CN101621876B - Luminous element drive circuit and method thereof - Google Patents
Luminous element drive circuit and method thereof Download PDFInfo
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- CN101621876B CN101621876B CN2008101319555A CN200810131955A CN101621876B CN 101621876 B CN101621876 B CN 101621876B CN 2008101319555 A CN2008101319555 A CN 2008101319555A CN 200810131955 A CN200810131955 A CN 200810131955A CN 101621876 B CN101621876 B CN 101621876B
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
A luminous element drive circuit and a method thereof are disclosed. One end of the luminous element is coupled to a power voltage and the cathode of a diode by an inductor, and the other end thereof is coupled to the anode of the diode. The luminous element drive circuit comprises a switch, a current sensing circuit and a switch control circuit. The current sensing circuit is coupled to the anode of the diode by the switch and used for deciding whether to generate closing control signals according to the breakover current value of the switch. The switch control circuit is used for controlling the breakover and closing of the switch and can close the switch according to the closing control signals. In addition, the switch control circuit is also used for comparing the breakover current value of the switch with a reference current value, so as to generate comparison result to dynamically adjust the time length for closing the switch.
Description
Technical field
The present invention relates to a kind of drive circuit and method thereof, and particularly relate to a kind of light emitting element driving circuit and method thereof.
Background technology
Fig. 1 shows traditional LED driving circuit and the coupling mode thereof of carrying out the step-down pattern (buck type) of current sense at the source electrode of MOS transistor.This light-emitting diode (light emittingdiode, LED) the SR latch 204 that triggered by timing sequence generating circuit 202, positive edge of drive circuit, is formed the light-emitting diode string 212 that is formed by a plurality of light-emitting diodes in order to driving with door 206, switch 208 and the current sensing circuit 210 realized with NMOS (N-type metal oxide semiconductor) transistor.Certainly, above-mentioned switch 208 also can be by PMOS (P-type metal oxidesemiconductor) transistor or bipolar junction transistor (bipolar junction transistor, BJT) ... wait the transistor of other pattern to form.In Fig. 1, an end of light-emitting diode string 212 is coupled to the supply voltage VIN of direct current pattern and the negative electrode of diode 216 by inductance 214, and the other end of light-emitting diode string 212 then is coupled to the anode of diode 216.
Timing sequence generating circuit 202 is in order to producing conducting control signal TS, and changes the sequential of conducting control signal TS according to sequencing control signal EXCS, and current sensing circuit 210 is then according to the On current I of switch 208
DRAINValue determine whether producing closing control signals RS.Thus, SR latch 204 just can arrange by it holds S and replacement end R to receive respectively conducting control signal TS and closing control signals RS, and change the output of output Q according to these two signals, with by coming control switch 208 conductings with door 206 or close, and then control inductive current I
LSize.Represent the light modulation signal of PWM (pulse width modulation) form as for DIM shown in Figure 1, in order to the brightness of adjusting the light source that light-emitting diode string 212 sends and whether determine closing switch 208.
Fig. 2 is the inductive current I of circuit shown in Figure 1
LAnd On current I
DRAINOscillogram.Please merge with reference to Fig. 1 and Fig. 2, by these two accompanying drawings as can be known, as On current I
DRAINReach the peak I of setting
DMAXThe time, switch 208 just can be closed, until just once again conducting after the elapsed time T, such operation is so that inductive current I
LAt lowest high-current value I
MAXWith minimum current value I
MINBetween change, and then allow the brightness of light-emitting diode string 212 be stablized.Because when switch 208 cuts out, current sensing circuit 210 just can't sense electric current, so traditional LED driving circuit need to use timing sequence generating circuit 202 regularly provide SR latch 204 required signal is set, with the discharge time of further control inductance 214.
