CN104469347B - The testing circuit of video transmission cable and video frequency output chip - Google Patents
The testing circuit of video transmission cable and video frequency output chip Download PDFInfo
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- CN104469347B CN104469347B CN201410746671.2A CN201410746671A CN104469347B CN 104469347 B CN104469347 B CN 104469347B CN 201410746671 A CN201410746671 A CN 201410746671A CN 104469347 B CN104469347 B CN 104469347B
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Abstract
The invention discloses testing circuit and the video frequency output chip of a kind of video transmission cable.Wherein, the testing circuit of video transmission cable includes: DC source；First switches set, including the first switch and second switch；First resistance, the first end is connected with DC source, and the second end is connected to detect mouth by the first switch；Second resistance and the 3rd resistance；Second switch group, including the 3rd switch, the first end of the 3rd switch is for connecting the application processor of mobile device, and the second end of the 3rd switch is connected to primary nodal point；And first comparator, first input end is connected to primary nodal point, and the second input is connected to secondary nodal point.By the present invention, solve the type of cable inaccurate problem of detection to transmission of video in prior art, and then reached to improve the effect of video transmission cable detection degree of accuracy.
Description
Technical field
The present invention relates to electronic circuit field, in particular to testing circuit and the video of a kind of video transmission cable
Pio chip.
Background technology
Slimport is the digital mobile high-definition interface standard of a kind of compatible MyDP standard.MyDP full name is Mobility
DisplayPort, is that (Video Electronics Standards Association is called for short by VESA
VESA) releasing in 2011, the mobile device using this standard to make can pass through Micro USB interface, exports 1080P
HD video, high quality audio even 3D stereoscopic image is on corresponding display device.Slimport and MyDP
Completely compatible, complete same function with MyDP, will video in mobile device (such as mobile phone, flat board etc.),
By Micro USB interface and slimport cable, in output to big display device (such as TV, display etc.).
When a cable inserts the interface of mobile device, first mobile device must identify the type inserting cable, so
Rear just can making operates accordingly.Fig. 1 shows a kind of testing circuit detecting type of cable, such as Fig. 1
Shown in, AP (application processor is called for short AP) is the application processor in mobile device, and it has on one
Pull-up resistor R0 is pulled upward to power supply vdda, and the other end of pull-up resistor receives mobile device interface (connector by cabling
I.e. con in figure, is typically now Micro-USB interface) a pin on.In present applications ' the tail must be taken, this
Pipe lower limb is all the ID foot of micro-usb interface.
Generally, cable pull down resistor R1 distinguishes type of cable, say, that different cables has different drop-down
Resistance R1.The pull down resistor of the MyDP cable (or slimport cable) of MyDP definition is 620K.
When not having cable to access, the voltage (V_det in figure) of ID foot is exactly vdda.When there being cable to insert, V_det
Voltage will be determined by resistance R0 and resistance R1 dividing potential drop.Owing to the R1 of different cables is different, so connecting different
After cable, the voltage of V_det is the most different.AP is through detecting the voltage swing of V_det and detects and differentiate cable
Type.
But due to MyDP standard goes out after being, and a lot of AP is to have manufactured before MyDP standard is out,
So a lot of AP do not have the ability of detection MyDP (or slimport) cable, accordingly, it would be desirable to by means of third party
MyDP (or slimport) cable detects by detection chip, prior art provides a kind of as shown in Figure 2
Detection chip CO2,
In fig. 2, R2=R3, R4=R1.R3 and R4 dividing potential drop, obtains V_ref.As MyDP (or slimport)
When cable accesses, when namely R1 connects, the voltage of V_det will be equal with V_ref, and a det sent by comparator
Signal has MyDP (or slimport) cable to insert to AP, notice AP, can export video.
But the testing circuit provided in prior art, for detection voltage V_det, except by pull-up resistor R2's
Outside effect, also acting on by the pull-up resistor R0 in AP, due to the impact of R0, cause MyDP (or slimport)
When cable inserts, V_det and V_ref is the most unequal, the precision of impact detection.Equally, when other kinds of cable
During insertion, due to the impact of R2, the voltage V_det that AP obtains is the most no longer the dividing potential drop of R0 and R1, the most also can
Affect AP to the detection of other type cable and resolution.
For the type of cable of transmission of video is detected inaccurate problem by correlation technique, the most not yet propose effective
Solution.
