PWM expansion circuit

By expanding the processor's PWM signal port through a PWM expansion circuit, the problems of processor resource waste and dimming jitter are solved, achieving efficient LED bead control and smooth dimming effect, and reducing production costs.

CN223584379UActive Publication Date: 2025-11-21GUANGDONG YIRI TECH CO LTD
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Patent Information

Application Number
CN202423045103.8
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-12-11
Publication Date
2025-11-21
Estimated Expiration
2034-12-11

AI Technical Summary

Technical Problem

The limited number of PWM signal output ports of the processor cannot meet the control requirements of a large number of LED beads, resulting in resource waste and increased production costs. At the same time, the low grayscale adjustment of the timer leads to jitter and large brightness fluctuations during dimming.

Method used

The PWM expansion circuit is adopted, which is connected to the processor through the expander U2 to expand the PWM signal port. The switch control unit is electrically connected to the LED beads one by one to realize the PWM signal communication between the processor and each LED bead. Combined with the low gray smooth gradient function and the built-in PWM maximum duty cycle adjustment, smooth dimming and brightness adjustment are achieved.

Benefits of technology

It effectively expands the PWM signal port, saves processor resources, reduces production costs, and achieves a smooth gradient display effect and high brightness adjustment for the lamps, with a dimming grayscale level of 65,536.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model relates to a PWM expansion circuit which comprises a processor, at least one expander U2, a power supply, a switch module composed of a plurality of switch control units, and a light-emitting module composed of a plurality of LED lamp beads connected in series, the power supply is electrically connected with the switch module and the light-emitting module, the expander U2 is provided with a plurality of PWM signal ports, and the PWM signal ports are electrically connected with the processor. And the PWM signal port, the switch control unit and the LED lamp beads are electrically connected in sequence in a one-to-one correspondence manner, so that the processor realizes PWM signal communication with each LED lamp bead of the light-emitting module through the expander U2. The processor can control the plurality of expanders U2, and each expander U2 is correspondingly connected with the switch module and the light-emitting module, so that the expansion of PWM signal ports is realized, the processor can realize PWM signal communication with each LED lamp bead, the number of processors does not need to be increased to meet the PWM signal ports, the resource waste is effectively saved, and the production cost is reduced.
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Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LED lamp lighting, in particular to a PWM expansion circuit. BACKGROUND

[0002] The processor outputs PWM signals to the driving module to control the LED lamp bead module, if the number of LED lamp beads is enough, but the number of PWM signal output ports of the controller is limited, which cannot meet the corresponding control of the LED lamp beads, therefore, the number of PWM signal output ports is increased by increasing the processor, which leads to the waste of processor port resources and high product production cost and other defects. In addition, the conventional processor has low gray level number of timer adjustment, which leads to the jitter during dimming and large brightness adjustment fluctuation. SUMMARY

[0003] The present application provides a PWM expansion circuit to solve the above technical problems, which can meet the number of PWM signal output ports to achieve the purpose of PWM signal control of numerous LED lamp beads.

[0004] To solve the above technical problems, the present application provides the following technical solutions:

[0005] A PWM expansion circuit, comprising a processor, at least one expander U2, a power supply, a switch module composed of a plurality of switch control units, and a light-emitting module composed of a plurality of LED lamp beads connected in series, wherein the power supply is electrically connected with the switch module and the light-emitting module respectively, the expander U2 has a plurality of PWM signal ports, the PWM signal ports, the switch control units and the LED lamp beads are electrically connected one by one in sequence, so that the processor realizes PWM signal communication with each LED lamp bead of the light-emitting module through the expander U2.

[0006] As a preferred implementation, it is further limited that the power supply includes a power supply module and a constant current power supply module, the constant current power supply module includes a first controller U6, the pin 1 of the first controller U6 is connected with one end of the resistor R33, one end of the resistor R32 and the power supply module respectively, the pin 3 of the first controller U6 is connected with the other end of the resistor R33, the other end of the resistor R32 and one end of the light emitting module respectively, the pin 4 is connected with one end of the resistor R37, one end of the capacitor C36 and one end of the resistor R42 respectively, the other end of the resistor R37 is connected with the "V11" end, the other end of the capacitor C36 and the other end of the resistor R42 are grounded, the pin 6 of the first controller U6 is divided into two paths, one path is grounded, and the other path is connected with one end of the capacitors C32 and C34 in parallel, the other end of the capacitors C32 and C34 is connected with the pin 8 of the first controller U6 and the power supply module respectively, the pin 7 of the first controller U6 is connected with the gate G of the field effect transistor Q11 through the resistor R38, the source S of the field effect transistor Q11 is grounded, the drain D of the field effect transistor Q11 is connected with the pin 9 of the first controller U6 and one end of the inductor L6 respectively, the other end of the inductor L6 is connected with the other end of the light emitting module.

