CN102065603A - Load drive circuit and multi-load feedback circuit - Google Patents
Load drive circuit and multi-load feedback circuit Download PDFInfo
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- CN102065603A CN102065603A CN2010105036849A CN201010503684A CN102065603A CN 102065603 A CN102065603 A CN 102065603A CN 2010105036849 A CN2010105036849 A CN 2010105036849A CN 201010503684 A CN201010503684 A CN 201010503684A CN 102065603 A CN102065603 A CN 102065603A
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Abstract
The invention discloses a load drive circuit and a multi-load feedback circuit. The power for driving a light-emitting diode (LED) module is adjusted according to potential of one or more potential-shortage current-sharing terminals of a current-sharing circuit in an LED driving device, so that the LED device can maintain higher operating efficiency under the condition that the current of LED strings in the LED module is consistent.
Description
Technical field
The present invention relates to a kind of load driving circuits and multi-load feedback circuit, refer to a kind of especially in order to drive the load driving circuits and the multi-load feedback circuit of many string light-emitting diodes.
Background technology
See also Fig. 1, be the known circuit diagram of deciding the led current drive unit of voltage driving mode.The led current drive unit comprises a flow equalizing circuit 10, a light-emitting diode (LED) module 60 and a power supply unit 70.The voltage feedback signal VFB that power supply unit 70 produces by a voltage feedback loop makes output voltage VO UT stable.Light-emitting diode (LED) module 60 comprises a plurality of light emitting diode string, is parallel between power supply unit 70 and the flow equalizing circuit 10.The current mirror that flow equalizing circuit 10 has comprised a current setting resistor 11 and has been made up of a transistor 12 and a plurality of transistor 20.Current setting resistor 11 1 ends couple a voltage VCC, and the other end couples transistor 12 and transistor 12 flowed through one set electric current.Transistor 20 mode one to one connects respective leds string in the light-emitting diode (LED) module 60, and mirror is set electric current with the lumination of light emitting diode of flowing through.So, each light-emitting diode in the light-emitting diode (LED) module 60 is flowed through roughly the same electric current and is made luminosity convergence unanimity.
Because critical voltage (Threshold Voltage) difference between light-emitting diode is not little, make required driving voltage value and inequality under the same current.For instance, suppose to flow through under the electric current of 20mA, single the required driving voltage of light-emitting diode roughly drops on 3.4～3.8V, one band, and each light emitting diode string in the light-emitting diode (LED) module 60 forms by the series connection of 20 light-emitting diode, so the required drive voltage range of light emitting diode string is 68～76V, the driving voltage difference between each light emitting diode string will be born by the transistor switch 20 of correspondence.In addition, transistor switch 20 must be operated at saturation region competence exertion mirror function of current.Therefore, for guaranteeing each light emitting diode string homomergic flow through identical electric current, the output voltage VO UT that power supply unit 70 provides must be higher than high driving voltage, and for example 80V makes transistor switch 20 can guarantee to operate in the saturation region.
Yet in fact the required driving voltage of light emitting diode string is difficult to confirm one by one in advance, so the high driving voltage of light emitting diode string is not necessarily just inevitable up to 76V in the light-emitting diode (LED) module 60.Therefore provide the high driving voltage of crossing of 80V to cause the low of luminous efficiency on the contrary.In addition, arbitrary light-emitting diode in light emitting diode string damaged open circuit and caused light emitting diode string not luminous, some light-emitting diode meeting Zener diode in parallel (Zener Diode), even if make light-emitting diode in parallel damage open circuit, also can pass through Zener diode conducting electric current.The avalanche voltage of Zener diode (breakdown voltage) can be set on the critical voltage of light-emitting diode, for example: 2V, and to avoid the misoperation of Zener diode.In this case,, cause the driving voltage of light emitting diode string up to improve nearly 4V, just might cause the electric current of light emitting diode string to decline to a great extent or even can't be luminous if there are two light-emitting diodes to damage in the light emitting diode string.And if the output voltage VO UT that power supply unit 70 is provided up improves again, but make luminous efficiency more low.
Summary of the invention
In view of the led current drive unit of deciding voltage driving mode in the known technology for guaranteeing that light-emitting diode (LED) module can stabilized illumination, be higher than required driving voltage and provide, yet too high driving voltage causes the efficient of light emitting diode drive device low.The present invention is in order to improve the efficient of light emitting diode drive device, adjust the electric power of light-emitting diode assembly driven for emitting lights diode (led) module according to the current potential of the current-sharing terminal of one or more current potential deficiencies of the flow equalizing circuit in the light emitting diode drive device, make also can keep under the electric current unanimity of each light emitting diode string of light-emitting diode assembly in light-emitting diode (LED) module to operate in preferable efficient.
