Electronic device and control circuit of breathing light thereof

Abstract

The application discloses an electronic device and a control circuit of a breathing lamp thereof. The control circuit comprises a controller, a waveform conversion circuit, a filter circuit and a control brightness circuit. The controller is configured to output a first control signal. The waveform conversion circuit is connected with an output end of the controller and configured to perform waveform conversion on the first control signal to obtain a second control signal. The filter circuit is connected with an output end of the waveform conversion circuit and configured to filter the second control signal. The control brightness circuit comprises a first switch tube, a bias resistor, a first resistor and an LED lamp. A control end of the first switch tube is connected with the output end of the filter circuit through the bias resistor, so that the first switch tube works in an amplification state based on the filtered second control signal. The brightness of the LED lamp changes with the voltage amplitude of the second control signal. The controller of the application does not need a PWM function, can realize smooth change of the brightness of the LED lamp and effectively improves the stability of the breathing lamp effect.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to an electronic device and a control circuit for its breathing light. Background Technology

[0002] Breathing lights, due to their gentle brightness changes, are widely used for status indication and ambiance creation in electronic devices. To achieve this smooth brightness variation, traditional breathing light control circuits typically use PWM (Pulse Width Modulation) duty cycle adjustment. However, this approach has limitations: firstly, traditional solutions require the GPIO (General-Purpose Input / Output) interface of the controller, such as an MCU (Microcontroller Unit), to have PWM functionality, restricting hardware selection flexibility; secondly, due to limitations in the PWM signal period and duty cycle adjustment range, it is difficult to achieve a long-cycle breathing effect, and the adjustment of the breathing cycle is not flexible enough. Utility Model Content

[0003] To solve the above-mentioned technical problems, this application provides a control circuit for a breathing light.

[0004] This application provides a control circuit for a breathing light, characterized in that it includes: The controller is used to output the first control signal; A waveform conversion circuit, connected to the output terminal of the controller, is used to convert the first control signal into a second control signal. A filtering circuit, connected to the output of the waveform conversion circuit, is used to filter the second control signal; A brightness control circuit includes a first switching transistor, a bias resistor, at least one first resistor, and at least one LED. The control terminal of the first switching transistor is connected to the output terminal of the filter circuit through the bias resistor. The first terminal of the first switching transistor is connected to the negative terminal of the LED through the corresponding first resistor. The positive terminal of the LED receives a reference voltage. The second terminal of the first switching transistor is grounded, so that the first switching transistor operates in an amplification state based on a filtered second control signal. The brightness of the LED follows the voltage change of the second control signal.

[0005] The control circuit further includes a conversion circuit, which is connected to the output terminal of the controller. The first output terminal of the conversion circuit is connected to the waveform conversion circuit to output the first control signal to the waveform conversion circuit.

[0006] The waveform conversion circuit includes a second resistor, a first capacitor, at least one second capacitor, at least one second switching transistor, and a first operational amplifier. One end of the second resistor is connected to the first output terminal of the conversion circuit, and the other end of the second resistor is connected to the first input terminal of the first operational amplifier. The second input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier. One end of the first capacitor is connected to the first input terminal of the first operational amplifier, and the other end of the first capacitor is grounded. One end of the second capacitor is connected to the first input terminal of the first operational amplifier, and the other end of the second capacitor is connected to the first terminal of the second switching transistor. The control terminal of the second switching transistor is connected to the second output terminal of the conversion circuit.

[0007] The controller is used to control the second switch to turn on, the at least one second capacitor is connected in parallel with the first capacitor, and the second resistor, the first capacitor and the at least one second capacitor form an RC filter circuit.

[0008] The controller is used to control the second switch to turn off, and the second resistor and the first capacitor form an RC filter circuit.

[0009] The filter circuit includes a third resistor, a third capacitor, and a second operational amplifier. The first input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier through the third resistor. The first input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier through the third capacitor. The second input terminal of the second operational amplifier is grounded. The output terminal of the second operational amplifier is connected to the control terminal of the first switching transistor.

[0010] The filter circuit further includes a third switch and a fourth resistor. The control terminal of the third switch is connected to the third output terminal of the conversion circuit, the first terminal of the third switch is connected to the first input terminal of the second operational amplifier, and the second terminal of the third switch is connected to the output terminal of the second operational amplifier through the fourth resistor.

