CN104822199B - The current balance control circuit and control method of a kind of LED multi-path lamp string - Google Patents
The current balance control circuit and control method of a kind of LED multi-path lamp string Download PDFInfo
- Publication number
- CN104822199B CN104822199B CN201510192386.5A CN201510192386A CN104822199B CN 104822199 B CN104822199 B CN 104822199B CN 201510192386 A CN201510192386 A CN 201510192386A CN 104822199 B CN104822199 B CN 104822199B
- Authority
- CN
- China
- Prior art keywords
- signal
- circuit
- current
- lamp string
- reference voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The invention discloses the current balance control circuits and control method of a kind of LED multi-path lamp string, by the way that the LED light string all the way of pressure drop maximum is used linear regulation pattern, remaining each road uses pwm pattern, after PWM control modes, only has the conduction voltage drop of switching tube during the work time, loss is reduced to zero between when off, can improve system effectiveness compared with the prior art.And, the reference voltage signal of feedback control circuit is arranged to by the present invention can be according to the size of actual conditions automatic adjusument reference voltage signal, the output voltage that may be such that power stage circuit is the minimum value that can guarantee LED light string normal work, and system effectiveness is further enhanced.
Description
Technical field
The present invention relates to field of power supplies, a kind of current balance control circuit more specifically to LED multi-path lamp string and
Control method.
Background technology
Existing in the backlight illuminating system of multi-string LED lamp, to ensure the current balance of each string LED branches, usually
A linear regulator (LDO) is all connected in every string branch to adjust the electric current for flowing through LED.In this way, the electricity of each string LED branches
Stream can be independently precisely controlled, and the circuit control schemes of multi-string LED of the prior art at this as shown in Figure 1, show
Example in, power stage circuit be Boost boost converters, multi-string LED circuit then by two string LED parallel connections exemplified by, feedback control side
Case is the peak-current mode with slope compensation.Due in practical applications, each conduction voltage drop for going here and there LED light string body and impedance
It is not quite similar, therefore itself whole pressure drop of each string LED difference, the voltage in the input voltage such as Fig. 1 of so each road LDO
VX1With voltage VX2It is and unequal.In order to ensure that two string LED branches can work normally, feedback signal should select voltage VX1And electricity
Press VX2Middle voltage junior, i.e. if VX1＜ VX2, then voltage VX1As feedback signal.
This control mode there are the problem of be：According to voltage VX1Although to feed back two string LED can be made all to work normally,
To VX2For, the voltage difference at LDO both ends will certainly it is bigger than normal very much, this is bigger than normal by the loss for causing this string LDO, thereby reduces
The efficiency of whole system.
The content of the invention
In view of this, the present invention proposes the current balance control circuit and control method of a kind of LED multi-path lamp string, passes through
By the LED light string all the way of pressure drop maximum using linear regulation pattern, remaining each road uses pwm pattern, using PWM controlling parties
After formula, only have the conduction voltage drop of switching tube in switching tube service time, in the switching tube turn-off time, loss is reduced to zero, compared to
The prior art can improve system effectiveness, mitigate the caloric value of module.
The current balance control circuit of a kind of LED multi-path lamp string according to the invention, including power stage circuit, Multi-path electricity
Stream adjusts circuit and feedback control circuit, and the power stage circuit receives input power and supplied with being converted to suitable output voltage
The LED multi-path lamp string,
The multichannel current regulating circuit is corresponded with the LED multi-path lamp string, also, multichannel current regulation electricity
Road is connected between the LED multi-path lamp string and ground, and the multichannel current regulating circuit is used to adjust the LED multi-path lamp string
Electric current；
The feedback control circuit receives the input voltage signal of the multichannel current regulating circuit, and reckling is selected to make
For voltage feedback signal, the feedback control circuit controls the power according to the voltage feedback signal and reference voltage signal
The output voltage signal of grade circuit；
Wherein, the current regulating circuit corresponding all the way of the pressure drop maximum of the LED multi-path lamp string is linear regulation mould
Formula；The current regulating circuit corresponding to remaining each paths of LEDs lamp string in addition to the LED light string all the way of pressure drop maximum is PWM
Shaping modes.
Preferably, the reference voltage signal is provided by generating circuit from reference voltage, the generating circuit from reference voltage bag
The first comparison circuit, logic circuit, counter and D/A converting circuit are included,
The comparison circuit receives the LED light string electric current letter corresponding all the way of the pressure drop maximum of the LED multi-path lamp string
Number and the first predetermined current signal, to generate comparison signal；
The logic circuit receives the comparison signal, to generate increase and decrease control signal and keep signal；
The counter receives the increase and decrease control signal and keeps signal, and stores initial reference voltage signal, according to
The increase and decrease control signal and holding signal carry out calculating processing to the initial reference voltage signal, are believed with the first number of output
Number；
First digital signal is converted to analog signal by the D/A converting circuit, to obtain subsequent controlling cycle
Reference voltage signal.
