CN103646633A - Display device and method for display device to determine internal circuit operating bias - Google Patents

Display device and method for display device to determine internal circuit operating bias Download PDF

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Publication number
CN103646633A
CN103646633A CN201310089281.8A CN201310089281A CN103646633A CN 103646633 A CN103646633 A CN 103646633A CN 201310089281 A CN201310089281 A CN 201310089281A CN 103646633 A CN103646633 A CN 103646633A
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voltage
current
circuit
microcontroller
electric current
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陈世宾
林信男
黄气宝
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Benq Dentsu Co ltd
Benq Corp ltd
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Benq Dentsu Co ltd
Benq Corp ltd
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Abstract

The invention discloses a display device and a method for the display device to determine the internal circuit operating bias. The display device comprises a light source, a voltage conversion circuit, a target current circuit, a microcontroller and a feedback circuit. The voltage conversion circuit is used to convert an external power source into a direct-current power source to drive the light source, wherein a first voltage is outputted by the direct-current power source. When the target current circuit is biased into a preset working mode, the target current circuit is used to control the magnitude of the current flowing through the light source to make the current equal to a second current. The microcontroller is used to detect the value of a third current flowing through the light source and generate a first control signal according to the value of the third current. The feedback circuit is used to cause the voltage conversion circuit to adjust the first voltage according to the first control signal to make the first voltage greater than the minimum voltage value required for maintaining the third current equal to the second current , so that the target current circuit can be biased into the preset working mode, and the electric energy consumed by the target current circuit can be reduced.

Description

Display device and determine internal circuit working bias voltage method for display device
The application is to be dividing an application of September 16, application number in 2011 are 201110274630.4, denomination of invention is < < power control method and display device > > application for a patent for invention the applying date.
Technical field
The present invention, about power control method and display device, refers in particular to a kind of power control method and related display apparatus of supplying in order to control the power supply of the light source of display device.
Background technology
In general, the structure of liquid crystal display please refer to shown in Fig. 1, and liquid crystal display 100 includes liquid crystal panel module 110 and light source 120, and light source 120 is mainly in order to provide light to liquid crystal panel module 110,110 of liquid crystal panel modules are according to driving signal, by light modulation to generate image.Light source 120 needs larger DC voltage (approximately 50 volts of left and right) to drive, and, for the shown brightness of picture of maintenance medium crystal panel module 110 and the homogeneity of color, must supply light source 120 with stable voltage and electric current, to guarantee the consistance of its output brightness.
Wherein, a kind of simple and easy power supply supply and control mode for light source please refer to Fig. 2.As shown in the figure, light source 200 includes a plurality of light source cell 210a～210d, each light source cell may be comprised of a plurality of light-emitting component L respectively, the DC voltage Vdd that light source 200 produces by power supply device 220 carries out power supply supply, and is supplied to respectively one end of each light source cell 210a～210d.In general, light source cell 210a～210d the brightness that produces system relevant with the size of current of flowing through, therefore be the brightness uniformity that can maintain light source cell 210a～210d, light source cell 210a～210d need to control to determine the form of electric current.So the other end of each light source cell 210a～210d will be coupled to the output electric crystal T1～T4 of current mirror 230, can make the to flow through DC current I1～I4 of light source cell 210a～210d of the current replication ability by current mirror 230 is consistent as far as possible.Yet the light-emitting component L forming due to light source cell 210a～210d may have inconsistent that the difference on processing procedure causes.Thus, pressure drop Vdrop1～Vdrop4 on each light source cell is difference to some extent, if the quantity of the light-emitting component L of composition light source cell is more, the difference of pressure drop Vdrop1～Vdrop4 is just more obvious, so the cross-pressure Vce1～Vce4 falling within on electric crystal T1～T4 is also more inconsistent.So, conventionally, when design current mirror 230, can improve cross-pressure Vce1～Vce4 and using as voltage buffering, absorb by this difference of pressure drop Vdrop1～Vdrop4 between light source cell 210a～210d.Yet, although improve the mode of cross-pressure Vce1～Vce4, can effectively absorb the pressure drop difference between light source cell 210a～210d, but such design can cause more meaningless power loss.Particularly, when the difference of pressure drop between light source cell 210a～210d and when not obvious, power loss is obvious especially comparatively speaking.Therefore, known techniques still has weak point urgently to be resolved hurrily.
Summary of the invention
In view of this, one of object of the present invention is to provide a kind of power control method, and it can come according to the mode of operation of circuit dynamic adjustments to be supplied to the power supply (voltage swing or size of current) of light source.Wherein, the cross-pressure on the circuit component that detecting of the present invention is connected with light source is learnt the pressure drop on light source indirectly, to judge whether adjusting power supply supply.Moreover the present invention also provides the mode of judging in advance the optimal bias of light source through microcontroller, accurately set by this suitable power supply extent of supply.Another object of the present invention is to provide a kind of display device, this display device utilizes aforesaid power control method to set the power supply supply of light source, reduces by this power loss.
The invention provides a kind of power control method, the method is in order to control the power supply supply of at least one light source of display device.This display device has voltage conversion circuit, at least one regulating circuit, voltage detection circuit, debug comparator circuit and this light source, wherein this voltage conversion circuit is exported the first DC voltage to this light source, flows into this light source and this regulating circuit of series connection to produce the first electric current.The method comprises: utilize operating voltage that this voltage detection circuit detects this regulating circuit to draw detecting voltage; Utilize this debug comparator circuit to calculate the voltage difference between this detecting voltage and predeterminated voltage; And control this voltage conversion circuit according to this voltage difference, to adjust this first DC voltage.
According to power control method of the present invention, according to this voltage difference, control this voltage conversion circuit, to adjust the step of this first DC voltage, include: when this voltage difference is greater than the first predetermined value, ends this voltage conversion circuit and export this first DC voltage.
According to power control method of the present invention, according to this voltage difference, control this voltage conversion circuit, to adjust the step of this first DC voltage, include: when this voltage difference is greater than the second predetermined value and while being less than the first predetermined value, controls this voltage conversion circuit and reduce this first DC voltage.
According to power control method of the present invention, this display device has a plurality of these light sources and a plurality of regulating circuit, and each string of light is coupled to a regulating circuit, this first DC voltage is supplied to respectively each light source, each light source and each regulating circuit that to produce a plurality of the first electric currents, flow into respectively series connection, this power control method separately includes: utilize operating voltage that this voltage detection circuit detects respectively each regulating circuit to draw the detecting voltage corresponding to each regulating circuit; And utilize this debug comparator circuit to calculate respectively a plurality of voltage differences between each detecting voltage and predeterminated voltage.Further, wherein according to this voltage difference, control this voltage conversion circuit, to adjust the step of this first DC voltage, include: the mean value that calculates these a plurality of voltage differences; When this mean value is greater than the second predetermined value and while being less than the first predetermined value, controls this voltage conversion circuit and reduce this first DC voltage; And at least one in these a plurality of voltage differences is while being greater than this first predetermined value, ends this voltage conversion circuit and exports this first DC voltage.
According to power control method of the present invention, this voltage conversion circuit has pulse width modulation controller, and the step of adjusting this first DC voltage includes: control this pulse width modulation controller and adjust and control this first DC voltage.
The present invention also provides a kind of display device, and this display device comprises: light source, voltage conversion circuit, target current circuit, microcontroller and feedback loop.This voltage conversion circuit is in order to be converted to external power source direct supply to drive this light source, and this direct supply is exported the first voltage.This target current circuit is in order to when this target current circuit is biased while entering default mode of operation, and the magnitude of current and the second electric current essence of controlling this light source of flowing through equate.This microcontroller is coupled to this light source, in order to detect the value of the 3rd electric current of this light source of flowing through, produces accordingly the first control signal.This feedback loop is coupled to this voltage conversion circuit and this microcontroller, in order to first to control signal according to this, control this voltage conversion circuit and adjust this first voltage, make this first voltage be slightly larger than " maintain the 3rd electric current essence and equal this second electric current " required minimum voltage value, biased the entering in this default mode of operation of this target current circuit energy like this, and reduce the electric energy that this target current circuit consumes.
The present invention also provides a kind of display device, and this display device comprises: a plurality of light sources in parallel, voltage conversion circuit, target current circuit, microcontroller and feedback loop.This voltage conversion circuit is converted to direct supply to drive this plurality of light sources in parallel by external power source, and this direct supply is exported the first voltage.This target current circuit is when this target current circuit is biased while entering default mode of operation, and the magnitude of current and the second electric current essence of controlling each light source in these a plurality of light sources in parallel of flowing through equate.This microcontroller is coupled to this light source, in order to detect the value of corresponding the 3rd electric current of this plurality of source current amount summation in parallel of flowing through, produces accordingly the first control signal.This feedback loop is coupled to this voltage conversion circuit and this microcontroller, in order to first to control signal according to this, control this voltage conversion circuit and adjust this first voltage, make this first voltage be slightly larger than " maintain the 3rd electric current essence and equal the quantity that this second electric current is multiplied by these a plurality of light sources in parallel " required minimum voltage value, biased the entering in this default mode of operation of this target current circuit energy like this, and reduce the electric energy that this target current circuit consumes.
