CN207717935U - Switching signal detection circuit with self-diagnostic function - Google Patents
Switching signal detection circuit with self-diagnostic function Download PDFInfo
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- CN207717935U CN207717935U CN201721862514.3U CN201721862514U CN207717935U CN 207717935 U CN207717935 U CN 207717935U CN 201721862514 U CN201721862514 U CN 201721862514U CN 207717935 U CN207717935 U CN 207717935U
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Abstract
The utility model provides the switching signal detection circuit with self-diagnostic function, belongs to metering signal detection field, including：Resistance R1, and with the concatenated resistance R2 of resistance R1, it is equipped with POW_CTR pins in the one end of resistance R1 far from resistance R2, SW_IO pins and capacitance C1 are equipped between resistance R1, resistance R2, one end ground connection of the capacitance C1 far from SW_IO pins, the other ends of the resistance R2 far from resistance R1 is switching signal input interface.By interrupting or inquiring detection method, the software approach such as ADC detection methods and the controllable mode of hardware circuit power supply cooperate, it realizes under the premise of meeting detection work, with lower power consumption, when input signal short circuit, timing intermission power supply method can be automatically switched to by the power supply of control circuit and coordinate inquiry detection method, avoid generating extra power consumption, influence product power supply service life.
Description
Technical field
The utility model belongs to metering signal detection field, more particularly to carries the switching signal detection electricity of self-diagnostic function
Road.
Background technology
With the development of the times with the progress of science and technology, smart instrumentation popularized.Switching value technology is because of tool
Have the advantages that simple, reliable, at low cost, is used widely in smart instrumentation.If button trigger, valve in place, flow
Count the metrical pulse signal etc. of output.In above application, detecting system can first pass through external interface and receive on-off model, warp
Signal is passed to controller by decompression or filtering etc. after processes, then by internal interface, carries out final analysis and processing.
Since the use environment of intelligence instrument is complicated and radix is huge, interface inevitably breaks down.
Such as：When the short circuit of interior external tapping or internal interface are opened a way and are interfered, the big problem of power consumption is will produce, and only in electricity
It when pond electricity has consumed, can just identify, cause the waste of energy；When the connection signal line hair between external interface and signal source
It when raw broken string, can not be identified, can only be investigated after finding without counting by its Interface status in the prior art
And repair.The economic dispute be easy to causeing in this way between enterprise and user, service provider and consumer.
Therefore, it is highly desirable to increase self-diagnostic function in intelligence instrument, it is ensured that when a failure occurs it, can examine in time
It measures failure cause and carries out respective handling, so as not to influence the normal operation of other function modules.Summarizing the prior art
The deficiency of middle switching value method devises low-power consumption and can be timely herein by taking industrial Intelligent gas meter based on internet of things as an example
Detect inside and outside interface fault, a kind of switching value system with self-diagnostic function, the above-mentioned reality of effective solution
Border problem.
Utility model content
In order to solve shortcoming and defect existing in the prior art, the utility model provides interruption and inquiry detection method pair
Switching signal is detected, to reduce the switching signal detection circuit with self-diagnostic function of detection power consumption.
In order to reach above-mentioned technical purpose, one side the utility model provides the inspection of the switching signal with self-diagnostic function
Slowdown monitoring circuit, the switching signal detection circuit, including：
Resistance R1, and with the concatenated resistance R2 of resistance R1, draw equipped with POW_CTR in the one end of resistance R1 far from resistance R2
Foot is equipped with SW_IO pins and capacitance C1, one end ground connection of the capacitance C1 far from SW_IO pins, electricity between resistance R1, resistance R2
The resistance other ends of the R2 far from resistance R1 is switching signal input interface.
Optionally, it is connected with signal wire burn out detection on the switching signal input interface of the switching signal detection circuit
Circuit；
It is connected with switch detection circuit in the output end of the signal wire break detection circuit, breaks in the signal wire and examines
The output end of slowdown monitoring circuit is connected with
Passive signal output circuit or
Active signal output circuit or
Passive signal output circuit and active signal output circuit；
Wherein, signal is also associated between the output end of signal wire break detection circuit and active signal output circuit to turn
Change circuit.
Optionally, in the signal wire break detection circuit, it is equipped with triode Q1, is connected in the base stage of triode Q1
The first control terminal for sending out control signal is equipped with resistance R4 between control terminal and base stage, connects at the collector of triode Q1
It is connected to resistance R3, the emitter ground connection of triode Q1.
