CN107945722A - Pixel current detection range method of adjustment, detection circuit and display device - Google Patents
Pixel current detection range method of adjustment, detection circuit and display device Download PDFInfo
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- CN107945722A CN107945722A CN201810040850.2A CN201810040850A CN107945722A CN 107945722 A CN107945722 A CN 107945722A CN 201810040850 A CN201810040850 A CN 201810040850A CN 107945722 A CN107945722 A CN 107945722A
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/006—Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3233—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3258—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the voltage across the light-emitting element
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Abstract
This disclosure relates to display technology field, more particularly to a kind of detection range method of adjustment, pixel current detection circuit and display device.The detection range method of adjustment is applied to pixel current detection circuit, which is used for the size that pixel current is determined using the first reference voltage and pixel current to be detected generation integral voltage and the transformation period according to used in the integral voltage changes to the second reference voltage；The method of adjustment includes：According to the size of pixel current and the relation of the detection range of detection circuit, the size of the first reference voltage of adjustment and/or the second reference voltage.The disclosure can realize that the detection range of pixel current detection circuit can adjust, so as to improve the accuracy of detection.
Description
Technical field
This disclosure relates to display technology field, more particularly to a kind of detection range method of adjustment, pixel current detection circuit
And display device.
Background technology
Organic Light Emitting Diode (Organic Light Emitting Diode, OLED) display device due to its is frivolous,
The features such as energy consumption is low, brightness is high and reaction speed is fast, increasingly becomes the main product of display field.OLED display
Pixel unit is luminous to realize to OLED light-emitting components supply electric current by drive circuit.Drive circuit generally comprises driving crystal
Pipe, storage capacitors and switching transistor, gate source voltage, threshold voltage and the characteristic size of pixel current transistor driven etc.
Influence.Due to the deviation of OLED manufacturing process, the drift of drive transistor threshold voltage or mobility, the change of driver circuit resistance
Change etc., the pixel current of OLED different pixels unit in use can have differences, and the pixel current of same pixel unit
It can change with use, so as to cause the display defects such as non-uniform light, spot, ghost.
Usually drive circuit is connected in detection circuit by sense wire in correlation technique, detects the reality of pixel current
After the size of border, corresponding electric compensation is carried out.But existing detection circuit detection range is fixed, when OLED use conditions
Or drive circuit changes, or when pixel current and larger initial value deviation, actual pixels electric current may exceed original
Detection range, leads to not the size of accurately detection pixel current.
It should be noted that information is only used for strengthening the reason to the background of the disclosure disclosed in above-mentioned background section
Solution, therefore can include not forming the information to the prior art known to persons of ordinary skill in the art.
The content of the invention
The purpose of the disclosure is to provide a kind of method, circuit and display device for detecting display device driving current, into
And overcome the pixel current detection range caused by the limitation of correlation technique and defect non-adjustable at least to a certain extent
The problem of.
Other characteristics and advantage of the disclosure will be apparent from by following detailed description, or partially by the disclosure
Practice and acquistion.
According to one aspect of the disclosure, there is provided a kind of detection range method of adjustment, applied to pixel current detection circuit,
The detection circuit is used for using the first reference voltage and pixel current to be detected generation integral voltage and according to the product
The transformation period that component voltage is changed to used in the second reference voltage determines the size of the pixel current, the method for adjustment bag
Include：
According to the size of the pixel current and the relation of the detection range of the detection circuit, adjustment first reference
The size of voltage and/or second reference voltage.
In a kind of exemplary embodiment of the disclosure, adjustment first reference voltage or the second reference electricity
The size of pressure includes：
When the pixel current is more than the central value of the detection range, increases first reference voltage and/or subtract
Small second reference voltage；
When the pixel current is less than the central value of the detection range, reduce first reference voltage and/or increasing
Big second reference voltage.
In a kind of exemplary embodiment of the disclosure, adjustment first reference voltage or the second reference electricity
The size of pressure includes：
When the pixel current exceeds the detection range upper limit, increase first reference voltage and/or reduce institute
State the second reference voltage；
When the pixel current exceeds the detection range lower limit, reduce first reference voltage and/or increase institute
State the second reference voltage.