Yet because timing sequence generating circuit 202 relies on the sequential that sequencing control signal EXCS changes conducting control signal TS, therefore the excursion as inductive current IL surpasses lowest high-current value I
MAXWith minimum current value I
MINThe scope that defines and when need changing the sequential of conducting control signal TS, the user just must revise the circuit that sequencing control signal EXCS is provided and change sequencing control signal EXCS, otherwise just must change the inductance value of inductance 214, also or the light-emitting diode number that changes light-emitting diode string 212 just can reach the inconvenience that causes the user to use.And if LED driving circuit is made into circuit chip, extra pin (pin) also must be arranged to couple the external circuit that sequencing control signal EXCS is provided, cause equally the puzzlement in the design.
Summary of the invention
The invention provides a kind of light emitting element driving circuit, it can make inductive current I
LAutomatically at lowest high-current value I
MAXWith minimum current value I
MINBetween lock operation.
The present invention also provides a kind of light emitting element driving method, and it can make inductive current I
LAutomatically at lowest high-current value I
MAXWith minimum current value I
MINBetween lock operation.
The invention provides a kind of light emitting element driving circuit, be suitable for driving light-emitting component, wherein an end of light-emitting component is coupled to the negative electrode of supply voltage and a diode by inductance, and the other end of light-emitting component then couples the anode of above-mentioned diode.This light emitting element driving circuit includes switch, current sensing circuit and ON-OFF control circuit.Above-mentioned switch has first end, the second end and control end, and the first end of this switch couples the other end of light-emitting component.Current sensing circuit couples the second end of switch, and determines whether to produce closing control signals according to the electric conduction flow valuve of switch.ON-OFF control circuit couples control end and second end of current sensing circuit and switch, in order to the conducting of control switch with close, and ON-OFF control circuit can compare electric conduction flow valuve and the reference current value of switch when actuating switch, to produce comparative result, and close above-mentioned switch according to closing control signals, and dynamically adjust the time span of closing above-mentioned switch according to comparative result.
The present invention also provides a kind of light emitting element driving circuit, is suitable for driving light-emitting component, and wherein an end of light-emitting component is coupled to the negative electrode of supply voltage and a diode, and the other end of light-emitting component then couples the anode of above-mentioned diode by inductance.As for this light emitting element driving circuit, its member is then identical with the aforementioned light emitting element driving circuit that provides.
The present invention provides again a kind of light emitting element driving method, wherein an end of light-emitting component is coupled to the negative electrode of supply voltage and a diode by inductance, the other end of light-emitting component then couples the anode of above-mentioned diode and the first end of a switch, and the second end of this switch couples common electric potential.Described light emitting element driving method includes the following step: one, provide signal to the control end of above-mentioned switch, with the conducting of control switch with close.Its two, determine whether close this switch by above-mentioned signal according to the electric conduction flow valuve of switch.Its three, relatively electric conduction flow valuve and the reference current value of switch when actuating switch producing comparative result, and are dynamically adjusted the time span of closing above-mentioned switch according to comparative result by above-mentioned signal.
The present invention provides a kind of light emitting element driving method again, wherein an end of light-emitting component is coupled to the negative electrode of supply voltage and a diode, the other end of light-emitting component then couples the anode of above-mentioned diode and the first end of a switch by inductance, and the second end of this switch couples common electric potential.This light emitting element driving method is identical with the aforementioned light emitting element driving method that provides.
In an embodiment of light emitting element driving circuit, above-mentioned ON-OFF control circuit includes sequential control circuit and SR latch.Sequential control circuit couples control end and second end of switch, controls signal in order to produce conducting, and compare electric conduction flow valuve and the reference current value of switch when switch conduction, with the generation comparative result, and dynamically adjusts according to this output time that signal is controlled in conducting.End being set and resetting to hold of SR latch receives respectively conducting control signal and closing control signals, and the output of SR latch then couples the control end of switch.
In an embodiment of light emitting element driving circuit, above-mentioned sequential control circuit includes comparison circuit and adaptability timing sequence generating circuit.Comparison circuit couples control end and second end of switch, in order to relatively electric conduction flow valuve and the reference current value of switch when the switch conduction, to produce above-mentioned comparative result.The adaptability timing sequence generating circuit couples the control end of switch, controls signal in order to produce conducting, and dynamically adjusts the output time of conducting control signal when switch conduction according to comparative result.
