CN113727487B - Driving method and driving circuit for multi-channel LED lamp string - Google Patents
Driving method and driving circuit for multi-channel LED lamp string Download PDFInfo
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- CN113727487B CN113727487B CN202011136959.XA CN202011136959A CN113727487B CN 113727487 B CN113727487 B CN 113727487B CN 202011136959 A CN202011136959 A CN 202011136959A CN 113727487 B CN113727487 B CN 113727487B
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- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
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Abstract
The invention discloses a driving method and a driving circuit of a multi-path LED lamp string, wherein a first reference value lower than expected current of the LED lamp string is set for each path of LED lamp string, a first operation signal is obtained by operation amplification according to the first reference value and error of a sampling voltage signal, and then the output voltage of a voltage regulator is regulated according to the minimum value in the multi-path first operation signal so as to ensure that each path of LED lamp string has sufficient working voltage; and the brightness of each LED lamp string is monitored in real time, when the brightness control detection signal of a certain LED lamp string is detected to reach the brightness control reference signal of the expected brightness output of the LED lamp string of the branch, the first operation signal of the branch is closed to regulate the output voltage of the voltage regulator and the current of the LED lamp string of the branch is closed, so that the voltage requirements of all the LED lamp strings are met, the voltage drop of the linear regulator is reduced, and the system power consumption is reduced.
Description
Technical Field
The invention relates to the technical field of LED driving, in particular to a driving method and a driving circuit of a multi-path LED lamp string.
Background
In the LED lighting technology applied to the backlight source, a plurality of LED strings are often arranged in parallel for use, a driving controller provides sufficient operating voltage to the plurality of LED strings through a voltage regulator, and current of the LED strings is regulated through a linear regulator (such as LDO) connected in series with the LED strings.
As shown in fig. 1, in the prior art, one path of LED lamp string with the largest voltage drop in the multiple paths of LED lamp strings is obtained through a minimum voltage feedback circuit, and the output voltage of the voltage regulator is regulated through a feedback loop, so that the voltage drop requirement of the one path of LED lamp string with the largest voltage drop is met.
The problem with the control method is that the voltage drop of each string of LEDs is different due to the manufacturing difference, and the voltage drop of each string of LEDs in other ways is smaller than that of the largest LED string, so that the voltage drop on the corresponding linear regulator LDO in other ways is larger, the power loss on the LDO is increased, and the system efficiency is lower.
Disclosure of Invention
Therefore, the present invention is directed to a driving method and a driving circuit for a multi-path LED light string, which are used for solving the technical problems of the prior art that the voltage drop of the linear regulator is large and the power consumption is large.
The technical solution of the present invention is to provide a driving method of a multi-path LED string light, wherein the multi-path LED string light is powered by a voltage regulator, and the method comprises the following steps:
s1: setting a first reference value lower than the expected current of each LED lamp string, sampling to obtain a sampling voltage signal representing the current of the LED lamp string, and carrying out operation comparison on the sampling voltage signal and the first reference value to obtain a first operation signal;
selecting the minimum value in the multiple paths of first operation signals by using a level selection circuit, and adjusting the output voltage of the voltage regulator according to the minimum value;
s2: setting a second reference value higher than the expected current of each LED lamp string, and controlling and adjusting the working current of the LED lamp string according to the second reference value;
s3: monitoring the brightness of each path of LED lamp string, obtaining a brightness control detection signal, and comparing the brightness control detection signal with a brightness control reference signal representing the expected brightness output of the path of LED lamp string;
when the brightness control detection signal obtained by comparison reaches the brightness control reference signal representing the expected brightness output of the LED lamp string, the transmission of the first operation signal to the level selection circuit is cut off, and the adjustment of the working current of the LED lamp string is closed.
Preferably, in step S1, the first reference value V REF1 The method specifically comprises the following steps:
V REF1 =I LED ×R SN （1-B%）
wherein I is LED R is the expected current of the LED light string SN And B is a natural number, and the setting range of B is larger than zero and smaller than a preset value, wherein the preset value is that the brightness of the corresponding LED lamp string is equal to the expected brightness of the LED lamp string when the current of the LED lamp string is at the maximum switching duty ratio.
