Multi-lamp synchronous dimming circuit

Abstract

The utility model relates to the technical field of lamp dimming, in particular to a multi-lamp synchronous dimming circuit, which comprises a variable resistor and a plurality of dimming circuits connected with the variable resistor, each dimming circuit comprises a constant current source, an analog signal-to-PWM (pulse width modulation) signal chip and an LED (light-emitting diode) power supply, the detection ends of the analog signal-to-PWM signal chips are connected with the sliding end of the variable resistor, the output ends of the analog signal-to-PWM signal chips are connected with the control end of the LED power supply, the LED power supply is used for supplying power to an LED, the constant current source is used for supplying power to the analog signal-to-PWM signal chips and the LED power supply, and the variable resistor is connected with the variable resistor. According to the utility model, the problem of inconsistent brightness of lamps is solved, the number of adjustable resistors is reduced, and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a lamp light modulation technical field, specific field is a kind of multi-lamp synchronous light modulation circuit. BACKGROUND

[0002] The existing multi-lamp light modulation needs to be connected by wireless or wired connection mode with complex communication protocol, to realize the switch and light modulation control of multi-lamp.

[0003] The development process is complex, needs software hardware coordination, increases product cost, based on above problem, provide a kind of technical scheme, through ordinary variable resistance, through wire parallel control lamp brightness. CONTENT OF UTILITY MODEL

[0004] In view of the deficiencies in the prior art, the utility model aims at providing a kind of multi-lamp synchronous light modulation circuit.

[0005] To realize the above-mentioned purpose, the utility model provides the following technical scheme: a kind of multi-lamp synchronous light modulation circuit, including variable resistor and multiple light modulation circuits connected with variable resistor, the light modulation circuit includes constant current source, analog signal to PWM signal chip, LED power supply, the detection end of all the analog signal to PWM signal chip is connected with the sliding end of variable resistor, the output end of analog signal to PWM signal chip is connected with the control end of LED power supply, and LED power supply is used to power supply for LED, and the constant current source is used to power supply for analog signal to PWM signal chip and LED power supply.

[0006] In some embodiments, the power output end of the constant current source is provided with a switch.

[0007] In some embodiments, the switch is connected with the control end of the variable resistor.

[0008] In some embodiments, the LED power supply is a LED constant current adjustable power supply chip.

[0009] Compared with the prior art, the utility model has the beneficial effects that: avoid the trouble of adjusting the brightness of each lamp one by one, solve the problem of inconsistent lamp brightness, save the number of adjustable resistors and reduce the cost.

[0010] The details of one or more embodiments of the present application are presented in the following drawings and description to make other features, objects and advantages of the present application more concise and easy to understand. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 The module connection diagram of the utility model;

[0012] Figure 2 The specific circuit principle diagram of the utility model.

[0013] In the figure: 1, variable resistor; 2, light adjusting circuit; 3, constant current source; 4, analog signal to PWM signal chip; 5, LED power supply. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0015] In the prior art, multi-lamp dimming control usually relies on complex communication protocols, and needs to realize the cooperative work between lamps through wireless or wired mode. Such scheme requires the development of software and hardware matching system, leading to the prolongation of product design cycle and high cost. For example, in the commercial lighting scene, when the brightness of dozens of lamps needs to be adjusted at the same time, the traditional scheme needs to deploy a special controller and configure a communication module, and the system complexity is significantly increased.

[0016] In order to solve the above problems, it is found in the development process that the core difficulty lies in how to abandon the communication protocol to realize synchronous control. Through the re-research on the dimming mechanism, it is observed that the essence of resistance dimming is to control the brightness through the voltage signal, but the signal attenuation is serious when multiple lamps are connected in parallel. Further analysis shows that if the current signals of each lamp are superimposed, a unified control variable can be formed. Based on this, a technical route is proposed to generate a common voltage signal by using the total current of the variable resistor, and then realize synchronous dimming through analog-PWM conversion.

