CN217643784U - Brightness adjusting circuit and household appliance - Google Patents
Brightness adjusting circuit and household appliance Download PDFInfo
- Publication number
- CN217643784U CN217643784U CN202221345922.2U CN202221345922U CN217643784U CN 217643784 U CN217643784 U CN 217643784U CN 202221345922 U CN202221345922 U CN 202221345922U CN 217643784 U CN217643784 U CN 217643784U
- Authority
- CN
- China
- Prior art keywords
- branch
- circuit
- switching
- voltage
- resistor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The application discloses brightness control circuit and domestic appliance, brightness control circuit include luminescence unit, detect the branch road, enlarge branch road and first switch branch road. The light-emitting unit and the detection branch are both connected with the power supply, the first switch branch is connected with the light-emitting unit and the amplification branch, and the amplification branch is connected with the detection branch and the first switch branch. The detection branch circuit responds to an external detection signal to adjust the resistance value of the detection branch circuit so as to adjust the output voltage of the second end of the detection branch circuit. The amplifying branch circuit outputs a first voltage based on a difference between voltages of a first end and a second end of the amplifying branch circuit. The first switching branch circuit adjusts the conducting degree of the first switching branch circuit in response to the first voltage so as to adjust the output voltage of the second end of the first switching branch circuit and adjust the current flowing through the light emitting unit. Through the mode, the stepless regulation of the brightness of the LED lamp can be realized through hardware, a conversion interface of analog quantity and digital quantity is not needed, and the operation burden of the controller is reduced.
Description
Technical Field
The application relates to the technical field of electronic circuits, in particular to a brightness adjusting circuit and a household appliance.
Background
With the continuous improvement of the LED manufacturing technology, more and more household appliances adopt LEDs as display interfaces. Also, many household appliances need to be used at night, such as an air purifier, an air conditioner, etc., and in this case, it is necessary to reduce the brightness of the LED to prevent the sleep of a person from being affected.
Currently, the brightness of the LED is usually reduced by software control. Specifically, the ambient light brightness is collected by a photosensitive resistor and converted into a voltage signal, and the brightness of the LED is collected by a single chip microcomputer and set through software.
However, for the software control method, since the ambient light brightness needs to be collected and converted into the voltage signal, a conversion interface between the analog quantity and the digital quantity needs to be used, which may cause an increase in cost; extra codes are needed to be added, so that the operation burden of the controller is increased; meanwhile, because the output signal of the controller has a certain period, stepless regulation cannot be realized.
SUMMERY OF THE UTILITY MODEL
The application aims at providing a brightness adjusting circuit and a household appliance, and the application can realize stepless adjustment of the brightness of the LED lamp through hardware, does not need to use a conversion interface of analog quantity and digital quantity, and reduces the operation burden of a controller.
To achieve the above object, in a first aspect, the present application provides a brightness adjusting circuit, including:
the device comprises a light-emitting unit, a detection branch, an amplification branch and a first switch branch;
the first end of the light-emitting unit and the first end of the detection branch are both connected with a power supply, the second end of the light-emitting unit is connected with the third end of the first switch branch, the first end of the first switch branch is connected with the third end of the amplification branch, the first end of the amplification branch is connected with the second end of the detection branch, and the second end of the amplification branch is connected with the second end of the first switch branch;
the detection branch circuit is configured to adjust a resistance value of the detection branch circuit in response to an external detection signal so as to adjust an output voltage of the second end of the detection branch circuit, wherein the resistance value of the detection branch circuit and the output voltage of the second end of the detection branch circuit are in a negative correlation relationship;
the amplifying branch circuit is configured to output a first voltage to the first end of the first switching branch circuit based on a difference value between voltages of the first end and the second end of the amplifying branch circuit, wherein the first voltage and the difference value show a positive correlation relationship, the voltage of the first end of the amplifying branch circuit is the output voltage of the second end of the detecting branch circuit, and the voltage of the second end of the amplifying branch circuit is the output voltage of the second end of the first switching branch circuit;
the first switching branch is configured to adjust a conduction degree of the first switching branch in response to the first voltage to adjust an output voltage of the second end of the first switching branch until an absolute value of the difference is smaller than a first preset difference, and adjust a current flowing through the light emitting unit to adjust brightness of the light emitting unit, wherein the conduction degree of the first switching branch and the first voltage, the current flowing through the light emitting unit, and the output voltage of the second end of the first switching branch all exhibit positive correlation.
