Dimming circuit and lighting device

Abstract

The application provides a dimming circuit and a lighting device, and belongs to the technical field of lighting control. The input end of a control module is connected with a front-stage circuit, the first output end of the control module is connected with a dimming module, the second output end of the control module is connected with the first end of a correction module, the second end of the correction module is connected with the first end of a constant-voltage lamp strip, and the output end of the dimming module and the third end of the correction module are both connected with the second end of the constant-voltage lamp strip. The control module is used for adjusting the frequency of the pulse width modulation signal sent by the front-stage circuit to obtain a target pulse width modulation signal. The dimming module controls the brightness of the constant-voltage lamp strip under the action of the target pulse width modulation signal. The correction module corrects the terminal voltage of the constant-voltage lamp strip under the action of the target pulse width modulation signal and the timing signal issued by the control module. The application can improve the dimming quality of the constant-voltage lamp strip transmission and achieve the effect that the brightness of the constant-voltage lamp strip under the same dimming signal is consistent.

Description

Technical Field

[0001] This application relates to the field of lighting control technology, and more specifically, to a dimming circuit and a lighting device. Background Technology

[0002] In recent years, with the continuous expansion of the lighting market, people's dimming needs for lighting installations have become increasingly diversified, leading to a proliferation of lighting products that meet different dimming requirements. However, the power that a single dimming controller can provide is limited, necessitating the use of multiple dimming controllers for large-space lighting scenarios. Furthermore, the complexity of dimming controllers' control capabilities results in high production costs, leading to higher application costs for lighting controlled by multiple dimming controllers.

[0003] Therefore, existing technologies often use a single dimming controller connected in series with multiple dimming units to control multiple constant-voltage LED strips to meet the lighting needs of large spaces. Specifically, the dimming controller sends dimming control pulse signals to the first-level dimming unit. The first-level dimming unit processes these pulse signals to obtain the voltage change signal between the positive and negative terminals of the constant-voltage LED strip, and dims the strip based on this signal. The second-level dimming unit directly obtains the voltage change signal from the positive and negative terminals of the first-level LED strip and controls it accordingly. This process continues to control multiple constant-voltage LED strips.

[0004] However, when using this solution for large-space scene lighting, there is a problem that different constant voltage LED strips have different turn-off voltages, which increases the time it takes for the subsequent dimming unit to collect a high level from the constant voltage LED strip, resulting in inconsistent brightness of the constant voltage LED strip. Utility Model Content

[0005] The purpose of this application is to provide a dimming circuit and a lighting device that can improve the dimming quality of constant voltage light strip transmission and achieve consistent brightness of the constant voltage light strip under the same dimming signal.

[0006] The embodiments of this application are implemented as follows: A first aspect of this application provides a dimming circuit, which includes: a control module, a dimming module, and a correction module; The input terminal of the control module is connected to the pre-amplifier circuit, the first output terminal of the control module is connected to the dimming module, the second output terminal of the control module is connected to the first terminal of the calibration module, the second terminal of the calibration module is connected to the first terminal of the constant voltage LED strip, and the output terminal of the dimming module and the third terminal of the calibration module are both connected to the second terminal of the constant voltage LED strip. The control module is used to adjust the frequency of the pulse width modulation signal sent by the front-end circuit to obtain the target pulse width modulation signal, and then send the target pulse width modulation signal to the dimming module and the correction module respectively. The dimming module controls the brightness of the constant voltage LED strip under the action of the target pulse width modulation signal; the correction module corrects the terminal voltage of the constant voltage LED strip under the action of the target pulse width modulation signal and the timing signal sent by the control module.

[0007] As one possible implementation, the correction module in the dimming circuit described above includes: a control unit and a correction unit; The first input terminal of the control unit is connected to the first output terminal of the control module and is used to receive the target pulse width modulation signal. The second input terminal of the control unit is connected to the first output terminal of the control module and is used to receive the timing signal. The output of the control unit is connected to the control unit of the correction unit. Under the action of the target pulse width modulation signal and the timing signal, the control unit sends the first control signal to the correction unit. The first end of the correction unit is connected to the first end of the constant voltage LED strip, and the second end of the correction unit is connected to the second end of the constant voltage LED strip. The correction unit corrects the terminal voltage of the constant voltage LED strip under the action of the first control signal.