In a kind of exemplary embodiment of the disclosure, determine that the integral voltage is changed to used in the second reference voltage
Transformation period includes：
When the integral voltage starts output, started counting up by a counter；
When the integral voltage changes to the second reference voltage, the counter is set to stop counting；
Determine that the integral voltage changes to the change used in the second reference voltage by the count results of the counter
Time.
In a kind of exemplary embodiment of the disclosure, the method further includes：
The count frequency of the counter is adjusted, the accuracy of detection of the detection circuit is adjusted to target detection essence
Degree.
In a kind of exemplary embodiment of the disclosure：The counter is counted according to clock signal；
The count frequency of the adjustment counter includes：
The frequency of the clock signal is adjusted according to the transformation period.
According to one aspect of the disclosure, there is provided a kind of pixel current detection circuit, including：
Integrating circuit, for utilizing the first reference voltage and pixel current to be detected generation integral voltage；
Timing module, transformation period used in the second reference voltage is changed to for detecting the integral voltage；
Wherein, it is at least one adjustable in first reference voltage and the second reference voltage.
In a kind of exemplary embodiment of the disclosure, the integrating circuit includes：
Operational amplifier, first input end connect the pixel current, and the second input terminal connects first reference voltage,
Output terminal connects the timing module；
Capacitor, is connected between the first input end and output terminal of the operational amplifier；
First switch, is arranged at the first input end, for being switched on or off the pixel current；
Second switch, is arranged between the first input end and output terminal of the operational amplifier, and with the capacitor
It is in parallel.
In a kind of exemplary embodiment of the disclosure, the timing module includes：
Comparing unit, for the comparative result generation triggering letter according to the integral voltage and second reference voltage
Number；
Counting unit, counting is started counting up or terminates for responding the trigger signal.
According to one aspect of the disclosure, there is provided a kind of display device：Including the pixel current described in above-mentioned any one
Detection circuit.
In detection range method of adjustment, detection circuit and display device that the example embodiment of the disclosure provides, by picture
Plain electric current is converted to integral voltage, by measure integrating circuit from the first reference voltage change to the change of the second reference voltage when
Between, pixel current is extrapolated, therefore integration can be adjusted indirectly by adjusting the first reference voltage and/or the second reference voltage
The transformation period of voltage, to realize the adjustment to the detection range of pixel current, enables detection circuit Accurate Determining pixel electric
The size of stream, so as to give corresponding electric compensation in the driving circuit, lifts the display quality of OLED display；The opposing party
Face, the time-consuming length for depending primarily upon transformation period of pixel current detection process in the example embodiment of the disclosure, therefore
It can need to adjust transformation period to suitable level according to actually detected, be more convenient detection.
It should be appreciated that the general description and following detailed description of the above are only exemplary and explanatory, not
The disclosure can be limited.
Brief description of the drawings
Attached drawing herein is merged in specification and forms the part of this specification, shows the implementation for meeting the disclosure
Example, and be used to together with specification to explain the principle of the disclosure.It should be evident that drawings in the following description are only the disclosure
Some embodiments, for those of ordinary skill in the art, without creative efforts, can also basis
These attached drawings obtain other attached drawings.
Fig. 1 schematically shows a kind of structure diagram of pixel current detection circuit in disclosure exemplary embodiment；
Fig. 2 schematically shows the flow chart of detection range method of adjustment in disclosure exemplary embodiment；
Fig. 3 schematically shows a kind of structure chart of pixel current detection circuit in disclosure exemplary embodiment；
Fig. 4 schematically shows the structure chart of another pixel current detection circuit in disclosure exemplary embodiment；
Fig. 5 schematically shows the structure chart of pixel unit circuit in disclosure exemplary embodiment；
Fig. 6 schematically shows the waveform signal of each signal in pixel current detection circuit in disclosure exemplary embodiment
Figure.
