Constant current control circuit and constant current control device

Abstract

The invention provides a constant current control circuit and a constant current control device. The circuit comprises a voltage conversion module, a current sampling module, a first constant current control module, a second constant current control module and an adjusting module. The current sampling module is used for collecting a first current flowing through the LED light source module, outputting a first sampling current to the first constant current control module according to the first current, and outputting a second sampling current to the second constant current control module; the first constant current control module receives the first dimming signal and generates a first control signal based on the first sampling current and the first dimming signal; the second constant current control module receives a second dimming signal and generates a second control signal based on the second sampling current and the second dimming signal; the adjusting module adjusts the feedback voltage according to the first control signal or the second control signal. According to the constant-current control circuit, an independent closed-loop two-stage constant-current control framework is adopted, the range coverage capability of current adjustment is greatly improved, and the use requirement of wide-range brightness adjustment is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of constant current control, and particularly relates to a constant current control circuit and a constant current control device. BACKGROUND

[0002] In the fields of LED (Light-Emitting Diode) lighting, photographic light supplement, etc., the brightness adjustment core of the LED light source depends on a constant current control circuit. As a current type load, the luminous brightness of the LED is directly related to the current flowing therethrough, and therefore the LED current needs to be ensured stable and precisely adjustable by the constant current control circuit to meet the lighting needs of different scenes. The existing LED constant current control scheme usually adopts a DCDC chip integrated with a dimming function. Although this scheme simplifies part of the circuit, the current regulation range coverage capability of the chip is limited, and the scheme cannot meet the use needs of wide range brightness adjustment. SUMMARY

[0003] The application embodiment provides a constant current control circuit and a constant current control device, which can solve the problem that the existing LED constant current control scheme usually adopts a DCDC chip integrated with a dimming function, the current regulation range coverage capability of the chip is limited, and the scheme cannot meet the use needs of wide range brightness adjustment.

[0004] In a first aspect, the application embodiment provides a constant current control circuit, which comprises a voltage conversion module (101), a current sampling module (102), a first constant current control module (103), a second constant current control module (104) and an adjustment module (105), wherein: The current sampling module (102) is configured to collect a first current flowing through an LED light source module (20) and is electrically connected to the first constant current control module (103) and the second constant current control module (104) respectively. The current sampling module (102) outputs a first sampling current to the first constant current control module (103) and a second sampling current to the second constant current control module (104) according to the first current. The first constant current control module (103) is configured to receive a first dimming signal and generate a first control signal based on the first sampling current and the first dimming signal. The second constant current control module (104) is configured to receive a second dimming signal and generate a second control signal based on the second sampling current and the second dimming signal. The adjusting module (105) is electrically connected with the voltage conversion module (101), the first constant current control module (103) and the second constant current control module (104) respectively, and is configured to adjust a feedback voltage of the voltage conversion module (101) according to the first control signal or the second control signal. In a possible implementation of the first aspect, the current sampling module (102) comprises a current sampling unit (1021), a first differential amplification unit (1022) and a second differential amplification unit (1023), wherein: The current sampling unit (1021) is electrically connected with the first differential amplification unit (1022) and the second differential amplification unit (1023) respectively, and is configured to collect a first current flowing through the LED light source module (20) and output a second current to the first differential amplification unit (1022) and the second differential amplification unit (1023) respectively; The first differential amplification unit (1022) is electrically connected with the first constant current control module (103), and is configured to amplify the second current by a first preset multiple to obtain a first sampling current and transmit the first sampling current to the first constant current control module (103); The second differential amplification unit (1023) is electrically connected with the second constant current control module (104), and is configured to amplify the second current by a second preset multiple to obtain a second sampling current and transmit the second sampling current to the second constant current control module (104), wherein the first preset multiple is greater than the second preset multiple. In a possible implementation of the first aspect, the current sampling unit (1021) comprises a first resistor and a second resistor, a first end of the first resistor and a first end of the second resistor are electrically connected with the first differential amplification unit (1022) and the second differential amplification unit (1023) respectively, the first end of the first resistor and the first end of the second resistor are configured to be electrically connected with the LED light source module (20), and a second end of the first resistor and a second end of the second resistor are grounded. In a possible implementation manner of the first aspect, the first differential amplification unit (1022) comprises a first operational amplifier, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor, a non-inverting input terminal of the first operational amplifier is electrically connected with a second terminal of the fourth resistor and a first terminal of the fifth resistor respectively, an inverting input terminal of the first operational amplifier is electrically connected with a second terminal of the third resistor and a first terminal of the sixth resistor respectively, an output terminal of the first operational amplifier is electrically connected with a second terminal of the sixth resistor and the first constant current control module (103) respectively, the first terminal of the third resistor and the second terminal of the fifth resistor are grounded, and a first terminal of the fourth resistor is electrically connected with the current sampling unit (1021). In a possible implementation manner of the first aspect, the second differential amplification unit (1023) comprises a second operational amplifier, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor, a non-inverting input terminal of the second operational amplifier is electrically connected with a second terminal of the eighth resistor and a first terminal of the ninth resistor respectively, an inverting input terminal of the second operational amplifier is electrically connected with a second terminal of the seventh resistor and a first terminal of the tenth resistor respectively, an output terminal of the second operational amplifier is electrically connected with a second terminal of the tenth resistor and the second constant current control module (104) respectively, the first terminal of the seventh resistor and the second terminal of the ninth resistor are grounded, and a first terminal of the eighth resistor is electrically connected with the current sampling unit (1021). In a possible implementation manner of the first aspect, the first constant current control module (103) comprises a third operational amplifier, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a first capacitor and a second capacitor, a first terminal of the eleventh resistor is configured to receive the first dimming signal, a second terminal of the eleventh resistor is electrically connected with a first terminal of the first capacitor and a first terminal of the twelfth resistor respectively, a first terminal of the thirteenth resistor is electrically connected with a first terminal of the second capacitor and a second terminal of the twelfth resistor respectively, a second terminal of the thirteenth resistor is electrically connected with an inverting input terminal of the third operational amplifier, a non-inverting input terminal of the third operational amplifier is electrically connected with a second terminal of the fourteenth resistor and a first terminal of the fifteenth resistor respectively, an output terminal of the third operational amplifier is electrically connected with the adjustment module (105), a second terminal of the first capacitor and a second terminal of the second capacitor are grounded, a first terminal of the fourteenth resistor is electrically connected with the current sampling module (102), and a second terminal of the fifteenth resistor is configured to be electrically connected with a first power supply. In a possible implementation manner of the first aspect, the second constant current control module (104) comprises a fourth operational amplifier, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a third capacitor and a fourth capacitor, a first end of the sixteenth resistor is configured to receive the second dimming signal, a second end of the sixteenth resistor is electrically connected with a first end of the third capacitor and a first end of the seventeenth resistor respectively, a first end of the eighteenth resistor is electrically connected with a first end of the fourth capacitor and a second end of the seventeenth resistor respectively, a second end of the eighteenth resistor is electrically connected with an inverting input end of the fourth operational amplifier, a non-inverting input end of the fourth operational amplifier is electrically connected with a second end of the nineteenth resistor and a first end of the twentieth resistor respectively, an output end of the fourth operational amplifier is electrically connected with the adjusting module (105), a second end of the third capacitor and a second end of the fourth capacitor are grounded, a first end of the nineteenth resistor is electrically connected with the current sampling module (102), and a second end of the twentieth resistor is configured to be electrically connected with a second power supply. In a possible implementation manner of the first aspect, the adjusting module (105) comprises a first diode, a second diode, a twenty-first resistor, a twenty-second resistor and a twenty-third resistor, an anode of the first diode is electrically connected with the second constant current control module (104) and a first end of the twenty-first resistor respectively, a cathode of the first diode is electrically connected with the first constant current control module (103), a first end of the twenty-second resistor is electrically connected with a second end of the twenty-first resistor, a second end of the twenty-second resistor is electrically connected with a first end of the twenty-third resistor, an anode of the second diode is electrically connected with a second end of the twenty-third resistor, and a cathode of the second diode is electrically connected with the voltage conversion module (101).

