Intelligent lamp, dimming control circuit thereof, and dimming control method of intelligent lamp

Abstract

The application discloses an intelligent lamp, a dimming control circuit thereof, and a dimming control method of the intelligent lamp. The dimming control circuit comprises input terminals and output terminals. A phase-cutting circuit is arranged between the input terminals and the output terminals. The phase-cuting circuit receives a control signal output by a control circuit. A compensation circuit is connected between the output terminals. The compensation circuit comprises a rectifier circuit. An output end of the rectifier circuit is connected with a compensation loop. The compensation loop comprises a compensation resistor module and a current control device connected in series. The compensation circuit further comprises a control loop. The control loop comprises a controllable voltage stabilizer. A control end of the controllable voltage stabilizer receives a voltage output by a voltage dividing circuit. The voltage output by the voltage dividing circuit increases with the increase of a voltage output by the output terminals. The intelligent lamp has the dimming control circuit. The method uses the circuit to dim. The application can avoid noise generated by a driving circuit and can avoid flicker of an LED chip.

Description

Technical Field

[0001] This invention relates to the technical field of intelligent lighting control, and more particularly to a dimming control circuit for such intelligent lighting, as well as a dimming control method for such intelligent lighting. Background Technology

[0002] With the development of smart home technology, home appliances are becoming increasingly intelligent, and smart lighting is a common type of smart appliance. Existing smart lighting fixtures typically incorporate LED chips, and the brightness of these chips can be adjusted via a dimmer, thus enabling dimming of the lighting fixture.

[0003] With the continuous development of dimming technology, various dimming techniques have emerged. Among them, SCR dimming technology is a common dimming technology. This technology has the advantage of simple installation and is fully compatible with traditional LED light source drivers in terms of input and output circuit interfaces. If it is necessary to replace the traditional LED light source driver with the SCR dimming method, it is only necessary to replace the traditional LED light source driver with an LED light source driver that supports SCR dimming, and replace the original wall switch with a SCR dimmer. Therefore, SCR dimming technology is widely used in the process of upgrading smart lighting fixtures.

[0004] Currently, thyristor dimming technology has two dimming methods: leading-edge control and trailing-edge control. For example, the invention patent application with publication number CN112738943A describes the specific waveforms for these two control methods. Regardless of whether it's leading-edge or trailing-edge control, the sinusoidal signal needs to be chopped according to the dimming ratio, typically using a phase-cutting circuit. The phase-cutting circuit incorporates switching devices, such as field-effect transistors (FETs), and the chopping ratio is adjusted by controlling the FET's on / off time.

[0005] However, the phase-cutting circuit needs to be used in conjunction with the driver power supply of the smart lighting fixture. Since different driver power supplies have different requirements for the phase-cutting circuit, incompatibility issues arise between the phase-cutting circuit and the driver circuit, leading to significant noise during dimming. For example, when the chopping ratio is high, the waveform output by the phase-cutting circuit is severely distorted, resulting in a lower output voltage and causing significant noise in the driver circuit, negatively impacting the user experience. Summary of the Invention

[0006] The primary objective of this invention is to provide a dimming control circuit for intelligent lighting fixtures that can effectively reduce noise caused by excessively low output voltage after phase switching.

[0007] A second objective of this invention is to provide an intelligent lamp having the dimming control circuit described above.

[0008] A third objective of this invention is to provide a dimming control method for the aforementioned intelligent lighting fixtures.

[0009] To achieve the aforementioned first objective, the dimming control circuit for the intelligent lighting fixture provided by this invention includes an input terminal and an output terminal. A phase-cutting circuit is provided between the input terminal and the output terminal, and the phase-cutting circuit receives a control signal output by the control circuit. A compensation circuit is connected between the output terminals. The compensation circuit includes a rectifier circuit, and the output terminal of the rectifier circuit is connected to a compensation loop. The compensation loop includes a compensation resistor module connected in series and a current control device. The compensation circuit also includes a control loop, which includes a controllable voltage regulator. The control terminal of the controllable voltage regulator receives the voltage output by a voltage divider circuit. The voltage output by the voltage divider circuit increases as the voltage output by the output terminal increases. The output voltage of the controllable voltage regulator decreases as the output voltage of the voltage divider circuit increases. The controllable voltage regulator outputs a signal to the control terminal of the current control device, and the conduction current of the current control device increases as the output voltage of the controllable voltage regulator increases.

