A circuit for controlling an array of LED lamps

Abstract

The utility model discloses a kind of circuit for controlling LED lamp array, for the problem that traditional LED control circuit weak load capacity, MCU pin resource occupies much, system control voltage and load power supply voltage cannot be isolated and lead to poor safety, by shift register realizes series and parallel conversion, only a small amount of SPI data line can control multiple LED signal, significantly reduce MCU pin resource occupation;While using the double voltage framework of control voltage and load power supply voltage isolation, make LED drive circuit can independently provide 5V, 7V or higher voltage, driving capacity is not limited by system control voltage, can carry large power LED array, and control part and load part are electrically isolated, effectively improve system safety and stability, with the advantages of simple circuit structure, low cost and strong expansibility.

Description

Technical Field

[0001] This utility model belongs to the technical field of LED lights, and in particular relates to a circuit for controlling an LED light array. Background Technology

[0002] With the rapid development of LED technology, all kinds of LED lighting products have entered people's daily lives, including lighting, advertising, and decorative light strips.

[0003] Control circuits for LED lights are quite common, but they usually control individual LED lights and often have low power and weak load-carrying capacity. Utility Model Content

[0004] The purpose of this invention is to provide a circuit for controlling an LED array, which can control multiple LEDs simultaneously, greatly reducing the occupancy of MCU control pins, and has a simple structure and low cost.

[0005] To solve the above problems, the technical solution of this utility model is as follows: A circuit for controlling an LED light array, comprising: MCU control unit; A shift register, connected to the MCU control unit, is used to receive serial control signals and convert them into parallel control signals, the parallel control signals including a first control signal and a second control signal; The LED light matrix includes multiple rows of positive control lines and multiple columns of negative control lines. The positive ends of each row of LEDs are connected to the corresponding positive control line, and the negative ends of each column of LEDs are connected to the corresponding negative control line. An LED driving circuit is connected between the shift register and the LED matrix. The LED driving circuit includes a control voltage terminal and a load power supply voltage terminal, which are used to provide the control voltage and the load power supply voltage isolated from the control voltage, respectively. The circuit converts the first control signal and the second control signal into driving signals, which are used on the positive control line and the negative control line, respectively, to selectively light up the LEDs in the matrix.

[0006] According to one embodiment of the present invention, the LED driving circuit includes: The first input terminal is used to receive the second control signal; The second input terminal is used to receive the first control signal; The first switching transistor has its control terminal connected to the first input terminal and its output terminal connected to the control terminal of the second switching transistor. The second switching transistor is connected between the load supply voltage and the LED positive terminal control line, and operates in the cutoff region or saturation region. The third switch has its control terminal connected to the second input terminal and its output terminal connected to the LED negative terminal control line. The control voltage terminal is used to provide the control voltage. The load power supply voltage terminal is used to provide the load power supply voltage, which is isolated from the control voltage; The first and third switching transistors operate in the amplification region.

[0007] According to one embodiment of the present invention, the shift register is connected to the MCU control unit via an SPI interface.

[0008] According to one embodiment of the present invention, the LED light matrix is ​​an N×N matrix, where N is an integer greater than or equal to 2.

[0009] According to one embodiment of the present invention, the first switching transistor is a transistor Q1, whose base is connected to the control voltage, its collector is connected to the control terminal of the second switching transistor, and its emitter is connected to the first input terminal through the fifth resistor R5.

[0010] According to one embodiment of the present invention, the third switching transistor is a transistor Q3, whose base is connected to the second input terminal through a second resistor R3, whose emitter is grounded through a fourth resistor R4, and whose collector is connected to the negative terminal control line.

[0011] According to one embodiment of the present invention, the second switching transistor is a transistor Q2, whose base is connected to the output terminal of the first switching transistor, whose emitter is connected to the load power supply voltage, and whose collector is connected to the positive terminal control line.

[0012] According to one embodiment of the present invention, the second switching transistor is a MOS transistor.

[0013] According to one embodiment of the present invention, an LED and a current-limiting resistor R6 are connected in series between the positive control line and the negative control line.

[0014] According to one embodiment of the present invention, the first control signal is a high-level signal, the second control signal is a low-level signal, and after being converted by the LED driving circuit, the driving signal levels on the positive terminal control line and the negative terminal control line are reversed.

[0015] Because of the adoption of the above technical solution, this utility model has the following advantages and positive effects compared with the prior art: The circuit for controlling an LED array in one embodiment of this utility model addresses the problems of weak load capacity, excessive MCU pin resource usage, and poor safety due to the inability to isolate the system control voltage from the load power supply voltage in traditional LED control circuits. It achieves serial-to-parallel conversion through a shift register, requiring only a few SPI data lines to control multiple LED signals, significantly reducing the MCU pin resource usage. At the same time, it adopts a dual-voltage architecture that isolates the control voltage from the load power supply voltage, allowing the LED driver circuit to independently provide 5V, 7V, or higher voltages. The driving capability is not limited by the system control voltage, enabling it to drive high-power LED arrays. Furthermore, the control part is electrically isolated from the load part, effectively improving system safety and stability. It also has the advantages of simple circuit structure, low cost, and strong scalability. Attached Figure Description

[0016] Figure 1 This is a circuit diagram for controlling an LED lamp array according to one embodiment of the present invention; Figure 2 This is a schematic diagram of an LED driving circuit in one embodiment of the present invention. Detailed Implementation

[0017] The circuit for controlling an LED lamp array according to this utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this utility model will become clearer from the following description and claims.