Further, first comparison circuit includes first comparator and the second comparator,
The first input end of the first comparator receives the corresponding all the way of the pressure drop maximum of the LED multi-path lamp string
LED light string current signal, the second input terminal receive the second predetermined current signal, and output terminal exports the first comparison signal, wherein, institute
The second predetermined current signal is stated less than the first predetermined current signal；
The first input end of second comparator receives the corresponding all the way of the pressure drop maximum of the LED multi-path lamp string
LED light string current signal, the second input terminal receive the 3rd predetermined current signal, and output terminal exports the second comparison signal, wherein, institute
The 3rd predetermined current signal is stated more than the predetermined current signal.
Preferably, the second predetermined current signal is for 90% more than the first predetermined current signal and less than institute
State the first predetermined current signal；
The 3rd predetermined current signal is 110% less than the first predetermined current signal and is more than described first in advance
If current signal.
Further, the current regulating circuit using PWM shaping modes includes first switch pipe, average value sampling electricity
Road and pwm control circuit,
The first switch pipe is grounded after being connected in series with corresponding LED light all the way, and the average value sample circuit is adopted
Sample flows through the current signal of the first switch pipe, to obtain the average current signal for characterizing the paths of LEDs lamp string electric current；
The pwm control circuit receives the average current signal and the reference current letter of characterization LED light string expectation electric current
Number, to generate first switch control signal, the first switch control signal controls the on off state of the first switch pipe, with
So that the electric current of the paths of LEDs lamp string is consistent with expectation electric current, wherein, the reference current signal and the predetermined current signal
It is equal in magnitude.
Further, the feedback control circuit includes error compensation circuit, the second comparison circuit and logic circuit,
The error compensation circuit receives the voltage feedback signal and reference voltage signal, is obtained after error compensation is handled
Obtain error compensating signal；
Second comparison circuit receives the work(of the error compensating signal, slope compensation signal and the power stage circuit
Rate switching current signal, to generate comparison signal；
The logic circuit receives the comparison signal and clock signal, to generate described in the control of power switch control signal
The switch motion of power switch in power stage circuit.
A kind of current balance control method of LED multi-path lamp string according to the invention, including,
It receives input power and supplies the LED multi-path lamp string to be converted to suitable output voltage；
According to the pressure drop maximum of LED multi-path lamp string voltage feedback signal all the way and reference voltage signal adjusting control
The output voltage signal；
Wherein, the current regulation mode of the LED light string all the way of the pressure drop maximum in the LED multi-path lamp string is adjusted to be linear
Section pattern；The current regulation mode of remaining each paths of LEDs lamp string in addition to the LED light string all the way of pressure drop maximum is PWM tune
Section pattern.
Further, the step of reference voltage signal generates includes,
The LED light string current signal corresponding all the way and first for receiving the pressure drop maximum of the LED multi-path lamp string are preset
Current signal, to generate comparison signal；
The comparison signal is received, to generate increase and decrease control signal and keep signal；
It receives the increase and decrease control signal, keep signal and initial reference voltage signal, according to the increase and decrease control signal
Calculating processing is carried out to the initial reference voltage signal with holding signal, to export the first digital signal；
First digital signal is converted into analog signal, to obtain the reference voltage signal of subsequent controlling cycle.
Further, the step of comparison signal generates includes,
The LED light string current signal corresponding all the way and second for comparing the pressure drop maximum of the LED multi-path lamp string are preset
Current signal generates the first comparison signal, wherein, the second predetermined current signal is less than the predetermined current signal；
The LED light string current signal corresponding all the way and the 3rd for comparing the pressure drop maximum of the LED multi-path lamp string are preset
Current signal generates the second comparison signal, wherein, the 3rd predetermined current signal is less than the predetermined current signal.
Preferably, the second predetermined current signal is for 90% more than the first predetermined current signal and less than described
First predetermined current signal；
The 3rd predetermined current signal is 110% less than the first predetermined current signal and is more than described first in advance
If current signal.
