CN107277978A - A kind of constant current output circuit and lighting device - Google Patents
A kind of constant current output circuit and lighting device Download PDFInfo
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- CN107277978A CN107277978A CN201710566411.0A CN201710566411A CN107277978A CN 107277978 A CN107277978 A CN 107277978A CN 201710566411 A CN201710566411 A CN 201710566411A CN 107277978 A CN107277978 A CN 107277978A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
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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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The invention provides a kind of constant current output circuit and lighting device, the constant current feedback circuit that the constant current output circuit includes BUCK constant-current drive circuits, is connected with the BUCK constant-current drive circuits, BUCK constant-current drive circuits can provide constant current for multiple loads, gather the current signal Jing Guo each load and export to constant current feedback circuit.The load current signal of collection is converted into after voltage signal by constant current feedback circuit, it is compared with a reference signal, by the way that comparative result is fed back into BUCK constant-current drive circuits in time as feedback signal, so as to so that BUCK constant-current drive circuits quickly recognize the change of load current, when the voltage signal changed by load current signal deviates reference signal, to be adjusted in time to each load current.The embodiment of the present invention can in real time be adjusted in the case of circuit output voltage wider range to the electric current of each load, improve the precision of load output current.
Description
Technical field
The present invention relates to lighting technical field, more particularly to a kind of constant current output circuit and lighting device.
Background technology
At present, the use of LED drive power is frequently referred in light fixture product, for some light fixture products, its drive and
Light source led is not one-to-one relation, but a driving matching multiple light sources.Such case is easily caused light fixture output
The problem of voltage range is relatively wide, so as to cause the output constant current deterioration in accuracy of light fixture.
Existing drive circuit generally uses constant current driver circuit for LED, such as BUCK constant-current drive circuits (i.e. buck converter
Circuit), although the drive circuit can realize a drive circuit driving multiple light sources, the circuit is to output current
Precision has higher requirement.Therefore, the essence of output current how is effectively improved when driving light source using BUCK constant currents circuit
Degree is a urgent problem to be solved.
The content of the invention
In view of the above problems, it is proposed that the present invention so as to provide one kind overcome above mentioned problem or at least in part solve on
State the constant current output circuit and lighting device of problem.
According to an aspect of the present invention there is provided a kind of constant current output circuit, including：
BUCK constant-current drive circuits, provide constant current for multiple loads, the current signal Jing Guo each load are gathered, by it
Voltage signal is converted to outwards to export；
Constant current feedback circuit, is connected with the BUCK constant-current drive circuits, receives the BUCK constant-current drive circuits output
Voltage signal, the reference signal in the voltage signal and the constant current feedback circuit is compared and obtains comparative result,
And feedback signal is generated after comparative result is amplified, by feedback signal back to the BUCK constant-current drive circuits；
The BUCK constant-current drive circuits, the size of current Jing Guo each load is adjusted according to the feedback signal of reception, to protect
Demonstrate,prove each load current constant.
Alternatively, the constant current feedback circuit includes discharge circuit and photo-coupler, wherein,
The discharge circuit, possesses two inputs and an output end, and an input connects the BUCK constant currents and driven
Dynamic circuit, receives the voltage signal changed by the BUCK constant-current drive circuits, and another input receives the reference signal, institute
State discharge circuit and be compared the voltage signal and reference signal according to comparison rule and obtain comparative result, and knot will be compared
Fruit exports as the first output signal from its output end；
The photo-coupler, with input and output end, its input connects the output end of the discharge circuit, receives
First output signal, its output end connects the BUCK constant-current drive circuits, and the photo-coupler is exported described first
Signal is enlarged into after the second output signal, using second output signal as the feedback signal back to the BUCK constant currents
Drive circuit.
Alternatively, the voltage signal and reference signal are compared by the discharge circuit according to comparison rule, if than
Relatively result is that the voltage signal is more than the reference signal, then the first output signal exported from the discharge circuit output end
Reduce；If comparative result, which is the voltage signal, is less than the reference signal, the exported from the discharge circuit output end
One output signal increases.