[0008] As one possible implementation, the control unit in the dimming circuit described above includes: a D flip-flop; Both the first and second input terminals of the D flip-flop are connected to the first output terminal of the control module, and the output terminal of the D flip-flop is connected to the control terminal of the correction unit.

[0009] As one possible implementation, the correction unit in the dimming circuit described above includes: a first resistor, a second resistor, a third resistor, a first transistor, and a second transistor; One end of the first resistor is connected to the output of the D flip-flop, and the other end of the first resistor is connected to the base of the first transistor and the collector of the second transistor. The collector of the first transistor is connected to the first end of the constant voltage LED strip via the second resistor. The emitter of the first transistor is connected to one end of the third resistor and the base of the second transistor. The other end of the third resistor and the emitter of the second transistor are both connected to the second end of the constant voltage LED strip.

[0010] As one possible implementation, the dimming circuit described above also includes: a power supply module; The first output terminal of the power supply module is connected to the first end of the constant voltage light strip, and the second output terminal of the power supply module is connected to the dimming module.

[0011] As one possible implementation, the dimming module in the dimming circuit described above includes: a driving unit and a dimming unit; The first input terminal of the drive unit is connected to the second output terminal of the control module, the output terminal of the drive unit is connected to the control terminal of the dimming unit, and the second input terminal of the drive unit and the input terminal of the dimming unit are both connected to the second output terminal of the power supply module and grounded. The driving unit is used to output a second control signal to the dimming unit under the action of the target pulse width modulation signal, and the dimming unit sends a dimming signal to the constant voltage lamp strip under the control of the second control signal.

[0012] As one possible implementation, the driving unit in the dimming circuit described above includes: a first capacitor and a fourth resistor; One end of the first capacitor is connected to the second output terminal of the control module and one end of the fourth resistor, respectively. The other end of the fourth resistor is connected to the control terminal of the dimming unit, and the other end of the first capacitor is connected to the second output terminal of the power supply module and grounded.

[0013] As one possible implementation, the dimming unit in the dimming circuit described above includes: a metal-oxide-semiconductor transistor; The gate of the metal oxide semiconductor transistor is connected to the other end of the fourth resistor, the drain of the metal oxide semiconductor transistor is connected to the second end of the constant voltage lamp strip, and the source of the metal oxide semiconductor transistor is connected to the second output terminal of the power supply module and grounded.

[0014] As one possible implementation, the dimming module in the dimming circuit described above also includes: a fifth resistor, a sixth resistor, and a second capacitor; One end of the fifth resistor is connected to the other end of the fourth resistor. The other end of the fifth resistor is connected to one end of the sixth resistor, one end of the second capacitor, and the source of the metal-oxide-semiconductor transistor. The other end of the sixth resistor and the other end of the second capacitor are both connected to the second output terminal of the power supply module and grounded.

[0015] A second aspect of this application provides a lighting device, which includes a constant voltage light strip and the dimming circuit described in the first aspect.

[0016] The beneficial effects of the embodiments of this application include: This application provides a dimming circuit comprising a control module, a dimming module, and a correction module. A front-end circuit generates a pulse width modulation (PWM) signal in response to the user's dimming request. The control module receives the PWM signal from the front-end circuit and adjusts the frequency of the PWM signal based on the factory specifications of the subsequent constant-voltage LED strip to obtain a target PWM signal that matches the dimming frequency of the LED strip. The dimming module controls the brightness of the constant-voltage LED strip under the influence of the target PWM signal. The correction module corrects the voltage at both ends of the constant-voltage LED strip under the influence of the target PWM signal and a timing signal matching the target PWM signal. Specifically, the correction module outputs a corresponding constant current under the influence of the target PWM signal and the timing signal. The constant-voltage LED strip changes its voltage across its terminals under the influence of the constant current, ensuring that the voltage changes at both ends of the constant-voltage LED strip are consistent with the high and low level changes in the target PWM signal, thereby achieving high-quality dimming of the constant-voltage LED strip. This improves the dimming quality of the constant-voltage LED strip and ensures consistent brightness under the same dimming signal. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of an existing lighting control system; Figure 2 This is a schematic diagram of the structure of the first dimming circuit provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the second dimming circuit provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the third dimming circuit provided in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of the fourth dimming circuit provided in the embodiments of this application; Figure 6 This is a schematic diagram of the structure of the fifth dimming circuit provided in the embodiments of this application; Figure 7 This is a schematic diagram of the sixth dimming circuit provided in the embodiments of this application; Figure 8 This is a schematic diagram of the structure of a lighting device provided in an embodiment of this application.

