Light emitting diode lamp string system

Abstract

A light-emitting diode lamp string system comprises a light-emitting diode lamp string and a control device, the light-emitting diode lamp string comprises a plurality of light-emitting diode lamps, and each light-emitting diode lamp comprises a first controller, a power circuit, an impedance balancing unit and a plurality of light-emitting diodes. The control device is used for receiving direct current power and comprises a controller, a control switch and an impedance element. When the controller executes a light-emitting mode, the controller switches the control switch to turn on or turn off the control switch. The impedance balancing unit adjusts the impedance of the light-emitting diode lamp to a fixed impedance according to the direct-current power received by the light-emitting diode lamp, so that the voltages of the light-emitting diode lamps are similar. Therefore, the problems that a circuit for generating light-emitting signals by the control device in the light-emitting diode lamp string system is too complicated and the brightness of each light-emitting diode lamp in the light-emitting diode lamp string is not uniform are solved.

Description

Technical Field

[0001] The invention relates to a light emitting diode light string, and in particular to a light emitting diode light string system. Background Art

[0002] Due to the high luminous efficiency, low power consumption, long life, fast response speed and high reliability of LEDs, LEDs have been widely used in many lighting products, such as LED lamps including multiple LEDs and LED light strings including multiple LED lamps.

[0003] The light emission control of each light emitting diode requires external control instructions to change the light emission mode according to the instruction content. However, in order to generate the control instructions, complex electronic circuits are used in the controller of the light string, which further causes a burden on the production cost.

[0004] In addition, the brightness of the LED is determined by the current flowing through the LED; if the current flowing through the LED is larger, the LED will be brighter; if the current flowing through the LED is smaller, the LED will be dimmer. According to Ohm's law, the magnitude of the current is determined by the operating voltage received by the LED light string; if the operating voltage is higher, the current flowing through the LED light string will be larger; if the operating voltage is lower, the current flowing through the LED light string will be smaller.

[0005] However, the LED light string includes a plurality of LED lamps; because the path of transmitting the working voltage to the LED lamps by the LED light string has line loss, the working voltage received by each LED lamp will be inconsistent due to the line loss, resulting in uneven brightness of each LED lamp. Summary of the invention

[0006] To solve the above problems, an object of the present invention is to provide a light emitting diode light string system.

[0007] To achieve the above-mentioned purpose of the present invention, the LED light string system of the present invention comprises: an LED light string, which comprises a plurality of LED lamps electrically connected to each other, wherein each of the LED lamps comprises a first controller and a plurality of LEDs electrically connected to the first controller respectively; and a control device, which is used to receive a DC power and comprises a controller, a power line, a control switch and an impedance element, wherein the control switch is electrically connected to the controller and is arranged on the power line to form a first loop, and the impedance element is connected across the control switch and is arranged on the power line to form a second loop, and the control device is electrically connected to the LED light string via the power line; wherein, when the controller executes a light-emitting mode, the controller The control switch is switched to turn on or off the control switch, so that when the control switch is turned on, the DC power generates a first voltage through the first circuit, and when the control switch is turned off, a second voltage is formed through the second circuit, wherein the first voltage and the second voltage have a voltage difference and form a light-emitting signal, and the first controller of each of the LED lamps identifies the light-emitting signal to drive each of the LEDs to work according to the light-emitting signal; wherein each of the LED lamps further includes: an impedance balancing unit, electrically connected to the first controller and the LED; wherein the impedance balancing unit adjusts the impedance of the LED lamp to a fixed impedance according to the DC power received by the LED lamp, so that the voltage of each of the LED lamps is similar.

[0008] Furthermore, in a specific embodiment of the LED light string system of the present invention as described above, the impedance element is a resistor, a variable resistor or a Zener diode.

[0009] Furthermore, in a specific embodiment of the LED light string system of the present invention as described above, each of the LED lamps further includes: a plurality of first switches, each of the first switches being electrically connected to the first controller and the LED, respectively; a linear controller being electrically connected to the first controller and the LED; a positive terminal being electrically connected to the first controller, the LED and the linear controller; and a negative terminal being electrically connected to the first controller, the first switch and the linear controller, wherein each of the LEDs includes: an anode terminal being electrically connected to the first controller and the linear controller; and a cathode terminal being electrically connected to the first switch, wherein the linear controller linearly adjusts the DC power received from the positive terminal so that the current passing through the LED lamp is a fixed current, so that the brightness of the LED corresponds to the fixed current and is a fixed brightness.