In an embodiment of light emitting element driving circuit, above-mentioned comparison circuit includes comparator.One input of this comparator receives reference current value, and another input couples the second end of switch, and this comparator determines that according to the voltage swing of the control end of switch the signal that whether two input is received compares, to produce comparative result.
In an embodiment of light emitting element driving circuit, above-mentioned adaptability timing sequence generating circuit includes sequential andlogic control circuit, charge pump, low pass filter and Voltage-time conversion device.Sequential andlogic control circuit determines whether operate according to the voltage swing of the control end of switch, and when operating, increases the control signal or reduce the control signal according to comparative result output.Charge pump has the electric current feed end, and receives when increasing the control signal just from electric current feed end output current when charge pump, and just draws electric current from the electric current feed end when charge pump receives to reduce when controlling signal.Low pass filter coupled electric current feed end, and according to the generation of the sense of current on electric current feed end control voltage.The Voltage-time conversion device couples low pass filter, controls signal in order to export above-mentioned conducting, and dynamically adjusts the output time of conducting control signal according to control voltage.
In an embodiment of light emitting element driving circuit and light emitting element driving method, above-mentioned reference current value is the minimum current value of above-mentioned inductance.
The present invention adopts special sequential control circuit to make ON-OFF control circuit in the light emitting element driving circuit, so that this ON-OFF control circuit is except the closing control signals closing switch that meeting is exported according to current sensing circuit, electric conduction flow valuve and the reference current value that also can when actuating switch, compare switch, with the generation comparative result, and dynamically adjust according to this time span of closing above-mentioned switch.Accordingly, just can make inductive current I
LThe value automatic lock on ground fix on a preset range.
For above-mentioned feature and advantage of the present invention can be become apparent, preferred embodiment cited below particularly, and be described with reference to the accompanying drawings as follows.
Description of drawings
Fig. 1 shows traditional LED driving circuit and the coupling mode thereof of carrying out the step-down pattern of current sense at the source electrode of MOS transistor.
Fig. 2 is the electric current I of circuit shown in Figure 1
LAnd I
DRAINOscillogram.
Fig. 3 is according to the light emitting element driving circuit of one embodiment of the invention and coupling mode thereof.
Fig. 4 shows according to the comparison circuit 340 of one embodiment of the invention and the implementation of adaptability timing sequence generating circuit 350.
Fig. 5 shows the inductive current I of Fig. 3
LOn current I with switch 400
DRAIN, and the increase of Fig. 4 control signal ICS and the oscillogram that reduces control signal DCS.
Fig. 6 is the flow chart of steps according to the light emitting element driving method of one embodiment of the invention.
The reference numeral explanation
202: timing sequence generating circuit
204,320:SR latch
206,310: with door
208,400: switch
210,500: current sensing circuit
212: the light-emitting diode string
214,700: inductance
216,800: diode
300: ON-OFF control circuit
330: sequential control circuit
340: comparison circuit
341: comparator
350: the adaptability timing sequence generating circuit
351: sequential andlogic control circuit
352: charge pump
353,354: controlled current source
355: the electric current feed end
356: low pass filter
357: electric capacity
358: the Voltage-time conversion device
600: light-emitting component
CRS: comparative result
DCS: reduce the control signal
DIM: light modulation signal
EXCS: sequencing control signal
GND: common electric potential
ICS: increase the control signal
IDRAIN: On current
I
L: inductive current
IREF: reference current value
RS: closing control signals
S602-S606: step
TS, CS: conducting control signal
VC: control voltage
VG: control end voltage
VIN: supply voltage
VS: voltage signal
Embodiment
Fig. 3 is according to the light emitting element driving circuit of one embodiment of the invention and coupling mode thereof.This light emitting element driving circuit is comprised of ON-OFF control circuit 300, switch 400 and current sensing circuit 500, in order to drive light-emitting component 600.Wherein, an end of light-emitting component 600 couples the negative electrode of supply voltage VIN and diode 800 by inductance 700, and the other end of light-emitting component 600 then is coupled to the anode of diode 800.In this example, light-emitting component 600 is comprised of the light-emitting diode of a plurality of series connection, and supply voltage VIN is direct voltage, realizes with nmos pass transistor as for 400 on switch.Certainly, this switch 400 also can be by PMOS transistor or bipolar junction transistor ... wait the transistor of other pattern to form.