Alternatively, the constant current feedback circuit also includes divider resistance, wherein,
The divider resistance connects the input of the discharge circuit output end and the photo-coupler respectively, wherein, institute
The first output signal is stated for voltage signal；
The first output signal that the divider resistance is exported to the discharge circuit carries out partial pressure, obtains partial pressure switch letter
Number, and the partial pressure switch signal is inputted to the input of the photo-coupler.
Alternatively, the photo-coupler, is received by the divider resistance to first output signal using its input
The obtained partial pressure switch signal of partial pressure is carried out, and the partial pressure switch signal is enlarged into after the second output signal, by described the
Two output signals are used as the feedback signal back to the BUCK constant-current drive circuits.
Alternatively, if first output signal of discharge circuit output reduces, the divider resistance partial pressure is obtained
The increase of partial pressure switch signal, then second output signal increase；
If first output signal increase of the discharge circuit output, the partial pressure that the divider resistance partial pressure is obtained turns
Signal reduction is changed, then second output signal reduces.
Alternatively, the BUCK constant-current drive circuits include the first sampling resistor, control IC and switch, wherein
The current signal respectively loaded is passed through in first sampling resistor, collection, and the current signal is converted into electricity
Exported after pressure signal to an input of the discharge circuit；
The control IC, with input and output end, its input connects the output end of the photo-coupler, receives institute
State the feedback signal of photo-coupler feedback, its output end connects the switch, the control IC utilize the feedback signal according to
The ON time switched described in control rule control, and make the ON time control in default maximum ON time, profit
The size of current Jing Guo the load is adjusted with the ON time length of the switch, to ensure the perseverance of each load current
It is fixed.
Alternatively, the discharge circuit includes operational amplifier, wherein,
The operational amplifier has anode and negative terminal, and the negative terminal connects first sampling resistor, the positive termination
Receive the reference signal.
Alternatively, if the feedback signal that the control IC is received reduces, the switch conduction is controlled, to increase stream
The electric current of the load is crossed, and the switch is controlled when the switch conduction times reach the default maximum ON time
Disconnect；
If the feedback signal increase that the control IC is received, switch off to reduce the switch described in control
ON time, reduces the electric current for flowing through the load.
Alternatively, the BUCK constant-current drive circuits include inductance component, and the switch includes metal-oxide-semiconductor, the metal-oxide-semiconductor
Drain electrode is connected through the inductance component with first sampling resistor, and grid connects the control IC, source electrode and the second sampling electricity
Resistance series connection.
Alternatively, the load includes light source.
According to another aspect of the present invention, a kind of lighting device is additionally provided, including：
Constant current output circuit as mentioned above；
Multiple light sources, are connected, the multiple light source is by institute with the BUCK constant-current drive circuits in the constant current output circuit
State constant current output circuit and constant current is provided.
In embodiments of the present invention, constant current output circuit includes BUCK constant-current drive circuits, drives electricity with the BUCK constant currents
The constant current feedback circuit of road connection, wherein, BUCK constant-current drive circuits can provide constant current for multiple loads, and collection is passed through
The current signal respectively loaded, is converted into voltage signal and outwards exports.Constant current feedback circuit receives BUCK constant-current drive circuits
The voltage signal of output, comparative result is obtained by the way that the reference signal in voltage signal and constant current feedback circuit is compared
Afterwards, by comparative result amplification to generate feedback signal, and by obtained feedback signal back to BUCK constant-current drive circuits.This
When, BUCK constant-current drive circuits can adjust the size of current by each load according to the feedback signal of reception, so that effectively
Ensure the constant of each load current.Thus, the embodiment of the present invention is turned the load current signal of collection using constant current feedback circuit
Change into after voltage signal, be compared with a reference signal, by the way that comparative result is fed back in time as feedback signal
To BUCK constant-current drive circuits, so as to so that BUCK constant-current drive circuits quickly recognize the change of load current, with by
When the voltage signal of load current signal conversion deviates reference signal, each load current is adjusted in time.The present invention is implemented
Example can be carried out real to the circuit of connection multi-load that is, in the case of circuit output voltage wider range to the electric current of each load
When adjust, improve load output current precision.
Further, the circuit structure of the constant current output circuit of the embodiment of the present invention is simple, it is easier to realize to circuit
It is integrated, so as to effectively save the cost of integrated circuit.