[0010] Furthermore, in a specific embodiment of the LED light string system of the present invention as described above, each of the LED lamps further includes a plurality of impedance balancing units, each of the impedance balancing units is electrically connected to the LED lamp and the first controller respectively, the first controller identifies the light emitting signal to generate a first control signal according to the light emitting signal and transmits the first control signal to each of the first switches to turn on or off each of the first switches, thereby turning on or off each of the LEDs; the impedance balancing unit is controlled by the first controller to have a first equivalent impedance; when the first controller turns on the first switch, the LED and the first switch have a second equivalent impedance; when the first controller turns off the first switch, the impedance balancing unit is synchronously controlled to provide the first equivalent impedance equivalent to the second equivalent impedance to perform an impedance compensation.

[0011] Furthermore, in a specific embodiment of the light-emitting diode light string system of the present invention as described above, each of the impedance balancing units includes: a reverse circuit electrically connected to the first controller; and a bypass switch electrically connected to the reverse circuit, the first controller and the light-emitting diode; wherein the first controller turns on or off the bypass switch in the opposite direction to the first switch through the reverse circuit, so that when the first controller turns off the first switch, the impedance balancing unit provides the first equivalent impedance equivalent to the second equivalent impedance to perform the impedance compensation.

[0012] Furthermore, in a specific embodiment of the LED light string system of the present invention as described above, the first controller of each LED lamp is based on driving each LED to work to synchronously control each impedance balancing unit to perform the impedance compensation, so as to fix the first voltage supplied to the LED lamp by the DC power via the first circuit; when the first controller turns on the first switch, a first current is generated from the anode terminal of the LED to the cathode terminal of the LED; the linear controller controls a cross voltage between the positive terminal and the negative terminal to be a fixed voltage, so as to control the first current to be fixed, so that the brightness of the LED corresponds to the fixed current and is the fixed brightness.

[0013] Furthermore, in a specific embodiment of the light-emitting diode light string system of the present invention as described above, the linear controller includes: a voltage divider circuit, electrically connected to the first controller, the light-emitting diode, the first switch, the bypass switch, the positive terminal and the negative terminal, and generates a divided voltage based on the light-emitting signal; a transistor, coupled between the voltage divider circuit and a ground terminal; and an amplifier, electrically connected to the voltage divider circuit and the transistor; wherein the amplifier includes: a first input terminal, electrically connected to the voltage divider circuit to receive the divided voltage; a second input terminal, receiving a reference voltage; and an output terminal, electrically connected to the transistor; wherein the amplifier provides a second control signal to the transistor based on the divided voltage and the reference voltage to fix the size of a channel of the transistor, and the amplifier adjusts a potential of the negative terminal based on a second current flowing through the transistor, so as to maintain the cross voltage at the fixed voltage by adjusting the potential of the negative terminal.

[0014] Furthermore, in a specific embodiment of the light-emitting diode light string system of the present invention as described above, the linear controller further includes: a constant voltage source, generating a constant voltage; and a voltage follower, electrically connected to the constant voltage source and the second input terminal of the amplifier; wherein the voltage follower electrically isolates and amplifies the constant voltage to generate the reference voltage corresponding to the constant voltage; the voltage follower transmits the reference voltage to the amplifier via the second input terminal of the amplifier.

[0015] Furthermore, in a specific embodiment of the light-emitting diode light string system of the present invention as described above, the voltage-dividing circuit includes: a first voltage-dividing resistor, electrically connected to the first controller, the light-emitting diode, the bypass switch, the positive terminal and the first input terminal of the amplifier; and a second voltage-dividing resistor, electrically connected to the first voltage-dividing resistor, the first input terminal of the amplifier, the transistor, the first controller, the first switch, the bypass switch and the negative terminal.