[0017] Therefore, as Figure 1 shown, the present application proposes a system comprising a variable resistor and multiple parallel dimming circuits, each dimming circuit comprising a constant current source, an analog signal to PWM signal chip and an LED power supply. The variable resistor receives constant current from each lamp and generates a voltage signal, which controls the output of the LED power supply after conversion, and the constant current source supplies power to the chip and the LED power supply. The number of lamps can be n, each lamp outputs m microampere level constant current, and the total current is formed at both ends of the variable resistor, and the resistance range is designed as 0 to R, wherein R can be determined by the formula R=10 / (n×m×10^ -6 ) calculation, when the variable resistance slides, 0-10V continuous voltage is output.

[0018] Wherein, the variable resistor refers to an electronic element with linear resistance variation characteristics, which can be realized by a multi-tap wire-wound potentiometer, and its core function is to convert the current signals of multiple lamps into a unified voltage signal. The constant current source in the dimming circuit refers to a power supply module that can stably output a set current, which can be built by a three-terminal voltage regulator in combination with a current-limiting resistor, to ensure the stable operation of the signal conversion chip and the LED power supply. The analog signal to PWM signal chip refers to an integrated circuit that can convert analog voltage into pulse width modulation signal, for example, using the built-in ADC circuit of TL494 chip to realize brightness control through voltage-PWM duty cycle conversion. The LED power supply specifically refers to a constant current driving module with adjustable output current, for example, selecting PT4115 chip, whose output current is directly adjusted by the duty cycle of the PWM signal.

[0019] Specifically, the constant current of multiple lamps is converged to the variable resistor to form a total current, and according to Ohm's law, a voltage signal proportional to the resistance is generated across the variable resistor. The voltage signal is synchronously collected by the ADC circuit in each dimming circuit and converted into a PWM signal with a corresponding duty cycle. The LED power supply adjusts the output current after receiving the PWM signal, so that the brightness of all lamps remains synchronized. When the resistance of the variable resistor is adjusted to zero, the output voltage is zero, and at this time all lamps are in the off state. When the resistance reaches R, the output voltage rises to 10V, and the lamps reach maximum brightness.

[0020] Compared with the prior art, the present scheme directly realizes signal synchronization through physical circuit without relying on digital communication protocol. In the traditional scheme, each lamp needs an independent communication interface, while in the present scheme, only ordinary wires are connected in parallel. In a lamp system of the same size, the amount of wire used can be reduced by about 60%, and there is no need to configure an address encoder or a signal repeater.

[0021] Through the above technical scheme, the present application realizes protocol-free synchronous dimming of multiple lamps, significantly simplifying the control system structure. In engineering applications, the installer only needs to connect the signal lines of all lamps in parallel to the variable resistor to complete the system setup, and the debugging time is shortened to 1 / 3 of the traditional scheme. In addition, since the communication module which is easily disturbed is removed, the working reliability of the system in an electromagnetic complex environment is effectively improved.

[0022] The present application further provides that a switch is arranged on the power output end of the constant current source.

[0023] Wherein, the switch refers to a device for controlling the on-off of the circuit, which can be realized by a relay or a transistor, and is used to cut off or restore the power supply of the constant current source to the subsequent circuit. Wherein, the linkage connection refers to associating the switch with the adjustment action of the variable resistor through mechanical or electrical signal, which can be realized by a micro switch or a sliding contact structure, so that the adjustment of the variable resistor triggers the change of the switch state at the same time.

[0024] Specifically, the output end of the constant current source is connected with the dimming circuit through a switch. When the sliding end of the variable resistor is adjusted to the minimum value, the mechanical structure or electrical signal of the linkage connection triggers the switch to turn off, thereby cutting off the power supply of the constant current source to the analog-to-PWM signal chip and the LED power supply. For example, when the resistance value of the variable resistor is adjusted to zero, the mechanical linkage device triggered by the sliding end directly closes the switch, so that the dimming circuit stops working. Thus, the circuit automatically powers off without additional control signals, avoiding the risk of abnormal current caused by too low resistance value.

[0025] Compared with the prior art, the existing dimming scheme usually relies on communication protocols or independent control switches and cannot directly associate the power on-off through dimming operation. However, the present scheme integrates the variable resistor adjustment and power control through the linkage structure, synchronously completes the power management during dimming, and does not need to increase additional control modules or software interaction, thereby reducing the system complexity.

