CN103108432B - LED driver and the LED light device with this LED driver - Google Patents
LED driver and the LED light device with this LED driver Download PDFInfo
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- CN103108432B CN103108432B CN201110358157.8A CN201110358157A CN103108432B CN 103108432 B CN103108432 B CN 103108432B CN 201110358157 A CN201110358157 A CN 201110358157A CN 103108432 B CN103108432 B CN 103108432B
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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
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The present invention relates to a kind of LED driver, for driving the first load group (S1) and the load branch of at least one the second load group (S2) including being one another in series, wherein, LED driver includes: be the first load group (S1) and PFC AC/DC change-over circuit (1) of the intended running voltage (Vb) of the second load group (S2) offer；Switch control unit (3)；And at least one switch element (2), wherein, switch element (2) is in parallel with respective described second load group (S2), switch control unit (3) exports the first control signal (Ctrl_1) according to the first sampled voltage (Vs_1) characterizing the load current (I_s) flowing through load branch to switch element (2), to adjust switch element (2) conducting state, thus change the electric current (I_s2) flowing through the second load group (S2).Moreover, it relates to the LED light device of a kind of LED driver with the above-mentioned type.
Description
Technical field
The present invention relates to a kind of LED driver.Moreover, it relates to a kind of LED illumination with this LED driver
Device.
Background technology
LED light source has photochromic pure, light beam concentration, color rendering index height, good temp characteristic as cold light source, and has electricity
The advantages such as amount consumption is low, stable performance, life-span length, pollution-free, use is simple.In order to LED light source is driven, market goes out
Show substantial amounts of dissimilar AC-DC LED driver, including the PFC driver of single-stage, the pwm driver of two-stage, passed
The Linear actuator of system and the switch element being used for LED chain etc..But they are respectively provided with different pluses and minuses.Such as,
Single-stage PFC activation configuration is simple, with low cost, can provide good power factor, but it has bigger ripple electricity
Stream.Two-stage pwm driver can provide high power factor and low ripple current, but its structure is complicated, cost is high, and
Electromagnetic interference source has two high frequencies, and capacity of resisting disturbance is poor.The simple in construction of traditional Linear actuator, with low cost, but
It is inefficient and power factor is relatively low.And the simplest for the structure of the switch element of LED chain, cost is minimum, energy
Good power factor is enough provided, high-tension application scheme has good efficiency, and capacity of resisting disturbance is very strong, but
It is that it produces the highest ripple current.
Summary of the invention
For solving above-mentioned technical problem, the present invention proposes a kind of LED driver, this LED driver set prior art
In all advantages of driver, its simple in construction, with low cost, there is high power factor and efficiency, capacity of resisting disturbance is more
By force, and it produces less ripple current.In addition the invention still further relates to the LED of a kind of LED driver with the above-mentioned type
Illuminator.
First purpose of the present invention is achieved in by a kind of LED driver, and i.e. this LED driver is for driving each other
First load group of series connection and at least one second load group, this LED driver includes: be the first load group and the second load group
The PFC-AC/DC change-over circuit of intended running voltage is provided；Switch control unit；And at least one switch element, wherein,
Switch element is in parallel with respective second load group, and switch control unit is according to characterizing the of the load current flowing through load branch
One sampled voltage exports the first control signal to switch element, to adjust switching means conductive state, thus changes and flows through second
The electric current of load group.LED driver according to the present invention have employed PFC-AC/DC change-over circuit and the combination side of switch element
Formula, is obtained in that the output voltage with high power factor by PFC-AC/DC change-over circuit.In the design according to the present invention
In scheme, PFC-AC/DC change-over circuit can be any type of pfc circuit.Such as BUCK PFC.PFC-AC/DC changes electricity
Road can control IC or MCU by traditional PFC and control.In this way, it is possible to obtain high power factor.PFC-
The output voltage of AC/DC change-over circuit is direct current.The average voltage controlled by pfc circuit has the highest precision.But,
Inevitable that AC portion exists in this DC source, according to the V-I characteristic of LED light source, di/dv is the highest, for
Little dv, the change of electric current is very violent, and this will cause high ripple current.By controlling the LED driver according to the present invention
In the conducting state of switch element the electric current flowing through the second load group can be adjusted, thus change and flow through load group
Electric current, to reach to eliminate the purpose of ripple current.
