CN110996435A - LED lamp constant current output circuit with self-protection function and constant current control method - Google Patents
LED lamp constant current output circuit with self-protection function and constant current control method Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/06—Details with automatic reconnection
- H02H3/066—Reconnection being a consequence of eliminating the fault which caused disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/20—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
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- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
Abstract
The invention discloses an LED lamp constant current output circuit with a self-protection function, which comprises at least one matrix LED lamp, matrix resistors, a feedback loop and a self-protection circuit, wherein the matrix resistors are the same as the matrix LED lamps in number, the matrix resistors are connected with the matrix LED lamps in series and used for controlling the current balance of the matrix LED lamps by adjusting the voltage drop difference of the LED lamps, the feedback loop is connected with the matrix LED lamps, and the self-protection circuit is connected with the matrix LED lamps through the feedback loop and used for carrying out overvoltage protection and low-voltage automatic recovery on the LED lamps. The invention abandons the traditional switch power supply, operational amplifier and BJT circuit, reduces the use of EMI/switch voltage peak/special switch power supply chip/high frequency transformer and other chips, thus reducing the hardware cost in the design process; in addition, the invention can realize the control of the current balance through a simple resistor, has few components, simple and reliable process and easy popularization.
Description
Technical Field
The invention belongs to the technical field of LED constant current output circuits, and particularly relates to an LED lamp constant current output circuit with a self-protection function and a constant current control method.
Background
Household appliances, such as a range hood, a steam box, an oven and the like, are often provided with LED atmosphere lamps on display panels, and also illumination lamps used in daily life are generally driven by a constant current power supply; the existing constant current circuit is generally an LED constant current circuit based on a switching power supply, is used in high-power occasions, and has the defects of poor EMI effect, prominent switching peak signal, high circuit cost and the like; still another type is an LED constant current circuit based on operational amplifiers and transistors, which is used in low power applications, but which operates with low efficiency, less than 50%.
In addition, the main methods for the current balance control circuit of the matrix LED in the market generally include: the method is simple in form and only needs one constant current chip; however, the dedicated chip is expensive, and in order to satisfy the functions of the chip, more peripheral circuits and unit machines are required, which results in high hardware cost, excessive detection ports, and large temperature influence on the LED current.
Disclosure of Invention
In order to solve the problems, the invention provides the LED lamp constant current output circuit with the self-protection function, and through mutual cooperation of the matrix resistor, the feedback loop and the self-protection circuit, the constant current output is realized, and meanwhile, the automatic recovery of overvoltage protection and low voltage is realized for the LED lamp.
The invention also aims to provide a constant current control method of the LED lamp.
The technical scheme adopted by the invention is as follows:
the matrix resistor and the matrix LED lamp are connected in series and used for controlling the current balance of the matrix LED lamp by adjusting the voltage drop difference of the LED lamp, the feedback loop is connected with the matrix LED lamp, and the self-protection circuit is connected with the matrix LED lamp through the feedback loop and used for carrying out overvoltage protection and low-voltage automatic recovery on the LED lamp.
Preferably, the feedback loop includes a third triode Q3, a collector of the third triode Q3 is connected with the matrix resistor, one path of an emitter of the third triode Q3 is connected with a fourth resistor R4, the other path is connected with a base of a seventh triode Q7, the fourth resistor R4 is connected with a fourteenth resistor R14 and an eighth capacitor C8 in parallel and then grounded, an emitter of the seventh triode Q7 is grounded, one path of a base of the seventh triode Q7 is connected with a base of the third triode Q3 through a tenth resistor R10, one path is connected with the self-protection circuit, the other path is connected with a voltage dividing resistor unit, the voltage dividing resistor unit is connected with the matrix LED lamp, and the base of the seventh triode Q7 is further connected with the ground through a seventh capacitor C7.
Preferably, the voltage-dividing resistance unit includes a sixth resistor R6 and a seventh resistor R7 connected in series, and the sixth resistor R6 and the seventh resistor R7 are respectively connected in parallel with the eighth resistor R8 and the ninth resistor R9.