[0016] Furthermore, in a specific embodiment of the LED light string system of the present invention as described above, each of the impedance balancing units further includes: an equivalent diode impedance element electrically connected to the first controller, the LED and the bypass switch.

[0017] The utility model is to improve the problem that the controller in the LED light string has a complex circuit for generating a light signal and the brightness of each LED lamp is uneven.

[0018] In order to further understand the technology, method and effect of the present invention and achieve the intended purpose of the present invention, please refer to the following detailed description and drawings; in addition, the purpose, characteristics and features of the present invention can be understood more deeply and specifically; however, the drawings are provided only for reference and description and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. 4 is a block diagram of a light emitting diode light string system according to a first embodiment of the present invention.

[0020] Figure 2 FIG. 4 is a circuit block diagram of a light emitting diode lamp according to an embodiment of the present invention.

[0021] Figure 3 FIG. 4 is a waveform diagram of a light emitting signal according to an embodiment of the present invention.

[0022] Figure 4 FIG. 4 is a block diagram of a light emitting diode light string system according to a second embodiment of the present invention.

[0023] Figure 5 The waveform diagram of a light emitting signal being identified as 0 or 1 according to an embodiment of the present invention, wherein the waveform on the left represents 0, and the waveform on the right represents 1.

[0024] Figure 6 FIG. 4 is a block diagram of a light emitting diode light string system according to a third embodiment of the present invention.

[0025] Figure 7 FIG. 4 is a block diagram of a light emitting diode light string system according to a fourth embodiment of the present invention.

[0026] Figure 8 FIG. 4 is a circuit block diagram of a light emitting diode lamp according to another embodiment of the present invention.

[0027] Explanation of symbols in the accompanying drawings:

[0028] 1: first controller;

[0029] 2: Light emitting diode;

[0030] 3: first switch;

[0031] 4: Linear controller;

[0032] 10: LED light string system;

[0033] 20: LED light string;

[0034] 30: control device;

[0035] 42: voltage divider circuit;

[0036] 44: transistor;

[0037] 46: amplifier;

[0038] 50: constant voltage source;

[0039] 52: voltage follower;

[0040] 56: impedance balancing unit;

[0041] 200: light emitting diode lamp;

[0042] 302: DC power;

[0043] 304: controller;

[0044] 306: control switch;

[0045] 308: impedance element;

[0046] 310: power supply line;

[0047] 312: voltage positive terminal;

[0048] 314: negative voltage terminal;

[0049] 562: Reverse circuit;

[0050] 564: bypass switch;

[0051] 566: equivalent diode impedance element;

[0052] CL: frequency signal generator;

[0053] I1: first current;

[0054] I2: second current;

[0055] In1: first input terminal;

[0056] In2: the second input terminal;

[0057] L1: first circuit;

[0058] L2: Second circuit;

[0059] LED+: anode end;

[0060] LED-: cathode end;

[0061] O: output terminal;

[0062] R1: the first voltage dividing resistor;

[0063] R2: the second voltage dividing resistor;

[0064] Re1: first equivalent impedance;

[0065] Re2: second equivalent impedance;

[0066] Sc1: first control signal;

[0067] Sc2: second control signal;

[0068] V: constant voltage;

[0069] V1: first voltage;

[0070] V2: second voltage;

[0071] Vc: cross pressure;

[0072] Vd: voltage difference;

[0073] Vdc: luminous signal;

[0074] VDD: positive terminal;

[0075] VEE: ground terminal;

[0076] Vp: partial pressure;

[0077] Vref: reference voltage;

[0078] VSS: Negative terminal. DETAILED DESCRIPTION

[0079] In the present invention, many specific details are provided to provide a comprehensive understanding of the embodiments of the present invention; however, those skilled in the art will appreciate that the present invention can be practiced without one or more of these specific details; in other cases, well-known details are not shown or described to avoid obscuring the features of the present invention. The technical content and detailed description of the present invention are as follows, and are illustrated with the accompanying drawings.