Summary of the invention
Present invention is primarily targeted at testing circuit and the video frequency output chip that a kind of video transmission cable is provided, to solve
In prior art of determining, the type of cable to transmission of video detects inaccurate problem.
According to an aspect of the invention, it is provided the testing circuit of a kind of video transmission cable.
The testing circuit of the video transmission cable according to the present invention includes: DC source；First switches set, including first
Switch and second switch, wherein, described first switch and described second switch have an identical on off state, and the
The original state of one switch and described second switch is closure state；First resistance, the first end and described DC source phase
Connecting, the second end is connected to detect mouth by described first switch, and wherein, described detection mouth is used for connecting described video
Transmission cable；Second resistance and the 3rd resistance, wherein, the first end of described second resistance is connected with described DC source
Connecing, described second switch is connected between the second end of described second resistance and the first end of described 3rd resistance, described
Second end of the 3rd resistance is connected to signal ground, and the resistance of described second resistance is identical with the resistance of described first resistance,
The resistance of described 3rd resistance is preset resistive value；Second switch group, including the 3rd switch, the first of described 3rd switch
End is for connecting the application processor of mobile device, and the second end of described 3rd switch is connected to primary nodal point, wherein,
Described primary nodal point is the node between described first switch and described detection mouth, and the original state of described 3rd switch is
Off-state, described mobile device is for transmitting video by described video transmission cable；And first comparator,
One input is connected to described primary nodal point, and the second input is connected to secondary nodal point, and outfan is for described first
The input voltage of the second input of the input voltage of the first input end of comparator and described first comparator differs
In the case of, output triggers described first switch, described second switch and the triggering of described 3rd switch switching on off state
Signal.
Further, described testing circuit also includes: AUX channel, is connected to described primary nodal point, for described
In the case of mobile device is by described video transmission cable transmission video, receive return signal；Reset circuit, with institute
State AUX channel to be connected, in the case of described AUX channel does not receives described return signal, reset institute
Stating testing circuit is original state.
Further, described first switches set also includes that the 4th switch, described 4th switch and described first switch have
Identical on off state, described testing circuit also includes: the second comparator, and first input end is by described 4th switch
Being connected to described DC source, the second input is connected to described primary nodal point, and outfan is for comparing described second
The situation that the input voltage of the input voltage of the first input end of device and the second input of described second comparator differs
Under, output enables signal.
Further, described testing circuit also includes: enumerator, the outfan phase of input and described second comparator
Connect；First d type flip flop, D input is connected with the outfan of described first comparator, clock signal input terminal
Being connected with described enumerator, Q output is connected with described application processor；Second d type flip flop, D input
Connecting low level signal, clock signal input terminal is connected with described enumerator, and Q output output controls described first
The control signal of switches set on off state；And 3d flip-flop, D input connects high level signal, and clock is believed
Number input is connected with described enumerator, and Q output output controls the control letter of described second switch group on off state
Number.
Further, described reset circuit includes: ono shot pulse circuit, with described application processor and described counting
Device is all connected, and wherein, the Q output at described first d type flip flop transmits low level signal and processes to described application
In the case of device, described application processor output high level signal is to described ono shot pulse circuit, to reset in terms of described
Number device.
According to a further aspect in the invention, it is provided that a kind of video frequency output chip, this video frequency output chip includes the present invention
The testing circuit of any one video transmission cable that foregoing is provided.
In the present invention, use there is the testing circuit of video transmission cable of following structure: DC source；First opens
Pass group, including the first switch and second switch, wherein, described first switch and described second switch have identical opening
Off status, and the first switch and the original state of described second switch be closure state；First resistance, the first end with
Described DC source is connected, and the second end is connected to detect mouth by described first switch, and wherein, described detection mouth is used
In connecting described video transmission cable；Second resistance and the 3rd resistance, wherein, the first end of described second resistance and institute
Stating DC source to be connected, described second switch is connected to the second end of described second resistance and the of described 3rd resistance
Between one end, the second end of described 3rd resistance is connected to signal ground, described second resistance and resistance and described first electricity
The resistance of resistance is identical, and the resistance of described 3rd resistance is preset resistive value；Second switch group, including the 3rd switch, described
First end of the 3rd switch is for connecting the application processor of mobile device, and the second end of described 3rd switch is connected to the
One node, wherein, described primary nodal point is the node between described first switch and described detection mouth, and the described 3rd opens
The original state closed is off-state, and described mobile device is for transmitting video by described video transmission cable；And
First comparator, first input end is connected to described primary nodal point, and the second input is connected to secondary nodal point, outfan
Input voltage and the second input of described first comparator defeated for the first input end at described first comparator
Entering in the case of voltage differs, output triggers described first switch, described second switch and described 3rd switch switching
The triggering signal of on off state.By the present invention, solve in prior art the type of cable to transmission of video and detect not
Problem accurately, and then reached to improve the effect of video transmission cable detection degree of accuracy.