[0011] The controller controls the third switch to turn on, and the third switch is used to amplify the voltage of the second control signal.

[0012] The resistance value of the bias resistor satisfies the following relationship: R5 ≥ ; Wherein, R5 is the resistance value of the bias resistor. The first output terminal of the conversion circuit outputs a high-level voltage. The voltage between the control terminal and the second terminal of the first switching transistor. The amplification factor of the first switching transistor is given. The resistance value of the at least one first resistor. The reference voltage, The voltage of the at least one LED lamp, The voltage between the first and second terminals of the first switching transistor is denoted as N, and N is the number of the at least one LED.

[0013] This application also provides an electronic device that controls the brightness change of the breathing light through the control circuit of the breathing light described above.

[0014] The beneficial effects of this application are as follows: The control circuit of the breathing light of this application includes a controller, a waveform conversion circuit, a filtering circuit, and a brightness control circuit. The controller is used to output a first control signal. The waveform conversion circuit is connected to the output terminal of the controller and is used to convert the first control signal into a second control signal. The filtering circuit is connected to the output terminal of the waveform conversion circuit and is used to filter the second control signal. The brightness control circuit includes a first switching transistor, a bias resistor, at least one first resistor, and at least one LED. The control terminal of the first switching transistor is connected to the output terminal of the filtering circuit through the bias resistor. The first terminal of the first switching transistor is connected to the negative terminal of the LED through the corresponding first resistor. The positive terminal of the LED receives a reference voltage. The second terminal of the first switching transistor is grounded, so that the first switching transistor operates in an amplification state based on the filtered second control signal, and the brightness of the LED follows the voltage change of the second control signal. The controller in this application does not need to have PWM function. It outputs a first control signal, which is then converted and filtered to generate a smoothly changing second control signal. This drives the first switching transistor to work in the amplification region, so that the brightness of the LED light follows the voltage amplitude of the second control signal. This can support a long-period and flexibly adjustable breathing light effect and improve the control accuracy of the breathing light brightness. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a circuit diagram of the first embodiment of the control circuit for the breathing light provided in this application.

[0016] Icon labels: Controller 10, Controller output terminal 11, Waveform conversion circuit 20, Waveform conversion circuit output terminal 21, First operational amplifier U1, First input terminal of first operational amplifier U1 22, Second input terminal of first operational amplifier U1 23, Output terminal of first operational amplifier U1 24, Second resistor R1, First capacitor C1, Second capacitor C2, Second switch Q2, Filter circuit 30, Filter circuit output terminal 31, Second operational amplifier U2, First input terminal of second operational amplifier U2 32, Second input terminal of second operational amplifier U2 33, Output terminal of second operational amplifier U2 34, Third resistor R2, Third capacitor C3, Third switch Q3, Fourth resistor R3, Fifth resistor R4, Brightness control circuit 40, LED lamp 41, Bias resistor R5, First resistor R LED First switching transistor Q1, reference voltage V DD 50. Conversion circuit; 51. First output terminal of conversion circuit; 52. Second output terminal of conversion circuit; 53. Third output terminal of conversion circuit. Detailed Implementation

[0017] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0019] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order, or primary and secondary relationship of the indicated technical features.

[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0022] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0023] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a connection between two components or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0024] This application provides a control circuit for a breathing light; please refer to [link / reference]. Figure 1 As shown. Figure 1 This is a circuit diagram of the first embodiment of the control circuit for the breathing light provided in this application.

[0025] According to some embodiments of this application, such as Figure 1 As shown, the control circuit of the breathing light in this embodiment includes a controller 10, a waveform conversion circuit 20, a filter circuit 30, and a brightness control circuit 40.

[0026] The controller 10 can be an MCU, and the MCU's GPIO interface does not need to have PWM functionality. The controller 10 is used to periodically output a high-level or low-level voltage to output a first control signal. The waveform conversion circuit 20 is connected to the output terminal 11 of the controller and is used to convert the first control signal into a second control signal.

[0027] The brightness control circuit 40 includes a first switching transistor Q1, a bias resistor R5, and at least one first resistor R. LED And at least one LED 41, the control terminal of the first switching transistor Q1 is connected to the output terminal 31 of the filter circuit through the bias resistor R5, and the first terminal of the first switching transistor Q1 is connected to the corresponding first resistor R LED The LED 41 is connected to its negative terminal, and its positive terminal receives a reference voltage V. DDThe second terminal of the first switching transistor Q1 is grounded so that the first switching transistor Q1 operates in the amplification state based on the filtered second control signal, and the brightness of the LED 41 follows the voltage change of the second control signal.

