by increasing signal acquisition module, signal judge module and control signal generation module, can utilize the output switch pipe in line driver to be used as the leakage path of the output signal of outside line.Utilize the output switch pipe in line driver inherently to have the feature of stronger power bearing ability, solve the problem that the protective capacities of TVS pipe to output signal is poor, reach the beneficial effect of the protective capacities effectively strengthening line driver.Simultaneously, when the first switching tube Q1 and second switch pipe Q2 is transistor, the control signal generation module 360 that the embodiment of the present invention two provides can produce the control signal making the first switching tube Q1 or second switch pipe Q2 work in different conditions, to produce different relieving capacities.

Embodiment three

Please refer to Fig. 5, it illustrates the circuit diagram of the line driver that the embodiment of the present invention three provides.The present embodiment three also may be used for the protection to Class H line driver.With above-described embodiment unlike, this Class H line driver can comprise the output of two difference form.This line driver comprises the first main body module 510, second main body module 520, first electric charge pump module 530, second electric charge pump module 540, first signal acquisition module 550, secondary signal acquisition module 560, first signal judge module 570, secondary signal judge module 580 and control signal generation module 590.

First main body module 510 comprises the first switching tube Q1 and the second switch pipe Q2 (other element does not specifically illustrate) of series connection.When the first switching tube Q1 and second switch pipe Q2 is triode, the emitter of the first triode Q1 is connected with the emitter of the second triode Q2, the collector electrode of the first triode Q1 is connected with positive supply VS+ by the first electric charge pump module 530, the collector electrode of the second triode Q2 is connected with negative supply VS-by the second electric charge pump module 540, and the voltage at the node E place that the emitter of the first triode Q1 is connected with the emitter of the second triode Q2 is as a difference output end of this line driver.Under normal circumstances, the output of the first main body module 510 is also in series with the first resistance R1 simultaneously, and the first resistance R1 can realize impedance matching function, suppresses the reflected signal of load end.Wherein, the first switching tube Q1 and second switch pipe Q2 can be the output switch pipe in Class H line driver.

Second main body module 520 comprises the 3rd switching tube Q3 and the 4th switching tube Q4 (other element does not specifically illustrate) of series connection.When the 3rd switching tube Q3 and the 4th switching tube Q4 is triode, the emitter of the 3rd triode Q3 is connected with the emitter of the 4th triode Q4, the collector electrode of the 3rd triode Q3 is connected with positive supply VS+ by the first electric charge pump module 530, the collector electrode of the 4th triode Q4 is connected with negative supply VS-by the second electric charge pump module 540, and one end of the second resistance R2 is connected with the emitter of the 4th triode Q4 with the emitter of the 3rd triode Q3, the voltage at the node F place that the emitter of the 3rd triode Q3 is connected with the emitter of the 4th triode Q4 is as another difference output end of this line driver.Under normal circumstances, the output of the second main body module 520 is also in series with the second resistance R2 simultaneously, and the second resistance R2 can realize impedance matching function, suppresses the reflected signal of load end.Wherein, the 3rd switching tube Q3 and the 4th switching tube Q4 also can be the output switch pipe in Class H line driver.

Two difference output ends of this line driver can also be connected with external circuit 55, and external circuit 55 can include the device such as transformer circuit and electric capacity C1.

First electric charge pump module 530 comprises the first diode D1, and the positive pole of the first diode D1 is connected with positive supply VS+, and the negative pole of the first diode D2 is connected with the collector electrode of the 3rd triode Q3 with the collector electrode of the first triode Q1.

Second electric charge pump module 540 comprises the second diode D2, and the negative pole of the second diode D2 is connected with negative supply VS-, and the positive pole of the second diode D2 is connected with the collector electrode of the 4th triode Q4 with the collector electrode of the second triode Q2.

First signal acquisition module 550 is for the output signal of acquisition stream through the output of the first main body module 510.Specifically, the first signal acquisition module 550 may be used for gathering the first switching tube Q1 of series connection and the magnitude of voltage at intermediate node E1 place of second switch pipe Q2 or performance number as the signal value outputed signal.First signal acquisition module 550 also may be used for the magnitude of voltage at the other end F1 place of collection first resistance R1 or the performance number signal value as output signal.

