Stepless dimming circuit

Abstract

The utility model relates to the technical field of lighting lamps, aims to solve the technical problems of poor dimming effect, higher energy consumption and inconvenience in control in the traditional dimming mode, and discloses a stepless dimming circuit, which comprises a rectifier filter circuit and a step-down circuit, the step-down circuit is connected with a main control circuit used for adjusting the output state of the step-down circuit, the main control circuit is connected with a night lamp control circuit and a WIFI module, and the output end of the rectification filter circuit is connected with an auxiliary power supply used for supplying power to the main control circuit, the night lamp control circuit and the WIFI module; the main control circuit comprises a control module U6, the step-down circuit comprises a constant-current driving module U5 controlled by the control module U6, the current of the LED lamp is controlled through the constant-current driving module U5, stepless dimming is achieved, and the brightness of the lamp can be stably changed from the darkest to the brightest. By adjusting the brightness proportion of the LEDs with different colors on the LED lamp panel, the color adjusting function is achieved, and the lamp can present different color temperatures and color effects.

Description

Technical Field

[0001] The utility model relates to the technical field of lighting fixtures, in particular to a stepless dimming circuit. Background Art

[0002] The existing LED dimming technology has a way of dimming through a mechanical switch, but its circuit structure is relatively complex, resulting in high cost. In addition, it is large in size and not conducive to installation. To this end, the Chinese invention patent with publication number CN108289354A discloses a dimming circuit and a potentiometer, including a potentiometer, a resistor, a bidirectional thyristor, a bidirectional trigger diode and a capacitor; the potentiometer includes a resistor body and a tap, the tap is slidably connected to the resistor body, the tap is connected to the first end of the capacitor, the second end of the capacitor is used to connect to the second power input terminal through the load, the first end of the resistor body is used to connect to the first power input terminal through the resistor... The outer surface of the second end of the resistor body is provided with an insulating layer.

[0003] Although it is an improvement over the previous method, the current or voltage in the LED circuit is changed by adjusting the resistance of the potentiometer to adjust the brightness of the LED. However, the potentiometer dimming has problems such as large energy loss and unstable control. Utility Model Content

[0004] The utility model aims to provide a stepless dimming circuit to solve the technical problems of poor dimming effect, high energy consumption and inconvenient control in traditional dimming methods.

[0005] To achieve the above-mentioned purpose, the utility model provides a stepless dimming circuit, including a rectifier and filter circuit, a rear stage of the rectifier and filter circuit is provided with a step-down circuit for directly supplying power to a light board, the output end of the rectifier and filter circuit serves as the positive terminal for supplying power to the light board, the step-down circuit is connected to a main control circuit for adjusting the output state of the step-down circuit, the main control circuit is connected to a night light control circuit and a WIFI module, the output end of the rectifier and filter circuit is connected to an auxiliary power supply for supplying power to the main control circuit, the night light control circuit and the WIFI module; the main control circuit includes a control module U6, the step-down circuit includes a constant current drive module U5 controlled by the control module U6, the power input end of the constant current drive module U5 is connected to the output end of the rectifier and filter circuit through a current limiting resistor, and the output end of the constant current drive module U5 serves as the negative terminal for supplying power to the light board through an inductor L4.

[0006] Furthermore, the power input end of the constant current drive module U5 is grounded through capacitor C23; the open circuit protection voltage adjustment end of the constant current drive module U5 is grounded through a capacitor C22 and a resistor R55 connected in parallel; the PWM dimming input end of the constant current drive module U5 is connected to the control module U6 through a resistor R48; the output end of the constant current drive module U5 is connected to the output end of the rectifier and filter circuit through a diode D21, the cathode of the diode D21 is connected to the output end of the rectifier and filter circuit, the negative end is grounded through a capacitor C25, and a parallel power supply R52 and a capacitor C31 are arranged between the positive end and the negative end.

[0007] By connecting capacitor C22 and resistor R55 in parallel to ground, the open circuit protection voltage can be adjusted to protect the constant current drive module from damage when the circuit is open. The PWM dimming input is connected to the control module U6 through resistor R48 to adjust the brightness of the LED lamp and increase the flexibility and controllability of the lamp. The output of the constant current drive module U5 is connected to the output of the rectifier and filter circuit through diode D21 to power the LED lamp board. The setting of diode D21 can prevent reverse current and improve the stability and safety of the entire circuit.

