CN104660247B - A kind of bidirectional interface circuit - Google Patents
A kind of bidirectional interface circuit Download PDFInfo
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Abstract
The invention provides a kind of bidirectional interface circuit, the bidirectional interface circuit includes：Input interface, the enabled interface of input, input sink, output interface, output driver, output overcurrent protector.The bidirectional interface circuit of the present invention can carry out two-way signaling transmission by single signal wire；With overcurrent protection function, electric current that can be in automatic detection circuit finds that automatic shutdown circuit is protected during over-current phenomenon avoidance.After Failure elimination, interface circuit recovers normal work automatically.And the bidirectional interface circuit extends the IO level ranges of industrial camera internal microprocessor, input, output level scope is set to reach 30V.Interface circuit signal transmission delay is less than 5us, much smaller than the 30~50us of delay for the interface circuit being made up of photoelectrical coupler.When interface circuit is applied into industrial camera, the control accuracy to associated components such as camera, flash lamps can be significantly improved so that the shooting of image and the gating of Supported Speedlights reach more preferable synchronous effect.
Description
Technical field
The present invention relates to field of machine vision, and in particular to a kind of industrial camera for Machine Vision Detection it is two-way
Interface circuit.
Background technology
NI Vision Builder for Automated Inspection has been widely used on production line, and industrial camera is as in NI Vision Builder for Automated Inspection
" eyes ", it can be used for shooting testee, so as to carry out testee the detection of each side.Pass through industrial camera
I/O interface, can control industrial camera shooting, control external light source gating and communicated with miscellaneous equipment.
In order to meet the protection to the microprocessor of industrial camera, the I/O interface circuitry for being currently used for industrial camera leads to
Often it is made up of photoelectrical coupler, photoelectrical coupler can realize that input signal is isolated with what microprocessor inputted.But photoelectricity coupling
The delay time of clutch is generally in tens microseconds, for the time for exposure is similarly the industrial camera of tens microseconds, delay
Overlong time, this can cause the shooting of image and the gating of Supported Speedlights asynchronous.
Interface circuit based on photoelectrical coupler can also include multichannel I/O signal, but can only often be carried out per road signal
One-way transmission, wanting progress transmitted in both directions can then make circuit excessively complicated.When the external equipment for needing to communicate is a lot, it may appear that
The input signal not enough more than needed phenomenon of output signal；Conversely, also it is possible to.This, which has resulted in I/O interface, to make full use of,
Inconvenience is brought for user.In addition, the trend toward miniaturization of industrial camera is more and more obvious in recent years, cause its internal structure
And circuit design is more and more compacter.The unidirectional I/O signal of multichannel has not met the trend of Miniaturization Design.
Application No. CN201320883908 patent describes a kind of bidirectional interface circuit.The knot of the bidirectional interface circuit
Structure is as shown in Figure 1.As illustrated, when the first controller output signal, second controller reception signal：Switch transistor T 2 is closed all the time
Disconnected, the first controller exports grid of the high level to overcurrent protective switch pipe T1, T1 conductings, and Current Limiting Diodes D1 is turned on, and second
The sending and receiving end of controller receives the low level signal sent from the first controller；First controller exports low level and protected to excessively stream
The grid of switch transistor T 1 is protected, T1 shut-offs, Current Limiting Diodes D1 cut-offs, the sending and receiving end of second controller is received from the first controller
The high level signal sent.When second controller output signal, the first controller reception signal：Overcurrent protective switch pipe T1 begins
Shut-off eventually, second controller export base stage or grid of the high level to switch transistor T 2, T2 conductings, and Current Limiting Diodes D1 ends, the
The sending and receiving end of one controller receives the low imput sent from second controller by current-limiting resistance R1；Second control
Device processed exports base stage or grid of the low level to switch transistor T 2, T2 shut-offs, and Current Limiting Diodes D1 is turned on, and the first supply voltage V1 leads to
Overvoltage adjusts resistance R2 and Current Limiting Diodes D1 and provides efficient level pull-up, the first control for the sending and receiving end of the first controller
The sending and receiving end of device can detect the high level input signal sent from second controller.