To achieve the above object, the invention provides a kind of multi-load feedback circuit, use so that a load driving circuits adjustment drives the electric power of a plurality of loads in parallel.The multi-load feedback circuit comprises a plurality of semiconductor switchs, each semiconductor switch has one first end, one second end and one the 3rd end, these first end correspondences couple a plurality of reference potentials, these second ends are coupled to corresponding load in a plurality of loads, these the 3rd ends are coupled to each other and produce a detection signal with each conducting state according to the semiconductor switch in these a plurality of conductings, make load driving circuits adjust the electric power that drives a plurality of loads in view of the above.
The present invention also provides a kind of load driving circuits, in order to drive a plurality of light emitting diode string in parallel.Load driving circuits comprises a power supply unit, a flow equalizing circuit and a multi-load feedback circuit.Power supply unit couples a plurality of light emitting diode string, and is luminous in order to drive a plurality of light emitting diode string.Flow equalizing circuit has a plurality of current-sharing terminals, and correspondence couples a plurality of light emitting diode string, in order to the electric current of equiulbrium flow through a plurality of light emitting diode string.The a plurality of semiconductor switchs of multi-load feedback circuit tool, be coupled in a plurality of current-sharing terminals corresponding current-sharing terminal, this multi-load feedback circuit determines whether conducting according to the current potential of corresponding current-sharing terminal in this a plurality of current-sharing terminals and the reference potential in a plurality of reference points position or by the semiconductor switch of correspondence.Wherein, the multi-load feedback circuit and according to the current potential of the current-sharing terminal of these semiconductor switch correspondences of conducting to produce a detection signal, adjustment drives the electric power of a plurality of light emitting diode string according to detection signal to make power supply unit.
Therefore, the driving electric that load driving circuits of the present invention provides can be set in reduced levels, and cooperates the required electric power height of actual leds module to be adjusted again, and efficient is promoted.
Above general introduction and ensuing detailed description are all exemplary in nature, are in order to further specify protection scope of the present invention.And relevant other objects and advantages of the present invention will be set forth in follow-up explanation and accompanying drawing.
Description of drawings
Fig. 1 is the known circuit diagram of deciding the led current drive unit of voltage driving mode;
Fig. 2 is the circuit diagram according to load driving circuits of the present invention;
Fig. 3 is the circuit diagram according to the multi-load feedback circuit of one first embodiment of the present invention;
Fig. 4 is the circuit diagram according to the multi-load feedback circuit of one second embodiment of the present invention;
Fig. 5 is the circuit diagram according to the multi-load feedback circuit of one the 3rd embodiment of the present invention;
Fig. 6 is the circuit diagram according to the multi-load feedback circuit of one the 4th embodiment of the present invention;
Fig. 7 is the circuit diagram according to the multi-load feedback circuit of one the 5th embodiment of the present invention;
Fig. 7 A is the circuit diagram according to the multi-load feedback circuit of one the 6th embodiment of the present invention;
Fig. 8 is the circuit diagram according to the multi-load feedback circuit of one the 7th embodiment of the present invention;
Fig. 8 A is the circuit diagram according to the multi-load feedback circuit of one the 8th embodiment of the present invention.