[0028] In this embodiment, by setting the resistance value of the bias resistor R5, the quiescent operating point of the first switching transistor Q1 falls within the amplification region of its output characteristic curve, thereby ensuring that the first switching transistor Q1 always operates in the amplification state. The first resistor R... LED Used to limit the maximum current flowing through LED 41, thus protecting LED 41. Reference voltage V DD Used to provide a stable operating power supply for LED lamp 41, and connected to the first resistor R LED Together, they limit the maximum current flowing through LED 41. The brightness of LED 41 is controlled by a second control signal, and the brightness of LED 41 changes with the voltage amplitude of the second control signal.

[0029] The control circuit of the breathing light in this embodiment includes a controller 10, a waveform conversion circuit 20, a filter circuit 30, and a brightness control circuit 40. The controller 10 outputs a first control signal. The waveform conversion circuit 20 is connected to the output terminal 11 of the controller and converts the first control signal into a second control signal. The filter circuit 30 is connected to the output terminal 21 of the waveform conversion circuit and filters the second control signal. The brightness control circuit 40 includes a first switching transistor Q1, a bias resistor R5, and at least one first resistor R. LED And at least one LED light 41, the control terminal of the first switch Q1 is connected to the corresponding first resistor R LED The first resistor R is connected to the negative terminal of LED 41. LED This is used to limit the current flowing through LED 41 to protect it. The positive terminal of LED 41 receives a reference voltage V. DD The second terminal of the first switch Q1 is grounded. The first switch Q1 operates in the amplification state based on the filtered second control signal, eliminating the need for the controller 10 to have PWM functionality, thereby achieving smooth brightness changes in the LED 41 and improving the stability of the breathing effect of the breathing light.

[0030] According to some embodiments of this application, such as Figure 1 As shown, the control circuit of the breathing light also includes a conversion circuit 50, which is connected to the output terminal 11 of the controller. The first output terminal 51 of the conversion circuit is connected to the waveform conversion circuit 20 to output a first control signal to the waveform conversion circuit 20.

[0031] Furthermore, the waveform conversion circuit 20 includes a second resistor R1, a first capacitor C1, at least one second capacitor C2, at least one second switch Q2, and a first operational amplifier U1. One end of the second resistor R1 is connected to the first output terminal 51 of the conversion circuit, and the other end of the second resistor R1 is connected to the first input terminal 22 of the first operational amplifier U1. The second input terminal 23 of the first operational amplifier U1 is connected to the output terminal 24 of the first operational amplifier U1. One end of the first capacitor C1 is connected to the first input terminal 22 of the first operational amplifier U1, and the other end of the first capacitor C1 is grounded. One end of the second capacitor C2 is connected to the first terminal of the second switch Q2, and the control terminal of the second switch Q2 is connected to the second output terminal 52 of the conversion circuit.

[0032] The conversion circuit 50 is used to expand the output terminal 11 of the controller. The first input terminal 22 of the first operational amplifier U1 is the non-inverting input terminal, the second input terminal 23 of the first operational amplifier U1 is the inverting input terminal, the output terminal 24 of the first operational amplifier U1 serves as the output terminal 21 of the waveform conversion circuit, and the second input terminal 23 of the first operational amplifier U1 is connected to the output terminal 24 of the first operational amplifier U1 to form a voltage follower, which is used to improve the stability of the second control signal during transmission.

[0033] The control circuit of this embodiment includes a conversion circuit 50. The waveform conversion circuit 20 includes a second resistor R1, a first capacitor C1, at least one second capacitor C2, at least one second switch Q2, and a first operational amplifier U1. One end of the second resistor R1 is connected to the first output terminal 51 of the conversion circuit, and the other end of the second resistor R1 is connected to the first input terminal 22 of the first operational amplifier U1. The second input terminal 23 of the first operational amplifier U1 is connected to the output terminal 24 of the first operational amplifier U1. One end of the first capacitor C1 is connected to the first input terminal 22 of the first operational amplifier U1, and the other end of the first capacitor C1 is grounded. One end of the second capacitor C2 is connected to the first terminal of the second switch Q2, and the control terminal of the second switch Q2 is connected to the second output terminal 52 of the conversion circuit. The first operational amplifier U1 constitutes a voltage follower, which can improve the stability of the second control signal during transmission.