[0005] In a possible implementation manner of the first aspect, the voltage conversion module (101) comprises a voltage conversion chip, an enable pin of the voltage conversion chip is configured to receive an enable signal, an input pin of the voltage conversion chip is configured to receive an input voltage, a feedback pin of the voltage conversion chip is electrically connected with the adjusting module (105) and configured to receive the feedback voltage, and an output pin of the voltage conversion chip is configured to be electrically connected with the LED light source module (20). In the second aspect, the embodiments of the present application provide a constant current control device, comprising the constant current control circuit in any one of the first aspect.

[0006] Compared with the prior art, the embodiments of the present application have the following beneficial effects: The constant current control circuit provided in the embodiments of the present application comprises a voltage conversion module, a current sampling module, a first constant current control module, a second constant current control module and an adjusting module. The current sampling module collects a first current flowing through an LED light source module, and outputs a first sampling current to the first constant current control module and a second sampling current to the second constant current control module according to the first current.

[0007] The first constant current control module outputs a first control signal to the adjusting module according to the first sampling current and a received first dimming signal, and the adjusting module adjusts a feedback voltage according to the first control signal. Since the power supply voltage of the LED light source module output by the voltage conversion module is affected by the feedback voltage, the change of the feedback voltage drives the change of the power supply voltage, and then causes the first current flowing through the LED light source module to change correspondingly; the current sampling module collects the changed first current and outputs a new first sampling current, and the first constant current control module adjusts the output of the first control signal based on the updated first sampling current, so as to make the adjusting module continuously correct the feedback voltage, thereby forming a complete closed-loop constant current control loop.

[0008] The second constant current control module outputs a second control signal to the adjusting module according to the second sampling current and a received second dimming signal, and the adjusting module adjusts the feedback voltage according to the second control signal. Similarly, the change of the feedback voltage drives the change of the power supply voltage, and then causes the first current flowing through the LED light source module to change correspondingly; the current sampling module collects the changed first current and outputs a new second sampling current, and the second constant current control module adjusts the output of the second control signal based on the updated second sampling current, so as to make the adjusting module continuously correct the feedback voltage, thereby forming a complete closed-loop constant current control loop.

[0009] Therefore, the constant current control circuit provided in the embodiments of the present application innovatively adopts a two-stage constant current control architecture with independent closed loops, can construct two complete closed-loop constant current control loops, and respectively realizes the differentiated regulation of different currents, thereby breaking through the current regulation range limitation of the existing scheme, greatly improving the range coverage capability of current regulation, and then being able to fully meet the use demand of wide-range brightness regulation. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0011] Figure 1 is a principle block diagram of the constant current control circuit provided in an embodiment of the present application; Figure 2 is a principle block diagram of a constant current control circuit provided by another embodiment of the present application; Figure 3 is a circuit connection schematic diagram of a current sampling unit provided by an embodiment of the present application; Figure 4 is a circuit connection schematic diagram of a first differential amplification unit provided by an embodiment of the present application; Figure 5 is a circuit connection schematic diagram of a second differential amplification unit provided by an embodiment of the present application; Figure 6 is a circuit connection schematic diagram of a first constant current control module provided by an embodiment of the present application; Figure 7 is a circuit connection schematic diagram of a second constant current control module provided by an embodiment of the present application; Figure 8 is a circuit connection schematic diagram of an adjustment module provided by an embodiment of the present application; Figure 9 is a circuit connection schematic diagram of a voltage conversion module provided by an embodiment of the present application; Figure 10 is an MCU control signal schematic diagram provided by an embodiment of the present application.

[0012] In the figure, 10, constant current control circuit; 101, voltage conversion module; 102, current sampling module; 1021, current sampling unit; 1022, first differential amplification unit; 1023, second differential amplification unit; 103, first constant current control module; 104, second constant current control module; 105, adjustment module; 20, LED light source module. DETAILED DESCRIPTION

[0013] In the following description, specific details are set forth such as particular system configurations, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. However, persons skilled in the art will understand that the present application can be practiced without these specific details. In other instances, well-known structures, devices, circuits, and methods have not been described in detail in order to avoid obscuring the present application.

[0014] It should be understood that the term "comprising" as used in the specification and in the claims indicates the presence of the recited features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0015] It should also be understood that the term "and / or" as used herein refers to any one of the associated listed items, or a combination of any and all of the associated listed items, and includes all possible combinations thereof.

[0016] As used in the description of the application and the appended claims, the term "if" can be interpreted to mean "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [a described condition or event] is detected" can be interpreted to mean "upon determining" or "in response to determining" or "upon detecting [the described condition or event]" or "in response to detecting [the described condition or event]," depending on the context.

[0017] In addition, in the description of the application and the appended claims, the terms "first", "second", "third", etc. are used only to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0018] Reference in the specification to "one embodiment" or "some embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase "in one embodiment" or "in some embodiments" in various places in the specification are not necessarily all referring to the same embodiment, although it can. The terms "including," "comprising," "having" and variations thereof are meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0019] In order to illustrate the technical solutions described in the application, the following will be described by specific embodiments.

[0020] Figure 1 A principle block diagram of a constant current control circuit 10 provided by an embodiment of the application is shown. Referring to Figure 1 As shown, the constant current control circuit 10 includes a voltage conversion module 101, a current sampling module 102, a first constant current control module 103, a second constant current control module 104, and an adjustment module 105.

[0021] Specifically, the voltage conversion module 101 is configured to output a power supply voltage (LED+) to the LED light source module 20 to supply power to the LED light source module 20. In this power supply state, a current will flow through the LED light source module 20. The current sampling module 102 collects a first current flowing through the LED light source module 20, and outputs a first sampling current Imin to the first constant current control module 103 and a second sampling current Imax to the second constant current control module 104 according to the first current.