Preferably, in step S3, the step of acquiring the brightness control detection signal includes:
obtaining a sampling voltage signal representing the current of the LED lamp string through sampling;
and integrating the sampling voltage signal in real time to obtain the brightness control detection signal.
Preferably, the specific step of selecting the minimum value among the multiple paths of the first operation signals in step S1 includes: the multi-path LED lamp string respectively carries out operational amplification on errors of the sampling voltage signal and the first reference value so as to obtain multi-path first operation signals;
and the multiple paths of first operation signals are subjected to minimum value selection through the level selection circuit so as to obtain the minimum value in the multiple paths of first operation signals.
Preferably, in step S3, the step of cutting off the transmission of the first operation signal to the level selection circuit specifically includes,
a switching tube is connected between an output transmission end of the first operation signal and the level selection circuit, and when the brightness control detection signal obtained by comparison reaches the brightness control reference signal representing the expected brightness output of the LED lamp string, the switching tube is turned off; or alternatively, the method can be used for processing,
when the brightness control detection signal obtained by comparison reaches the brightness control reference signal representing the expected brightness output of the LED lamp string, an enabling signal is generated to prohibit the operation comparison process of the sampling voltage signal and the first reference value.
Preferably, in step S2, the second reference value V REF2 The method specifically comprises the following steps:
V REF2 =I LED ×R SN （1+A%）
wherein I is LED R is the expected current of the LED light string SN For sampling resistance, A is a natural number, the setting range is greater than zero and I is made LED (1+A%) is less than the maximum bearing current of LED lamp string.
Preferably, in step S3, the step of turning off the adjustment of the working current of the LED string specifically includes turning off the main switching tube for adjusting the working current of the LED string when the comparison obtains the brightness control detection signal to reach the reference signal indicating the desired luminous flux of the LED string.
According to the driving circuit of the multi-path LED lamp string, the multi-path LED lamp string is powered by the voltage regulator, the driving circuit comprises a path of voltage feedback circuit, a path of current regulating circuit and a path of brightness control circuit corresponding to each path of LED lamp string, and the driving circuit also comprises a level selecting circuit,
the voltage feedback circuit receives a first reference value lower than the expected current of a corresponding LED lamp string, samples and obtains a sampling voltage signal representing the current of the LED lamp string, and compares the sampling voltage signal with the first reference value in an operation manner to obtain a first operation signal;
the current regulating circuit receives a second reference value higher than the expected current of a corresponding LED lamp string, and controls and regulates the working current of the LED lamp string according to the second reference value;
the brightness control circuit monitors the brightness of the corresponding LED lamp string, obtains a brightness control detection signal, and compares the brightness control detection signal with a brightness control reference signal representing expected brightness output of the LED lamp string to obtain a comparison signal;
the voltage feedback circuit outputs a plurality of first operation signals, the level selection circuit selects the minimum value in the plurality of first operation signals, and the output voltage of the voltage regulator is regulated according to the minimum value;
when the brightness control circuit compares to obtain that the brightness control detection signal of a certain path reaches the brightness control reference signal, the driving circuit cuts off the transmission of the first operation signal of the path to the level selection circuit, and closes the adjustment of the working current of the LED lamp string of the path.
Preferably, the driving circuit is characterized in that each path of the voltage feedback circuit comprises a sampling resistor and an operational amplifying circuit which are connected in series with the path of LED lamp string,
an input terminal of the operational amplifier circuit is connected to the sampling resistor non-ground terminal to obtain the sampling voltage signal,
the operational amplifier circuit performs operational comparison on the sampling voltage signal and the first reference value to obtain the first operational signal.
Preferably, the driving circuit further comprises a first switch corresponding to each path of LED light string,
the first switch is connected between the output end of the operational amplifier circuit and the level selection circuit,
the first switch controls the switch state by the comparison signal output by the corresponding path of light brightness control circuit.
Preferably, the level selection circuit comprises a plurality of diodes, the diodes are in one-to-one correspondence with the multi-path LED light strings,
the cathode of each diode is connected to one power terminal of the first switch, and the anodes of the plurality of diodes are connected to the voltage regulator.
Preferably, each path of the light brightness control circuit comprises an integrating circuit and a comparing circuit,
the integrating circuit obtains a sampling voltage signal through the sampling resistor, integrates the sampling voltage signal with time in real time to obtain the brightness control detection signal,
the comparison circuit compares the brightness control detection signal with a brightness control reference signal representing expected brightness output of the LED lamp string, and generates the comparison signal.