Preferably, the self-protection circuit comprises a zener diode D1, a negative electrode of the zener diode D1 is connected to the input voltage VBAT, an anode of the zener diode D1 is connected to the ground through a first resistor R1, the other anode of the zener diode D1 is connected to the base of a second transistor Q2 through a fifth resistor R5, the first resistor R1 is connected in parallel to a fourth capacitor C4, an emitter of the second transistor Q2 is connected to the first resistor R1 in common, and a collector of the second transistor Q2 is connected to the feedback loop.
Preferably, the matrix LED lamp comprises at least two LED lamps connected in parallel, the two LED lamps being located at the same ambient temperature for avoiding different temperatures affecting the accuracy of the current.
Preferably, the matrix resistor comprises at least two resistors, the number of the resistors is the same as the number of the LED lamps, and each resistor is connected with one LED lamp in series.
Preferably, any one of the LED lamps is connected in parallel with a capacitor for filtering the LED lamp.
A constant current control method of an LED lamp applies the LED lamp constant current output circuit with the self-protection function, and the method specifically comprises the following steps:
s1, calculating the unbalanced current of the LED lamp;
and S2, controlling the unbalanced current through the parameters influencing the unbalanced current of the LED lamp in the S1.
Preferably, the unbalanced current of the LED lamp is calculated in S1, specifically:
calculating the unbalanced current of the LED lamp by the following formula;
ΔI＝ΔV/R
in the above formula, Δ I is an unbalanced current of the LED lamp, Δ V is a voltage drop difference between adjacent LED lamps, and R is a resistance of the resistor.
Preferably, in S2, the unbalanced current is controlled by the parameters affecting the unbalanced current of the LED lamp in S1, specifically:
and the delta V is a fixed value, and the unbalanced current is controlled through a variable, namely the resistance value of the resistor, so that the unbalanced current meets the precision requirement.
Compared with the prior art, the invention has the following beneficial effects:
(1) the traditional switching power supply, an operational amplifier and a BJT circuit are abandoned, and the use of EMI/switching voltage spike/special switching power supply chip/high-frequency transformer and other chips is reduced, so that the hardware cost in the design process is reduced;
(2) the negative feedback linear LED constant current of the double triodes is adopted, so that the control port resource of a single chip microcomputer is abandoned, the stable self-regulation of the current of the LED lamp is realized, and the development cost is reduced;
(3) the matrix LED lamp is connected with the matrix resistor with certain resistance and precision in series, so that the brightness, the temperature and the current precision of the LED lamp are controlled; the control on the current balance can be realized through a simple resistor, the number of components is small, the process is simple and reliable, and the popularization is easy;
(4) the working voltage of a negative feedback linear LED constant current circuit of the double triodes is controlled by the self-protection circuit, so that an overvoltage protection function and a low-voltage self-recovery function are realized.
Drawings
Fig. 1 is a system block diagram of an LED lamp constant current output circuit with a self-protection function according to embodiment 1 of the present invention;
fig. 2 is a circuit diagram of an LED lamp constant current output circuit with a self-protection function according to embodiment 1 of the present invention;
fig. 3 is a circuit diagram of a matrix LED lamp and a matrix resistor in an LED lamp constant current output circuit with a self-protection function according to embodiment 1 of the present invention;
fig. 4 is a temperature curve diagram of an LED lamp in a constant current output circuit of an LED lamp having a self-protection function according to embodiment 1 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the description of the present invention, it is to be understood that the terms "vertical", "lateral", "longitudinal", "front", "rear", "left", "right", "upper", "lower", "horizontal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description of the present invention, and do not mean that the device or member to which the present invention is directed must have a specific orientation or position, and thus, cannot be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example 1
The embodiment 1 of the invention provides an LED lamp constant current output circuit with a self-protection function, as shown in FIG. 1, the LED lamp constant current output circuit comprises at least one matrix LED lamp 1, matrix resistors 2, a feedback loop 3 and a self-protection circuit 4, wherein the matrix resistors 2 are the same as the matrix LED lamps 1 in number, the matrix resistors 2 and the matrix LED lamps 1 are connected in series and used for controlling current balance of the matrix LED lamps 1 by adjusting voltage drop differences of the LED lamps, the feedback loop 3 is connected with the matrix LED lamps 1, and the self-protection circuit 4 is connected with the matrix LED lamps 1 through the feedback loop 3 and used for performing overvoltage protection and low-voltage automatic recovery on the LED lamps;
thus, by adopting the structure, the constant current output of the LED lamp is realized through the feedback loop 3;
the matrix LED lamp 1 is connected with the matrix resistor 2 with certain resistance and precision in series, so that the brightness, the temperature and the current precision of the LED lamp are controlled;
the arrangement of the self-protection circuit 4 realizes overvoltage protection and low-voltage automatic recovery of the LED lamp.