Secondary signal acquisition module 560 is for the output signal of acquisition stream through the output of the second main body module 520.Specifically, secondary signal acquisition module 560 may be used for gathering the 3rd switching tube Q3 of series connection and the magnitude of voltage of intermediate node E1 of the 4th switching tube Q4 or the performance number signal value as output signal.Secondary signal acquisition module 560 also may be used for the magnitude of voltage at the other end F2 place of collection second resistance R2 or the performance number signal value as output signal.

It should be noted that, output signal due to the output of current through line driver mainly flows to the output of line driver by external circuit 55, for this reason, when external circuit 55 is different, the acquisition mode of output signal also can have multiple, so the acquisition mode of the first signal acquisition module 550 and secondary signal acquisition module 560 also has multiple, concrete restriction is not done to this herein.Such as, the first signal acquisition module 550 and secondary signal acquisition module 560 can also gather the signal value of voltage as output signal at electric capacity C1 two ends.

First signal judge module 570 for the signal value of output signal that judges the first signal acquisition module 550 and gather whether higher than the first predetermined threshold, or lower than the second predetermined threshold.First signal judge module 570 specifically can comprise the first reference source generation unit 572 and the first signal comparing unit 574, as shown in Figure 6.Wherein, the first reference source generation unit 572 is for generating the reference signal of sign first predetermined threshold Vref1 and the second predetermined threshold Vref2.The reference signal that first signal comparing unit 574 generates for the output signal that the first signal acquisition module 550 gathered and the first reference source generation unit 572 compares, to judge that whether the signal value outputed signal is higher than the first predetermined threshold Vref1, or lower than the second predetermined threshold Vref2.More preferably, the first signal judge module 570 can also comprise the first attenuation units 576, as shown in Figure 7.First attenuation units 576 decays according to predetermined ratio for the output signal the first signal acquisition module 550 gathered, to obtain the output signal after decaying.Now, the reference signal that first signal comparing unit 574 generates specifically for the output signal after the first attenuation units 576 being decayed and the first reference source generation unit 572 compares, to judge that whether the signal value outputed signal is higher than the first predetermined threshold Vref1, or lower than the second predetermined threshold Vref2.Details is realized for the first attenuation units 576, can the description part of attenuation units in reference example two.

Secondary signal judge module 580 for judging that whether the signal value of the output signal that secondary signal acquisition module 560 gathers is higher than the 3rd predetermined threshold, or lower than the 4th predetermined threshold.Secondary signal judge module 580 specifically can comprise the second reference source generation unit 582 and secondary signal comparing unit 584, as shown in Figure 8.Wherein, the second reference source generation unit 582 is for generating the reference signal of sign the 3rd predetermined threshold Vref3 and the 4th predetermined threshold Vref4.The reference signal that secondary signal comparing unit 584 generates for the output signal that gathered by secondary signal acquisition module 560 and the second reference source generation unit 582 compares, to judge that whether the signal value outputed signal is higher than the 3rd predetermined threshold Vref3, or lower than the 4th predetermined threshold Vref4.More preferably, secondary signal judge module can also comprise the second attenuation units 586, as shown in Figure 9.Wherein, the second attenuation units 586 decays according to predetermined ratio for the output signal gathered by secondary signal acquisition module 560, to obtain the output signal after decaying.Secondary signal comparing unit 584 compares specifically for the output signal after the second attenuation units 586 being decayed and reference signal, to judge that whether the signal value outputed signal is higher than the 3rd predetermined threshold Vref3, or lower than the 4th predetermined threshold Vref4.Details is realized for the second attenuation units 586, can the description part of attenuation units in reference example two.

When the first signal judge module 570 determines the signal value of output signal that the first signal acquisition module 550 gathers higher than the first predetermined threshold Vref1, or when secondary signal judge module 580 determines the signal value of output signal that secondary signal acquisition module 560 gathers lower than the 4th predetermined threshold Vref4, control signal generation module 590 is for generation of the 3rd control signal making the Q2 conducting of second switch pipe and the 3rd switching tube Q3 conducting.

When the first signal judge module 570 determines the signal value of output signal that the first signal acquisition module 550 gathers lower than the second predetermined threshold Vref2, or when secondary signal judge module 580 determines the signal value of output signal that secondary signal acquisition module 560 gathers higher than the 3rd predetermined threshold Vref3, control signal generation module 590 is also for generation of the 4th control signal making the first switching tube Q1 conducting and the 4th switching tube Q4 conducting.