Design according to the present invention proposes, and PFC-AC/DC change-over circuit includes the power exporting described running voltage
Factor correcting part and feedback control unit, feedback control unit is according to the second reference voltage utilizing the first sampled voltage to obtain
The second sampled voltage that the running voltage currently exported with power factor correction portion obtains produces the second control signal, power because of
Number correction portion is according to the described second intended running voltage of control signal output.PFC-AC/DC conversion electricity according to the present invention
Road can be any type of pfc circuit, but some control models can not control pfc circuit, such as, some DCM well
Pfc circuit only secures the dutycycle in each working cycle, and each linear period adjusts a PFC output averagely
Voltage.Its structure is very simple, but the PFC average voltage of output is not the most accurate.The bigger tolerance of PFC output voltage
LED current will be affected.Therefore the running voltage of PFC-AC/DC change-over circuit output is a parameter the most crucial.By root
Well the running voltage of output can be controlled at one according to the PFC-AC/DC change-over circuit in the LED driver of the present invention
In acceptable zone of reasonableness, it is possibly realized so that eliminating ripple current.
A preferred design according to the present invention proposes, and switch control unit includes the first operational amplifier, its
In-phase input end accesses the first reference voltage preset, and inverting input accesses the first sampled voltage, and outfan is connected to switch
Unit, adjusts according to the control voltage as the first control signal that the first sampled voltage and the first default reference voltage calculate
The conducting state of whole switch element.The electric current flowing through the second load group can be carried out by the conducting state changing switch element
Adjust, thus change the voltage in load group, and then change the electric current flowing through load group, to reach to eliminate the mesh of ripple current
's.
Preferably, switch control unit also includes second, third resistance, wherein, described second resistance and the 3rd resistance
Being connected in series between supply voltage and ground, the in-phase input end of described first operational amplifier is connected to the second resistance and the 3rd
Node between resistance.In the design of the present invention, this supply voltage can be taken from and carry out PFC AC/DC change-over circuit
IC or MCU controlled, naturally it is also possible to be independent supply voltage.Big by adjusting the resistance of the second resistance and the 3rd resistance
The little value determining reference voltage.
It may further be preferable that switch control unit also includes the 4th resistance and the first electric capacity, it connects in series with each other
Between the inverting input and outfan of the first operational amplifier, at the inverting input of the first operational amplifier and defeated
Go out and between end, constitute a feedback circuit.
Advantageously, switch control unit also includes that the 5th resistance, one end of the 5th resistance are connected to the first computing and put
Node between inverting input and first electric capacity of big device, the other end of the 5th resistance is connected to the outfan of load branch.
5th resistance and the second resistance mate, to improve the capacity of resisting disturbance of control unit.
It is proposed, according to the invention, that LED driver also includes that the 6th resistance, the 6th resistance are connected to the other end of the 5th resistance
And second load group outfan between node and ground between.Basis is may determine that by the resistance size selecting the 6th resistance
Flow through the size of the first sampled voltage of the load current calculating of load branch.
Preferably, switch element includes a MOSFET pipe, and wherein, the drain electrode of a MOSFET pipe is connected to as the
The positive pole of the LED light emitting diode of two load group, source electrode is connected to the negative pole of described LED light emitting diode, and grid is connected to
Node between outfan and the 4th resistance of one operational amplifier.Adjusted by the control voltage as the first control signal
The conducting state of the oneth MOSFET pipe, thus adjust the size of current flowing through a MOSFET pipe.Due to LED light emitting diode with
Oneth MOSFET pipe is in parallel, and the electric current therefore flowing through LED light emitting diode also changes, thus causes LED light emitting diode
Voltage also change, and then guarantee that the AC portion in running voltage is consumed by the second load group, to guarantee first
Load group, with dc voltage operation, reaches to eliminate the purpose of ripple current in the first load group.
It may further be preferable that switch element also includes that the first diode, the positive pole of the first diode are connected to the first fortune
Calculating the node between outfan and the 4th resistance of amplifier, negative pole is connected to the grid of a MOSFET pipe.One or two pole
Pipe is used for preventing electric current to be back to the first operational amplifier from a MOSFET pipe.
Additionally, it is further proposed that switch element also includes the first resistance, one end of this first resistance is connected to first
Node between grid and the negative pole of the first diode of MOSFET pipe, and the other end is connected to the source electrode of a MOSFET pipe
And the node between the negative pole of LED light emitting diode.This creates one between grid and the source electrode of a MOSFET pipe and puts
Electricity loop, thus play the effect of protection the oneth MOSFET pipe.