Optionally, in the switching signal detection circuit, it is additionally provided with source signal conversion circuit, including：
Include source follower circuit, includes the current collection of the grid and triode Q4 of metal-oxide-semiconductor Q3 and triode Q4, metal-oxide-semiconductor Q3
Extremely it is connected, the drain electrode of metal-oxide-semiconductor Q3 is through diode D2 connection signal conversion circuits；
Resistance R7 is equipped between the collector and the source electrode of metal-oxide-semiconductor Q3 of triode Q4, the base stage of triode Q4 is through resistance
R8 is connected with the second control terminal.
Optionally, further include in the active signal circuit and have source follower circuit connect active signal conversion circuit,
Including：
The drain electrode connecting valve signal input interface of metal-oxide-semiconductor Q2, metal-oxide-semiconductor Q2, the source electrode ground connection of metal-oxide-semiconductor Q2, metal-oxide-semiconductor Q2's
Grid is connected with resistance R5, is grounded through resistance R6 in the one end of resistance R5 far from metal-oxide-semiconductor Q2, resistance R6 is far from the another of ground terminal
Hold connection signal output circuit.
Optionally, between the input interface in switch detection circuit and the output end of signal wire break detection circuit
It is additionally provided with voltage protection circuit, the output end of voltage protection circuit is as external interface.
The advantageous effect that technical solution provided by the utility model is brought is：
1, by on-off model detection circuit, switching value software algorithm, (signal wire breaks self diagnosis software algorithm
Detection and the detection of internal interface open circuit), the mutual cooperation of wireless communication function makes product in use, can monitor automatically
On off state and Interface status, including：When the control that the input signal cable being connect with external interface breaks or connect with internal interface
Device pin desoldering processed etc. can detect when occurring abnormal to carry out processing, and notify related personnel by remote alarms in time.
2, can be by interrupting or inquiring detection method, the software approach such as ADC detection methods and hardware circuit power supply are controllable
Mode cooperates, and realizes under the premise of meeting detection work, has lower power consumption can when input signal short circuit
Timing intermission power supply method is automatically switched to by the power supply of control circuit, and coordinates inquiry detection method, avoids generating work(
Consumption, influences product power supply service life.
4, it realizes to compatibility active or without source input signal.By switching signal detection circuit and it is active arrive passive signal
The design of conversion circuit, then match combination switch inspection software algorithm, realizes the input of passive or active signal, different active of voltage
Signal inputs, the compatibility of normally opened and normally closed input signal, the mixing of one or more single input signals.
5, controllable by detection circuit power supply, when product by long-term use after, component can be reduced due to device aging and
The probability of failure.In addition, when circuit breaks down, power supply can be disconnected, protect the circuit in product not by shadow
It rings.
Description of the drawings
It, below will be to needed in embodiment description in order to illustrate more clearly of the technical solution of the utility model
Attached drawing is briefly described, it should be apparent that, the accompanying drawings in the following description is only some embodiments of the utility model, for
For those of ordinary skill in the art, without creative efforts, other are can also be obtained according to these attached drawings
Attached drawing.
Fig. 1 is the structural schematic diagram of the switching signal detection circuit provided by the utility model with self-diagnostic function；
Fig. 2 is the structural schematic diagram of passive switch signal deteching circuit provided by the utility model；
Fig. 3 is the structural schematic diagram of active signal conversion circuit provided by the utility model；
Fig. 4 is the structural schematic diagram of external interface signals line break detection circuit provided by the utility model；
Fig. 5 is the structural schematic diagram of voltage protection circuit provided by the utility model；
Fig. 6 is the flow diagram of internal interface open circuit detection provided by the utility model；
Fig. 7 is the alternative flow diagram of internal interface open circuit detection provided by the utility model；
Fig. 8 is the flow diagram of signal wire wire break detection method provided by the utility model；
Fig. 9 is the system block diagram provided by the utility model based on switching signal detection circuit.
Specific implementation mode
It is clearer for the structure and advantage that make the utility model, the structure of the utility model is made below in conjunction with attached drawing
It is further described through.
Embodiment one
One side the utility model provides the switching signal detection circuit with self-diagnostic function, as shown in Figure 1, described
The concrete structure of switching signal detection circuit be resistance R1, and with the concatenated resistance R2 of resistance R1, in resistance R1 far from resistance
One end of R2 is equipped with POW_CTR pins, and SW_IO pins and capacitance C1 are equipped between resistance R1, resistance R2, and capacitance C1 is separate
One end of SW_IO pins is grounded, and the other ends of the resistance R2 far from resistance R1 is switching signal input interface.
In force, switch detection circuit POW_CTR is connect with controller pin, SW_IO and another pin of controller
Connection.R1 is as pull-up resistor, when button is not pressed, SW_IO pins is made to draw the determination state for setting high level.Resistance R2 makees
For protective resistance and sampling resistor.In passive switch signal deteching circuit, as protective resistance, when SW_IO pins export height
Button is pressed when be connected with GND level simultaneously, prevents SW_IO and GND short-circuit.Sampling resistor function is for detection circuit event
Barrier uses when breaking.