In an alternative form, the light emitting unit includes an LED lamp;
the anode of the LED lamp is connected with the power supply, and the cathode of the LED lamp is connected with the third end of the first switch branch.
In an alternative mode, the detection branch comprises a photoresistor and a first resistor;
the first end of the photoresistor is connected with the power supply, and the second end of the photoresistor is respectively connected with the first end of the first resistor and the first end of the amplifying branch circuit.
In an alternative mode, the amplifying branch comprises an amplifier;
the non-inverting input end of the amplifier is connected with the second end of the detection branch, the inverting input end of the amplifier is connected with the second end of the first switch branch, and the output end of the amplifier is connected with the first end of the first switch branch.
In an optional mode, the first switching branch comprises a first switching tube, a second resistor and a third resistor;
the first end of the first switch tube is connected with the third end of the amplifying branch circuit and the first end of the third resistor respectively, the second end of the first switch tube is connected with the first end of the second resistor and the second end of the amplifying branch circuit respectively, the third end of the first switch tube is connected with the second end of the light-emitting unit, and the second end of the second resistor and the second end of the third resistor are both grounded.
In an optional manner, the brightness adjusting circuit further includes a second switching branch and a controller, wherein the second switching branch is connected between the first switching branch and the amplifying branch;
the first end of the second switching branch is connected with the controller, the second end of the second switching branch is connected with the first end of the first switching branch, and the third end of the second switching branch is connected with the third end of the amplifying branch;
the second switching branch is configured to turn on or off a connection between the first terminal of the first switching branch and the third terminal of the amplifying branch in response to a control signal output by the controller.
In an optional mode, the second switching branch comprises a second switching tube and a fourth resistor;
the first end of the second switch tube is connected with the first end of the fourth resistor and the controller respectively, the second end of the second switch tube is connected with the first end of the first switch branch, the third end of the second switch tube is connected with the third end of the amplifying branch, and the second end of the fourth resistor is grounded.
In a second aspect, the present application provides a household appliance comprising the brightness adjustment circuit as described above.
The beneficial effect of this application is: the application provides a brightness control circuit includes luminescence unit, detection branch road, enlargies branch road and first switch branch road. The light-emitting unit and the detection branch are connected with the power supply, the first switch branch is connected with the light-emitting unit and the amplification branch, and the amplification branch is connected with the detection branch and the first switch branch. When the detection signal changes, the detection branch circuit adjusts the resistance value thereof so as to adjust the output voltage of the second end of the detection branch circuit. At this time, a difference between the voltages of the first end and the second end of the amplifying branch circuit is also changed, so that the first voltage is also changed, the conduction degree of the first switching branch circuit is adjusted, and the output voltage of the second end of the first switching branch circuit and the current flowing through the light emitting unit are adjusted. Until the absolute value of the difference between the voltages of the first end and the second end of the amplifying branch circuit is smaller than a first preset difference, the whole circuit keeps dynamic balance, the current also keeps stable, and then the brightness of the light-emitting unit keeps stable. And, the current flowing through the light emitting unit is different under different detection signals. Then, if the detection signal is the ambient light brightness, and the ambient light brightness is stronger, the smaller the resistance value of the detection branch is, the smaller the output voltage of the second end of the detection branch is. When the temperature is at night, the ambient light brightness is weakened, the resistance value of the detection branch is increased, and since the resistance value of the detection branch and the output voltage of the second end of the detection branch are in a negative correlation relationship, the output voltage of the second end of the detection branch is reduced, so that the difference between the voltages of the first end