[0019] Reference numerals: 10: Dimming circuit; 101: Control module; 102: Dimming module; 1021: Drive unit; 211: First capacitor; 212: Fourth resistor; 1022: Dimming unit; 221: Metal-oxide-semiconductor transistor; 1023: Fifth resistor; 1024: Sixth resistor; 1025: Second capacitor; 103: Correction module; 1031: Control unit; 311: D flip-flop; 1032: Correction unit; 321: First resistor; 322: Second resistor; 323: Third resistor; 324: First transistor; 325: Second transistor; 104: Power supply module; 20: Lighting device; 201: Constant voltage light strip. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this application, it should be noted that the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. It should also be noted that, unless otherwise expressly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0024] Currently, large-space scene lighting often uses a single dimming controller to control multiple dimming units to achieve dimming control of multiple constant-voltage light strips. Specifically, the dimming controller provides a dimming control pulse width modulation signal to the subsequent dimming units. The first-level dimming unit receives this dimming control pulse width modulation signal and controls the brightness of the first-level constant-voltage light strip connected to it based on the received dimming control pulse width modulation signal. The second-level dimming unit collects the terminal voltages of the positive and negative terminals of the first-level constant-voltage light strip and controls the terminal voltages of the corresponding second-level constant-voltage light strip based on the terminal voltages. This process continues, with each subsequent dimming unit collecting the terminal voltages of the positive and negative terminals of the previous-level constant-voltage light strip as the dimming control signal for the corresponding constant-voltage light strip, thus completing the dimming control of multiple constant-voltage light strips. However, this solution suffers from the problem that the turn-off voltages of the LEDs in different constant-voltage light strips are different. This leads to an increase in the duration of the high-level signal collected by the subsequent dimming unit from the previous constant-voltage light strip, resulting in inconsistent brightness across the multiple constant-voltage light strips.

[0025] Figure 1 See the schematic diagram of an existing lighting control system. Figure 1 The dimming controller is directly connected to the input of the first-level dimming unit, and the output of the first-level dimming unit is connected to the first-level constant-voltage LED strip. The input of the second-level dimming unit is connected to the positive and negative terminals of the first-level constant-voltage LED strip, and so on, with the input of the nth-level dimming unit connected to the positive and negative terminals of the (n-1)th-level constant-voltage LED strip. Only the first-level dimming unit directly obtains its dimming control signal from the dimming controller. The second-level dimming unit and all subsequent dimming units use the terminal voltage of the constant-voltage LED strip corresponding to the previous-level dimming unit as the dimming control signal to control the corresponding constant-voltage LED strip. In this way, the dimming control unit only needs to have pulse width modulation signal processing capabilities, reducing the number of dimming controllers and thus lowering the cost of lighting control in large-space scenes.

[0026] However, while this multi-stage series dimming unit and constant voltage LED strip method can achieve the function of controlling multiple constant voltage LED strips with a single dimming controller, the dimming effect cannot achieve the expected results. Specifically, because the turn-off voltages of different LED strip chips are different, some LED strips with higher turn-off voltages will experience a slow voltage drop across their positive and negative terminals when the dimming pulse width modulation signal is at a low level. After the voltage drops to the turn-off voltage, the drain of the metal-oxide-semiconductor transistor in the dimming unit can only be charged through other paths, and the charging current of other paths is smaller. This causes the voltage across the positive and negative terminals of the constant voltage LED strip to decrease slowly, which increases the time for the subsequent dimming unit to obtain the high-level pulse width modulation signal from the previous constant voltage LED strip. Consequently, the brightness of the subsequent constant voltage LED strip is inconsistent with that of the previous constant voltage LED strip, and so on. In large-space scenes, it is difficult to maintain consistent illumination brightness among multiple constant voltage LED strips.