Specifically, as shown in fig. 2, the feedback loop 3 includes a third transistor Q3, a collector of the third transistor Q3 is connected to the matrix resistor 2, one path of an emitter of the third transistor Q3 is connected to a fourth resistor R4, the other path is connected to a base of a seventh transistor Q7, the fourth resistor R4 is connected in parallel with a fourteenth resistor R14 and an eighth capacitor C8 and then grounded, an emitter of the seventh transistor Q7 is grounded, one path of a base of the seventh transistor Q7 is connected to a base of the third transistor Q3 through a tenth resistor R10, one path is connected to the self-protection circuit 4, the other path is connected to the voltage-dividing resistor unit 31, the voltage-dividing resistor unit 31 is connected to the matrix LED lamp 1, and the base of the seventh transistor Q7 is also grounded through a seventh capacitor C7;
the matrix LED lamp 1 comprises at least two LED lamps 11 connected in parallel, and the two LED lamps 11 are positioned at the same ambient temperature and used for avoiding different temperatures from influencing the accuracy of current;
the environment temperature is 24-26 ℃, and preferably 25 ℃;
thus, according to the variation of the LED "temperature-voltage offset" parameter (as shown in fig. 4), the ambient temperature variation will cause the voltage on the LED lamp 11 to vary; therefore, in order to ensure that the current of the LED lamps 11 is not greatly influenced by the temperature and improve the accuracy, the LED lamps 11 which are connected in parallel should be placed at the same heat source position; and the area of the heat-radiating copper foil is as large as possible so that the position closest to 25 ℃ is the optimal solution (as shown by the dotted line part in figure 4), and the influence of the temperature on the current precision is avoided in this way.
As shown in fig. 3, the matrix resistor 2 includes at least two resistors 21, the number of the resistors 21 is the same as the number of the LED lamps 11, and each of the resistors 21 is connected in series with one LED lamp 11;
moreover, the LED lamps 11 forming the matrix LED lamp 1 are of the same type;
the resistor 21 is a chip resistor.
In this embodiment, the matrix LED lamp 1 is provided in two groups, respectively, a first matrix LED lamp formed by the parallel connection of the fourth diode D4 and the sixth diode D6, and a second matrix LED lamp formed by the parallel connection of the third diode D3 and the fifth diode D5; in order to match the matrix LED lamp 1, the matrix resistor 2 in this embodiment is also provided with two sets, which are a first matrix resistor formed by connecting a twelfth resistor R12 and a sixteenth resistor R16 in parallel and a second matrix resistor formed by connecting an eleventh resistor R11 and a thirteenth resistor R13 in parallel, wherein the fourth diode D4 and the twelfth resistor R12 are connected in series, the sixth diode D6 and the sixteenth resistor R16 are connected in series, the third diode D3 and the eleventh resistor R11 are connected in series, and the fifth diode D5 and the thirteenth resistor R13 are connected in series.
Any one of the LED lamps 11 is connected in parallel with a capacitor for filtering the LED lamp 11;
in order to realize filtering of the LED lamp, in this embodiment, the fourth diode D4 is connected in parallel with the sixth capacitor C6, the sixth diode D6 is connected in parallel with the tenth capacitor C10, the third diode D3 is connected in parallel with the fifth capacitor C5, and the fifth diode D5 is connected in parallel with the ninth capacitor C9.