and the second end of the amplification branch is reduced. And since the first voltage and the difference value present a positive correlation, the first voltage is also reduced. Then, since the conduction degree of the first switch branch circuit and the first voltage, the current flowing through the light-emitting unit, and the output voltage of the second end of the first switch branch circuit are all in positive correlation, the conduction degree of the first switch branch circuit, the output voltage of the second end of the first switch branch circuit, and the current flowing through the light-emitting unit are all reduced, the brightness of the light-emitting unit is gradually reduced until the absolute value of the difference between the voltages of the first end and the second end of the amplifying branch circuit is smaller than a first preset difference, and the current flowing through the light-emitting unit is kept stable and is smaller than the current before the environmental brightness becomes weak. Conversely, if the ambient light brightness increases, the brightness of the light-emitting unit also increases. Therefore, through the mode, the brightness of the light-emitting unit can be changed in real time along with the size of the detection signal through the hardware structure, namely, the stepless adjustment of the light-emitting unit can be realized through the hardware, and when the light-emitting unit is an LED lamp, the stepless adjustment of the LED lamp can be realized through the hardware. Meanwhile, because conversion between the analog quantity and the digital quantity is not required to be realized, a conversion interface of the analog quantity and the digital quantity is not required to be used as in the related art, and code control is not required, so that the operation burden of the controller is reduced.
Drawings
One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.
Fig. 1 is a schematic structural diagram of a brightness adjusting circuit according to an embodiment of the present disclosure;
fig. 2 is a schematic circuit structure diagram of a brightness adjusting circuit according to an embodiment of the present disclosure.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a brightness adjusting circuit according to an embodiment of the present disclosure. As shown in fig. 1, the brightness adjusting circuit 100 includes a light emitting unit 10, a detecting branch 20, an amplifying branch 30 and a first switching branch 40.
The first end of the light emitting unit 10 and the first end of the detection branch 20 are both connected to the power VCC, the second end of the light emitting unit 10 is connected to the third end of the first switch branch 40, the first end of the first switch branch 40 is connected to the third end of the amplification branch 30, the first end of the amplification branch 30 is connected to the second end of the detection branch 20, and the second end of the amplification branch 30 is connected to the second end of the first switch branch 40.
Specifically, the detecting branch 20 is configured to adjust a resistance value of the detecting branch 20 in response to an external detecting signal to adjust the output voltage of the second end of the detecting branch 20, wherein the resistance value of the detecting branch 20 and the output voltage of the second end of the detecting branch 20 have a negative correlation. The amplifying branch 30 is configured to output a first voltage to the first end of the first switching branch 40 based on a difference between voltages of the first end and the second end of the amplifying branch 30, wherein the first voltage and the difference have a positive correlation, the voltage of the first end of the amplifying branch 30 is an output voltage of the second end of the detecting branch 20, and the voltage of the second end of the amplifying branch 30 is an output voltage of the second end of the first switching branch 40. The first switching branch 40 is configured to adjust a conduction degree of the first switching branch 40 in response to the first voltage to adjust an output voltage of the second end of the first switching branch 40 until an absolute value of the difference is smaller than a first preset difference, and adjust a current flowing through the light emitting unit 10 to adjust the brightness of the light emitting unit 10, wherein the conduction degree of the first switching branch 40 and the first voltage, the current flowing through the light emitting unit 10 and the output voltage of the second end of the first switching branch 40 all exhibit a positive correlation.
In practical applications, an external detection signal is taken as the ambient light brightness, and the ambient light brightness and the resistance value of the detection branch 20 show a negative correlation, that is, the resistance value of the detection branch 20 decreases with the increase of the ambient light brightness, and the resistance value of the detection branch 20 increases with the decrease of the ambient light brightness.