[0022] The first constant current control module 103 outputs a first control signal to the adjusting module 105 according to the first sampling current Imin and the received first dimming signal PWM_Min, and the adjusting module 105 adjusts the feedback voltage FB according to the first control signal. Since the power supply voltage of the LED light source module 20 output by the voltage conversion module 101 is affected by the feedback voltage FB, the change of the feedback voltage FB drives the change of the power supply voltage, and then the first current flowing through the LED light source module 20 changes accordingly; the current sampling module 102 collects the changed first current and outputs a new first sampling current Imin, and the first constant current control module 103 adjusts the output of the first control signal based on the updated first sampling current Imin, so as to continuously correct the feedback voltage FB by the adjusting module 105, thereby forming a complete closed-loop constant current control loop.

[0023] The second constant current control module 104 outputs a second control signal to the adjusting module 105 according to the second sampling current Imax and the received second dimming signal PWM_Max, and the adjusting module 105 adjusts the feedback voltage FB according to the second control signal. Similarly, the change of the feedback voltage FB drives the change of the power supply voltage, and then the first current flowing through the LED light source module 20 changes accordingly; the current sampling module 102 collects the changed first current and outputs a new second sampling current Imax, and the second constant current control module 104 adjusts the output of the second control signal based on the updated second sampling current Imax, so as to continuously correct the feedback voltage FB by the adjusting module 105, thereby forming a complete closed-loop constant current control loop.

[0024] Therefore, the constant current control circuit 10 provided by the embodiment of the present application innovatively adopts a two-stage constant current control architecture with independent closed loops, two complete closed-loop constant current control loops can be constructed, and the difference of different currents can be realized, which breaks through the current regulation range limitation of the existing scheme, greatly improves the range coverage capability of current regulation, and then can fully meet the use demand of wide range brightness adjustment.

[0025] It should be noted that the preset brightness threshold of the LED light source module 20 can be preset, and if the actual brightness of the LED light source module 20 is lower than the preset brightness threshold (i.e. low brightness working condition), the first constant current control module 103 starts to work and outputs the first control signal, the adjusting module 105 adjusts the feedback voltage FB according to the first control signal, and finally forms a closed-loop constant current control loop for small current, so as to stably output the current adapted to the low brightness demand. In this process, the second constant current control module 104 is in an open loop state and does not interfere with the closed-loop control dominated by the first constant current control module 103.

[0026] With the increasing demand for brightness adjustment of the LED light source module 20, when the duty cycle of the first dimming signal PWM_Min reaches 100%, the brightness of the LED light source module 20 increases to reach the preset brightness threshold (i.e. high brightness working condition), at this time, the second constant current control module 104 starts to work and outputs the second control signal, and the adjustment module 105 adjusts the feedback voltage FB according to the second control signal, and finally forms a closed-loop constant current control loop for large current. In this process, the first constant current control module 103 is in an open-loop state and does not interfere with the closed-loop control dominated by the second constant current control module 104.

[0027] Therefore, the constant current control circuit 10 provided by the embodiment of the present application not only innovatively adopts a two-stage constant current control architecture, but also divides the low brightness working condition and the high brightness working condition by setting the switching threshold brightness, and realizes the mutual exclusive independent work of the two-stage control modules. Among them, the first constant current control module 103 configured for the low brightness working condition can realize high-precision regulation and control of small current, not only greatly reduces the dimming starting point, but also stably covers the extremely low current interval, perfectly adapts to the low-light scene such as night scene light supplement, precision instrument indicator light, low-light environment monitoring and other scenes with high brightness precision requirements, effectively expands the application range of the circuit, and solves the technical pain point of large dimming starting point (high minimum brightness value) in the existing scheme using a dedicated chip. The second constant current control module 104 dominates the high brightness working condition, which can ensure the stability and reliability of the large current output. At the same time, the two-stage control architecture can increase the number of adjustments in the low current interval, thereby significantly improving the fineness of brightness adjustment, making the LED brightness switching smoother and the light combination more accurate.

[0028] In addition, the mutual exclusive working mechanism of the two-stage constant current control module can avoid the signal interference and conflict problem caused by the simultaneous intervention of multiple loops, ensure the continuity and smoothness of the brightness during the switching between low and high intervals, avoid the brightness mutation or flashlight phenomenon in the switching process, and significantly improve the user experience.

[0029] In an embodiment of the present application, as shown in Figure 2 The current sampling module 102 includes a current sampling unit 1021, a first differential amplification unit 1022, and a second differential amplification unit 1023.

[0030] Specifically, the current sampling unit 1021 is configured to collect the first current flowing through the LED light source module 20, take the collected first current as a basic sampling signal, and convert it into a second current (CS+ and CS-), which is transmitted to the first differential amplification unit 1022 and the second differential amplification unit 1023, respectively, to provide original signal support for subsequent current amplification and regulation.

[0031] The first differential amplification unit 1022 is configured to receive the second current and then perform differential amplification processing on the second current according to a first preset multiple, to obtain a first sampling current Imin that is adapted to the regulation requirement of a low-brightness scene, and transmit the first sampling current Imin to the first constant current control module 103, to provide a precise current feedback signal for closed-loop constant current control of the small-current loop.

[0032] The second differential amplification unit 1023 is configured to receive the second current and then perform differential amplification processing on the second current according to a second preset multiple, to obtain a second sampling current Imax that is adapted to the regulation requirement of a high-brightness scene, and transmit the second sampling current Imax to the second constant current control module 104, to provide a precise current feedback signal for closed-loop constant current control of the large-current loop. The first preset multiple is greater than the second preset multiple, to realize differentiated and precise amplification in different current intervals.

[0033] For example, the first preset multiple can be set to 590, and through the high-multiple differential amplification processing, the second current output by the current sampling unit 1021 can be precisely amplified by 590 times to obtain the first sampling current Imin that is adapted to the regulation of a low-brightness scene, to provide a sensitive and precise current feedback for closed-loop constant current control of the small-current loop. Correspondingly, the second preset multiple can be set to 10, and through the amplification multiple that is adapted to a large-current scene, the second current can be amplified by 10 times to obtain the second sampling current Imax, to meet the stable regulation requirement of the large-current loop in a high-brightness scene, and to ensure that the two control loops respectively realize efficient and precise feedback and regulation for different current ranges.

[0034] The working principle of the constant current control circuit 10 provided in the embodiments of the present application will be described in detail below with reference to the circuit schematic diagram shown in the accompanying drawings. Figures 3 to 10

[0035] In one embodiment of the present application, as shown in Figure 3 The current sampling unit 1021 includes a first resistor R1 and a second resistor R2, a first end of the first resistor R1 and a first end of the second resistor R2 are respectively electrically connected to the first differential amplification unit 1022 and the second differential amplification unit 1023, the first end of the first resistor R1 and the first end of the second resistor R2 are configured to be electrically connected to the LED light source module 20, and the second end of the first resistor R1 and the second end of the second resistor R2 are grounded. ​Specifically, the first resistor R1 and the second resistor R2 are both current sampling resistors, the first ends of the two are commonly connected with the LED light source module 20, and are synchronously connected with the first differential amplification unit 1022 and the second differential amplification unit 1023. When the current flows through the LED light source module 20, it will pass through the two resistors at the same time and generate a voltage signal (second current) corresponding to the size of the current flowing through the LED at both ends, which is synchronously transmitted to the first differential amplification unit 1022 and the second differential amplification unit 1023, thereby providing a basis for subsequent differential amplification processing of different multiples.