[main element description of reference numerals]
Known technology:
Current setting resistor 11
Light-emitting diode (LED) module 60
Power supply unit 70
Voltage feedback signal VFB
Output voltage VO UT
Voltage VCC
The present invention:
Multi-load feedback circuit 110,210,310,410,510,610,710
Flow equalizing circuit 120,220,320,420,520,620,720
Current-sharing unit 222
Light-emitting diode (LED) module 160
Power supply unit 170
Semiconductor switch 212,312,412,512,612,712
Decision circuitry 214,614
Output voltage VO
Current-sharing terminal DA1～DAn
Detection signal VD
Feedback signal FB
Common reference current potential VREF
Judge reference potential Vr
Reference potential VREF1～VREFn
Transistor switch SW
Resistance R
Error amplifier EA
Driving voltage VDD
Embodiment
See also Fig. 2, be circuit diagram according to load driving circuits of the present invention.Load driving circuits comprises a multi-load feedback circuit 110, a flow equalizing circuit 120 and a power supply unit 170, in order to drive a light-emitting diode (LED) module 160, wherein light-emitting diode (LED) module 160 comprises a plurality of light emitting diode string in parallel, and each light emitting diode string comprises a plurality of light-emitting diodes of series connection.Power supply unit 170 couples a plurality of light emitting diode string in the light-emitting diode (LED) module 160, and is luminous to drive a plurality of light emitting diode string in order to an output voltage VO to be provided.Flow equalizing circuit 120 has a plurality of current-sharing terminal DA1～DAn, and correspondence couples a plurality of light emitting diode string, in order to the electric current of equiulbrium flow through these a plurality of light emitting diode string, makes the electric current of a plurality of light emitting diode string roughly the same.Multi-load feedback circuit 110 is coupled to a plurality of current-sharing terminal DA1～DAn, and produce a detection signal VD or a feedback signal FB according to the current potential of each this current-sharing terminal, make power supply unit 170 adjust the electric power of driven for emitting lights diode (led) module 160 according to detection signal VD or feedback signal FB.So, the current potential of a plurality of current-sharing terminal DA1～DAn is guaranteed on a predetermined potential, but be unlikely to too high, the efficient of load driving circuits is maintained on the high level.
Then, see also Fig. 3, be circuit diagram according to the multi-load feedback circuit of one first embodiment of the present invention.Multi-load feedback circuit 210 comprises a plurality of semiconductor switchs 212 and a decision circuitry 214.Each semiconductor switch 212 all has one first end, one second end and one the 3rd end, and first end couples a common reference potential VREF.Second end is coupled to a plurality of current-sharing terminal DA1～DAn of flow equalizing circuit 220, promptly is couple to a plurality of light emitting diode string in the light-emitting diode (LED) module shown in Figure 2 160.The 3rd end is coupled to each other to produce a detection signal VD to decision circuitry 214.
In the present embodiment, each semiconductor switch 212 in the multi-load feedback circuit 210 comprises two MOS field-effect transistors, and the drain electrode of two MOS field-effect transistors electrically is connected to each other and grid is connected to common reference current potential VREF jointly.And one in two source electrodes of two MOS field-effect transistors couple current-sharing terminal corresponding among a plurality of current-sharing terminal DA1～DAn, and another is couple to decision circuitry 214.In addition, the body diode of two MOS field-effect transistors is oppositely each other, is under the state that ends at two MOS field-effect transistors avoiding, and current signal or voltage signal transmit by the body diode of two MOS field-effect transistors.Decision circuitry 214 comprises a comparator, and the end of oppisite phase of comparator receives detection signal VD, and non-oppisite phase end receives common reference current potential VREF, produces feedback signal FB in output.
When arbitrary current potential of a plurality of current-sharing terminal DA1～DAn is lower than common reference current potential VREF one predetermined potential poor (conducting voltage that is semiconductor switch 212 is poor) when above, will make semiconductor switch 212 conductings, otherwise end.That is to say, when semiconductor switch 212 can determine whether conducting according to the current potential of the current-sharing terminal of correspondence or ends, and decide the level of detection signal VD by the current potential of the current-sharing terminal of semiconductor switch 212 correspondences of conducting.Because in the present embodiment, semiconductor switch 212 comprises two MOS field-effect transistors, so the level of detection signal VD is the mean value of current potential of current-sharing terminal of semiconductor switch 212 correspondences of conducting, and it is poor to be lower than at least one predetermined potential of common reference current potential VREF.Therefore, decision circuitry 214 can be exported the feedback signal FB of high level.Power supply unit 170 shown in Figure 2 is when receiving the feedback signal FB of high level, can improve electric power in order to driven for emitting lights diode (led) module 160, just can improve output voltage VO, current-sharing terminal DA1～DAn current potential is improved, FB transfers low level to feedback signal, and promptly current-sharing terminal DA1～DAn current potential all is greater than or equal to common reference current potential VREF.
Therefore, load driving circuits of the present invention can be adjusted the electric power of driven for emitting lights diode (led) module 160 according to the signal of multi-load feedback circuit, make the current potential of each current-sharing terminal all be greater than or equal to a predetermined current potential, but when the current potential of the current-sharing terminal of potential minimum all is greater than or equal to a predetermined current potential, load driving circuits just no longer promotes the electric power of driven for emitting lights diode (led) module 160, make the current potential and the potential difference between ground connection of current-sharing terminal unlikely too high, therefore and the efficient of holding circuit in higher level.