[0007] As a preferred implementation, it is further limited that the switch control unit includes a second controller U91, the pin 1 of the second controller U91 is connected with one end of the resistor R1 and one end of the resistor R2 respectively, the other end of the resistor R2 is grounded, the other end of the resistor R1 is connected with one PWM signal port of the expander U2 and the positive electrode of the diode D1 respectively, the negative electrode of the diode D1 is connected with the "V11" end, the pin 2 of the second controller U91 is grounded, the pin 3 of the second controller U91 is connected with the gate G of the field effect transistor Q1, the source S of the field effect transistor Q1 is connected with the positive electrode of one LED lamp bead, the pin 5 of the second controller U91 and one end of the capacitor C1 respectively, the drain D of the field effect transistor Q1 is connected with the negative electrode of the LED lamp bead and the other end of the capacitor C1 respectively.

[0008] As a preferred implementation, it is further limited that the light emitting module includes red LED lamp beads, green LED lamp beads, blue LED lamp beads and white LED lamp beads.

[0009] As a preferred implementation, it is further limited that the model of the processor is APM32F103RCT6.

[0010] As a preferred implementation, it is further limited that the model of the expander U2 is SM15016S.

[0011] As a preferred implementation, it is further limited that the model of the first controller U6 is VAS1254.

[0012] As a preferred embodiment, it is further limited that the model of the second controller U91 is VAS1700.

[0013] After the technical scheme is applied, the application has at least the following beneficial effects:

[0014] 1. The processor is in communication connection with the extender U2 of the head end, that is, it can be in communication connection with all the extenders U2, each extender U2 is connected with a switch module and a light-emitting module, so as to realize the expansion of the PWM signal port, enable the processor to realize PWM signal communication with each LED lamp bead, and need not increase the number of processors to meet the PWM signal port, thereby effectively saving resource waste and reducing production cost.

[0015] 2. The extender has a low-gray smooth gradient function, realizes more smooth lamp low-gray gradient display effect (the lightness gray scale can reach 65536 levels), and has a built-in PWM maximum duty ratio coefficient adjustment, so that the highest brightness of the lamp can be adjusted without changing the hardware scheme. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is one of the principle block diagrams of the expansion circuit;

[0017] Figure 2 is the second principle block diagram of the expansion circuit;

[0018] Figure 3 is the circuit diagram of the extender U2;

[0019] Figure 4 is the circuit diagram of the power supply for one light-emitting module;

[0020] Figure 5 is the circuit diagram of the switch control unit;

[0021] Figure 6 is the circuit diagram of one light-emitting module;

[0022] Figure 7 is the circuit diagram of the connection of two extenders U2;

[0023] Figure 8 is the circuit diagram of the power supply for two light-emitting modules;

[0024] Figure 9 is the circuit diagram of the connection of two light-emitting modules. DETAILED DESCRIPTION

[0025] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict, and the present application will be further described in detail in combination with the drawings and specific embodiments.

[0026] As shown in the accompanying Figure 1As shown, a PWM expansion circuit, which can be applied to pixel lamps and other types of lamps, specifically includes a processor, at least one expander U2, a power supply, a switch module composed of a plurality of switch control units, and a light-emitting module composed of a plurality of LED lamp beads connected in series. The model of the processor is APM32F103RCT6. The power supply is electrically connected with the switch module and the light-emitting module, respectively. The expander U2 has a plurality of PWM signal ports. The PWM signal ports, the switch control units, and the LED lamp beads are electrically connected in sequence one by one, so that the processor realizes PWM signal communication with each LED lamp bead of the light-emitting module through the expander U2. The model of the expander U2 is SM15016S. The expander U2 can be provided with one or more according to requirements. A plurality of expanders U2 are connected in sequence, as shown in Figure 3 and Figure 7 As shown. The processor is in communication connection with the expander U2 of the head end, that is, it can complete communication connection with all expanders U2. Each expander U2 is connected with the switch module and the light-emitting module, so as to realize the expansion of the PWM signal port and enable the processor to realize PWM signal communication with each LED lamp bead, without the need to increase the number of processors to meet the PWM signal port, effectively saving resource waste and reducing production cost.