[0008] This connection method enables the constant current drive module to play a beneficial role in the stepless dimming circuit, such as high stability, strong reliability, and good protection function, ensuring the stable, safe and efficient operation of the entire dimming circuit.

[0009] Furthermore, the current limiting resistor is composed of a resistor R57 and a resistor R58 connected in series, and the control module U6 is grounded through the resistor R51 and the buzzer BZ1 in sequence.

[0010] The current limiting resistor formed by the series resistor R57 and the resistor R58 can limit the current and play a role in current limiting protection to prevent the components in the circuit from being damaged by excessive current. The control module U6 is grounded through the resistor R51 and the buzzer BZ1 to achieve dimming control of the LED lamp. The buzzer BZ1 can be used as an indicator of dimming feedback.

[0011] Furthermore, the night light control circuit includes an NPN-type transistor Q16, the emitter of the transistor Q16 is grounded, the base of the transistor Q16 is connected to the control module U6 through a resistor R65, and a resistor R64 is connected between the base and emitter of the transistor Q16; the collector of the transistor Q16 is connected to the output end of the auxiliary power supply through a light-emitting diode D22 and a pull-up resistor in sequence, the pull-up resistor is also connected to a switch SW3, and the switch SW3 is provided with a left terminal, a right terminal and a middle terminal, the left terminal is grounded, the right terminal is connected to the output end of the auxiliary power supply, and the middle terminal is connected to the control module U6.

[0012] The night light function is realized by controlling the NPN transistor Q16. When the ambient brightness is low, the control module U6 can control the transistor Q16 to conduct through the resistor R65, so that the light-emitting diode D22 lights up and provides soft night lighting. The realization of the night light function can provide sufficient lighting at night, avoid the energy waste caused by using high-power lamps at night, save energy, and reduce energy consumption.

[0013] Furthermore, the front stage of the rectifier and filter circuit is also provided with an EMC circuit, which includes a varistor, an X capacitor C27, a resistor R53 and a resistor R54 arranged between the live wire L and the neutral wire N, and the two ends of the varistor and the X capacitor C27 are respectively connected to the live wire L and the neutral wire L; the resistor R53 and the resistor R54 are connected in series, and after the series connection, they are respectively connected to the live wire L and the neutral wire L; a primary common mode inductor T1 and a secondary common mode inductor T2 are also provided, which are connected to the rectifier and filter circuit after passing through the secondary common mode inductor T2.

[0014] The EMC circuit can effectively suppress electromagnetic interference in the circuit by setting components such as varistors, X capacitors and common-mode inductors, ensuring that the circuit does not interfere with the external environment when working, while also improving the circuit's own anti-interference ability.

[0015] The setting of varistor and X capacitor can play a protective role when overvoltage occurs in the circuit, protecting other components from damage. The primary and secondary common mode inductors T1 and T2 can filter the common mode interference, improve the stability and reliability of the circuit, and ensure the normal operation of the LED lamp.

[0016] This connection method enables the entire EMC circuit to suppress interference, protect circuits and lamps, and improve stability in the stepless dimming circuit, ensuring the normal operation of LED lamps and meeting the requirements of electromagnetic compatibility.

[0017] Furthermore, the main control circuit is also connected to a mains power detection circuit.

[0018] The mains detection circuit can monitor the mains power supply status. When the mains power supply is abnormal (such as power outage), the LED lamp can be stopped in time to reduce the use of batteries. The mains detection circuit can control the working state of the LED lamp according to the mains power supply status.