See also Fig. 4, be circuit diagram according to the multi-load feedback circuit of one second embodiment of the present invention.Multi-load feedback circuit 310 comprises a plurality of semiconductor switchs 312, an error amplifier 314, a resistance 316 and a transistor switch 318.Each semiconductor switch 312 all has one first end, one second end and one the 3rd end, and first end couples a common reference potential VREF.Second end is coupled to a plurality of current-sharing terminal DA1～DAn of flow equalizing circuit 320.The 3rd end is coupled to each other and is couple to error amplifier 314 to produce a detection signal VD to error amplifier 314.The circuit of the circuit of semiconductor switch 312 in the present embodiment and operation and semiconductor switch 212 shown in Figure 3 is identical, so be not repeated at this.
Multi-load feedback circuit 310 shown in the present embodiment and multi-load feedback circuit 210 maximum different being shown in Figure 3 with error amplifier 314, resistance 316 and transistor switch 318 replacement decision circuitry 214.The drain electrode of transistor switch 318 couples a driving voltage VDD, source electrode couples the non-return end of resistance 316 and error amplifier 314, and grid couples common reference current potential VREF, therefore transistor switch 318 maintains conducting state, its grid is poor to keeping a conducting voltage between source electrode, and just to be that common reference current potential VREF deducts conducting voltage poor for the signal level that non-return end received of error amplifier 314.And semiconductor switch 312 also can cause the pressure drop of conducting voltage when being lower than common reference current potential VREF one predetermined potential difference conducting because of current-sharing terminal corresponding among current-sharing terminal DA1～DAn.Therefore, by the setting of resistance 316 and transistor switch 318, pressure drop that can compensation semiconductor's switch 312.In addition, error amplifier 314 can be according to the potential difference output feedback signal FB of backward end and non-return end, adjust the electric power of driven for emitting lights diode (led) modules 160 to adjust as shown in Figure 2 power supply unit 170, the current potential of current-sharing terminal DA1～DAn is equal to or is higher than (common reference current potential VREF one conducting voltage is poor).
Please refer to Fig. 5, be circuit diagram according to the multi-load feedback circuit of one the 3rd embodiment of the present invention.Compare with multi-load feedback circuit 212 shown in Figure 3, source electrode in the multi-load feedback circuit 412 couples the MOS field-effect transistor of current-sharing terminal DA1～DAn, its grid changes the current-sharing terminal that couples correspondence into by coupling common reference current potential VREF, so MOS field-effect transistor will be maintained at cut-off state.And being lower than common reference current potential VREF one predetermined potential difference and when making 412 conductings of multi-load feedback circuit when the current potential of corresponding current-sharing terminal, the body diode that the signal of current-sharing terminal will be by the MOS field-effect transistor that ends and the MOS field-effect transistor of another conducting are passed to the backward end of comparator 414.Therefore, the multi-load feedback circuit 412 of present embodiment can be as the multi-load feedback circuit shown in the embodiment of former examples, and the feedback signal FB that is produced by comparator 414 comes the control load drive circuit to adjust the electric power of driven for emitting lights diode (led) module 160.Since two MOS field-effect transistors in the multi-load feedback circuit 412 one owing to be in cut-off state always, only show diode characteristic by body diode, therefore will dominate the height of detection signal VD by the current-sharing terminal of potential minimum among current-sharing terminal DA1～DAn, make the current potential of the current-sharing terminal of potential minimum all be greater than or equal to a predetermined potential, all be greater than or equal to predetermined potential so can guarantee all current-sharing terminal DA1～DAn.
Please refer to Fig. 6, be circuit diagram according to the multi-load feedback circuit of one the 4th embodiment of the present invention.Multi-load feedback circuit 510 comprises a plurality of semiconductor switchs 512, each a plurality of semiconductor switch 512 comprises a N transistor npn npn switch, its grid couples common reference current potential VREF, one of its source electrode and drain electrode couples current-sharing terminal corresponding among the current-sharing terminal DA1～DAn of flow equalizing circuit 520, another is coupled to each other to produce a detection signal VD, and its substrate all is coupled to ground.Because substrate couples ground, so the body diode in the N transistor npn npn switch can be guaranteed to end at contrary state partially.Therefore, a plurality of semiconductor switchs 512 only at the current potential of current-sharing terminal DA1～DAn than the low predetermined potential difference of common reference current potential VREF and just transmit the current potential of current-sharing terminal DA1～DAn to detection signal VD during conducting.The level of the detection signal VD of this moment will be as embodiment illustrated in fig. 3, is the mean value of the current potential of the current-sharing terminal of semiconductor switch 512 correspondences of conducting.At this moment, power supply unit 170 can improve electric power in order to driven for emitting lights diode (led) module 160 according to detection signal VD, makes current potential among current-sharing terminal DA1～DAn be promoted to all semiconductor switchs 512 one by one than the current-sharing terminal current potential of the low predetermined potential difference of common reference current potential VREF and is cut-off state.