100k may be selected preferably, Type Selection Principle in R1 resistances：
(1) when button is not pressed, according to controller data handbook (databook is different, and voltage is different), in this control
In device processed, high level differentiates that voltage threshold is：SW_IO pin voltages are higher than 0.7 times of POW_CTR high level voltages.Such as
When POW_CTR high level voltages are 3V, SW_IO pin voltages are more than 2.1V.
(2) when the button is pressed, the lower the electric current of generation the better.The low level judgement of controller pin can be according to control
Device databook designs, and in this controller, low level differentiates that voltage threshold is：The voltage of SW_IO pins is less than 0.3 times
POW_CTR high level voltages.Such as：POW_CTR voltages are 3V, and 100k resistance of contacting, maximum generates electric current and is
I0=30uA.SW_IO pin voltages are less than 0.9V.
Preferably, when button is not pressed, R2 resistance does not work 100 Ω of R2 resistance selections.When the button is pressed,
R1 connects with R2 resistance, and forms bleeder circuit, and the voltage after partial pressure will follow the sampling principle of SW_IO.
Such as：After button is pressed, SW_IO pin voltages are less than 0.9V, then calculation formula：
→POW_CTR×R2/(R1+R2)<0.9V
→R2<42k
C1 filter capacitor capacitance type selectings：C1 filter capacitors range can be between (0.01nF~1uF).The utility model is
Compatible burn out detection function, using the nonpolarity ceramic condensers of 0.1nF as preferred.
Based on the switching signal detection circuit hereinbefore proposed, passive signal and active signal can be detected.
Passive signal refers to the on-off model that can export low level and vacant state, and button, tongue tube, relay etc. may be used
Switching device or similar device.The preferred button of the utility model embodiment is as simulation passive switch amount input signal source.It is active
Signal refers to that can export low level and high level state or export hanging and high level state on-off model, can be adopted
Use the equipment or instrument with on-off model as input signal source, such as：The on-off model of gas flowmeter output.
It can individually be inputted, can also be total to as switching signal using passive signal output circuit or active signal output circuit
It is inputted with as switching signal.When using passive switch signal as input signal, active signal conversion circuit can not be selected and had
Source signal output circuit.When using active switch signal as input signal, need active output interface being connected to signal turn
The Vin for changing circuit after converting signal, is connected to signal bus OUT, is linked into the external interface of switch detection circuit.
Passive switch signal deteching circuit, including switch detection circuit and passive signal output circuit are proposed in Fig. 2, are used
It is detected in passive signal.Switch detection circuit POW_CTR is connect with controller pin, SW_IO and controller another
Pin connects.R1 is as pull-up resistor, when button is not pressed, SW_IO pins is made to draw the determination state for setting high level.
Resistance R2 is as protective resistance and sampling resistor.In passive switch signal deteching circuit, as protective resistance, when
SW_IO pins export high level while button is pressed when being connected with GND, prevent SW_IO and GND short circuits.Sampling resistor function
It is to be used when breaking for detection circuit failure.Sampling resistor function is addressed below.
Capacitance C1 is the filter capacitor of switching signal sampling end in switch detection circuit, and effect is after button is pressed,
Moment is connected with GND in resistance R2, filters out keyboard mechanical shaking interference signal, controller is made not will produce erroneous judgement.Believed according to switch
The type of switch S1 is different in number detection circuit, and the testing principle of switching signal detection circuit is described respectively.
Button uses normally opened type, when circuit works normally
1. when button is not pressed, controller is by POW_CTR pin configuration output states, and it is high level to export.Control
SW_IO pin configuration is input state by device processed, and it is high electricity that SW_IO pins can detect current state by pull-up resistor R1
It is flat.Since POW_CTR with SW_IO pin level states are identical, discharge loop can not be constituted, therefore, is generated without electric current.At this time
Inquiry mode may be used in controller or whether interrupt mode detection button S1 is pressed.
2. when button S1 is pressed, resistance R2 is drawn by button connecting pin sets GND, POW_CTR pins, R1, R2,
GND series windings constitute circuit.And after R1 and R2 series winding partial pressures, the low level voltage signal after partial pressure is passed into SW_IO pins.Control
Device has detected low level signal by SW_IO pins, judges that button is pressed.
After detecting that button is pressed, before executing operation, first configure POW_CTR pin levels to by high level low
Level, it is therefore an objective to save the power consumption due to being conducting to GND generations by key pressing.The corresponding operation of button is executed again.Execute completion
Afterwards, timer, timer time Tf1 are enabled (Tf1 can be adjusted according to actual conditions).After timing Tf1 is arrived, stop timing
Device.POW_CTR pins export high level, then are detected to the input signal of button with SW_IO pins, if detecting SW_
I/O pin level is still low level, unchanged, then POW_CTR pins are set low, and restarts timer, until SW_IO draws
Foot detection key-press input signal becomes high level again.This button operation terminates.