Preferred design according to the present invention proposes, power factor correction portion include the 2nd MOSFET pipe,
Inductance, the second electric capacity, the second diode, wherein, the drain electrode of the 2nd MOSFET pipe is connected to the live wire of alternating current power supply, and source electrode connects
To one end of described inductance, grid is connected to feedback control unit, and the other end of inductance is connected to PFC-AC/DC change-over circuit
Outfan, one end of the second electric capacity is connected to the node between the other end of inductance and the outfan of power factor correction portion,
Other end ground connection, the negative pole of the second diode is connected to the node between source electrode and one end of inductance of the 2nd MOSFET pipe, just
Pole is connected to the node between the other end and the ground of the second electric capacity.Believe by adjusting the control that the 2nd MOSFET pipe is controlled
Number dutycycle, the power factor correction portion intended running voltage of output can be made.
Preferably, feedback control unit includes that the second operational amplifier, PFC control circuit and reference voltage occur electricity
Road, the in-phase input end of the second operational amplifier is connected to the outfan of reference voltage generating circuit, reference voltage generating circuit
Input be connected to the outfan of the second load group, inverting input is connected to the outfan of power factor correction portion,
The outfan of two operational amplifiers is connected to the input of PFC control circuit, and the grid of the 2nd MOSFET pipe is connected to PFC
The outfan of control circuit.Reference voltage generating circuit receives the first sampled voltage, and by this first sampled voltage with preset
Threshold value compares, and exports the second reference voltage, the second operational amplifier root when the first sampled voltage is more than the threshold value preset
Calculate according to the second reference voltage and the second sampled voltage obtained from the running voltage that PFC-AC/DC change-over circuit currently exports
Obtain the second control voltage.PFC control circuit controls voltage output according to second and have adjusted the second control signal of dutycycle, should
2nd MOSFET pipe is controlled by control signal, so that the intended running voltage of power factor correction portion output.
It may further be preferable that quantity N of the LED light emitting diode in the first load group can be obtained by below equation,
I.e. N=Vdc/Vf, wherein Vdc is the DC voltage of PFC-AC/DC change-over circuit output, and Vf is the forward of LED light emitting diode
Voltage.Quantity M of the LED light emitting diode in the second load group can be obtained by below equation, i.e. M=Vacp-p/Vf, wherein
Vacp-p is the AC portion in the running voltage of PFC-AC/DC change-over circuit output, and Vf is the forward electricity of LED light emitting diode
Pressure.
Another object of the present invention is achieved in by a kind of LED light device, i.e. this LED light device has above-mentioned class
The LED driver of type.The output of the LED light device according to the present invention is more stable, simultaneously simple in construction, with low cost.
Accompanying drawing explanation
Accompanying drawing constitutes the part of this specification, is adapted to assist in and is further appreciated by the present invention.These accompanying drawings illustrate this
Bright embodiment, and it is used for illustrating the principle of the present invention together with description.The most identical parts are with identical label
Represent.Shown in figure:
Fig. 1 is the oscillogram of the running voltage of the PFC AC/DC change-over circuit output of the LED driver according to the present invention；
Fig. 2 is the theory diagram of the LED driver according to the present invention；
Fig. 3 is the circuit diagram of the LED driver according to the present invention.
Detailed description of the invention
Fig. 1 shows the oscillogram of the running voltage of the PFC AC/DC change-over circuit output of the LED driver of the present invention.
It can be seen that running voltage Vb of PFCAC/DC change-over circuit output is not entirely DC voltage, this running voltage Vb is
It is made up of direct current component Vdc and AC portion Vacp-p.Wherein running voltage minima is Vbmin=Vdc (1)；Maximum
It is Vbmax=Vdc+Vacp-p (2).The most as shown in Figure 1, time dependent running voltage Vb (t)=Vdc+Vac (t)
(3).The purpose of the present invention is that the elimination ripple voltage impact on the first load group.
Fig. 2 is the theory diagram of the LED driver according to the present invention.It can be seen that according to the LED driver of the present invention
Drive the first load group S1 of being one another in series and at least one second load group S2, in the present embodiment, load group S1 and S2 by
At least one LED light emitting diode is constituted, the LED luminescence two that wherein can determine in the first load group S1 according to below equation
Quantity N of pole pipe, i.e. N=Vdc/Vf, wherein Vdc is the DC voltage of PFC-AC/DC change-over circuit 1 output, and Vf is that LED is luminous
The forward voltage of diode, and the number of LED light emitting diode in the second load group S2 can be determined according to below equation
Amount M can be obtained by below equation, i.e. M=Vacp-p/Vf, and wherein Vacp-p is the work of PFC-AC/DC change-over circuit 1 output
AC portion in voltage, Vf is the forward voltage of LED light emitting diode.In the present embodiment, for convenience, Mei Ge
Two load group S2 only include a LED light emitting diode DL11；...；DLm1, certain second load group S2 can also be as required
Include the LED light emitting diode of varying number respectively.