[0080] Please refer to Figure 1 , which is a block diagram of an LED light string system 10 according to a first embodiment of the present invention. The LED light string system 10 of the present invention comprises an LED light string 20 and a control device 30. The LED light string 20 comprises a plurality of LED lamps 200. The control device 30 comprises a controller 304, a power circuit 310, a control switch 306 and an impedance element 308. The power circuit 310 comprises at least a positive voltage terminal 312 and a negative voltage terminal 314. The above-mentioned elements are electrically connected to each other, and Figure 1 The LED lamps 200 are shown to be connected in series.

[0081] The control device 30 is used to receive a DC power 302. The control switch 306 is disposed on the power line 310 to form a first loop L1. The impedance element 308 is connected across the control switch 306 and disposed on the power line 310 to form a second loop L2. The impedance element 308 is a resistor, a variable resistor or a Zener diode. Figure 1The control switch 306 is a P-type metal oxide semi-conductor field effect transistor (P-MOSFET), and the control switch 306 and the impedance element 308 are disposed at the voltage positive terminal 312 .

[0082] Please refer to Figure 2 , which is a circuit block diagram of the light emitting diode lamp 200 according to an embodiment of the present invention; Figure 2 The components shown are Figure 1 The components shown are the same, and for the sake of simplicity, their description will not be repeated here, and Figure 2 The circuit is used when the LED lamps 200 are connected in series. Each LED lamp 200 includes a first controller 1, a plurality of impedance balancing units 56 (for simplicity, Figure 2 Only one is shown), several LEDs 2 (for simplicity, Figure 2 Only one is shown), several first switches 3 (for simplicity, Figure 2 Only one is shown), a linear controller 4, a frequency signal generator CL, a positive terminal VDD and a negative terminal VSS, each of the impedance balancing units 56 includes a reverse circuit 562, a bypass switch 564 and an equivalent diode impedance element 566, each of the light-emitting diodes 2 includes an anode terminal LED+ and a cathode terminal LED-, the linear controller 4 includes a voltage divider circuit 42, a transistor 44, an amplifier 46, a constant voltage source 50 and a voltage follower 52, the amplifier 46 includes a first input terminal In1, a second input terminal In2 and an output terminal O, the voltage divider circuit 42 includes a first voltage divider resistor R1 and a second voltage divider resistor R2, the above-mentioned elements are electrically connected to each other, and the transistor 44 is coupled between the voltage divider circuit 42 and a ground terminal VEE. The impedance balancing unit 56 adjusts the impedance of the LED lamp 200 to a fixed impedance according to the DC power 302 received by the LED lamp 200 , so that the voltage of each LED lamp 200 is similar.

[0083] Please refer to Figure 3 , which is a waveform diagram of the light emitting signal Vdc according to an embodiment of the present invention; and please also refer to Figure 1 as well as Figure 2When the controller 304 executes a lighting mode, the controller 304 switches the control switch 306 to turn on or off the control switch 306, so that the DC power 302 generates a first voltage V1 through the first loop L1 when the control switch 306 is turned on, and forms a second voltage V2 through the second loop L2 when the control switch 306 is turned off, wherein the first voltage V1 and the second voltage V2 have a voltage difference Vd and form a lighting signal Vdc, and the first controller 1 of each of the LED lamps 200 identifies the lighting signal Vdc to drive each of the LEDs 2 to work according to the lighting signal Vdc, and the first controller 1 of each of the LED lamps 200 synchronously controls each of the impedance balancing units 56 to perform an impedance compensation based on driving each of the LEDs 2 to work, so as to fix the first voltage V1 supplied to the LED lamp 200 by the DC power 302 through the first loop L1.

[0084] The first controller 1 of each of the LED lamps 200 identifies the light signal Vdc to generate a first control signal Sc1 according to the light signal Vdc and transmits the first control signal Sc1 to each of the first switches 3 to turn on or off each of the first switches 3, thereby turning on or off each of the LEDs 2; the impedance balancing unit 56 is controlled by the first controller 1 to have a first equivalent impedance Re1; when the first controller 1 turns on the first switch 3, the LED 2 and the first switch 3 have a second equivalent impedance Re2; when the first controller 1 turns off the first switch 3, the first controller 1 synchronously controls the impedance balancing unit 56 to provide the first equivalent impedance Re1 equivalent to the second equivalent impedance Re2 for impedance compensation. The equivalent diode impedance element 566 (e.g., a diode) can make the first equivalent impedance Re1 more equivalent to the second equivalent impedance Re2.