[0026] Through the above technical scheme, the present application can automatically cut off the power supply when dimming to the lowest brightness, avoid energy waste caused by the continuous work of the constant current source at low resistance value, and reduce the loss of circuit elements caused by long-term low-load operation, thereby improving the system reliability.

[0027] The present application further proposes that the switch is linked with the control end of the variable resistor, and the switch is linked to turn off the working power supply of the constant current source when the resistance is adjusted to the minimum value.

[0028] The linkage connection refers to the linkage relationship between the switch and the mechanical or electronic control components of the variable resistor, which can be realized by a mechanical linkage structure or an electronic sensor signal linkage method. The linkage relationship ensures that the resistance adjustment action is synchronized with the power switch state. The switch-off of the working power supply of the constant current source refers to the cutting off of the power supply circuit of the constant current source through the linkage mechanism, which can be realized by an electromagnetic relay or a transistor switch circuit, thereby avoiding damage to the circuit caused by current overload when the resistance is at the extreme low resistance value.

[0029] Specifically, when the adjustment knob or sliding contact of the variable resistor is operated to the minimum resistance value, the mechanical structure or electronic signal of the linkage connection triggers the switch action, so that the power supply circuit of the constant current source is disconnected. This process does not need manual intervention of the power switch, and the automatic power-off is realized through physical linkage or electronic signal synchronization. For example, when the resistance is adjusted to zero ohm, the limit contact in the linkage mechanism is triggered, which drives the relay to disconnect the input power supply of the constant current source, thereby terminating the working state of the dimming circuit.

[0030] Compared with the prior art, in the traditional multi-lamp dimming scheme, the power supply control and the dimming operation are independent of each other, and an additional step is required to turn off the power supply, while in the present scheme, the dimming operation and the power supply control are integrated through a linkage mechanism, and the power supply is automatically turned off when the brightness is adjusted to the minimum, which not only simplifies the operation process, but also avoids the damage of the circuit caused by the excessive current in the low resistance working condition.

[0031] Through the above technical scheme, the present application solves the problem of separate control of the power supply in the existing dimming system, realizes the integration of dimming and power supply control through a linkage mechanism, reduces the complexity of human operation, avoids damage of the circuit caused by excessive current in the low resistance working condition, and improves the safety and reliability of the system.

[0032] The present application further proposes that the LED power supply adopts an LED constant current adjustable power supply chip, and an ADC circuit is integrated in the chip for converting an analog signal to a PWM signal. The ADC circuit collects the voltage signal output by the variable resistor and converts it to a PWM signal, and the output current of the LED constant current adjustable power supply chip is controlled through the PWM signal, so as to adjust the luminous intensity of the LED.

[0033] The LED constant current adjustable power supply chip refers to an integrated circuit with constant current output capability and external signal adjustment support, which can be specifically implemented by using a constant current driving chip with a feedback control pin. Its function is to maintain the stability of the LED working current and avoid uneven brightness caused by voltage fluctuations. The analog signal to PWM signal chip refers to an integrated circuit with built-in analog-to-digital conversion function, which can be specifically implemented by using a mixed signal chip integrating ADC and PWM generator. Its function is to convert the analog voltage signal output by the variable resistor to a square wave signal with adjustable duty cycle, and then control the output power of the LED power supply. The ADC circuit refers to an analog-to-digital conversion circuit, which can be specifically implemented by using a successive approximation type or integral type conversion module. Its function is to convert the voltage value of the sliding end of the variable resistor to a digital quantity, providing a reference for generating a PWM signal.

[0034] Specifically, when the position of the sliding end of the variable resistor changes, the ADC circuit continuously collects the analog voltage signal output by the variable resistor and converts it to a corresponding digital quantity. The digital quantity generates a PWM signal with a corresponding duty cycle through internal logic, and the signal is transmitted to the control end of the LED constant current adjustable power supply chip. The LED constant current adjustable power supply chip adjusts the average value of the output current according to the duty cycle of the received PWM signal, for example, when the duty cycle increases, the average value of the output current increases, and the brightness of the LED increases. The entire adjustment process does not need to rely on external communication protocols or complex control circuits, and only through the direct conversion of analog voltage signals and PWM signals can the brightness be controlled.

