Adjustable control circuit of LED lamp string matching resistor

Abstract

The utility model discloses an adjustable control circuit of an LED lamp string matching resistor, comprising a control decoder used for collecting fixed address information of a driving chip and sending temporary address information and a color code instruction to the driving chip; each LED lamp string circuit is provided with a driving chip and an LED light-emitting unit, the driving chip is provided with an LED driving end and a signal control end, the signal control end is electrically connected with the control decoder, the LED driving end is electrically connected with the LED light-emitting unit, and the signal control end is further electrically connected with a matched resistor; wherein the driving chip is configured to generate and send a corresponding control instruction to the driving chip based on the fixed address information received by the control decoder according to the fixed address information so as to control the on / off of the matched resistor. According to the utility model, through the above design, display faults of the LED lamp string circuit caused by weak control signals received by the driving chip due to signal reflection can be prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of LED display, in particular to an LED lamp string matching resistor circuit. Background Art

[0002] With the continuous advancement of technology, large display screens are usually installed outdoors or indoors to display images for people to watch. Such large display screens are usually composed of a large number of LED light-emitting diodes connected in series, and there is usually a signal line inside to control each LED light-emitting diode.

[0003] But the problem is that due to the existence of different impedances in the circuit, the impedance does not match the signal, which will cause signal reflection on the signal line. This phenomenon is a physical phenomenon that is difficult to avoid. The current solution on the market is to add an external matching resistor at the end of each LED series circuit. The resistance value of the external resistor needs to be matched multiple times to achieve the corresponding effect. At the same time, since adding an external resistor at the end of the LED parallel circuit will cause the signal to decay, the signal at the end is relatively weak, which affects the reception of the driver chip, resulting in an erroneous signal, which is not conducive to the control of the LED light string.

[0004] Therefore, people in this field need to solve the above problems urgently. Utility Model Content

[0005] In order to solve the technical defects raised in the above-mentioned background technology, the purpose of the utility model is to provide an LED light string matching resistor circuit, which can prevent the LED light string circuit from causing display failure due to the weakening of the control signal received by the driver chip due to signal reflection, and avoid the traditional method of adding an external resistor at the end of the LED parallel circuit, which leads to poor scalability.

[0006] The utility model adopts the following technical solution: an adjustable control circuit of a matching resistor of an LED light string, comprising:

[0007] A control decoder is used to collect fixed address information of the driver chip and send temporary address information and color code instructions to the driver chip;

[0008] At least one LED light string circuit, each of which has a driver chip and an LED light-emitting unit, the driver chip has an LED driver end and a signal control end, the signal control end is electrically connected to the control decoder, the LED driver end is electrically connected to the LED light-emitting unit, and the signal control end is also electrically connected to a matching resistor;

[0009] Wherein, the driving chip is configured to: generate and send corresponding control instructions to the driving chip based on the fixed address information received by the control decoder and according to the fixed address information to control the on / off of the matching resistor.

[0010] Optionally, one end of the matching resistor is electrically connected to pin 7 of the driver chip, and the other end is grounded, and the matching resistor is used to absorb the reflected current generated by the control decoder.

[0011] Optionally, the matching resistor is a pull-down resistor with a resistance value of 5 kilo-ohms.

[0012] Optionally, the LED light emitting unit includes:

[0013] A red LED light-emitting subunit comprises a red LED light-emitting diode and a first resistor connected in series, wherein one end of the first resistor is electrically connected to pin 2 of the driving chip, and the other end of the first resistor is electrically connected to the red LED light-emitting diode;

[0014] A green LED light-emitting subunit, comprising a green LED light-emitting diode and a second resistor connected in series, wherein one end of the second resistor is electrically connected to pin 3 of the driving chip, and the other end is electrically connected to the green LED light-emitting diode;

[0015] A blue LED light-emitting subunit comprises a blue LED light-emitting diode and a third resistor connected in series, one end of the third resistor is electrically connected to the 4th pin of the driving chip, and the other end is electrically connected to the blue LED light-emitting diode;

[0016] The white LED light-emitting subunit comprises a white LED light-emitting diode and a fourth resistor connected in series, one end of the fourth resistor is electrically connected to the 5-pin of the driving chip, and the other end is electrically connected to the white LED light-emitting diode.

[0017] Optionally, the driver chip also has a signal input terminal and a signal output terminal, the signal output terminal of the first driver chip is electrically connected to the control decoder, and the signal input terminal is electrically connected to the signal output terminal of the next driver chip, the signal output terminal of the first driver chip is used to send a fixed address to the control decoder, and the signal input terminal is used to receive a fixed address sent by the next driver chip.