The first end of switch 400 couples the other end of light-emitting component 600.Current sensing circuit 500 couples the second end of switch 400, and (is On current I according to the electric conduction flow valuve of switch 400
DRAINValue) determine whether to produce closing control signals RS.ON-OFF control circuit 300 couples control end and second end of current sensing circuit 500 and switch 400, in order to the conducting of control switch 400 with close, and ON-OFF control circuit 300 can compare electric conduction flow valuve and the reference current value IREF of switch 400 when actuating switch 400, to produce comparative result CRS, and according to closing control signals RS closing switch 400, and the time span of dynamically adjusting closing switch 400 according to comparative result CRS.In this example, reference current value IREF is the minimum current value of inductance 700.
ON-OFF control circuit 300 includes and door 310, SR latch 320 and sequential control circuit 330.Sequential control circuit 330 couples control end and second end of switch 400, in order to produce conducting control signal CS, and when switch 400 conducting relatively electric conduction flow valuve and the reference current value IREF of switch 400, with generation comparative result CRS, and dynamically adjust according to this output time that signal CS is controlled in conducting.Arranging of SR latch 320 holds S and replacement end R to receive respectively conducting control signal CS and closing control signals RS.Couple respectively the output Q of a light modulation signal DIM and SR latch 320 with two inputs of door 310, then couple the control end of switch 400 with the output of door 310.In this example, SR latch 320 is positive edge activation patterns, and the light modulation signal can be realized with the PWM signal.
It is worth mentioning that, although in this example, listed a kind of form of the coupling mode of light-emitting component 600 and inductance 700, yet such coupling mode is not to limit the present invention.Mutually exchange even it will be appreciated by those skilled in the art that the position of above-mentioned two members, as long as the anode of all light-emitting diodes all is connected in series towards supply voltage VIN in the light-emitting component 600, also can implement.In addition, in this example, current sensing circuit 500 can be implemented with resistance circuit simply, above-mentioned closing control signals RS to be provided and to be proportional to the voltage signal VS of the electric conduction flow valuve of switch 400.Thus, comparison circuit 340 just can adopt general comparator to realize, as shown in Figure 4.
Fig. 4 shows according to the comparison circuit 340 of one embodiment of the invention and the implementation of adaptability timing sequence generating circuit 350.As shown in Figure 4, comparison circuit 340 comprises comparator 341.One input of comparator 341 receives the reference current value IREF that is modeled into a voltage, this voltage is directly proportional with reference current value IREF, and another input couples the second end of switch 400, couple mutually the voltage signal VS at place with receiving key 400 and current sensing circuit 500, and comparator 341 determines that according to the size of the control end voltage VG of switch 400 signal that whether two input is received compares, to produce comparative result CRS.
Adaptability timing sequence generating circuit 350 includes sequential andlogic control circuit 351, charge pump 352, low pass filter 356 and Voltage-time conversion device 358.Sequential andlogic control circuit 351 determines whether operate according to the size of the control end voltage VG of switch 400, and when operating, increases control signal ICS or reduce control signal DCS according to comparative result CRS output.Charge pump 352 has electric current feed end 355, and just supplies induced current to electric current feed end 355 when charge pump 352 receives increase control signal ICS, and just draws electric current from electric current feed end 355 when receiving minimizing control signal DCS.Low pass filter 356 couples electric current feed end 355, and produces control voltage VC according to the sense of current on the electric current feed end 355.Voltage-time conversion device 358 couples low pass filter 357, controls signal CS in order to export conducting, and the output time of signal CS is controlled in the dynamic adjustment of the size conducting of foundation control voltage VC.