Embodiment
Example embodiment is described more fully with referring now to attached drawing.However, example embodiment can be with a variety of shapes
Formula is implemented, and is not understood as limited to example set forth herein；On the contrary, these embodiments are provided so that the disclosure will more
Fully and completely, and by the design of example embodiment comprehensively it is communicated to those skilled in the art.Described feature, knot
Structure or characteristic can be incorporated in one or more embodiments in any suitable manner.
In addition, attached drawing is only the schematic illustrations of the disclosure, it is not necessarily drawn to scale.Identical attached drawing mark in figure
Note represents same or similar part, thus will omit repetition thereof.Some block diagrams shown in attached drawing are work(
Can entity, not necessarily must be corresponding with physically or logically independent entity.These work(can be realized using software form
Energy entity, or these functional entitys are realized in one or more hardware modules or integrated circuit, or at heterogeneous networks and/or place
These functional entitys are realized in reason device device and/or microcontroller device.
It should be noted that in the disclosure, term "one", " one ", "the" and " described " representing there are one or
Multiple key element/parts/etc.；Term " comprising " and " having " is representing the open meaning being included and refer to
Except the key element listed/part/also may be present in addition to waiting other key element/part/etc.；Term " first " and "
Two " etc. only use as mark, are not the limitations to the quantity of its object, order etc..
This example embodiment proposes a kind of detection range method of adjustment, applied to pixel current detection circuit.The inspection
Slowdown monitoring circuit is as shown in Figure 1, can include integrating circuit and the timing module being connected electrically, the method for adjustment of detection range is as schemed
Shown in 2, comprise the following steps：
S11. the first reference voltage and pixel current to be detected generation integral voltage are utilized；
S12. the transformation period according to used in the integral voltage changes to the second reference voltage determines the pixel current
Size；
S13. according to the size of the pixel current and the relation of the detection range of the detection circuit, adjustment described first
Reference voltage and/or second reference voltage.
This example embodiment provide detection range method of adjustment, by adjusting integrating circuit the first reference voltage or
Second reference voltage of timing module, after Indirect method pixel current is converted to integral voltage, changes to the second reference voltage
Transformation period, to realize the adjustment to the detection range of pixel current, improves the accuracy of detection, so that preferably to pixel electricity
Stream carries out electric compensation, improves display quality；On the other hand, the time-consuming of detection process depends primarily upon transformation period, therefore can
Transformation period is adjusted to suitable level according to use conditions such as pixel refresh rate, driving signal frequencies, is more convenient detection.
How explained below by an exemplary embodiment according to the size of pixel current and detection circuit detection range
Relation adjusts the first reference voltage or the second reference voltage.
In the present example embodiment, integrating circuit can be by an operational amplifier OPAMP and a capacitor C group
Into as shown in figure 3, pixel current IpixelInputted from the inverting input of operational amplifier OPAMP, the first reference voltage Vref1From
In-phase input end inputs, and capacitor C is connected between the inverting input and output terminal of operational amplifier OPAMP, capacitor C two
Voltage V between endCFor
VC=Vref1-Vopout=1/C ∫ Ipixeldt
Wherein, C is capacitance, and t is the time.
Since usual detection process only has millisecond even microsecond rank, within the so short time, pixel current IpixelCan
It is considered as the constant unrelated with time t, integral voltage V can be obtainedopoutFor
Vopout=Vref1-Ipixel·t/C
If initial t0When=0, V at this timeopout=Vref1, as t increases, VopoutIt is corresponding to reduce；If work as t=tcWhen,
Vopout=Vref2, i.e., by transformation period tc, integral voltage VopoutChange to the second reference voltage Vref2.Above formula is converted, can
Ipixel=C/tc·(Vref1-Vref2)
Therefore measure transformation period tc, it is possible to calculate pixel current Ipixel。
Timing module has timing range in itself, if its scope is tmin~tmax, then detection circuit is for pixel current
Detection range is
C/tmax·(Vref1-Vref2)~C/tmin·(Vref1-Vref2)
Therefore, the first reference voltage or the second reference voltage are adjusted, and then adjusts both difference Vref1-Vref2, Ke Yishi
Now adjust the detection range of pixel current.