Further it can be seen in fig. 2 that LED driver includes providing intended for the first load group S1 and the second load group S2
The PFC-AC/DC change-over circuit 1 of running voltage Vb；Switch control unit 3；And at least one switch element 2, wherein, switch
Unit 2 is in parallel with respective second load group S2, and switch control unit 3 flows through the load current I_s of load branch according to characterizing
The first sampled voltage Vs_1 export the first control signal Ctrl_1 to switch element 2, to adjust switch element 2 conducting state,
Thus change the electric current I_s2 flowing through the second load group S2.In the present embodiment, the quantity of switch element 2 and the second load group S2
Quantity equal.Additionally, it can be seen in fig. 2 that PFC-AC/DC change-over circuit 1 includes the power factor school of output services voltage Vb
Positive part 5 and feedback control unit 4, the first sampled voltage Vs_1 is compared by this feedback control unit 4, at the first sampling electricity
When pressure Vs_1 exceedes default threshold value, export the second reference voltage Vref _ 2.Feedback control unit 4 is according to this second reference voltage
Vref_2 and the second sampled voltage Vs_2 obtained from running voltage Vb_1 that power factor correction portion 5 currently exports produces
Second control signal Ctrl_2, power factor correction portion 5 is according to the second intended running voltage of control signal Ctrl_2 output
Vb。
Fig. 3 is the circuit diagram of the LED driver according to the present invention.It can be seen that switch control unit 3 includes the first fortune
The in-phase input end calculating amplifier X1, the first operational amplifier X1 accesses the first reference voltage Vref _ 1 preset, anti-phase input
Terminating into the first sampled voltage Vs_1, outfan X1_out is connected to switch element 2, according to the first sampled voltage Vs_1 with default
The Vg_1 as the first control signal Ctrl_1 first that calculates of the first reference voltage Vref _ 1 control voltage Vg_1 and adjust
The conducting state of switch element 2, wherein, switch control unit 3 also includes the second resistance R2 and the 3rd resistance R3, wherein, second
Resistance R2 and the 3rd resistance R3 is connected in series between supply voltage Vcc and ground, the in-phase input end of the first operational amplifier X1
It is connected to the node between the second resistance R2 and the 3rd resistance R3.Furthermore, it can be seen that switch control unit 3 also includes from figure
Four resistance R4 and the first electric capacity C1, the 4th resistance R4 and the first electric capacity C1 are connected to the first operational amplifier X1's in series with each other
Between inverting input and outfan X1_out.Additionally, switch control unit 3 also includes the 5th resistance R5, the 5th resistance R5's
One end is connected to the node between the inverting input of the first operational amplifier X1 and the first electric capacity C1, another of the 5th resistance R5
End is connected to the outfan of load branch.
Additionally, according to the driver of the present invention also including, the 6th resistance R6, the 6th resistance R6 are connected to the 5th resistance
Between node and ground between the other end and the outfan of the second load group S2 of R5.
The most as can be seen from Fig. 3, switch element 2 includes a MOSFET pipe Q11；...；Q1m, wherein, first
MOSFET pipe Q11；...；The drain electrode of Q1m is connected to the LED light emitting diode DL11 as the second load group S2；...；DLm1's
Positive pole, source electrode is connected to LED light emitting diode DL11；...；The negative pole of DLm1, grid is connected to the first operational amplifier X1's
Node between outfan X1_out and the 4th resistance R4, and switch element 2 also includes the first diode D11；...；D1m,
First diode D11；...；The positive pole of D1m be connected to the first operational amplifier X1 outfan X1_out and the 4th resistance R4 it
Between node, negative pole is connected to a MOSFET pipe Q11；...；The grid of Q1m.Additionally, switch element 2 also includes the first resistance
R11；...；R1m, the first resistance R11；...；One end of R1m is connected to a MOSFET pipe Q11；...；The grid of Q1m and
One diode D11；...；Node between the negative pole of D1m, and the other end is connected to a MOSFET pipe Q11；...；Q1m's
Source electrode and LED light emitting diode DL11；...；Node between the negative pole of DLm1.