The principle of the feedback loop 3 for realizing negative feedback linear LED constant current output is as follows:
the voltage dividing resistance unit 31 includes a sixth resistor R6 and a seventh resistor R7 connected in series, and the sixth resistor R6 and the seventh resistor R7 are respectively connected in parallel with the eighth resistor R8 and the ninth resistor R9.
When the current of the LED lamp 11 is set to pass through the parallel resistor of the fourth resistor R4 and the fourteenth resistor R14, the generated voltage makes the seventh triode Q7 be conducted and in an amplification state; at this time, the collector current passing through the seventh triode Q7 is subjected to voltage division by a voltage division resistance unit 31 composed of R6, R7, R8 and R9 to obtain a collector-emitter voltage Vce _ Q7 of the seventh triode Q7, and the third triode Q3 is turned on by a tenth resistor R10; the currents of the LED lamps D3, D4, D5 and D6 continuously pass through the third transistor Q3, so as to establish a normal negative feedback linear LED constant current output circuit.
The self-protection circuit 4 comprises a zener diode D1, the cathode of the zener diode D1 is connected with the input voltage VBAT, the anode of the zener diode is connected with the ground through a first resistor R1 in one way, the other way is connected with the base of a second triode Q2 through a fifth resistor R5, the first resistor R1 is connected with a fourth capacitor C4 in parallel, the emitter of the second triode Q2 is connected with the first resistor R1 in common, and the collector of the second triode Q2 is connected with the feedback loop 3;
thus, the principle of realizing overvoltage protection and low-voltage automatic recovery through the self-protection circuit 4 is as follows:
overvoltage self-protection principle:
when the input voltage VBAT is too high, the zener diode D1 is reverse voltage-stabilized and conducted; the voltage of the first resistor R1 is:
VR1＝VBAT-VD1 (1)
wherein VBAT is the input voltage of the self-protection circuit 4; VR1 is the voltage of the first resistor R1; VD1 is the reverse conducting voltage drop of Zener diode D1; therefore, when the zener diode D1 is turned on in a reverse voltage-stabilizing manner, the base voltage Vbe _ Q2 of the second transistor Q2 becomes saturated and turned on as VR 1; the collector-emitter voltage Vce _ Q2 of the second triode Q2 is VBAT approximately equal to 0V, so that the third triode Q3 is turned off, and the fourth diode D4 is turned off, thereby realizing overvoltage self-protection;
low-pressure self-recovery principle:
after overvoltage protection, when the input voltage VBAT changes from high to low, the Zener diode D1 is cut off in the reverse direction; VR1 ≈ 0V according to formula (1); the second transistor Q2 is off; the third triode Q3 is turned on again, the fourth diode D4 is turned on, and low voltage automatic recovery is achieved.
In another embodiment, when the matrix LED lamp 1 and the matrix resistor 2 are both provided with one, and the number of the LED lamps 11 is two, the two LED lamps 11 are respectively the fourth diode D4 and the sixth diode D6, and the twelfth resistor R12 and the sixteenth resistor R12 are respectively connected in series with the fourth diode D4 and the sixth diode D6, and the twelfth resistor R12 and the sixteenth resistor R16 form the matrix resistor 2;
under the same model of LED lamp 11, the forward conduction voltage drop difference Δ V ═ V based on the same LED currentD4-VD6L, wherein VD4And VD4The voltages at the fourth diode D4 and the sixth diode D6, respectively;
the fourth diode D4 is connected in series with the twelfth resistor R12, the sixth diode D6 is connected in series with the sixteenth resistor R16, and then the D4& R12 are connected in parallel with the D6& R16, so that the parallel voltages of the two are equal, and the maximum forward conduction voltage drop difference Δ V of the matrix LED lamp 1 is equal to the voltages of the twelfth resistor R12 and the sixteenth resistor R16; the following equation is obtained:
VD4+ID4×R12＝VD6+ID6×R16
wherein, ID4And ID6Current to the fourth diode D4 and the sixth diode D6, respectively;
therefore, the method comprises the following steps: the unbalanced current of the matrix LED lamp 1 is Δ I ═ Δ V/R, where Δ I is the unbalanced current of the LED lamp 11, and R is the resistance of the twelfth resistor R12 and the sixteenth resistor R16.