Preferably, each path of the current regulating circuit comprises a main switching tube and a sampling resistor which are connected in series with the path of LED lamp string, and a current regulating control circuit for controlling the main switching tube,
the current regulation control circuit obtains a sampling voltage signal through the sampling resistor, and compares the sampling voltage signal with the second reference value in an operation manner so as to transmit a second operation result to the control end of the main switching tube,
when the comparison signal represents that the brightness control detection signal reaches a brightness control reference signal representing the expected brightness output of the LED lamp string, the current regulating circuit cuts off the transmission of the second operation result to the control end of the main switching tube through a switching tube.
Preferably, the first ginsengTest value V REF1 The method specifically comprises the following steps:
V REF1 =I LED ×R SN （1-B%）
wherein I is LED R is the expected current of the LED light string SN Setting the range of B to be larger than zero and smaller than a preset value for the resistance value of the sampling resistor, wherein the preset value is that the brightness of the corresponding LED lamp string is equal to the expected brightness of the LED lamp string when the current of the LED lamp string is at the maximum switching duty ratio, and/or,
the second reference value V REF2 The method specifically comprises the following steps:
V REF2 =I LED ×R SN （1+A%）
wherein I is LED R is the expected current of the LED lamp string of the corresponding branch SN For the resistance value of the sampling resistor, A is a natural number, and the setting range of A is larger than zero and is made to be I LED (1+A%) is less than the maximum bearing current of LED lamp string.
By adopting the driving method and the driving circuit of the multi-path LED lamp string, the first operation signal is obtained by setting the first reference value lower than the expected current of the LED lamp string for each path of LED lamp string according to the operation comparison of the first reference value and the sampling voltage signal, then the output voltage of the voltage regulator is regulated according to the minimum value in the multi-path first operation signal so as to ensure the sufficient working voltage of each path of LED lamp string, the brightness of each path of LED lamp string is monitored in real time, and when the brightness control detection signal of a certain path is detected to reach the brightness control reference signal of the expected brightness output of the path of LED lamp string, the first operation signal of the path is closed to regulate the output voltage of the voltage regulator and close the current regulation of the path of LED lamp string, so that the output voltage of the voltage regulator can not generate excessive margin, the voltage drop of the linear regulator is reduced, and the system power consumption is reduced.
Drawings
FIG. 1 is a circuit control block diagram of a prior art multi-channel LED light string;
FIG. 2 is a circuit block diagram of a driving circuit of a multi-channel LED string light according to the present invention;
FIG. 3 is a circuit diagram of an embodiment of a driving circuit for a multi-channel LED string according to the present invention;
FIG. 4 is a circuit diagram of an embodiment of the current regulation circuit of FIG. 3;
FIG. 5 is a flow chart of a driving circuit of a multi-channel LED string light according to the present invention
Description of the embodiments
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to these embodiments only. The invention is intended to cover any alternatives, modifications, equivalents, and variations that fall within the spirit and scope of the invention.
In the following description of preferred embodiments of the invention, specific details are set forth in order to provide a thorough understanding of the invention, and the invention will be fully understood to those skilled in the art without such details.
The invention is more particularly described by way of example in the following paragraphs with reference to the drawings. It should be noted that the drawings are in a simplified form and are not to scale precisely, but rather are merely intended to facilitate and clearly illustrate the embodiments of the present invention.
Referring to fig. 2-4, fig. 2 is a circuit block diagram of a driving circuit of a multi-path LED string according to the present invention, fig. 3 is a specific circuit diagram of an embodiment of a driving circuit of a multi-path LED string according to the present invention, and fig. 4 is a circuit diagram of an embodiment of a current adjusting circuit of fig. 3.
Referring to fig. 2, in the driving circuit of the multi-path LED lamp string according to the embodiment of the present invention, the multi-path LED lamp string is powered by a voltage regulator, the voltage regulator receives an input voltage Vin to generate a dc output voltage Vo to supply the multi-path LED lamp string, the multi-path LED lamp string includes LED lamp strings 1 to n connected in parallel, and the voltage regulator may be a voltage converter with a voltage boosting type, a voltage dropping type, a voltage boosting type, a flyback type, a forward type, etc.