But there is problems with the bidirectional interface circuit scheme of Application No. CN201320883908 patent introduction：
1st, using metal-oxide-semiconductor as over-current protection device, it is impossible to cut off the electric current in circuit.If wire harness is shorted to other
Power supply, and overcurrent protective switch pipe T1 is opened simultaneously, as long as the failure for producing excessively stream does not eliminate, just has very high current stream always
T1 is crossed, T1 or exterior strands are possible to burn out because of persistent fever.According to Fig. 1 as can be seen that metal-oxide-semiconductor is switched on and off
It is controlled by the first controller, therefore metal-oxide-semiconductor can not carry out automatic protection according to the electric current flowed through in circuit.
2nd, overcurrent protective switch pipe is mounted in the first controller end and controlled by the first controller, the letter of interface circuit
Control is coordinated in number stream direction by the first controller and second controller, if two controllers are not worked good, can cause signal
Can not normal transmission.
3rd, the high value that the first controller and second controller receive is the first supply voltage V1 magnitude of voltage.The
One supply voltage V1 magnitude of voltage is no more than the maximum voltage that the I/O pin of the first controller and second controller can bear
Value.The maximum voltage value that the I/O pin of usual controller can bear is not over 5V, and industry spot would generally use 24V straight
Power supply is flowed, therefore common interface circuit can not widely use in industry spot.
The content of the invention
In view of the above-mentioned problems, the present invention is desirable to provide a kind of height that data double-way transmission can be realized by single signal wire
Fast interface circuit, it can either realize that two-way signaling transmits, and and can enough protects two lateral circuits injury-free.So not only can root
According to the practical application of user, flexible configuration is carried out to I/O signal transmission direction, improve I/O port signal wire utilization rate and
I/O communication speed, the area of circuit board can also be reduced, be advantageously implemented the miniaturization of industrial camera.
Specifically, the present invention provides a kind of bidirectional interface circuit, it is characterised in that the bidirectional interface circuit includes：
Input interface, the enabled interface of input, input sink, output interface, output driver, output overcurrent protector,
There is one way conducting device, the first end of the one way conducting device connects described respectively in the input sink
Input interface and the enabled interface of the input, the second end connection signal transmssion line of the one way conducting device；The input makes
Energy interface is used to control the one way conducting device；The output interface is used to receive the signal externally sent；The output is driven
Dynamic device is used for the signal received in response to the output interface and produces corresponding output signal, and the of the output driver
One end is connected with the output interface, and the second end is connected to the signal transmssion line through the output overcurrent protector.
Further, when the bidirectional interface circuit is in input state, the enabled interface of input is to described unidirectional
The anode of conduction device exports the first level signal, and when the interface circuit is in output state, the input is enabled to be connect
Mouth exports second of level signal to the anode of the one way conducting device.
Further, the interface circuit is used to connect industrial camera and the signal transmssion line, the industry shooting
Machine has microprocessor, and the input interface, input enable interface and output interface micro- place with the industrial camera respectively
Reason device is connected, also, when the interface circuit is in input state, the microprocessor is defeated to the enabled interface of the input
Enter high level, low level is exported to the output interface；When the interface circuit is in output state, the microprocessor to
The enabled interface input low level of input, the signal for needing to send to output interface output.
Further, the input sink includes：First resistor R1, second resistance R2 and diode D1, described first
The anode of resistance R1 the first pin, the first pin of the second resistance R2 and the diode D1 links together, described
Second resistance R2 second pin is connected with the input interface, and the second pin of the first resistor R1 is with inputting enabled connect
Mouth is connected, and the negative electrode of the diode D1 is connected to the signal transmssion line.
Further, the diode D1 is Schottky diode.
Further, the output driver includes：3rd resistor R3, the 4th resistance R4 and triode Q1, described
The base stage of three resistance R3 the first pin, the 4th resistance R4 the first pin and the triode Q1 links together；Described
Three resistance R3 second pin is connected with the output interface, the second pin of the 4th resistance R4, the triode Q1
Emitter stage and grounding pin link together；The colelctor electrode of the triode Q1 is through the output overcurrent protector and the letter
Number transmission line is connected.
Further, the triode Q1 is NPN triode or NMOS tube.
Further, the output overcurrent protector includes the 5th resistance R5.
Further, in the opposite side of the signal transmssion line, pull-up power supply and pull-up resistor R6 are connected with.
Preferably, the 5th resistance R5 is thermistor, it is highly preferred that the 5th resistance is positive temperature coefficient temperature-sensitive
Resistance.
In a kind of preferred implementation, the input interface of the interface circuit, the enabled interface of input, output interface are used respectively
It is connected in target device (for example, microprocessor of industrial camera).Input interface, for from external reception level signal
To target device.The enabled interface of input and output interface are respectively used to receive electric signal from microprocessor, with control interface
Working condition.