[0019] The stepless dimming circuit provided by the utility model has the following advantages:

[0020] First, the current of the LED lamp is controlled by the constant current drive module U5, which realizes stepless dimming, so that the brightness of the lamp can be smoothly adjusted from the darkest to the brightest, providing a more comfortable and soft light environment. Secondly, by adjusting the brightness ratio of different color LEDs on the LED light board, the color adjustment function is realized, so that the lamp can present different color temperatures and color effects to meet the lighting needs in different scenes. In addition, the night light control circuit and WIFI module connected to the main control circuit enable the lamp to have a night light function and intelligent control capabilities. The night light function can automatically adjust the brightness of the lamp according to the ambient brightness to provide soft night lighting. In general, the design of this stepless dimming circuit improves the dimming effect and comfort of the lamp, saves energy, prolongs the service life of the LED lamp, and also improves the practicality and ornamental value of the lamp. The design of this stepless dimming circuit not only realizes the functions of stepless dimming, color adjustment and brightness adjustment, but also brings many other beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a functional block diagram of the stepless dimming circuit provided by the utility model;

[0022] Figure 2 The rectifier filter circuit and the step-down circuit diagram provided by the utility model;

[0023] Figure 3 The main control circuit diagram provided by the utility model;

[0024] Figure 4 The night light control circuit diagram provided by the utility model;

[0025] Figure 5 This is the EMC circuit diagram provided by the utility model. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0027] See also Figure 1 The utility model provides a stepless dimming circuit, including a rectifier and filter circuit, a step-down circuit connected to a lamp board is arranged at the rear stage of the rectifier and filter circuit, the step-down circuit is connected to a control module, the output end of the rectifier and filter circuit serves as a positive terminal for supplying power to the lamp board, and an EMC circuit is arranged at the front stage of the rectifier and filter circuit.

[0028] See also Figure 2The rectifier and filter circuit includes a bridge full-wave rectifier module composed of a diode D17, a diode D18, a diode D19 and a diode D20. The bridge full-wave rectifier module outputs a DC power supply and then filters it through a capacitor C26.

[0029] At least one step-down circuit is provided, and the step-down circuit includes a constant current drive module U5. The first end of the constant current drive module U5 is a power input end, which is connected to the output end of the rectifier filter circuit through two series-connected resistors R57 and R58, and is grounded through a capacitor C23; the second end of the constant current drive module U5 is an open circuit protection voltage adjustment end, which is grounded through a capacitor C22 and a resistor R55, and the capacitor C22 and the resistor R55 are connected in parallel; the third end of the constant current drive module U5 is a PWM dimming input end, which is connected to the output end of the rectifier filter circuit through a resistor R48. The control module is connected; the 4th terminal of the constant current drive module U5 is grounded; the 5th and 6th terminals of the constant current drive module U5 are internal power tube drain terminals, which are connected to the output terminal of the rectifier and filter circuit through a diode D21, the anode of the diode D21 is connected to the 5th terminal of the constant current drive module U5, the cathode of the diode D21 is connected to the output terminal of the rectifier and filter circuit, and the inductor L4 is used as the negative terminal for supplying power to the lamp board, the negative terminal is grounded through a capacitor C25, and a power supply R52 and a capacitor C31 are connected between the positive terminal and the negative terminal.

[0030] The rectifier and filter circuit converts AC power into DC power and smoothes the voltage; the step-down circuit reduces the high voltage output by the rectifier and filter circuit to the low voltage required by the lamp board, and the constant current drive module controls and adjusts the output current; the control module outputs a PWM dimming signal to the constant current drive module U5 to realize the stepless dimming function of the LED lamp.

[0031] Working principle: When the circuit is powered on, the rectifier and filter circuit converts AC power into DC power, and reduces the voltage to the voltage required by the LED lamp through the step-down circuit. The output current is controlled by the constant current drive module, and the brightness of the LED lamp is adjusted through the PWM dimming signal. The entire circuit realizes the stepless dimming function of the LED lamp.

[0032] PWM (Pulse Width Modulation) dimming controls the brightness of the LED by controlling the width of the pulse in each dimming cycle. The larger the pulse width, the longer the LED is powered on and the higher the brightness; the smaller the pulse width, the shorter the LED is powered on and the lower the brightness. Due to the visual characteristics of the human eye, even if the pulse frequency is high, the LED will be perceived as a stable brightness during the rapid switching process. By adjusting the width of the PWM pulse, the stepless dimming effect of the LED lamp can be achieved.