The driving circuit comprises a voltage feedback circuit, a current regulating circuit and a brightness control circuit corresponding to each LED lamp string, and the driving circuit also comprises level selectionThe voltage feedback circuit receives a first reference value V lower than the expected current of a corresponding path of LED lamp string REF11 (the same applies hereinafter) and samples to obtain a sampled voltage signal V representing the current of the first LED string SN1 Performing operation comparison on the sampling voltage signal and the first reference value to obtain a first operation signal V1; the current regulating circuit receives a second reference value V higher than the expected current of the corresponding one path of LED lamp string REF21 And controlling and adjusting the working current of the LED lamp string according to the second reference value; the brightness control circuit monitors the brightness of the corresponding LED lamp string and obtains a brightness control detection signal V BI1 The brightness control detection signal V BI1 And a brightness control reference signal V representing the expected brightness output of the LED lamp string RBI1 Comparing to obtain a comparison signal V B1 The method comprises the steps of carrying out a first treatment on the surface of the The voltage feedback circuit outputs a plurality of first operation signals (V1 to Vn), the level selection circuit selects the minimum value of the plurality of first operation signals, and the output voltage Vo of the voltage regulator is regulated according to the minimum value; when the brightness control circuit compares to obtain that the brightness control detection signal of a certain path reaches the brightness control reference signal, the driving circuit cuts off the transmission of the first operation signal of the path to the level selection circuit, and closes the adjustment of the working current of the LED lamp string of the path.
Here, the first reference value V REF1 The method specifically comprises the following steps:
V REF1 =I LED ×R SN （1-B%）
wherein I is LED R is the expected current of the LED light string SN And B is a natural number, the setting range of B is larger than zero and smaller than a preset value, the preset value is that the brightness of the corresponding LED lamp string is equal to the expected brightness of the LED lamp string when the current of the LED lamp string is in the maximum switching duty ratio, and the maximum switching duty ratio is that the switch for adjusting the current of the LED lamp string is in the 100% duty ratio.
Here, the second reference value V REF2 Specifically arranged squareThe method comprises the following steps:
V REF2 =I LED ×R SN （1+A%）
wherein I is LED R is the expected current of the LED lamp string of the corresponding branch SN For the resistance value of the sampling resistor, A is a natural number, and the setting range of A is larger than zero and is made to be I LED (1+A%) is less than the maximum bearing current of LED lamp string. It should be noted that, the values a and B herein are values that can be taken by the user according to practical situations.
According to the control scheme, the condition that the driving voltage of one LED lamp string is insufficient can be monitored, the output voltage is timely adjusted to meet the working voltage of the LED lamp string, the output voltage of the voltage regulator has no redundant margin, the circuit power consumption is low, the brightness output of each LED lamp string can be controlled, and the brightness output of each LED lamp string is ensured to be matched with the required brightness.
Specifically, referring to fig. 3, in this embodiment, each of the voltage feedback circuits includes a sampling resistor R1 connected in series with the LED string, and an operational amplifier circuit (e.g., an operational amplifier) having one input terminal connected to the non-ground terminal of the sampling resistor to obtain the sampled voltage signal V SN1 The operational amplifier circuit outputs the sampling voltage signal V SN1 With the first reference value V REF11 And performing operation comparison to obtain the first operation signal V1.
Each path of the brightness control circuit comprises an integrating circuit and a comparison circuit, wherein the integrating circuit obtains a sampling voltage signal V through the sampling resistor SN1 (here, the sampling resistor R1 may be shared) and integrates the sampling voltage signal over time in real time to obtain the brightness control detection signal V BI1 ，
The comparison circuit compares the brightness control detection signal V BI1 And a brightness control reference signal V representing the expected brightness output of the LED lamp string RBI1 And generates the comparison signal V B1 。
It should be explained here that the brightness control detection signal is multiplied by a certain currentThe brightness of the LED lamp string is represented on the LED lamp string by the consumed time to obtain the corresponding product area, namely, different detection signals correspond to different brightness outputs, so that the brightness of the LED lamp string can be monitored in real time through the size of the detection signals. Brightness control reference signal V representing expected brightness output of the LED lamp string RBI1 The multiple brightness control reference signals may be the same or different, as provided by an external circuit or controller, depending on the application.