[0027] To address this, this application provides a dimming circuit. A control module receives a pulse width modulation (PWM) signal from a pre-amplifier circuit. The control module adjusts the PWM signal based on the dimming frequency requirements of the constant-voltage LED strip to obtain a target PWM signal that meets the dimming needs. The dimming module controls the brightness of the constant-voltage LED strip under the influence of the target PWM signal. A calibration module adjusts the terminal voltages of the positive and negative terminals of the constant-voltage LED strip under the combined action of the target PWM signal and the timing signal from the control module, ensuring that the brightness of each constant-voltage LED strip matches the brightness indicated by the PWM signal, and that the brightness of each constant-voltage LED strip remains consistent. This improves the dimming quality of the constant-voltage LED strip transmission and achieves consistent brightness across multiple constant-voltage LED strips under the same dimming signal.

[0028] The dimming circuit and lighting device provided in the embodiments of this application will be explained in detail below with reference to the accompanying drawings.

[0029] Figure 2 For a schematic diagram of a dimming circuit provided in this application, see [link to schematic diagram]. Figure 2 The dimming circuit 10 provided in this application embodiment includes: a control module 101, a dimming module 102, and a correction module 103.

[0030] The input terminal of the control module 101 is connected to the pre-amplifier circuit, the first output terminal of the control module 101 is connected to the dimming module 102, the second output terminal of the control module 101 is connected to the first terminal of the correction module 103, the second terminal of the correction module 103 is connected to the first terminal of the constant voltage light strip 201, and the output terminal of the dimming module 102 and the third terminal of the correction module 103 are both connected to the second terminal of the constant voltage light strip 201.

[0031] Optionally, the pre-amplifier circuit includes a pulse width modulation (PWM) signal generator. The pre-amplifier circuit can generate a PWM signal based on the user's dimming requirements. The PWM information controls the power level via a fast switch to adjust the brightness of the constant voltage LED strip 201. The user can inform the pre-amplifier circuit of their dimming requirements via an external mechanical switch or touch button. Dimming requirements can be low light, normal light, high light, etc., and this application does not specifically limit these requirements.

[0032] It's worth noting that pulse width modulation (PWM) signals do not inherently change the output voltage of the dimming circuit; they only alter the switching time ratio within a fixed cycle. Specifically, the frequency in the PWM signal controls the number of switching cycles per unit time, while the duty cycle indicates the proportion of high-level time within the fixed cycle.

[0033] In addition, to ensure the stability of the lighting effect, the frequency of the pulse width modulation signal is generally set above 100 Hz. If the frequency of the pulse width modulation signal is below 100 Hz, it may cause the light to flicker, resulting in poor lighting effect. This application does not make a specific limitation on the frequency of the pulse width modulation signal.

[0034] Optionally, the first output terminal of the control module 101 is used to transmit the processed pulse width modulation signal to the dimming module 102, and the second output terminal of the control module 101 is used to transmit the processed pulse width modulation signal and the timing signal matching the processed pulse width modulation signal to the correction module 103.

[0035] Optionally, the first terminal of the correction module 103 serves as an input terminal of the correction module 103, through which the correction module 103 receives the processed pulse width modulation signal and the processed timing signal sent by the control module 101; the second terminal of the correction module 103 serves as an output terminal of the correction module 103, through which the correction module 103 corrects the terminal voltage of the first terminal of the constant voltage lamp strip 201; the third terminal of the correction module 103 serves as another output terminal of the correction module 103, through which the correction module 103 corrects the voltage of the second terminal of the constant voltage lamp strip 201.

[0036] The first end of the constant voltage LED strip 201 can be regarded as the positive input end of the constant voltage LED strip 201, and the second end of the constant voltage LED strip 201 can be regarded as the negative input end of the constant voltage LED strip 201.

[0037] It is worth noting that the constant voltage light strip 201 can be regarded as a light strip formed by multiple small light strips connected in parallel. Each small light strip is composed of multiple light-emitting diodes. For example, the constant voltage light strip is composed of 27 light-emitting diodes, of which 3 light-emitting diodes are connected in series to form a small light strip, and each small light strip is connected in parallel to form a constant voltage light strip.

[0038] The control module 101 is used to adjust the frequency of the pulse width modulation signal sent by the front-end circuit to obtain the target pulse width modulation signal, and send the target pulse width modulation signal to the dimming module 102 and the correction module 103 respectively.