Output driver mentioned in this article is used to produce corresponding output signal in response to the signal of output interface.Output
Driver can directly utilize the level signal of output interface, can also produce corresponding electricity based on the instruction of output interface
Ordinary mail number.Output overcurrent protector is used for the size for limiting output current, when output current is excessive, output overcurrent protector energy
It is enough correspondingly to reduce output current.
In another implementation, inputting enabled interface is connected with the microprocessor of target device, but even
It is connected to a constant voltage source.One I/O pin of microprocessor can be saved using this connected mode.
Technique effect
1) interface circuit of the invention can carry out two-way signaling transmission by single signal wire；
2) interface circuit of the invention has overcurrent protection function, electric current that can be in automatic detection circuit, finds excessively stream
Automatic shutdown circuit (or current value is limited under predetermined value) is protected during phenomenon, prevents that the input or output current is excessive
Burn out interface circuit.After Failure elimination, interface circuit recovers normal work automatically.
3) interface circuit of the invention extends the IO level ranges of industrial camera internal microprocessor, prevents external electrical
Pressing through height causes microcontroller to be burned.The IO level ranges of microprocessor are typically not greater than 5V, and the interface circuit of the present invention
Input, output level scope can reach 30V.
4) directions of signal flow of interface circuit is only controlled by industrial camera internal microprocessor, not by other microprocessors
Or controller control, simplify communication process.
5) interface circuit signal transmission delay is less than 5us, and in the prior art, in order to mouthful circuit that achieves a butt joint protection and
Isolation generally use contains the interface circuit of photoelectrical coupler, the interface circuit generally delay being made up of photoelectrical coupler for 30~
50us。
When the interface circuit of the present invention is applied into industrial camera, can significantly improve to phases such as camera, flash lamps
Close the control accuracy of part so that the shooting of image and the gating of Supported Speedlights reach more preferable synchronous effect.
Brief description of the drawings
Fig. 1 is a kind of circuit structure diagram of bidirectional interface circuit of the prior art；
Fig. 2 is the theory diagram according to the bidirectional interface circuit of one embodiment of the invention；
Fig. 3 is the circuit diagram of the mongline bidirectional interface circuit in embodiment illustrated in fig. 2；
Fig. 4 be industrial camera microcontroller by interface circuit to external signal line send data when with another equipment
Interface connection schematic diagram；
Fig. 5 is the mongline bidirectional interface circuit theory diagram according to another embodiment of the present invention.
Embodiment
Embodiment one
Fig. 2 and 3 respectively illustrates the theory diagram and circuit structure diagram of one embodiment of the present of invention.As shown in Fig. 2
In the present embodiment, bidirectional interface circuit is drawn by the input sink with current-limiting function, output driver, overcurrent protector, INPUT
Pin, INPUT_EN pins, OUTPUT pins, Line+ pins, GND pin composition.
As shown in figure 3, the input sink with current-limiting function is made up of resistance R1, resistance R2, Schottky diode D1；It is defeated
Go out driver to be made up of resistance R3, resistance R4, NPN triode (or NMOS tube) Q1；Overcurrent protector is made up of thermistor R5.
In the present embodiment, the bidirectional interface circuit is used for the microprocessor and external equipment for connecting industrial camera, example
Such as the controller of flash lamp.
As shown in figure 3, the bidirectional interface circuit be located at the microprocessor (or controller) of industrial camera I/O pin and
Between external signal line, for realizing transmitted in both directions of the data on single signal wire.INPUT pins and microprocessor (or control
Device processed) IO input pins connection, for the signal from signal wire to be inputed to the I/O pin of microprocessor.INPUT_EN draws
Pin is connected with the IO output pins of microprocessor (or controller), and it is as the enabled interface of input.The level of INPUT_EN pins
It can determine that input sink is in running order or closed mode.OUTPUT pins and microprocessor (or controller)
IO output pins connect, for receiving corresponding level signal from microprocessor.Line+ pins connect with external signal line.Connect
Ground pin GND is connected with the GND of microprocessor (or controller).