[0018] Please refer to Figure 1 This embodiment provides a circuit for controlling an LED light array, including: MCU control unit; A shift register, connected to the MCU control unit, is used to receive serial control signals and convert them into parallel control signals, which include a first control signal and a second control signal. The LED light matrix includes multiple rows of positive control lines and multiple columns of negative control lines. The positive ends of each row of LEDs are connected to the corresponding positive control line, and the negative ends of each column of LEDs are connected to the corresponding negative control line. An LED driver circuit is connected between a shift register and an LED matrix. The LED driver circuit includes a control voltage terminal and a load power supply voltage terminal, which are used to provide the control voltage and the load power supply voltage isolated from the control voltage, respectively. It converts the first control signal and the second control signal into drive signals, which are used on the positive control line and the negative control line, respectively, to selectively light up the LEDs in the matrix.

[0019] In other words, the circuit controlling the LED array is mainly divided into three parts: an MCU control unit, a shift register, and an LED driver circuit. The MCU control unit primarily outputs positive and negative signals to control the LEDs' on / off states. The shift register conserves MCU resources by using the SPI port to achieve serial-to-parallel data transmission; the MCU can control eight signals via the four SPI data lines. The LED driver circuit is the core component, mainly responsible for voltage conversion and driving the LEDs. In this embodiment, the LED matrix is ​​an N×N matrix, where N is an integer greater than or equal to 2. For example, in an 8*8 LED matrix, A1~A8 represent the positive terminals controlling eight rows of LEDs, with the positive terminals of each row connected together. B1~B8 represent the negative terminals controlling eight columns of LEDs, with the negative terminals of each column connected together. This acts like a horizontal and vertical coordinate axis; to light up any LED, simply control the corresponding A and B axes.

[0020] The core component, the LED driver circuit, will be described in detail below. This LED driver circuit includes: The first input terminal is used to receive the second control signal; The second input terminal is used to receive the first control signal; The first switching transistor has its control terminal connected to the first input terminal and its output terminal connected to the control terminal of the second switching transistor. The second switching transistor is connected between the load supply voltage and the LED positive terminal control line, and operates in the cutoff region or saturation region. The third switch has its control terminal connected to the second input terminal and its output terminal connected to the LED negative terminal control line. The control voltage terminal is used to provide the control voltage. The load power supply voltage terminal is used to provide the load power supply voltage, which is isolated from the control voltage; Among them, the first and third switching transistors operate in the amplification region.

[0021] For details, please refer to Figure 2 The first input terminal of the LED driver circuit corresponds to Figure 2 The "-" mark on the left indicates that this terminal is used to receive the second control signal (low-level signal 0V) from the shift register; its second input terminal corresponds to... Figure 2 The "+" mark on the left indicates that this terminal is used to receive the first control signal (high-level signal 3.3V) from the shift register. In the LED driver circuit, the control terminals of transistors Q1, Q2, and Q3 are all their bases. By controlling the base current, the conduction and cutoff states of the transistors are controlled, thereby enabling them to operate in the amplification region or the saturation region.

[0022] The first switching transistor is transistor Q1, with its base connected to the control voltage terminal V1, its collector connected to the base of the second switching transistor Q2, and its emitter connected to the first input terminal via the fifth resistor R5. The emitter of transistor Q2 is connected to the load supply voltage terminal V2, and its collector is connected to the collector of the third switching transistor Q3. The base of transistor Q3 is connected to the second input terminal via the third resistor R3, and its emitter is grounded via the fourth resistor R4.

[0023] V1 supplies power to the control components, such as the MCU, shift register, and base voltage of transistor Q1. V2 is the voltage that actually powers the LED load; depending on the LED, it can be 5V, 7V, or other required voltages. R2, R3, R4, and Q3 form a voltage divider to enable transistor Q3's operation, configuring it to operate in the amplification region for current amplification. R6 and D1: D1 represents the LED, and R6 represents the resistance of the LED circuit, which can also be considered the load resistance. Q2 acts as a switch, operating in the cutoff and saturation regions; it can be replaced with a MOSFET. The cutoff region is off, and the saturation region is on. R1, R5, and Q1 enable transistor Q1 to operate in the amplifier mode, achieving current amplification.

[0024] Figure 2 In the diagram, from left to right, + and - are the positive and negative signals output by the MCU through a shift register to control the LED. Assuming the MCU is powered by V1 = 3.3V, the + signal is 3.3V, and the - signal is 0V. When the + signal arrives, transistor Q3 conducts, and with the help of resistors R2, R3, and R4, it operates in the amplification region. The - signal turns on Q1, and with the help of resistors R1 and R5, it also operates in the amplification region. After Q1 conducts, V2 also turns on Q2, which operates in the saturation region, acting as a switch to turn the voltage to the LED on and off. In other words, Q1 and Q3 can be seen as the MCU's positive and negative control switches for the LED, while Q2 can be understood as the LED's physical switch.