It can be seen from the above, the current balance control circuit and control method of the LED multi-path lamp string of the present invention, by by pressure drop
Maximum LED light string all the way uses linear regulation pattern, remaining each road uses pwm pattern, after PWM control modes,
Only has the conduction voltage drop of switching tube in switching tube service time, loss is reduced to zero in the switching tube turn-off time, compared to existing
Technology can improve system effectiveness.In addition, the reference voltage signal of feedback control circuit is arranged to adjustable, in this way,
In the case of LED light string pressure drop difference, on the one hand it can be protected according to the size of actual conditions automatic adjusument reference voltage signal
The voltage of card linear regulating circuit working condition is minimum, while also may be such that the output voltage of power stage circuit to can guarantee LED
The minimum value of lamp string normal work, system effectiveness further improve；Finally, the output voltage of power stage circuit can make for optimal value
The current amplitude and the current amplitude of the LED light string of linear regulation pattern for obtaining the LED light string of pwm pattern approach, circuit
Uniformity is good, practicability enhancing.
Description of the drawings
Fig. 1 show the circuit structure diagram of multi-string LED of the prior art；
Fig. 2 show the circuit diagram of the current balance control circuit of LED multi-path lamp string according to the invention；
Fig. 3 show a kind of embodiment of generating circuit from reference voltage described in Fig. 2；
Fig. 4 show the working waveform figure of the generating circuit from reference voltage of Fig. 3；
Fig. 5 a show the efficiency isoboles of the LED multi-path lamp string of the prior art；
Fig. 5 b show the efficiency isoboles of LED multi-path lamp string according to the invention.
Specific embodiment
Several preferred embodiments of the present invention are described in detail below in conjunction with attached drawing, but the present invention is not restricted to
These embodiments.The present invention covers any replacement, modification, equivalent method and side made in the spirit and scope of the present invention
Case.In order to which the public is made to have thorough understanding to the present invention, it is described in detail in present invention below preferred embodiment specific thin
Section, and description without these details can also understand the present invention completely for a person skilled in the art.
The circuit diagram of the current balance control circuit of LED multi-path lamp string according to the invention is shown with reference to figure 2, in this reality
It applies in example, the LED multi-path lamp string is by taking two-way as an example, such as the LED light string 1 and LED light string 2 in Fig. 2.The current balance control
Circuit includes power stage circuit, and power stage circuit is by taking Boost booster type topological structures as an example here, the power stage circuit bag
It includes the inductance L1 being connected between input power Vin and output terminal and diode D1, be connected to inductance L1's and diode D1
Power switch pipe Q1 between points of common connection and ground.It is suitable to be converted to that the power stage circuit receives input power Vin
Output voltage Vo supplies the LED multi-path lamp string.
Further, the current balance control circuit further includes multichannel current regulating circuit and feedback control circuit, institute
It states multichannel current regulating circuit to correspond with the LED multi-path lamp string, also, the multichannel current regulation is electrically connected to institute
It states between LED multi-path lamp string and ground, the multichannel current regulating circuit is adjusting the electric current of the LED multi-path lamp string, such as Fig. 2
Shown, the input voltage signal of two-way current regulating circuit is respectively Vx1 and Vx2.Preferably, the pressure of the LED multi-path lamp string
The maximum current regulating circuit corresponding all the way of drop is linear regulation pattern；Except pressure drop maximum LED light string all the way it
Current regulating circuit corresponding to each paths of LEDs lamp string of remaining outer is PWM shaping modes, in the present embodiment, with LED light string
Exemplified by 1 pressure drop maximum, therefore, LED light string 1 is linear regulation pattern, and LED light string 2 is PWM shaping modes.The feedback control
Circuit processed receives the input voltage signal of the multichannel current regulating circuit, and selects reckling as voltage feedback signal, institute
State the output voltage that feedback control circuit controls the power stage circuit according to the voltage feedback signal and reference voltage signal
Signal；Wherein, the reference voltage signal is provided by generating circuit from reference voltage.
Specifically, with reference to figure 2, in embodiments of the present invention, the current regulating circuit of linear regulation pattern is adjusted to be linear
Save device LDO, such as linear regulator of the prior art being made of switching tube, sampling resistor and error amplifying circuit.PWM is adjusted
The current regulating circuit of pattern include first switch pipe Q1, average value sample circuit 201 and pwm control circuit 202, described first
Switching tube Q1 is grounded after being connected in series with LED light string 2, and the first switch pipe is flowed through in the sampling of average value sample circuit 201
The current signal of Q1, to obtain the average current signal I for characterizing the paths of LEDs lamp string electric currentFB；The pwm control circuit 202 receives
The average current signal IFBWith the reference current signal I of characterization LED light string expectation electric currentREF, to generate first switch control letter
Number, the first switch control signal controls the on off state of the first switch pipe Q1, so that the electric current of the paths of LEDs lamp string
It is consistent with expectation electric current.Wherein, the pwm control circuit can be circuit structure of the prior art, such as by comparator and RD
The circuit that trigger is formed.