[0010] As can be seen from the above scheme, a compensation circuit is set between the output terminals to compensate for the voltage output of the phase-cutting circuit. When the output voltage at the output terminals is low, the voltage output by the voltage divider circuit is also low, resulting in a low voltage received at the control terminal of the controllable voltage regulator, but a higher output voltage. This causes the conduction current of the current control device to increase. Since the current control device is connected in series with the compensation resistor module, when the conduction current of the current control device increases, the voltage of the compensation circuit increases, and the compensation voltage applied between the output terminals also increases. In this way, when the output voltage at the output terminals is low, the compensation circuit can provide a higher compensation voltage, thereby preventing the drive power supply from generating noise due to excessively low voltage.

[0011] A preferred embodiment is that the compensation resistor module includes two sets of compensation resistors, with the current control device connected in series between the two sets of compensation resistors.

[0012] Therefore, by setting two sets of compensation resistors connected in series, the resistance value of the compensation resistor module can be increased, thereby improving the compensation voltage.

[0013] A preferred embodiment is that at least one set of compensation resistors includes two or more compensation resistors connected in parallel.

[0014] As can be seen, by setting multiple compensation resistors in parallel, if one compensation resistor malfunctions, other compensation resistors in the same group will continue to operate, thus ensuring the stability of the compensation resistor module.

[0015] A further embodiment is that the voltage divider circuit includes a first voltage divider module and a second voltage divider module connected in series. The first voltage divider module is connected to the output terminal of the rectifier circuit, the second voltage divider module is grounded, and the control terminal of the controllable voltage regulator is connected between the first voltage divider module and the second voltage divider module. A first Zener diode is also provided between the first voltage divider module and the control terminal of the controllable voltage regulator.

[0016] It can be seen that the voltage output of the voltage divider circuit can be guaranteed to fluctuate within a certain range by the first Zener diode, avoiding the voltage output of the voltage divider circuit being too high or too low. This allows the output voltage of the controllable voltage regulator to fluctuate within a certain range, thereby allowing the conduction current of the current control device to fluctuate within a certain range.

[0017] A further option is that the second voltage divider module includes a first voltage divider resistor and a second voltage divider resistor connected in parallel, with the second voltage divider resistor connected in series with the voltage divider control device.

[0018] Therefore, by controlling the on and off states of the voltage divider controller, the resistance value of the second voltage divider module can be changed, thereby adjusting the voltage range output by the voltage divider circuit and giving the compensation circuit a larger compensation range.

[0019] A further approach is to connect the control terminal of the voltage divider controller to the voltage divider control branch, which is equipped with a second Zener diode connected between the output terminal of the rectifier circuit and the control terminal of the voltage divider controller.

[0020] As can be seen, if the output voltage at the output terminal is low, the second Zener diode will not conduct, and the second voltage divider resistor will not be connected to the circuit, thereby increasing the resistance value of the second voltage divider module. In fact, the conduction of the voltage divider control device is determined by the magnitude of the output voltage. Therefore, the conduction current of the current control device can be adjusted according to the magnitude of the output voltage, resulting in a wider range of compensation voltage.

[0021] A further approach is to use a field-effect transistor (FET) as the current control device.

[0022] To achieve the second objective mentioned above, the intelligent lighting fixture provided by the present invention includes a driving circuit, an LED chip, and a dimming control circuit for the intelligent lighting fixture. The dimming control circuit outputs a signal to the driving circuit, and the driving circuit supplies power to the LED chip.