When the first switching tube Q1, second switch pipe Q2, the 3rd switching tube Q3 and the 4th switching tube Q4 are transistor, because the operating state of transistor is divided into: cut-off state, magnifying state and saturation condition, control signal generation module 590 can carry out more careful adjustment.

Such as, under initial condition, each switching tube all works in cut-off state, when the first signal judge module 570 judges the signal value of the output signal that the first signal acquisition module 550 gathers higher than the first predetermined threshold Vref1, or when secondary signal judge module 580 judges the signal value of the output signal that secondary signal acquisition module 560 gathers lower than the 4th predetermined threshold Vref4, control signal generation module 590 can produce the 3rd control signal making the first switching tube Q1, second switch pipe Q2, the 3rd switching tube Q3 and the 4th switching tube Q4 all work in magnifying state.Now, the output signal illustrating A line can be released to by the second diode D2 in second switch pipe Q2 and the second electric charge pump module 530 negative supply VS-; Meanwhile, the output signal illustrating B line also can be released to by the first diode D1 in the 3rd switching tube Q3 and the first charge pump 520 positive supply VS+.If after a bit of scheduled duration of releasing, when first signal judge module 570 still determines the signal value of output signal that the first signal acquisition module 550 gathers higher than the first predetermined threshold Vref1, or secondary signal judge module 580 still determines the signal value of the output signal that secondary signal acquisition module 560 gathers lower than the 4th predetermined threshold Vref4, control signal generation module 590 can produce and the first switching tube Q1 is ended, second switch pipe Q2 works in saturation condition, 3rd switching tube Q3 works in the 3rd control signal of saturation condition and the 4th switching tube Q4 cut-off.Now, second switch pipe Q2 and the 3rd switching tube Q3 works in saturation condition, can have stronger relieving capacity, and output signal can be made to release more rapidly.

In like manner, under initial condition, each switching tube all works in cut-off state, when the first signal judge module 570 determines the signal value of output signal that the first signal acquisition module 530 gathers lower than the second predetermined threshold Vref2, or when secondary signal judge module 580 determines the signal value of output signal that secondary signal acquisition module 540 gathers higher than the 3rd predetermined threshold Vref3, control signal generation module produces and makes the first switching tube Q1, second switch pipe Q2, the 3rd switching tube Q3 and the 4th switching tube Q4 all work in the 4th control signal of magnifying state.Now, the output signal illustrating A line can be released to by the first diode D1 in the first switching tube Q2 and the first electric charge pump module 520 positive supply VS+; Meanwhile, the output signal illustrating B line also can be released to by the second diode D2 in the 4th switching tube Q4 and the second charge pump 530 negative supply VS-.If after a bit of scheduled duration of releasing, when first signal judge module 570 still determines the signal value of output signal that the first signal acquisition module 550 gathers lower than the second predetermined threshold Vref2, or secondary signal judge module 580 still determines the signal value of the output signal that secondary signal acquisition module 560 gathers higher than the 3rd predetermined threshold Vref3, control signal generation module 590 can produce and make the first switching tube Q1 work in saturation condition, second switch pipe Q2 ends, 3rd switching tube Q3 cut-off and the 4th switching tube Q4 work in the 4th control signal of saturation condition.Now, the first switching tube Q1 and the 4th switching tube Q4 works in saturation condition, can have stronger relieving capacity, and output signal can be made to release more rapidly.

In sum, the line driver that the embodiment of the present invention three provides, by increasing signal acquisition module, signal judge module and control signal generation module, can utilize the output switch pipe in line driver to be used as the leakage path of the output signal of outside line.Utilize the output switch pipe in line driver inherently to have the feature of stronger power bearing ability, solve the problem that the protective capacities of TVS pipe to output signal is poor, reach the beneficial effect of the protective capacities effectively strengthening line driver.Meanwhile, when each switching tube is transistor, the control signal generation module that the embodiment of the present invention three provides can produce the control signal making each switching tube work in different conditions, to produce different relieving capacities.