For example, if the size of pixel current differs larger with the central value of detection range, detection effect can be influenced
Fruit, and pixel current is also possible to exceed detection range, testing result can not accurately be reflected current pixel current size.
By adjusting the first reference voltage or the second reference voltage, can make pixel current size be in detection range central value it is attached
Closely.
In one exemplary embodiment, the central value of detection range can be the detection range upper limit and the arithmetic average of lower limit
Value, when pixel current is more than the arithmetic mean of instantaneous value, i.e. Ipixel>1/2·(C/tmin·(Vref1-Vref2)+C/tmax·(Vref1-
Vref2)), by increasing the first reference voltage or reducing the second reference voltage, or increase the first reference voltage at the same time and reduce the
Two reference voltages, make both difference Vref1-Vref2Increase, can make the central value of detection range close to pixel current value, until
Both are equal；Conversely, when pixel current is less than the arithmetic mean of instantaneous value, by reducing the first reference voltage or the reference of increase second
Voltage, or reduce the second reference voltage of the first reference voltage and increase at the same time, make both difference Vref1-Vref2Reduce, it is also reachable
To same purpose.
The definite of detection range central value has a variety of methods, above-mentioned to make the arithmetic mean of instantaneous value of the detection range upper limit and lower limit
Centered on mode be suitable for line style detection range, for type detection range reciprocal, central value can be the detection range upper limit
With the harmonic-mean of lower limit, for exponential type detection range, central value can be that the logarithm of the detection range upper limit and lower limit is put down
Average.The central value of detection range is adjusted to identical with the size of pixel current by the present embodiment, can also only be adjusted to both
It is close, such as the central area of a detection range is set, can be that central value adds and subtracts a surplus, by adjusting the first reference voltage
Or second reference voltage make the size that central area includes pixel current.The central value of detection range is adjusted to and pixel current
Same or like, when farthest can prevent that pixel current fluctuates, its actual numerical value exceeds detection range, and examines
The central area of scope is surveyed with the optimum detection precision in whole detection range.
In one exemplary embodiment, in order to meet the basic demand for detecting pixel current, i.e. pixel current necessarily be in
Within detection range, and detection range is adjusted：When the size of pixel current is beyond the detection range upper limit, i.e. Ipixel
>C/tmin·(Vref1-Vref2), by the first reference voltage of increase or the second reference voltage can be reduced, or increase first at the same time
The second reference voltage of reference voltage and reduction, makes both difference Vref1-Vref2Increase, can expand the upper limit of detection range；Work as picture
When the size of plain electric current is beyond detection range lower limit, i.e. Ipixel<C/tmax·(Vref1-Vref2), can be by reducing the first ginseng
The second reference voltage of voltage or increase is examined, or reduces the second reference voltage of the first reference voltage and increase at the same time, makes both differences
Value Vref1-Vref2Reduce, the lower limit of detection range can be expanded, the size of pixel current is in the detection range after adjustment.
In actual use, it may be necessary to it is detected in the case where not knowing pixel current rated value, then without
Religious services or rituals first calculates transformation period, and actual transformation period may exceed the timing range of timing module in the detection, and causing cannot
Accurate detection, such as the timing range of timing module is 1~16ms, then can not be the situation of 0.3ms or 20ms to transformation period
Accurate timing.Specific in the present exemplary embodiment, when detecting, if having reached the upper limit time of timing module, integration is electric
Pressure does not still change to the second reference voltage, then estimates transformation period beyond the timing upper limit, reduction first that can be appropriate
The second reference voltage of reference voltage or increase, reduces transformation period；If by the lower limit time of timing module, integral voltage
The second reference voltage is just had been changed to, then estimates transformation period and is less than or equal to timing lower limit, increase first that can be appropriate
Reference voltage reduces the second reference voltage, increases transformation period, so as to be in the timing range of timing module.
There can be various ways to the measure of transformation period, in one exemplary embodiment, timing module can pass through it
In counter realize timing.Such as integral voltage start output when, counter starts counting up, and integral voltage changes to the second ginseng
When examining voltage, counter stops counting, and transformation period can be drawn by count results.