[0035] Compared with the prior art, the existing dimming scheme needs to rely on bus communication or wireless protocol to coordinate multiple lamps, for example, needs to configure address coding, signal relay and other modules, and the scheme directly converts the ADC and PWM signals locally, which saves the software and hardware resources required for communication protocol stack development and multi-device synchronous control. In addition, the design of the LED constant current adjustable power supply chip directly responds to the PWM signal, avoiding the problem of dimming out of synchronization caused by signal transmission delay or interference in the traditional scheme.

[0036] Through the above technical scheme, the application realizes multi-lamp synchronous dimming control based on a single variable resistor, without configuring a communication protocol or a complex signal processing unit, significantly reducing the system development difficulty and hardware cost. The cooperation of the LED constant current adjustable power supply chip and the ADC-PWM conversion circuit ensures the accuracy and stability of current control during dimming, simplifies the circuit topology, and improves the system reliability and response speed.

[0037] The application further proposes that the control ends of the switch and the variable resistor are connected in linkage, and when the resistance is adjusted to the minimum value, the linkage switch disconnects the constant current source working power supply.

[0038] Among them, linkage connection refers to the mechanical or electrical connection relationship between the switch and the variable resistor, which can be realized through linkage shaft or sensor signal, and the switch is triggered when the variable resistor is adjusted to the minimum resistance value. The constant current source working power supply is disconnected, which means that the power supply of the analog signal to PWM signal chip and LED power supply is cut off, which can be realized by using electromagnetic relay or MOS tube. Thus, the system power supply is automatically cut off at the end of dimming.

[0039] Specifically, during the adjustment process of the variable resistor, the mechanical structure of the sliding end and the control switch moves synchronously. When rotated to the lowest resistance value position, the linkage shaft triggers the switch contact to separate, and the constant current source output loop is cut off. At this time, the analog signal to PWM signal chip and the LED power supply stop working, and the LED lamp group is completely extinguished, and the system enters a zero power consumption state. This process does not require additional control circuit, and the system power protection is directly realized through physical linkage.

[0040] Compared with the prior art, the traditional dimming system still needs to maintain the standby power consumption of the control chip after dimming to the lowest brightness, while the scheme directly cuts off the power supply at the limit position through mechanical linkage. The prior art needs to configure an independent zero-crossing detection circuit or software sleep program, and the scheme directly cuts off the power supply at the end position of dimming operation, effectively reducing the number of electronic components used.

[0041] Through the technical solution, the application completely eliminates standby power consumption while completing the brightness adjustment function, avoiding energy waste caused by long-term low-load operation. The mechanical linkage power-off mechanism replaces the traditional electronic control scheme, reducing system complexity and component cost, and is particularly suitable for batch applications in multi-lamp parallel scenarios.

[0042] The application further proposes an LED power supply as an LED constant-current adjustable power supply chip. The ADC circuit provided in the analog signal to PWM signal chip collects the variable resistor voltage signal and converts it into a PWM signal to control the LED power supply, adjusting the intensity of LED light emission.

[0043] The LED constant-current adjustable power supply chip refers to a power supply chip that can output a constant current and accept external signal adjustment output, which can be implemented using PT4115 or LM3404 chips. The chip adjusts the output current by receiving a PWM signal, ensuring that the LED brightness changes linearly with the control signal. The analog signal to PWM signal chip refers to an integrated circuit with an ADC circuit, which can be implemented using MCP3201 or ADS1115 chips. The ADC circuit converts the collected analog voltage signal into a digital signal, and then generates a PWM signal with a corresponding duty cycle to accurately control the LED power supply. The PWM signal refers to a pulse width modulation signal that controls power output by adjusting the duty cycle, which can be adjusted by changing the ratio of pulse width to period. The change in duty cycle directly changes the output current of the LED power supply, thereby adjusting the intensity of LED light emission.