As shown in figure 3, resistance R1 the first pin, resistance R2 the first pin connect with Schottky diode D1 anode
Together.Resistance R2 second pin is connected with INPUT pins；Resistance R1 second pin is connected with INPUT_EN pins.Xiao
Special based diode D1 negative electrode, semistor R5 the first pin and Line+ pins link together.Temperature-sensitive electricity
Resistance R5 second pin is connected with triode Q1 colelctor electrode；Resistance R3 the first pin, resistance R4 the first pin and three poles
Pipe Q1 base stage links together.Resistance R3 second pin is connected with OUTPUT pins；Resistance R4 second pin, triode
Q1 emitter stage and GND pin links together.Q1 can be NPN triode or NMOS tube.The grid of NMOS tube,
Source electrode, drain the base stage for corresponding to NPN triode respectively, emitter stage, colelctor electrode.
The course of work of the bidirectional interface circuit in the present embodiment is introduced respectively in terms of inputting and exporting two below.
1) microcontroller receives the course of work of data by interface circuit from external signal line
Microcontroller by interface circuit from external signal line receive data when, it is necessary to input sink by interface circuit
Working condition is arranged to, output driver is set to off closed state.The IO output pins of microcontroller are to interface circuit
INPUT_EN pins export high level, you can input sink is arranged into working condition；The IO output pins of microcontroller to
The OUTPUT pins output low level of interface circuit, you can close output driver；When output driver is closed, outlet line
In there is no electric current to flow through, therefore overcurrent protector is also at closed mode.
After the interface circuit enters reception state, INPUT pin cans pass through signal wire according to external equipment
It is transferred to the voltage of Line+ pins and produces corresponding input signal to microprocessor.
Specifically, when the voltage that external equipment is transferred to Line+ pins by signal wire is high level VIHWhen, Schottky
Diode D1 can end, then the voltage for being now transferred to INPUT pins is the voltage of INPUT_EN pins.Need what is illustrated
It is that high level mentioned herein is that comparatively, because when interface circuit is in reception state, INPUT_EN can be exported
Anode of the high level to D1, so, the level differences of the level and INPUT_EN that simply enter Line+ pins are insufficient to allow D1
Conducting, is construed as high level.
In addition, even if D1 is by but because the voltage of INPUT_EN pins is high level, INPUT pins and micro- place
The IO input pins of reason device, which still believe that, receives high level.A height isolated through D1 is have received equivalent to INPUT pins
Level signal, the high level signal do not change because of the signal received at Line+, therefore, even if outside input one is too high
Level any damage will not be also brought to microprocessor.
When the voltage for being transferred to Line+ pins is low level VILWhen, Schottky diode D1 is turned on and forward conduction voltage drop
For VFD1, then INPUT pin voltages are VIL+VFD1.The forward conduction voltage drop V of usual Schottky diodeFD1<0.2V, as long as
VIL+VFD1No more than the maximum V of microprocessor IO input pin low level threshold voltagesILmax, it is possible to think have received
Low level.
The current-limiting function of input sink is realized by current-limiting resistance R1 and Schottky diode D1.When from signal wire
When the voltage for being transferred to Line+ pins is low level, electric current flows out from INPUT_EN pins, by R1, D1, Line+ pin and
Outer signal line, flow ultimately into the ground of load end.Adjust R1 resistance, you can the current value of limitation interface circuit output, because
This will not be damaged to external loading.When it is high level to be transferred to Line+ pin voltages, Schottky diode D1 cut-offs,
The electric current for flowing into interface circuit is Schottky diode D1 reverse leakage current, and usual electric current is microampere order, therefore will not be docked
Mouth circuit damages.
The wide-voltage range of input sink is realized by Schottky diode D1.Under normal circumstances, microcontroller
Otherwise the high level that IO input pins receive can be burnt out the I/O pin of microcontroller no more than its power supply VCCIO, but
It is after adding Schottky diode D1, can solve this problem well.It is transferred to when from signal wire or OUTPUT pins
The voltage VIN of Line+ pins>INPUT_EN-VFD1When, Schottky diode D1 is in cut-off state, is transferred to INPUT pins
Voltage be always the voltage of INPUT_EN pins, even if occurring high level at Line+, will not also burn out microcontroller.Institute
As long as to be transferred to the maximum reverse DC voltage V that the voltage VIN ＜ Schottky diodes of Line+ pins can be bornRDC, just
Interface circuit and microcontroller will not be burnt out, and can ensure that the IO input pins of microcontroller receive high level.So,
The high level scope of the IO input pins of microcontroller has brought up to V by VCCIORDC, usual VCCIO is no more than 5V, and VRDCCan
To reach 30V, i.e. the high level scope of the IO input pins of microcontroller has been extended to 30V by 5V, compatible can more set
It is standby to be communicated.