[0023] To achieve the third objective mentioned above, the dimming control method for intelligent lighting provided by the present invention is applied to an intelligent lighting fixture, which is equipped with the dimming control circuit of the intelligent lighting fixture described above. The method includes: when the output voltage of the output terminal increases, the conduction current of the current control device decreases, and the compensation voltage applied to the output terminal decreases; when the output voltage of the output terminal decreases, the conduction current of the current control device increases, and the compensation voltage applied to the output terminal increases.

[0024] As can be seen from the above scheme, when the voltage output from the output terminal decreases, the compensation voltage output by the compensation circuit increases, thereby compensating for the voltage output from the output terminal. Conversely, when the output voltage from the output terminal increases, the compensation voltage decreases, preventing the voltage applied to the LED chip from being too low and causing noise.

[0025] Furthermore, the method also includes: when the output voltage of the output terminal is higher than a preset voltage threshold, the voltage divider controller is turned on, and when the output voltage of the output terminal is lower than the preset voltage threshold, the voltage divider controller is turned off.

[0026] Therefore, by controlling the on and off states of the voltage divider controller, the resistance value of the second voltage divider resistor module can be changed, thereby altering the conduction current of the current controller and thus changing the compensation voltage. This enhances the compensation capability of the compensation circuit when the output voltage at the output terminal is lower than a preset voltage threshold, resulting in a wider compensation voltage range. Attached Figure Description

[0027] Figure 1 This is an electrical schematic diagram of an embodiment of the dimming control circuit for the intelligent lighting fixture of the present invention.

[0028] Figure 2 This is the electrical schematic diagram of the compensation circuit in an embodiment of the dimming control circuit of the intelligent lighting fixture of the present invention.

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0030] The intelligent lamp of the present invention has a driving circuit, an LED chip, and uses a silicon controlled rectifier (SCR) dimmer for dimming. The intelligent lamp is provided with a dimming control circuit, which can output a signal to the driving circuit, and the driving circuit supplies power to the LED chip.

[0031] See Figure 1The dimming control circuit of the intelligent lighting fixture has two input terminals, N1 and L1, which receive AC power. The dimming control circuit also has two output terminals, N2 and L2, which output AC power to the drive circuit. A phase-cutting circuit 11 is connected between the input and output terminals. The phase-cutting circuit 11 includes two switching devices, namely field-effect transistors Q4 and Q5. The phase-cutting circuit 11 also receives control signals from the control circuit 13, which includes a microcontroller. The microcontroller outputs control signals to the field-effect transistors Q4 and Q5 to control their conduction and cutoff. In addition, the dimming control circuit also includes a power supply circuit 12, which obtains AC power from the input terminals N1 and L1 and converts it into low-voltage DC power before supplying power to the control circuit 13.

[0032] Input terminals N1 and L1 receive a sinusoidal signal, which flows through field-effect transistors Q4 and Q5. Control circuit 13 determines the chopping ratio of the sinusoidal signal based on the dimming ratio, and calculates the on-time and off-time of field-effect transistors Q4 and Q5 accordingly. It then outputs control signals to control field-effect transistors Q4 and Q5, thereby chopping the input sinusoidal signal. When the user desires a lower LED brightness, the control signal output by control circuit 13 results in a shorter on-time for field-effect transistors Q4 and Q5, meaning a higher chopping ratio. This distorts the voltage waveform output from output terminals N2 and L2. Consequently, the voltage output to the subsequent driver circuit is also distorted, causing the LED chip to flicker and generating significant noise in the driver circuit.

[0033] To avoid this problem, this embodiment includes a compensation circuit 14, which is connected between the two output terminals N2 and L2. (See also...) Figure 2 The compensation circuit 14 is equipped with a rectifier circuit DB1, which is a full-bridge rectifier circuit. It receives the AC power output from the output terminals N2 and L2 and converts it into DC power. When the voltage of the AC power output from the output terminals N2 and L2 is high, the voltage of the rectified DC power is also high; when the voltage of the AC power output from the output terminals N2 and L2 is low, the voltage of the rectified DC power is also low.