Then, when the ambient light brightness gradually decreases from morning to night, the resistance value of the detection branch 20 gradually increases. Since the resistance value of the detecting branch 20 and the output voltage of the second end of the detecting branch 20 have a negative correlation, that is, the output voltage of the second end of the detecting branch 20 decreases with the increase of the resistance value thereof, and the output voltage of the second end of the detecting branch 20 increases with the decrease of the resistance value thereof, the output voltage of the second end of the detecting branch 20 decreases. At this time, the voltage of the first terminal of the amplifying branch 30 decreases, and the voltage of the second terminal of the amplifying branch 30 does not change, so that the difference between the first terminal and the second terminal of the amplifying branch 30 decreases. Since the first voltage output by the amplifying branch 30 has a positive correlation with the difference, that is, the first voltage increases with the increase of the difference, and the first voltage decreases with the decrease of the difference, the first voltage output by the amplifying branch 30 decreases, and the conducting degree of the first switching branch 40 also decreases with the decrease of the difference. Since the conduction degree of the first switching branch 40 and the current flowing through the light emitting unit have a positive correlation, that is, the current flowing through the light emitting unit 10 gradually decreases, that is, the brightness of the light emitting unit 10 gradually decreases. Meanwhile, the conduction degree of the first switch branch 40 and the output voltage of the second end of the first switch branch 40 also present a positive correlation relationship, that is, the output voltage of the second end of the first switch branch 40 gradually decreases. As can be seen from the foregoing, the output voltage at the second end of the detection branch 20 decreases, that is, the voltage at the first end of the amplification branch 30 decreases, and as the output voltage at the second end of the first switching branch 40 also decreases, the output voltage at the second end of the first switching branch 40 gradually approaches to the output voltage at the second end of the detection branch 20 until the absolute value of the difference between the output voltage at the second end of the detection branch 20 and the output voltage at the second end of the first switching branch 40 is smaller than a first preset difference, that is, the difference between the voltages at the first end and the second end of the amplification branch 30 is smaller than the first preset difference, and the output voltage at the second end of the detection branch 20 and the output voltage at the second end of the first switching branch 40 are both kept unchanged. At this time, the current flowing through the light emitting unit 10 also remains unchanged, i.e., the luminance of the light emitting unit 10 remains unchanged.
The first preset difference value may be set according to an actual application situation, which is not specifically limited in the embodiment of the present application.
In summary, when the ambient light brightness is gradually reduced, it can be achieved that the circuit flowing through the light emitting unit 10 is gradually reduced even if the brightness of the light emitting unit 10 is also gradually reduced. Of course, it is also possible to realize a gradual increase in the circuit flowing through the light emitting unit 10 when the ambient light brightness gradually decreases, even if the brightness of the light emitting unit 10 also gradually increases. Moreover, the brightness of the light-emitting unit 10 can be adjusted in real time along with the change of the ambient light brightness, i.e. the brightness adjustment of the light-emitting unit 10 is a stepless adjustment mode. Therefore, in this embodiment, the stepless adjustment of the light emitting unit 10 is realized by a hardware structure, and when the light emitting unit 10 is an LED lamp, the stepless adjustment of the LED lamp is realized by the hardware structure. Compared with the prior art, the mode that software control can only achieve adjustment of a plurality of gears is adopted, different requirements of users can be better met, and the practicability is high.
Meanwhile, since conversion between analog quantity and digital quantity is not required to be realized, it is not necessary to use a conversion interface of analog quantity and digital quantity as in the related art, and it is possible to prevent an increase in cost due to an increase in conversion interface of analog quantity and digital quantity. And moreover, code control is not needed, so that the operation load of the controller is reduced.
One structure of the light emitting unit 10 is exemplarily shown in fig. 2. As shown in fig. 2, the light emitting unit 10 includes an LED lamp LE1. The anode of the LED lamp LE1 is connected to the power source VCC, and the cathode of the LED lamp LE1 is connected to the third end of the first switching branch 40.
The brightness of the LED lamp LE1 and the current flowing through the LED lamp LE1 are in a positive correlation relationship, namely the larger the current flowing through the LED lamp LE1 is, the stronger the brightness of the LED lamp LE1 is; the smaller the current flowing through the LED lamp LE1, the lower the brightness of the LED lamp LE1. The anode of the LED lamp LE1 is a first end of the light emitting unit 10, and the cathode of the LED lamp LE1 is a second end of the light emitting unit 10.