Described above is only the general introduction of technical solution of the present invention, in order to better understand the technological means of the present invention,
And can be practiced according to the content of specification, and in order to allow above and other objects of the present invention, feature and advantage can
Become apparent, below especially exemplified by the embodiment of the present invention.
According to the accompanying drawings to the detailed description of the specific embodiment of the invention, those skilled in the art will be brighter
Above-mentioned and other purposes, the advantages and features of the present invention.
Brief description of the drawings
By reading the detailed description of hereafter preferred embodiment, various other advantages and benefit is common for this area
Technical staff will be clear understanding.Accompanying drawing is only used for showing the purpose of preferred embodiment, and is not considered as to the present invention
Limitation.And in whole accompanying drawing, identical part is denoted by the same reference numerals.In the accompanying drawings：
Fig. 1 shows a kind of structural representation of BUCK constant-current drive circuits；
Fig. 2 shows the structural representation of another BUCK constant-current drive circuits；
Fig. 3 shows the structural representation of another BUCK constant-current drive circuit；And
Fig. 4 shows the structural representation of constant current output circuit according to an embodiment of the invention.
Embodiment
The exemplary embodiment of the disclosure is more fully described below with reference to accompanying drawings.Although showing the disclosure in accompanying drawing
Exemplary embodiment, it being understood, however, that may be realized in various forms the disclosure without should be by embodiments set forth here
Limited.On the contrary, these embodiments are provided to facilitate a more thoroughly understanding of the present invention, and can be by the scope of the present disclosure
Complete conveys to those skilled in the art.
First, three kinds of different BUCK constant-current drive circuits are introduced respectively：
The first, as shown in figure 1, the BUCK constant-current drive circuits (gather inductance L peak value electricity using peakvalue's checking
Stream) and the driving of low side control mode, be that circuit structure is succinct, constant current drive mode is simple the characteristics of the drive circuit；
Second, as shown in Fig. 2 the BUCK constant-current drive circuits using average detection (collection load LED electric current,
That is collection inductance L average value current) and flash driving control mode；
The third, as shown in figure 3, the control that the BUCK constant-current drive circuits are driven using average detection and low side
The characteristics of mode, drive circuit is：Detection LED output current is needed, due to constant current I0043 (integrated
Circuit, integrated circuit), i.e. " control " in Fig. 3, it carries differential feedback constant current effect.
Wherein, the above-mentioned flash referred to refers to power supply, and low side refers to ground terminal, and flash driving and the driving of low side are for adjusting
Power is tried with driving load.Specifically, flash drive finger switch is between power supply and load, and low side drive finger switch position
Between load and ground.
The embodiments of the invention provide a kind of constant current output circuit.Referring to Fig. 4, the constant current output circuit includes BUCK constant currents
Drive circuit 101 and the constant current feedback circuit 102 being connected with BUCK constant-current drive circuits 101, wherein, BUCK constant currents driving
Circuit 101 can gather the current signal Io by each load, be converted into voltage signal and outwards export, and think multiple loads
Constant current is provided.Wherein, load can be light source device, and such as LED/light source device, certainly, load can also be other yuan
Part, the embodiment of the present invention is not specifically limited to this.In addition, showing two LED in Fig. 4, other quantity is can also be certainly
Light source, the embodiment of the present invention is not specifically limited to the quantity of light source.
Constant current feedback circuit 102 can receive the voltage signal of the output of BUCK constant-current drive circuits 101, by the way that voltage is believed
Number it is compared and is obtained after comparative result with 102 reference signal Vref in constant current feedback circuit, the comparative result can be entered
Row amplification is to generate feedback signal, so that by obtained feedback signal back into BUCK constant-current drive circuits 101.Now,
BUCK constant-current drive circuits 101 can adjust the electric current Io sizes by each load LED according to the feedback signal of reception, so as to have
Effect ground ensures that each load current Io's is constant.
Two BUCK constant currents shown in Fig. 1 and Fig. 3 are driven electricity by BUCK constant-current drive circuits 101 in this embodiment
Road 101 is effectively combined, and is used average detection, the control mode of low side driving and is deposited in the prior art with overcoming
Technical problem.