[0025] In this embodiment, V2 actually supplies power to the load, and 7V is used. Alternatively, if a larger current is desired, or if the current is not limited by Q2, Q2 can be replaced with a MOSFET, but this will increase the cost slightly, although the load capacity will be improved. If cost is not a concern, transistor Q2 can be replaced with a MOSFET; however, if cost savings are desired, a transistor can be used here.

[0026] This LED driver circuit can control the LED array by simultaneously controlling the positive and negative of the LEDs. It can also switch the actual voltage supplying the LEDs to isolate it from the system voltage (V1). This allows it to handle large loads, and by separating the control and load components, it also increases the system's safety. Figure 2The A and B ends correspond to respectively Figure 1 The numbers A1~A8 and B1~B8 are listed in the diagram. It should also be noted that the positive and negative signals output by the MCU are opposite to the positive and negative signals of the LEDs (A and B).

[0027] In summary, the circuit for controlling the LED array in this embodiment addresses the problems of weak load capacity, excessive MCU pin resources, and poor safety due to the inability to isolate the system control voltage from the load power supply voltage in traditional LED control circuits. By using a shift register to achieve serial-to-parallel conversion, only a few SPI data lines are needed to control 8 LED signals, significantly reducing the MCU pin resource usage. At the same time, the dual-voltage architecture with isolation between the control voltage and the load power supply voltage allows the LED driver circuit to independently provide 5V, 7V, or higher voltages. The driving capability is not limited by the system control voltage, enabling it to drive high-power LED arrays. Furthermore, the control section is electrically isolated from the load section, effectively improving system safety and stability. It also has the advantages of simple circuit structure, low cost, and strong scalability.

[0028] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A circuit for controlling an LED lamp array, characterized in that, include: MCU control unit; A shift register, connected to the MCU control unit, is used to receive serial control signals and convert them into parallel control signals, the parallel control signals including a first control signal and a second control signal; The LED light matrix includes multiple rows of positive control lines and multiple columns of negative control lines. The positive ends of each row of LEDs are connected to the corresponding positive control line, and the negative ends of each column of LEDs are connected to the corresponding negative control line. An LED driving circuit is connected between the shift register and the LED matrix. The LED driving circuit includes a control voltage terminal and a load power supply voltage terminal, which are used to provide the control voltage and the load power supply voltage isolated from the control voltage, respectively. The circuit converts the first control signal and the second control signal into driving signals, which are used on the positive control line and the negative control line, respectively, to selectively light up the LEDs in the matrix.

2. The circuit for controlling the LED lamp array as described in claim 1, characterized in that, The LED driving circuit includes: The first input terminal is used to receive the second control signal; The second input terminal is used to receive the first control signal; The first switching transistor has its control terminal connected to the first input terminal and its output terminal connected to the control terminal of the second switching transistor. The second switching transistor is connected between the load supply voltage and the LED positive terminal control line, and operates in the cutoff region or saturation region. The third switch has its control terminal connected to the second input terminal and its output terminal connected to the LED negative terminal control line. The control voltage terminal is used to provide the control voltage. The load power supply voltage terminal is used to provide the load power supply voltage, which is isolated from the control voltage; The first and third switching transistors operate in the amplification region.

3. The circuit for controlling the LED lamp array as described in claim 1, characterized in that, The shift register is connected to the MCU control unit via an SPI interface.

4. The circuit for controlling an LED lamp array as described in claim 1, characterized in that, The LED light matrix is ​​an N×N matrix, where N is an integer greater than or equal to 2.

5. The circuit for controlling an LED lamp array as described in claim 2, characterized in that, The first switching transistor is a transistor Q1, whose base is connected to the control voltage, its collector is connected to the control terminal of the second switching transistor, and its emitter is connected to the first input terminal through the fifth resistor R5.

6. The circuit for controlling an LED lamp array as described in claim 2, characterized in that, The third switching transistor is a transistor Q3, whose base is connected to the second input terminal through the second resistor R3, its emitter is grounded through the fourth resistor R4, and its collector is connected to the negative terminal control line.

7. The circuit for controlling an LED lamp array as described in claim 2, characterized in that, The second switching transistor is a transistor Q2, whose base is connected to the output terminal of the first switching transistor, its emitter is connected to the load power supply voltage, and its collector is connected to the positive terminal control line.

8. The circuit for controlling an LED lamp array as described in claim 2, characterized in that, The second switch is a MOSFET.

9. The circuit for controlling an LED lamp array as described in claim 1, characterized in that, An LED and a current-limiting resistor R6 are connected in series between the positive control line and the negative control line.

10. The circuit for controlling an LED lamp array as described in claim 1, characterized in that, The first control signal is a high-level signal, the second control signal is a low-level signal, and after being converted by the LED driving circuit, the driving signal levels on the positive and negative control lines are reversed.

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