The embodiment abandons the traditional switching power supply, an operational amplifier and a BJT circuit, reduces the use of EMI/switching voltage spike/special switching power supply chip/high-frequency transformer and other chips, and reduces the hardware cost in the design process; the negative feedback linear LED constant current of the double triodes is adopted, so that the control port resource of a single chip microcomputer is abandoned, the stable self-regulation of the current of the LED lamp is realized, and the development cost is reduced; the matrix LED lamp is connected with the matrix resistor with certain resistance and precision in series, so that the brightness, the temperature and the current precision of the LED lamp are controlled; the control on the current balance can be realized through a simple resistor, the number of components is small, the process is simple and reliable, and the popularization is easy; the working voltage of a negative feedback linear LED constant current circuit of the double triodes is controlled by the self-protection circuit, so that an overvoltage protection function and a low-voltage self-recovery function are realized.
Example 2
The embodiment 2 of the invention provides a constant current control method for an LED lamp, which applies the constant current output circuit with the self-protection function of the LED lamp described in the embodiment 1, and the method specifically comprises the following steps:
s1, calculating the unbalanced current of the LED lamp;
and S2, controlling the unbalanced current through the parameters influencing the unbalanced current of the LED lamp in the S1.
Calculating the unbalanced current of the LED lamp in the step S1, specifically:
calculating the unbalanced current of the LED lamp by the following formula;
ΔI＝ΔV/R
in the above formula, Δ I is the unbalanced current of the LED lamp 11, Δ V is the voltage drop difference between adjacent LED lamps 11, and R is the resistance of the resistor 21.
In the step S2, the unbalanced current is controlled by the parameters influencing the unbalanced current of the LED lamp in the step S1, specifically:
Δ V is a fixed value, and the unbalanced current is controlled by a variable, namely the resistance value of the resistor 21, so that the unbalanced current meets the precision requirement.
There are two main factors affecting the current balance.
The first is temperature, and the present embodiment changes according to the LED "temperature-voltage offset" parameter, and the voltage on the LED lamp changes due to the environmental temperature change; therefore, in order to ensure that the current of the LED lamps is not greatly influenced by the temperature and improve the accuracy, the LED lamps which are connected in parallel are placed at the same heat source position; the area of the heat-radiating copper foil is as large as possible, so that the position closest to 25 ℃ is the optimal solution, and the influence of temperature on current precision is avoided in such a way;
the second is the voltage drop difference of the LED lamp, and the embodiment solves the problem of the forward voltage drop error of the matrix LED lamp by serially connecting the matrix LED lamp with the matrix resistor;
therefore, the problem of out-of-control current balance is solved by limiting the ambient temperature of the LED lamp and connecting the matrix resistors in series with the matrix LED lamp.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. The utility model provides a LED lamp constant current output circuit with self preservation protects function, its characterized in that, its includes at least one matrix LED lamp (1), quantity with matrix resistance (2), feedback loop (3) and self preservation protection circuit (4) that matrix LED lamp (1) is the same, matrix resistance (2) and matrix LED lamp (1) are established ties and are used for the current balance through the poor control matrix LED lamp (1) of voltage drop who adjusts the LED lamp, feedback loop (3) and matrix LED lamp (1) are connected, self preservation protection circuit (4) are connected with matrix LED lamp (1) through feedback loop (3) and are used for carrying out overvoltage protection and low pressure automatic recovery to the LED lamp.
2. The constant current output circuit of claim 1, characterized in that the feedback loop (3) comprises a third transistor Q3, the collector of the third transistor Q3 being connected to a matrix resistor (2), one path of an emitting electrode of the third triode Q3 is connected with the fourth resistor R4, the other path of the emitting electrode is connected with the base electrode of the seventh triode Q7, the fourth resistor R4 is connected in parallel with the fourteenth resistor R14 and the eighth capacitor C8 and then grounded, the emitter of the seventh triode Q7 is grounded, one path of a base electrode of the seventh triode Q7 is connected with a base electrode of the third triode Q3 through a tenth resistor R10, one path of the base electrode is connected with the self-protection circuit (4), the other path of the base electrode is connected with the voltage-dividing resistor unit (31), the voltage-dividing resistor unit (31) is connected with the matrix LED lamp (1), and the base electrode of the seventh triode Q7 is grounded through a seventh capacitor C7.