Further, in the present embodiment, the feedback control circuit includes error compensation circuit, the second comparison circuit
And logic circuit, as shown in Fig. 2, shown error compensation circuit includes error amplifier gm and compensation circuit, error amplifier gm
Inverting input receiving voltage feedback signal VFB, normal phase input end receive reference voltage signal Vref, handled through error compensation
Error compensating signal Vcomp is obtained afterwards；Wherein, the voltage feedback signal is the input voltage of the multichannel current regulating circuit
The reckling of signal, as shown in Fig. 2, it can be by the minimum voltage selection circuit that is made of diode to input voltage signal
Vx1 and Vx2 make choice.
Supplement is needed exist for, when power stage circuit starts, since two string LED branch currents are all not reaching to setting
Value, therefore the switch (being switched in LDO controls in switch and PWM controls) in two-way is full-gear, at this moment input voltage is believed
Number Vx1 and Vx2 is zero.At this point, no matter choosing voltage Vx1 or Vx2, the duty cycle in power stage circuit can all be caused to increase
Add, output voltage Vo rises.With gradually rising for output voltage, LED light string entirety pressure drop is smaller first electric current all the way,
It is 2 one tunnel of LED light string in this example, therefore Vx2 voltages rise comparatively fast, will be greater than Vx1, can pass through minimum voltage at this time and select electricity
Road is using input voltage signal Vx1 as the voltage feedback signal of feedback control circuit.
Further, the second comparison circuit is the comparator A1 of three end interfaces, and the first normal phase input end received power level is electric
The power switch current signal on road, the second normal phase input end receive slope compensation signal, and inverting input receives the error and mends
Repay signal Vcomp, output terminal output comparison signal；The logic circuit includes rest-set flip-flop and driver, the rest-set flip-flop
Reset terminal receive the comparison signal, set end receives clock signal, and output terminal output power switch controlling signal is transferred to
Driver, the driver control the switch of the power switch in the power stage circuit to move according to power switch control signal
Make.
In the above-described embodiments, by the way that by the LED light string all the way of pressure drop maximum, using linear regulation pattern, remaining each road is adopted
With pwm pattern, in this way, only having switching tube in first switch pipe service time using the LED light string of PWM control modes
Conduction voltage drop, in the first switch pipe turn-off time, loss is reduced to zero, can improve system effectiveness compared with the prior art.
But the reference voltage signal in the above-described embodiments, provided by generating circuit from reference voltage is usually fixed, and
Meeting the voltage request under 1 pressure drop maximum case of LED light string, prior art reference voltage signal is generally provided by voltage source,
Like this, in some smaller occasions of LED light string pressure drop, linear regulator will be caused to bear larger pressure drop, while work(
The output voltage Vo of rate grade circuit also can be larger, and the loss of such whole system can be larger, as a result, in the present invention, to described
Reference voltage signal optimizes processing, so that system can realize the maximization of efficiency in all cases.
The specific implementation of the generating circuit from reference voltage is as shown in figure 3, the reference voltage signal includes first
Comparison circuit, logic circuit 301, counter 302 and D/A converting circuit 303, in the present embodiment, first comparison circuit
301 specifically include comparator CMP1 and comparator CMP2.The first input end of comparator CMP1 receives the LED multi-path lamp string
The LED light string current signal corresponding all the way of pressure drop maximum, the present embodiment are the electric current of LED light string 1, are denoted as ILDO1, second
Input terminal receives the second predetermined current signal Iset-, the first comparison signal V of output terminal outputA, wherein, second predetermined current
Signal Iset-Less than the first predetermined current signal Iset, the first predetermined current signal IsetWith reference current signal IREFSize
It is equal, specifically, the second predetermined current signal is 90% more than the first predetermined current signal and less than described the
One predetermined current signal；The first input end of comparator CMP2 receive the LED multi-path lamp string pressure drop it is maximum all the way pair
The LED light string current signal I answeredLDO1, the 3rd predetermined current signal I of the second input terminal receptionset+, output terminal output second compares
Signal VB, wherein, the 3rd predetermined current signal Iset+More than the first predetermined current signal Iset, specifically, described
Three predetermined current signals are 110% less than the first predetermined current signal and are more than the first predetermined current signal.
Skilled person will appreciate that the first above-mentioned comparison circuit 301 can be caused by the way of two comparators
Control mode is more accurate, and in occasion of less demanding, above-mentioned first comparator circuit can be single comparator, by straight
It connects and compares LED light string current signal and predetermined current signal to judge the size of current LED light string current signal, no longer draw herein
Figure description.