Fig. 5 shows the inductive current I of Fig. 3
LOn current I with switch 400
DRAIN, and the increase of Fig. 4 control signal ICS and the oscillogram that reduces control signal DCS.Please be simultaneously with reference to Fig. 4 and Fig. 5, when comparator 341 judges that the control end voltage VG of switch 400 transfers high potential (high) to by electronegative potential (low), comparator 341 is the size of comparative voltage signal VS and the voltage that is modeled to by reference current value IREF just, and this operation is just as in On current I relatively
DRAINAnd both sizes of reference current value IREF.If the value that comparator 341 is judged voltage signal VS is during greater than the value of the voltage that is modeled to by reference current value IREF, the inductive current I in the expression one-period
LMinimum greater than the minimum current value I that sets
MINSo sequential andlogic control circuit 351 is just exported increases control signal ICS; Otherwise, then represent the inductive current I in the one-period
LMinimum less than the minimum current value I that sets
MINSo sequential andlogic control circuit 351 is just exported and reduced control signal DCS, each pulse that wherein increases control signal ICS and minimizing control signal DCS has a set time width.
When controlled current source 353 receives increase control signal ICS, just provide current to electric current feed end 355, so that control voltage VC rising, and when controlled current source 354 receives minimizing control signal DCS, just draw electric current from electric current feed end 355, so that control voltage VC descends.Accordingly, Voltage-time conversion device 358 just can dynamically be adjusted according to the size of control voltage VC the output time of conducting control signal CS, with by SR latch 320 with come the length of the shut-in time of control switch 400 with door 310, this can be found out by the time T 1 among Fig. 5, T2, T3....Saying expressly, is exactly the inductive current I in one-period
LMinimum greater than minimum current value I
MINThe time just prolong shut-in time of switch 400, and the inductive current I in one-period
LMinimum less than minimum current value I
MINThe time just shorten shut-in time of switch 400.If T1 is the given time at the beginning of the circuit operation, it can be at random reasonable value so.Certainly, at the initial stage of ON-OFF control circuit 300 runnings, the shut-in time of switch 400 can constantly be adjusted, yet just can tend towards stability after after a while, thus, and inductive current I
LBut value just automatic lock on ground fix on lowest high-current value I
MAXWith minimum current value I
MINBetween.In addition, should be noted the I among Fig. 5
DMAXEqual I
MAX
Although in the above-described embodiments, current sensing circuit 500 is coupled between switch 400 and the common electric potential GND, to carry out the operation of current sense, yet such sensing mode is not to limit the present invention, even those skilled in the art are when knowing that the second end of switch 400 directly couples common electric potential GND, also still can come current sensor with other mode.In addition, it is worth mentioning that, if light emitting element driving circuit without the need for the function of light modulation, just do not need and door 310 and light modulation signal DIM, as long as the control end that the output Q of SR latch 320 is directly coupled switch 400 just can.
Teaching by above-described embodiment, can summarize a kind of light emitting element driving method, wherein an end of light-emitting component is coupled to the negative electrode of supply voltage and diode by inductance, the other end of light-emitting component then couples the anode of diode and the first end of switch, and the second end of switch couples common electric potential.Fig. 6 is the flow chart of steps according to the light emitting element driving method of one embodiment of the invention.Please refer to Fig. 6, this light emitting element driving method includes the following step: one, the control end of signal to switch is provided, with the conducting of control switch with close (shown in step S602).Its two, determine whether close above-mentioned switch (shown in step S604) by above-mentioned signal according to the electric conduction flow valuve of switch.Its three, relatively electric conduction flow valuve and the reference current value of switch when actuating switch producing comparative result, and are dynamically adjusted the time span (shown in step S606) of closing above-mentioned switch according to comparative result by above-mentioned signal.Certainly, as aforementioned, both positions of light-emitting component and inductance also can be exchanged mutually, can't affect the mode of operation.
In sum, the present invention adopts special sequential control circuit to make ON-OFF control circuit in the light emitting element driving circuit, so that this ON-OFF control circuit is except the closing control signals closing switch that meeting is exported according to current sensing circuit, electric conduction flow valuve and the reference current value that also can when actuating switch, compare switch, with the generation comparative result, and dynamically adjust according to this time span of closing above-mentioned switch.Accordingly, just can make inductive current I
LThe value automatic lock on ground fix on a preset range.In addition, if light emitting element driving circuit of the present invention is made into circuit chip, also needn't design extra pin.