[0085] The first controller 1 turns on or off the bypass switch 564 in the opposite direction of the first switch 3 via the reverse circuit 562, so that when the first controller 1 turns off the first switch 3, the impedance balancing unit 56 provides the first equivalent impedance Re1 equivalent to the second equivalent impedance Re2 for impedance compensation.

[0086] Among them, because the linear controller 4 has the function of linearly adjusting and controlling the input power when it changes and maintaining the power passing through the LED lamp 200 as a constant power (such as a constant voltage or a constant current), when the DC power 302 received from the positive terminal Vdd changes, the linear controller 4 will linearly adjust the DC power 302 so that the current passing through the LED lamp 200 is a fixed current, so that the brightness of the LED 2 corresponds to the fixed current and is a fixed brightness. The specific method is described in detail below.

[0087] When the first controller 1 turns on the first switch 3, a first current I1 is generated from the anode terminal LED+ of the light-emitting diode 2 to the cathode terminal LED- of the light-emitting diode 2; the linear controller 4 controls a cross voltage Vc between the positive terminal VDD and the negative terminal VSS to be a fixed voltage to control the first current I1 to be fixed, so that the brightness of the light-emitting diode 2 corresponds to the fixed current and is the fixed brightness.

[0088] The voltage divider circuit 42 generates a divided voltage Vp based on the light-emitting signal Vdc; the constant voltage source 50 is used to generate a constant voltage V; the voltage follower 52 electrically isolates and amplifies the constant voltage V to generate a reference voltage Vref corresponding to the constant voltage V; the voltage follower 52 transmits the reference voltage Vref to the amplifier 46 via the second input terminal In2 of the amplifier 46; the second input terminal In2 receives the reference voltage Vref; the amplifier 46 provides a second control signal Sc2 with a linear variation characteristic to the transistor 44 based on the divided voltage Vp and the reference voltage Vref to fix the size of a channel of the transistor 44; in other words, the channel of the transistor 44 is controlled within the linear region according to the linear variation characteristic of the second control signal Sc2, and a potential of the negative terminal VSS is adjusted through the size of the channel of the transistor 44, so as to maintain the cross voltage Vc at the fixed voltage by adjusting the potential of the negative terminal VSS. Specifically, since the second control signal Sc2 controls the gate-source voltage (usually referred to as Vgs) of the transistor 44 to be fixed, the drain-source voltage (usually referred to as Vds) of the transistor 44 is affected by a second current I2 (i.e., drain current, usually referred to as Id) flowing through the transistor 44, so that the potential of the negative terminal VSS is adjusted. Therefore, by adjusting the potential of the negative terminal VSS, the cross voltage Vc between the positive terminal VDD and the negative terminal VSS can be maintained at the fixed voltage (for example but not limited to 3 volts) and further control the first current I1 to be fixed.

[0089] Please refer to Figure 4 , which is a block diagram of a light emitting diode light string system 10 according to a second embodiment of the present invention; Figure 4 The components shown are Figure 1 The components shown are the same and their description will not be repeated here for the sake of brevity. Figure 4 The LED light string system 10 shown includes a plurality of LED light strings 20 connected to each other.

[0090] Please refer to Figure 5 , which is a waveform diagram of the light emitting signal Vdc being identified as 0 or 1 according to an embodiment of the present invention; and please also refer to Figure 1 , Figure 2 as well as Figure 3 The first controller 1 uses the aforementioned voltage division and the amplifier 46 to use the frequency provided by the frequency signal generator CL to determine the duration of the waveform of the light emitting signal Vdc, thereby reading the carrier signal (that is, the light emitting signal Vdc) to determine whether the light emitting signal Vdc is 0 or 1. For example, Figure 5 The waveform on the left represents 0, while the waveform on the right represents 1.

[0091] Please refer to Figure 6 , which is a block diagram of a light emitting diode light string system 10 according to a third embodiment of the present invention; Figure 6 The components shown are Figure 1 The components shown are the same, and for the sake of brevity, their description will not be repeated here. Figure 6 The LED lamps 200 are connected in parallel.