Accompanying drawing explanation
The accompanying drawing of the part constituting the application is used for providing a further understanding of the present invention, and the present invention's is schematic real
Execute example and illustrate for explaining the present invention, being not intended that inappropriate limitation of the present invention.In the accompanying drawings:
Fig. 1 is a kind of circuit diagram detecting video transmission cable according to correlation technique；
Fig. 2 is another circuit diagram detecting video transmission cable according to correlation technique；
Fig. 3 is the circuit diagram of the testing circuit of video transmission cable according to embodiments of the present invention；And
Fig. 4 is the circuit diagram of the testing circuit of the video transmission cable according to further embodiment of this invention.
Detailed description of the invention
In order to make those skilled in the art be more fully understood that the present invention program, below in conjunction with in the embodiment of the present invention
Accompanying drawing, is clearly and completely described the technical scheme in the embodiment of the present invention, it is clear that described embodiment
It is only the embodiment of a present invention part rather than whole embodiments.Based on the embodiment in the present invention, ability
The every other embodiment that territory those of ordinary skill is obtained under not making creative work premise, all should belong to
The scope of protection of the invention.
It should be noted that term " first " in description and claims of this specification and above-mentioned accompanying drawing, "
Two " it is etc. for distinguishing similar object, without being used for describing specific order or precedence.Should be appreciated that this
Sample use data can exchange in the appropriate case, in order to embodiments of the invention described herein can with except
Here the order beyond those illustrating or describing is implemented.Additionally, term " includes " and " having " and they
Any deformation, it is intended that cover non-exclusive comprising, such as, contain series of steps or the process of unit, side
Method, system, product or equipment are not necessarily limited to those steps or the unit clearly listed, but can include the clearest
List or for intrinsic other step of these processes, method, product or equipment or unit.
In the case of not conflicting, the embodiment in the application and the feature in embodiment can be mutually combined.Below will
Reference accompanying drawing also describes the present invention in detail in conjunction with the embodiments.
According to embodiments of the present invention, it is provided that the testing circuit of a kind of video transmission cable, below to the embodiment of the present invention
The testing circuit of the video transmission cable provided does specifically to be introduced:
Fig. 3 is the schematic diagram of the testing circuit of video transmission cable according to embodiments of the present invention, as it is shown on figure 3, should
The testing circuit CO3 of video transmission cable mainly include DC source vdda, first switch S11, second switch S12,
3rd switch S21, the first resistance R2, the second resistance R3, the 3rd resistance R4 and the first comparator B1, specifically:
DC source vdda can be the power supply that can provide 3.3V DC voltage, the first switch S11 and second switch
S12 belongs to the first switches set, and the two has identical on off state, and original state is closure state, i.e.
First switch S11 and second switch S12 has identical on off state, and the first switch S11 and second switch S12
Original state be closure state；First end of the first resistance R2 is connected with DC source vdda, the first resistance R2
The second end by first switch S11 be connected to detect mouth con, wherein, detection mouth con be used for connecting transmission of video
Cable, resistance R1 is the pull down resistor of video transmission cable；First end of the second resistance R3 and DC source vdda
Being connected, second switch S12 is connected between the second end and first end of the 3rd resistance R4 of the second resistance R3, the
Second end of three resistance R4 is connected to signal ground, and the second resistance R3 is identical with the resistance of the first resistance R2 with resistance,
The resistance of the 3rd resistance R4 is preset resistive value, is MyDP cable or slimport cable for video transmission cable
Situation, the resistance of the 3rd resistance R4 is 620K.3rd switch S21 belongs to the switch in second switch group, and the 3rd opens
The first end closing S21 is used for connecting the application processor AP of mobile device, and second end of the 3rd switch S21 is connected to
Primary nodal point, wherein, primary nodal point is the first switch S11 and the node detected between mouth con, the 3rd switch S21
Original state be off-state, mobile device for by video transmission cable transmit video, resistance R0 for application
Pull-up resistor in processor AP.The first input end of the first comparator B1 is connected to primary nodal point, the second input
Being connected to secondary nodal point, outfan compares for the input voltage and first of the first input end at the first comparator B1
In the case of the input voltage of second input of device B1 differs, output triggers the first switch S11, second switch
The triggering signal of S12 and the 3rd switch S21 switching on off state.