In addition, multi-load feedback circuit of the present invention has the circuit of current-sharing effect by flow equalizing circuit that current mirroring circuit constitutes 520 or other as also can arranging in pairs or groups as shown in Figure 6 except that the flow equalizing circuit that can be constituted with a plurality of current-sharings unit 222 shown in Figure 3 collocation.In Fig. 6, current mirroring circuit has a plurality of grids and source electrode transistor switch connected to one another to constitute, the electric current I mirror that one current source is produced makes the electric current that is equated by the formed current-sharing terminal DA1 of the drain electrode of transistor switch～DAn conducting to each transistor switch of flowing through.
The multi-load feedback circuit produces a detection signal or the feedback signal except using MOS field-effect transistor to reach as above-mentioned embodiment, also can use bipolar transistor to be used as the current potential detecing element of current-sharing terminal.Wherein the emitter of bipolar transistor and base stage wherein one couple a common reference potential, another is coupled to current-sharing terminal corresponding in a plurality of current-sharing terminals.So, when the current potential of arbitrary current-sharing terminal and common reference potential difference arrive its forward bias voltage drop and when making the bipolar transistor conducting, can be with the bipolar transistor transmission of the current potential of this current-sharing terminal by conducting, and reach as the function as the foregoing description.
See also Fig. 7, be circuit diagram according to the multi-load feedback circuit of one the 5th embodiment of the present invention.Compare with the embodiment of Fig. 6, multi-load feedback circuit 610 in the present embodiment comprises a plurality of semiconductor switchs 612, and each a plurality of semiconductor switch 612 is made of a PNP bipolar transistor and a resistance.The base stage that the emitter of this bipolar transistor couples common reference current potential VREF, bipolar transistor is coupled to the current-sharing terminal DA1～DAn of flow equalizing circuit 620 by resistance and the collection utmost point of bipolar transistor is coupled to each other.When being lower than common reference current potential VREF one predetermined potential difference, the current potential of the current-sharing terminal of potential minimum among current-sharing terminal DA1～DAn can make corresponding bipolar transistor conducting, and by the height of the leading detection signal VD of current potential of the current-sharing terminal of potential minimum.
In the present embodiment, flow equalizing circuit 620 receives a dim signal DIM, to provide according to dim signal DIM or to stop electric current.This moment is because the current potential of current-sharing terminal DA1～DAn or so change.So detection signal VD can pass through a filter circuit 616, noise when detection signal VD is carried out filtering with the filtering light modulation, and be sent to decision circuitry 614, make decision circuitry 614 judge reference potential Vr and detection signal VD output feedback signal FB according to one, make load driving circuits adjust the electric power size that is provided, judge that wherein reference potential Vr and common reference potential VREF can be identical or different level according to this feedback signal FB.