It is understood that in this embodiment, the light emitting unit 10 is taken as an LED lamp, and in other embodiments, the light emitting unit 10 may also be a microled or an organic light emitting element, such as an organic light emitting diode (oeld). Of course, the light emitting unit 10 may also be an inorganic light emitting element, which is not limited herein.
One configuration of the detection branch 20 is also illustrated in fig. 2. As shown in fig. 2, the detecting branch 20 includes a photo resistor RL and a first resistor R1. A first end of the photo resistor RL is connected to the power source VCC, and a second end of the photo resistor RL is connected to a first end of the first resistor R1 and a first end of the amplifying branch 30, respectively. The first end of the photo resistor RL is a first end of the detection branch 20, and the second end of the photo resistor RL is a second end of the detection branch 20.
The common manufacturing material of the photoresistor RL is cadmium sulfide, and in addition, selenium, aluminum sulfide, lead sulfide, bismuth sulfide and other materials are also used. These materials have the property of rapidly decreasing their resistance under illumination with light of a specific wavelength. The reason is that the carriers generated by illumination all participate in conduction, and do drift motion under the action of an external electric field, electrons rush to the anode of the power supply, and holes rush to the cathode of the power supply, so that the resistance value of the photoresistor RL is rapidly reduced. In other embodiments, the light sensor RL may be replaced by other components capable of changing the resistance value based on the intensity of the ambient light, such as a light pipe (photo conductor).
In this embodiment, the photo resistor RL and the first resistor R1 form a voltage dividing circuit to divide the voltage of the power source VCC. The voltage at the connection point between the photo resistor RL and the first resistor R1 is the divided voltage of the power source VCC across the first resistor R1, and the voltage is also the voltage at the first end of the amplifying branch 30.
Specifically, when the external detection signal is the ambient light brightness, if the ambient light brightness is gradually increased, the resistance value of the photo resistor RL is gradually decreased; if the ambient light brightness gradually decreases, the resistance of the photo resistor RL gradually increases. That is, the intensity of the ambient light intensity and the resistance value of the photo resistor RL show a negative correlation.
One configuration of the amplifying leg 30 is also illustrated in fig. 2. As shown in fig. 2, the amplification branch 30 includes an amplifier U2.
The non-inverting input terminal of the amplifier U2 is connected to the second terminal of the detection branch 20, the inverting input terminal of the amplifier U2 is connected to the second terminal of the first switching branch 40, and the output terminal of the amplifier U2 is connected to the first terminal of the first switching branch 40. The non-inverting input terminal of the amplifier U2 is the first terminal of the amplifying branch 30, the inverting input terminal of the amplifier U2 is the second terminal of the amplifying branch 30, and the output terminal of the amplifier U2 is the third terminal of the amplifying branch 30.
In this embodiment, the voltage at the non-inverting input of the amplifier U2 is denoted as U + Let the voltage at the inverting input of amplifier U2 be U - Then, the voltage Uo at the output terminal of the amplifier U2 (which corresponds to the first voltage in the above embodiment) is: uo = Au [ (. U ]) ] + -U - ) And Au is the amplification factor of the amplifier U2. U shape + -U - The difference between the non-inverting input terminal and the inverting input terminal of the amplifier U2 (the voltage corresponds to the difference between the voltages of the first terminal and the second terminal of the amplifying branch 30 in the above embodiment), the voltage Uo has a positive correlation with the difference, that is, the first voltage has a positive correlation with the difference. The amplifier U2 may be an operational amplifier.
One configuration of the first switching leg 40 is also illustrated in fig. 2. As shown in fig. 2, the first switching branch 40 includes a first switching tube Q1, a second resistor R2 and a third resistor R3.
The first end of the first switch tube Q1 is connected to the third end of the amplifying branch 30 and the first end of the third resistor R3, the second end of the first switch tube Q1 is connected to the first end of the second resistor R2 and the second end of the amplifying branch 30, the third end of the first switch tube Q1 is connected to the second end of the light emitting unit 10, and the second end of the second resistor R2 and the second end of the third resistor R3 are both grounded to GND. The first end of the first switch tube Q1 is the first end of the first switch branch 40, the second end of the first switch tube Q1 is the second end of the first switch branch 40, and the third end of the first switch tube Q1 is the third end of the first switch branch 40.