It should be noted that, under normal circumstances, the first predetermined threshold equals the 3rd predetermined threshold, and the second predetermined threshold equals the 4th threshold value.Now, above-mentioned first signal acquisition module and secondary signal acquisition module can realize becoming a module, and the first signal judge module and secondary signal judge module also can realize becoming a module.When the first signal judge module and secondary signal judge module realize becoming a signal judge module, this signal judge module also can by judging that whether exceeding predetermined threshold between the differential signal that two difference output ends export is equal to the deterministic process realizing output signal.

Embodiment four

Please refer to Figure 10, it illustrates the method flow diagram of the means of defence of the line driver that the embodiment of the present invention four provides.The means of defence of this line driver may be used in the protection of ClassAB or ClassH line driver.ClassAB or ClassH line driver all comprises the first switching tube and the second switch pipe of series connection, and the intermediate node of the first switching tube and second switch pipe is the output of ClassAB or ClassH line driver.The means of defence of this line driver can comprise:

Step 102, the output signal of the output of acquisition stream via line driver;

Step 104, judges that whether the signal value outputed signal is higher than the first predetermined threshold, or lower than the second predetermined threshold; If so, then step 106 is entered; If not, then step 108 is entered;

Step 106, if when the signal value of output signal is higher than the first predetermined threshold, produces the first control signal controlling the conducting of second switch pipe;

Specifically, when the first switching tube and second switch pipe are transistor, because the operating state of transistor is divided into: cut-off state, magnifying state and saturation condition.So this step can include 3 kinds of implementations:

The first, produce and make the first switching tube and second switch Guan Jun works in the first control signal of magnifying state.This implementation is applicable to the first switching tube and second switch pipe is initially all in the sight of cut-off state, can be issued to certain relieving capacity in speed quickly.

The second, produce and make the first switching tube cut-off and second switch pipe works in the first control signal of saturation condition.This implementation is applicable to the first switching tube and second switch pipe is initially in the sight of operating state, can be issued to stronger relieving capacity in speed quickly.

3rd, first produce and make the first switching tube and second switch pipe all works in the first control signal of magnifying state;

Then whether the signal value of output signal is rejudged still higher than the first predetermined threshold;

If the signal value of output signal is still higher than the first predetermined threshold, then produces and make the first switching tube cut-off and second switch pipe works in the first control signal of saturation condition.

This implementation is applicable to the first switching tube and second switch pipe is initially all in the sight of cut-off state, first make the first switching tube and second switch pipe all works in magnifying state, first can be issued to certain relieving capacity in speed quickly, then continue real-time judge or judge that the signal value of output signal is still higher than the first predetermined threshold every a period of time, if, then make first switching tube cut-off and second switch pipe works in saturation condition, relieving capacity more strongly can be obtained, thus output signal is released rapidly.

Step 108, if when the signal value of output signal is lower than the second predetermined threshold, produces the second control signal of control first switching tube conducting.

The first, produce and make the first switching tube and second switch pipe all works in the second control signal of magnifying state.This implementation is applicable to the first switching tube and second switch pipe is initially all in the sight of cut-off state, can be issued to certain relieving capacity in speed quickly.

The second, produce and make the first switching tube work in saturation condition and the second control signal of second switch pipe cut-off.This implementation is applicable to the first switching tube and second switch pipe is initially in the sight of operating state, can be issued to stronger relieving capacity in speed quickly.

3rd, first produce and make the first switching tube and second switch pipe all works in the second control signal of magnifying state;

Then, whether the signal value of output signal is rejudged still lower than the second predetermined threshold;

If the signal value of output signal is still lower than the second predetermined threshold, then produces and make the first switching tube work in saturation condition and the second control signal of second switch pipe cut-off.

This implementation is applicable to the first switching tube and second switch pipe is initially all in the sight of cut-off state, first make the first switching tube and second switch pipe all works in magnifying state, first can be issued to certain relieving capacity in speed quickly, then continue real-time judge or judge that the signal value of output signal is still higher than the first predetermined threshold every a period of time, if, the first switching tube is then made to work in saturation condition and the cut-off of second switch pipe, relieving capacity more strongly can be obtained, thus output signal is released rapidly.

In sum, the leakage path of means of defence by utilizing the output switch pipe in line driver to be used as the output signal of outside line of line driver that provide of the embodiment of the present invention four.Utilize the output switch pipe in line driver inherently to have the feature of stronger power bearing ability, solve the problem that the protective capacities of TVS pipe to output signal is poor, reach the beneficial effect of the protective capacities effectively strengthening line driver.