In addition, the common reference current potential VREF that semiconductor switch 612 is received also can be different potentials value VREF1～VREFn, with reference to figure 7A, is the circuit diagram according to the multi-load feedback circuit of one the 6th embodiment of the present invention.Multi-load feedback circuit 610 in the present embodiment comprises a plurality of semiconductor switchs 612, and each a plurality of semiconductor switch 612 is made of a PNP bipolar transistor and a diode, the emitter of each bipolar transistor couples the corresponding reference potential of a plurality of reference potential VREF1～VREFn, the collection utmost point of each bipolar transistor is coupled to each other, stop electric current according to dim signal DIM or when the circuit abnormality of multi-load feedback circuit made that the end-point voltage of current-sharing terminal DA1～DAn rises, the base stage of bipolar transistor-collection utmost point or base-emitter may produce contrary inclined to one side phenomenon in flow equalizing circuit 620.When surpassing bipolar transistor withstand voltage when contrary inclined to one side overtension, bipolar transistor can be damaged.Therefore, present embodiment couples a diode between the current-sharing terminal DA1～Dan of the base stage of bipolar transistor and flow equalizing circuit 620, can prevent the problem that the bipolar transistor in the semiconductor switch 612 may be damaged because of withstand voltage deficiency.Compared to embodiment shown in Figure 7, present embodiment changes common reference current potential VREF into a plurality of reference potential VREF1～VREFn.A plurality of reference potential VREF1～VREFn correspondence is coupled to the emitter of the bipolar transistor in a plurality of semiconductor switchs 612, and the current potential of a plurality of reference potential VREF1～VREFn can be set according to (current-sharing terminal DA1～DAn is coupled) light emitting diode string of correspondence, thus a plurality of reference potential VREF1～VREFn can be identical, part is identical or all inequality.When bipolar transistor is lower than the one predetermined potential difference conducting of corresponding reference current potential because of the current potential of the current-sharing terminal of correspondence, can adjust the level height of detection signal VD according to the current potential of this current-sharing terminal.In addition, judge that reference potential Vr is higher than the arbitrary of a plurality of reference potential VREF1～VREFn.In other words, the feedback decision level point of the feedback signal FB of multi-load feedback circuit 610 of the present invention is to set separately with the decision level point (based on the level of corresponding reference current potential with adjustment detection signal VD) of each current-sharing terminal, the flexibility ratio that restriction in the time of so can reducing circuit application and increase are used.
Please refer to Fig. 8, be circuit diagram according to the multi-load feedback circuit of one the 7th embodiment of the present invention.Multi-load feedback circuit 710 in the present embodiment comprises a plurality of semiconductor switchs 712, and each a plurality of semiconductor switch 712 is made of a NPN bipolar transistor and a resistance.The base stage of this bipolar transistor is coupled to common reference current potential VREF by resistance, the emitter of bipolar transistor couples the current-sharing terminal DA1～DAn of flow equalizing circuit 720 and the collection utmost point of bipolar transistor is coupled to each other, and can make corresponding bipolar transistor conducting and by the height of the leading detection signal VD of current potential of the current-sharing terminal of potential minimum when the current potential of the current-sharing terminal of potential minimum among current-sharing terminal DA1～DAn is lower than common reference current potential VREF one predetermined potential difference.
Certainly, the common reference current potential VREF of Fig. 8 also can change a plurality of reference potential VREF1～VREFn into.Please refer to Fig. 8 A, be circuit diagram according to the multi-load feedback circuit of one the 8th embodiment of the present invention.Multi-load feedback circuit 710 in the present embodiment comprises a plurality of semiconductor switchs 712, and each a plurality of semiconductor switch 712 is made of a NPN bipolar transistor, a resistance and two diodes, wherein first diode is coupled to the wherein reference potential of NPN bipolar transistor and a plurality of reference potential VREF1～VREFn, and second diode is coupled to the collection utmost point of NPN bipolar transistor.The emitter of this bipolar transistor couples the current-sharing terminal DA1～DAn of flow equalizing circuit 720, stop electric current according to dim signal DIM or when the circuit abnormality of multi-load feedback circuit made that the end-point voltage of current-sharing terminal DA1～DAn rises, the emitter-base stage of bipolar transistor or emitter-collection very likely produced against inclined to one side phenomenon in flow equalizing circuit 720.Therefore, present embodiment is coupled to diode and resistance between the base stage and a plurality of reference potential VREF1～VREFn of bipolar transistor, and the collection utmost point of bipolar transistor is coupled to each other by diode, causes the problem of damage because of withstand voltage deficiency to prevent bipolar transistor in the semiconductor switch 712.
As mentioned above, the present invention discloses with preferred embodiment hereinbefore, and right those of ordinary skills it should be understood that this embodiment only is used to describe the present invention, and should not be read as restriction protection scope of the present invention.It should be noted that the variation and the displacement of all and this embodiment equivalence all should be covered by in the category of the present invention.Therefore, protection scope of the present invention is worked as with being as the criterion that claim was defined.
Claims (20)
1. a multi-load feedback circuit is used so that a load driving circuits adjustment drives the electric power of a plurality of loads in parallel, it is characterized in that this multi-load feedback circuit comprises:
A plurality of semiconductor switchs, each this semiconductor switch has one first end, one second end and one the 3rd end, described these first end correspondences couple a plurality of reference potentials, described these second end correspondences are coupled to the corresponding load in these a plurality of loads, described these the 3rd ends are coupled to each other and produce a detection signal with each conducting state according to the semiconductor switch in these a plurality of conductings, make this load driving circuits adjust the electric power that drives these a plurality of loads in view of the above.