[0034] According to some embodiments of this application, such as Figure 1 As shown, the controller 10 is used to control the second switch Q2 to turn on, and at least one second capacitor C2 is connected in parallel with the first capacitor C1. The second resistor R1, the first capacitor C1, and at least one second capacitor C2 form an RC filter circuit.

[0035] The controller 10 is used to control the second switch Q2 to turn off, and the second resistor R1 and the first capacitor C1 form an RC filter circuit.

[0036] When the breathing light requires a longer breathing cycle, the controller 10 controls one or more second switching transistors Q2 to turn on. The second capacitor C2, which is connected to the second switching transistor Q2, is connected in parallel with the first capacitor C1. The total capacitance value of the RC filter circuit increases, the rate at which the voltage amplitude of the second control signal rises or falls slows down, and the rate at which the brightness of the LED 41 changes with the voltage amplitude of the second control signal slows down, thereby making the breathing cycle of the breathing light longer.

[0037] When the breathing light requires a shorter breathing cycle, the controller 10 controls all the second switching transistors Q2 to turn off. At this time, the total capacitance of the RC filter circuit decreases, the rate at which the voltage amplitude of the second control signal rises or falls becomes faster, and the rate at which the brightness of the LED 41 changes with the voltage amplitude of the second control signal becomes faster, thereby shortening the breathing cycle of the breathing light.

[0038] In this embodiment, the controller 10 controls the second switch Q2 to be turned on, and at least one second capacitor C2 is connected in parallel with the first capacitor C1. The second resistor R1, the first capacitor C1, and at least one second capacitor C2 form an RC filter circuit. The controller 10 also controls the second switch Q2 to be turned off, and the second resistor R1 and the first capacitor C1 form the RC filter circuit. By controlling the number of times the second switch Q2 is turned on, the total capacitance value of the RC filter circuit can be changed, thus enabling flexible adjustment of the breathing light's cycle length.

[0039] According to some embodiments of this application, such as Figure 1 As shown, the filter circuit 30 in this embodiment includes a third resistor R2, a third capacitor C3, and a second operational amplifier U2. The first input terminal 32 of the second operational amplifier U2 is connected to the output terminal 24 of the first operational amplifier U1 through the third resistor R2. The first input terminal 32 of the second operational amplifier U2 is connected to the output terminal 34 of the second operational amplifier U2 through the third capacitor C3. The second input terminal 33 of the second operational amplifier U2 is grounded. The output terminal 34 of the second operational amplifier U2 is connected to the control terminal of the first switching transistor Q1.

[0040] The filter circuit 30 is used to perform secondary filtering on the second control signal. The output terminal 24 of the first operational amplifier U1 serves as the output terminal 21 of the waveform conversion circuit. The first input terminal 32 of the second operational amplifier U2 is the inverting input terminal, and the second input terminal 33 of the second operational amplifier U2 is the non-inverting input terminal. The third capacitor C3 is used to filter high-frequency noise. The first input terminal 32 of the second operational amplifier U2 is connected to the output terminal 24 of the first operational amplifier U1 through the third resistor R2 to receive the second control signal. The second input terminal 33 of the second operational amplifier U2 is grounded through the fifth resistor R4. The output terminal 34 of the second operational amplifier U2 serves as the output terminal 31 of the filter circuit and is connected to the control terminal of the first switching transistor Q1 to output the secondary filtered second control signal to the brightness control circuit 40.

[0041] Furthermore, the filter circuit 30 also includes a third switch Q3 and a fourth resistor R3. The control terminal of the third switch Q3 is connected to the third output terminal 53 of the conversion circuit, the first terminal of the third switch Q3 is connected to the first input terminal 32 of the second operational amplifier U2, and the second terminal of the third switch Q3 is connected to the output terminal 34 of the second operational amplifier U2 through the fourth resistor R3. The controller 10 controls the third switch Q3 to conduct, and the third switch Q3 is used to amplify the voltage of the second control signal.