Although the present invention discloses as above with preferred embodiment; but it is not to limit the present invention, those skilled in the art, under the premise without departing from the spirit and scope of the present invention; when can doing some changes and modification, so protection scope of the present invention should be as the criterion with claim of the present invention.
Claims (13)
1. light emitting element driving circuit, be suitable for driving a light-emitting component, wherein an end of this light-emitting component is coupled to the negative electrode of a supply voltage and a diode by an inductance, and the other end of this light-emitting component then couples the anode of this diode, and this light emitting element driving circuit comprises:
One switch has first end, the second end and control end, and the first end of this switch couples the other end of this light-emitting component;
One current sensing circuit couples the second end of this switch, and determines whether to produce a closing control signals according to the electric conduction flow valuve of this switch; And
One ON-OFF control circuit, couple control end and second end of this current sensing circuit and this switch, in order to the conducting of controlling this switch with close, and this ON-OFF control circuit relatively electric conduction flow valuve and reference current value of this switch when this switch of conducting, to produce a comparative result, and close this switch according to this closing control signals, and dynamically adjust the time span of closing this switch according to this comparative result.
2. light emitting element driving circuit as claimed in claim 1, wherein this ON-OFF control circuit comprises:
One sequential control circuit, couple control end and second end of this switch, in order to producing conducting control signal, and when this switch conduction relatively the electric conduction flow valuve of this switch and this reference current value, producing this comparative result, and dynamically adjust according to this output time of this conducting control signal; And
One SR latch, have end is set, reset end and output, this SR latch end is set and the end of resetting receives respectively this conducting control signal and this closing control signals, the output of this SR latch then couples the control end of this switch.
3. light emitting element driving circuit as claimed in claim 2, wherein this sequential control circuit comprises:
One comparison circuit, wherein this sequential control circuit couples control end and second end of this switch via this comparison circuit, in order to relatively electric conduction flow valuve and this reference current value of this switch when this switch conduction, to produce this comparative result; And
One adaptability timing sequence generating circuit couples this comparison circuit, controls signal in order to receive this comparative result and to produce this conducting, and dynamically adjusts the output time of this conducting control signal when this switch conduction according to this comparative result.
4. light emitting element driving circuit as claimed in claim 3, wherein this comparison circuit comprises:
One comparator, one input of this comparator receives this reference current value, and another input couples the second end of this switch, and this comparator determines that according to the voltage swing of the control end of this switch the signal that whether two input is received compares, to produce this comparative result.
5. light emitting element driving circuit as claimed in claim 3, wherein this adaptability timing sequence generating circuit comprises:
One sequential andlogic control circuit determines whether operate according to the voltage swing of the control end of this switch, and when operating, increases control signal or according to this comparative result output one and reduce the control signal;
One charge pump has an electric current feed end, and when this charge pump receives this increase control signal just from this electric current feed end output current, and just draw electric current from this electric current feed end when this charge pump receives when signal is controlled in this minimizing;
One low pass filter couples this electric current feed end, and produces a control voltage according to the sense of current on this electric current feed end; And
One Voltage-time conversion device couples this low pass filter, controls signal in order to export this conducting, and dynamically adjusts the output time of this conducting control signal according to this control voltage.
6. light emitting element driving circuit as claimed in claim 2, wherein this ON-OFF control circuit also comprises:
One with door, should couple respectively the output of a light modulation signal and this SR latch with two inputs of door, should then couple with the output of door the control end of this switch.
7. light emitting element driving circuit as claimed in claim 1, wherein this light-emitting component is comprised of the light-emitting diode of a plurality of series connection, and this supply voltage is direct voltage.
8. light emitting element driving circuit as claimed in claim 1, wherein this reference current value is the minimum current value of this inductance.