If Line+ ends are connected by external signal line and the input pin of other equipment accidentally, then equivalent to outside
The all input circuits in both ends of signal wire, electric current is not now had in circuit and is flowed through, the both ends of external signal line will not damage
It is bad.
2) microcontroller sends the course of work of data by the bidirectional interface circuit of the present invention to external signal line
Microcontroller by interface circuit to external signal line send data when, as long as the input sink by interface circuit
Closed state is set to off, output driver can work.Therefore it may only be necessary to by the IO output pins of microcontroller to interface circuit
INPUT_EN pins output low level.
Due to output driver be open collector output, therefore to external signal line send data when, be in receiving terminal
External pull-up resistor, as shown in figure 3, resistance R6 is pull-up resistor, EXVCC is pull-up power supply, and pull-up power supply can be according to reception
The level standard at end is selected.
When being sent out signal, it is necessary to which microprocessor carries out an anti-phase processing to the signal to be sent.Work as microcontroller
The IO output pins of device to the OUTPUT pins of interface circuit send high level when, NPN triode Q1 conducting, Line+ is to outside
Signal wire sends low level, low level value VOL=Q1 tube voltage drop UCE+ thermistor R5 pressure drop VR5；As the IO of microcontroller
Output pin to the OUTPUT pins of interface circuit send low level when, NPN triode Q1 cut-off, Line+ is to external signal line
Send high level, high level VOH=external power supply EXVCC magnitude of voltage.
In addition, thermistor R5 is added in the present embodiment also between D1 and Q1.Utilize thermistor resistance and temperature
Directly proportional characteristic, realize the function that overcurrent protection is carried out to output driver.The electric current of output driver is by temperature-sensitive electricity
Heat can be produced when hindering R5, when heat is more than a certain degree, thermistor R5 resistance can increase sharply.When resistance R6 occurs
When short-circuit, EXVCC power supplys are directly connected to Line+ pins.Now, if Q1 is turned on, then flow through thermistor R5 moment electricity
Stream is very big, and thermistor R5 can generate heat rapidly, and its resistance moment becomes big decades of times, therefore can rapidly reduce and be flowed into NPN tri-
Pole pipe Q1 current value, prevents Q1 to be burned.Using thermistor as overcurrent protector very simple, without any controller
It is controlled.When the electric current in output driver is more than the tripping current of thermistor, the resistance of thermistor will be rapid
Become big, so as to reduce the electric current for flowing through driver.When Failure elimination, the resistance of thermistor returns to original resistance, defeated
Go out driver can and continue normal work.
Output driver is open collector output, and output high value is determined by external power source EXVCC, can be according to connecing
The interface level of receiving end is configured.As long as the maximum electricity that EXVCC can be born between the collector and emitter no more than Q1
Press UCEmax, Q1 would not damage.Usual UCEmax60V can be reached, therefore the voltage range of output level is very wide.
As shown in figure 4, if Line+ ends are connected by external signal line and the open-collector output of other equipment accidentally
Connecing, in this case two-way open collector output-parallel, external signal line level can be dragged down by exporting low level driver,
Electric current is flowed into the low level driver of output from external power supply EXVCC by pull-up resistor R6.Resistance R6 plays metering function,
Terminal device will not be caused to damage.
Embodiment 2
Fig. 5 shows the schematic block diagram of another embodiment of the present invention.In this embodiment, interface circuit INPUT_EN
Pin directly connects with the power supply VCCIO of the I/O pin of microprocessor (or controller).After so connecting, input sink
Just without closing.When microcontroller sends data by interface circuit to external signal line, input sink can receive defeated
Go out the data of driver transmission, but this has no effect on the work of output driver, and can save microprocessor (or control
Device) I/O pin.When the I/O pin resource anxiety of microprocessor (or controller), this scheme can be used.
The bidirectional interface circuit of the present invention has overcurrent protection function, prevents the input or output current is excessive from burning out interface electricity
Road；And it extends the IO level ranges of industrial camera internal microprocessor, realizes that plurality of devices is communicated.The present invention
Interface circuit signal transmission delay be less than 5us, by contrast, the existing interface circuit being made up of photoelectrical coupler is generally delayed
For 30~50us.Therefore, the interface circuit of the present invention is used for the industrial camera that the time for exposure is musec order, can caused
The shooting of image and the gating of Supported Speedlights reach good synchronous effect.