If button is detected through n times, after detection number is more than threshold value Cn, SW_IO pins detect always current button
Input signal then carries out sound-light alarm, liquid crystal display error code, and the side for passing through telecommunication still in low level state
Warning message is passed to background server by formula, is handled for technical staff.
In above-mentioned detection process, key press detecting circuit using interruption or inquiry mode, such as detected button before this
After being pressed, then intermittent work mode is used, is periodically detected whether button is released, is restored to open-circuit condition.Reach section
Save the purpose of power consumption.If there is button short trouble, whole controlling switch export low level, and circuit power supply is disconnected,
And it alarms.
Opposite, if button, using Closed type, the workflow of the switching signal detection circuit is：
1. controller is by POW_CTR pin configuration output states, and it is low level to export.Controller matches SW_IO pins
It is set to input state, R2 is drawn by button connecting pin as pull down resistor and sets GND.SW_IO pins detect current state
For low level.
2. whether controller is pressed using timing inquiry mode detection button S1.When timing (T1) time, then (T1 can
Adjusted according to practical application), POW_CTR pins are exported into high level, R1 is divided as pull-up resistor with R2.When waiting
Between after (T2) capacitance C1 charging, voltage sample is carried out by SW_IO pins.Judge whether SW_IO pin levels become high level.Such as
Fruit detects that SW_IO pins are changed to high level, then can determine whether that button is pressed.Otherwise button is not connect down.After the completion of detection, then
Secondary POW_CTR pins export low level, wait for timing to progress cycle detection.Timing needs to consider capacitance C1
The charge and discharge time, when POW_CTR output be high level when, need to wait for time T2, C1 charges, after waiting voltage stabilizations, into
Row detection.When POW_CTR outputs are low level, time T2 is needed to wait for, C1 discharges, and after waiting voltage stabilizations, is detected.
Use timing intermittent power supply with inquiry the matched purpose of detection mode be save since button is normally off, when
The power consumption that POW_CTR is generated when being high level.
Here stand-by period T2 belongs to general knowledge known in this field, and details are not described herein again.
Based on the switching signal detection circuit that the above, the present embodiment propose, what is diagnosed for switching signal
Solution is：
By switching signal detection circuit and the active design to passive signal conversion circuit, then match combination switch inspection software
Algorithm, realizes passive and active input signal, voltage it is different have a source input signal, normally opened and normally closed input signal it is simultaneous
Hold, the mixing of one or more single input signals.When product by long-term use after, component can be reduced and occurred due to device aging
The probability of failure.In addition, when circuit occurs abnormal due to failure, power supply can be disconnected, to protect the circuit in product
It is unaffected.By controlling power supply power supply, when timing does not arrive or system does not work, can power detection circuit electricity
Source disconnects, and detection circuit does not work.The service life of product can be extended.
In addition the switching signal detection circuit uses modularized design, can be combined and tear open according to practical application request
Point.It is not only able to solve the problems, such as background technology, and whether interface is sent out inside or outside system self-diagnosable circuit
Raw failure.When circuit does not need voltage protection function, switching signal can be detected interface and be connected to directly as external interface
On signal bus OUT.Do not select voltage protection circuit.When circuit does not need burn out detection function, signal wire can not be selected disconnected
Line detection circuit.
When circuit is using passive signal as input signal, can not select active to passive signal conversion circuit and active letter
Number output circuit.In addition it can individually defeated as switching signal using passive signal output circuit or active signal output circuit
Enter.It can also input, the Vin on active signal elder generation connection signal conversion circuit can be turned signal collectively as switching signal
It after changing, is connected on signal bus OUT, accesses external interface.
Optionally, in the switching signal detection circuit, it is additionally provided with source signal conversion circuit, including：
Include source follower circuit, includes the current collection of the grid and triode Q4 of metal-oxide-semiconductor Q3 and triode Q4, metal-oxide-semiconductor Q3
Extremely it is connected, the drain electrode of metal-oxide-semiconductor Q3 is through diode D2 connection signal conversion circuits；
Resistance R7 is equipped between the collector and the source electrode of metal-oxide-semiconductor Q3 of triode Q4, the base stage of triode Q4 is through resistance
R8 is connected with the second control terminal.