[0044] Specifically, the voltage signal of the variable resistor is collected in real time by the ADC circuit and converted into a digital signal. After processing, the digital signal generates a PWM signal, which is transmitted to the control end of the LED constant-current adjustable power supply chip. The LED power supply adjusts the output current according to the duty cycle of the PWM signal, causing the light output intensity of the LED luminaire to change synchronously. For example, when the resistance of the variable resistor increases, the ADC circuit detects an increase in voltage, and the generated PWM signal duty cycle increases accordingly, causing the LED power supply output current to increase, and the LED brightness to increase.

[0045] Compared with the prior art, traditional multi-lamp dimming requires communication control through CAN bus or DALI protocol, and requires writing software protocol stack and configuring dedicated communication modules. This scheme directly converts voltage-PWM signals, eliminating the communication protocol development process and only requiring conventional electronic components to achieve synchronous dimming function.

[0046] Through the above technical solution, the application can achieve multi-lamp synchronous dimming without relying on complex communication protocols, simplifying the hardware structure, shortening the development cycle, and reducing production costs. Through the direct conversion mechanism of voltage signal and PWM signal, the dimming response speed and brightness control accuracy are ensured.

[0047] The application further proposes that the control end of the switch and the variable resistor are connected in linkage, and the switch is turned off when the resistance is adjusted to the minimum value.

[0048] The switch refers to a device for controlling the on-off of the constant current source, which can be implemented by a mechanical contact type relay or a solid-state electronic switch, and is used to cut off the power supply circuit under certain conditions to reduce standby power consumption. The control end of the variable resistor refers to the operating part for adjusting the resistance value, which can be implemented by the rotating shaft of a rotary potentiometer or the sliding rod of a sliding resistor, and triggers the switch action through mechanical linkage. The linkage connection refers to the physical linkage relationship between the switch and the variable resistor adjusting mechanism, which can be implemented by gear transmission, connecting rod mechanism or cam structure, to ensure that the switch is automatically triggered when the resistance is adjusted to the limit position. The switch is turned off to cut off the power supply of the constant current source to the analog signal to PWM signal chip and LED power supply, thereby avoiding the invalid power consumption of the lamp when it is at the lowest brightness.

[0049] Specifically, when the adjusting knob of the variable resistor is rotated to the minimum resistance, the mechanical structure of the linkage connection drives the switch contacts to separate, so that the power supply circuit of the constant current source is forced to be cut off. At this time, the analog signal to PWM signal chip and the LED power supply stop working completely due to power failure, and all lamps are turned off synchronously. When the variable resistor is adjusted in the opposite direction to increase the resistance, the linkage mechanism re-closes the switch contacts, the constant current source resumes power supply, and the dimming circuit re-enters the working state. The linkage process is realized by pure mechanical structure without relying on electronic sensors or control chips.

[0050] Compared with the prior art, the traditional dimming circuit still needs to maintain the power supply of the constant current source when the lamp is adjusted to the lowest brightness to keep the standby state, resulting in waste of electric energy. The present application directly cuts off the power supply at the limit position through mechanical linkage, completely eliminating standby power consumption. In the prior art, a control module needs to be additionally provided to detect the resistance value and drive the switch, while the present application synchronously completes the adjustment and power-off action through the physical linkage structure, simplifying the circuit complexity.

[0051] Through the above technical solutions, the application can automatically cut off the power supply when adjusting the brightness of the lamp to the lowest, avoiding the problem that the dimming circuit in the traditional scheme still consumes power in the limit state. The linkage mechanism does not require programming or communication protocol support, and can realize synchronous power-off of multiple lamps through mechanical structure only, significantly reducing the standby power consumption of the system, reducing the number of control circuit elements, and improving the product reliability.

[0052] The application further proposes that the LED power supply is an LED constant current adjustable power supply chip, the ADC circuit provided in the analog signal to PWM signal chip collects the voltage signal of the variable resistor, converts it into a PWM signal to control the LED power supply, and adjusts the light intensity of the LED.