[0092] Please refer to Figure 7 , which is a block diagram of a light emitting diode light string system 10 according to a fourth embodiment of the present invention; Figure 7 The components shown are Figure 6 The components shown are the same, and for the sake of brevity, their description will not be repeated here. Figure 7 The control switch 306 is an N-type metal oxide semiconductor field effect transistor (N-MOSFET), and the control switch 306 and the impedance element 308 are disposed at the negative voltage terminal 314 .

[0093] Please refer to Figure 8 , which is a circuit block diagram of a light emitting diode lamp 200 according to another embodiment of the present invention; Figure 8 The components shown are Figure 2 The components shown are the same, and for the sake of simplicity, their description will not be repeated here, and Figure 8 The circuit is used when the LED lamps 200 are connected in parallel. If the LED lamps 200 are connected in parallel, since the voltage of the positive terminal VDD of each LED lamp 200 is fixed, and the voltage of the negative terminal VSS of each LED lamp 200 is also fixed, there is no need for Figure 2 The impedance balancing unit 56 is shown.

[0094] The present invention has at least the following two effects:

[0095] 1. Improve the problem that the circuit of the control device 30 in the LED light string system 10 generating the light emitting signal Vdc is too complicated. The single impedance element 308 is connected in parallel to the two ends of the control switch 306, and the controller 304 operates the on or off state of the control switch 306, so that the DC power 302 has the first voltage V1 and the second voltage V2 to generate the light emitting signal Vdc; compared with the previous technology, the technical solution adopted by the present invention is simpler and has a lower cost.

[0096] 2. Improve the problem of uneven brightness of each LED lamp 200 in the LED lamp string 20. By means of the impedance element 308 and the linear controller 4, the present invention can make the first voltage V1 stable as a constant voltage when the light signal Vdc changes between the first voltage V1 and the second voltage V2, so that each LED 2 can work normally and stably, and the first controller 1 can normally identify the light signal Vdc. Therefore, the present invention has a simple structure and can achieve the effect of stabilizing the first voltage V1.

[0097] Although the present invention has been described with reference to the embodiments of the present invention, it should be understood that the present invention is not limited to its details; various substitutions and modifications have been proposed in the foregoing description, and other substitutions and modifications will occur to a person skilled in the art; therefore, all such substitutions and modifications are intended to be included within the scope of the present invention.

Claims

1. A light emitting diode light string system, characterized in that: Include: An LED light string, comprising a plurality of LED lights electrically connected to each other, wherein each of the LED lights comprises a first controller and a plurality of LEDs electrically connected to the first controller respectively; as well as a control device, the control device is used to receive direct current power and comprises a controller, a power line, a control switch and an impedance element, the control switch is electrically connected to the controller and is disposed on the power line to form a first loop, the impedance element is connected across the control switch and is disposed on the power line to form a second loop, and the control device is electrically connected to the light emitting diode lamp string via the power line; When the controller executes a light-emitting mode, the controller switches the control switch to turn on or off the control switch, so that when the control switch is turned on, the DC power generates a first voltage through the first circuit, and when the control switch is turned off, a second voltage is formed through the second circuit, wherein the first voltage and the second voltage have a voltage difference and form a light-emitting signal, and the first controller of each of the light-emitting diode lamps identifies the light-emitting signal to drive each of the light-emitting diodes to work according to the light-emitting signal; Wherein, each of the light emitting diode lamps further comprises: an impedance balancing unit electrically connected to the first controller and the light emitting diode; The impedance balancing unit adjusts the impedance of the LED lamp to a fixed impedance according to the DC power received by the LED lamp, so that the voltage of each LED lamp is close.

2. The LED light string system according to claim 1, characterized in that: The impedance element is a resistor, a variable resistor or a Zener diode.