Show the circuit diagram of PFC-AC/DC change-over circuit 1 in the left side of the circuit diagram shown in Fig. 3, this PFC-AC/DC turns
Changing circuit 1 and include power factor correction portion 5 and the feedback control unit 4 of routine, wherein power factor correction portion 5 includes
2nd MOSFET pipe Qp, inductance L1, the second electric capacity C2, the second diode D2, wherein, the drain electrode of the 2nd MOSFET pipe Qp is connected to
The live wire of alternating current power supply, source electrode is connected to one end of inductance L1, and grid is connected to feedback control unit 4, the other end of inductance L1
Being connected to the outfan Out_pfc of PFC-AC/DC change-over circuit 1, one end of described second electric capacity C2 is connected to the another of inductance L1
Node between the outfan of one end and power factor correction portion 5, other end ground connection, the negative pole of the second diode D2 is connected to
Node between source electrode and one end of inductance L1 of 2nd MOSFET pipe Qp, positive pole is connected to the other end and the ground of the second electric capacity C2
Between node.
In the design of the present invention, feedback control unit 4 can be conventional A/D converter, and it is sampled first
Exporting after voltage conversion to controller, this controller adjusts the dutycycle to the signal that the 2nd MOSFET pipe is controlled, from
And reach the purpose making PFC AC/DC change-over circuit 1 export intended running voltage.A specific embodiment in the present invention
In, feedback control unit 4 includes the second operational amplifier X2, PFC control circuit 6 and reference voltage generating circuit 7, the second fortune
The in-phase input end calculating amplifier X2 is connected to the outfan of reference voltage generating circuit 7, the input of reference voltage generating circuit 7
End is connected to the outfan of the second load group S2, and inverting input is connected to the outfan of power factor correction portion 5, the second fortune
The outfan X2_out calculating amplifier X2 is connected to the input of PFC control circuit 6, and the grid of the 2nd MOSFET pipe Qp is even
It is connected to the outfan of PFC control circuit 6.Reference voltage generating circuit 7 receives the first sampled voltage Vs_1, and by this first sampling
Voltage Vs_1 compares with the threshold value preset, and when the first sampled voltage Vs_1 is more than the threshold value preset, output second is with reference to electricity
Pressure Vref_2, the second operational amplifier X2 currently export according to the second reference voltage Vref _ 2 with from PFC-AC/DC change-over circuit 1
Running voltage Vb_1 on obtain second sampled voltage Vs_2 calculate obtain second control voltage Vg_2.PFC control circuit 6
Control voltage Vg_2 output according to second and have adjusted the second control signal Ctrl_2 of dutycycle, this second control signal Ctrl_2 pair
2nd MOSFET pipe Qp is controlled, so that power factor correction portion 5 exports intended running voltage Vb.
In the actual motion according to the LED driver of the present invention, by PFC-AC/DC change-over circuit 1 output, there is height
The output voltage Vb, this output voltage Vb of power factor directly drive LED, according to the V-I characteristic of LED, di/dv is the highest,
For little dv, the change of electric current is the most dramatic, and this will cause high ripple current.In order to process this ripple voltage, some
LED current and voltage are controlled.According to relational expression (3), Vb (t)=Vdc+Vac (t).Voltage in first load group S1 is about
For Vdc, its Chang Liang.Electric current and the voltage of the second load group S2 are controlled.In the design of the present invention, the 2nd MOSFET pipe with
Second load group S2 is connected in parallel, and connects LED current with bypass.
In actual work, as Vb=Vdc, only the LED in the first load group S1 lights.In the first load
LED light emitting diode D11 in group S1 ..., the forward voltage of D1n is Vf, and the electric current of LED light emitting diode is restricted to want
Ask.Supply voltage Vcc is the DC signal providing energy for operational amplifier X2.First reference voltage Vref can be DC signal or
Person's DC signal is compound with AC signal.This depends on requirement.When LED current is restricted to require, the first reference voltage Vref
With the first sampled voltage Vs_1 that the 6th resistance R6 may be designed so that the 6th resistance R6 less than the first reference voltage Vref, the
The output first of one operational amplifier X1 controls voltage Vg_1 for height, then an all of MOSFET pipe Q1-Qn connects.
As Vdc ＜ Vb ＜ Vdc+Vf, the first and second load group S1, the voltage of S2 rises, and this causes higher electric current.