[0027] As shown in Figure 2 Further explanation, the expander U2 is provided with i, the switch module includes j switch control units, and the light-emitting module includes k LED lamp beads connected in series, wherein i, j and k are greater than or equal to 1 and are positive integers. For example, the first expander U2 can be connected with j switch control units and k LED lamp beads. The maximum value of j is determined by the number of PWM signal ports of the expander U2. In this embodiment, the expander U2 has 16 PWM signal ports, that is, the processor can realize PWM signal communication with 16 LED lamp beads through one expander U2, so as to achieve the purpose of dimming a large number of LED lamp beads.

[0028] As shown in Figure 1 and Figure 4As shown, the power supply includes a power supply module and a constant current power supply module, the constant current power supply module includes a first controller U6, the model of the first controller U6 is VAS1254. The pin 1 of the first controller U6 is connected with one end of the resistor R33, one end of the resistor R32 and the power supply module respectively, the pin 3 of the first controller U6 is connected with the other end of the resistor R33, the other end of the resistor R32 and one end of the light emitting module respectively, the pin 4 is connected with one end of the resistor R37, one end of the capacitor C36 and one end of the resistor R42 respectively, the other end of the resistor R37 is connected with the "V11" end, the other end of the capacitor C36 and the other end of the resistor R42 are grounded, the pin 6 of the first controller U6 is divided into two paths, one path is grounded, the other path is connected with one end of the capacitors C32 and C34 in parallel, the other end of the capacitors C32 and C34 is connected with the pin 8 of the first controller U6 and the power supply module respectively, the power supply module includes a +36V end and capacitors C25, C33 and C44 connected in parallel. The pin 7 of the first controller U6 is connected with the gate G of the field effect transistor Q11 through the resistor R38, the source S of the field effect transistor Q11 is grounded, the drain D of the field effect transistor Q11 is connected with the pin 9 of the first controller U6 and one end of the inductor L6 respectively, the other end of the inductor L6 is connected with the other end of the light emitting module, as shown in the attached Figure 4 and the attached Figure 6 As shown, a group of the light emitting modules includes four LED lamp beads connected in series, one end of which is connected with the "R21+" end, and the other end is connected with the "R21-" end. As shown in the attached Figure 8 and the attached Figure 9 As shown, two groups of the light emitting modules include eight LED lamp beads connected in series, one end of which is connected with the "R21+" end, and the other end is connected with the "R22-" end, so as to realize driving light emission of multiple groups of light emitting modules.

[0029] As shown in the attached Figure 5 The switch control unit includes a second controller U91, the model of the second controller U91 is VAS1700. The pin 1 of the second controller U91 is connected with one end of the resistor R1 and one end of the resistor R2 respectively, the other end of the resistor R2 is grounded, the other end of the resistor R1 ("R21" end) is connected with one PWM signal port of the expander U2 and the anode of the diode D1 respectively, the cathode of the diode D1 is connected with the "V11" end through the end, the pin 2 of the second controller U91 is grounded, the pin 3 of the second controller U91 is connected with the gate G of the field effect transistor Q1, the source S of the field effect transistor Q1 is connected with the anode of one LED lamp bead, the pin 5 of the second controller U91 and one end of the capacitor C1 respectively, the drain D of the field effect transistor Q1 is connected with the cathode of the LED lamp bead and the other end of the capacitor C1 respectively. Specifically, one switch control unit corresponds to control one LED lamp bead,

[0030] As shown in the accompanying drawings Figure 7 and the accompanying drawings Figure 9 The light-emitting module includes red LED lamp beads, green LED lamp beads, blue LED lamp beads and white LED lamp beads.

[0031] Specific working principle: the "PWM0" signal port of the expander U2 sends PWM signals to the switch control unit and the constant current power supply module through the "R21" end respectively, when sending high level, the pin 4 of the first controller U6 receives high level, and controls the constant current power supply module to turn on to supply power for the light-emitting module; at the same time, the pin 1 of the second controller U91 receives high level, at this time, the field effect tube Q1 is cut off (that is, the "R21+" end and the "R21-" end are disconnected), so that the LED lamp beads connected in parallel with the switch control unit are open circuit, and the brightness of the LED lamp beads can be adjusted.