In this embodiment, the driving circuit further includes a first switch M1 corresponding to each LED string, where the first switch is connected between the output end of the operational amplifier circuit and the level selection circuit, and the first switch is controlled by a comparison signal VB1 output by the brightness control circuit corresponding to one path to control the switching state of the first switch.
In one embodiment, the level selection circuit includes a plurality of diodes, the plurality of diodes being in one-to-one correspondence with the multi-path LED light string, a cathode of each of the diodes being connected to one power terminal of the first switch, anodes of the plurality of diodes being connected to the voltage regulator, where anodes of the plurality of diodes may be connected to a control circuit of the voltage regulator, such as to a connection point of a voltage regulator output voltage feedback signal. When a certain path of power supply voltage is insufficient, the corresponding first operation signal is reduced, and the corresponding diode of the path of power supply voltage is conducted, so that the output voltage feedback signal is pulled down, and therefore, the output voltage is regulated up, and the power supply requirement of the path of LED lamp string is met. Those skilled in the art will appreciate that the level selection circuit may also be constructed for other suitable devices.
Further, referring to fig. 3, in an embodiment of the present invention, each of the current adjusting circuits includes a main switching tube Q1 and a sampling resistor (which may be shared by the sampling resistor R1) connected in series with the LED string, and a current adjusting control circuit 1 for controlling the main switching tube, referring to fig. 4, the current adjusting control circuit 1 includes an operational amplifier OP, and the current adjusting control circuit obtains a sampling voltage signal V through the sampling resistor SN Calculation ofThe amplifier OP samples the voltage signal V SN And the second reference value V REF21 And performing operation comparison to transmit a second operation result to the control end of the main switching tube Q1.
Each circuit of the current regulating circuit further comprises a first switching tube S1 and a pull-down circuit, wherein the first switching tube S1 is connected between the output end of the operational amplifier OP and the control end of the main switching tube Q, and when the comparison signal V B1 When the brightness control detection signal reaches a brightness control reference signal representing the expected brightness output of the LED lamp string, the comparison signal becomes invalid at a low level, the first switching tube S1 is disconnected, and the pull-down circuit pulls down the control terminal voltage of the main switching tube. Here, the pull-down circuit may be configured of a switching tube and a pull-down current source, but is not limited thereto, the pull-down circuit receives a comparison signal, when the comparison signal changes to a high-level active state, the switching tube is turned on to enable the pull-down current source to pull down the voltage of the control end of the main switching tube, and the main switching tube is turned off, so that the adjustment of the current of the LED string is turned off.
According to the driving circuit provided by the embodiment of the invention, on one hand, the output voltage of the voltage regulator is regulated to meet the power supply voltage requirement of the LED lamp string through the feedback of the minimum value of the multipath first operation signals, and no excessive margin exists, so that the voltage drop of the main power tube is not too high, the system power consumption is reduced, and on the other hand, the brightness of the LED lamp string of each path is matched with the required brightness requirement through the accurate control of the brightness of light, the conduction time of the main power tube is reduced, and the system efficiency is further improved.
In a second aspect, referring to fig. 5, the present invention further discloses a driving method of a multi-path LED string, where the multi-path LED string is powered by a voltage regulator, and the method includes the following steps:
s1: setting a first reference value lower than the expected current of each LED lamp string, sampling to obtain a sampling voltage signal representing the current of the LED lamp string, and carrying out operation comparison on the sampling voltage signal and the first reference value to obtain a first operation signal;
selecting the minimum value in the multiple paths of first operation signals by using a level selection circuit, and adjusting the output voltage of the voltage regulator according to the minimum value;
s2: setting a second reference value higher than the expected current of each LED lamp string, and controlling and adjusting the working current of the LED lamp string according to the second reference value;
s3: monitoring the brightness of each path of LED lamp string, obtaining a brightness control detection signal, and comparing the brightness control detection signal with a brightness control reference signal representing the expected brightness output of the path of LED lamp string;
when the brightness control detection signal obtained by comparison reaches the brightness control reference signal representing the expected brightness output of the LED lamp string, the transmission of the first operation signal to the level selection circuit is cut off, and the adjustment of the working current of the LED lamp string is closed.