Further, in one exemplary embodiment, the count frequency of counter is adjustable, for example, it can be set to counting the cycle
For different stalls such as 1ms, 0.1ms, 0.01ms, to realize different accuracy of timekeeping, its detection for pixel current also shows
Go out different accuracy, count frequency is specifically set so as to the required precision according to detection circuit.Implement in another exemplary
In example, counter can be counted according to clock signal, adjust clock signal frequency equivalent to adjustment count frequency, therefore can root
Clock signal frequency is adjusted according to the required precision of detection circuit.
Except above-mentioned in addition to timing module sets counter, other methods measure transformation period can also be used, such as count
When module can be an oscillograph, the second reference voltage is set in oscillograph, it is readable after integral voltage is inputted the oscillograph
Integral voltage is taken to change to the time of the second reference voltage.It should be noted that the method for said determination transformation period is only to lift
The technical solution of this example embodiment of example explanation, the method for other minutes that those skilled in the art are readily apparent that, all
Belong to the protection domain of the disclosure.
This example embodiment also proposed a kind of pixel current detection circuit, as shown in Figure 1, can include integrating circuit
With timing module, integrating circuit has two input terminals, respectively for the first reference voltage Vref1With pixel current I to be detectedpixel
Input, output terminal output integral voltage Vopout；At least one input terminal of timing module, is connected with the output terminal of integrating circuit,
For integral voltage VopoutInput, timing module measure integral voltage VopoutChange to a default second reference voltage VrefIt is used
Transformation period.
In one exemplary embodiment, as shown in figure 4, integrating circuit can include operational amplifier OPAMP, capacitor C,
First switch JP1 and second switch JP2, wherein, pixel current IpixelCan be defeated from the inverting input of operational amplifier OPAMP
Enter, the first reference voltage Vref1It can be inputted from in-phase input end, capacitor C can be connected to the anti-of operational amplifier OPAMP
Between phase input terminal and output terminal, first switch JP1 can be arranged at the inverting input of operational amplifier OPAMP, control
The pixel current is switched on or off, second switch JP2 can be arranged at inverting input and the output of operational amplifier OPAMP
Between end, and it is in parallel with capacitor C.
Operational amplifier OPAMP and capacitor C is by pixel current IpixelBe converted to integral voltage Vopout.First switch JP1
For being switched on or off the input of pixel current：When first switch JP1 is opened, pixel current IpixelInput detecting circuit, into
The above-mentioned detection process of row；When first switch JP1 is turned off, integral voltage Vopout0 is reduced to rapidly, therefore first switch JP1 can
Start the time of detection with control.Second switch JP2 can control integral voltage VopoutOutput and replacement, work as second switch
When JP2 is opened, integral voltage VopoutThe first reference voltage is reset as, when second switch JP2 is turned off, integral voltage Vopout
To time response, start to export.
For the detection circuit of the present exemplary embodiment, the following institute of working status of first switch JP1 and second switch JP2
State：In original state, first switch JP1 is turned off, when second switch JP2 is opened, detection circuit is initialized, integral voltage
VopoutIt is reset as the first reference voltage Vref1, while timing module can be reset accordingly；When starting detection, by the
One switch JP1 is open-minded, and second switch JP2 shut-offs, integral voltage is from the first reference voltage Vref1To the second reference voltage Vref2Become
Change, timing module measure transformation period, and then obtain pixel current IpixelSize.