[0042] The controller 10 controls the third switch Q3 to turn on via the third output terminal 53 of the conversion circuit. When the third switch Q3 is on, the fourth resistor R3 is used to limit the current flowing through the third switch Q3 to protect it. By setting the value of the fourth resistor R3, the voltage gain of the second operational amplifier U2 can be controlled, thereby controlling the voltage output amplitude of the second control signal.

[0043] The filter circuit 30 in this embodiment includes a third resistor R2, a fourth resistor R3, a third capacitor C3, a third switch Q3, and a second operational amplifier U2. The first input terminal 32 of the second operational amplifier U2 is connected to the output terminal 24 of the first operational amplifier U1 through the third resistor R2. The first input terminal 32 of the second operational amplifier U2 is connected to the output terminal 34 of the second operational amplifier U2 through the third capacitor C3. The second input terminal 33 of the second operational amplifier U2 is grounded. The output terminal 34 of the second operational amplifier U2 is connected to the control terminal of the first switch Q1. The control terminal of the third switch Q3 is connected to the third output terminal 53 of the conversion circuit. The first terminal of the third switch Q3 is connected to the first input terminal 32 of the second operational amplifier U2, and the second terminal of the third switch Q3 is connected to the output terminal 34 of the second operational amplifier U2 through the fourth resistor R3. The controller 10 controls the third switch Q3 to conduct, and the third switch Q3 is used to amplify the voltage of the second control signal. By setting the value of the fourth resistor R3, the voltage gain of the second operational amplifier U2 can be controlled, enabling flexible adjustment of the voltage output amplitude of the second control signal, and performing secondary filtering on the second control signal to improve the stability of signal transmission.

[0044] In some embodiments, the resistance value of the bias resistor R5 satisfies the following relationship: R5 ≥ ; Where R5 is the resistance value of the bias resistor R5. The first output terminal 51 of the conversion circuit outputs a high-level voltage. The voltage between the control terminal and the second terminal of the first switching transistor Q1. The amplification factor of the first switching transistor Q1 is... The first resistor R LED The resistance value, Reference voltage V DD voltage, For the voltage of at least one LED 41, N is the voltage between the first and second terminals of the first switching transistor Q1, and N is the number of at least one LED lamp 41.

[0045] By setting the value of the bias resistor R5, the quiescent operating point of the first switching transistor Q1 is made to fall within the amplification region of its output characteristic curve, thus ensuring that the first switching transistor Q1 always operates in the amplification state. The first resistor R... LED Used to limit the maximum current flowing through LED 41, thereby protecting LED 41. Reference voltage V DD Used to provide a stable operating power supply for LED lamp 41, and connected to the first resistor R LED Together, they limit the maximum current flowing through LED 41.

[0046] Specifically, after the filter circuit 30 performs secondary filtering and amplification of the second control signal, it outputs the second control signal to the control terminal of the first switching transistor Q1 through the bias resistor R5. By setting the resistance value of the bias resistor R5, the static operating point of the first switching transistor Q1 is always located within the amplification region of its output characteristic curve, thus enabling the first switching transistor Q1 to operate in a linear amplification state. Since the first switching transistor Q1 operates in a linear amplification state, the current flowing through the LED lamp 41 follows the voltage amplitude change of the second control signal, thereby driving the brightness change of the LED lamp 41.

[0047] In this embodiment, by setting the resistance value of the bias resistor R5, the first switching transistor Q1 is always kept in the amplification state. LED This is used to limit the maximum current flowing through LED 41, thus protecting LED 41. The second control signal also controls the current flowing through LED 41, achieving precise brightness control.

[0048] This application also provides an electronic device, including a control circuit for a breathing light according to any of the above embodiments, for controlling the brightness change of the breathing light.

[0049] In summary, the electronic device and its breathing light control circuit of this application include: a controller 10, a waveform conversion circuit 20, a filter circuit 30, and a brightness control circuit 40. The controller 10 outputs a first control signal. The waveform conversion circuit 20 is connected to the output terminal 11 of the controller and is used to convert the first control signal into a second control signal. The filter circuit 30 is connected to the output terminal 21 of the waveform conversion circuit and is used to filter the second control signal. The brightness control circuit 40 includes a first switching transistor Q1, a bias resistor R5, and at least one first resistor R. LEDAnd at least one LED 41, the control terminal of the first switching transistor Q1 is connected to the output terminal 31 of the filter circuit through the bias resistor R5, and the first terminal of the first switching transistor Q1 is connected to the corresponding first resistor R LED The LED 41 is connected to its negative terminal, and its positive terminal receives a reference voltage V. DD The second terminal of the first switching transistor Q1 is grounded, so that the first switching transistor Q1 operates in the amplification state based on the filtered second control signal. The brightness of the LED 41 follows the voltage change of the second control signal. The controller 10 does not need to have PWM function. Its output first control signal is converted and filtered to generate a smoothly changing second control signal, which drives the first switching transistor Q1 to operate in the amplification region, so that the brightness of the LED 41 follows the voltage amplitude change of the second control signal. This can support a long-period and flexibly adjustable breathing light effect and improve the control accuracy of the breathing light brightness.