Preferably, in step S1, the first reference value V REF1 The method specifically comprises the following steps:
V REF1 =I LED ×R SN （1-B%）
wherein I is LED R is the expected current of the LED light string SN And B is a natural number, and the setting range of B is larger than zero and smaller than a preset value, wherein the preset value is that the brightness of the corresponding LED lamp string is equal to the expected brightness of the LED lamp string when the current of the LED lamp string is at the maximum switching duty ratio.
Preferably, in step S3, the step of acquiring the brightness control detection signal includes:
obtaining a sampling voltage signal representing the current of the LED lamp string through sampling;
and integrating the sampling voltage signal in real time to obtain the brightness control detection signal.
Preferably, in step S1, a plurality is selected
The specific steps of the minimum value in the first operation signal include:
the multi-path LED lamp string respectively carries out operational amplification on errors of the sampling voltage signal and the first reference value so as to obtain multi-path first operation signals;
the multiple paths of the first operation signals are subjected to minimum value selection by the level selection circuit so as to obtain
And multiplexing the minimum value in the first operation signals.
Preferably, in step S3, the step of cutting off the transmission of the first operation signal to the level selection circuit specifically includes,
a switching tube is connected between an output transmission end of the first operation signal and the level selection circuit, and when the brightness control detection signal obtained by comparison reaches the brightness control reference signal representing the expected brightness output of the LED lamp string, the switching tube is turned off; or alternatively, the method can be used for processing,
when the brightness control detection signal obtained by comparison reaches the brightness control reference signal representing the expected brightness output of the LED lamp string, an enabling signal is generated to prohibit the operation comparison process of the sampling voltage signal and the first reference value.
Preferably, in step S2, the second reference value V REF2 The method specifically comprises the following steps:
V REF2 =I LED ×R SN （1+A%）
wherein I is LED R is the expected current of the LED light string SN For sampling resistance, A is a natural number, the setting range is greater than zero and I is made LED (1+A%) is less than the maximum bearing current of LED lamp string.
Preferably, in step S3, the step of turning off the adjustment of the operating current of the LED string light specifically includes,
and when the brightness control detection signal obtained by comparison reaches the reference signal representing the expected luminous flux of the LED lamp string, switching off a main switching tube for regulating the working current of the LED lamp string.
The driving method of the embodiment of the invention can ensure that the voltage drop of the main power tube is not too high, reduce the power consumption of the system, accurately control the brightness of the LED lamp string and improve the system efficiency.
The above-described embodiments do not limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the above embodiments should be included in the scope of the present invention.
Claims (14)
1. The driving method of the multi-path LED lamp string is characterized by comprising the following steps of:
s1: setting a first reference value lower than the expected current of each LED lamp string, sampling to obtain a sampling voltage signal representing the current of the LED lamp string, and carrying out operation comparison on the sampling voltage signal and the first reference value to obtain a first operation signal;
selecting the minimum value in the multiple paths of first operation signals by using a level selection circuit, and adjusting the output voltage of the voltage regulator according to the minimum value;
s2: setting a second reference value higher than the expected current of each LED lamp string, and controlling and adjusting the working current of the LED lamp string according to the second reference value;
s3: monitoring the brightness of each path of LED lamp string, obtaining a brightness control detection signal, and comparing the brightness control detection signal with a brightness control reference signal representing the expected brightness output of the path of LED lamp string;
when the brightness control detection signal obtained by comparison reaches the brightness control reference signal representing the expected brightness output of the LED lamp string, the transmission of the first operation signal to the level selection circuit is cut off, and the adjustment of the working current of the LED lamp string is closed.
2. The driving method according to claim 1, wherein in step S1, the first reference value V REF1 The method specifically comprises the following steps:
V REF1 =I LED× R SN （1-B%）
wherein I is LED R is the expected current of the LED light string SN And B is a natural number, and the setting range of B is larger than zero and smaller than a preset value, wherein the preset value is that the brightness of the corresponding LED lamp string is equal to the expected brightness of the LED lamp string when the current of the LED lamp string is at the maximum switching duty ratio.
3. The driving method according to claim 1, wherein in step S3, the luminance control detection signal acquisition step includes:
obtaining a sampling voltage signal representing the current of the LED lamp string through sampling;
and integrating the sampling voltage signal in real time to obtain the brightness control detection signal.