Further, first switch JP1 and second switch JP2 can be transistor switching element, be believed by control gate
Number, can more convenient realization be switched on or off.In one exemplary embodiment, the pixel unit circuit knot that m rows n-th arrange
Structure is as shown in figure 5, including drive circuit and detection circuit, drive circuit controls driving switch crystal by data cable Data (n)
Pipe T1, controls scanning switch transistor T2 by scan signal line Gate (m), when driving switch crystal T1 is opened, is driving
The pixel current I from driving high potential ELVDD to driving low potential ELVSS is produced in power cordpixel, OLED is shone；Detection
Circuit is by sense wire Ref (k) to pixel current IpixelSample and then detect, first switch JP1 and second switch JP2 are crystal
Pipe, can set first switch control line Control (m) _ 1 and second switch control line Control (m) _ 2, control the respectively
The signal of one switch JP1 and second switch JP2, first switch control line Control (m) _ 1 are additionally operable to control sense switch
The signal of transistor T3.During original state, first switch control line Control (m) _ 1 is inputted without signal, second switch
JP2 control lines input direct impulse, and first switch JP1 and sense switch transistor T3 is turned off, and second switch JP2 is open-minded, integration
Voltage VopoutIt is reset as the first reference voltage Vref1；During detection state, first switch control line Control (m) _ 1 inputs just
To pulse, input signal, first switch JP1 are not opened with sense switch transistor T3 for second switch control line Control (m) _ 2
Logical, detection circuit is to pixel current IpixelSampling, second switch JP2 shut-offs, integral voltage VopoutStart to export, triggering starts
Detection.
, can also be further by first switch control line Control (m) _ 1 and second switch control in the present exemplary embodiment
Line Control (m) _ 2 processed are arranged to identical with the signal frequency of scan signal line Gate (m), wherein first switch control line
Control (m) _ 1 can be with the same phase of signal of scan signal line Gate (m), second switch control line Control (m) _ 2
With the signal inversion of scan signal line Gate (m), when scanning signal is opened, first switch JP1 is open-minded, and second switch JP2 is closed
It is disconnected；When scanning signal is closed, first switch JP1 shut-offs, second switch JP2 is open-minded, it is achieved thereby that detection circuit and driving
The synchronous interaction of circuit.
The detection circuit of setting transistor switching element is not limited to the concrete form described in the present embodiment, can also there is other
Change, such as second switch control line Control (m) _ 2 can be not provided with, the grid of second switch JP2 by phase inverter with
First switch control line Control (m) _ 1 connects, and can also realize the anti-phase work of first switch JP1 and second switch JP2,
The wiring quantity in circuit can so be reduced；Or sense switch transistor T3 and the first signal control line Control (m) _ 1
Between phase shifter is set, make detection circuit to pixel current IpixelSampling have delay relative to drive circuit, so have enough
Time complete complete sample；Or second switch control line Control (m) _ 2 may be also connected to the clearing of timing module and open
Close, reset by applying signal triggering timing module, the synchronous interaction for realizing whole detection circuit that can be more convenient.
In addition to this example embodiment, the construction of integrating circuit can also be other forms, such as pixel current can be with
Inputted from the in-phase input end of operational amplifier, the first reference voltage can be inputted from inverting input；Capacitor can be set
It is multiple, the pixel current input terminal and output terminal of operational amplifier are connected to by way of series, parallel or connection in series-parallel combine
Between；One or more resistance can also be set in integrating circuit, integral voltage is adjusted to the level for being more suitable for detection.
In order to realize measure transformation period, timing module can include comparing unit and counting unit.In an exemplary reality
Apply in example, as shown in figure 4, comparing unit can include comparator COMP, timing unit can include counter Counter.The
Two reference voltage Vref2The normal phase input end of comparator COMP, integral voltage V can be connectedopoutNegative-phase input can be connected,
As integral voltage VopoutHigher than the second reference voltage Vref2When, the comparison signal CMPOUT of comparator COMP outputs is low level,
On the contrary then comparison signal CMPOUT is high level；For counter Counter, as the comparison signal CMPOUT for receiving high level
When being changed into low level comparison signal CMPOUT, triggering starts counting up, and is changed into when receiving low level comparison signal CMPOUT
During the comparison signal CMPOUT of high level, triggering terminates to count, then can be to integral voltage VopoutHigher than the second reference voltage
Vref2Section timing.