[0034] The compensation circuit 14 also includes a compensation loop. In this embodiment, the compensation loop includes a series-connected compensation resistor module and a current control device. The compensation resistor module includes two sets of compensation resistors, each set comprising two or more compensation resistors connected in parallel. For example, the first set includes three parallel compensation resistors R25, R26, and R27, and the second set includes three parallel compensation resistors R38, R40, and R41. The current control device is a field-effect transistor (FET) Q7, connected between the two sets of compensation resistors in series. Since the on-state current of the FET Q7 can vary with the gate voltage, when the on-state current of the FET Q7 increases, the current in the compensation loop increases, and the current flowing through the two sets of compensation resistors also increases. Therefore, the voltage of the compensation loop increases, which means the compensation voltage of the compensation circuit 14 increases. Conversely, when the on-state current of the field-effect transistor Q7 decreases, the current in the compensation circuit decreases, and the current flowing through the two sets of compensation resistors also decreases. Therefore, the voltage of the compensation circuit decreases, which means the compensation voltage of compensation circuit 14 decreases. Thus, the magnitude of the compensation voltage can be controlled by controlling the magnitude of the on-state current of the current control device.

[0035] In this embodiment, the compensation circuit includes a control loop, which contains a controllable voltage regulator U3. The controllable voltage regulator U3 is connected in series with resistors R23 and R30, and its first terminal is connected to point A. Point A is connected to the gate of the field-effect transistor Q7 through resistors R33 and R34. Since the on-current of the field-effect transistor Q7 is related to the gate voltage (i.e., the higher the gate voltage of Q7, the larger the on-current), the on-current of Q7 can be controlled by controlling the voltage at point A.

[0036] The control terminal of the controllable voltage regulator U3 is connected to point B. Therefore, by controlling the voltage at point B, the voltage at the first terminal of the controllable voltage regulator U3 can be controlled, which means controlling the voltage at point A. To control the voltage at point B, a voltage divider circuit is set in the compensation circuit. In this embodiment, the voltage divider circuit includes a first voltage divider module and a second voltage divider module connected in series. The first voltage divider module includes resistors R24, R31, and R32 connected in series, and resistor R32 is connected in parallel with the first Zener diode ZD1. The second voltage divider module includes two first voltage divider resistors R43 and second voltage divider resistor R77 connected in parallel, and the second voltage divider resistor R77 is connected in series with the voltage divider controller, which in this embodiment is a field-effect transistor Q9.

[0037] from Figure 2As can be seen, the first voltage divider module is connected to the output terminal of the rectifier circuit DB1, the second voltage divider module is grounded, and the control terminal of the controllable voltage regulator U3 is connected between the first and second voltage divider modules, that is, point B is between the first and second voltage divider modules. When the voltage between output terminals N2 and L2 increases, the voltage at point B also increases, causing the voltage at the control terminal of the controllable voltage regulator U3 to increase; when the voltage between output terminals N2 and L2 decreases, the voltage at point B also decreases, causing the voltage at the control terminal of the controllable voltage regulator U3 to decrease. In this embodiment, the output voltage of the controllable voltage regulator U3 decreases as the output voltage of the voltage divider circuit increases, that is, when the voltage at point B increases, the voltage at point A decreases, therefore the voltage at point A and the voltage at point B are in opposite phase.

[0038] Since the first Zener diode ZD1 on the first voltage divider module has a turn-on voltage, that is, the voltage difference across the first Zener diode ZD1 needs to be greater than the turn-on threshold to conduct, the first Zener diode ZD1 does not conduct when the voltage output by the rectifier circuit DB1 is low, and the first Zener diode ZD1 conducts when the voltage output by the rectifier circuit DB1 is high. After the first Zener diode ZD1 conducts, the voltage across the first Zener diode ZD1 can be kept stable, so that the voltage at point B can vary within a certain range.