Display device as above, when the 3rd electric current equals " quantity that this second electric current is multiplied by these a plurality of light sources in parallel ", this microcontroller reads the current value of this first control signal, and be stored in this microcontroller this current value as optimal bias numerical value, after this display device restarts, this microcontroller can directly read this optimal bias numerical value and control this voltage conversion circuit and export this first voltage.
Display device as above, when the 3rd electric current equals " quantity that this second electric current is multiplied by these a plurality of light sources in parallel ", this microcontroller reads this and first controls the current value of signal and add error tolerance value and obtain optimal bias numerical value, this optimal bias numerical value is stored in this microcontroller, after this display device restarts, this microcontroller can directly read this optimal bias numerical value and control this voltage conversion circuit and export this first voltage.Further, optimal bias numerical value improves direct current (DC) bias 0.5V～5V in order to control this first voltage of this voltage conversion circuit output.
Display device as above, target current circuit more comprises: resistance, in order to determine the size of this second electric current; And current mirror, this current mirror includes the first electric crystal and a plurality of the second electric crystals to should quantity of light source in parallel, wherein this first electric crystal is coupled to this resistance, each this second electric crystal is coupled to this parallel connection light source separately one to one, this second electric current this first electric crystal of flowing through, the flow through summation of these a plurality of the second electric crystal electric currents of the 3rd electric current.
Display device as above, microcontroller is more coupled to this target current circuit, and according to user's input signal, the second control signal that produces accordingly digital form is controlled this target current circuit; This target current circuit more comprises: D/A converting circuit, according to this, second control the size that signal determines this second electric current; With current mirror, this current mirror includes the first electric crystal and a plurality of the second electric crystals to should quantity of light source in parallel, wherein this first electric crystal is coupled to this D/A converting circuit, each this second electric crystal is coupled to this parallel connection light source separately one to one, this second electric current this first electric crystal of flowing through, the flow through summation of these a plurality of the second electric crystal electric currents of the 3rd electric current.
Display device as above, microcontroller is more coupled to this target current circuit, and according to user's input signal, the second control signal that produces accordingly pulse width modulation (PWM) form is controlled this target current circuit; This target current circuit more comprises: filtering circuit, according to this, second control the size that signal determines this second electric current; With current mirror, this current mirror includes the first electric crystal and a plurality of the second electric crystals to should quantity of light source in parallel, wherein this first electric crystal is coupled to this filtering circuit, each this second electric crystal is coupled to this parallel connection light source separately one to one, this second electric current this first electric crystal of flowing through, the flow through summation of these a plurality of the second electric crystal electric currents of the 3rd electric current.
Display device as above more comprises reduction voltage circuit, is coupled between this voltage conversion circuit and this microcontroller, and this reduction voltage circuit is in order to be second voltage by this first lower voltage, and wherein this second voltage is in order to for should the required electric energy of microcontroller; Wherein with respect to this voltage conversion circuit, export this different first voltage, this reduction voltage circuit maintains this fixing second voltage output.
Display device as above, the first control signal is the control signal of pulse width modulation form, and this display device includes: filtering circuit, be coupled between this microcontroller and this voltage conversion circuit, in order to this first control signal is carried out to filtering processing, to produce filtered this first control signal, control this voltage conversion circuit.
Display device as above, first controls the control signal that signal is digital form, and this display device separately includes: digital to analog converter, be coupled between this microcontroller and this voltage conversion circuit, in order to this first control signal is carried out to conversion process, with this first control signal producing after a conversion, control this voltage conversion circuit.
The present invention also provides a kind of and determines internal circuit working bias voltage method for display device, and wherein this display device comprises: light source; Voltage conversion circuit, is converted to direct supply to drive this light source by external power source, and this direct supply is exported the first voltage; Target current circuit, when this target current circuit is biased while entering default mode of operation, the magnitude of current and the second electric current essence that this target current circuit is controlled this light source of flowing through equate; Microcontroller, is coupled to this light source, detects the value of the 3rd electric current of this light source of flowing through, and produces accordingly the first control signal; And feedback loop, be coupled to this voltage conversion circuit and this microcontroller, according to this first control signal, control this voltage conversion circuit and adjust this first voltage; The method comprises step: (1) utilizes this microcontroller to export this first control signal, first makes this lower first voltage of this voltage conversion circuit output, so that the initial value of the 3rd electric current is less than this second electric current; (2) utilize this microcontroller to change gradually this first control signal, make this voltage conversion circuit heighten gradually this first voltage; (3) when the 3rd electric current is when " being less than this second electric current " is transformed into " essence equals this second electric current ", utilize this microcontroller to read the current value of this first control signal at that time, using this current value as the first optimal bias numerical value, and store this first optimal bias numerical value; And (4) utilize this microcontroller with reference to this first optimal bias numerical value, to control this voltage conversion circuit, export this first voltage.
The present invention also provides a kind of and determines internal circuit working bias voltage method for display device, and this display device comprises: a plurality of light sources in parallel; Voltage conversion circuit, is converted to direct supply to drive this plurality of light sources in parallel by external power source, and this direct supply is exported the first voltage; Target current circuit, when this target current circuit is biased while entering default mode of operation, the magnitude of current and the second electric current essence that this target current circuit is controlled each light source in these a plurality of light sources in parallel of flowing through equate; Microcontroller, is coupled to this parallel connection light source, detects the value of the 3rd electric current of these a plurality of source current amount summations in parallel of flowing through, and produces accordingly the first control signal; And feedback loop, be coupled to this voltage conversion circuit and this microcontroller, according to this first control signal, control this voltage conversion circuit and adjust this first voltage; The method comprises step: (1) utilizes this microcontroller to export this first control signal, first make this lower first voltage of this voltage conversion circuit output, the initial value of the 3rd electric current is less than " this second electric current is multiplied by the quantity of these a plurality of light sources in parallel "; (2) utilize this microcontroller to change gradually this first control signal, make this voltage conversion circuit heighten gradually this first voltage; (3) when the 3rd electric current is when " being less than the quantity that this second electric current is multiplied by these a plurality of light sources in parallel " is transformed into " essence equals the quantity that this second electric current is multiplied by these a plurality of light sources in parallel ", utilize this microcontroller to read the current value of this first control signal, using this current value as the first optimal bias numerical value, and store this first optimal bias numerical value; And (4) utilize this microcontroller with reference to this first optimal bias numerical value, to control this voltage conversion circuit, export this first voltage.
Method as above, the method step (3) more comprises: this current value is added to error tolerance value and obtains the second optimal bias numerical value, and store this second optimal bias numerical value; Utilize this microcontroller with reference to this second optimal bias numerical value, control this voltage conversion circuit and export this first voltage, wherein this error tolerance value improves direct current (DC) bias 0.5V～5V in order to control this first voltage of this voltage conversion circuit output.Further, method as above more comprises step: in step (1) before, whether this microcontroller detecting user requires to proofread and correct, if not, this microcontroller skips steps (1) (2) (3), directly read this second optimal bias numerical value, and perform step (4) after substituting this first optimal bias numerical value with this second optimal bias numerical value.
Method as above, more comprises step: in step (1) before, whether this microcontroller detecting user requires to proofread and correct, if not, this microcontroller skips steps (1) (2) (3), directly reads this first optimal bias numerical value, and execution step (4).
In sum, the inventive method can provide suitable DC voltage to give light source accurately, making not have too much voltage can be expended on other circuit of connecting with light source, and, the present invention also can suitable adjusting be supplied to the DC voltage size of light source, and particularly, when light source is under relatively low operating current, the now pressure drop on light source is also lower comparatively speaking, therefore the present invention reduces voltage supply now, to reduce unnecessary power supply consume.
Accompanying drawing explanation
Fig. 1 is the structure of known liquid crystal display.
Fig. 2 is the power supply supply of known light source and the framework of control circuit.
Fig. 3 and Fig. 4 are the explanation first embodiment of the present invention.
Fig. 5 illustrates the application architecture of the second embodiment of the present invention.
Fig. 6 illustrates the circuit framework figure of the third embodiment of the present invention.
Power supply control concept in the 3rd embodiment of Fig. 7 A explanation the inventive method.
Fig. 7 B is the power supply control flow of third embodiment of the invention.
Fig. 8 is an implementing circuit framework of the target current circuit in third embodiment of the invention.
Fig. 9 is another implementing circuit framework of the target current circuit in third embodiment of the invention.
Figure 10 is an implementing circuit framework again of the target current circuit in third embodiment of the invention.
Figure 11 is an enforcement framework of the feedback loop in third embodiment of the invention.
Figure 12 is the another enforcement framework of the feedback loop in third embodiment of the invention.
Figure 13～Figure 15 is the different broad sense implementing procedures of the power supply control flow in third embodiment of the invention.
Figure 16 is the circuit framework figure of the fourth embodiment of the present invention.
Figure 17 is the circuit framework figure of the fourth embodiment of the present invention.