First sampled voltage Vs_1 also rises.According to the difference of Vref and Vs, the first control voltage Vg_ of the first operational amplifier X1 output
1 will decline.The electric current of the oneth MOSFET pipe Q1 declines, the LED light-emitting diodes that remaining electric current will flow through in the second load group S2
Pipe DL11.The voltage of the first load group S1 is maintained at the LED luminescence two that Vdc and other voltage will add in the second load group S2
Pole pipe DL11.As Vb=Vdc+Vf, a MOSFET pipe Q1 disconnects and the electric current of LED light emitting diode DL11 and first negative
Electric current in load group S1 is identical.
As Vdc+Vf ＜ Vb ＜ Vdc+2*Vf, the voltage of the first load group S1 and LED light emitting diode DL11 is higher than Vdc
+ Vf, electric current rises.First sampled voltage Vs_1 also rises.According to the difference of Vref and Vs, the of the first operational amplifier X1 output
One controls voltage Vg_1 will decline.The electric current of the oneth MOSFET pipe Q1 declines, and remaining electric current will flow through the second other load
LED light emitting diode DL21 in group S2.The voltage of the first load group S1 and LED light emitting diode DL11 is maintained at Vdc+Vf also
And the LED light emitting diode DL21 that other voltages will add in the second other load group S2.As Vb=Vdc+2*Vf, additionally
A MOSFET pipe Q2 disconnect and the electric current of LED light emitting diode DL21 and the electric current of the first load group S1 and LED luminescence
The electric current of diode DL11 is identical.
When Vb persistently rises, a MOSFET pipe will disconnect one by one, and LED current will flow sequentially through
DL31, DL41......DLml, so that it is guaranteed that the electric current in the first load group S1 keeps constant.
PFC-AC/DC change-over circuit 1 according to the present invention can be any type of pfc circuit.Such as BUCK PFC.
PFC-AC/DC change-over circuit 1 can be controlled by traditional IC or MCU.But some control models can not be controlled well
Pfc circuit processed, such as, some DCMPFC circuit only secure the dutycycle in each working cycle, and adjust each
The PFC of one time of linear period exports average voltage.Its structure is very simple, but the PFC average voltage of output is not
It is the most accurate.The bigger tolerance of PFC output voltage will affect LED current.Therefore the work of PFC-AC/DC change-over circuit output
Voltage is a parameter the most crucial.In the design of the present invention, when detecting that sign flows through the load of load branch
When the first sampled voltage Vs_1 of electric current I_s exceedes default threshold value, the second reference voltage Vref _ 2 will be produced to feedback control
Unit 4 processed.In the present embodiment, the second operational amplifier X2 of feedback control unit 4 is according to the second reference voltage Vref _ 2 He
The the second sampled voltage Vs_2 obtained from the running voltage that PFC-AC/DC change-over circuit currently exports calculates and obtains the second control
Voltage Vg_2, and the second control signal Ctrl_2 controlling voltage Vg_2 output adjustment dutycycle according to second, this control signal
2nd MOSFET pipe Qp is controlled by Ctrl_2, so that power factor correction portion 5 exports intended running voltage Vb.
These are only the preferred embodiments of the present invention, be not limited to the present invention, for those skilled in the art
For Yuan, the present invention can have various modifications and variations.All made within the spirit and principles in the present invention any amendment, etc.
With replacement, improvement etc., should be included within the scope of the present invention.