Although the principle of the present invention is described in detail above in conjunction with the preferred embodiments of the present invention, this area skill
Art personnel are it should be understood that above-described embodiment is only the explanation to the exemplary implementation of the present invention, not to present invention bag
Restriction containing scope.Details in embodiment is simultaneously not meant to limit the scope of the invention, in the spirit without departing substantially from the present invention and
In the case of scope, any equivalent transformation based on technical solution of the present invention, simple replacement etc. are obvious to be changed, and is all fallen within
Within the scope of the present invention.
Claims (9)
1. a kind of bidirectional interface circuit, it is characterised in that the bidirectional interface circuit includes：Input interface, the enabled interface of input,
Input sink, output interface, output driver, output overcurrent protector, there is one-way conduction device in the input sink
Part, the first end of the one way conducting device connects the input interface and the enabled interface of the input respectively, described unidirectionally to lead
The second end connection signal transmssion line of logical device；The enabled interface of input is used to control the one way conducting device；It is described defeated
Outgoing interface is used to receive the signal externally sent and is sent to the output driver；The output driver is described for responding
The signal that output interface receives, and corresponding output signal is produced, the first end of the output driver connects with the output
Mouth is connected, and the second end is connected to the signal transmssion line through the output overcurrent protector.
2. bidirectional interface circuit according to claim 1, it is characterised in that when the bidirectional interface circuit is in input shape
During state, the anode of input enabled interface to the one way conducting device exports the first level signal, when interface electricity
When road is in output state, the enabled interface of input exports second of level signal to the anode of the one way conducting device.
3. bidirectional interface circuit according to claim 1, it is characterised in that the interface circuit is used to connect industrial shooting
Machine and the signal transmssion line, the industrial camera have microprocessor, the input interface, the enabled interface of input and output
Microprocessor of the interface respectively with the industrial camera is connected, also, when the interface circuit is in input state, institute
Microprocessor is stated to the enabled interface input high level of the input；When the interface circuit is in output state, micro- place
Device is managed to the enabled interface input low level of the input.
4. bidirectional interface circuit according to claim 1, it is characterised in that the input sink includes：First resistor
R1, second resistance R2 and diode D1, the first pin of the first resistor R1, the first pin of the second resistance R2 and institute
The anode for stating diode D1 links together, and the second pin of the second resistance R2 is connected with the input interface, described
First resistor R1 second pin is connected with inputting enabled interface, and the negative electrode of the diode D1 is connected to the signal transmission
Line.
5. bidirectional interface circuit according to claim 4, it is characterised in that the diode D1 is Schottky diode.
6. bidirectional interface circuit according to claim 1, it is characterised in that the output driver includes：3rd resistor
R3, the 4th resistance R4 and triode Q1, the first pin of the 3rd resistor R3, the 4th resistance R4 the first pin and described
Triode Q1 base stage links together；The second pin of the 3rd resistor R3 is connected with the output interface, and described
Four resistance R4 second pin, the emitter stage of the triode Q1 and grounding pin link together；The collection of the triode Q1
Electrode is connected through the output overcurrent protector with the signal transmssion line.
7. bidirectional interface circuit according to claim 6, it is characterised in that the triode Q1 be NPN triode or
NMOS tube.
8. bidirectional interface circuit according to claim 1, it is characterised in that the output overcurrent protector includes the 5th electricity
Hinder R5.
9. bidirectional interface circuit according to claim 1, it is characterised in that in the opposite side of the signal transmssion line, connect
It is connected to pull-up power supply and pull-up resistor R6.
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| CN107611951B (en) * | 2017-10-24 | 2020-04-07 | 深圳市博诺技术有限公司 | Protection circuit of automobile bus communication line |
| CN108768381B (en) * | 2018-08-27 | 2024-01-23 | 深圳市中科蓝讯科技股份有限公司 | GPIO circuit and chip |
| CN112306936A (en) * | 2020-10-23 | 2021-02-02 | 珠海格力电器股份有限公司 | Isolation circuit |
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| CN101552605A (en) * | 2009-05-19 | 2009-10-07 | 北京时代民芯科技有限公司 | An interface circuit capable of tolerating high voltage input |
| CN103294629A (en) * | 2013-04-26 | 2013-09-11 | 深圳市宏电技术股份有限公司 | Interface switching circuit and device |
| CN203761362U (en) * | 2013-12-30 | 2014-08-06 | 联合汽车电子有限公司 | Bidirectional interface circuit |
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| CN104660247A (en) | 2015-05-27 |
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