The load current signal of collection is converted into after voltage signal by the embodiment of the present invention using constant current feedback circuit, with
A reference signal in constant current feedback circuit is compared, by the way that comparative result is fed back in time as feedback signal
BUCK constant-current drive circuits, so as to so that BUCK constant-current drive circuits quickly recognize the change of load current, with by bearing
When the voltage signal for carrying current signal conversion deviates reference signal, each load current is adjusted in time.The embodiment of the present invention
Circuit to connecting multi-load, i.e., can be carried out real-time in the case of circuit output voltage wider range to the electric current of each load
Adjustment, improves the precision of load output current.
With continued reference to Fig. 4, in an embodiment of the present invention, constant current feedback circuit 102 includes discharge circuit 103 and optical coupling
Device U102, wherein, discharge circuit 103 possesses two inputs and an output end, an input connection BUCK constant current driving
Circuit 101, to receive the voltage signal changed by BUCK constant-current drive circuits 101, another input receives reference signal
Vref.Voltage signal can be compared to obtain being compared knot by discharge circuit 103 according to comparison rule with reference signal Vref
Really, then comparative result is exported as the first output signal from its output end out1.Wherein, the discharge circuit 103 can be wrapped
Operational amplifier U1 is included, operational amplifier U1 has anode and negative terminal, the negative terminal can receive 101 turns of BUCK constant-current drive circuits
The voltage signal changed, anode receives reference signal Vref.
In this embodiment, discharge circuit 103 is compared voltage signal with reference signal Vref according to comparison rule
Compared with when, if comparative result be voltage signal be more than reference signal Vref, from the output end of discharge circuit 103 export first output
Signal reduces.If comparative result, which is voltage signal, is less than reference signal Vref, exported from the output end out1 of discharge circuit 103
First output signal increases.
In this embodiment, photo-coupler U102 has input and output end, and its input is located at photo-coupler
1,2 pins of U102 primary sides, connect the output end out1 of discharge circuit 103, to receive the first output of the output of discharge circuit 103
Signal, photo-coupler U102 output end, i.e. 3,4 pins positioned at photo-coupler U102 secondary, connection BUCK constant current driving electricity
Road 101, after the first output signal is enlarged into the second output signal by photo-coupler U102, can using the second output signal as
Feedback signal back is to BUCK constant-current drive circuits 101.
Wherein, photo-coupler U102 is a kind of switching device using light as media transmission electric signal, and it can realize telecommunications
Number optical signal is converted into, then is converted into by optical signal the process of electric signal.It is made up of light emitting source and light-receiving device two parts, hair
Light source and light-receiving device are assembled in same closed housing, are isolated to each other with transparent insulator.The pin of light emitting source is input
End, the pin of light-receiving device is output end.
In the embodiment, photo-coupler U102 can not only realize the amplification of signal, moreover it is possible to isolation is played to circuit and is protected
The circuit and the circuit of its output end connection that the effect of shield, i.e. photo-coupler U102 can be connected to its input are isolated,
Prevent from interfering with each other between circuit.
With continued reference to Fig. 4, in an alternate embodiment of the present invention, constant current feedback circuit 102 can also include divider resistance
The output end out1 and photo-coupler U102 of R104, the divider resistance R104 one end connection discharge circuit 103 2 pins, it is another
End connection photo-coupler U102 1 pin.When the first output signal is voltage signal, divider resistance R104 is to discharge circuit
First output signal of 103 output end out1 outputs carries out partial pressure, partial pressure switch signal is obtained, so that partial pressure switch signal is defeated
Enter to photo-coupler U102 input.After photo-coupler U102 receives partial pressure switch signal, partial pressure switch signal is entered
Row amplification is obtained after the second output signal, so that using the second output signal as feedback signal back to BUCK constant-current drive circuits
101。
In the embodiment, because VL ends have stable magnitude of voltage, therefore, the first output exported when discharge circuit 103
When signal reduces, divider resistance R104 partial pressures obtain magnitude of voltage increase, that is, the partial pressure switch signal increase obtained, now, pass through
The second output signal obtained after photo-coupler U102 amplifications can also increase.The first output signal exported when discharge circuit 103
During increase, divider resistance R104 partial pressures obtain magnitude of voltage reduction, that is, the partial pressure switch signal obtained reduces, and now, passes through optocoupler
The second output signal obtained after clutch U102 amplifications can also reduce.