One of ordinary skill in the art will appreciate that all or part of step realizing above-described embodiment can have been come by hardware, the hardware that also can carry out instruction relevant by program completes, described program can be stored in a kind of computer-readable recording medium, the above-mentioned storage medium mentioned can be read-only memory, disk or CD etc.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1. a line driver, is characterized in that, comprising:

Main body module, comprise the first switching tube and the second switch pipe of series connection, described first switching tube is connected with positive supply, and described second switch pipe is also connected with negative supply, and the first switching tube of described series connection and the intermediate node of second switch pipe are as the output of described main body module;

Signal judge module, for judging that whether the signal value of described output signal is higher than the first predetermined threshold, or lower than the second predetermined threshold;

Control signal generation module, for determine described output signal at described signal judge module signal value higher than described first predetermined threshold time, produce the first control signal and make the conducting of described second switch pipe form the leakage path of described output signal; Or when the signal value that described signal judge module determines described output signal is lower than described second predetermined threshold, produces the second control signal and make described first switching tube conducting form the leakage path of described output signal.

2. line driver according to claim 1, is characterized in that,

Described first switching tube is connected with described positive supply by the first electric charge pump module, described first electric charge pump module comprises the first diode, the positive pole of described first diode is connected with described positive supply, and the negative pole of described first diode is connected with described first switching tube;

Described second switch pipe is connected with described negative supply by the second electric charge pump module, described second electric charge pump module comprises the second diode, the negative pole of described second diode is connected with described negative supply, and the positive pole of described second diode is connected with described second switch pipe.

3. line driver according to claim 1 and 2, is characterized in that, the output of described main body module is also connected with one end of the first resistance;

Described signal acquisition module, specifically for gathering the magnitude of voltage of the other end of described first resistance or the performance number signal value as described output signal.

4. line driver according to claim 1 and 2, is characterized in that, described signal judge module comprises:

Reference source generation unit and signal comparing unit;

Described reference source generation unit, for generating the reference signal characterizing described first predetermined threshold and described second predetermined threshold;

Described signal comparing unit, for described output signal and described reference signal being compared, to judge that whether the signal value of described output signal is higher than described first predetermined threshold, or lower than described second predetermined threshold.

5. line driver according to claim 4, is characterized in that, described signal judge module also comprises:

Attenuation units;

Described attenuation units, decays according to predetermined ratio for the output signal described signal acquisition module gathered, to obtain the output signal after decaying;

Described signal comparing unit, specifically for the output signal after described decay and described reference signal being compared, to judge that whether the signal value of described output signal is higher than described first predetermined threshold, or lower than described second predetermined threshold.

6. line driver according to claim 1 and 2, is characterized in that, described first switching tube and described second switch pipe are transistor;

When the signal value that described signal judge module determines described output signal is higher than described first predetermined threshold, described control signal generation module is for generation of making described first switching tube and described second switch Guan Jun works in the first control signal of magnifying state;

Or, when the signal value that described signal judge module determines described output signal is lower than described second predetermined threshold, described control signal generation module is for generation of making described first switching tube and described second switch Guan Jun works in the second control signal of magnifying state.

7. line driver according to claim 1 and 2, is characterized in that, described first switching tube and second switch pipe are transistor;

When the signal value that described signal judge module determines described output signal is higher than described first predetermined threshold, described control signal generation module is for generation of making described first switching tube cut-off and described second switch pipe works in the first control signal of saturation condition;

Or, when the signal value that described signal judge module determines described output signal is lower than described second predetermined threshold, described control signal generation module is for generation of making described first switching tube work in saturation condition and the second control signal of described second switch pipe cut-off.