The logic circuit 301 receives the first comparison signal VAWith the second comparison signal VB, increase and decrease control letter to generate
Number Add/Sub and keep signal Hold.The counter 302 receives the increase and decrease control signal Add/Sub and keeps signal
Hold, and initial reference voltage signal Vref0 is stored, according to the increase and decrease control signal and signal is kept to the initial reference
Voltage signal carries out calculating processing, and to export the first digital signal, in the present embodiment, the counter 302 also receives clock
Signal CLK carries out plus-minus processing along the moment in the triggering of clock signal to the initial reference voltage signal.
In the present embodiment, the logic circuit 301 and 302 specific control principle of counter are：Work as VA=0 and VB=0
When, (0 is low level here, and 1 is high level) shows that power stage circuit works normally not yet or LED light string electric current is built not yet
It erects and, do not start Vref step change functions at this time；Work as VA=0 and VBWhen=1, it is an error condition, does not start Vref equally
Step change function；Work as VA=1 and VBWhen=0, show ILDO1Reach setting value, started Vref steppings at this time and reduce function, and
And Hold keeps function not enable；Work as VA=1 and VBWhen=1, show that LED light string 1 has lost linear working state, start at this time
Vref steppings increase function, and after a step is increased, enable Hold and keep function, Vref value is fixed up.
Afterwards, the first digital signal that counter exports is converted to analog signal by the D/A converting circuit 302, to obtain
Obtain the reference voltage signal Vref of subsequent controlling cycle.
The working waveform figure of generating circuit from reference voltage is shown with reference to figure 4, is started to work the moment in circuit, initial reference
Voltage Vref0 is set larger, so that linear regulator, when into working condition, the electric current of LED light string 1 can be adjusted normally
It saves to the first pre-set current value Iset, afterwards, after power stage circuit normal work, at the t1 moment, by initial reference voltage
Vref0 carries out stepping and reduces a step, and after reduction, can judge the electric current of LED light string 1 be adjusted to the first pre-set current value
Iset if can be with, continues stepping and reduces a step, until to the t2 moment, when the electric current for finding LED light string 1 cannot be adjusted
It saves to the first pre-set current value Iset, then retract a step, and as the reference voltage signal Vref_ of power stage circuit
opt.In this way, in the case of different pressure drops, Vref value can be adjusted to suitable reference voltage level, on the one hand so that line always
The pressure drop of property adjuster LDO excessive will not cause energy dissipation, and the output voltage of power stage circuit on the other hand can be caused to believe
Number Vo is also reduced to suitable value, this can cause current amplitude to reduce, circuit for the LED light string of pwm pattern
Uniformity it is good, practicability enhancing.
Finally, the efficiency isoboles of the LED multi-path lamp string of the prior art is shown with reference to figure 5a；Fig. 5 b are according to the present invention
LED multi-path lamp string efficiency isoboles.LED light string is equivalent to the series circuit of voltage source and resistance, in Fig. 5 a and 5b
First string is equivalent to voltage source V1 and resistance R1 is in series, and the second string is equivalent to voltage source V2 and resistance R2 is in series.
The power of lamp string is entered in terms of the output terminal of power stage circuit as Pin, when the electric current of two string LED branches reaches equal
During weighing apparatus, the electric current of two-way is equal, is I, then power is Pin=2VoI, then has：
To Fig. 5 a, efficiency is：
To Fig. 5 b, efficiency is：
As can be seen that compared with the prior art, the present invention can at least make system effectiveness promote Vx2/ from formula (2)
(2Vo).Assuming that actual circuit, 10 LED, electric current 100mA are often gone here and there, totally 2 string, Vx2=1.2V, Vo=30V are using the present invention
Technical solution, system effectiveness can will at least promote 2%.In this way, for having for the LED parallel systems more gone here and there, system
Efficiency will be promoted more.
Finally, the present invention proposes a kind of current balance control method of LED multi-path lamp string, including,
It receives input power and supplies the LED multi-path lamp string to be converted to suitable output voltage；
According to the pressure drop maximum of LED multi-path lamp string voltage feedback signal all the way and reference voltage signal adjusting control
The output voltage signal；
Wherein, the current regulation mode of the LED light string all the way of the pressure drop maximum in the LED multi-path lamp string is adjusted to be linear
Section pattern；The current regulation mode of remaining each paths of LEDs lamp string in addition to the LED light string all the way of pressure drop maximum is PWM tune
Section pattern.
Further, the step of reference voltage signal generates includes,
The LED light string current signal corresponding all the way and first for receiving the pressure drop maximum of the LED multi-path lamp string are preset
Current signal, to generate comparison signal；
The comparison signal is received, to generate increase and decrease control signal and keep signal；
It receives the increase and decrease control signal, keep signal and initial reference voltage signal, according to the increase and decrease control signal
Calculating processing is carried out to the initial reference voltage signal with holding signal, to export the first digital signal；
First digital signal is converted into analog signal, to obtain the reference voltage signal of subsequent controlling cycle.