Figure 18～Figure 20 is the different implementing circuit frameworks of the fourth embodiment of the present invention.
Figure 21～Figure 23 is the different broad sense implementing procedures of power supply control flow in the fourth embodiment of the present invention.
Embodiment
In following interior literary composition, will and graphicly set forth concept of the present invention with several embodiment, wherein, the element in difference is graphic with same numeral is representing that it has similar principle of operation and technology effect.Therefore, below in literary composition will omit repeated narration.Moreover mentioned different technologies feature in different embodiment, is not limited to this embodiment in literary composition.In fact, in reasonable category of the present invention, can pass through the suitable modification to certain embodiment, so that it possesses the peculiar technical characterictic of other embodiment.
Please also refer to Fig. 3 and Fig. 4, it illustrates respectively the corresponding process flow diagram of the first embodiment display device 400 applied with it of power control method of the present invention.As shown in the figure, the power supply circuit of display device 400 partly includes (but being not limited to) voltage conversion circuit 410, regulating circuit 420a, voltage detection circuit 430, debug comparator circuit 440, wherein, exportable the first DC voltage Vcc1 of voltage conversion circuit 410 is to the light source 450a of display device 400, and light source 450a connects with regulating circuit 420a.The first DC voltage Vcc1 that voltage conversion circuit 410 is exported will cause the first electric current I cc1 to flow into light source 450a and regulating circuit 420a.The inventive method is in order to control the power supply supply of light source 450a.As shown in Figure 3, the inventive method comprises:
Step 310: utilize the operating voltage of voltage detection circuit 430 detecting regulating circuit 420a to draw a detecting voltage Vdect;
Step 320: the voltage difference Vdiff that utilizes debug comparator circuit 440 to calculate between detecting voltage Vdect and predeterminated voltage Vset;
Step 330: control voltage conversion circuit 410 according to voltage difference Vdiff, to adjust the first DC voltage Vcc1.
Because light source 450a need to control to determine the form of electric current, so one end of light source 450a is coupled to regulating circuit 420a to carry out determining the control of electric current, in an embodiment, regulating circuit 420a may include the output electric crystal T1 of current mirror as shown in Figure 2, carries out determining by this control of electric current.Yet fixed limit is not due to the current mirror framework shown in Fig. 2 for the possible framework of regulating circuit 420a, any exportable circuit framework of determining electric current all belongs to category of the present invention.
Except providing constant current source to light source 450a, regulating circuit 420a can absorb a part of pressure drop, particularly when declining, the electric current of the light source 450a that flows through (may cause because of specific factor, as: the output brightness that downgrades light source 450a), cause while rising on the pressure drop that falls within regulating circuit 420a.And be that the factor of avoiding such causes the pressure drop that falls within on regulating circuit 420a excessive, and then cause unnecessary power supply to consume, therefore in step 310, can utilize the operating voltage of voltage detection circuit 430 detecting regulating circuit 420a to draw detecting voltage Vdect, detecting voltage Vdect can be corresponding to the pressure drop of regulating circuit 420a.Subsequently, just depending on detecting voltage Vdect size, determine whether adjusting the size of the first DC voltage Vcc1 that voltage conversion circuit 410 supplies, and then change the pressure drop of regulating circuit 420a.In the middle of, if Vdect is higher for detecting voltage, the pressure drop that in fact representative falls within on light source 450a comes littlely relatively, in other words, voltage conversion circuit 410 needs suitably to reduce the first DC voltage Vcc1, to avoid meaningless power supply consume (because now light source 450a does not need so large voltage supply).Therefore, in step 320, the convenient voltage difference Vdiff calculating between detecting voltage Vdect and predeterminated voltage Vset with debug comparator circuit 440 of the inventive method, thus, just can differentiate detecting voltage Vdect (corresponding to the pressure drop on regulating circuit 420a) according to voltage difference Vdiff has much actually.
Afterwards, in step 330, the inventive method is controlled voltage conversion circuit 410 according to voltage difference Vdiff, to adjust the first DC voltage Vcc1.In an embodiment, when voltage difference Vdiff is greater than the first predetermined value Value1, the inventive method can be ended voltage conversion circuit 410 output the first DC voltage Vcc.
This is because voltage difference Vdiff is larger more with regard to representing that detecting voltage Vdect is greater than predeterminated voltage Vset,
This situation may represent that the cross-pressure falling within on regulating circuit 420a is quite large, even may surpass the rated operational voltage scope of regulating circuit 420a, therefore in order to protect regulating circuit 420a, the inventive method can be ended the output of voltage conversion circuit 410.Moreover, if voltage difference Vdiff is greater than the second predetermined value Value2, but while being less than the first predetermined value Value1, although the pressure drop that representative falls within on regulating circuit 420a is higher, but be unlikely to cause the damage of regulating circuit 420a or other circuit components, therefore instantly only need to control voltage conversion circuit 410, reduce the first DC voltage Vcc1, can lower the pressure drop falling within on regulating circuit 420a.
Moreover, if display device 400 include more than one light source (as, light source 450b and 450c shown in Fig. 4), and there is an above regulating circuit 420a, when 420b and 420c, the inventive method can utilize operating voltage that voltage detection circuit 430 detects respectively each regulating circuit 420 to draw the detecting voltage Vdect corresponding to each regulating circuit 420a, Vdect1 and Vdect2, and recycling debug comparator circuit 440 calculates respectively each detecting voltage Vdect, a plurality of voltage difference Vdiff between Vdect1 and Vdect2 and predeterminated voltage Vset, Vdiff1 and Vdiff2.Afterwards, the inventive method is by the average voltage Vavg of calculated complex voltage difference Vdiff, Vdiff1 and Vdiff2, and when average voltage Vavg is greater than the second predetermined value Value2 and is less than the first predetermined value Value1, control voltage conversion circuit 410 and reduce the first DC voltage Vcc1.In addition,, for avoiding circuit component damage, as long as when any one in a plurality of voltage difference Vdiff, Vdiff1 and Vdiff2 is greater than the first predetermined value Value1, the inventive method is ended voltage conversion circuit 410 output the first DC voltage Vcc1.The quantity that it should be noted in the discussion above that graphic middle regulating circuit and light source is only the use of explanation, not limitation of the present invention.
In the first embodiment, voltage conversion circuit 410 may have pulse width modulation controller (pulse width modulation controller, PWM controller), regulate by this size of the first DC voltage Vcc1, and the inventive method utilizes this pulse width modulation controller of control to adjust the first DC voltage Vcc1.It should be noted in the discussion above that this mode is not the unique technical means that the present invention adjusts the first DC voltage Vcc1.In other possibilities of the present invention embodiment, other circuit components that should see through adjustment voltage conversion circuit 410 reach the technique effect of adjusting the first DC voltage Vcc1.
The second embodiment of the present invention provides the method that predetermines the required voltage of light source and electric current by microcontroller, thus can be before reality be to light source supply power supply, get rid of in advance the uncertainty that pressure drop difference is brought, and can further avoid unnecessary power consumption.About this embodiment, please refer to Fig. 5, it is based on the designed display device 600 of the second embodiment of the present invention.As shown in the figure, the power suppling part of display device 600 divides and includes (but being not limited to) voltage conversion circuit 610, current-sensing circuit 620 and microcontroller 630.Wherein, exportable the second DC voltage Vcc2 of voltage conversion circuit 610 is to the light source 640a of display device 600.The second DC voltage Vcc2 that voltage conversion circuit 610 is exported will cause the second electric current I cc2 to flow into light source 640a.The characteristic of the present embodiment is the operating current of the corresponding certain luminance of foundation in advance, determines according to this actual bias voltage of light source 640a.In addition,, if display device 600 includes more than one light source (as, light source 640b and the 640c shown in Fig. 5), the inventive method can decide by microcontroller 630 bias voltage of light source 640a～640c integral body.Based on microcontroller, carry out the mode of power supply control, please with further reference to following embodiment.
It is a kind of based on the designed display device of power supply control concept of the present invention that the third embodiment of the present invention provides, its Simple rack composition display device 1100 as shown in Figure 6.Wherein, display device 1100 includes light source 1120, voltage conversion circuit 1130, target current circuit 1140, microcontroller 1150 and feedback loop 1160.