[0039] Optionally, the control module 101 can be implemented by a microcontroller or by other controllers with pulse width modulation signal processing; this application does not specifically limit this.

[0040] Optionally, the control module 101 receives the pulse width modulation signal sent by the preceding circuit and adjusts the frequency of the pulse width modulation signal according to the hardware attributes of the controlled constant voltage lamp strip 201 to obtain a more stable and reliable target pulse width modulation signal. Simultaneously, the control module 101 also adjusts the timing signal corresponding to the pulse width modulation signal to ensure that the timing signal matches the adjusted target pulse width modulation signal. The frequency of the adjusted timing signal is always twice the frequency of the target pulse width modulation signal; this application does not specifically limit this.

[0041] The dimming module 102 controls the brightness of the constant voltage lamp strip 201 under the action of the target pulse width modulation signal; the correction module 103 corrects the terminal voltage of the constant voltage lamp strip 201 under the action of the target pulse width modulation signal and the timing signal sent by the control module 101.

[0042] Optionally, the dimming module 102 adjusts the switching frequency and on / off time of the built-in switch under the action of the target pulse width modulation signal, thereby adjusting the brightness of the constant voltage lamp strip 201.

[0043] Optionally, the correction module 103 adjusts the magnitude of the constant current under the action of the target pulse width modulation signal and the timing signal. The terminal voltage of the constant voltage lamp strip 201 changes under the action of the constant current, so that the terminal voltage of the constant voltage lamp strip 201 matches the brightness indicated by the target pulse width modulation signal, thereby ensuring the dimming effect of the constant voltage lamp strip 201.

[0044] It is worth noting that the target pulse width modulation signals received by the dimming module 102 and the correction module 103 have the same frequency and duty cycle, but the phase of the target pulse width modulation signal received by the correction module 103 is 180° different from the phase of the target pulse width modulation signal received by the dimming module 102.

[0045] In this embodiment, a dimming circuit is constructed using a control module, a dimming module, and a correction module. The front-end circuit generates a pulse width modulation (PWM) signal in response to the user's dimming request. The control module receives the PWM signal from the front-end circuit and adjusts the frequency of the PWM signal based on the factory specifications of the subsequent constant-voltage LED strip to obtain a target PWM signal that matches the dimming frequency of the subsequent constant-voltage LED strip. The dimming module controls the brightness of the constant-voltage LED strip under the influence of the target PWM signal. The correction module corrects the voltage at both ends of the constant-voltage LED strip under the influence of the target PWM signal and a timing signal matching the target PWM signal. Specifically, the correction module outputs a corresponding constant current under the influence of the target PWM signal and the timing signal. The constant-voltage LED strip changes its voltage across its terminals under the influence of the constant current, ensuring that the voltage changes at both ends of the constant-voltage LED strip are consistent with the high and low level changes in the target PWM signal, thereby achieving high-quality dimming of the constant-voltage LED strip. This improves the dimming quality of the constant-voltage LED strip and ensures consistent brightness under the same dimming signal.

[0046] In one alternative implementation, see [link to implementation details]. Figure 3 The correction module 103 in the dimming circuit 10 provided in this application embodiment includes: a control unit 1031 and a correction unit 1032.

[0047] The first input terminal of the control unit 1031 is connected to the first output terminal of the control module 101 for receiving the target pulse width modulation signal, and the second input terminal of the control unit 1031 is connected to the first output terminal of the control module 101 for receiving timing signals.

[0048] Optionally, the target pulse width modulation signal refers to the dimming control signal adapted to the dimming frequency of the constant voltage lamp strip, and the timing signal refers to the start and end times of the high level and the start and end times of the low level in the target pulse width modulation signal. The frequency of the timing signal is twice the frequency of the target pulse width modulation signal, and this application does not specifically limit it.

[0049] The output terminal of the control unit 1031 is connected to the control terminal of the correction unit 1032. Under the action of the target pulse width modulation signal and the timing signal, the control unit 1031 sends a first control signal to the correction unit 1032.

[0050] Optionally, the control unit 1031 generates a first control signal based on the target pulse width modulation signal and timing signal sent by the control module 101. The first control signal can be a high level or a low level, and this application does not specifically limit it.