4. The driving method according to claim 1, wherein a plurality of is selected in step S1
The specific steps of the minimum value in the first operation signal include:
the multi-path LED lamp string respectively carries out operational amplification on errors of the sampling voltage signal and the first reference value so as to obtain multi-path first operation signals;
the multiple paths of the first operation signals are subjected to minimum value selection by the level selection circuit so as to obtain
And multiplexing the minimum value in the first operation signals.
5. The driving method according to claim 1, wherein in step S3, the step of cutting off the transmission of the first operation signal to the level selection circuit comprises,
a switching tube is connected between an output transmission end of the first operation signal and the level selection circuit, and when the brightness control detection signal obtained by comparison reaches the brightness control reference signal representing the expected brightness output of the LED lamp string, the switching tube is turned off; or alternatively, the method can be used for processing,
when the brightness control detection signal obtained by comparison reaches the brightness control reference signal representing the expected brightness output of the LED lamp string, an enabling signal is generated to prohibit the operation comparison process of the sampling voltage signal and the first reference value.
6. The driving method according to claim 1, wherein in step S2, the second reference value V REF2 The method specifically comprises the following steps:
V REF2 =I LED× R SN （1+A%）
wherein I is LED R is the expected current of the LED light string SN For sampling resistance, A is a natural number, the setting range is greater than zero and I is made LED (1+A%) is less than the maximum bearing current of LED lamp string.
7. The driving method according to claim 1, wherein in step S3, the step of turning off the adjustment of the operation current of the LED string light comprises,
and when the brightness control detection signal obtained by comparison reaches the reference signal representing the expected luminous flux of the LED lamp string, switching off a main switching tube for regulating the working current of the LED lamp string.
8. A driving circuit of a plurality of LED lamp strings, the LED lamp strings are powered by a voltage regulator, the driving circuit is characterized by comprising a voltage feedback circuit, a current regulating circuit and a brightness control circuit corresponding to each LED lamp string, and the driving circuit also comprises a level selecting circuit,
the voltage feedback circuit receives a first reference value lower than the expected current of a corresponding LED lamp string, samples and obtains a sampling voltage signal representing the current of the LED lamp string, and compares the sampling voltage signal with the first reference value in an operation manner to obtain a first operation signal;
the current regulating circuit receives a second reference value higher than the expected current of a corresponding LED lamp string, and controls and regulates the working current of the LED lamp string according to the second reference value;
the brightness control circuit monitors the brightness of the corresponding LED lamp string, obtains a brightness control detection signal, and compares the brightness control detection signal with a brightness control reference signal representing expected brightness output of the LED lamp string to obtain a comparison signal;
the voltage feedback circuit outputs a plurality of first operation signals, the level selection circuit selects the minimum value in the plurality of first operation signals, and the output voltage of the voltage regulator is regulated according to the minimum value;
when the brightness control circuit compares to obtain that the brightness control detection signal of a certain path reaches the brightness control reference signal, the driving circuit cuts off the transmission of the first operation signal of the path to the level selection circuit, and closes the adjustment of the working current of the LED lamp string of the path.
9. The driving circuit as recited in claim 8 wherein each of said voltage feedback circuits comprises a sampling resistor in series with the LED string and an operational amplifier circuit,
an input terminal of the operational amplifier circuit is connected to the sampling resistor non-ground terminal to obtain the sampling voltage signal,
the operational amplifier circuit performs operational comparison on the sampling voltage signal and the first reference value to obtain the first operational signal.
10. The driving circuit of claim 9, wherein the driving circuit further comprises a first switch corresponding to each of the LED strings,
the first switch is connected between the output end of the operational amplifier circuit and the level selection circuit,
the first switch controls the switch state by the comparison signal output by the corresponding path of light brightness control circuit.
11. The driving circuit as recited in claim 10 wherein said level selection circuit comprises a plurality of diodes, said plurality of diodes being in one-to-one correspondence with said plurality of LED strings,
the cathode of each diode is connected to one power terminal of the first switch, and the anodes of the plurality of diodes are connected to the voltage regulator.
12. The driving circuit according to claim 8, wherein each of the light brightness control circuits comprises an integrating circuit and a comparing circuit,
the integrating circuit obtains a sampling voltage signal through a sampling resistor, integrates the sampling voltage signal in real time to obtain the brightness control detection signal,
the comparison circuit compares the brightness control detection signal with a brightness control reference signal representing expected brightness output of the LED lamp string, and generates the comparison signal.