[0039] In addition, a voltage divider control branch is provided in the compensation circuit 14. The voltage divider control branch includes resistors R72, R73, and R75 connected in series, a second Zener diode ZD4, and a resistor R71. Resistor R71 is connected in parallel with capacitor C17. The gate of the field-effect transistor Q9, i.e., the control terminal, is connected to point C, which is located between the second Zener diode ZD4 and resistor R71. The two ends of the voltage divider control branch are connected to the output terminal of the rectifier circuit DB1 and ground, respectively. Therefore, when the voltage output of the rectifier circuit DB1 increases, the voltage at point C increases; when the voltage output of the rectifier circuit DB1 decreases, the voltage at point C decreases.

[0040] Because the voltage divider control branch includes a second Zener diode ZD4, and ZD4 has a turn-on voltage, when the voltage difference across ZD4 is small, for example, when the output voltage at the output terminal is less than a preset voltage threshold, ZD4 does not conduct. At this time, point C shows a low-level signal, and the MOSFET Q9, acting as the voltage divider control device, is cut off. In this case, the second voltage divider module only has resistor R43, which has a relatively large resistance value. When the output voltage at the output terminal is higher than the preset voltage threshold, ZD4 conducts. At this time, point C shows a low-high level signal, and MOSFET Q9, acting as the voltage divider control device, conducts. In this case, resistor R77 is connected to the circuit, and the resistance value of the second voltage divider module is the parallel resistance of resistors R43 and R77, which is relatively small. This embodiment achieves voltage compensation in two different voltage ranges by controlling the conduction and cutoff of MOSFET Q9.

[0041] If the voltage between output terminals N2 and L2 fluctuates within the first voltage range, for example, between 170V and 250V, the second Zener diode ZD4 remains on, point C is at a high level, causing the MOSFET Q9 to conduct, and resistor R77 is connected in the circuit. When phase cutting is severe, i.e., when the chopping ratio is high, the voltage waveform between output terminals N2 and L2 is severely distorted, resulting in a lower output voltage from the rectifier circuit DB1, for example, between 170V and 180V. This leads to a lower voltage at point B, a lower control terminal voltage for the controllable voltage regulator U3, resulting in a higher voltage at point A and a larger on-state current for the MOSFET Q7. When the voltage between output terminals N2 and L2 increases, the voltage at point B also increases, causing a decrease in the voltage at point A and a reduction in the on-state current of the MOSFET Q7.

[0042] When the on-state current of MOSFET Q7 increases, the current in the compensation circuit increases, and the current flowing through the two sets of compensation resistors also increases. Therefore, the voltage in the compensation circuit rises, which means the compensation voltage of compensation circuit 14 rises. It can be seen that the voltage between output terminals N2 and L2...

[0043] When the voltage is low, the compensation circuit 14 can output a higher compensation voltage, thereby avoiding the problem of LED chip flickering and the driving circuit generating noise due to the low voltage received by the driving circuit 5.

[0044] If the voltage between output terminals N2 and L2 fluctuates within the second voltage range, for example, between 90V and 170V, the second Zener diode ZD4 will not conduct, the MOSFET Q9 will be in the off state, resistor R77 will not be connected to the circuit, and the second voltage divider module will only have resistor R43.

[0045] Compared to the on state of MOSFET Q9, the resistance of the second voltage divider module is larger, causing the voltage at point B0 to vary within another voltage range. Consequently, the voltage at point A will also vary within another voltage range.

[0046] When the voltage between output terminals N2 and L2 fluctuates between 90V and 170V, MOSFET Q9 will remain off. When the voltage between output terminals N2 and L2 decreases, A...

[0047] The voltage at the point will increase, causing the on-state current of the field-effect transistor Q7 to continue to increase, which in turn increases the compensation voltage of the compensation circuit 514. Therefore, this embodiment can achieve voltage compensation over a wide range from 90V to 250V between the output terminals N2 and L2.

[0048] Of course, the above-mentioned solution is only a preferred embodiment of the present invention. In actual application, there can be more variations, such as changes in the selection of various device models, or changes in the number of selected voltage divider resistors. These changes do not affect the implementation of the present invention and should be included within the scope of protection of the present invention.