Light source 1120 may include one or more series connection light-emittingdiode, because the brightness of light-emittingdiode is that electric current by the light-emittingdiode of flowing through is determined, therefore must carry out stable Current Control to light source 1120, just can guarantee that light source 1120 energy stable maintenance are in required certain luminance.The power supply of driving light source 1120 is provided by voltage conversion circuit 1130, and voltage conversion circuit 1130 is mainly by external power source P aCbe converted to direct supply P dC, and utilize direct supply P dCcarry out driving light source 1120, wherein, direct supply P dCthere is the first voltage V 1.Voltage conversion circuit 1130 is in order to carry out disposable electric power conversion, and for instance, voltage conversion circuit 1130 can directly convert the electric main of 110V to be about 50V direct supply.Target current circuit 1140 is coupled to light source 1120, mainly light source 1120 is carried out determining Current Control, when voltage conversion circuit 1130 provides direct supply P dCwhile carrying out driving light source 1120, as the first voltage V 1while meeting specific size, target current circuit 1140 can biasedly enter default mode of operation, and so just controllable flow is through the magnitude of current (that is the 3rd electric current I of light source 1120 3), thereby make the magnitude of current be equal in fact the second electric current I 2.In this default mode of operation, the first voltage V no matter 1how to increase by the 3rd electric current I 3maintain and be equal to haply the second electric current I 2.Due to target current circuit 1140 with light source 1120 for connecting, therefore, when target current circuit 1140 operates in this default mode of operation, the first too high voltage V 1can make the pressure drop on target current circuit 1140 raise, form unnecessary power loss.Microcontroller 1150 sees through target current circuit 1140, is also coupled to light source 1120, and its major function is being controlled voltage conversion circuit 1130 by the mechanism of feedbacking, and then regulates the first voltage V 1current voltage value remain on an optimum voltage value, it can reduce the first voltage V as far as possible 1magnitude of voltage, and simultaneously can keep biased this default mode of operation that enters of target current circuit 1140; So reduce the pressure drop on target current circuit 1140, reduce unnecessary power loss.
In order to determine the first voltage V 1optimum voltage value, can detecting flow through the 3rd electric current I of light source 1120 of microcontroller 1150 3current value, and produce according to this first control signal S 1.In the present embodiment, microcontroller 1150 can measure the 3rd electric current I 3node voltage Vx on the resistance R s flowing through learns the 3rd electric current I indirectly 3size (that is Detect (I 3)), yet the equivalent method that any other can detecting current size is also feasible.When producing first, microcontroller 1150 controls signal S 1afterwards, being coupled to the feedback loop 1160 of voltage conversion circuit 1130 and microcontroller 1150 just can be based on the first control signal S 1control voltage conversion circuit 1130 to regulate the first voltage V 1.Because the machine-processed object of back coupling is moderately to adjust the first voltage V 1, avoid unnecessary power loss (the first too high voltage V 1cause 140 pressure drops of target current circuit too high), and can keep light source 1120 simultaneously determine Current Control (the first too low voltage V 1make target current circuit 1140 cannot enter default mode of operation).That is to say the first voltage V 1magnitude of voltage must at least maintain target current circuit 1140 and can normally work, the 3rd electric current I of the light source 1120 of guaranteeing to flow through 3equal in fact the second electric current I 2, to meet the demand of determining Current Control.In practical application, be to ask stablizing on circuit operation, the first voltage V 1to be controlled in to be slightly larger than and " maintain the 3rd electric current I 3essence equals the second electric current I 2" required minimum voltage value.So, target current circuit 1140 can be guaranteed to enter in this default mode of operation, and the while also reduces the unnecessary power consumption (too high pressure drop causes) that target current circuit 1140 causes.Roughly, the power controling machine system in the present embodiment can see through microcontroller 1150 and regulate the first voltage V 1remain on optimum voltage value, determine target current Circuit tuning 1140 bias point, make target current Circuit tuning 1140 can carry out determining Current Control.
Please refer to Fig. 7 A, it illustrates the first voltage V that puts on light source 1120 1the 3rd electric current I with the light source 1120 of flowing through 3between relation.From Fig. 7 A:
(1) AB region: when target current Circuit tuning 1140 is not yet biased in default mode of operation, the 3rd electric current I 3be less than the second electric current I 2, so along with the first voltage V 1increase gradually by the 3rd electric current I 3also can increase thereupon.
(2) CD region: when target current Circuit tuning 1140 is biased in default mode of operation, the 3rd electric current I 3target current value and the second electric current I 2the first voltage V quite, no matter 1increase and decrease how, the 3rd electric current I 3value is maintained and is equal to haply the second electric current I 2state.Therefore, put on the first voltage V on light source 1120 1optimum voltage value be P, that is, distinguish " AB region (the 3rd electric current I 3be less than the second electric current I 2) " and " CD region (the 3rd electric current I 3equal the second electric current I 2) " critical point voltage value.
In order to make the first voltage V 1remain on optimum voltage value P, microcontroller 1150 is first controlled voltage conversion circuit 1130 the first voltage V 1be output in lower value, make the 3rd electric current I 3initial value is less than the second electric current I 2; Then microcontroller 1150 is controlled voltage conversion circuit 1130 again and is improved gradually the first voltage V 1size; And microcontroller 1150 is detected the 3rd electric current I of the light source 1120 of flowing through simultaneously 3along with the first voltage V 1increase the variation producing.When the bias point of finding light sources 1120 when microcontroller 1150 has just entered into region CD by the region AB of Fig. 7 A, that is, the 3rd electric current I 3no longer along with the first voltage V 1increase and change to some extent moment, can regard the first voltage V as 1remained on optimum voltage value P.
Details of operation wherein, process flow diagram and the following explanation of asking for an interview Fig. 7 B.
Step 1201: first, display device 1100 starts, and can enter step 1217 afterwards.
Step 1217: in this step, user can decide the correction program that whether carries out the driving voltage of light source 1120 in its sole discretion.In other words, user can determine to want the first voltage V of driving light source 1120 in this step 1be the magnitude of voltage after predeterminated voltage value or correction, if user determines to proofread and correct, flow process enters step 1203 actually, and microcontroller 1150 will determine the optimum voltage value P for driving light source 1120 again; If not, enter step 1223.
Step 1203: if user requires to proofread and correct the first voltage V 1, microcontroller 1150 reads the first stored optimal bias numerical value C at present bESTand second electric current I 2.
Step 1205: by the first optimal bias numerical value C bESTbe set as the first control signal S 1initial value, and carry out the first control signal S through step 1207-1215 1adjustment, to find the optimum voltage value P of driving light source 1120.
Step 1207: signal S is controlled in microcontroller 1150 outputs first 1to voltage conversion circuit 1130, control voltage conversion circuit 1130 output the first voltage V 1.Wherein, when performing step 1207 for the first time, microcontroller 1150 is according to the first optimal bias numerical value C bESTand produce first, control signal S 1initial value.This first control signal S 1initial value can make the first voltage V of voltage conversion circuit 1130 outputs 1initial value is high as far as possible, and is no more than the optimum voltage value P (specification of composition light-emittingdiode that can be by light source 1120 is calculated) of estimation; The 3rd electric current I of light source 1120 so makes to flow through 3initial value be less than the second electric current I 2, and can shorten step 1207-1215 after a while and approach the required time of optimum voltage value P.
Step 1209: microcontroller 1150 detecting the 3rd electric current I 3value (I 3-sensing).
Step 1211: calculate the second electric current I 2deduct the 3rd electric current I 3the discrepancy delta I of-sensing.
Step 1213: in this step, microcontroller 1150 can judge the relation of Δ I and a preset value.If the first voltage V 1after adjusting, while making Δ I be less than this preset value, can be considered and obtained optimum voltage value P, now jump out " detecting the 3rd electric current I 3adjust the first control signal S 1circulation " (that is, repeating step 1207-1215), and then enter step 1219.Yet, if Δ I is still greater than this preset value, must further adjust again the first voltage V 1to change Δ I, make it be less than this preset value, so flow process will enter step 1215.
Step 1215: due to the first voltage V of now voltage conversion circuit 1130 outputs 1deficiency, causes Δ I to be still greater than this preset value, therefore microcontroller 1150 is by the first control signal S 1value is adjusted and (is made the S after adjusting 1=S originally 1add Δ X, this adjustment can cause the first voltage V 1promote again Δ V; Wherein Δ V can be fixed value (fixed step) or closes the change value (variable step) that is connected in Δ I, as: Δ V=K* Δ I, K is a constant.Then get back to step 1207-1211 and carry out next current difference judgement.So, first control signal S 1to cause voltage conversion circuit 1130 to heighten gradually the first voltage V 1, make the 3rd electric current I 3continue to increase.Once work as target current circuit 1140, enter this default mode of operation, the 3rd electric current I 3essence equals the second electric current I 2, light source 1120 can reach corresponding to the second electric current I simultaneously 2predetermined luminance.
Step 1219: when microcontroller 1150 is adjusted the first voltage V 1the EO that approaches the adjustment circulation (step 1207～1215) of optimum voltage value P, microcontroller 1150 will read the first control signal S 1current value C 1, by current value C 1as the first optimal bias numerical value C bEST, the default driving voltage value in the time of can starting shooting as next time.
Step 1221: by the first optimal bias numerical value C bESTbe stored in the non-volatility memory of microcontroller 1150 or display device 1100, so, when starting shooting next time, when step 1217 judgement user failed call carries out correction program, microcontroller 1150 footpath row read stored optimal bias numerical value C at present bEST, and make output there is optimal bias numerical value C bESTfirst control signal S 1thereby, make the first voltage V 1there is magnitude of voltage P.
Step 1223: when step 1217, if user failed call are proofreaied and correct, can enter this step, microcontroller 1150 will directly be read optimal bias numerical value C stored in non-volatility memory bESTproduce the first control signal S 1, and and then the first voltage V corresponding to generation 1.