[0051] The first end of the correction unit 1032 is connected to the first end of the constant voltage light strip 201, and the second end of the correction unit 1032 is connected to the second end of the constant voltage light strip 201. The correction unit 1032 corrects the terminal voltage of the constant voltage light strip 201 under the action of the first control signal.

[0052] Optionally, under the action of the first control signal sent by the control unit 1031, the correction unit 1032 outputs a constant current of a certain magnitude. The voltage at the positive and negative terminals of the constant voltage lamp strip 201 changes under the action of the constant current output by the correction unit 1032, thereby enabling the voltage at the positive and negative terminals of the constant voltage lamp strip 201 to decrease rapidly under the low-level pulse width modulation signal, ensuring that the time for the constant voltage lamp strip 201 to acquire the high-level pulse width modulation signal is the same as the proportion of the high-level time in the target pulse width modulation signal, thereby improving the dimming quality of the dimming circuit 10.

[0053] In one alternative implementation, see [link to implementation details]. Figure 4 The control unit 1031 in the dimming circuit 10 provided in this application embodiment includes: a D flip-flop 311.

[0054] The first and second input terminals of the D flip-flop 311 are both connected to the first output terminal of the control module 101, and the output terminal of the D flip-flop 311 is connected to the control terminal of the correction unit 1032.

[0055] Optionally, the input signal of the first input terminal of the D flip-flop 311 is the true value of the target pulse width modulation signal sent by the control module 101, such as 0 or 1; the second input terminal of the D flip-flop 311 is used to receive the timing signal sent by the control module 101, and the D flip-flop 311 sends the true value of the target pulse width modulation signal to the correction unit 1032 in sequence based on the timing signal.

[0056] In one alternative implementation, see [link to implementation details]. Figure 4 The correction unit 1032 in the dimming circuit 10 provided in this application embodiment includes: a first resistor 321, a second resistor 322, a third resistor 323, a first transistor 324, and a second transistor 325.

[0057] One end of the first resistor 321 is connected to the output terminal of the D flip-flop 311. The other end of the first resistor 321 is connected to the base of the first transistor 324 and the collector of the second transistor 325. The collector of the first transistor 324 is connected to the first end of the constant voltage LED strip 201 via the second resistor 322. The emitter of the first transistor 324 is connected to one end of the third resistor 323 and the base of the second transistor 325. The other end of the third resistor 323 and the emitter of the second transistor 325 are both connected to the second end of the constant voltage LED strip 201.

[0058] Optionally, the first resistor 321, the third resistor 323, the first transistor 324, and the second transistor 325 in the correction unit 1032 together constitute a transistor constant current circuit. Under the action of the first control signal output by the D flip-flop 311, the correction unit 1032 adjusts the resistance value of the third resistor 323 to output a constant current of a certain magnitude. The D flip-flop 311 drives the first transistor 324 to turn on and off through the first resistor 321.

[0059] Specifically, the magnitude of the constant current output by the correction unit 1032 is adjusted according to the working state of the constant voltage lamp strip 201. The constant current circuit in the correction unit 1032 can be implemented by other constant current circuits, and this application does not make any specific limitation on this.

[0060] In one alternative implementation, see [link to implementation details]. Figure 5 The dimming circuit 10 provided in this application embodiment also includes a power supply module 104.

[0061] The first output terminal of the power supply module 104 is connected to the first end of the constant voltage light strip 201, and the second output terminal of the power supply module 104 is connected to the dimming module 102.

[0062] Optionally, the power supply module 104 is specifically used to provide power supply voltage for the constant voltage LED strip 201 and the dimming module 102. The power supply module 104 can be implemented by a power chip or other power supply devices; this application does not specifically limit its implementation.

[0063] In one alternative implementation, see [link to implementation details]. Figure 6 The dimming module 102 in the dimming circuit 10 provided in this application embodiment includes: a driving unit 1021 and a dimming unit 1022.

[0064] The first input terminal of the drive unit 1021 is connected to the second output terminal of the control module 101, the output terminal of the drive unit 1021 is connected to the control terminal of the dimming unit 1022, and the second input terminal of the drive unit 1021 and the input terminal of the dimming unit 1022 are both connected to the second output terminal of the power supply module 104 and grounded.