The current balance control circuit and control method of the LED multi-path lamp string of the present invention, by the way that pressure drop is maximum all the way
LED light string uses linear regulation pattern, remaining each road uses pwm pattern, it is ensured that the lamp string of LED multi-path can be normal
Work, it is important that after PWM control modes, in pwm control circuit, only there is conducting to press in switching tube service time
Drop, is not lost in the switching tube turn-off time, can greatly improve system effectiveness compared with the prior art.In addition, feedback is controlled
The reference voltage signal of circuit processed optimizes, it on the one hand can be ensured linear according to actual conditions automatic adjusument
The voltage of adjusting circuit working state is minimum, while also may be such that the output voltage of power stage circuit to can guarantee LED light string just
The minimum value often to work, system effectiveness further improve；Finally, the output voltage of power stage circuit may be such that PWM for optimal value
The current amplitude of the LED light string of control model and the current amplitude of the LED light string of linear regulation pattern approach, the uniformity of circuit
It is good, practicability enhancing.
Above to the current balance control circuit and control method of the LED multi-path lamp string of preferred embodiment according to the invention
Detailed description is carried out, those of ordinary skill in the art can deduce other technologies or structure and circuit layout, member accordingly
Part etc. can be applied to the embodiment.
According to the embodiment of the present invention as described above, these embodiments are there is no all details of detailed descriptionthe, also not
It is only the specific embodiment to limit the invention.Obviously, as described above, can make many modifications and variations.This explanation
Book is chosen and specifically describes these embodiments, is in order to preferably explain the principle of the present invention and practical application, so that affiliated
Technical field technical staff can be used using modification of the invention and on the basis of the present invention well.The present invention is only by right
The limitation of claim and its four corner and equivalent.
Claims (10)
1. a kind of current balance control circuit of LED multi-path lamp string, including power stage circuit, multichannel current regulating circuit and feedback
Control circuit, the power stage circuit receive input power and supply the LED multi-path lamp string to be converted to suitable output voltage,
It is characterized in that,
The multichannel current regulating circuit is corresponded with the LED multi-path lamp string, also, the multichannel current regulating circuit connects
It is connected between the LED multi-path lamp string and ground, the multichannel current regulating circuit is used to adjust the electricity of the LED multi-path lamp string
Stream；
The feedback control circuit receives the input voltage signal of the multichannel current regulating circuit, and selects reckling as electricity
Feedback signal is pressed, the feedback control circuit controls the power stage electricity according to the voltage feedback signal and reference voltage signal
The output voltage signal on road；
Wherein, the reference voltage signal is according to the institute all the way of the pressure drop maximum of the first predetermined current signal and LED multi-path lamp string
Corresponding LED light string current signal setting, after power stage circuit normal work, the reference voltage signal is reduced
One step, and judge whether the value of the LED light string current signal corresponding all the way of the pressure drop maximum of LED multi-path lamp string can be with
The value of the first predetermined current signal is adjusted to, if can be with, continues that the reference voltage signal is made to reduce a step,
If cannot, the reference voltage signal is made to increase a step,
Wherein, the current regulating circuit corresponding all the way of the pressure drop maximum of the LED multi-path lamp string is linear regulation pattern；It removes
The current regulating circuit corresponding to remaining each paths of LEDs lamp string outside the LED light string all the way of the pressure drop maximum adjusts mould for PWM
Formula.
2. current balance control circuit according to claim 1, which is characterized in that the reference voltage signal is by with reference to electricity
Generation circuit is pressed to provide, the generating circuit from reference voltage includes the first comparison circuit, logic circuit, counter and digital-to-analogue conversion
Circuit,
First comparison circuit receives the LED light string electric current letter corresponding all the way of the pressure drop maximum of the LED multi-path lamp string
Number and the first predetermined current signal, to generate comparison signal；
The logic circuit receives the comparison signal, to generate increase and decrease control signal and keep signal；
The counter receives the increase and decrease control signal and keeps signal, and stores initial reference voltage signal, according to described
Increase and decrease control signal and signal is kept to carry out calculating processing to the initial reference voltage signal, to export the first digital signal；
First digital signal is converted to analog signal by the D/A converting circuit, to obtain the reference of subsequent controlling cycle
Voltage signal.