[0032] When the "PWM0" signal port of the expander U2 sends low level, the pin 4 of the first controller U6 still maintains high level, the constant current power supply module remains to be turned on, and continues to supply power for the light-emitting module; at the same time, the pin 1 of the second controller U91 receives low level, at this time, the field effect tube Q1 is turned on (that is, the "R21+" end and the "R21-" end are connected), so that the LED lamp beads connected in parallel with the switch control unit are short-circuited, and the LED lamp beads are turned off.

[0033] Similarly, other signal ports of the expander U2 can also realize the above-mentioned control on other LED lamp beads.

[0034] The expander U2 of the present application not only can expand the PWM signal port, but also has the low gray smooth gradient function, realizes that the lamp low gray gradient display effect is more smooth (the gray scale of the light modulation can reach 65536 levels), and the built-in PWM maximum duty ratio coefficient adjustment is not necessary to change the hardware scheme, and the highest brightness of the lamp can be adjusted.

[0035] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various equivalent changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalent ranges.

Claims

1. A PWM extension circuit, characterized in that, The device includes a processor, at least one extender U2, a power supply, a switching module consisting of several switch control units, and a light-emitting module consisting of several LED beads connected in series. The power supply is electrically connected to the switching module and the light-emitting module respectively. The extender U2 has several PWM signal ports. The PWM signal ports, the switch control units, and the LED beads are electrically connected in sequence to each other, so that the processor can communicate with each LED bead of the light-emitting module through the extender U2 to achieve PWM signal communication.

2. The PWM extension circuit according to claim 1, characterized in that, The power supply includes a power supply module and a constant current power supply module. The constant current power supply module includes a first controller U6. Pin 1 of the first controller U6 is connected to one end of resistor R33, one end of resistor R32, and the power supply module, respectively. Pin 3 of the first controller U6 is connected to the other end of resistor R33, the other end of resistor R32, and one end of the light-emitting module, respectively. Pin 4 is connected to one end of resistor R37, one end of capacitor C36, and one end of resistor R42, respectively. The other end of resistor R37 is connected to the "V11" terminal, and the other end of capacitor C36 is connected to resistor R42. The other end is grounded. Pin 6 of the first controller U6 is divided into two paths: one is grounded, and the other is connected to one end of capacitors C32 and C34 in parallel. The other end of capacitors C32 and C34 in parallel is connected to pin 8 of the first controller U6 and the power supply module, respectively. Pin 7 of the first controller U6 is connected to the gate G of the field-effect transistor Q11 through resistor R38. The source S of the field-effect transistor Q11 is grounded. The drain D of the field-effect transistor Q11 is connected to pin 9 of the first controller U6 and one end of inductor L6, respectively. The other end of inductor L6 is connected to the other end of the light-emitting module.

3. The PWM extension circuit according to claim 2, characterized in that, The switch control unit includes a second controller U91. Pin 1 of the second controller U91 is connected to one end of resistor R1 and one end of resistor R2, respectively. The other end of resistor R2 is grounded. The other end of resistor R1 is connected to one of the PWM signal ports of the extender U2 and the positive terminal of diode D1, respectively. The negative terminal of diode D1 is connected to the "V11" terminal. Pin 2 of the second controller U91 is grounded. Pin 3 of the second controller U91 is connected to the gate G of the field-effect transistor Q1. The source S of the field-effect transistor Q1 is connected to the positive terminal of one of its LED beads, pin 5 of the second controller U91, and one end of capacitor C1, respectively. The drain D of the field-effect transistor Q1 is connected to the negative terminal of the LED bead and the other end of capacitor C1, respectively.

4. The PWM extension circuit according to claim 1, characterized in that, The light-emitting module includes red LED beads, green LED beads, blue LED beads and white LED beads.

5. The PWM extension circuit according to claim 1, characterized in that, The processor model is APM32F103RCT6.

6. The PWM extension circuit according to claim 1, characterized in that, The expander U2 is model number SM15016S.

7. The PWM extension circuit according to claim 2, characterized in that, The first controller, U6, is model VAS1254.

8. The PWM extension circuit according to claim 3, characterized in that, The second controller U91 is model VAS1700.