The active signal conversion circuit for further including in the active signal circuit and thering is source follower circuit to connect, including：
The drain electrode of metal-oxide-semiconductor Q2, metal-oxide-semiconductor Q2 connect input terminal, the source electrode ground connection of metal-oxide-semiconductor Q2, and the grid of MOS pipes is connected with
Resistance R5 is grounded in the one end of resistance R5 far from metal-oxide-semiconductor Q2 through resistance R6, other end connection signals of the resistance R6 far from ground terminal
Output circuit.
In force, the structure of active signal conversion circuit is as shown in figure 3, needed when input signal is active signal
Active signal is converted into passive signal by active signal conversion circuit.Believed using metal-oxide-semiconductor in the utility model embodiment
Preferably, under the premise of using metal-oxide-semiconductor Q2, the operation principle of the signaling conversion circuit is for number conversion circuit：
When the output of VIN signals is high level, metal-oxide-semiconductor Q2 conductings, VOUT exports low level.When the output of VIN signals is low
Level or it is hanging when, metal-oxide-semiconductor Q2 cut-off, the output of OUT no signals.
In signaling conversion circuit, metal-oxide-semiconductor Q2 can use metal-oxide-semiconductor or triode Q2 ' to be replaced mutually.When VIN is in
When vacant state no signal exports, the grid of metal-oxide-semiconductor Q2 is in vacant state, and MOS tube grids vacantly easily lead to the electrostatic of accumulation
It nowhere releases, there is the hidden danger of breakdown.Pull down resistor R6 plays discharge process.
Resistance R5 resistance values range of choice can be between 0.1k~510k, and resistance R5 uses 10k Ω conducts in the present embodiment
It is preferred that.Resistance R6 resistance values range of choice can be between 0.1k~1.5M, and resistance R6 uses 470k Ω as excellent in the present embodiment
Choosing.
Optionally, it is connected with signal wire break detection circuit on the input terminal of the switching signal detection circuit；
It is connected with switch detection circuit in the output end of the signal wire break detection circuit, breaks in the signal wire and examines
The output end of slowdown monitoring circuit is connected with
Passive signal output circuit or
Active signal output circuit or
Passive signal output circuit and active signal output circuit；
Wherein, signal is also associated between the output end of signal wire break detection circuit and active signal output circuit to turn
Change circuit.
In force, in order to realize hereinbefore propose the step of being detected to switching signal, signal wire burn out detection
The concrete structure of circuit is equipped with triode Q1, and the first control terminal for sending out control signal is connected in the base stage of triode Q1,
It is equipped with resistance R4 between control terminal and base stage, resistance R3, the emitter of triode Q1 are connected at the collector of triode Q1
Ground connection.Wire break detection method based on the signal wire break detection circuit embodies in latter embodiment.
Optionally, in the output of the switch signal input end in switch detection circuit and signal wire break detection circuit
Voltage protection circuit is additionally provided between end, the output end of voltage protection circuit is as external interface.
In force, as shown in figure 5, between resistance R2 and input signal circuit, the protection diode that can also connect D1.Its
Effect one is when input signal exception, and protection diode D1 reversely ends, and then protects switch detection circuit will not be because of outside
Interface occurs the exception such as short circuit or external input signal overtension and is burned out.
The operation principle of voltage protection diode D1：When the voltage of input signal is low level, at protection diode D1
In conducting state, when input signal is high level or is hanging, protection diode D1 is in cut-off state, and switching circuit passes through outside
Interface can be detected input signal.
The utility model provides the switching signal detection circuit with self-diagnostic function, including resistance R1, and with electricity
The concatenated resistance R2 of R1 are hindered, POW_CTR pins are equipped in the one end of resistance R1 far from resistance R2, between resistance R1, resistance R2
Equipped with SW_IO pins and capacitance C1, one end ground connection of the capacitance C1 far from SW_IO pins, the other ends of the resistance R2 far from resistance R1
For switching signal input interface.By interrupting or inquiring detection method, the software approach such as ADC detection methods and hardware circuit power supply
Controllable mode cooperates, and realizes under the premise of meeting detection work, has lower power consumption, when input signal short circuit
When, timing intermission power supply method can be automatically switched to by the power supply of control circuit and coordinate inquiry detection method, avoid producing
Raw extra power consumption, influences product power supply service life.
Embodiment two
On the other hand, the utility model embodiment further includes the switching signal inspection applied to the switching signal detection circuit
Survey method, as shown in fig. 6, the switching signal detection method includes the steps that internal interface open circuit detection, specially：
21, the SW_IO pins in switch detection circuit are set to output state, POW_CTR pins are set to input state；
22, it enables SW_IO pins first export high level, exports low level afterwards, it is defeated to SW_IO pins by POW_CTR pins
The level signal gone out is detected；
If 23, SW_IO pins first export high level, exporting low level afterwards, then POW_CTR first detects high level, then
It detects low level, it is normal that SW_IO pins, POW_CTR pins can be explained；
If level change 24, is not detected, illustrate that internal interface breaks down.