3. The constant current output circuit of the LED lamp with the self-protection function as claimed in claim 2, wherein the voltage dividing resistor unit (31) comprises a sixth resistor R6 and a seventh resistor R7 connected in series, and the sixth resistor R6 and the seventh resistor R7 are respectively connected in parallel with an eighth resistor R8 and a ninth resistor R9.
4. The constant current output circuit of the LED lamp with the self-protection function of claim 3, wherein the self-protection circuit (4) comprises a Zener diode D1, the cathode of the Zener diode D1 is connected with the input voltage VBAT, the anode of the Zener diode D1 is connected with the ground through a first resistor R1, the other circuit of the Zener diode D1 is connected with the base of a second triode Q2 through a fifth resistor R5, the first resistor R1 is connected with a fourth capacitor C4 in parallel, the emitter of the second triode Q2 is connected with the first resistor R1 in common, and the collector of the second triode Q2 is connected with the feedback loop (3).
5. The LED lamp constant current output circuit with the self-protection function according to any one of claims 1 to 4, wherein the matrix LED lamp (1) comprises at least two LED lamps (11) connected in parallel, and the two LED lamps (11) are located at the same ambient temperature for avoiding different temperatures from influencing the accuracy of the current.
6. The LED lamp constant current output circuit with the self-protection function of claim 5, wherein the matrix resistor (2) comprises at least two resistors (21), the number of the resistors (21) is the same as that of the LED lamps (11), and each resistor (21) is connected with one LED lamp (11) in series.
7. The LED lamp constant current output circuit with the self-protection function of claim 6, wherein any one of the LED lamps (11) is connected with a capacitor in parallel for filtering the LED lamp (11).
8. A constant current control method of an LED lamp is characterized in that the constant current output circuit of the LED lamp with the self-protection function, which is disclosed by any one of claims 1 to 7, is applied, and the method specifically comprises the following steps:
s1, calculating the unbalanced current of the LED lamp;
and S2, controlling the unbalanced current through the parameters influencing the unbalanced current of the LED lamp in the S1.
9. The LED lamp constant current control method according to claim 8, wherein the step of calculating the unbalanced current of the LED lamp in S1 specifically comprises the steps of:
calculating the unbalanced current of the LED lamp by the following formula;
ΔI＝ΔV/R
in the formula, delta I is unbalanced current of the LED lamps (11), delta V is voltage drop difference between adjacent LED lamps (11), and R is the resistance value of the resistor (21).
10. The method according to claim 9, wherein the step S2 of controlling the unbalanced current according to the parameters affecting the unbalanced current of the LED lamp in the step S1 is specifically as follows:
and the delta V is a fixed value, and the unbalanced current is controlled through a variable, namely the resistance value of the resistor (21), so that the unbalanced current meets the precision requirement.
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| WO2012022088A1 (en) * | 2010-08-16 | 2012-02-23 | 深圳市航嘉驰源电气股份有限公司 | Current feedback circuit and led lamp driving circuit |
| CN202049714U (en) * | 2010-12-01 | 2011-11-23 | 国琏电子（上海）有限公司 | Light-emitting diode (LED) driving system |
| CN205830093U (en) * | 2016-06-24 | 2016-12-21 | 山东明兴集成电路设计开发有限公司 | A kind of self feed back LED filament and the load of self feed back connection in series-parallel high-voltage LED |
| CN108601158A (en) * | 2018-06-22 | 2018-09-28 | 广州怡泰照明电子科技有限公司 | A kind of linear constant current LED lamp circuit |
| CN211509348U (en) * | 2019-12-16 | 2020-09-15 | 华帝股份有限公司 | LED lamp constant current output circuit with self-protection function |
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