Reference number
1 PFC-AC/DC change-over circuit
2 switch elements
3 switch control units
4 feedback control units
5 power factor correction portion
6. PFC control circuit
7 reference voltage generating circuits
X1 the first operational amplifier
X2 the second operational amplifier
R11；...；R1m the first resistance
R2 the second resistance
R3 the 3rd resistance
R4 the 4th resistance
R5 the 5th resistance
R6 the 6th resistance
C1 the first electric capacity
C2 the second electric capacity
D11；...；D1m the first diode
D2 the second diode
Q11；...；Q1m the oneth MOSFET manages
Qp the 2nd MOSFET manages
L1 inductance
S1 the first load group
S2 the second load group
D11 ..., the LED light emitting diode in D1n the first load group S1
DL11；...；The LED light emitting diode of DLm1 the second load group S2
Vcc supply voltage
Running voltage expected from Vb
The running voltage that Vb_1 currently exports
Vs_1 the first sampled voltage
Vs_2 the second sampled voltage
Vg_1 first controls voltage
Vg_2 second controls voltage
The forward voltage of Vf LED light emitting diode
The DC voltage of Vdc PFC-AC/DC change-over circuit output
AC portion in the running voltage of Vacp-p PFC-AC/DC change-over circuit output
The first reference voltage that Vref_1 presets
Vref_2 the second reference voltage
I_s flows through the load current of load branch
I_s2 flows through the electric current of the second load group S2
Ctrl_1 the first control signal
Ctrl_2 the second control signal
The outfan of X1_out the first operational amplifier X1
The outfan of X2_out the second operational amplifier X2
The outfan of Out_pfc PFC-AC/DC change-over circuit
Claims (15)
1. a LED driver, for driving the first load group (S1) and at least one the second load group including being one another in series
(S2) load branch, it is characterised in that described LED driver includes: for described first load group (S1) and the second load group
(S2) the PFC-AC/DC change-over circuit (1) of intended running voltage (Vb) is provided；Switch control unit (3)；And at least one
Switch element (2), wherein, described switch element (2) is in parallel with respective described second load group (S2), described on-off control list
Unit (3) is single to described switch according to the first sampled voltage (Vs_1) characterizing the load current (I_s) flowing through described load branch
Unit (2) exports the first control signal (Ctrl_1), and to adjust described switch element (2) conducting state, thus change is flow through described
The electric current (I_s2) of the second load group (S2).
LED driver the most according to claim 1, it is characterised in that described PFC-AC/DC change-over circuit (1) includes defeated
Go out power factor correction portion (5) and feedback control unit (4), the described feedback control list of described intended running voltage (Vb)
Unit (4) is according to the second reference voltage (Vref_2) utilizing described first sampled voltage (Vs_1) to obtain with from described power factor
The second sampled voltage (Vs_2) that the running voltage (Vb_1) of correction portion (5) currently output obtains produces the second control signal
(Ctrl_2), described power factor correction portion (5) exports described intended work according to described second control signal (Ctrl_2)
Make voltage (Vb).
LED driver the most according to claim 1, it is characterised in that described switch control unit (3) includes the first computing
Amplifier (X1), the in-phase input end of described first operational amplifier (X1) accesses the first reference voltage (Vref_1) preset,
Inverting input accesses described first sampled voltage (Vs_1), and outfan (X1_out) is connected to described switch element (2), according to
Described in the conduct that described first sampled voltage (Vs_1) and the first reference voltage (Vref_1) preset calculate, first controls letter
First control voltage (Vg_1) of number (Ctrl_1) adjusts the conducting state of described switch element (2).
LED driver the most according to claim 3, it is characterised in that described switch control unit (3) also includes the second electricity
Resistance (R2) and the 3rd resistance (R3), wherein, described second resistance (R2) and the 3rd resistance (R3) are connected in series in supply voltage
(Vcc) and between ground, the in-phase input end of described first operational amplifier (X1) is connected to described second resistance (R2) and the 3rd
Node between resistance (R3).
LED driver the most according to claim 4, it is characterised in that described switch control unit (3) also includes the 4th electricity
Resistance (R4) and the first electric capacity (C1), described 4th resistance (R4) and described first electric capacity (C1) are connected to described the in series with each other
Between inverting input and the outfan (X1_out) of one operational amplifier (X1).
LED driver the most according to claim 5, it is characterised in that described switch control unit (3) also includes the 5th electricity
Resistance (R5), one end of described 5th resistance (R5) is connected to the inverting input and described the of described first operational amplifier (X1)
Node between one electric capacity (C1), the other end of described 5th resistance (R5) is connected to the outfan of described load branch.
LED driver the most according to claim 6, it is characterised in that described LED driver also includes the 6th resistance
(R6), described 6th resistance (R6) is connected to the other end and the output of described second load group (S2) of described 5th resistance (R5)
Between node and ground between end.
LED driver the most according to claim 6, it is characterised in that described switch element (2) includes a MOSFET pipe
(Q11；…；Q1m), wherein, a described MOSFET manages (Q11；…；Q1m) drain electrode is connected to as described second load group
(S2) LED light emitting diode (DL11；…；DLm1) positive pole, source electrode is connected to described LED light emitting diode (DL11；…；
DLm1) negative pole, grid is connected to the outfan (X1_out) of described first operational amplifier (X1) and described 4th resistance
(R4) node between.