In addition,, in another enforcement aspect of the present embodiment, step 1207-1215 will use extrapolation instead and approach rapidly optimum voltage value P, to accelerate the 3rd electric current I 3approach the second electric current I 2speed.For instance, once after the voltage-current relationship of bias point X and bias point Y is learnt, microcontroller 1150 can be passed bias point to Z fast, so can significantly shorten the required time of optimum voltage value P of finding.
In implementing in aspect again of the present embodiment, when circuit is subject to other interference (as: voltage ripple), may make the first voltage V 1decline, and then cause the 3rd electric current I of the light source 1120 of flowing through 3be less than the second electric current I 2.If initial bias voltage is by the first voltage V 1maintain near P point, the first voltage V 1decline may make the bias voltage of light source 1120 fall into region AB, causes comparatively serious current offset.Therefore in step 1219, microcontroller 1150 is by the first control signal S 1current value C 1add error tolerance value C x, obtain the second optimal bias numerical value C bEST' and stored this second optimal bias numerical value C bEST' will make the first voltage V 1remain on the position that magnitude of voltage Q is ordered.Compared to optimal bias numerical value C bESTmake the first voltage V 1remain on magnitude of voltage P point, the second optimal bias numerical value C bEST' make the first voltage V of voltage conversion circuit 1130 output 1improve 0.5V～5V and come magnitude of voltage Q point.When next time start and enter step 1217 while judging that user's failed call carries out correction program, microcontroller 1150 will directly be read the second optimal bias numerical value C stored in non-volatility memory bEST', and make output there is the second optimal bias numerical value C bEST' first control signal S 1thereby, make the first voltage V 1there is magnitude of voltage Q.
Under viewing and admiring environment in difference, user may wish to adjust the brightness of light source 1120, for example: when display device 1100 need be carried out three-dimensional stereo display, brightness that must be higher just can provide good display effect, or when user intends in display device 1100 ornamental film, also wish to have the comparatively bright impression of viewing and admiring.Therefore, the framework that the invention provides several target current circuit 1140 is adjusted the aforesaid Current Control mechanism of determining, and just can meet thus the different display modes of display device 1100, such as: theater pattern, normal mode, 3D pattern etc.Central by changing the second electric current I of 1140 references of target current circuit 2reach.First, once user determines that after required pattern or required brightness, microprocessor 1150 can determine corresponding the second electric current I of this brightness accordingly 2size, afterwards, target current circuit 1140 is just according to the second electric current I 2carry out determining Current Control, and then change the 3rd electric current I of the brightness of actual influence light source 1120 3.
Please refer to Fig. 8, it is an embodiment of target current circuit 1140.Wherein, target current circuit 1140 is mainly comprised of current mirror.Target current circuit 1140 includes resistance R and current mirror 1142.Target current circuit 1140 is the framework based on current mirror, with reference to the second electric current I 2control the 3rd electric current I 3.Wherein, resistance R may be variable resistor, by the variation of resistance value, can change the second electric current I 2size.Current mirror 1142 includes the first electric crystal T1 and the second electric crystal T2, and wherein the first electric crystal T1 is coupled to resistance R, and the second electric crystal T2 is coupled to light source 1120.The second electric current I 2the first electric crystal T1 that flows through, the 3rd electric current I 3the second electric crystal T2 that flows through, the mechanism based on current mirror, the 3rd electric current I 3can with the second electric current I 2maintain certain proportionate relationship (or identical), with based on the second electric current I 2light source 1120 is carried out determining Current Control.In order to make the running of current mirror 1142 normal, electric crystal T1 and electric crystal T2 all can be biased in active region (that is, default mode of operation), therefore, when display device 1100 has just been opened, the 3rd electric current I 3can't catch up with at once the second electric current I 2, reason is that target current circuit 1140 not yet enters default mode of operation, in other words, electric crystal T1 and electric crystal T2 do not enter active region yet.Have when electric crystal T1 and electric crystal T2 all enter active region the 3rd electric current I only 3with the second electric current I 2no matter could be at the first voltage V 1variation under, maintain essence and equate.
Moreover in another embodiment of target current circuit 1140, the operation of brightness adjustment also can see through microcontroller 1150 and carry out.Please refer to Fig. 9, microcontroller 1150 can be coupled to target current circuit 1140, and according to user's input signal S user, produce accordingly second of numerical digit form and control signal S 2control target current circuit 1140.Wherein, user's input signal S usermay carry out the signal producing when brightness arranges for the setting screen menu (on-screen display, OSD) of user by display device 1100.When microcontroller 1150 receives user's input signal S user, can determine the set brightness of user, and corresponding the second electric current I of this brightness 2size.Microcontroller 1150 can output second be controlled signal S 2to the D/A converting circuit 1144 in target current circuit 1140, D/A converting circuit 1144 can be to the second control signal S 2change the voltage V of output analog form analog, and by this voltage V analogsupply with the first electric crystal T1 in current mirror 1142, can determine thus the second electric current I corresponding to the required brightness of user 2size.Similarly, the mechanism based on current mirror (seeing through electric crystal T1 and T2), the 3rd electric current I 3can with the second electric current I 2maintain certain proportionate relationship (or identical), make the brightness that the brightness of light source 1120 can set according to user and controlled by stable.
In addition, in the another enforcement aspect of target current circuit 1140, microcontroller 1150 can be coupled to target current circuit 1140, and according to user's input signal S user, produce accordingly second of pulse width modulation (PWM) form and control signal S 2control target current circuit 1140.About this embodiment, please refer to Figure 10, the difference of itself and above-described embodiment is the second control signal S 2form, this is relevant with the enforcement of microprocessor 1150, different because dissimilar microprocessor can be supported output signal form.Therefore in order to process output format, be, that second of pulse width modulation is controlled signal S 2, target current circuit 1140 more comprises filtering circuit 1146, and filtering circuit 1146 will be to the second control signal S 2carry out filtering processing, and then the voltage V of output analog form analog, and by voltage V analogsupply with the first electric crystal T1 in current mirror 1142, thus, can determine the second electric current I 2size.Be user's input signal S with previous something in common usermay carry out the signal producing when brightness arranges for the setting screen menu (on-screen display, OSD) of user by display device 1100.And, the mechanism based on current mirror, the 3rd electric current I 3can with the second electric current I 2maintain certain proportionate relationship (or identical), make the brightness that the brightness of light source 1120 can set according to user and controlled by stable.
As mentioned above, along with the signal form that 1150 of microcontrollers can be exported is different, the first control signal S that microcontroller 1150 produces 1also have different forms, therefore display device of the present invention 1100 also needs to process the first control signal S by different circuit 1thereby, the first voltage V that regulation voltage change-over circuit 1130 is exported 1.In the embodiment shown in Figure 11, first controls signal S 1for the control signal of pulse width modulation form, now, display device 1100 will separately include filtering circuit 1180, and filtering circuit 1180 is coupled between microcontroller 1150 and feedback loop 1160, in order to the first control signal S 1carry out filtering processing, to produce the first control signal S of (filtered) after filtering 1' control feedback loop 1160, thus the first voltage V that regulation voltage change-over circuit 1130 is exported 1.Moreover, if the first control signal S that microcontroller 1150 produces 1for the control signal of digital form, display device 1100 separately includes the digital to analog converter 1190 shown in Figure 12, and digital to analog converter 1190 is coupled between microcontroller 1150 and feedback loop 1160, in order to control signal S to first of digital form 1carry out conversion process and control signal S to produce first of conversion rear (converted) 1' control feedback loop 1160, thus the first voltage V that regulation voltage change-over circuit 1130 is exported 1.
In addition the direct supply P providing due to voltage conversion circuit 1130, dCvoltage may if desired provide electric power to microcontroller 1150 up to tens of volt, must pass through reduction voltage circuit 1170 and carry out extra voltage transitions, with by the first voltage V 1be reduced to second voltage V 2, therefore, as the first different voltage V of voltage conversion circuit 1130 output 1time, reduction voltage circuit 1170 also can maintain fixing second voltage V 2output.
By microcontroller 1150 and the formed controlling mechanism of target current circuit 1140, can, in a relatively low power loss situation, guarantee that the light source 1120 in display device 1100 can provide stable light source.
Concept based on above, the present invention separately provides a kind of and decides internal circuit working bias voltage method for display device.The element comprising due to this display device is identical with aforesaid embodiment, and those elements have identical principle and operator scheme therefore seldom repeat at this.It should be noted in the discussion above that it can be considered the broad sense embodiment of the power supply control flow shown in Fig. 7 B.Wherein, the method includes step 1310～1340 as shown in the process flow diagram of Figure 13, being described as follows of each step: first, in step 1310, can utilize microcontroller to export the first control signal, first make the first lower voltage of voltage conversion circuit output, so that flow through, in the initial value of the 3rd electric current of light source, be less than the second electric current.Then, in step 1320, utilize this microcontroller to change gradually this first control signal, make this voltage conversion circuit heighten gradually this first voltage.In step 1330, when flowing through when the 3rd electric current oneself " being less than this second electric current " of this light source is transformed into " essence equals this second electric current ", the inventive method can utilize this microcontroller to read the current value of this first control signal at that time, and using this current value as the first optimal bias numerical value, and store this first optimal bias numerical value C bEST(the P point voltage in corresponding diagram 7A).In an embodiment, step 1330 may further include again following operation: this current value is added to error tolerance value and obtains the second optimal bias numerical value, and alternative this first optimal bias numerical value changes this second optimal bias numerical value of storage C bEST' (the Q point voltage in corresponding diagram 7A), wherein this error tolerance value can be controlled this first voltage raising direct current (DC) bias 0.5V～5V of this voltage conversion circuit output.Finally, among step 1340, can utilize this microcontroller with reference to this first optimal bias numerical value, to control this voltage conversion circuit, export this first voltage.