For the testing circuit of the video transmission cable of the embodiment of the present invention, under original state, the first switch S11 and the
Two switch S12 Guan Bis, the 3rd switch S21 disconnects.When there being video transmission cable to insert mobile device, i.e. when having
When video transmission cable accesses detection mouth, if the cable accessed is MyDP cable or slimport cable, because the
Two resistance R3 are identical with the resistance of the first resistance R2 with resistance, and the resistance of the 3rd resistance R4 is 620K, then V_ref
Necessarily equal to V_det, if the cable accessed is not MyDP cable or slimport cable, then V_ref is not equal to
V_det, therefore the testing circuit of the video transmission cable of the embodiment of the present invention can be by detection V_ref with V_det
No equal judge that video transmission cable is MyDP cable or slimport cable, due to now the 3rd switch S21
Disconnect, it is possible to get rid of the impact of resistance R0, therefore, it is possible to ensure that testing circuit is accurate to the detection of transmission of video circuit
Degree.Further, in the case of V_ref Yu V_det differs, first comparator B1 output triggering the first switch S11,
The triggering signal of second switch S12 and the 3rd switch S21 switching on off state so that the first switch S11 and second opens
Close S12 to disconnect, the 3rd switch S21 Guan Bi, to utilize application processor AP to carry out the detection of video transmission cable,
Owing to now the first switch S11 and second switch S12 is off, so application processor AP is not by first
The image of resistance R2, ensure that the testing circuit accuracy in detection to transmission of video circuit equally.Therefore, this
The testing circuit of the video transmission cable that bright embodiment is provided, solves the cable class to transmission of video in prior art
Type detects inaccurate problem, and then has reached to improve the effect of video transmission cable detection degree of accuracy.
Fig. 4 is the schematic diagram of the testing circuit of video transmission cable according to the preferred embodiment of the invention, as shown in Figure 4,
Compared with the testing circuit of the video transmission cable shown in Fig. 3, the transmission of video of the preferred embodiment shown in Fig. 4
The testing circuit of cable also includes AUX channel and reset circuit, and wherein, AUX channel is connected to primary nodal point, uses
In the case of in mobile device by video transmission cable transmission video, receive return signal；Reset circuit and AUX
Channel is connected, and in the case of AUX channel does not receives return signal, reset detection is initial shape
State.
In the testing circuit of the video transmission cable of preferred embodiment illustrated in fig. 4, the first switches set also includes
Four switch S13, wherein, the 4th switch S13 and the first switch S11 has identical on off state, transmission of video electricity
The testing circuit of cable also includes the second comparator B2, and the first input end of the second comparator B2 is by the 4th switch S13
Being connected to DC source vdda, second input of the second comparator B2 is connected to primary nodal point, the second comparator B2
Outfan in the input voltage of first input end of the second comparator B2 and second input of the second comparator B2
In the case of the input voltage of end differs, output enables signal, after the second comparator B2 output enables signal,
The testing circuit of video transmission cable proceeds by detection.
Further, the testing circuit of video transmission cable also include enumerator C1, the first d type flip flop D1, second
D type flip flop D2 and 3d flip-flop D3, wherein, the input of enumerator C1 by with door and the second comparator
The outfan of B2 is connected, and the outfan of enumerator C1 is used for providing clock signal T00, T0, T1, T2, T3
With the outfan of the D input of T4, the first d type flip flop D1 and the first comparator B1 is connected, a D triggers
The clock signal input terminal of device D1 is connected with enumerator C1, is used for receiving clock signal T0, the first d type flip flop
The Q output of D1 is by being connected to application processor AP with door, to carry Cable_det to application processor AP
Signal；The D input of the second d type flip flop D2 connects the clock letter of low level signal L, the second d type flip flop D2
Number input is connected with enumerator C1, is used for receiving clock signal T1, T3, and the Q of the second d type flip flop D2 is defeated
Go out end output and control the control signal of the first switches set on off state；The D input of 3d flip-flop D3 connects height
Level signal, the clock signal input terminal of 3d flip-flop D3 is connected with enumerator C1, is used for receiving clock
Signal T2, T4, the Q output output of 3d flip-flop D3 controls the control letter of second switch group on off state
Number.