2. multi-load feedback circuit as claimed in claim 1 is characterized in that, more comprises a decision circuitry, in order to produce a feedback signal according to this detection signal, makes this load driving circuits drive the electric power of these a plurality of loads according to this feedback signal adjustment.
3. multi-load feedback circuit as claimed in claim 1 or 2, it is characterized in that, each this semiconductor switch comprises one first MOS field-effect transistor and one second MOS field-effect transistor, wherein the drain electrode of the drain electrode of this first MOS field-effect transistor and this second MOS field-effect transistor electrically connects, the grid correspondence of the grid of this first MOS field-effect transistor and this second MOS field-effect transistor couples these a plurality of reference potentials reference potential wherein, the source electrode of this first MOS field-effect transistor is coupled to the corresponding load in these a plurality of loads, and the body diode of the body diode of this first MOS field-effect transistor and this second MOS field-effect transistor is reverse each other.
4. multi-load feedback circuit as claimed in claim 1 or 2, it is characterized in that, each this semiconductor switch comprises one first MOS field-effect transistor and one second MOS field-effect transistor, wherein the drain electrode of the drain electrode of this first MOS field-effect transistor and this second MOS field-effect transistor electrically connects, the grid of this first MOS field-effect transistor and source electrode electrically connect, the grid correspondence of this second MOS field-effect transistor couples these a plurality of reference potentials reference potential wherein, the source electrode of this first MOS field-effect transistor is coupled to the corresponding load in these a plurality of loads, and the body diode of the body diode of this first MOS field-effect transistor and this second MOS field-effect transistor is reverse each other.
5. multi-load feedback circuit as claimed in claim 1 or 2, it is characterized in that, each this semiconductor switch comprises a MOS field-effect transistor, the grid correspondence of each this MOS field-effect transistor couples these a plurality of reference potentials reference potential wherein, the source electrode of each this MOS field-effect transistor is coupled to the corresponding load in these a plurality of loads, and the substrate ground connection of each this MOS field-effect transistor.
6. multi-load feedback circuit as claimed in claim 1 or 2, it is characterized in that, each this semiconductor switch comprises a bipolar transistor, the emitter of each this a bipolar transistor and base stage correspondence wherein couples these a plurality of reference potentials reference potential wherein, and another of the emitter of each this bipolar transistor and base stage is coupled to the corresponding load in these a plurality of loads.
7. multi-load feedback circuit as claimed in claim 6 is characterized in that, more comprises a plurality of diodes, and wherein each this diode is coupled in these a plurality of bipolar transistors in the corresponding bipolar transistor and these a plurality of loads between the corresponding load.
8. multi-load feedback circuit as claimed in claim 6, it is characterized in that, more comprise many group diodes, wherein each group diode comprises one first diode and one second diode, this first diode is coupled in these a plurality of bipolar transistors in the corresponding bipolar transistor and these a plurality of reference potentials between the corresponding reference potential, and this second diode is coupled to the collection utmost point of corresponding bipolar transistor in a plurality of bipolar transistors.
9. multi-load feedback circuit as claimed in claim 2 is characterized in that this decision circuitry comprises a comparator, and the end of oppisite phase of this comparator receives this detection signal, and the non-oppisite phase end of this comparator receives a common reference potential.
10. multi-load feedback circuit as claimed in claim 9, it is characterized in that, this decision circuitry comprises a comparator and a transistor switch, this transistor switch has one first end, one second end and a control end, this first end couples a driving voltage, this control end couples this common reference current potential, and this second end couples the non-oppisite phase end of this comparator, and the end of oppisite phase of this comparator receives this detection signal.
11. multi-load feedback circuit as claimed in claim 9 is characterized in that, the level of this common reference current potential is higher than the level of arbitrary these a plurality of reference potentials.
12. multi-load feedback circuit as claimed in claim 11 is characterized in that, these a plurality of reference potentials are same potential.