Alternatively, the content in step 22 can also be that SW_IO pins is enabled first to export low level, high level is exported afterwards, is passed through
The level signal that POW_CTR pins export SW_IO pins is detected.
According to the replacement content of step 22, step 23 is corresponding can also be if SW_IO pins first export low level, after
High level is exported, then POW_CTR first detects low level, then detects high level, and SW_IO pins, POW_CTR pins can be explained
It is normal.
For step 22,23 interchangeable contents, the switching signal detection method flow chart is as shown in Figure 7.
In force, the protective effect of R2 resistance：If without R2 resistance, when SW_IO pins export high level, just press
Key S1 is in the state being pressed, and will result in SW_IO pins and passes through button S1 and GND short circuits.Increase R2 resistance, works as SW_IO
Pin exports high level, and when button S1 is pressed, and since resistance R2 plays metering function, would not cause short circuit, no
Influence level signal detection.It is again output high level by POW_CTR key configurations, by SW_IO pin configuration after the completion of detection
For input state.Carry out normal switching signal detection.
By interrupting or inquiring detection method, the software approach such as ADC detection methods and the controllable mode of hardware circuit power supply
It cooperates, realizes under the premise of meeting detection work, there is lower power consumption can pass through when input signal short circuit
The power supply for automatically switching detection circuit avoids generating power consumption, influences product power supply service life.
Embodiment three
On the other hand, the utility model embodiment further includes the switching signal inspection applied to the switching signal detection circuit
Survey method, the switching signal detection circuit, further includes signal wire wire break detection method, as shown in Fig. 8, specially：
31, passive signal input interface button S1 is not triggered or active signal input interface CTR2 exports low level, MOS
When pipe Q2 is in cut-off state, input signal is in vacant state.
32, using timing detection pattern, timing Tf3, when timing is not timed out, the output of CTR1 pins is low electricity
Flat, triode Q1 cut-offs, sampling resistor R3 is in vacant state, and no current circuit when diagnostic circuit does not work, does not generate electric current
Consumption.
Optionally, described to work as timing Tf3 then, the work of signal wire break detection circuit, including：
When switch is not triggered, i.e., external interface is in vacant state, is input state by POW_CTR pin configuration,
CTR1 pins export high level, and SW_IO pins are using multiplexing Chip Microcomputer A/D function, i.e. analog to digital conversion function；
Sampling resistor accesses/disconnects control line CTR1 output high level, and sampling resistor is accessed signal bus, pull-up resistor
R1 and protective resistance R2, voltage protection diode D1, sampling resistor R3 contact and divide, and are connected to GND by triode Q1
Current loop is constituted, SW_IO pins carry out AD voltage samples to sampling resistor；
If sampled voltage is less than threshold value Vt, judge that signal wire connection is normal；If sampled voltage is higher than threshold value Vt,
It can determine whether as broken string state；Vt ranging from 0~0.62V are preferably, Vt threshold values are obtained according to actual samples voltage；
After the completion of sampling, sampling resistor accesses/disconnects control line CTR1 output low levels, other two pin is restored to out
OFF signal detects working condition.
In force, when switch is not triggered, that is, it is in vacant state, can is input shape by POW_CTR pin configuration
State, CTR1 pins export high level, and SW_IO pins carry ADC (analog to digital conversion) function using multiplexing microcontroller.It adopts
Sample resistance accesses/disconnects control line CTR1 output high level, and sampling resistor is accessed signal bus.Pull-up resistor R1 and protection electricity
Resistance R2, voltage protection diode D1, sampling resistor R3 contact and divide, and are connected to GND by triode Q1 and constitute electric current time
Road, SW_IO pins carry out AD voltage samples to sampling resistor at this time, if sampled voltage is 0V, can determine whether that signal wire is connected to
Normally, it if sampled voltage is non-zero V, can determine whether as broken string state.After the completion of sampling, sampling resistor accesses/disconnect control line
CTR1 exports low level, other two pin is restored to switching signal detection working condition.
Optionally, described to work as timing Tf3 then, the work of signal wire break detection circuit, including：
The output of POW_CTR pins is high level, and for SW_IO pins using AD functions are multiplexed with, i.e. analog to digital converts work(
Can, sampling resistor accesses/disconnects control line CTR1 output high level, and sampling resistor is accessed signal bus；
Pull-up resistor R1 and protective resistance R2, voltage protection diode D1, sampling resistor R3 contact and divide, and pass through three
Pole pipe Q1 is connected to GND and constitutes current loop, and SW_IO pins carry out AD samplings at this time, according to sampled result combination formula 1,2,3
Judged；
Work as no signal, when external interface is hanging,
V3=V1 × (R2+R3)/(R1+R2+R3)+V2, formula 1；
When there is a signal, when external interface is low level, V3=V1 × R2/ (R1+R2)+V2, formula 2；
When break state when, V3=V1, formula 3；
In above-mentioned ADC sampled voltages calculation formula, if voltage V1 is POW_CTR pin voltages, V 2 is protection diode
Operating voltage, V3 are SW_IO pin AD sampled voltages.