[0065] The driving unit 1021 is used to output a second control signal to the dimming unit 1022 under the action of the target pulse width modulation signal, and the dimming unit 1022 sends a dimming signal to the constant voltage lamp strip 201 under the control of the second control signal.

[0066] Optionally, the second control signal is a control signal sent by the driving unit 1021 to the dimming unit 1022 based on the target pulse width modulation signal sent by the control module 101. Under the action of the second control signal, the dimming unit 1022 sends a corresponding dimming signal to the constant voltage lamp strip 201. Specifically, the second control signal can be a high level or a low level, and the dimming signal is specifically a power level electrical signal sufficient to drive the constant voltage lamp strip 201 to emit light.

[0067] In one alternative implementation, see [link to implementation details]. Figure 7 The driving unit 1021 in the dimming circuit 10 provided in this application embodiment includes: a first capacitor 211 and a fourth resistor 212.

[0068] One end of the first capacitor 211 is connected to the second output terminal of the control module 101 and one end of the fourth resistor 212, respectively. The other end of the fourth resistor 212 is connected to the control terminal of the dimming unit 1022, and the other end of the first capacitor 211 is connected to the second output terminal of the power supply module 104 and grounded.

[0069] Optionally, the first capacitor 211 is specifically used to filter the target pulse width modulation signal output by the control module 101, and the fourth resistor 212 generates the driving current of the dimming unit 1022 based on the filtered target pulse width modulation signal.

[0070] In one alternative implementation, see [link to implementation details]. Figure 7 The dimming unit 1022 in the dimming circuit 10 provided in this application embodiment includes a metal oxide semiconductor transistor 221.

[0071] The gate of the metal oxide semiconductor transistor 221 is connected to the other end of the fourth resistor 212, the drain of the metal oxide semiconductor transistor 221 is connected to the second end of the constant voltage lamp strip 201, and the source of the metal oxide semiconductor transistor 221 is connected to the second output terminal of the power supply module 104 and grounded.

[0072] Optionally, the metal oxide semiconductor transistor 221 is turned on or off under the action of the driving current output by the fourth resistor 212. When the metal oxide semiconductor transistor 221 is turned on, the constant voltage lamp strip 201 connected to it emits light. When the metal oxide semiconductor transistor 221 is turned off, the constant voltage lamp strip 201 connected to it is turned off.

[0073] In one alternative implementation, see [link to implementation details]. Figure 7 The dimming module 102 in the dimming circuit 10 provided in this application embodiment further includes: a fifth resistor 1023, a sixth resistor 1024, and a second capacitor 1025.

[0074] One end of the fifth resistor 1023 is connected to the other end of the fourth resistor 212. The other end of the fifth resistor 1023 is connected to one end of the sixth resistor 1024, one end of the second capacitor 1025, and the source of the metal oxide semiconductor transistor 221. The other ends of the sixth resistor 1024 and the other ends of the second capacitor 1025 are both connected to the second output terminal of the power supply module 104 and grounded.

[0075] Optionally, the fifth resistor 1023 serves as the gate-source discharge resistor between the gate and source of the metal-oxide-semiconductor transistor 221. It is mainly used to improve the circuit stability of the dimming module 102, ensure the accuracy of the dimming state of the dimming module 102, and avoid accidental touches.

[0076] Optionally, the sixth resistor 1024 is specifically used to sample the current output by the power supply module 104, and the second capacitor 1025 is specifically used to filter the electrical signal provided by the power supply module 104 to ensure the power supply stability of the constant voltage LED strip 201.

[0077] Figure 8 For a structural schematic diagram of a lighting device provided in this application, see [link to schematic diagram]. Figure 8 The lighting device 20 provided in this application includes the dimming circuit 10 and the constant voltage light strip 201 in the above specific embodiments. The working principle of the dimming circuit 10 is the same as that in the above specific embodiments, and will not be described again here.