[0036] In an embodiment of the present application, as shown in Figure 4 The first differential amplification unit 1022 includes a first operational amplifier U1, a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6. The non-inverting input terminal (+IN) of the first operational amplifier U1 is connected with the second end of the fourth resistor R4 and the first end of the fifth resistor R5, respectively. The inverting input terminal (-IN) of the first operational amplifier U1 is connected with the second end of the third resistor R3 and the first end of the sixth resistor R6, respectively. The output terminal (OUT) of the first operational amplifier U1 is connected with the second end of the sixth resistor R6 and the first constant current control module 103, respectively. The first end of the third resistor R3 and the second end of the fifth resistor R5 are both grounded. The first end of the fourth resistor R4 is connected with the current sampling unit 1021. The power supply terminal (+Vs) of the first operational amplifier U1 is connected with a +5V power supply. The ground terminal (-Vs) of the first operational amplifier U1 is grounded.

[0037] Specifically, the first operational amplifier U1 in the first differential amplification unit 1022 is used as a core amplifier, which can realize differential signal amplification and signal conditioning. The third resistor R3 and the fifth resistor R5 are both grounded bias resistors, which provide stable static working points for the inverting input terminal and the non-inverting input terminal of the first operational amplifier U1, thereby avoiding the influence of input signal drift on amplification accuracy. The fourth resistor R4 is used as a signal input resistor, which is used to receive the second current and convert the second current into a voltage signal transmitted to the non-inverting input terminal of the first operational amplifier U1, thereby realizing effective import of the sampling signal. The sixth resistor R6 is used as a feedback resistor, which is connected between the output terminal and the inverting input terminal of the first operational amplifier U1, and cooperates with the fourth resistor R4 and the third resistor R3 to form a differential amplification loop. The resistance value of the sixth resistor R6 is determined according to the amplification multiple (i.e. the first preset multiple) of the first differential amplification unit 1022, so that the first operational amplifier U1 outputs the first sampling current Imin after accurate amplification, and transmits the first sampling current Imin to the first constant current control module 103.

[0038] For example, the designer can select the resistance values of the third resistor R3, the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6 according to actual conditions. For example, the resistance values of the third resistor R3 and the fourth resistor R4 can be selected as 1kΩ, and the resistance values of the fifth resistor R5 and the sixth resistor R6 can be selected as 590kΩ. Through this set of resistance ratio, the first preset amplification multiple of the first differential amplification unit 1022 can accurately reach 590 times, thereby meeting the high amplification and accurate feedback requirements of the tiny current under the low brightness working condition.

[0039] It should be noted that the first differential amplification unit 1022 further includes C5, C6, C7, C8 and R24, and the connection relationship can be referred to Figure 4 As shown in the figure, C5 is connected between the non-inverting input terminal and the inverting input terminal of the first operational amplifier U1, which can filter out high-frequency interference and common-mode noise in the input signal, improve the signal purity of differential amplification, and avoid the influence of spurious on the accuracy of current sampling; C6 and C7 are power filter capacitors, which can filter out high-frequency ripple and interference signals in the +5V power supply, provide stable and clean working power for the first operational amplifier U1, and ensure the stability and consistency of the operational amplifier amplification performance; C8 and R24 are connected in series and connected across the output terminal and the inverting input terminal of the first operational amplifier U1, forming an RC phase compensation network, which can suppress the self-oscillation that may occur during the operation of the operational amplifier, optimize the phase characteristics of the amplification circuit, improve the stability and response speed of the closed-loop negative feedback, and ensure that the first differential amplification unit 1022 can still output stable and distortionless first sampling current Imin under high amplification (such as 590 times) working condition.

[0040] In an embodiment of the present application, as Figure 5 As shown in the figure, the second differential amplification unit 1023 includes a second operational amplifier U2, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a tenth resistor R10. The non-inverting input terminal (+IN) of the second operational amplifier U2 is electrically connected to the second end of the eighth resistor R8 and the first end of the ninth resistor R9, respectively. The inverting input terminal (-IN) of the second operational amplifier U2 is electrically connected to the second end of the seventh resistor R7 and the first end of the tenth resistor R10, respectively. The output terminal (OUT) of the second operational amplifier U2 is electrically connected to the second end of the tenth resistor R10 and the second constant current control module 104, respectively. The first end of the seventh resistor R7 and the second end of the ninth resistor R9 are both grounded. The first end of the eighth resistor R8 is electrically connected to the current sampling unit 1021. The power supply end (+Vs) of the second operational amplifier U2 is used to connect the +5V power supply, and the ground end (-Vs) of the second operational amplifier U2 is grounded.

[0041] Specifically, the second operational amplifier U2 in the second differential amplification unit 1023 can realize differential signal amplification and signal conditioning as a core amplifier; the seventh resistor R7 and the ninth resistor R9 are both ground bias resistors, which provide a stable static working point for the inverting input terminal and the non-inverting input terminal of the second operational amplifier U2, so as to avoid the influence of input signal drift on the amplification accuracy; the eighth resistor R8 is a signal input resistor, which is used to receive the second current and convert the second current into a voltage signal transmitted to the non-inverting input terminal of the second operational amplifier U2, so as to realize effective import of the sampling signal; and the tenth resistor R10 is a feedback resistor, which is connected between the output terminal and the inverting input terminal of the second operational amplifier U2, and cooperates with the eighth resistor R8 and the seventh resistor R7 to form a differential amplification loop, so as to determine the amplification multiple (i.e., the second preset multiple) of the second differential amplification unit 1023 through resistance value matching, and finally make the output terminal of the second operational amplifier U2 output the second sampling current Imax after accurate amplification and transmit the second sampling current Imax to the second constant current control module 104.

[0042] For example, the designer can select the resistance values of the seventh resistor R7, the eighth resistor R8, the ninth resistor R9 and the tenth resistor R10 according to the actual situation, for example, the resistance values of the seventh resistor R7 and the eighth resistor R8 can be both 1kΩ, and the resistance values of the ninth resistor R9 and the tenth resistor R10 can be both 10kΩ. Through this set of resistance value matching, the second preset amplification multiple of the second differential amplification unit 1023 can accurately reach 10 times, so as to meet the low-multiple amplification and accurate feedback requirements of large current under high-brightness working conditions.