3. current balance control circuit according to claim 2, which is characterized in that first comparison circuit includes first
Comparator and the second comparator,
The first input end of the first comparator receives the LED corresponding all the way of the pressure drop maximum of the LED multi-path lamp string
Lamp string current signal, the second input terminal receive the second predetermined current signal, and output terminal exports the first comparison signal, wherein, it is described
Second predetermined current signal is less than the first predetermined current signal；
The first input end of second comparator receives the LED corresponding all the way of the pressure drop maximum of the LED multi-path lamp string
Lamp string current signal, the second input terminal receive the 3rd predetermined current signal, and output terminal exports the second comparison signal, wherein, it is described
3rd predetermined current signal is more than the first predetermined current signal.
4. current balance control circuit according to claim 3, which is characterized in that
The second predetermined current signal is 90% more than the first predetermined current signal and electricity is preset less than described first
Flow signal；
The 3rd predetermined current signal is 110% less than the first predetermined current signal and electricity is preset more than described first
Flow signal.
5. current balance control circuit according to claim 2, which is characterized in that the electricity using PWM shaping modes
Stream, which adjusts circuit, includes first switch pipe, average value sample circuit and pwm control circuit,
The first switch pipe is grounded after being connected in series with corresponding LED light all the way, the average value sampling circuit samples stream
The current signal of the first switch pipe is crossed, to obtain the average current signal for characterizing the paths of LEDs lamp string electric current；
The pwm control circuit receives the average current signal and the reference current signal of characterization LED light string expectation electric current, with
First switch control signal is generated, the first switch control signal controls the on off state of the first switch pipe, so that
The electric current of the paths of LEDs lamp string is consistent with expectation electric current, wherein, the reference current signal and the first predetermined current signal
It is equal in magnitude.
6. current balance control circuit according to claim 2, which is characterized in that the feedback control circuit includes error
Compensation circuit, the second comparison circuit and logic circuit,
The error compensation circuit receives the voltage feedback signal and reference voltage signal, is missed after error compensation is handled
Poor thermal compensation signal；
The power that second comparison circuit receives the error compensating signal, slope compensation signal and the power stage circuit is opened
Current signal is closed, to generate comparison signal；
The logic circuit receives the comparison signal and clock signal, and the power is controlled to generate power switch control signal
The switch motion of power switch in grade circuit.
7. a kind of current balance control method of LED multi-path lamp string, which is characterized in that including,
It receives input power and supplies the LED multi-path lamp string to be converted to suitable output voltage；According to the LED multi-path lamp string
Pressure drop maximum voltage feedback signal all the way and reference voltage signal adjusting control described in output voltage signal；Wherein, it is described
Reference voltage signal is according to the LED light string corresponding all the way of the pressure drop maximum of the first predetermined current signal and LED multi-path lamp string
Current signal is set, and after power stage circuit normal work, the reference voltage signal is reduced a step, and is judged more
Whether the value of the LED light string current signal corresponding all the way of the pressure drop maximum of paths of LEDs lamp string can be adjusted to described first
The value of predetermined current signal if can be with, continues that the reference voltage signal is made to reduce a step, if cannot, make institute
Stating reference voltage signal increases a step,
Wherein, the current regulation mode of the LED light string all the way of the pressure drop maximum in the LED multi-path lamp string is linear regulation mould
Formula；The current regulation mode of remaining each paths of LEDs lamp string in addition to the LED light string all the way of pressure drop maximum adjusts mould for PWM
Formula.
8. current balance control method according to claim 7, which is characterized in that the step that the reference voltage signal generates
Suddenly further comprise,
Receive the LED light string current signal corresponding all the way and the first predetermined current of the pressure drop maximum of the LED multi-path lamp string
Signal, to generate comparison signal；
The comparison signal is received, to generate increase and decrease control signal and keep signal；
It receives the increase and decrease control signal, keep signal and initial reference voltage signal, according to the increase and decrease control signal and guarantor
It holds signal and calculating processing is carried out to the initial reference voltage signal, to export the first digital signal；
First digital signal is converted into analog signal, to obtain the reference voltage signal of subsequent controlling cycle.
9. current balance control method according to claim 8, which is characterized in that the step of comparison signal generates into
One step includes,
Compare the LED light string current signal corresponding all the way and the second predetermined current of the pressure drop maximum of the LED multi-path lamp string
Signal generates the first comparison signal, wherein, the second predetermined current signal is less than the first predetermined current signal；
Compare the LED light string current signal corresponding all the way and the 3rd predetermined current of the pressure drop maximum of the LED multi-path lamp string
Signal generates the second comparison signal, wherein, the 3rd predetermined current signal is less than the first predetermined current signal.