LED driver the most according to claim 8, it is characterised in that described switch element (2) also includes the first diode
(D11；…；D1m), described first diode (D11；…；D1m) positive pole is connected to the defeated of described first operational amplifier (X1)
Going out the node between end (X1_out) and described 4th resistance (R4), negative pole is connected to a described MOSFET and manages (Q11；…；
Q1m) grid.
LED driver the most according to claim 9, it is characterised in that described switch element (2) also includes the first resistance
(R11；…；R1m), described first resistance (R11；…；R1m) one end is connected to a described MOSFET and manages (Q11；…；Q1m)
Grid and described first diode (D11；…；D1m) the node between negative pole, and the other end is connected to described first
MOSFET manages (Q11；…；Q1m) source electrode and described LED light emitting diode (DL11；…；DLm1) the node between negative pole.
11. LED drivers according to claim 2, it is characterised in that described power factor correction portion (5) includes
Two MOSFET manage (Qp), inductance (L1), the second electric capacity (C2), the second diode (D2), wherein, described 2nd MOSFET pipe (Qp)
Drain electrode be connected to the live wire of alternating current power supply, source electrode is connected to one end of described inductance (L1), and grid is connected to described feedback control
Unit processed (4), the other end of described inductance (L1) is connected to the outfan (Out_ of described PFC-AC/DC change-over circuit (1)
Pfc), one end of described second electric capacity (C2) is connected to the other end of described inductance (L1) and described power factor correction portion
(5) the node between outfan, other end ground connection, the negative pole of described second diode (D2) is connected to described 2nd MOSFET
Node between source electrode and one end of described inductance (L1) of pipe (Qp), positive pole is connected to the other end of described second electric capacity (C2)
And the node between ground.
12. LED drivers according to claim 11, it is characterised in that described feedback control unit (4) includes the second fortune
Calculate amplifier (X2), PFC control circuit (6) and reference voltage generating circuit (7), described second operational amplifier (X2) same
Phase input is connected to the outfan of described reference voltage generating circuit (7), the input of described reference voltage generating circuit (7)
Being connected to the outfan of described second load group (S2), inverting input is connected to the defeated of described power factor correction portion (5)
Going out end, the outfan (X2_out) of described second operational amplifier (X2) is connected to the input of described PFC control circuit (6),
And the grid of described 2nd MOSFET pipe (Qp) is connected to the outfan of described PFC control circuit (6).
13. LED drivers according to any one of claim 1 to 10, it is characterised in that described first load group (S1)
In quantity N of LED light emitting diode can be obtained by below equation, i.e. N=Vdc/Vf, wherein Vdc is described PFC-AC/DC
The DC voltage that change-over circuit (1) exports, Vf is the forward voltage of described LED light emitting diode.
14. LED drivers according to any one of claim 1 to 10, it is characterised in that described second load group (S2)
In quantity M of LED light emitting diode can be obtained by below equation, i.e. M=Vacp-p/Vf, wherein Vacp-p is described
AC portion in the running voltage that PFC-AC/DC change-over circuit (1) exports, Vf is the forward electricity of described LED light emitting diode
Pressure.
15. 1 kinds of LED light device, it is characterised in that described LED light device has according to arbitrary in claim 1 to 14
LED driver described in Xiang.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110358157.8A CN103108432B (en) | 2011-11-11 | 2011-11-11 | LED driver and the LED light device with this LED driver |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110358157.8A CN103108432B (en) | 2011-11-11 | 2011-11-11 | LED driver and the LED light device with this LED driver |
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| Publication Number | Publication Date |
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| CN103108432A CN103108432A (en) | 2013-05-15 |
| CN103108432B true CN103108432B (en) | 2016-09-14 |
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| CN103716968A (en) * | 2014-01-09 | 2014-04-09 | 合肥云杉光电科技有限公司 | Road illumination method with direct-current high-voltage direct-driven LEDs converted through three-phase alternating current electric supply |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101431845A (en) * | 2007-11-05 | 2009-05-13 | 深圳桑达百利电器有限公司 | Driving method and circuit for LED lamp string |
| CN101789684A (en) * | 2010-03-05 | 2010-07-28 | 于锁平 | Power factor corrector |
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| TWI495389B (en) * | 2008-09-05 | 2015-08-01 | Eldolab Holding Bv | Led based lighting application |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101431845A (en) * | 2007-11-05 | 2009-05-13 | 深圳桑达百利电器有限公司 | Driving method and circuit for LED lamp string |
| CN101789684A (en) * | 2010-03-05 | 2010-07-28 | 于锁平 | Power factor corrector |
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