In force, the output of POW_CTR pins is high level, and using ADC is multiplexed with, (analog to digital turns SW_IO pins
Change) function.Sampling resistor accesses/disconnects control line CTR1 output high level, and sampling resistor is accessed signal bus.Pull-up resistor
R1 and protective resistance R2, voltage protection diode D1, sampling resistor R3 contact and divide, and are connected to GND by triode Q1
Current loop is constituted, SW_IO pins carry out AD samplings at this time.Sampled result compares hereafter formula 1, and 2,3 are judged.
When input signal exception (such as：Positive and negative anodes are reversed, short circuit etc.), since CTR1 pin powereds power supply and input are believed
Number power supply differ, therefore, diagnostic circuit is in off working state, will not be affected.
ADC sampled voltage calculation formula
If POW_CTR voltages are V1, protection diode operating voltage is V2, and SW_IO pin AD sampled voltages are V3, then count
Calculating formula is：
1. no signal, interface is hanging
V3=V1 × (R2+R3)/(R1+R2+R3)+V2 (formula 1)
2. having signal, low level
V3=V1 × R2/ (R1+R2)+V2 (formula 2)
3. break state
V3=V1 (formula 3)
R1, R2, R3 and R4 resistance type selecting：
The utility model R1 resistance selections 100k, R2 resistance selection 1k, R3 resistance selection 100k, R4 resistance selection 100k makees
It is preferred.
V1 voltages use 3V, protection diode to use Schottky diode, rated operational voltage 0.3V.
1. no signal, interface is hanging or high level state, brings formula 1 into, acquires sampled voltage V3：
V3=V1 × (R2+R3)/(R1+R2+R3)+V2
=1.8V
2. there is signal, low level brings formula 2 into, acquires sampled voltage V3：
V3=V1 × R2/ (R1+R2)+V2
=0.33V
3. break state, formula 3 is brought into, acquire sampled voltage V3：
V3=V1=3V
It should be noted that burn out detection POW_CTR high level guard time T3 explanations：
The timing range of T3 can select between 20us~1s.The utility model is using 200us as preferred.
The timing of T3 is related to the type selecting of R1 resistance values, C1 capacitances, and to distinguish switch short, open circuit, break three kinds of shapes
State can be obtained by test.
If R1 resistance values and C1 capacitance selective values are larger, C1 needs the longer charging time, just voltage can be made to reach steady
Fixed, when can cause burn out detection, POW_CTR high-level retention times T3 long, average current when periodical line detection detection is big.
If when R1 resistance values and smaller C1 capacitances selection, the charging time of C1 is more short-circuit, but in switch short, then produces
Raw larger short circuit current.If the T3 times are short, the capacitance C1 charging time can be caused shorter, carry out AD samplings, Jiu Huizao at this time
It is relatively low at the voltage detected on C1, then button cannot be distinguished in the voltage under tactile state or broken string state.
It is also proposed based on the switching signal detection circuit and a variety of detection methods, the utility model embodiment proposed above
System block diagram based on switching signal detection circuit as shown in Figure 9.
External input signal component includes burn out detection module (being the break detection circuit in previous embodiment), with
And it is connected to passive switch signal and active switch signal in burn out detection module for generating switching signal, it is opened due to active
OFF signal cannot directly export burn out detection module, therefore be additionally provided with signal conversion module (i.e. in active switch signal output end
For the signaling conversion circuit in previous embodiment).
External input signal component is connected to microcontroller through control signal wire, is connected through external interface by signal lines
Voltage protection circuit, voltage protection circuit are connected with switch detection circuit (i.e. switching signal detection circuit).Switch detection circuit
It is connect by internal interface between microcontroller, to realize power supply control and information collection.Microcontroller is also associated with acousto-optic report
Alert circuit, liquid crystal display circuit and radio communication circuit, to realize the alarm after detecting broken string and to inform control in time
The operations such as end.