10. current balance control method according to claim 9, which is characterized in that
The second predetermined current signal is 90% more than the first predetermined current signal and electricity is preset less than described first
Flow signal；
The 3rd predetermined current signal is 110% less than the first predetermined current signal and electricity is preset more than described first
Flow signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510192386.5A CN104822199B (en) | 2015-04-20 | 2015-04-20 | The current balance control circuit and control method of a kind of LED multi-path lamp string |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510192386.5A CN104822199B (en) | 2015-04-20 | 2015-04-20 | The current balance control circuit and control method of a kind of LED multi-path lamp string |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104822199A CN104822199A (en) | 2015-08-05 |
| CN104822199B true CN104822199B (en) | 2018-05-22 |
Family
ID=53732330
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510192386.5A Active CN104822199B (en) | 2015-04-20 | 2015-04-20 | The current balance control circuit and control method of a kind of LED multi-path lamp string |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104822199B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106855390B (en) * | 2016-11-15 | 2020-07-14 | 天津大学 | Self-adaptive light-emitting adjusting method for infrared L ED light source light pen measuring system |
| CN110798943B (en) * | 2019-12-03 | 2023-08-15 | 珠海格力电器股份有限公司 | Current control circuit, method and driving system for realizing phase interleaving |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005085969A1 (en) * | 2004-02-05 | 2005-09-15 | Monolithic Power Systems Inc. | A dc/dc voltage regulator with automatic current sensing selectability for linear and switch mode operation utilizing a single voltage reference |
| US8058810B2 (en) * | 2009-05-07 | 2011-11-15 | Linear Technology Corporation | Method and system for high efficiency, fast transient multi-channel LED driver |
| CN102548109B (en) * | 2010-12-30 | 2014-05-28 | 英飞特电子（杭州）股份有限公司 | Load driving device and system |
| TWI465151B (en) * | 2011-12-07 | 2014-12-11 | Richtek Technology Corp | Dimming controller and method for controlling a brightness of leds |
| US8988004B2 (en) * | 2013-01-18 | 2015-03-24 | Semiconductor Components Industries, Llc | Method of forming a current controller for an LED and structure therefor |
| CN103796398B (en) * | 2014-02-21 | 2016-01-06 | 南京矽力杰半导体技术有限公司 | A kind of drive circuit of multi-path parallel LEDs lamp string and driving method |
-
2015
- 2015-04-20 CN CN201510192386.5A patent/CN104822199B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN104822199A (en) | 2015-08-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103052203B (en) | LED (Light Emitting Diode) control circuit and control method thereof | |
| US7279869B2 (en) | PFM control circuit for DC regulator | |
| US9648677B2 (en) | LED driving circuit and method using single inductor | |
| CN106992681B (en) | Switch conversion circuit with multi-mode constant current control | |
| US8476888B1 (en) | Switching regulator providing current regulation based on using switching transistor current to control on time | |
| US9615415B2 (en) | LED driving circuit and method using single inductor | |
| CN104836427B (en) | Switching regulator control circuit and switching regulator | |
| US9841779B2 (en) | Variable reference signal generator used with switching mode power supply and the method thereof | |
| TWI363946B (en) | Power supplies, power supply controllers, and power supply controlling methods | |
| TW200425607A (en) | Multi-phase buck converter with programmable phase selection | |
| CN111819779B (en) | Power supply | |
| US10492259B2 (en) | Dimmable LED driver and dimming method | |
| CN110798939A (en) | LED driving circuit and method | |
| US20200076307A1 (en) | Frequency control circuit, control method and switching converter | |
| CN104822198B (en) | A kind of control circuit and control method of LED multi-path lamp string | |
| US11602020B2 (en) | Dimming signal generation circuit, dimming signal generation method and LED driver | |
| CN104822199B (en) | The current balance control circuit and control method of a kind of LED multi-path lamp string | |
| KR20130032844A (en) | Adaptive biasing for integrated circuits | |
| CN107079555B (en) | Linear post regulator | |
| CN112383220B (en) | Control circuit and switching converter using same | |
| CN109327141A (en) | A kind of wide-range voltage and High-current output method and power-supply system | |
| CN103516218B (en) | Power supply device | |
| US10638560B2 (en) | LED driver with a silicon controlled dimmer and control method thereof | |
| WO2023040566A1 (en) | Boost converter and driver circuit for driving high-side switching transistor thereof | |
| CN101394700B (en) | Constant current regulating circuit having current sensing loop |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| EXSB | Decision made by sipo to initiate substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 210023 Xu Zhuang Software Park, 699-27 Xuanwu Avenue, Xuanwu District, Jiangsu, Nanjing Province, Room 302, B District, F building, three District, China Patentee after: Nanjing Sili Microelectronics Technology Co., Ltd Address before: 210023 Xu Zhuang Software Park, 699-27 Xuanwu Avenue, Xuanwu District, Jiangsu, Nanjing Province, Room 302, B District, F building, three District, China Patentee before: Silergy Semiconductor Technology (Hangzhou) Ltd. |