[0043] It should be noted that the second differential amplification unit 1023 also includes C9, C10, C11, C12 and R25, and the connection relationship can be referred to Figure 5 C9 is connected between the non-inverting input terminal and the inverting input terminal of the second operational amplifier U2, which can filter out high-frequency interference and common-mode noise in the input signal, improve the signal purity of differential amplification, and avoid the influence of spurious on the accuracy of current sampling; C10 and C11 are power filter capacitors, which can filter out high-frequency ripple and interference signals in the +5V power supply, provide a stable and clean working power supply for the second operational amplifier U2, and ensure the stability and consistency of the operational amplifier amplification performance; C12 and R25 are connected in series and connected between the output terminal and the inverting input terminal of the second operational amplifier U2, which form an RC phase compensation network, can suppress the self-oscillation that may occur during the operation of the operational amplifier, optimize the phase characteristics of the amplification circuit, improve the stability and response speed of the closed-loop negative feedback, and ensure that the second differential amplification unit 1023 can still output a stable and distortionless second sampling current Imax under low-multiple amplification (such as 10 times) working conditions.

[0044] In an embodiment of the present application, as Figure 6As shown, the first constant current control module 103 includes a third operational amplifier U3, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a first capacitor C1 and a second capacitor C2, a first end of the eleventh resistor R11 is configured to receive the first dimming signal PWM_Min, a second end of the eleventh resistor R11 is electrically connected with a first end of the first capacitor C1 and a first end of the twelfth resistor R12 respectively, a first end of the thirteenth resistor R13 is electrically connected with a first end of the second capacitor C2 and a second end of the twelfth resistor R12 respectively, a second end of the thirteenth resistor R13 is electrically connected with an inverting input end (-IN) of the third operational amplifier U3, a non-inverting input end (+IN) of the third operational amplifier U3 is electrically connected with a second end of the fourteenth resistor R14 and a first end of the fifteenth resistor R15 respectively, an output end (OUT) of the third operational amplifier U3 is electrically connected with the adjusting module 105, a second end of the first capacitor C1 and a second end of the second capacitor C2 are grounded, a first end of the fourteenth resistor R14 is electrically connected with the current sampling module 102, and a second end of the fifteenth resistor R15 is configured to be electrically connected with the first power supply. A power supply end (+Vs) of the third operational amplifier U3 is configured to be electrically connected with a +5V power supply, and a ground end (-Vs) of the third operational amplifier U3 is grounded.

[0045] Specifically, the eleventh resistor R11, the first capacitor C1, the twelfth resistor R12 and the second capacitor C2 together constitute a two-stage RC filter circuit, wherein the eleventh resistor R11 and the first capacitor C1 are a first-stage filter, the twelfth resistor R12 and the second capacitor C2 are a second-stage filter, which are configured to perform step-by-step filtering processing on the input first dimming signal PWM_Min, filter out high-frequency ripples and interference in the signal, and output a smooth first dimming signal PWM_Min, so as to avoid the influence of high-frequency noise on the control precision; the thirteenth resistor R13 is used as a feedback and signal transmission resistor, configured to receive the smooth first dimming signal PWM_Min after two-stage RC filtering, and accurately transmit the first dimming signal PWM_Min to the inverting input end of the third operational amplifier U3, so as to realize effective import of the first dimming signal PWM_Min; the fourteenth resistor R14 is used as a sampling signal input resistor, configured to receive the first sampling current Imin amplified by the first differential amplification unit 1022, and transmit the feedback signal of the first sampling current Imin to the non-inverting input end of the third operational amplifier U3 in combination with the fifteenth resistor R15, so as to provide a current feedback basis for the third operational amplifier U3. Finally, the third operational amplifier U3 compares the voltages at the inverting input end and the non-inverting input end, and outputs a corresponding control signal to the adjusting module 105, so as to drive the adjusting module 105 to adjust the feedback voltage FB of the voltage conversion module 101, and then realize closed-loop constant current precise control in a small current range.

[0046] For example, the first power supply can be a +5V power supply.

[0047] It should be noted that the first constant current control module 103 further includes C13, C14, C15, C16, C17 and R26, R27, and the connection relationship can be referred to Figure 6 As shown, C13 and C14 are power filter capacitors, which can filter high-frequency ripples and interference signals in the +5V power supply, provide stable and clean working power for the third operational amplifier U3, and ensure the stability and consistency of the operational amplifier amplification performance; C15 and R26 are connected in series and then connected across the output terminal and the inverting input terminal of the third operational amplifier U3, forming an RC phase compensation network, which can suppress self-oscillation that may occur during operation of the operational amplifier, optimize the phase characteristics of the amplification circuit, improve the stability and response speed of the closed-loop negative feedback, and ensure the output stability of the third operational amplifier U3; C16 is connected across the output terminal and the inverting input terminal of the third operational amplifier U3, which can further filter high-frequency noise and signal spikes, smooth the feedback signal waveform, reduce the influence of signal fluctuation on control accuracy, and assist in improving the stability of closed-loop control; C17 is connected between the non-inverting input terminal of the third operational amplifier U3 and the ground, and is used as a filter capacitor for the non-inverting input terminal, which can filter low-frequency interference and residual noise in the non-inverting input terminal current feedback signal, ensure the purity of the input signal, avoid the comparison reference of the third operational amplifier U3 from being offset by noise, and ensure the accuracy of small current regulation; R27 is connected to the output terminal of the third operational amplifier U3 and is used as an output current limiting resistor, which can limit the current size of the third operational amplifier U3 output to the adjustment module 105, avoid excessive current impact on the subsequent adjustment module 105, and at the same time play a role in buffering signals, optimize the transmission characteristics of the first control signal, and ensure the reliability of the two-stage constant current control loop switching and operation.

[0048] In an embodiment of the present application, as Figure 7As shown, the second constant current control module 104 includes a fourth operational amplifier U4, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a third capacitor C3 and a fourth capacitor C4, a first end of the sixteenth resistor R16 is configured to receive the second dimming signal PWM Max, a second end of the sixteenth resistor R16 is electrically connected with a first end of the third capacitor C3 and a first end of the seventeenth resistor R17 respectively, a first end of the eighteenth resistor R18 is electrically connected with a first end of the fourth capacitor C4 and a second end of the seventeenth resistor R17 respectively, a second end of the eighteenth resistor R18 is electrically connected with an inverting input end (-IN) of the fourth operational amplifier U4, a non-inverting input end (+IN) of the fourth operational amplifier U4 is electrically connected with a second end of the nineteenth resistor R19 and a first end of the twentieth resistor R20 respectively, an output end (OUT) of the fourth operational amplifier U4 is electrically connected with the adjusting module 105, a second end of the third capacitor C3 and a second end of the fourth capacitor C4 are grounded, a first end of the nineteenth resistor R19 is electrically connected with the current sampling module 102, and a second end of the twentieth resistor R20 is configured to be electrically connected with the second power supply. A power supply end (+Vs) of the fourth operational amplifier U4 is configured to be connected with a +5V power supply, and a ground end (-Vs) of the fourth operational amplifier U4 is grounded.