The utility model provides passive signal input interface button S1 and is not triggered or active signal input interface CTR2
Low level is exported, when metal-oxide-semiconductor Q2 is in cut-off state, input signal is in vacant state.Using timing detection pattern, when timing
Between Tf3, when timing is not timed out, the output of CTR1 pins is low level, triode Q1 cut-offs, and sampling resistor R3 is in hanging shape
State, no current circuit when break detection circuit does not work, do not generate current drain.When timing Tf3 then, signal wire is disconnected
Line detection circuit works.By interrupting and inquiring detection method, the software approach such as ADC detection methods and hardware circuit power supply are controllable
Mode cooperate, realize meet detect work under the premise of, have lower power consumption, when input signal short circuit,
It can avoid generating power consumption, influence product power supply service life by the power supply of automatic switchover detection circuit.
Each serial number in above-described embodiment is for illustration only, the assembling for not representing each component or the elder generation during use
Sequence afterwards.
The above description is only the embodiments of the present invention, is not intended to limit the utility model, all in the utility model
Spirit and principle within, any modification, equivalent replacement, improvement and so on should be included in the protection model of the utility model
Within enclosing.
Claims (6)
1. the switching signal detection circuit with self-diagnostic function, which is characterized in that the switching signal detection circuit, including：
Resistance R1, and with the concatenated resistance R2 of resistance R1, the one end of resistance R1 far from resistance R2 be equipped with POW_CTR pins,
SW_IO pins and capacitance C1, one end ground connection of the capacitance C1 far from SW_IO pins, resistance R2 are equipped between resistance R1, resistance R2
The other end far from resistance R1 is switching signal input interface.
2. the switching signal detection circuit according to claim 1 with self-diagnostic function, which is characterized in that opened described
It is connected with signal wire break detection circuit on the switching signal input interface of OFF signal detection circuit；
It is connected with switch detection circuit in the output end of the signal wire break detection circuit, in signal wire burn out detection electricity
The output end on road is connected with
Passive signal output circuit or
Active signal output circuit or
Passive signal output circuit and active signal output circuit；
Wherein, signal conversion electricity is also associated between the output end of signal wire break detection circuit and active signal output circuit
Road.
3. the switching signal detection circuit according to claim 2 with self-diagnostic function, which is characterized in that in the letter
In number line break detection circuit, it is equipped with triode Q1, the first control for sending out control signal is connected in the base stage of triode Q1
End is equipped with resistance R4 between control terminal and base stage, resistance R3, the hair of triode Q1 is connected at the collector of triode Q1
Emitter grounding.
4. the switching signal detection circuit according to claim 1 with self-diagnostic function, which is characterized in that opened described
In OFF signal detection circuit, it is additionally provided with source signal conversion circuit, including：
Include source follower circuit, includes the collector phase of the grid of metal-oxide-semiconductor Q3 and triode Q4, metal-oxide-semiconductor Q3 and triode Q4
Even, the drain electrode of metal-oxide-semiconductor Q3 is through diode D2 connection signal conversion circuits；
Resistance R7 is equipped between the collector and the source electrode of metal-oxide-semiconductor Q3 of triode Q4, the base stage of triode Q4 connects through resistance R8
It is connected to the second control terminal.
5. the switching signal detection circuit according to claim 4 with self-diagnostic function, which is characterized in that described active
The active signal conversion circuit for further including in signal circuit and thering is source follower circuit to connect, including：
The drain electrode connecting valve signal input interface of metal-oxide-semiconductor Q2, metal-oxide-semiconductor Q2, the source electrode ground connection of metal-oxide-semiconductor Q2, the grid of metal-oxide-semiconductor Q2
It is connected with resistance R5, is grounded through resistance R6 in the one end of resistance R5 far from metal-oxide-semiconductor Q2, the other ends of the resistance R6 far from ground terminal connects
Connect signal output apparatus.
6. the switching signal detection circuit according to any one of claims 1 to 5 with self-diagnostic function, feature exist
In being additionally provided with voltage protection between the input interface and the output end of signal wire break detection circuit of the switch detection circuit
Circuit, the output end of voltage protection circuit is as external interface.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201721862514.3U CN207717935U (en) | 2017-12-27 | 2017-12-27 | Switching signal detection circuit with self-diagnostic function |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721862514.3U CN207717935U (en) | 2017-12-27 | 2017-12-27 | Switching signal detection circuit with self-diagnostic function |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111474461A (en) * | 2020-03-31 | 2020-07-31 | 南京优倍电气有限公司 | Circuit device for detecting failure of switch of functional safety product |
| CN111522282A (en) * | 2020-05-27 | 2020-08-11 | 北京无线电测量研究所 | Electronic product with shuttle flying knob |
-
2017
- 2017-12-27 CN CN201721862514.3U patent/CN207717935U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111474461A (en) * | 2020-03-31 | 2020-07-31 | 南京优倍电气有限公司 | Circuit device for detecting failure of switch of functional safety product |
| CN111522282A (en) * | 2020-05-27 | 2020-08-11 | 北京无线电测量研究所 | Electronic product with shuttle flying knob |
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