[0078] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0079] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A dimming circuit, characterized in that, The dimming circuit includes: a control module, a dimming module, and a correction module; The input terminal of the control module is connected to the pre-amplifier circuit, the first output terminal of the control module is connected to the dimming module, the second output terminal of the control module is connected to the first terminal of the correction module, the second terminal of the correction module is connected to the first terminal of the constant voltage LED strip, and the output terminal of the dimming module and the third terminal of the correction module are both connected to the second terminal of the constant voltage LED strip. The control module is used to adjust the frequency of the pulse width modulation signal sent by the front-end circuit to obtain the target pulse width modulation signal, and send the target pulse width modulation signal to the dimming module and the correction module respectively. The dimming module controls the brightness of the constant voltage lamp strip under the action of the target pulse width modulation signal; the correction module corrects the terminal voltage of the constant voltage lamp strip under the action of the target pulse width modulation signal and the timing signal issued by the control module.

2. The dimming circuit according to claim 1, characterized in that, The calibration module includes: a control unit and a calibration unit; The first input terminal of the control unit is connected to the first output terminal of the control module for receiving the target pulse width modulation signal, and the second input terminal of the control unit is connected to the first output terminal of the control module for receiving the timing signal. The output terminal of the control unit is connected to the control terminal of the correction unit, and the control unit sends a first control signal to the correction unit under the action of the target pulse width modulation signal and the timing signal. The first end of the correction unit is connected to the first end of the constant voltage lamp strip, and the second end of the correction unit is connected to the second end of the constant voltage lamp strip. The correction unit corrects the terminal voltage of the constant voltage lamp strip under the action of the first control signal.

3. The dimming circuit according to claim 2, characterized in that, The control unit includes: a D flip-flop; The first and second input terminals of the D flip-flop are both connected to the first output terminal of the control module, and the output terminal of the D flip-flop is connected to the control terminal of the correction unit.

4. The dimming circuit according to claim 3, characterized in that, The correction unit includes: a first resistor, a second resistor, a third resistor, a first transistor, and a second transistor; One end of the first resistor is connected to the output terminal of the D flip-flop, and the other end of the first resistor is connected to the base of the first transistor and the collector of the second transistor. The collector of the first transistor is connected to the first end of the constant voltage lamp strip via the second resistor. The emitter of the first transistor is connected to one end of the third resistor and the base of the second transistor. The other end of the third resistor and the emitter of the second transistor are both connected to the second end of the constant voltage lamp strip.

5. The dimming circuit according to claim 1, characterized in that, The dimming circuit also includes: a power supply module; The first output terminal of the power supply module is connected to the first end of the constant voltage lamp strip, and the second output terminal of the power supply module is connected to the dimming module.

6. The dimming circuit according to claim 5, characterized in that, The dimming module includes: a driving unit and a dimming unit; The first input terminal of the driving unit is connected to the second output terminal of the control module, the output terminal of the driving unit is connected to the control terminal of the dimming unit, and both the second input terminal of the driving unit and the input terminal of the dimming unit are connected to the second output terminal of the power supply module and grounded. The driving unit is used to output a second control signal to the dimming unit under the action of the target pulse width modulation signal, and the dimming unit sends a dimming signal to the constant voltage lamp strip under the control of the second control signal.

7. The dimming circuit according to claim 6, characterized in that, The driving unit includes: a first capacitor and a fourth resistor; One end of the first capacitor is connected to the second output terminal of the control module and one end of the fourth resistor, the other end of the fourth resistor is connected to the control terminal of the dimming unit, and the other end of the first capacitor is connected to the second output terminal of the power supply module and grounded.

8. The dimming circuit according to claim 7, characterized in that, The dimming unit includes: a metal-oxide-semiconductor transistor; The gate of the metal oxide semiconductor transistor is connected to the other end of the fourth resistor, the drain of the metal oxide semiconductor transistor is connected to the second end of the constant voltage lamp strip, and the source of the metal oxide semiconductor transistor is connected to the second output terminal of the power supply module and grounded.

9. The dimming circuit according to claim 8, characterized in that, The dimming module also includes: a fifth resistor, a sixth resistor, and a second capacitor; One end of the fifth resistor is connected to the other end of the fourth resistor. The other end of the fifth resistor is connected to one end of the sixth resistor, one end of the second capacitor, and the source of the metal-oxide-semiconductor transistor. The other end of the sixth resistor and the other end of the second capacitor are both connected to the second output terminal of the power supply module and grounded.

10. A lighting device, characterized in that, The lighting device includes: a constant voltage light strip and a dimming circuit as described in any one of claims 1-9.

Images