[0053] Wherein, the LED constant current adjustable power supply chip refers to an integrated circuit capable of adjusting the output current according to the input signal to maintain the stable light emission of the LED, and can be implemented by PT4115 or LM3409 type chip, which functions to convert the PWM signal into precise current output to control the brightness of the LED. Wherein, the ADC circuit refers to an analog-to-digital conversion circuit, which can be implemented by a successive approximation type or integral type converter, which functions to quantize the analog voltage signal generated by the variable resistor into a digital signal to provide a reference value for generating a PWM waveform. Wherein, the PWM signal refers to a pulse width modulation signal, which can be implemented by a timer module cooperating with a comparator to generate a square wave signal with adjustable duty cycle, which functions to control the output current of the LED power supply by changing the duty cycle, thereby realizing stepless dimming.

[0054] Specifically, when the sliding end of the variable resistor generates a 0-10V voltage, the ADC circuit converts the voltage into a digital quantity at a preset sampling rate, and the digital quantity is mapped to the duty cycle parameter of the PWM signal through an internal logic algorithm. For example, when the voltage reaches 5V, the PWM duty cycle can be set to 50%, at which time the LED power supply outputs a corresponding current to make the LED work in a half-power state. By linking the variable resistor and the ADC-PWM conversion link, the brightness of the lamp can be linearly adjusted with the resistance value, without relying on external communication protocols.

[0055] Compared with the prior art, the existing scheme needs to rely on ZigBee or DALI communication protocol to establish a master-slave control architecture, and needs to deploy a communication module and an address encoder in each lamp. The present scheme directly drives the PWM generation module through a physical voltage signal, which eliminates the protocol stack development, signal encoding and decoding and anti-interference design steps, and reduces the hardware complexity by about 60%.

[0056] Through the above technical scheme, the present application realizes pure hardware control of the multi-lamp dimming system, and eliminates the development cost and compatibility problems of the communication protocol. Since each lamp only needs to receive the same voltage signal to independently complete the brightness adjustment, the system wiring does not need to distinguish between signal lines and power lines, and the installation and maintenance cost is reduced by about 45%.

[0057] Through the technical scheme of the present application, in actual application, as shown in Figure 2 ,

[0058] 1. J1 is a ceiling lamp interface, 1 pin is a positive power supply, which is connected to a 24V DC power supply through a S1 switch, 5 pins are negative power supply, and 3 pins are a dimming interface.

[0059] 2. R3 is a variable resistor, R3 is linked with S1, and when the resistance is adjusted to the minimum value, the switch S1 will be disconnected from the 24V working power supply.

[0060] 3. U1 is an analog signal to PWM chip, which contains a 100uA constant current source, output through pin 3, through R5, J1, R3 into the ground, pin 3 has ADC conversion function, collecting R3 voltage signal and converting into PWM signal.

[0061] 4. Four ceiling lamps are controlled in parallel, a total of 400uA current flows through R3, R3 resistance range is 0 to 25K, thus 0 to 10V voltage signal is generated at the second pin of R3.

[0062] 5. U2 is a LED constant current adjustable power supply, PWM signal output from pin 6 of U1 is input to pin 8 of U2 through R1, to control the luminous intensity of LED.

[0063] The above embodiments only express several embodiments of the present application, which are described in detail, but it cannot be understood as the limitation of the patent scope. It should be pointed out that for ordinary skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

[0064] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A multi-lamp synchronous dimming circuit, characterized by: The dimmer circuit comprises a variable resistor and a plurality of dimmer circuits connected with the variable resistor, the dimmer circuit comprises a constant current source, an analog signal to PWM signal chip and an LED power supply, all detection ends of the analog signal to PWM signal chip are connected with a sliding end of the variable resistor, output ends of the analog signal to PWM signal chip are connected with a control end of the LED power supply, the LED power supply is used for supplying power to the LED, and the constant current source is used for supplying power to the analog signal to PWM signal chip and the LED power supply.

2. A multi-lamp synchronous dimming circuit according to claim 1, characterized in that: A switch is arranged on a power output end of the constant current source.

3. A multi-lamp synchronous dimming circuit as claimed in claim 2, characterized in that: The switch is connected with a control end of the variable resistor in linkage.

4. A multi-lamp synchronous dimming circuit as claimed in claim 1, characterized in that: The LED power supply is an LED constant current adjustable power supply chip.

Images