[0049] Specifically, the sixteenth resistor R16, the third capacitor C3, the seventeenth resistor R17 and the fourth capacitor C4 together constitute a two-stage RC filter circuit, wherein the sixteenth resistor R16 and the third capacitor C3 are a first-stage filter, the seventeenth resistor R17 and the fourth capacitor C4 are a second-stage filter, which is configured to perform step-by-step filtering processing on the input second dimming signal PWM Max, filter out high-frequency ripples and interference in the signal, and output a smooth second dimming signal PWM Max, so as to avoid the influence of high-frequency noise on the control accuracy; the eighteenth resistor R18 is used as a feedback and signal transmission resistor, configured to receive the smooth second dimming signal PWM Max after two-stage RC filtering, and accurately transmit the signal to the inverting input end of the fourth operational amplifier U4, so as to realize effective import of the second dimming signal PWM Max; the nineteenth resistor R19 is used as a sampling signal input resistor, configured to receive the second sampling current Imax amplified by the second differential amplification unit 1023, and transmit the feedback signal of the second sampling current Imax to the non-inverting input end of the fourth operational amplifier U4 in combination with the twentieth resistor R20, so as to provide a current feedback basis for the fourth operational amplifier U4. Finally, the fourth operational amplifier U4 compares the voltages at the inverting input end and the non-inverting input end, and outputs a corresponding control signal to the adjusting module 105, so as to drive the adjusting module 105 to adjust the feedback voltage FB of the voltage conversion module 101, and thus realize closed-loop constant current precise control in a large current range.

[0050] For example, the second power supply can be a +5V power supply.

[0051] It should be noted that the second constant current control module 104 further includes C18, C19, C20, C21, C22 and R28, R29, and the connection relationship can be referred to Figure 7 As shown in the figure, C18 and C19 are power filter capacitors, which can filter out high-frequency ripples and interference signals in the +5V power supply, provide stable and clean working power for the fourth operational amplifier U4, and ensure the stability and consistency of the operational amplifier amplification performance; C20 and R28 are connected in series and then connected across the output terminal and the inverting input terminal of the fourth operational amplifier U4, forming an RC phase compensation network, which can suppress the self-oscillation that may occur during the operation of the operational amplifier, optimize the phase characteristics of the amplification circuit, improve the stability and response speed of the closed-loop negative feedback, and ensure the output stability of the fourth operational amplifier U4; C21 is connected across the output terminal and the inverting input terminal of the fourth operational amplifier U4, which can further filter out high-frequency noise and signal spikes, smooth the feedback signal waveform, reduce the influence of signal fluctuation on control accuracy, and assist in improving the stability of closed-loop control; C22 is connected between the non-inverting input terminal of the fourth operational amplifier U4 and the ground, acting as a filter capacitor for the non-inverting input terminal, which can filter out low-frequency interference and residual noise in the non-inverting input terminal current feedback signal, ensure the purity of the input signal, avoid the offset of the fourth operational amplifier U4 comparison reference caused by noise, and ensure the accuracy of large current regulation; R29 is connected to the output terminal of the fourth operational amplifier U4, acting as an output current limiting resistor, which can limit the current size of the fourth operational amplifier U4 output to the adjustment module 105, avoid excessive current impact on the subsequent adjustment module 105, and at the same time play a role in buffering signals, optimize the transmission characteristics of the second control signal, and ensure the reliability of the two-stage constant current control loop switching and operation.

[0052] In an embodiment of the present application, as Figure 8 shown, the adjustment module 105 includes a first diode D1, a second diode D2, a twenty-first resistor R21, a twenty-second resistor R22 and a twenty-third resistor R23, the anode of the first diode D1 is respectively connected with the second constant current control module 104 and the first end of the twenty-first resistor R21, the cathode of the first diode D1 is connected with the first constant current control module 103, the first end of the twenty-second resistor R22 is connected with the second end of the twenty-first resistor R21, the second end of the twenty-second resistor R22 is connected with the first end of the twenty-third resistor R23, the anode of the second diode D2 is connected with the second end of the twenty-third resistor R23, and the cathode of the second diode D2 is connected with the voltage conversion module 101.

[0053] Specifically, the first diode D1 and the second diode D2 both play the role of one-way conduction and isolation, wherein the first diode D1 can realize one-way transmission and mutual exclusion isolation of the output signals of the first constant current control module 103 and the second constant current control module 104, avoid signal interference when the two-stage control module works, and guarantee the independence and stability when switching between low brightness and high brightness working conditions; the second diode D2 can prevent the feedback voltage FB of the voltage conversion module 101 from flowing back in reverse to the adjustment module 105, and protect the constant current control module from reverse voltage impact; the twenty-first resistor R21, the twenty-second resistor R22 and the twenty-third resistor R23 are all voltage dividing resistors, which are connected in series to form a signal transmission and voltage dividing circuit, can limit the current size output by the two-stage constant current control module to the voltage conversion module 101, avoid damage to the voltage conversion module 101 by excessive current, and further adjust the signal voltage amplitude transmitted to the voltage conversion module 101 by resistance ratio, so that the adjustment of the feedback voltage FB is more accurate, thereby realizing fine regulation and control of the output voltage of the voltage conversion module 101, and finally guaranteeing the stable output of the LED light source module 20 current, and achieving wide range and high precision brightness adjustment effect with the two-stage constant current control architecture.

[0054] It should be noted that the adjustment module 105 further includes C23 and C24, wherein C23 is connected at the rear end of the twenty-first resistor R21, can filter out high-frequency ripple and residual interference in the first control signal / second control signal, avoid the influence of the ripple on the adjustment accuracy of the feedback voltage FB, and guarantee the smoothness of signal transmission; C24 is connected at the rear end of the twenty-second resistor R22, can further filter the noise and signal fluctuation that may be introduced in the voltage dividing process, make the signal transmitted to the second diode D2 and the voltage conversion module 101 more pure and stable, assist to improve the accuracy of the feedback voltage FB adjustment, and further guarantee the stable output of the LED light source module 20 current and the smoothness of the two-stage brightness switching.

[0055] In an embodiment of the present application, as shown in Figure 9 the voltage conversion module 101 includes a voltage conversion chip, an enable pin of the voltage conversion chip is used to receive an enable signal EN, an input pin of the voltage conversion chip is used to receive an input voltage, a feedback pin of the voltage conversion chip is electrically connected with the adjustment module 105 and is used to receive a feedback voltage FB, and an output pin of the voltage conversion chip is used to be electrically connected with the LED light source module 20.

[0056] Specifically, the enable pin is used to control the start and stop of the voltage conversion chip, realizing the on-demand start and stop of circuit power supply; the input pin receives an external input voltage to provide a working power basis for the chip; the feedback pin senses the current change of the LED light source module 20 in real time by receiving the feedback voltage FB transmitted by the adjusting module 105, and then dynamically adjusts the output voltage of the voltage conversion chip (i.e. the power supply voltage of the LED light source module 20); the output pin is used to output a stable power supply voltage to power the LED light source module 20, and can accurately adjust the output voltage amplitude according to the change of the feedback voltage FB, and cooperates with the synergistic effect of the two-stage constant current control loop and the adjusting module 105 to realize wide-range and high-precision regulation and control of the current of the LED light source module 20, ensuring low-brightness micro-light output and high-brightness stable operation.