[0018] In summary, the beneficial effects of the utility model are:

[0019] By setting the control decoder to be electrically connected with the driver chip, the control decoder can collect the fixed address information of the driver chip, so as to obtain the specific position of each driver chip, and then reset the address of its driver chip by sending a temporary address, so as to facilitate the control decoder to find the driver chip, and can control the corresponding driver chip by sending a control instruction, so as to turn on / off its matching resistor, and then control the matching resistor, so as to absorb the reflected current generated by the control decoder, avoiding the driver chip from receiving the signal of its color code instruction, so as to make the LED light string circuit display accordingly as needed.

[0020] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a circuit diagram of an embodiment of the utility model.

[0022] Description of reference numerals in the figures:

[0023] 1. Control decoder; 2. LED light string circuit; 21. Driver chip; 22. LED light-emitting unit; 221. Red LED light-emitting subunit; 222. Green LED light-emitting subunit; 223. Blue LED light-emitting subunit; 224. White LED light-emitting subunit; 3. Matching resistor; D1. Red LED light-emitting diode; R1. First resistor; D2. Green LED light-emitting diode; R2. Second resistor; D3. Blue LED light-emitting diode; R3. Third resistor; D4. White LED light-emitting diode; R4. Fourth resistor. DETAILED DESCRIPTION

[0024] In order to make the content of the utility model more clearly understood, the utility model is further described below based on specific embodiments in combination with the accompanying drawings.

[0025] It should be noted that the terms "center", "upper", "lower", "front", "back", "left", "right", "inner", "outer" and the like used herein to indicate directions or positional relationships are based on directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. Unless otherwise specified, "plurality" means two or more.

[0026] Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood by specific circumstances.

[0027] like Figure 1 As shown, an adjustable control circuit of an LED light string matching resistor 3 includes a control decoder 1 and at least one LED light string circuit 2. The control decoder 1 is used to collect fixed address information of a driver chip 21 and send temporary address information and color code instructions to the driver chip 21; each LED light string circuit 2 has a driver chip 21 and a plurality of LED light-emitting units 22, the driver chip 21 has an LED driver end and a signal control end, the signal control end is electrically connected to the DATA pin of the control decoder 1, the LED driver end is electrically connected to the LED light-emitting unit 22, and the signal control end is also electrically connected to the matching resistor 3; wherein the driver chip 21 is configured to: based on the fixed address information received by the control decoder 1 and according to the fixed address information, generate and send corresponding control instructions to the driver chip 21 to control the on / off of the matching resistor 3.

[0028] In an embodiment of the present application, the control decoder 1 has four channels, namely a power channel, a ground line, a signal line and an address line. The control decoder 1 is electrically connected to the driver chip 21 of the first LED light string circuit 2. The control decoder 1 is used to collect the fixed address information of the driver chip 21. After collecting the fixed address information, the control decoder 1 will send temporary address information and color code instructions.

[0029] Specifically, each driver chip 21 contains 48 bits of information, including 29 bits of fixed address information (obtained by laser trimming) + 1 bit of matching resistor 3 bits + 10 bits of temporary address information + 2 bits of red abnormal feedback information + 2 bits of green abnormal feedback information + 2 bits of blue abnormal feedback information, 2 bits of it's white abnormal feedback information, 1bit of matching resistor 3 bits and 10bit of temporary address information are initialized when each chip is 0. After the above-mentioned LED light string circuit 2 completes the electrical connection, the control decoder 1 will send a low level of 80us through the signal line. When each driver chip 21 receives the low level signal, it will start to reset and then send a 2us square wave signal. After the driver chip 21 receives the 2us square wave signal, it starts to send fixed address information to the control decoder 1. When each driver chip 21 receives the first square wave, for example, chip No. 1 will send the first high-bit fixed address code to the control decoder 1, and chip No. 2 will send its own first high-bit fixed address code to chip No. 1. After sending 48 square waves, the fixed address information of chip No. 1 will all be sent to the control decoder 1, and the fixed address information of chip No. 2 will all be sent to chip No. 1. Continue to send the 49th-96th square waves. At this time, the information of chip No. 2 will be sent to the control decoder 1 through chip No. 1.