[0033] In one embodiment of the present invention, two step-down circuits are provided, which respectively output different voltages to two groups of light panels, so as to adjust the color temperature.

[0034] exist Figure 3 In the embodiment, the main control circuit includes a control module U6, and the control module U6 is connected to a buzzer BZ1 via a resistor R51.

[0035] See also Figure 4 A night light control circuit is provided, including an NPN transistor Q16, the emitter of the transistor Q16 is grounded, the base of the transistor Q16 is connected to the control module U6 through a resistor R65, and a resistor R64 is connected between the base and emitter of the transistor Q16.

[0036] The collector of transistor Q16 is connected to the output end of the auxiliary power supply through light-emitting diode D22 and pull-up resistor in sequence. Specifically, the cathode of light-emitting diode D22 is connected to the collector of transistor Q16, and the anode of light-emitting diode D22 is connected to the pull-up resistor, which includes two parallel resistors R66 and R77. The pull-up resistor is also connected to switch SW3, which is provided with three terminals, the terminals on both sides are respectively grounded and connected to the output end of the auxiliary power supply, and the middle terminal of switch SW3 is connected to control module U6. Switch SW3 is provided with a paddle, which can connect the middle terminal to the left terminal or the right terminal when it is turned to set different working modes.

[0037] The control module U1 can generate a pulse signal to the base of the transistor Q16 to control the conduction state of the transistor Q16, so that the light emitting diode D22 can be turned on and off.

[0038] exist Figure 1 In the circuit, the auxiliary power supply is used to generate a 3.3V voltage for the night light control circuit, the main control circuit and the WIFI module. The auxiliary power supply specifically includes the first step-down module and the second step-down module. If the voltage is directly stepped down in the first stage, the voltage difference is large and the current is large, resulting in large losses of components such as diodes and capacitors and low efficiency. The voltage difference of each stage can be reduced through the second step-down module to improve the overall efficiency. In addition, the second step-down module can generate a linear power supply with smaller ripple to ensure the stability of the subsequent circuit.

[0039] The WIFI module can be set up to control it through wireless remote control, and stepless dimming, color adjustment and brightness adjustment can be achieved through key addition and subtraction. For example, short press the gear position for segmented dimming and color adjustment, long press for stepless dimming and color adjustment, and the color changes slowly and evenly. During the adjustment process, the buzzer BZ1 responds to the feedback status.

[0040] See also Figure 5The EMC circuit includes a fuse F1 connected in series to the live wire L, a varistor, an X capacitor C27, a resistor R53 and a resistor R54 are arranged between the live wire L and the neutral wire N, and the two ends of the varistor and the X capacitor C27 are connected to the live wire L and the neutral wire L respectively; the resistor R53 and the resistor R54 are connected in series, and after the series connection, they are connected to the live wire L and the neutral wire L respectively; the X capacitor C27 is used to suppress differential mode interference, and a primary common mode inductor T1 and a secondary common mode inductor T2 are also arranged. The AC power is finally connected to the rectifier and filter circuit after passing through the secondary common mode inductor T2.

[0041] Fuse F1 is used to provide overload protection in the circuit. When the current in the circuit exceeds the rated value, the fuse will blow, cutting off the circuit and preventing damage to the equipment.

[0042] Varistors are used to suppress overvoltage in circuits. When the voltage exceeds the set value, the varistor will become a high-resistance state, consume the overvoltage, and protect other components in the circuit.

[0043] X capacitor C27 is used to suppress differential mode interference, that is, interference between two leads in the circuit. X capacitor is a capacitor specially used for power lines, which can effectively filter out high-frequency noise and interference on the power lines.

[0044] Resistor R53 and resistor R54 have relatively large resistance values. These two resistors are connected in series. First, they can be used for filtering. Second, they can consume the current of inductive or capacitive devices when the city power is cut off, making the circuit safer.

[0045] Common mode inductors T1 and T2 are used to suppress common mode interference, that is, the interference between the leads in the circuit and the ground. Common mode inductors can filter out common mode signals to ensure the stability and reliability of the circuit.