13. a load driving circuits in order to drive a plurality of light emitting diode string in parallel, is characterized in that this load driving circuits comprises:
One power supply unit couples this a plurality of light emitting diode string, and is luminous in order to drive these a plurality of light emitting diode string;
One flow equalizing circuit has a plurality of current-sharing terminals, and correspondence couples this a plurality of light emitting diode string, and this flow equalizing circuit is in order to the electric current of equiulbrium flow through these a plurality of light emitting diode string; And
One multi-load feedback circuit, the a plurality of semiconductor switchs of tool, be coupled in these a plurality of current-sharing terminals corresponding current-sharing terminal, this multi-load feedback circuit determines whether conducting according to a corresponding reference potential in the current potential of corresponding current-sharing terminal in this a plurality of current-sharing terminals and a plurality of reference potential or by this semiconductor switch of correspondence;
Wherein, this multi-load feedback circuit and according to the current potential of the current-sharing terminal of described these semiconductor switch correspondences of conducting to produce a detection signal, make this power supply unit drive the electric power of these a plurality of light emitting diode string according to this detection signal adjustment.
14. load driving circuits as claimed in claim 13, it is characterized in that, each this semiconductor switch comprises one first MOS field-effect transistor and one second MOS field-effect transistor, wherein the drain electrode of this first MOS field-effect transistor and this second MOS field-effect transistor electrically connects, the grid correspondence of the grid of this first MOS field-effect transistor and this second MOS field-effect transistor couples these a plurality of reference potentials reference potential wherein, the source electrode of this first MOS field-effect transistor is coupled to current-sharing terminal corresponding in these a plurality of current-sharing terminals, and the body diode of the body diode of this first MOS field-effect transistor and this second MOS field-effect transistor is reverse each other.
15. load driving circuits as claimed in claim 13, it is characterized in that, each this semiconductor switch comprises one first MOS field-effect transistor and one second MOS field-effect transistor, wherein the drain electrode of the drain electrode of this first MOS field-effect transistor and this second MOS field-effect transistor electrically connects, the grid of this first MOS field-effect transistor and source electrode electrically connect, the grid correspondence of this second MOS field-effect transistor couples these a plurality of reference potentials reference potential wherein, the source electrode of this first MOS field-effect transistor is coupled to current-sharing terminal corresponding in these a plurality of current-sharing terminals, and the body diode of the body diode of this first MOS field-effect transistor and this second MOS field-effect transistor is reverse each other.
16. load driving circuits as claimed in claim 13, it is characterized in that, each this semiconductor switch comprises a MOS field-effect transistor, the grid correspondence of this MOS field-effect transistor couples these a plurality of reference potentials reference potential wherein, the source electrode of this MOS field-effect transistor is coupled to current-sharing terminal corresponding in these a plurality of current-sharing terminals, and the substrate ground connection of this MOS field-effect transistor.
17. load driving circuits as claimed in claim 13, it is characterized in that, each this semiconductor switch comprises a bipolar transistor, a correspondence wherein of the emitter of this bipolar transistor and base stage couples these a plurality of reference potentials reference potential wherein, and the emitter of this bipolar transistor and in the base stage another are coupled to current-sharing terminal corresponding in these a plurality of current-sharing terminals.
18. load driving circuits as claimed in claim 17 is characterized in that, more comprises a plurality of diodes, wherein each this diode is coupled in these a plurality of bipolar transistors in the corresponding bipolar transistor and these a plurality of loads between the corresponding load.
19. multi-load feedback circuit as claimed in claim 17, it is characterized in that, more comprise many group diodes, wherein each group diode comprises one first diode and one second diode, this first diode is coupled in these a plurality of bipolar transistors in the corresponding bipolar transistor and these a plurality of reference potentials between the corresponding reference potential, and this second diode is coupled to the collection utmost point of corresponding bipolar transistor in a plurality of bipolar transistors.
20. load driving circuits as claimed in claim 17, it is characterized in that, this multi-load feedback circuit more comprises a decision circuitry, in order to produce a feedback signal according to this detection signal and a common reference potential, make this load driving circuits drive the electric power of these a plurality of loads, and the level of this common reference current potential is higher than the level of arbitrary these a plurality of reference potentials according to this feedback signal adjustment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010503684.9A CN102065603B (en) | 2009-11-18 | 2010-09-30 | Load drive circuit and multi-load feedback circuit |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910223375.3 | 2009-11-18 | ||
| CN200910223375 | 2009-11-18 | ||
| CN201010503684.9A CN102065603B (en) | 2009-11-18 | 2010-09-30 | Load drive circuit and multi-load feedback circuit |
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| CN102065603A true CN102065603A (en) | 2011-05-18 |
| CN102065603B CN102065603B (en) | 2014-03-05 |
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| CN201010503684.9A Expired - Fee Related CN102065603B (en) | 2009-11-18 | 2010-09-30 | Load drive circuit and multi-load feedback circuit |
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