[0030] Furthermore, if Figure 1 As shown, each LED light string circuit 2 has a driver chip 21 and an LED light emitting unit 22. In the embodiment of the utility model, N LED light string circuits 2 may be included, wherein each LED light string circuit 2 has a driver chip 21 and an LED light emitting unit 22. By electrically connecting the driver chip 21 and the LED light emitting unit 22, the driver chip 21 can control the LED light emitting unit 22 to emit light, thereby realizing screen display. The driver chip 21 has an LED driver end and a signal control end. The LED light emitting unit 22 is electrically connected to the LED driver end, and the signal control end is electrically connected to the control decoder 1, thereby being able to pass The control decoder 1 controls the LED light-emitting unit 22 to display different colors through the signal control end, and the signal control end is also electrically connected to the matching resistor 3; it should be understood that since signal reflection will occur on the channel connecting the driver chip 21 and the control decoder 1, this is caused by the different impedances in the circuit. This signal reflection phenomenon will affect the driver chip 21 receiving the control signal of the control decoder 1, and by electrically connecting a 5 kilo-ohm pull-down resistor to the signal control end and grounding the resistor, the reflected current can be absorbed, thereby avoiding the occurrence of signal reflection, thereby improving the signal reception of the driver chip 21.

[0031] Optional, such as Figure 1As shown, one end of the matching resistor 3 is electrically connected to pin 1 of the driving chip 21 , and the other end is grounded. The matching resistor 3 is used to absorb the reflected current generated by the control decoder 1 .

[0032] In the embodiment of the present application, one end of the matching resistor 3 is electrically connected to the driving pin 7 and the other end is grounded, so that the reflected current generated by the control decoder 1 can be absorbed, thereby avoiding affecting the control signal reception of the driving chip 21.

[0033] Optional, such as Figure 1 As shown, the LED light-emitting unit 22 includes a red LED light-emitting subunit 221, a green LED light-emitting subunit 222, a blue LED light-emitting subunit 223 and a white LED light-emitting subunit 224. The red LED light-emitting subunit 221 has a red LED light-emitting diode D1 and a first resistor R1 connected in series. One end of the first resistor R1 is electrically connected to the 2nd pin of the driving chip 21, and the other end is electrically connected to the red LED light-emitting diode D1. The green LED light-emitting subunit 222 has a green LED light-emitting diode D2 and a second resistor R2 connected in series. One end of the second resistor R2 is electrically connected to the red LED light-emitting diode D1. The blue LED light-emitting subunit 223 has a blue LED light-emitting diode D3 and a third resistor R3 connected in series, one end of the third resistor R3 is electrically connected to pin 4 of the driver chip 21, and the other end is electrically connected to the blue LED light-emitting diode D3; the white LED light-emitting subunit 224 has a white LED light-emitting diode D4 and a fourth resistor R4 connected in series, one end of the fourth resistor R4 is electrically connected to pin 5 of the driver chip 21, and the other end is electrically connected to the white LED light-emitting diode D4.

[0034] In the embodiment of the present application, it can be understood that the red LED light-emitting subunit 221 can be composed of N red LED light-emitting diodes D1 connected in series, and a first resistor R1 is also connected in parallel between the driver chip 21 and the LED light-emitting diode, and one end of the first resistor R1 is electrically connected to the 2 pin of the driver chip 21, and the other end is electrically connected to the red LED light-emitting diode D1. By setting the first resistor R1, it can be ensured that the red LED diode obtains a stable current to prevent overcurrent from damaging the LED, and at the same time, it can also play a role in current limiting protection of the LED to prevent excessive current from damaging the red LED diode;

[0035] The green LED light-emitting subunit 222 can also be composed of N green LED light-emitting diodes D2 connected in series. A second resistor R2 is also connected in parallel between the driver chip 21 and the green LED light-emitting diode D2. One end of the second resistor R2 is electrically connected to the 3-pin of the driver chip 21, and the other end is electrically connected to the green LED light-emitting diode D2. By setting the second resistor R2, it can be ensured that the green LED diode obtains a stable current to prevent overcurrent from damaging the LED. At the same time, it can also play a role in current limiting to protect the LED, preventing excessive current from damaging the green LED diode.

[0036] The above-mentioned blue LED light-emitting subunit 223 can also be composed of N blue LED light-emitting diodes D3 connected in series. A third resistor R3 is also connected in parallel between the driver chip 21 and the blue LED light-emitting diode D3. One end of the third resistor R3 is electrically connected to the 4-pin of the driver chip 21, and the other end is electrically connected to the blue LED light-emitting diode D3. By setting the third resistor R3, it can be ensured that the blue LED diode obtains a stable current to prevent overcurrent from damaging the blue LED diode. At the same time, it can also play a role in current limiting protection of the LED to prevent excessive current from damaging the blue LED diode.