[0050] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A control circuit for a breathing light, characterized in that, include: The controller is used to output the first control signal; A waveform conversion circuit, connected to the output terminal of the controller, is used to convert the first control signal into a second control signal. A filtering circuit, connected to the output of the waveform conversion circuit, is used to filter the second control signal; A brightness control circuit includes a first switching transistor, a bias resistor, at least one first resistor, and at least one LED. The control terminal of the first switching transistor is connected to the output terminal of the filter circuit through the bias resistor. The first terminal of the first switching transistor is connected to the negative terminal of the LED through the corresponding first resistor. The positive terminal of the LED receives a reference voltage. The second terminal of the first switching transistor is grounded, so that the first switching transistor operates in an amplification state based on a filtered second control signal. The brightness of the LED follows the voltage change of the second control signal.

2. The control circuit according to claim 1, characterized in that, The control circuit further includes a conversion circuit, which is connected to the output terminal of the controller. The first output terminal of the conversion circuit is connected to the waveform conversion circuit to output the first control signal to the waveform conversion circuit.

3. The control circuit according to claim 2, characterized in that, The waveform conversion circuit includes a second resistor, a first capacitor, at least one second capacitor, at least one second switching transistor, and a first operational amplifier. One end of the second resistor is connected to the first output terminal of the conversion circuit, and the other end of the second resistor is connected to the first input terminal of the first operational amplifier. The second input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier. One end of the first capacitor is connected to the first input terminal of the first operational amplifier, and the other end of the first capacitor is grounded. One end of the second capacitor is connected to the first input terminal of the first operational amplifier, and the other end of the second capacitor is connected to the first terminal of the second switching transistor. The control terminal of the second switching transistor is connected to the second output terminal of the conversion circuit.

4. The control circuit according to claim 3, characterized in that, The controller is used to control the second switch to turn on, and the at least one second capacitor is connected in parallel with the first capacitor. The second resistor, the first capacitor, and the at least one second capacitor form an RC filter circuit.

5. The control circuit according to claim 3, characterized in that, The controller is used to control the second switch to turn off, and the second resistor and the first capacitor form an RC filter circuit.

6. The control circuit according to claim 3, characterized in that, The filter circuit includes a third resistor, a third capacitor, and a second operational amplifier. The first input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier through the third resistor. The first input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier through the third capacitor. The second input terminal of the second operational amplifier is grounded. The output terminal of the second operational amplifier is connected to the control terminal of the first switching transistor.

7. The control circuit according to claim 6, characterized in that, The filtering circuit further includes a third switch and a fourth resistor. The control terminal of the third switch is connected to the third output terminal of the conversion circuit. The first terminal of the third switch is connected to the first input terminal of the second operational amplifier. The second terminal of the third switch is connected to the output terminal of the second operational amplifier through the fourth resistor.

8. The control circuit according to claim 7, characterized in that, The controller controls the third switch to turn on, and the third switch is used to amplify the voltage of the second control signal.

9. The control circuit according to claim 7, characterized in that, The resistance value of the bias resistor satisfies the following relationship: R5 ≥ ； Wherein, R5 is the resistance value of the bias resistor. The first output terminal of the conversion circuit outputs a high-level voltage. The voltage between the control terminal and the second terminal of the first switching transistor. The amplification factor of the first switching transistor is given. The resistance value of the at least one first resistor. The reference voltage, The voltage of the at least one LED lamp, The voltage between the first and second terminals of the first switching transistor is denoted as N, and N is the number of the at least one LED.

10. An electronic device, characterized in that, Includes the control circuit for the breathing light as described in any one of claims 1-9.

Images