8. a line driver, is characterized in that, comprising:

First main body module, comprises the first switching tube and the second switch pipe of series connection, and the first switching tube of described series connection and the intermediate node of second switch pipe are as the output of described first main body module;

First signal judge module, for judging that whether the signal value of the output signal that described first signal acquisition module gathers is higher than the first predetermined threshold, or lower than the second predetermined threshold;

Secondary signal judge module, for judging that whether the signal value of the output signal that described secondary signal acquisition module gathers is higher than the 3rd predetermined threshold, or lower than the 4th predetermined threshold;

Control signal generation module, during for determining the signal value of output signal that described first signal acquisition module gathers at described first signal judge module higher than described first predetermined threshold, or when described secondary signal judge module determines the signal value of output signal that described secondary signal acquisition module gathers lower than described 4th predetermined threshold, produce the 3rd control signal and make the conducting of described second switch pipe and described 3rd switching tube conducting form the leakage path of described output signal;

When described first signal judge module determines the signal value of output signal that described first signal acquisition module gathers lower than described second predetermined threshold, or when described secondary signal judge module determines the signal value of output signal that described secondary signal acquisition module gathers higher than described 3rd predetermined threshold, produce the 4th control signal and make described first switching tube conducting and described 4th switching tube conducting form the leakage path of described output signal;

Wherein, described first switching tube is also connected with positive supply with described 3rd switching tube, and described second switch pipe is also connected with negative supply with the 4th switching tube.

9. line driver according to claim 8, it is characterized in that, described first switching tube is connected with described positive supply by the first electric charge pump module with described 3rd switching tube, described first electric charge pump module comprises the first diode, the positive pole of described first diode is connected with described positive supply, and the negative pole of described first diode is connected with described 3rd switching tube with described first switching tube;

Described second switch pipe is connected with described negative supply by the second electric charge pump module with the 4th switching tube, described second electric charge pump module comprises the second diode, the negative pole of described second diode is connected with described negative supply, and the positive pole of described second diode is connected with the 4th switching tube with described second switch pipe.

10. line driver according to claim 8, is characterized in that, described first predetermined threshold equals the 3rd predetermined threshold, and described second predetermined threshold equals the 4th predetermined threshold.

Line driver described in 11. according to Claim 8 to 10 are arbitrary, it is characterized in that, the output of described first main body module is also connected with one end of the first resistance;

Described first signal acquisition module, specifically for gathering the magnitude of voltage of the other end of described first resistance or the performance number signal value as described output signal;

And/or the output of described second main body module is also connected with one end of the second resistance;

Described secondary signal acquisition module, specifically for gathering the magnitude of voltage of the other end of described second resistance or the performance number signal value as described output signal.

Line driver described in 12. according to Claim 8 to 10 are arbitrary, it is characterized in that, described first signal judge module, specifically comprises:

First reference source generation unit and the first signal comparing unit;

Described first reference source generation unit, for generating the reference signal characterizing described first predetermined threshold and described second predetermined threshold;

Described first signal comparing unit, for described output signal and described reference signal being compared, to judge that whether the signal value of described output signal is higher than described first predetermined threshold, or lower than described second predetermined threshold;

With, described secondary signal judge module, specifically comprises:

Second reference source generation unit and secondary signal comparing unit;

Described second reference source generation unit, for generating the reference signal characterizing described 3rd predetermined threshold and described 4th predetermined threshold;

Described secondary signal comparing unit, for described output signal and described reference signal being compared, to judge that whether the signal value of described output signal is higher than described 3rd predetermined threshold, or lower than described 4th predetermined threshold.

13. line drivers according to claim 12, is characterized in that, described first signal judge module also comprises:

First attenuation units;

Described first attenuation units, for the output signal of described first signal acquisition module collection being decayed according to predetermined ratio, to obtain the output signal after decaying;

Described first signal comparing unit, specifically for the output signal after described first attenuation units decay and described reference signal are compared, to judge that whether the signal value of described output signal is higher than described first predetermined threshold, or lower than described second predetermined threshold;

With, described secondary signal judge module also comprises:

Second attenuation units;

Described second attenuation units, for the output signal of described secondary signal acquisition module collection being decayed according to predetermined ratio, to obtain the output signal after decaying;

Described secondary signal comparing unit, specifically for the output signal after described second attenuation units decay and described reference signal are compared, to judge that whether the signal value of described output signal is higher than described 3rd predetermined threshold, or lower than described 4th predetermined threshold.