Reset circuit in the testing circuit of video transmission cable includes ono shot pulse circuit O1 and ono shot pulse electricity
Road O2, wherein, ono shot pulse circuit O1 is all connected with application processor sum counter, ono shot pulse circuit
O2 is all connected with application processor sum counter equally, and ono shot pulse circuit O1 receives from application processor
Chip_pd_hv signal, this signal is identical with the signal being sent to switch S_aux.Ono shot pulse circuit O2 receives
Usb_plug signal, in the case of detection mouth con accesses video transmission cable, usb_plug signal is high level letter
Number, i.e. usb_plug=1, in the case of detection mouth con does not accesses video transmission cable, usb_plug signal is
Low level signal, i.e. usb_plug=0, the Q output at the first d type flip flop D1 transmits to application processor
In the case of cable_det signal is low level signal, application processor will send the high level signal of chip_pd_hv=1
To ono shot pulse circuit O1, making ono shot pulse circuit O1 one reset value of generation to reset enumerator, detection is electric
Road is recovered to original state.
The Cleaning Principle of the testing circuit of the video transmission cable that the detailed description below embodiment of the present invention is provided:
1, to MyDP cable or the detection of slimport cable:
Under original state, switch S11, switch S12 and switch S13 Guan Bi, and switch S21 and switch S22 break
Open, when there being the video transmission cable being connected to testing circuit by detecting mouth con will detect mouth con, due to cable
Pull down resistor, the voltage at detection mouth con is had to be pulled low, and time lower than 3.3-DV, the second comparator B2's
Output signal is high level, i.e. A=1, and the first enumerator C1 and the first comparator B1 starts working.First counting
Device C1 is used for timing, and the timing at the first enumerator C1 reaches time interval T0, and this time interval T0 is according to video
After the length of transmission cable sets, the output of the first comparator B1 becomes high pressure, and the first comparator B1 starts to judge
The video transmission cable accessed is slimport cable.The most then processed by cable_det signalisation application
Device AP, to notify that application processor has MyDP or slimport video transmission cable to access, subsequent applications processor
The most exportable video of AP is to video transmission cable.Chip_pd_hv signal is set to low electricity by application processor AP simultaneously
Ordinary mail number, so that switch S_aux Guan Bi, receives detection mouth con AUX channel by switch S_aux；If it is not,
Guan Bi switch S21 and switch S22, disconnects switch S11, S12 and switch S13, will detect mouth the most in sequence
Con gives application processor AP by switch S21, ID_out signal, the application processor AP of mobile device sentence
The type of the video transmission cable that disconnected detection mouth con is connected.Send usb_det signal to application processor AP simultaneously,
Having non-slimport video transmission cable to access with notice application processor, subsequent applications processor AP starts monitoring and is
Which kind of non-slimport cable, then AP does corresponding operation.
Testing circuit at video transmission cable detects that the video transmission cable that detection mouth con connects is MyDP cable
Or in the case of slimport cable, the testing circuit of video transmission cable enters Slimport pattern, mobile device is led to
Cross detection mouth con and send video signal.If now extracting video transmission cable, video signal is sent and is obstructed, AUX
Channel can not receive return signal, this kind of situation, the testing circuit of video transmission cable produce Aux_err_pul signal and
Aux_err_clr signal is to computer C2, after the calculating of computer C2 and its peripheral logical circuit, at computer
When C2 counting continuously receives 128 Aux_err_pul pulse signals, transmission will be cut off to application processor AP's
Cable_det signal, this kind of situation, application processor AP sends chip_pd_hv=1, ono shot pulse circuit O1
Producing a reset value to reset enumerator, testing circuit recovers to original state, it is achieved the detection of video transmission cable
Circuit just resets whole circuit, returns to holding state, after waiting that video transmission cable accesses next time, then detects.