[0046] The design of the entire circuit is intended to ensure that the circuit is less sensitive to electromagnetic interference from the external environment when working, while also ensuring that the circuit's own electromagnetic interference is small, in order to improve the electromagnetic compatibility of the equipment.

[0047] The stepless dimming circuit provided by the utility model has the following advantages:

[0048] By controlling the current of the LED lamp through the constant current drive module U5, stepless dimming is achieved, so that the brightness of the lamp can be smoothly adjusted from the darkest to the brightest, providing a more comfortable and soft lighting environment. By adjusting the brightness ratio of different color LEDs on the LED light board, the color adjustment function is realized, so that the lamp can present different color temperatures and color effects to meet the lighting needs in different scenes. In addition, the night light control circuit and WIFI module connected to the main control circuit enable the lamp to have a night light function and intelligent control capabilities. The night light function can automatically adjust the brightness of the lamp according to the ambient brightness to provide soft night lighting.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A stepless dimming circuit, comprising a rectifier and filter circuit, wherein a step-down circuit for directly supplying power to a light board is arranged at the rear stage of the rectifier and filter circuit, and the output end of the rectifier and filter circuit serves as a positive terminal for supplying power to the light board, characterized in that: The step-down circuit is connected to a main control circuit for adjusting the output state of the step-down circuit, the main control circuit is connected to a night light control circuit and a WIFI module, and the output end of the rectifier and filter circuit is connected to an auxiliary power supply for supplying power to the main control circuit, the night light control circuit and the WIFI module; the main control circuit includes a control module U6, and the step-down circuit includes a constant current drive module U5 controlled by the control module U6, the power input end of the constant current drive module U5 is connected to the output end of the rectifier and filter circuit through a current limiting resistor, and the output end of the constant current drive module U5 is used as the negative terminal for supplying power to the light board through an inductor L4.

2. The stepless dimming circuit according to claim 1, characterized in that: The power input end of the constant current drive module U5 is grounded through capacitor C23; the open circuit protection voltage adjustment end of the constant current drive module U5 is grounded through a capacitor C22 and a resistor R55 connected in parallel; the PWM dimming input end of the constant current drive module U5 is connected to the control module U6 through a resistor R48; the output end of the constant current drive module U5 is connected to the output end of the rectifier and filter circuit through a diode D21, the cathode of the diode D21 is connected to the output end of the rectifier and filter circuit, the negative end is grounded through a capacitor C25, and a parallel power supply R52 and a capacitor C31 are arranged between the positive end and the negative end.

3. The stepless dimming circuit according to claim 2, characterized in that: The current limiting resistor is composed of a resistor R57 and a resistor R58 connected in series, and the control module U6 is grounded through a resistor R51 and a buzzer BZ1 in sequence.

4. The stepless dimming circuit according to claim 2, characterized in that: The night light control circuit includes an NPN transistor Q16, the emitter of the transistor Q16 is grounded, the base of the transistor Q16 is connected to the control module U6 through a resistor R65, and a resistor R64 is connected between the base and emitter of the transistor Q16; The collector of transistor Q16 is connected to the output end of the auxiliary power supply through light-emitting diode D22 and a pull-up resistor in sequence. The pull-up resistor is also connected to a switch SW3. The switch SW3 is provided with a left terminal, a right terminal and a middle terminal. The left terminal is grounded, the right terminal is connected to the output end of the auxiliary power supply, and the middle terminal is connected to the control module U6.

5. The stepless dimming circuit according to claim 1, characterized in that: The front stage of the rectifier and filter circuit is also provided with an EMC circuit, which includes a varistor, an X capacitor C27, a resistor R53 and a resistor R54 arranged between the live wire L and the neutral wire N, and the two ends of the varistor and the X capacitor C27 are respectively connected to the live wire L and the neutral wire L; the resistor R53 and the resistor R54 are connected in series, and are respectively connected to the live wire L and the neutral wire L after being connected in series; a primary common mode inductor T1 and a secondary common mode inductor T2 are also provided, and are connected to the rectifier and filter circuit after passing through the secondary common mode inductor T2.

6. The stepless dimming circuit according to claim 1, characterized in that: The main control circuit is also connected to a mains power detection circuit.

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