Comparator may be set to be opposite situation with counter：By integral voltage VopoutInput comparator COMP is just
Phase input terminal, by the second reference voltage Vref2The inverting input of input comparator COMP, thus as integral voltage VopoutIt is higher than
Second reference voltage Vref2When, the comparison signal CMPOUT of comparator COMP outputs is high level, on the contrary then comparison signal
CMPOUT is low level；Corresponding counter Counter is to receive low level comparison signal CMPOUT a height of low level
Triggering starts counting up during comparison signal CMPOUT, otherwise triggering terminates to count, then still to integral voltage VopoutHigher than the second ginseng
Examine voltage Vref2Section timing, testing result is constant.
Timing module may be set to be other forms, such as timing module can be arranged to showing for charged supply
Ripple device, sets the second reference voltage in oscillograph, and after integral voltage is inputted, can directly read transformation period；Or can
Timing module to be arranged to the diode and timer of series connection, diode has very low forward conduction voltage, by integration electricity
Press and inputted from the positive side of diode, the second reference voltage is inputted from the reverse side of diode, then integral voltage is higher than
During the second reference voltage, diode is in positive opening state, triggering timing device timing.
In this example embodiment, timing module has timing range, can not be right if transformation period exceeds the scope
Its Accurate Determining.By Ipixel=C/tc·(Vref1-Vref2) understand, when pixel current is constant, transformation period and first is with reference to electricity
Pressure and the difference V of the second reference voltageref1-Vref2It is directly proportional, therefore adjust the first reference voltage or the second reference voltage, so that it may
Transformation period is adjusted in target zone.
For example, when pixel current is too small, cause transformation period too long, during beyond the timing upper limit of timing module, fit
When the first reference voltage of reduction or increase the second reference voltage, or reduce at the same time the first reference voltage and increase second with reference to electricity
Pressure, can shorten transformation period；When pixel current is too big, cause transformation period too short, during less than timing lower limit, appropriate increase
First reference voltage reduces the second reference voltage, or increases the first reference voltage at the same time and reduce the second reference voltage, can make
Transformation period increases, so as to meet detection range.
On the other hand, for identical pixel current, after adjusting the first reference voltage or the second reference voltage, in detection electricity
Different transformation periods is shown as in road, therefore can be adjusted according to actual application environment to desirable level.Such as in order to more
Fast detection, reduces the second reference voltage of the first reference voltage or increase, makes transformation period shorter, or in order to make detection cycle
It is consistent with the cycle of pixel current, increase the first reference voltage or reduce the second reference voltage, make transformation period longer etc..
In addition to adjusting the first reference voltage or the second reference voltage, timing range can also be directly adjusted, is adjusted with reaching
The effect of whole pixel current detection range.Such as the timing module for the present embodiment, the digit of counter can be increased, make meter
The count upper-limit rise of number device, or the count frequency of counter is reduced, each count of counter is represented the longer time, this
Two methods can improve the timing upper limit.
For the pixel current detection circuit of the present exemplary embodiment, the waveform of each signal is as shown in fig. 6, in detection
Before, integral voltage VopoutFor 0, comparison signal CMPOUT output high level, corresponding counter Counter does not produce signal；t0
Moment detection starts, integral voltage VopoutBy the first reference voltage Vref1To the second reference voltage Vref2Linear change, compares letter
Number CMPOUT is changed into exporting low level, and flip-flop number starts counting up；Until tcMoment, integral voltage change to second with reference to electricity
Pressure, comparison signal CMPOUT are changed into exporting high level, and flip-flop number terminates to count.
As it can be seen that count frequency can influence accuracy of detection, if in tcAt the moment, counter is without completely completion last time
Count, then count results are not accurate enough, and the transformation period and the size of pixel current obtained by count results is also not accurate enough.
Therefore, can reduce by increasing the count frequency of counter and count the cycle, make counter it is each count represent it is shorter
Time, so as to shorten the minimum time of day of timing module, can realize the accuracy of detection of higher.For example, if meter
The counting cycle of number device is 1ms, and detection of the timing module to the time may be only accurate to 1ms, if it is 0.1ms to count the cycle,
Detection of the timing module to the time can be as accurate as 0.1ms, its accuracy of detection is the former 10 times.