In another implementing procedure of the inventive method shown in Figure 14, before step 1310, include again step 1305, whether it detects user for this microcontroller and requires to proofread and correct, if not, can directly enter step 1335 by step 1305, directly read this first optimal bias numerical value C bEST(the P point voltage in corresponding diagram 7A), and in after enter step 1340, with reference to this first optimal bias numerical value, to control this voltage conversion circuit, export this first voltage.
In another implementing procedure of the inventive method shown in Figure 15, the inventive method more comprises step 1302, and whether it detects user for this microcontroller and require to proofread and correct, and if not, by step 1302, directly enters step 1332, reads this second optimal bias numerical value C bEST' (the Q point voltage in corresponding diagram 7A), and perform step 1340 after substituting this first optimal bias numerical value with this second optimal bias numerical value, with reference to this second optimal bias numerical value, to control this voltage conversion circuit, export this first voltage.
The fourth embodiment of the present invention separately provides a kind of display device, its Simple rack composition display device 2200 as shown in figure 16.Display device 2200 and display device 1100 differences are the quantity of driven light source.In the present embodiment, light source 2220_1～2220_N that display device 2200 comprises a plurality of parallel connections and drive and control by voltage conversion circuit 2230, target current circuit 2240, microcontroller 2250 and the formed loop of feedback loop 2260.Wherein, each light source 2220_1～2220_N may include one or more series connection light-emittingdiode.Similarly, circuit in display device 2200 must carry out stable Current Control to light source 2220_1～2220_N, except can maintain guarantee light source 2220_1～2220_N can stable maintenance in required brightness, also can guarantee that brightness between Different Light 2220_1～2220_N is evenly with consistent.Drive the power supply of each light source 2220_1～2220_N to be provided by voltage conversion circuit 2230, it is by external power source P aCbe converted to direct supply P dC, and utilize direct supply P dCdrive light source 2220_1～2220_N in parallel, wherein, direct supply P dCthere is the first voltage V 1.Target current circuit 2240 is coupled to light source 2220_1～2220_N, mainly light source 2220_1～2220_N is carried out determining Current Control, and voltage conversion circuit 2230 can provide direct supply P dCwhile carrying out driving light source 2220_1～2220_N, as the first voltage V 1while meeting specific size, target current circuit 2240 can biasedly enter default mode of operation, and then controls total electricity (that is the 3rd electric current I of flowing through on light source 2220_1～2220_N 3), make total electricity be equal in fact the second electric current I 2be multiplied by quantity N (that is the N*I of light source 2220_1～2220_N in parallel 2), now, the first voltage V no matter 1how to increase by the 3rd electric current I 3all the time be equal to the second electric current I 2.Microcontroller 2250, sees through target current circuit 2140, is also coupled to light source 2220_1～2220_N, and its major function is being controlled voltage conversion circuit 2230 by the mechanism of feedbacking, and it can reduce the first voltage V as far as possible 1magnitude of voltage, and simultaneously can keep biased this default mode of operation that enters of target current circuit 2140; So reduce the pressure drop on target current circuit 2140, reduce unnecessary power loss.
In order to determine the first voltage V 1optimum voltage value, can detecting the flow through electric current summation of light source 2220_1～2220_N of microcontroller 2250, the 3rd electric current I 3current value, and produce according to this first control signal S 1.When producing first, microcontroller 2250 controls signal S 1afterwards, being coupled to the feedback loop 2260 of voltage conversion circuit 2230 and microcontroller 2250 just can be based on the first control signal S 1control voltage conversion circuit 2130, to regulate the first voltage V 1.Because the machine-processed object of back coupling is moderately to adjust the first voltage V 1, avoid unnecessary power loss, and can keep again the Current Control of determining of light source 2220_1～2220_N (in other words, to make as far as possible to maintain the first voltage V simultaneously 1in lower permissible range).Therefore, the first voltage V 1magnitude of voltage must at least maintain corresponding the 3rd electric current I of electric current summation of the light source 2220_1～2220_N that can guarantee to flow through 3equal in fact the second electric current I 2, to meet the demand of determining Current Control.For asking stablizing on circuit operation, the first voltage V 1to be controlled in to be slightly larger than and " maintain the 3rd electric current I 3essence equals the second electric current I 2be multiplied by the quantity N of light source 2220_1～2220_N in parallel " required minimum voltage value.So, biased the entering in this default mode of operation of target current circuit 2240 energy also reduced the electric energy that target current circuit 2240 consumes simultaneously.Roughly, the mechanism of the Current Control in the present invention can see through microcontroller 2250 and regulate the first voltage V 1remain on optimum voltage value, determine target current Circuit tuning 2140 bias point, make target current Circuit tuning 2140 can carry out determining Current Control.
Be same as the explanation of Fig. 7 A and 7B, as the first voltage V 1continue to increase, until the 3rd electric current I 3target current value just with the second electric current I 2be multiplied by the value of N when suitable, after the first voltage V no matter 1how to increase by the 3rd electric current I 3value is maintained and is equal to the second electric current I 2state.Therefore, the present embodiment also can see through the method be same as described in previous the 3rd embodiment, sees through the first voltage V 1maintain the position of magnitude of voltage P or magnitude of voltage Q, make the 3rd electric current I 3with the second electric current I 2the value that is multiplied by N is identical in fact.
Due to the quantity of light source 2220_1～2220_N in the present embodiment and the quantity of previous embodiment different, so the framework of target current circuit 2240 and target current circuit 2140 also some elementary errors is different, please refer to Figure 17.As shown in the figure, light source 2220_1～2220_N will be respectively coupled to the electric crystal T2～T (N+1) of equal number, and the identical electric current I of flowing through respectively on it 31～I 3N, its sum total is the 3rd electric current I 3.Second electric current I of flowing through on electric crystal T1 2can change along with the pattern of viewing and admiring that user institute wish is used, and then through the mechanism of current mirror, adjust the electric current I of each light source 2220_1～2220_N 31～I 3N.Similarly, the present embodiment also available different principle and framework in Fig. 8～Figure 10 decide second electric current I of flowing through on electric crystal T1 2.Again, along with the signal form that 2250 of microcontrollers can be exported is different, the present embodiment also can adopt the enforcement aspect as shown in Figure 11 or Figure 12 to realize the first voltage V being produced for voltage conversion circuit 2230 1adjusting.
In addition the direct supply P that, voltage conversion circuit 2230 provides dCalso can carry out extra voltage transitions by reduction voltage circuit 2270, with by the first voltage V 1be reduced to second voltage V 2thereby, microcontroller 2250 is carried out to electric power supply.
It should be noted in the discussion above that above and mention different particular implementation aspects in the 3rd embodiment, and these embodiment also can be implemented in the 4th embodiment by milli without barrier.Please refer to Figure 18～Figure 20.As shown in figure 18, by variable resistor R, adjust the second electric current I 2size mode also may be implemented in target current circuit 2240, and by filtering circuit 2280 by the first signal S 1be converted to S 1'.In addition, feedback loop 2260 can be realized by the mode in figure, the first signal S1 ' after utilizing error amplifier A1 relatively to change with by the first voltage V 1the size of the dividing potential drop that samples and come, then control voltage conversion circuit 2230 by result relatively.Moreover, as shown in figure 19, adjust the second electric current I 2the object of size also can realize by the filtering circuit 2246 in target current circuit 2240, wherein, and in order to change the first signal S 1filtering circuit 2280 can be the low-pass filtering framework shown in figure.Moreover feedback loop 2260 ' can be that the mode of simplifying realizes compared to Figure 18.In addition, as shown in figure 20, under the situation of microcontroller 2250 exportable analog signals, the first signal S 1with the second signal S 2, can not need by other additional circuits carry out signal conversion, and directly export feedback loop 2260 to " with current mirror 2242.
Although above for different embodiment or when implementing aspect and being described, mentioned respectively the action of different architectural feature or method, but it should be noted in the discussion above that these different characteristics to see through suitable modification and be implemented in same specific embodiment simultaneously or implement in aspect.