9. light emitting element driving method, wherein an end of this light-emitting component is coupled to the negative electrode of a supply voltage and a diode by an inductance, the other end of this light-emitting component then couples the anode of this diode and the first end of a switch, and the second end of this switch couples a common electric potential, and this light emitting element driving method comprises:
The control end of one signal to this switch is provided, with the conducting of controlling this switch with close;
Electric conduction flow valuve according to this switch determines whether close this switch by this signal; And
Relatively electric conduction flow valuve and a reference current value of this switch when this switch of conducting producing a comparative result, and are dynamically adjusted the time span of closing this switch according to this comparative result by this signal.
10. light emitting element driving method as claimed in claim 9, wherein this light-emitting component is comprised of the light-emitting diode of a plurality of series connection, and this supply voltage is direct voltage.
11. light emitting element driving method as claimed in claim 9, wherein this reference current value is the minimum current value of this inductance.
12. light emitting element driving circuit, be suitable for driving a light-emitting component, wherein an end of this light-emitting component is coupled to the negative electrode of a supply voltage and a diode, and the other end of this light-emitting component then couples the anode of this diode by an inductance, and this light emitting element driving circuit comprises:
One switch has first end, the second end and control end, and the first end of this switch couples the anode of this diode;
One current sensing circuit couples the second end of this switch, and determines whether to produce a closing control signals according to the electric conduction flow valuve of this switch; And
One ON-OFF control circuit, couple control end and second end of this current sensing circuit and this switch, in order to the conducting of controlling this switch with close, and this ON-OFF control circuit relatively electric conduction flow valuve and reference current value of this switch when this switch of conducting, to produce a comparative result, and close this switch according to this closing control signals, and dynamically adjust the time span of closing this switch according to this comparative result.
13. light emitting element driving method, wherein an end of this light-emitting component is coupled to the negative electrode of a supply voltage and a diode, the other end of this light-emitting component then couples the anode of this diode and the first end of a switch by an inductance, and the second end of this switch couples a common electric potential, and this light emitting element driving method comprises:
The control end of one signal to this switch is provided, with the conducting of controlling this switch with close;
Electric conduction flow valuve according to this switch determines whether close this switch by this signal; And
Relatively electric conduction flow valuve and a reference current value of this switch when this switch of conducting producing a comparative result, and are dynamically adjusted the time span of closing this switch according to this comparative result by this signal.
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|---|---|---|---|
| CN2008101319555A CN101621876B (en) | 2008-07-02 | 2008-07-02 | Luminous element drive circuit and method thereof |
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|---|---|---|---|
| CN2008101319555A CN101621876B (en) | 2008-07-02 | 2008-07-02 | Luminous element drive circuit and method thereof |
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| CN102123536B (en) * | 2010-01-12 | 2013-10-30 | 冠捷投资有限公司 | Light-emitting diode driving circuit |
| CN102469663B (en) * | 2010-11-17 | 2015-01-21 | 通嘉科技股份有限公司 | Control circuit, related integrated circuit and control method for light-emitting diode (LED) |
| TWI465148B (en) * | 2011-03-17 | 2014-12-11 | Green Solution Tech Co Ltd | Led driving circuit and led driving controller |
| US9875697B2 (en) * | 2011-08-30 | 2018-01-23 | Magnachip Semiconductor, Ltd. | Parallel constant current LED driving units for driving a LED string and method of performing the same |
| US11502608B2 (en) | 2018-01-29 | 2022-11-15 | Rohm Co., Ltd. | Light-emitting element driving control device and light-emitting element driving circuit device |
| CN113541514B (en) * | 2021-07-21 | 2023-03-14 | 艾科微电子(深圳)有限公司 | Synchronous rectification controller and control method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1780512A (en) * | 2004-10-01 | 2006-05-31 | 松下电器产业株式会社 | Semiconductor circuit for driving led and led driving circuit therewith |
| CN1802056A (en) * | 2005-11-11 | 2006-07-12 | 王际 | LED drive circuit and control method |
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| Publication number | Publication date |
|---|---|
| CN101621876A (en) | 2010-01-06 |
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