2, to non-MyDP cable or the detection of slimport cable:
Under original state, switch S11, switch S12 and switch S13 Guan Bi, and switch S21 and switch S22 break
Open, when there being the video transmission cable being connected to testing circuit by detecting mouth con will detect mouth con, due to cable
Pull down resistor, the voltage at detection mouth con is had to be pulled low, and time lower than 3.3-DV, the second comparator B2's
Output signal is high level, i.e. A=1, and the first enumerator C1 and the first comparator B1 starts working.First counting
Device C1 is used for timing, and the timing at the first enumerator C1 reaches time interval T0, and this time interval T0 is according to video
After the length of transmission cable sets, the output of the first comparator B1 becomes high pressure, and the first comparator B1 starts to judge
The video transmission cable accessed is slimport cable.The most then processed by cable_det signalisation application
Device AP.AUX channel is received detection mouth con by S_aux switch simultaneously；If it is not, the most in sequence
Guan Bi switchs S21 and switch S22, disconnects switch S11, S12 and switch S13, by detection mouth con by switch S21,
ID_out signal gives application processor AP, the application processor AP of mobile device judge that detection mouth con is connected
The type of video transmission cable.Send usb_det signal to application processor AP simultaneously.
Detect the type of the video transmission cable that mouth con is connected utilizing application processor AP to detect after, permissible
The voltage V_cwire at voltage VT_unplug and the detection mouth con set by application processor AP is utilized to detect
Whether video transmission cable is pulled out, and specifically, compares voltage V_cwire and the size of voltage VT_unplug, its
In, the value of voltage VT_unplug needs to be configured according to AP situation over there so that when cable inserts,
V_cwire<VT_unplug；When cable is extracted, V_cwire > VT_unplug.Therefore, by comparing V_cwire
And VT_unplug, it is possible to whether detection video transmission cable is pulled out.
But, owing to the concrete magnitude of voltage of voltage VT_unplug is not easily found, so having no idea by comparing
V_cwire and VT_unplug judges whether video transmission cable is pulled out, for this kind of situation, application processor
Usb_plug signal can be set to 1 by AP, and when non-slimport cable is pulled out, AP puts usb_plug signal
It is 0.Therefore, by usb_plug signal, it is possible to whether detection video transmission cable is pulled out.
The testing circuit of video transmission cable, in the case of detecting that video transmission cable is pulled out, resets whole circuit,
Return to holding state, after waiting that video transmission cable accesses, then detect next time.
Additionally, the embodiment of the present invention additionally provides a kind of video frequency output chip, this video frequency output chip mainly includes this
The testing circuit of any one video transmission cable that bright embodiment foregoing is provided.
As can be seen from the above description, present invention achieves and avoid the pull-up resistor in application processor and detection
Influencing each other between the pull-up resistor in circuit, it is possible to ensure the testing circuit accuracy in detection to transmission of video circuit.
Therefore, the testing circuit of the video transmission cable that the embodiment of the present invention is provided, reach the inspection of raising video transmission cable
Survey the effect of degree of accuracy.
The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for the skill of this area
For art personnel, the present invention can have various modifications and variations.All within the spirit and principles in the present invention, made
Any modification, equivalent substitution and improvement etc., should be included within the scope of the present invention.
Claims (6)
1. the testing circuit of a video transmission cable, it is characterised in that including:
DC source (vdda)；
First switches set, including the first switch (S11) and second switch (S12), wherein, described first switch
And described second switch (S12) has an identical on off state, and described first switch (S11) (S11)
It is closure state with the original state of described second switch (S12)；
First resistance (R2), the first end is connected with described DC source (vdda), and the second end is by described the
One switch (S11) is connected to detect mouth, and wherein, described detection mouth is used for connecting described video transmission cable；
Second resistance (R3) and the 3rd resistance (R4), wherein, the first end of described second resistance (R3) with
Described DC source (vdda) is connected, and described second switch (S12) is connected to described second resistance (R3)
The second end and the first end of described 3rd resistance (R4) between, the second end of described 3rd resistance (R4) is even
Being connected to signal ground, the resistance of described second resistance (R3) is identical with the resistance of described first resistance (R2), institute
The resistance stating the 3rd resistance (R4) is preset resistive value；
Second switch group, including the 3rd switch (S21), the first end of described 3rd switch (S21) is used for connecting
The application processor of mobile device, the second end of described 3rd switch (S21) is connected to primary nodal point, wherein,
Described primary nodal point is the node between described first switch (S11) and described detection mouth, described 3rd switch
(S21) original state is off-state, and described mobile device is for regarding by the transmission of described video transmission cable
Frequently；And
First comparator (B1), first input end is connected to described primary nodal point, and the second input is connected to second
Node, outfan is for the input voltage and described first of the first input end described first comparator (B1)
In the case of the input voltage of the second input of comparator (B1) differs, output triggers described first switch
(S11), described second switch (S12) and described 3rd switch (S21) switching on off state triggering signal,
Described secondary nodal point is the node between described second switch (S12) and described 3rd resistance (R4).