[0057] It should be noted that the voltage conversion chip shown in the embodiments of the present application is specifically a step-down chip, and the peripheral circuit thereof is a matching circuit device configured for the step-down chip. In actual application, a step-up chip or a step-up / down chip or other types of voltage conversion chips can also be selected according to the power supply requirements, as long as the selected chip can realize voltage conversion and output adjustment functions, and then stably provide working power for the LED light source module 20. Therefore, the specific configuration of the internal chip type and the chip peripheral circuit of the voltage conversion module 101 is not limited in the present application.

[0058] It should be noted that the enable signal EN, the first dimming signal PWM_Min and the second dimming signal PWM_Max described above can be provided by the MCU shown. Figure 10

[0059] It should be noted that, in order to overcome the defects of the prior art, such as low efficiency, high cost, large PCB (Printed Circuit Board) board space occupation, insufficient power density, etc. caused by the need to match a separate linear constant current dimming circuit or a special dimming chip after the DCDC output constant voltage, the constant current control circuit 10 is designed by an operational amplifier in the present application, which directly eliminates the additional linear constant current dimming circuit in the traditional scheme, thereby simplifying the circuit structure and effectively avoiding many drawbacks of the prior art.

[0060] The working principle of the constant current control circuit 10 will be described in detail below in combination with the circuit diagram.

[0061] When the power is first turned on, the output terminals of the third operational amplifier U3 and the fourth operational amplifier U4 both output 5V high level, which is transmitted through resistance and capacitance and diodes and then fed to the FB pin of the voltage conversion chip. At this time, the output voltage of the voltage conversion chip is the minimum value, which can be determined by resistance ratio calculation of the corresponding voltage dividing resistor.

[0062] ​When the brightness is low, the MCU outputs the first dimming signal PWM_Min (the duty cycle of the second dimming signal PWM_Max is 0%), which is transmitted to the inverting input terminal of the third operational amplifier U3 after RC filtering, so that the output terminal of the third operational amplifier U3 is lowered, and then the first diode D1 is turned on. After the first diode D1 is turned on, a part of the current is diverted, causing the anode voltage of the first diode D1 to decrease. This voltage is transmitted to the FB pin of the voltage conversion chip after subsequent resistance voltage division, causing the voltage of the FB pin to decrease, and then the output voltage of the voltage conversion chip to increase, thereby increasing the first current flowing through the LED light source module 20. After the first current passes through the sampling resistor (R1 and R2), it is amplified by 590 times by the first differential amplification unit 1022 and output to the non-inverting input terminal of the third operational amplifier U3, forming a closed-loop negative feedback with the first dimming signal PWM_Min at the inverting input terminal, ensuring accurate control in the small current range. In this process, since the non-inverting input terminal of the fourth operational amplifier U4 is not connected to the effective second dimming signal PWM_Max, the fourth operational amplifier U4 is in an open-loop state, continuously outputting a 5V high level, the large current control loop does not work, and will not affect the small current control loop.

[0063] When the brightness is high, the MCU outputs the second dimming signal PWM_Max (the duty cycle of the first dimming signal PWM_Min is 100%), which is transmitted to the inverting input terminal of the fourth operational amplifier U4 after RC filtering, so that the output terminal of the fourth operational amplifier U4 is lowered, and then transmitted to the FB pin of the voltage conversion chip after resistance voltage division, causing the voltage of the FB pin to decrease, and then the output voltage of the voltage conversion chip to increase, thereby increasing the first current flowing through the LED light source module 20. After the first current passes through the sampling resistor (R1 and R2), it is amplified by 10 times by the second differential amplification unit 1023 and output to the non-inverting input terminal of the fourth operational amplifier U4, forming a closed-loop negative feedback with the second dimming signal PWM_Max at the inverting input terminal, ensuring stable control in the large current range. In this process, since the non-inverting input terminal of the fourth operational amplifier U4 has a certain voltage value, the duty cycle of the second dimming signal PWM_Max needs to reach a preset value (such as 5%) before the fourth operational amplifier U4 can start working and output the second control signal; after subsequent adjustment, current sampling and amplification, the voltage at the non-inverting input terminal of the third operational amplifier U3 will be greater than the voltage at the inverting input terminal of the third operational amplifier U3, prompting the output terminal of the third operational amplifier U3 to output a high level, and the first diode D1 to be turned off. At this time, the small current control loop stops working, the third operational amplifier U3 is in an open-loop state, and will not affect the large current control loop.

[0064] In addition, the switching of the two-stage control loop needs to follow a specific logic: when switching from small current control to large current control, the duty cycle of the first dimming signal PWM_Min needs to be adjusted to 100%; when switching from large current control to small current control, the duty cycle of the second dimming signal PWM_Max needs to be adjusted to 0%. The small current control loop and the large current control loop are independent working units that do not interfere with each other. Through the above switching logic, smooth transition of the two-stage control can be achieved, and the phenomenon of flashing light during switching can be avoided.

[0065] For example, the first differential amplification unit 1022 differentially amplifies the second current output by the current sampling unit 1021 by a first preset multiple (590 times), so that the amplified output signal reaches 3V, and the current of the LED light source module 20 is 150mA, which meets the precise regulation and control requirement under low brightness conditions; the second differential amplification unit 1023 differentially amplifies the second current by a second preset multiple (10 times), so that the amplified output signal also reaches 3V, and the current of the LED light source module 20 is 8.8A, which meets the large current stable output requirement under high brightness conditions. Compared with the existing scheme that can only achieve a minimum current of about 1mA, the two-stage differential amplification design of the present application can optimize the minimum working current of the LED light source module 20 to the level of tens of μA, greatly reducing the dimming starting point and better adapting to the use requirement of the micro-light scene.

[0066] The present application also discloses a constant current control device comprising the above-mentioned constant current control circuit 10. The constant current control device can realize two-stage analog dimming and precise constant current control of the LED light source module 20 by integrating the above-mentioned constant current control circuit 10, which greatly reduces the dimming starting point, optimizes the minimum working current from about 1mA of the existing scheme to the level of tens of μA, meets the scene requirement of low brightness precision requirement such as night scene light supplement, precision instrument indication, and micro-light environment monitoring; and through the differential regulation and control of the large and small current two-stage independent closed loop, the control accuracy and the number of regulation parts in the low current interval are improved, and the stable output of the maximum 8.8A large current is realized, achieving wide-range and high-precision brightness adjustment effect, and making the light combination more accurate. At the same time, the device eliminates the linear constant current dimming circuit or special dimming chip in the traditional scheme, effectively improves the product power density and working efficiency, reduces the heat dissipation pressure, and reduces the overall cost and PCB layout space. Through the optimized switching logic, smooth transition of the large and small current loops is realized, the phenomenon of flashing light is avoided, and complex software control is not required, software resources are saved, and the product reliability and market competitiveness are significantly enhanced.

[0067] Since the processing and functions realized by the constant current control device in the embodiment are basically corresponding to the embodiments, principles and examples of the constant current control circuit, the description of the embodiment will not be described in detail, and the related description in the foregoing embodiments can be referred to, and will not be described herein.