3. The LED light string system according to claim 1, characterized in that: Each of the LED lamps further comprises: a plurality of first switches, each of the first switches being electrically connected to the first controller and the LED; a linear controller electrically connected to the first controller and the light emitting diode; a positive terminal electrically connected to the first controller, the light emitting diode and the linear controller; and a negative terminal electrically connected to the first controller, the first switch and the linear controller, Wherein, each of the light emitting diodes comprises: an anode terminal electrically connected to the first controller and the linear controller; and a cathode terminal electrically connected to the first switch, The linear controller linearly adjusts the DC power received from the positive terminal so that the current passing through the LED lamp is a fixed current, so that the brightness of the LED corresponds to the fixed current and is a fixed brightness.

4. The LED light string system according to claim 3, characterized in that: Each of the light-emitting diode lamps further includes a plurality of impedance balancing units, each of which is electrically connected to the light-emitting diode lamp and the first controller respectively. The first controller identifies the light-emitting signal to generate a first control signal according to the light-emitting signal and transmits the first control signal to each of the first switches to turn on or off each of the first switches, thereby turning on or off each of the light-emitting diodes. The impedance balancing unit is controlled by the first controller to have a first equivalent impedance. When the first controller turns on the first switch, the light-emitting diode and the first switch have a second equivalent impedance. When the first controller turns off the first switch, the impedance balancing unit is synchronously controlled to provide the first equivalent impedance equivalent to the second equivalent impedance to perform impedance compensation.

5. The LED light string system according to claim 4, characterized in that: Each of the impedance balancing units includes: a reverse circuit electrically connected to the first controller; and a bypass switch electrically connected to the reverse circuit, the first controller and the light emitting diode; The first controller turns on or off the bypass switch in the opposite direction of the first switch through the reverse circuit, so that when the first controller turns off the first switch, the impedance balancing unit provides the first equivalent impedance equivalent to the second equivalent impedance for impedance compensation.

6. The LED light string system according to claim 5, characterized in that: The first controller of each of the light-emitting diode lamps is based on driving each of the light-emitting diodes to synchronously control each of the impedance balancing units to perform the impedance compensation, so as to fix the first voltage supplied to the light-emitting diode lamp by the DC power via the first circuit; when the first controller turns on the first switch, a first current is generated from the anode terminal of the light-emitting diode to the cathode terminal of the light-emitting diode; the linear controller controls a cross-voltage between the positive terminal and the negative terminal to be a fixed voltage, so as to control the first current to be fixed, so that the brightness of the light-emitting diode corresponds to the fixed current and is the fixed brightness.

7. The LED light string system according to claim 6, characterized in that: The linear controller contains: a voltage divider circuit electrically connected to the first controller, the light emitting diode, the first switch, the bypass switch, the positive terminal and the negative terminal, and generating a divided voltage based on the light emitting signal; a transistor coupled between the voltage divider circuit and a ground terminal; and an amplifier electrically connected to the voltage divider circuit and the transistor; The amplifier comprises: a first input terminal electrically connected to the voltage divider circuit to receive the divided voltage; a second input terminal, receiving a reference voltage; and an output terminal electrically connected to the transistor; The amplifier provides a second control signal to the transistor based on the divided voltage and the reference voltage to fix the size of a channel of the transistor, and the amplifier adjusts a potential of the negative terminal based on a second current flowing through the transistor to maintain the cross voltage at the fixed voltage by adjusting the potential of the negative terminal.

8. The LED light string system according to claim 7, characterized in that: The linear controller further comprises: A certain voltage source generates a certain voltage; and a voltage follower electrically connected to the constant voltage source and the second input terminal of the amplifier; The voltage follower performs electrical isolation and amplification on the constant voltage to generate the reference voltage corresponding to the constant voltage; the voltage follower transmits the reference voltage to the amplifier via the second input terminal of the amplifier.

9. The LED light string system according to claim 8, characterized in that: The voltage divider circuit includes: a first voltage-dividing resistor electrically connected to the first controller, the light-emitting diode, the bypass switch, the positive terminal and the first input terminal of the amplifier; and A second voltage-dividing resistor is electrically connected to the first voltage-dividing resistor, the first input terminal of the amplifier, the transistor, the first controller, the first switch, the bypass switch and the negative terminal.

10. The LED light string system according to claim 9, characterized in that: Each of the impedance balancing units further includes: an equivalent diode impedance element electrically connected to the first controller, the light emitting diode and the bypass switch.

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