Concept based on above fourth embodiment of the invention, another embodiment of the inventive method is described as follows.Only be the quantity of light source and relative current relationship with aforesaid embodiment difference.The present embodiment includes step 2410～2440 as shown in the process flow diagram of Figure 21, being described as follows of each step: first, in step 2410, can utilize microcontroller to export the first control signal, make the first lower voltage of voltage conversion circuit output, so that flow through, in the initial value of the 3rd electric current of the electric current summation of a plurality of light sources of parallel connection, be less than the quantity that the second electric current is multiplied by these a plurality of light sources in parallel.Then, in step 2420, utilize this microcontroller to change gradually this first control signal, make this voltage conversion circuit heighten gradually this first voltage.In step 2430, when the 3rd electric current of flowing through in the electric current summation of those light sources is when " being less than the quantity that this second electric current is multiplied by these a plurality of light sources in parallel " is transformed into " essence equals the quantity that this second electric current is multiplied by these a plurality of light sources in parallel ", the inventive method can utilize this microcontroller to read the current value of this first control signal at that time, and using this current value as the first optimal bias numerical value, and store this first optimal bias numerical value.In an embodiment, step 2430 may further include again following operation: this current value is added to error tolerance value and obtains the second optimal bias numerical value, and substitute this first optimal bias numerical value and change and store this second optimal bias numerical value, this first voltage that wherein this error tolerance value can be controlled this voltage conversion circuit output improves a direct current (DC) bias 0.5V～5V.Finally, among step 2440, can utilize this microcontroller with reference to this first optimal bias numerical value, to control this voltage conversion circuit, export this first voltage.Similarly, in another implementing procedure of the inventive method shown in Figure 22, before step 2410, include again step 2405, whether it detects user for this microcontroller and requires to proofread and correct, if not, can directly enter step 2435 by step 2405, directly read this first optimal bias numerical value, and in after enter step 2440, with reference to this first optimal bias numerical value, to control this voltage conversion circuit, export this first voltage.In another implementing procedure of the inventive method shown in Figure 23, the inventive method more comprises step 2402, whether it detects user for this microcontroller and requires to proofread and correct, if not, by step 2402, directly enter step 2432, read this second optimal bias numerical value, and perform step 2440 after substituting this first optimal bias numerical value with this second optimal bias numerical value, with reference to this first optimal bias numerical value, to control this voltage conversion circuit, export this first voltage.
Method of the present invention can specifically be implemented according to following mode, as: by processor, carry out a software, pass through pure hardware circuit, or by both combinations.In the middle of, processor may be general use or application specific processor, and this software comprises programmed logic, and instruction and data can realize the effect that the inventive method has when this software is performed.Wherein, this software can be stored in computer readable media, as read-only memory, and random access memory, disk drive, CD-ROM device, fast flash memory bank or any other possible numerical digit storing media.Moreover method effect of the present invention also can realize by including the pure hardware circuit of hardware wired logic (hard-wired logic).
In sum, the inventive method can provide suitable DC voltage to give light source accurately, making not have too much voltage can be expended on other circuit of connecting with light source, and, the present invention also can suitable adjusting be supplied to the DC voltage size of light source, and particularly, when light source is under relatively low operating current, the now pressure drop on light source is also lower comparatively speaking, therefore the present invention reduces voltage supply now, to reduce unnecessary power supply consume.Wherein, the present invention reaches identical technique effect by the mode of pure hardware circuit and the mode of microcontroller again.The mode of pure hardware circuit has the cost of less expensive, and the mode of microcontroller can more accurately be fitted the operation of light source and be adjusted supplied DC voltage.
The present invention is described by above-mentioned related embodiment, yet above-described embodiment is only for implementing example of the present invention.Must be pointed out that, the embodiment having disclosed does not limit the scope of the invention.On the contrary, the change done without departing from the spirit and scope of the present invention and retouching, all belong to scope of patent protection of the present invention.

Claims (30)

1. a display device, this display device comprises:
Light source;
Voltage conversion circuit, is converted to direct supply to drive this light source by external power source, and this direct supply is exported the first voltage;
Target current circuit, when this target current circuit is biased while entering default mode of operation, the magnitude of current and the second electric current that this target current circuit is controlled this light source of flowing through equate;
Microcontroller, is coupled to this light source, detects the value of the 3rd electric current of this light source of flowing through, and produces accordingly the first control signal; And
Feedback loop, be coupled to this voltage conversion circuit and this microcontroller, according to this first control signal, control this voltage conversion circuit and adjust this first voltage, make this first voltage be greater than " maintain the 3rd electric current and equal this second electric current " required minimum voltage value, biased the entering in this default mode of operation of this target current circuit energy like this, and reduce the electric energy that this target current circuit consumes.
2. display device as claimed in claim 1, wherein this lower first voltage is exported in this voltage conversion circuit starting point, so that the initial value of the 3rd electric current is less than this second electric current, and this microcontroller is detected the 3rd electric current initial value and is exported this first control signal to this voltage conversion circuit, heighten gradually this first voltage, until the 3rd electric current equals this second electric current.
3. display device as claimed in claim 2, wherein when the 3rd electric current equals this second electric current, this microcontroller reads the current value of this first control signal, and be stored in this microcontroller this current value as optimal bias numerical value, after this display device restarts, this microcontroller can directly read this optimal bias numerical value and control this voltage conversion circuit and export this first voltage.
4. display device as claimed in claim 2, wherein when the 3rd electric current equals this second electric current, this microcontroller reads the current value of this first control signal, and this current value is added to error tolerance value and obtain optimal bias numerical value and be stored in this microcontroller, after this display device restarts, this microcontroller can directly read this optimal bias numerical value and control this voltage conversion circuit and export this first voltage.
5. display device as claimed in claim 4, wherein this optimal bias numerical value improves a direct current (DC) bias 0.5V～5V in order to control this first voltage of this voltage conversion circuit output.
6. display device as claimed in claim 1, wherein this target current circuit more comprises:
Resistance, in order to determine the size of this second electric current; And
Current mirror, this current mirror includes the first electric crystal and at least one the second electric crystal, and wherein this first electric crystal is coupled to this resistance, and this second electric crystal is coupled to this light source, this second electric current this first electric crystal of flowing through, the 3rd electric current this second electric crystal of flowing through.
7. display device as claimed in claim 1, wherein this microcontroller is more coupled to this target current circuit, according to user's input signal, produces accordingly second of digital form and controls signal and control this target current circuit, and this target current circuit more comprises:
D/A converting circuit, second controls the size that signal determines this second electric current according to this; And
Current mirror, this current mirror includes the first electric crystal and at least one the second electric crystal, and wherein this first electric crystal is coupled to this D/A converting circuit, and this second electric crystal is coupled to this light source, this second electric current this first electric crystal of flowing through, the 3rd electric current this second electric crystal of flowing through.
8. display device as claimed in claim 1, wherein this microcontroller is more coupled to this target current circuit, according to user's input signal, the second control signal that produces accordingly pulse width modulation (PWM) form is controlled this target current circuit, and this target current circuit more comprises:
Filtering circuit, second controls the size that signal determines this second electric current according to this; And
Current mirror, this current mirror includes the first electric crystal and at least one the second electric crystal, and wherein this first electric crystal is coupled to this filtering circuit, and this second electric crystal is coupled to this light source, this second electric current this first electric crystal of flowing through, the 3rd electric current this second electric crystal of flowing through.
9. display device as claimed in claim 1, more comprise reduction voltage circuit, be coupled between this voltage conversion circuit and this microcontroller, this reduction voltage circuit is in order to be second voltage by this first lower voltage, and wherein this second voltage is in order to for should the required electric energy of microcontroller; Wherein with respect to this voltage conversion circuit, export this different first voltage, this reduction voltage circuit maintains this fixing second voltage output.
10. display device as claimed in claim 1, wherein this first control signal is the control signal of pulse width modulation form, and this display device separately includes: filtering circuit, be coupled between this microcontroller and this voltage conversion circuit, in order to this first control signal is carried out to filtering processing, to produce filtered this first control signal, control this voltage conversion circuit.
11. display device as claimed in claim 1, the control signal that wherein this first control signal is digital form, and this display device separately includes: digital to analog converter, be coupled between this microcontroller and this voltage conversion circuit, in order to this first control signal is carried out to conversion process, with this first control signal producing after conversion, control this voltage conversion circuit.
12. 1 kinds of display device, this display device comprises:
A plurality of light sources in parallel;
Voltage conversion circuit, is converted to direct supply to drive this plurality of light sources in parallel by external power source, and this direct supply is exported the first voltage;
Target current circuit, when this target current circuit is biased while entering default mode of operation, the magnitude of current and the second electric current that this target current circuit is controlled each light source in these a plurality of light sources in parallel of flowing through equate;
Microcontroller, is coupled to this light source, detects the value of corresponding the 3rd electric current of this plurality of source current amount summation in parallel of flowing through, and produces accordingly the first control signal; And
Feedback loop, be coupled to this voltage conversion circuit and this microcontroller, according to this first control signal, control this voltage conversion circuit and adjust this first voltage, make this first voltage be greater than " maintain the 3rd electric current and equal the quantity that this second electric current is multiplied by these a plurality of light sources in parallel " required minimum voltage value, biased the entering in this default mode of operation of this target current circuit energy like this, and reduce the electric energy that this target current circuit consumes.