13. The driving circuit according to claim 8, wherein each of the current adjusting circuits comprises a main switching tube and a sampling resistor connected in series with the LED string, and a current adjusting control circuit for controlling the main switching tube,
the current regulation control circuit obtains a sampling voltage signal through the sampling resistor, and compares the sampling voltage signal with the second reference value in an operation manner so as to transmit a second operation result to the control end of the main switching tube,
when the comparison signal represents that the brightness control detection signal reaches a brightness control reference signal representing the expected brightness output of the LED lamp string, the current regulating circuit cuts off the transmission of the second operation result to the control end of the main switching tube through a switching tube.
14. The drive circuit according to claim 8, wherein the first reference value V REF1 The method specifically comprises the following steps:
V REF1 =I LED× R SN （1-B%）
wherein I is LED Period for LED lamp stringObserving current, R SN Setting the range of B to be larger than zero and smaller than a preset value for the resistance value of the sampling resistor, wherein the preset value is that the brightness of the corresponding LED lamp string is equal to the expected brightness of the LED lamp string when the current of the LED lamp string is at the maximum switching duty ratio, and/or,
the second reference value V REF2 The method specifically comprises the following steps:
V REF2 =I LED× R SN （1+A%）
wherein I is LED R is the expected current of the LED lamp string of the corresponding branch SN For the resistance value of the sampling resistor, A is a natural number, and the setting range of A is larger than zero and is made to be I LED (1+A%) is less than the maximum bearing current of LED lamp string.
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| CN114466477B (en) * | 2021-12-31 | 2024-08-06 | 珠海雷特科技股份有限公司 | Constant current dimming method for multichannel light source, computer device and computer readable storage medium |
| CN114639339B (en) * | 2022-01-27 | 2023-09-26 | 南京中感微电子有限公司 | LED display system and multi-path LED driving circuit thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104185350A (en) * | 2014-09-12 | 2014-12-03 | 南京矽力杰半导体技术有限公司 | Multi-way LED constant current driving circuit and control method thereof |
| CN104822198A (en) * | 2015-04-20 | 2015-08-05 | 南京矽力杰半导体技术有限公司 | Control circuit and control method for multiple paths of LED lamp strings |
| CN110881231A (en) * | 2019-11-27 | 2020-03-13 | 成都芯源系统有限公司 | Dimming circuit and control method thereof |
| CN210491278U (en) * | 2019-07-19 | 2020-05-08 | 骆武宁 | Color and light adjusting device for parallel operation of multiple LED high-power driving modules |
| CN210579359U (en) * | 2019-08-30 | 2020-05-19 | 深圳爱克莱特科技股份有限公司 | LED lamp and driving circuit thereof |
| CN111613185A (en) * | 2019-02-26 | 2020-09-01 | 罗姆股份有限公司 | Light emitting element driving device, light emitting element driving system, and light emitting system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ITPD20120376A1 (en) * | 2012-12-12 | 2014-06-13 | Automotive Lighting Italia Spa | LIGHTING CIRCUIT, IN PARTICULAR WITH LED LIGHT SOURCES |
-
2020
- 2020-10-22 CN CN202011136959.XA patent/CN113727487B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104185350A (en) * | 2014-09-12 | 2014-12-03 | 南京矽力杰半导体技术有限公司 | Multi-way LED constant current driving circuit and control method thereof |
| CN104822198A (en) * | 2015-04-20 | 2015-08-05 | 南京矽力杰半导体技术有限公司 | Control circuit and control method for multiple paths of LED lamp strings |
| CN111613185A (en) * | 2019-02-26 | 2020-09-01 | 罗姆股份有限公司 | Light emitting element driving device, light emitting element driving system, and light emitting system |
| CN210491278U (en) * | 2019-07-19 | 2020-05-08 | 骆武宁 | Color and light adjusting device for parallel operation of multiple LED high-power driving modules |
| CN210579359U (en) * | 2019-08-30 | 2020-05-19 | 深圳爱克莱特科技股份有限公司 | LED lamp and driving circuit thereof |
| CN110881231A (en) * | 2019-11-27 | 2020-03-13 | 成都芯源系统有限公司 | Dimming circuit and control method thereof |
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