[0037] The above-mentioned white LED light-emitting subunit 224 can also be composed of N white LED light-emitting diodes D4 connected in series. A fourth resistor R4 is also connected in parallel between the driving chip 21 and the white LED light-emitting diode D4. One end of the fourth resistor R4 is electrically connected to pin 5 of the driving chip 21, and the other end is electrically connected to the blue LED light-emitting diode D3. By setting the fourth resistor R4, it can be ensured that the white LED diode obtains a stable current to prevent overcurrent from damaging the blue LED diode. At the same time, it can also play a role in current limiting and protecting the white LED diode to prevent excessive current from damaging the white LED diode.

[0038] Optional, such as Figure 1 As shown, the driver chip 21 also has a signal input end and a signal output end. The signal output end of the first driver chip 21 is electrically connected to the control decoder 1, and the signal input end is electrically connected to the signal output end of the next driver chip 21. The signal output end of the first driver chip 21 is used to send a fixed address to the control decoder 1, and the signal input end is used to receive a fixed address sent by the next driver chip 21.

[0039] In the embodiment of the present application, the first driver chip 21 is electrically connected to the signal output terminal of the next driver chip 21 by setting a signal input terminal, so that the fixed address information of each driver chip 21 can be sent to the previous driver chip 21, and the signal output terminal is electrically connected to the control decoder 1, and can receive temporary address information and color code instructions sent by the control decoder 1, so that the color of each LED light string circuit 2 can be changed under the control of the control decoder 1, so as to achieve a display effect, and by sending temporary address information, the control decoder 1 can locate the required LED light string circuit 2, so that the matching resistor 3 can be turned on or off, thereby preventing the occurrence of reflected current, avoiding the driver chip 21 from receiving the control signal, and preventing abnormal current in a certain LED light string.

[0040] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An adjustable control circuit for matching resistance of LED light string, characterized in that: include: A control decoder is used to collect fixed address information of the driver chip and send temporary address information and color code instructions to the driver chip; At least one LED light string circuit, each of which has a driver chip and an LED light-emitting unit, the driver chip has an LED driver end and a signal control end, the signal control end is electrically connected to the control decoder, the LED driver end is electrically connected to the LED light-emitting unit, and the signal control end is also electrically connected to a matching resistor; Wherein, the driving chip is configured to: generate and send corresponding control instructions to the driving chip based on the fixed address information received by the control decoder and according to the fixed address information to control the on / off of the matching resistor.

2. The adjustable control circuit of the LED light string matching resistor according to claim 1, characterized in that: One end of the matching resistor is electrically connected to pin 7 of the driving chip, and the other end is grounded. The matching resistor is used to absorb the reflected current generated by the control decoder.

3. The adjustable control circuit of the LED light string matching resistor according to claim 2, characterized in that: The matching resistor is a pull-down resistor with a resistance value of 5 kilo-ohms.

4. The adjustable control circuit of the LED light string matching resistor according to claim 1, characterized in that: The LED light emitting unit comprises: A red LED light-emitting subunit comprises a red LED light-emitting diode and a first resistor connected in series, wherein one end of the first resistor is electrically connected to pin 2 of the driving chip, and the other end of the first resistor is electrically connected to the red LED light-emitting diode; A green LED light-emitting subunit, comprising a green LED light-emitting diode and a second resistor connected in series, wherein one end of the second resistor is electrically connected to pin 3 of the driving chip, and the other end is electrically connected to the green LED light-emitting diode; A blue LED light-emitting subunit comprises a blue LED light-emitting diode and a third resistor connected in series, one end of the third resistor is electrically connected to the 4th pin of the driving chip, and the other end is electrically connected to the blue LED light-emitting diode; The white LED light-emitting subunit comprises a white LED light-emitting diode and a fourth resistor connected in series, one end of the fourth resistor is electrically connected to the 5-pin of the driving chip, and the other end is electrically connected to the white LED light-emitting diode.

5. The adjustable control circuit of the LED light string matching resistor according to claim 1, characterized in that: The driver chip also has a signal input end and a signal output end. The signal output end of the first driver chip is electrically connected to the control decoder, and the signal input end is electrically connected to the signal output end of the next driver chip. The signal output end of the first driver chip is used to send a fixed address to the control decoder, and the signal input end is used to receive a fixed address sent by the next driver chip.

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