With continued reference to Fig. 4, in an embodiment of the present invention, BUCK constant-current drive circuits 101 can include the first sampling electricity
Hinder R101, control IC and switch Q2.
Wherein, the first sampling resistor R101 and load LED strip connection, can gather the electric current Io by each LED, and by electric current
Signal is converted into after voltage signal, an input of output to discharge circuit 103, the one of the first sampling resistor R101 in Fig. 4
Hold concatenation operation amplifier U1 negative terminal IN1-.
Control IC has input and output end, its input connection photo-coupler U102 output end, receives optical coupling
The feedback signal of device U102 feedbacks, its output end connecting valve Q2.Control IC is opened using feedback signal according to control rule control
Q2 ON time is closed, and makes ON time control in default maximum ON time, it is long using the ON time for switching Q2
Minor warping overload LED electric current Io sizes, to ensure that each load LED current Io's is constant.
Maximum ON time in the embodiment is preset inside control IC in advance, and the numerical value of the maximum ON time is
Set according to the load LED maximum currents that can bear, according to different load LED, preset maximum ON time can not yet
Together, the embodiment of the present invention is not specifically limited to maximum ON time.
IC is controlled when switching Q2 ON time according to control rule control using feedback signal, if control IC is received
The feedback signal of photo-coupler U102 feedbacks reduces, then controlling switch Q2 is turned on, and the electric current for loading LED is flowed through to increase, and
Controlling switch Q2 when Q2 ON times reach default maximum ON time is switched to disconnect.If the feedback signal for controlling IC to receive increases
Greatly, then controlling switch Q2 disconnects reducing switch Q2 ON time, reduces the electric current Io for flowing through load LED.
In embodiment illustrated in fig. 4, BUCK constant-current drive circuits 101 include inductance L1 and the second sampling resistor Rs, and second adopts
Sample resistance Rs can play a part of protection to BUCK constant-current drive circuits 101.Switch Q2 uses metal-oxide-semiconductor, the leakage of metal-oxide-semiconductor
Pole connection inductance L1 one end, the inductance L1 other end be connected with the first sampling resistor R101, and grid connection controls IC, source electrode and
Second sampling resistor Rs connects.Certainly, switch Q2 can also use other devices, such as triode adjustment pipe, and the present invention is implemented
Example is not specifically limited to this.
In order to clearly embody the embodiment of the present invention, now the course of work to the constant current output circuit shown in Fig. 4 is entered
The complete introduction of row.
Referring to Fig. 4, load LED electric current Io is flowed through in the first sampling resistor R101 collections, and electric current Io is converted into electricity
Press after signal, input to operational amplifier U1 negative terminal IN1-, operational amplifier U1 anodes receive reference voltage signal Vref, and
The voltage signal that negative terminal IN1- is received is compared with reference voltage signal Vref.
When the voltage signal of load LED electric current Io increases, and operational amplifier U1 negative terminals IN1- is more than what anode was received
During reference voltage signal Vref, the first output signal of operational amplifier U1 output ends out1 outputs reduces.Because VL ends have
Stable magnitude of voltage, therefore divider resistance R104 carries out the partial pressure switch signal that partial pressure is obtained, i.e. optocoupler to the first output signal
Voltage increase between clutch U102 1,2 pin, and transmit between the 3 of photo-coupler U102,4 pin that (i.e. photo-coupler U102 is defeated
Go out end) electric current accordingly strengthen.When the intensifying current that photo-coupler U102 is exported, can produce on resistance R113 one it is larger
Current value, the current value feeds back to control IC input, and then by controlling IC controlling switches Q2 to disconnect, to reduce switch Q2's
ON time.So far, convection current overload LED electric current Io regulation is realized, reduces the electric current Io for flowing through load LED.