This example embodiment also provides a kind of display device, including above-mentioned detection circuit.Wherein, the display device
There can be display function including any such as mobile phone, tablet computer, television set, laptop, Digital Frame, navigator
Product or component.
It should be noted that although describing each step of method in the disclosure with particular order in the accompanying drawings, still, this is simultaneously
Undesired or hint must perform these steps according to the particular order, or have to carry out the step ability shown in whole
Realize desired result.It is additional or alternative, it is convenient to omit multiple steps are merged into a step and performed by some steps,
And/or a step is decomposed into execution of multiple steps etc..
Those skilled in the art will readily occur to the disclosure its after considering specification and putting into practice invention disclosed herein
Its embodiment.This application is intended to cover any variations, uses, or adaptations of the disclosure, these modifications, purposes or
Person's adaptive change follows the general principle of the disclosure and including the undocumented common knowledge in the art of the disclosure
Or conventional techniques.Description and embodiments are considered only as exemplary, and the true scope and spirit of the disclosure are by appended
Claim is pointed out.
Claims (10)
1. a kind of detection range method of adjustment, applied to pixel current detection circuit, the detection circuit is used to utilize the first ginseng
Examine voltage and pixel current to be detected generation integral voltage and the second reference voltage institute is changed to according to the integral voltage
Transformation period determines the size of the pixel current；It is characterized in that, the method for adjustment includes：
According to the size of the pixel current and the relation of the detection range of the detection circuit, first reference voltage is adjusted
And/or the size of second reference voltage.
2. detection range method of adjustment according to claim 1, it is characterised in that adjustment first reference voltage
Or the size of second reference voltage includes：
When the pixel current is more than the central value of the detection range, increases first reference voltage and/or reduce institute
State the second reference voltage；
When the pixel current is less than the central value of the detection range, reduce first reference voltage and/or increase institute
State the second reference voltage.
3. detection range method of adjustment according to claim 2, it is characterised in that adjustment first reference voltage
Or the size of second reference voltage includes：
When the pixel current exceeds the detection range upper limit, increase first reference voltage and/or reduce described the
Two reference voltages；
When the pixel current exceeds the detection range lower limit, reduce first reference voltage and/or increase described the
Two reference voltages.
4. according to claim 1-3 any one of them detection range methods of adjustment, it is characterised in that determine the integral voltage
Changing to the transformation period used in the second reference voltage includes：
When the integral voltage starts output, started counting up by a counter；
When the integral voltage changes to the second reference voltage, the counter is set to stop counting；
Determine that the integral voltage changes to the transformation period used in the second reference voltage by the count results of the counter.
5. detection range method of adjustment according to claim 4, it is characterised in that the method further includes：
The count frequency of the counter is adjusted, the accuracy of detection of the detection circuit is adjusted to target detection precision.
6. detection range method of adjustment according to claim 5, it is characterised in that：The counter is according to clock signal meter
Number；
The count frequency of the adjustment counter includes：
The frequency of the clock signal is adjusted according to the transformation period.
A kind of 7. pixel current detection circuit, it is characterised in that including：
Integrating circuit, for utilizing the first reference voltage and pixel current to be detected generation integral voltage；
Timing module, transformation period used in the second reference voltage is changed to for detecting the integral voltage；
Wherein, it is at least one adjustable in first reference voltage and the second reference voltage.
8. pixel current detection circuit according to claim 7, it is characterised in that the integrating circuit includes：
Operational amplifier, first input end connect the pixel current, and the second input terminal connects first reference voltage, output
End connects the timing module；
Capacitor, is connected between the first input end and output terminal of the operational amplifier；
First switch, is arranged at the first input end, for being switched on or off the pixel current；
Second switch, is arranged between the first input end and output terminal of the operational amplifier, and in parallel with the capacitor.
9. pixel current detection circuit according to claim 8, it is characterised in that the timing module includes：
Comparing unit, trigger signal is generated for the comparative result according to the integral voltage and second reference voltage；
Counting unit, counting is started counting up or terminates for responding the trigger signal.
A kind of 10. display device, it is characterised in that：Including claim 7-9 any one of them pixel current detection circuits.
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