Testing circuit the most according to claim 1, it is characterised in that described testing circuit also includes:
AUX channel, is connected to described primary nodal point, for electric by described transmission of video in described mobile device
In the case of cable transmission video, receive return signal；
Reset circuit, is connected with described AUX channel, returns described in not receiving at described AUX channel
In the case of letter in reply number, resetting described testing circuit is original state.
Testing circuit the most according to claim 2, it is characterised in that described first switches set also includes the 4th switch
(S13), described 4th switch (S13) and described first switch (S11) have identical on off state, institute
State testing circuit also to include:
Second comparator (B2), first input end is connected to described unidirectional current by described 4th switch (S13)
Source (vdda), the second input is connected to described primary nodal point, and outfan is for described second comparator (B2)
The input voltage of first input end and the input voltage not phase of the second input of described second comparator (B2)
In the case of Tong, output enables signal.
Testing circuit the most according to claim 3, it is characterised in that described testing circuit also includes:
Enumerator, input is connected with the outfan of described second comparator (B2)；
First d type flip flop, D input is connected with the outfan of described first comparator (B1), and clock is believed
Number input is connected with described enumerator, and Q output is connected with described application processor；
Second d type flip flop, D input connects low level signal, clock signal input terminal and described enumerator phase
Connecting, Q output output controls the control signal of described first switches set on off state；And
3d flip-flop, D input connects high level signal, clock signal input terminal and described enumerator phase
Connecting, Q output output controls the control signal of described second switch group on off state.
Testing circuit the most according to claim 4, it is characterised in that described reset circuit includes:
Ono shot pulse circuit, is all connected with described application processor and described enumerator, wherein, described
In the case of the Q output transmission low level signal extremely described application processor of the first d type flip flop, described application
Processor output high level signal is to described ono shot pulse circuit, to reset described enumerator.
6. a video frequency output chip, it is characterised in that include the transmission of video according to any one of claim 1 to 5
The testing circuit of cable.
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| WO2016172879A1 (en) | 2015-04-29 | 2016-11-03 | 广东欧珀移动通信有限公司 | Method for identifying types of cables, power adaptor and cable |
| CN106792131B (en) * | 2016-12-23 | 2019-08-02 | 东软集团股份有限公司 | Data transmission method and device |
| CN110190641B (en) * | 2019-04-29 | 2022-04-05 | 维沃移动通信有限公司 | Charging control circuit, terminal equipment and data line |
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| US6654840B1 (en) * | 1998-05-19 | 2003-11-25 | Sega Enterprises, Ltd. | Connection cable identification mechanism |
| KR101303945B1 (en) * | 2006-10-25 | 2013-09-05 | 삼성전자주식회사 | Apparatus to output signal of HDMI device and method thereof |
| CN100495053C (en) * | 2006-11-24 | 2009-06-03 | 华为技术有限公司 | Method, apparatus and system for identifying type of cables and cable transfer apparatus |
| CN101563619B (en) * | 2006-12-21 | 2012-07-18 | 德雷格医疗系统股份有限公司 | A cable detection system |
| CN101227032A (en) * | 2007-11-28 | 2008-07-23 | 华为技术有限公司 | Single board and cable connector for connecting single board and cable |
| CN101701987B (en) * | 2009-06-11 | 2013-08-07 | 浙江图维电力科技有限公司 | Method for analyzing and recognizing phase of cable and device thereof |
| US8601173B2 (en) * | 2010-06-30 | 2013-12-03 | Silicon Image, Inc. | Detection of cable connections for electronic devices |
| CN102751602A (en) * | 2012-06-27 | 2012-10-24 | 华为技术有限公司 | E1 cable connector, cable type detection circuit board and method |
| JP2014168181A (en) * | 2013-02-28 | 2014-09-11 | Seiko Instruments Inc | Operational amplifier |
| CN203242716U (en) * | 2013-04-09 | 2013-10-16 | 青岛海信移动通信技术股份有限公司 | Battery, battery type detection circuit and mobile terminal |
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