Claims

1. A dimming control circuit for intelligent lighting fixtures, including: The system includes an input terminal and an output terminal, with a phase-cutting circuit provided between the input terminal and the output terminal. The phase-cutting circuit receives control signals output by the control circuit. Its features are: A compensation circuit is connected between the output terminals. The compensation circuit includes a rectifier circuit. The output terminal of the rectifier circuit is connected to a compensation loop. The compensation loop includes a compensation resistor module and a current control device connected in series. The compensation circuit further includes a control loop, which includes a controllable voltage regulator. The control terminal of the controllable voltage regulator receives the voltage output from the voltage divider circuit. The voltage output by the voltage divider circuit increases as the voltage output from the output terminal increases. The output voltage of the controllable voltage regulator decreases as the output voltage of the voltage divider circuit increases. The controllable voltage regulator outputs a signal to the control terminal of the current control device. The conduction current of the current control device increases as the output voltage of the controllable voltage regulator increases. The voltage divider circuit includes a first voltage divider module and a second voltage divider module connected in series. The first voltage divider module is connected to the output terminal of the rectifier circuit, the second voltage divider module is grounded, and the control terminal of the controllable voltage regulator is connected between the first voltage divider module and the second voltage divider module. A first voltage regulator tube is also provided between the first voltage divider module and the controllable voltage regulator source control terminal; The second voltage divider module includes a first voltage divider resistor and a second voltage divider resistor connected in parallel, and the second voltage divider resistor is connected in series with the voltage divider controller. The control terminal of the voltage divider controller is connected to the voltage divider control branch, and the voltage divider control branch is provided with a second Zener diode, which is connected between the output terminal of the rectifier circuit and the control terminal of the voltage divider controller. When the voltage between the output terminals fluctuates within the first voltage range, the second Zener diode can remain in the conducting state, so that the voltage divider control device is in the conducting state. When the voltage between the output terminals fluctuates within a second voltage range, the voltage divider controller remains in an open state, wherein the first voltage range is higher than the second voltage range.

2. The dimming control circuit for the intelligent lighting fixture according to claim 1, characterized in that: The compensation resistor module includes two sets of compensation resistors, and the current control device is connected between the two sets of compensation resistors in series.

3. The dimming control circuit for intelligent lighting fixtures according to claim 2, characterized in that: At least one set of the compensation resistor group includes two or more compensation resistors connected in parallel.

4. The dimming control circuit for the intelligent lighting fixture according to any one of claims 1 to 3, characterized in that: The current control device is a field-effect transistor.

5. A smart lighting fixture, characterized in that, include: The system includes a driving circuit, an LED chip, and a dimming control circuit for a smart lamp as described in any one of claims 1 to 4, wherein the dimming control circuit outputs a signal to the driving circuit, and the driving circuit supplies power to the LED chip.

6. A dimming control method for an intelligent lighting fixture, wherein the intelligent lighting fixture is provided with a dimming control circuit as described in any one of claims 1 to 4, characterized in that, The method includes: When the output voltage of the output terminal increases, the conduction current of the current control device decreases, and the compensation voltage applied to the output terminal decreases. When the output voltage of the output terminal decreases, the conduction current of the current control device increases, and the compensation voltage applied to the output terminal increases.

7. A dimming control method for an intelligent lighting fixture, wherein the intelligent lighting fixture is provided with a dimming control circuit as described in claim 1, characterized in that, The method includes: When the output voltage of the output terminal increases, the conduction current of the current control device decreases, and the compensation voltage applied to the output terminal decreases; when the output voltage of the output terminal decreases, the conduction current of the current control device increases, and the compensation voltage applied to the output terminal increases. Furthermore, when the output voltage at the output terminal is higher than a preset voltage threshold, the voltage divider controller is turned on, and when the output voltage at the output terminal is lower than the preset voltage threshold, the voltage divider controller is turned off.

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