13. display device as claimed in claim 12, wherein this lower first voltage is exported in this voltage conversion circuit starting point, the initial value of the 3rd electric current is less than " this second electric current is multiplied by the quantity of these a plurality of light sources in parallel ", and this microcontroller is detected the 3rd electric current initial value and is exported this first control signal to this voltage conversion circuit, heighten gradually this first voltage, until the 3rd electric current equals " quantity that this second electric current is multiplied by these a plurality of light sources in parallel ".
14. display device as claimed in claim 13, wherein when the 3rd electric current equals " quantity that this second electric current is multiplied by these a plurality of light sources in parallel ", this microcontroller reads the current value of this first control signal, and be stored in this microcontroller this current value as optimal bias numerical value, after this display device restarts, this microcontroller can directly read this optimal bias numerical value and control this voltage conversion circuit and export this first voltage.
15. display device as claimed in claim 13, wherein when the 3rd electric current equals " quantity that this second electric current is multiplied by these a plurality of light sources in parallel ", this microcontroller reads this and first controls the current value of signal and add error tolerance value and obtain optimal bias numerical value, this optimal bias numerical value is stored in this microcontroller, after this display device restarts, this microcontroller can directly read this optimal bias numerical value and control this voltage conversion circuit and export this first voltage.
16. display device as claimed in claim 15, wherein this optimal bias numerical value improves direct current (DC) bias 0.5V～5V in order to control this first voltage of this voltage conversion circuit output.
17. display device as claimed in claim 12, wherein this target current circuit more comprises:
Resistance, in order to determine the size of this second electric current; And
Current mirror, this current mirror includes the first electric crystal and a plurality of the second electric crystals to should quantity of light source in parallel, wherein this first electric crystal is coupled to this resistance, each this second electric crystal is coupled to this parallel connection light source separately one to one, this second electric current this first electric crystal of flowing through, the flow through summation of these a plurality of the second electric crystal electric currents of the 3rd electric current.
18. display device as claimed in claim 12, wherein this microcontroller is more coupled to this target current circuit, and according to user's input signal, the second control signal that produces accordingly digital form is controlled this target current circuit; This target current circuit more comprises:
D/A converting circuit, second controls the size that signal determines this second electric current according to this; With
Current mirror, this current mirror includes the first electric crystal and a plurality of the second electric crystals to should quantity of light source in parallel, wherein this first electric crystal is coupled to this D/A converting circuit, each this second electric crystal is coupled to this parallel connection light source separately one to one, this second electric current this first electric crystal of flowing through, the flow through summation of these a plurality of the second electric crystal electric currents of the 3rd electric current.
19. display device as claimed in claim 12, wherein this microcontroller is more coupled to this target current circuit, and according to user's input signal, the second control signal that produces accordingly pulse width modulation form is controlled this target current circuit; This target current circuit more comprises:
Filtering circuit, second controls the size that signal determines this second electric current according to this; With
Current mirror, this current mirror includes the first electric crystal and a plurality of the second electric crystals to should quantity of light source in parallel, wherein this first electric crystal is coupled to this filtering circuit, each this second electric crystal is coupled to this parallel connection light source separately one to one, this second electric current this first electric crystal of flowing through, the flow through summation of these a plurality of the second electric crystal electric currents of the 3rd electric current.
20. display device as claimed in claim 12, more comprise reduction voltage circuit, be coupled between this voltage conversion circuit and this microcontroller, this reduction voltage circuit is in order to be second voltage by this first lower voltage, and wherein this second voltage is in order to for should the required electric energy of microcontroller; Wherein with respect to this voltage conversion circuit, export this different first voltage, this reduction voltage circuit maintains this fixing second voltage output.
21. display device as claimed in claim 12, wherein this first control signal is the control signal of pulse width modulation form, and this display device includes: filtering circuit, be coupled between this microcontroller and this voltage conversion circuit, in order to this first control signal is carried out to filtering processing, to produce filtered this first control signal, control this voltage conversion circuit.
22. display device as claimed in claim 12, the control signal that wherein this first control signal is digital form, and this display device separately includes: digital to analog converter, be coupled between this microcontroller and this voltage conversion circuit, in order to this first control signal is carried out to conversion process, with this first control signal producing after a conversion, control this voltage conversion circuit.
23. 1 kinds determine internal circuit working bias voltage method for display device, and wherein this display device comprises: light source; Voltage conversion circuit, is converted to direct supply to drive this light source by external power source, and this direct supply is exported the first voltage; Target current circuit, when this target current circuit is biased while entering default mode of operation, the magnitude of current and the second electric current that this target current circuit is controlled this light source of flowing through equate; Microcontroller, is coupled to this light source, detects the value of the 3rd electric current of this light source of flowing through, and produces accordingly the first control signal; And feedback loop, be coupled to this voltage conversion circuit and this microcontroller, according to this first control signal, control this voltage conversion circuit and adjust this first voltage; The method comprises step:
(1) utilize this microcontroller to export this first control signal, first make this lower first voltage of this voltage conversion circuit output, so that the initial value of the 3rd electric current is less than this second electric current;
(2) utilize this microcontroller to change gradually this first control signal, make this voltage conversion circuit heighten gradually this first voltage;
(3) when the 3rd electric current is when " being less than this second electric current " is transformed into " equaling this second electric current ", utilize this microcontroller to read the current value of this first control signal at that time, using this current value as the first optimal bias numerical value, and store this first optimal bias numerical value;
(4) utilize this microcontroller with reference to this first optimal bias numerical value, to control this voltage conversion circuit, export this first voltage.
24. methods as claimed in claim 23, step (3) further comprises: this current value is added to error tolerance value and obtains the second optimal bias numerical value, and alternative this first optimal bias numerical value changes this second optimal bias numerical value of storage, this first voltage raising direct current (DC) bias 0.5V～5V that wherein this error tolerance value is exported in order to control this voltage conversion circuit.
25. methods as claimed in claim 23, more comprise step: in step (1) before, whether this microcontroller detecting user requires to proofread and correct, if not, this microcontroller skips steps (1) (2) (3), directly read this first optimal bias numerical value, and execution step (4).
26. methods as claimed in claim 24, more comprise step: in step (1) before, whether this microcontroller detecting user requires to proofread and correct, if not, this microcontroller skips steps (1) (2) (3), directly read this second optimal bias numerical value, and perform step (4) after substituting this first optimal bias numerical value with this second optimal bias numerical value.
27. 1 kinds determine internal circuit working bias voltage method for display device, and this display device comprises: a plurality of light sources in parallel; Voltage conversion circuit, is converted to direct supply to drive this plurality of light sources in parallel by external power source, and this direct supply is exported the first voltage; Target current circuit, when this target current circuit is biased while entering default mode of operation, the magnitude of current and the second electric current that this target current circuit is controlled each light source in these a plurality of light sources in parallel of flowing through equate; Microcontroller, is coupled to this parallel connection light source, detects the value of the 3rd electric current of these a plurality of source current amount summations in parallel of flowing through, and produces accordingly the first control signal; And feedback loop, be coupled to this voltage conversion circuit and this microcontroller, according to this first control signal, control this voltage conversion circuit and adjust this first voltage; The method comprises step:
(1) utilize this microcontroller to export this first control signal, first make this lower first voltage of this voltage conversion circuit output, the initial value of the 3rd electric current is less than " this second electric current is multiplied by the quantity of these a plurality of light sources in parallel ";
(2) utilize this microcontroller to change gradually this first control signal, make this voltage conversion circuit heighten gradually this first voltage;
(3) when the 3rd electric current is when " being less than the quantity that this second electric current is multiplied by these a plurality of light sources in parallel " is transformed into " equaling the quantity that this second electric current is multiplied by these a plurality of light sources in parallel ", utilize this microcontroller to read the current value of this first control signal, using this current value as the first optimal bias numerical value, and store this first optimal bias numerical value;
(4) utilize this microcontroller with reference to this first optimal bias numerical value, to control this voltage conversion circuit, export this first voltage.
28. methods as claimed in claim 27, the method step (3) more comprises: this current value is added to error tolerance value and obtains the second optimal bias numerical value, and store this second optimal bias numerical value; Utilize this microcontroller with reference to this second optimal bias numerical value, control this voltage conversion circuit and export this first voltage, wherein this error tolerance value improves direct current (DC) bias 0.5V～5V in order to control this first voltage of this voltage conversion circuit output.
29. methods as claimed in claim 27, more comprise step: in step (1) before, whether this microcontroller detecting user requires to proofread and correct, if not, this microcontroller skips steps (1) (2) (3), directly read this first optimal bias numerical value, and execution step (4).
30. methods as claimed in claim 28, more comprise step: in step (1) before, whether this microcontroller detecting user requires to proofread and correct, if not, this microcontroller skips steps (1) (2) (3), directly read this second optimal bias numerical value, and perform step (4) after substituting this first optimal bias numerical value with this second optimal bias numerical value.
CN201310089281.8A 2013-03-19 2013-03-19 Display device and method for display device to determine internal circuit operating bias Pending CN103646633A (en)

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Application publication date: 20140319