When the voltage signal of load LED electric current Io reductions, and operational amplifier U1 negative terminals IN1- is less than the benchmark of anode
During voltage signal Vref, the first output signal increase of operational amplifier U1 output ends out1 outputs.Because VL ends have stabilization
Magnitude of voltage, therefore divider resistance R104 carries out the obtained partial pressure switch signal of partial pressure, i.e. photo-coupler to the first output signal
Voltage between U102 1,2 pin reduces, and transmits weaker to the electric current between the 3 of photo-coupler U102,4 pin.Work as photo-coupler
When the electric current of U102 outputs is weaker, a less current value can be produced on resistance R113, the current value feeds back to control IC's
Input, and then by controlling IC controlling switches Q2 conductings.So far, convection current overload LED electric current Io regulation is realized, is increased
Flow through load LED electric current Io.When switching the Q2 ON times default maximum ON time of arrival, control IC can control to hold
Close Q2 to disconnect, to avoid the electric current Io for flowing through load LED is excessive from burning load LED.
In this embodiment, constant current feedback circuit 102 also includes resistance R105 and electric capacity C102, resistance R105 and electric capacity
Operational amplifier U1 negative terminal IN1- are connected to after C102 series connection, a compensation network are constituted, for ensureing that constant current output circuit is steady
Fixed work.
The control mode that the embodiment of the present invention is driven using average detection, low side, even if drive circuit correspondence is multiple negative
Carry LED and make it that the output voltage range for loading LED is wider, the size of current that can also flow through each load LED by adjustment makes to bear
Carry LED current and keep constant.Also, learnt by many experiments, the constant current output circuit using the present invention can make load LED
Constant current accuracy control within 3%.In the case where load LED current output accuracy is higher, the circuit can easily expand
Open up as dimming drive power.
Based on same inventive concept, the embodiment of the present invention additionally provides a kind of lighting device, and the lighting device includes multiple
Light source, and such as the constant current output circuit referred in any embodiment above, wherein, multiple light sources with constant current output circuit
BUCK constant-current drive circuits are connected, and constant current output circuit provides constant current for multiple light sources.
The multiple light sources referred in the embodiment are actually the load referred in foregoing embodiments, and light source can be used
LED/light source etc., the embodiment of the present invention is not specifically limited to the species of light source.
The embodiment of the present invention provides stable electricity in lighting device using constant current output circuit for the multiple light sources of connection
Stream so that the electric current of each light source can in real time be adjusted in the case of circuit output voltage wider range, improve light
The precision of source output current, and then the illuminating effect of lighting device is improved, make the light extraction of lighting device more uniform.
So far, although those skilled in the art will appreciate that detailed herein have shown and described multiple showing for the present invention
Example property embodiment, still, still can be direct according to present disclosure without departing from the spirit and scope of the present invention
It is determined that or deriving many other variations or modifications for meeting the principle of the invention.Therefore, the scope of the present invention is understood that and recognized
It is set to and covers other all these variations or modifications.
Claims (12)
1. a kind of constant current output circuit, it is characterised in that including：
BUCK constant-current drive circuits, provide constant current for multiple loads, gather the current signal Jing Guo each load, be converted
Outwards exported for voltage signal；
Constant current feedback circuit, is connected with the BUCK constant-current drive circuits, receives the electricity of the BUCK constant-current drive circuits output
Signal is pressed, the reference signal in the voltage signal and the constant current feedback circuit is compared and obtains comparative result, and will
Comparative result generates feedback signal after being amplified, by feedback signal back to the BUCK constant-current drive circuits；
The BUCK constant-current drive circuits, adjust the size of current Jing Guo each load, to ensure according to the feedback signal of reception
State each load current constant.
2. constant current output circuit according to claim 1, it is characterised in that the constant current feedback circuit includes discharge circuit
And photo-coupler, wherein,
The discharge circuit, possesses two inputs and an output end, and one of input connects the BUCK constant currents and driven
Dynamic circuit, receives the voltage signal changed by the BUCK constant-current drive circuits, and another input receives the reference signal, institute
State discharge circuit and be compared the voltage signal and reference signal according to comparison rule and obtain comparative result, and knot will be compared
Fruit exports as the first output signal from its output end；
The photo-coupler, with input and output end, its input connects the output end of the discharge circuit, receives described
First output signal, its output end connects the BUCK constant-current drive circuits, and the photo-coupler is by first output signal
It is enlarged into after the second output signal, is driven second output signal as the feedback signal back to the BUCK constant currents
Circuit.