Line driver described in 14. according to Claim 8 to 10 are arbitrary, it is characterized in that, described first switching tube, second switch pipe, the 3rd switching tube and the 4th switching tube are transistor;

When described first signal judge module judges the signal value of the output signal that described first signal acquisition module gathers higher than described first predetermined threshold, or when described secondary signal judge module judges the signal value of the output signal that described secondary signal acquisition module gathers lower than described 4th predetermined threshold, described control signal generation module is for generation of the 3rd control signal making described first switching tube, described second switch pipe, described 3rd switching tube and described 4th switching tube all work in magnifying state;

When described first signal judge module judges the signal value of the output signal that described first signal acquisition module gathers lower than described second predetermined threshold, or when described secondary signal judge module judges the signal value of the output signal that described secondary signal acquisition module gathers higher than described 3rd predetermined threshold, described control signal generation module is for generation of the 4th control signal making described first switching tube, described second switch pipe, described 3rd switching tube and described 4th switching tube all work in magnifying state.

Line driver described in 15. according to Claim 8 to 10 are arbitrary, it is characterized in that, described first switching tube, second switch pipe, the 3rd switching tube and the 4th switching tube are transistor;

When described first signal judge module determines the signal value of output signal that described first signal acquisition module gathers higher than described first predetermined threshold, or when described secondary signal judge module determines the signal value of output signal that described secondary signal acquisition module gathers lower than described 4th predetermined threshold, described control signal generation module for generation of controlling described first switching tube cut-off, described second switch pipe works in saturation condition, described 3rd switching tube works in saturation condition and the 3rd control signal of described 4th switching tube cut-off;

When described first signal judge module determines the signal value of output signal that described first signal acquisition module gathers lower than described second predetermined threshold, or when described secondary signal judge module determines the signal value of output signal that described secondary signal acquisition module gathers higher than described 3rd predetermined threshold, described control signal generation module is for generation of make described first switching tube work in the 4th control signal that saturation condition, the cut-off of described second switch pipe, described 3rd switching tube cut-off and described 4th switching tube work in saturation condition.

The means of defence of 16. 1 kinds of line drivers, for in the line driver of the first switching tube and second switch pipe that comprise series connection, the intermediate node of described first switching tube and described second switch pipe is the output of described line driver, it is characterized in that, described method comprises:

Gather the output signal of the output of described line driver;

Judge that whether the signal value of described output signal is higher than the first predetermined threshold, or lower than the second predetermined threshold;

If when the signal value of described output signal is higher than described first predetermined threshold, produces the first control signal and the conducting of described second switch pipe is released described output signal;

If when the signal value of described output signal is lower than described second predetermined threshold, produces the second control signal and described first switching tube conducting is released described output signal.

The means of defence of 17. line drivers according to claim 16, is characterized in that, when described first switching tube and described second switch pipe are transistor, described generation makes the first control signal of described second switch pipe conducting, specifically comprises:

Produce and make described first switching tube and described second switch Guan Jun works in the first control signal of magnifying state;

Or, produce and make described first switching tube cut-off and described second switch pipe works in the first control signal of saturation condition.

The means of defence of 18. line drivers according to claim 16, is characterized in that, when described first switching tube and described second switch pipe are transistor, described generation makes the first control signal of described second switch pipe conducting, specifically comprises:

After described generation makes described first switching tube and described second switch Guan Jun works in the first control signal of magnifying state, described method also comprises:

Whether rejudge the signal value of described output signal still higher than described first predetermined threshold;

If the signal value of described output signal is still higher than described first predetermined threshold, then produces and make described first switching tube cut-off and described second switch pipe works in the first control signal of saturation condition.

The means of defence of 19. line drivers according to claim 16, is characterized in that, when described first switching tube and described second switch pipe are transistor, described generation makes the second control signal of described first switching tube conducting, specifically comprises:

Produce and make described first switching tube and described second switch Guan Jun works in the second control signal of magnifying state;

Or, produce and make described first switching tube work in saturation condition and the second control signal of described second switch pipe cut-off.

The means of defence of 20. line drivers according to claim 16, is characterized in that, when described first switching tube and described second switch pipe are transistor, described generation makes the second control signal of described first switching tube conducting, specifically comprises:

After described generation makes described first switching tube and described second switch Guan Jun works in the second control signal of magnifying state, described method also comprises:

Whether rejudge the signal value of described output signal still lower than described second predetermined threshold;

If the signal value of described output signal is still lower than described second predetermined threshold, then produces and make described first switching tube work in saturation condition and the second control signal of described second switch pipe cut-off.