[0068] The foregoing embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A constant current control circuit (10) characterized by, The application relates to a voltage conversion module (101), a current sampling module (102), a first constant current control module (103), a second constant current control module (104) and an adjusting module (105), wherein: The current sampling module (102) is used for collecting a first current flowing through the LED light source module (20) and is electrically connected with the first constant current control module (103) and the second constant current control module (104) respectively, the current sampling module (102) outputs a first sampling current to the first constant current control module (103) and a second sampling current to the second constant current control module (104) according to the first current; The first constant current control module (103) is used for receiving a first dimming signal and generating a first control signal based on the first sampling current and the first dimming signal; The second constant current control module (104) is used for receiving a second dimming signal and generating a second control signal based on the second sampling current and the second dimming signal; The adjusting module (105) is electrically connected with the voltage conversion module (101), the first constant current control module (103) and the second constant current control module (104) respectively, and the adjusting module (105) is used for adjusting a feedback voltage of the voltage conversion module (101) according to the first control signal or the second control signal.

2. The constant current control circuit (10) according to claim 1, characterized in that The current sampling module (102) comprises a current sampling unit (1021), a first differential amplification unit (1022) and a second differential amplification unit (1023), wherein: The current sampling unit (1021) is electrically connected with the first differential amplification unit (1022) and the second differential amplification unit (1023) respectively, and the current sampling unit (1021) is used for collecting a first current flowing through the LED light source module (20) and outputting a second current to the first differential amplification unit (1022) and the second differential amplification unit (1023) respectively; The first differential amplification unit (1022) is electrically connected with the first constant current control module (103), and the first differential amplification unit (1022) is used for amplifying the second current by a first preset multiple to obtain the first sampling current and transmitting the first sampling current to the first constant current control module (103); The second differential amplification unit (1023) is electrically connected with the second constant current control module (104), and the second differential amplification unit (1023) is used for amplifying the second current by a second preset multiple to obtain the second sampling current and transmitting the second sampling current to the second constant current control module (104), wherein the first preset multiple is greater than the second preset multiple.

3. The constant current control circuit (10) according to claim 2, characterized in that The current sampling unit (1021) comprises a first resistor and a second resistor, a first end of the first resistor and a first end of the second resistor are respectively electrically connected with the first differential amplification unit (1022) and the second differential amplification unit (1023), and the first end of the first resistor and the first end of the second resistor are used for being electrically connected with the LED light source module (20), and a second end of the first resistor and a second end of the second resistor are grounded.

4. The constant current control circuit (10) according to claim 2, characterized in that The first differential amplification unit (1022) comprises a first operational amplifier, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor, a non-inverting input terminal of the first operational amplifier is electrically connected with a second end of the fourth resistor and a first end of the fifth resistor, a inverting input terminal of the first operational amplifier is electrically connected with a second end of the third resistor and a first end of the sixth resistor, an output terminal of the first operational amplifier is electrically connected with a second end of the sixth resistor and the first constant current control module (103), a first end of the third resistor and a second end of the fifth resistor are grounded, and a first end of the fourth resistor is electrically connected with the current sampling unit (1021).

5. The constant current control circuit (10) according to claim 2, characterized in that The second differential amplification unit (1023) comprises a second operational amplifier, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor, a non-inverting input terminal of the second operational amplifier is electrically connected with a second end of the eighth resistor and a first end of the ninth resistor, a inverting input terminal of the second operational amplifier is electrically connected with a second end of the seventh resistor and a first end of the tenth resistor, an output terminal of the second operational amplifier is electrically connected with a second end of the tenth resistor and the second constant current control module (104), a first end of the seventh resistor and a second end of the ninth resistor are grounded, and a first end of the eighth resistor is electrically connected with the current sampling unit (1021).

6. The constant current control circuit (10) according to claim 1, characterized in that The first constant current control module (103) comprises a third operational amplifier, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a first capacitor and a second capacitor, a first end of the eleventh resistor is used for receiving the first dimming signal, a second end of the eleventh resistor is electrically connected with a first end of the first capacitor and a first end of the twelfth resistor, a first end of the thirteenth resistor is electrically connected with a first end of the second capacitor and a second end of the twelfth resistor, a second end of the thirteenth resistor is electrically connected with a inverting input terminal of the third operational amplifier, a non-inverting input terminal of the third operational amplifier is electrically connected with a second end of the fourteenth resistor and a first end of the fifteenth resistor, an output terminal of the third operational amplifier is electrically connected with the adjustment module (105), a second end of the first capacitor and a second end of the second capacitor are grounded, a first end of the fourteenth resistor is electrically connected with the current sampling module (102), and a second end of the fifteenth resistor is used for being electrically connected with a first power supply.

7. The constant current control circuit (10) according to claim 1, characterized in that The second constant current control module (104) comprises a fourth operational amplifier, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a third capacitor and a fourth capacitor, a first end of the sixteenth resistor is configured to receive the second dimming signal, a second end of the sixteenth resistor is electrically connected with a first end of the third capacitor and a first end of the seventeenth resistor respectively, a first end of the eighteenth resistor is electrically connected with a first end of the fourth capacitor and a second end of the seventeenth resistor respectively, a second end of the eighteenth resistor is electrically connected with an inverting input end of the fourth operational amplifier, a non-inverting input end of the fourth operational amplifier is electrically connected with a second end of the nineteenth resistor and a first end of the twentieth resistor respectively, an output end of the fourth operational amplifier is electrically connected with the adjusting module (105), a second end of the third capacitor and a second end of the fourth capacitor are grounded, a first end of the nineteenth resistor is electrically connected with the current sampling module (102), and a second end of the twentieth resistor is configured to be electrically connected with a second power supply.

8. The constant current control circuit (10) according to claim 1, characterized in that The adjusting module (105) comprises a first diode, a second diode, a twenty-first resistor, a twenty-second resistor and a twenty-third resistor, an anode of the first diode is electrically connected with the second constant current control module (104) and a first end of the twenty-first resistor respectively, a cathode of the first diode is electrically connected with the first constant current control module (103), a first end of the twenty-second resistor is electrically connected with a second end of the twenty-first resistor, a second end of the twenty-second resistor is electrically connected with a first end of the twenty-third resistor, an anode of the second diode is electrically connected with a second end of the twenty-third resistor, and a cathode of the second diode is electrically connected with the voltage conversion module (101).

9. Constant current control circuit (10) according to any one of claims 1 to 8, characterized in that The voltage conversion module (101) comprises a voltage conversion chip, an enable pin of the voltage conversion chip is configured to receive an enable signal, an input pin of the voltage conversion chip is configured to receive an input voltage, a feedback pin of the voltage conversion chip is electrically connected with the adjusting module (105) and configured to receive the feedback voltage, and an output pin of the voltage conversion chip is configured to be electrically connected with the LED light source module (20).

10. A constant current control device, characterized by, The constant current control circuit (10) comprises the constant current control circuit (10) according to any one of claims 1-9.

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