3. constant current output circuit according to claim 2, it is characterised in that
The voltage signal and reference signal are compared by the discharge circuit according to comparison rule, if comparative result is described
Voltage signal is more than the reference signal, then the first output signal exported from the discharge circuit output end reduces；If comparing
As a result it is less than the reference signal for the voltage signal, then the first output signal exported from the discharge circuit output end increases
Greatly.
4. the constant current output circuit according to Claims 2 or 3, it is characterised in that the constant current feedback circuit also includes dividing
Piezoresistance, wherein,
The divider resistance connects the input of the discharge circuit output end and the photo-coupler respectively, wherein, described
One output signal is voltage signal；
The first output signal that the divider resistance is exported to the discharge circuit carries out partial pressure, obtains partial pressure switch signal, and
The partial pressure switch signal is inputted to the input of the photo-coupler.
5. constant current output circuit according to claim 4, it is characterised in that
The photo-coupler, is received using its input and first output signal progress partial pressure is obtained by the divider resistance
Partial pressure switch signal, and the partial pressure switch signal is enlarged into after the second output signal, second output signal is made
For the feedback signal back to the BUCK constant-current drive circuits.
6. constant current output circuit according to claim 5, it is characterised in that
If first output signal of the discharge circuit output reduces, the partial pressure switch letter that the divider resistance partial pressure is obtained
Number increase, then second output signal increase；
If first output signal increase of the discharge circuit output, the partial pressure switch letter that the divider resistance partial pressure is obtained
Number reduce, then second output signal reduces.
7. constant current output circuit according to claim 2, it is characterised in that the BUCK constant-current drive circuits include first
Sampling resistor, control IC and switch, wherein
The current signal respectively loaded is passed through in first sampling resistor, collection, and the current signal is converted into voltage letter
Exported after number to an input of the discharge circuit；
The control IC, with input and output end, its input connects the output end of the photo-coupler, receives the light
The feedback signal of coupler feedback, its output end connects the switch, and the control IC is using the feedback signal according to control
The ON time switched described in rule control, and make the ON time control in default maximum ON time, utilize institute
Size of current of the ON time length adjustment of switch Jing Guo the load is stated, to ensure the constant of each load current.
8. constant current output circuit according to claim 7, it is characterised in that the discharge circuit includes operational amplifier,
Wherein,
The operational amplifier has anode and negative terminal, and the negative terminal connects first sampling resistor, and the anode receives institute
State reference signal.
9. the constant current output circuit according to claim 7 or 8, it is characterised in that
If the feedback signal that the control IC is received reduces, the switch conduction is controlled, the load is flowed through to increase
Electric current, and the switch conduction times reach the default maximum ON time when control described in switch off；
If the feedback signal increase that the control IC is received, switch off to reduce the conducting of the switch described in control
Time, reduce the electric current for flowing through the load.
10. the constant current output circuit according to any one of claims 1 to 3, it is characterised in that
The BUCK constant-current drive circuits include inductance component and the second sampling resistor, and the switch includes metal-oxide-semiconductor, the MOS
The drain electrode of pipe is connected through the inductance component with first sampling resistor, and grid connects the control IC, source electrode and described the
Two sampling resistors are connected.
11. the constant current output circuit according to any one of claims 1 to 3, it is characterised in that the load includes light source.
12. a kind of lighting device, it is characterised in that including：
Constant current output circuit as any one of claim 1-11；
Multiple light sources, are connected, the multiple light source is by the perseverance with the BUCK constant-current drive circuits in the constant current output circuit
Flow output circuit and constant current is provided.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201710566411.0A CN107277978A (en) | 2017-07-12 | 2017-07-12 | A kind of constant current output circuit and lighting device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201710566411.0A CN107277978A (en) | 2017-07-12 | 2017-07-12 | A kind of constant current output circuit and lighting device |
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| CN107277978A true CN107277978A (en) | 2017-10-20 |
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| CN201710566411.0A Pending CN107277978A (en) | 2017-07-12 | 2017-07-12 | A kind of constant current output circuit and lighting device |
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