In this embodiment, the first switch tube Q1 operates in the amplification region, at this time, the current of the second end of the first switch tube Q1 is controlled by the current of the first end of the first switch tube Q1, and the current of the second end of the first switch tube Q1 and the current of the first end of the first switch tube Q1 show a positive correlation, that is, the current of the second end of the first switch tube Q1 increases with the increase of the current of the first end of the first switch tube Q1, and decreases with the decrease of the current of the first end of the first switch tube Q1. And the current of the first end of the first switch tube Q1 and the voltage of the first end of the first switch tube Q1 have a positive correlation, that is, the current of the first end of the first switch tube Q1 increases with the increase of the voltage of the first end of the first switch tube Q1, and decreases with the decrease of the voltage. In summary, the voltage at the first end of the first switch Q1 and the current at the third end of the first switch Q1 are in a positive correlation, that is, the first voltage output by the amplifier U2 and the current at the third end of the first switch Q1 are in a positive correlation.
Therefore, when the first voltage output by the amplifier U2 increases, the current at the third end of the first switching tube Q1 increases, and the current at the third end of the first switching tube Q1 is also the current flowing through the LED lamp LE1 and the second resistor R2, that is, the current flowing through the LED lamp LE1 and the second resistor R2 also increases, so that the brightness of the LED lamp LE1 increases. At the same time, the voltage across the second resistor R2 increases, i.e., the voltage input to the inverting input of the amplifier U2 increases.
Conversely, when the first voltage output by the amplifier U2 decreases, the current at the third end of the first switching tube Q1 decreases, the current flowing through the LED lamp LE1 and the second resistor R2 also decreases, and the brightness of the LED lamp LE1 decreases. At the same time, the voltage across the second resistor R2 decreases, i.e., the voltage input to the inverting input of the amplifier U2 decreases.
In this embodiment, the first switch Q1 is an NPN transistor as an example. The base electrode of the NPN type triode is the first end of the first switch tube Q1, the emitter electrode of the NPN type triode is the second end of the first switch tube Q1, and the collector electrode of the NPN type triode is the third end of the first switch tube Q1.
In addition, the first switch Q1 may be any controllable switch, such as an Insulated Gate Bipolar Transistor (IGBT) device, an Integrated Gate Commutated Thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a Silicon Controlled Rectifier (SCR) device, a junction gate field effect transistor (JFET) device, a MOS Controlled Thyristor (MCT) device, and the like. In addition, the first switching tube Q1 shown in fig. 2 may be implemented as a plurality of switches connected in parallel.
In an embodiment, as shown in fig. 2, the brightness adjusting circuit 100 further includes a second switching branch 50 and a controller U1. Wherein the second switching branch 50 is connected between the first switching branch 40 and the amplifying branch 30.
A first end of the second switching branch 50 is connected to the controller U1, a second end of the second switching branch 50 is connected to a first end of the first switching branch 40, and a third end of the second switching branch 50 is connected to a third end of the amplifying branch 30.
Specifically, the second switching branch 50 is configured to turn on or off the connection between the first terminal of the first switching branch 40 and the third terminal of the amplifying branch 30 in response to a control signal output from the controller U1.
In this embodiment, by providing the second switching branch 50 between the first switching branch 40 and the amplifying branch 30, the on and off of the first switching branch 40 can be controlled by controlling the on and off of the second switching branch 50, and the on and off of the LED lamp LE1 can be further controlled. Specifically, when the second switching branch 50 is turned on, the first switching branch 40 is connected to the amplifying branch 30, the LED lamp LE1 is turned on due to power supply, and at this time, as described in the above embodiment, the LED lamp LE1 adjusts the real-time brightness thereof according to the magnitude of the detection signal; when the second switching branch 50 is disconnected, the connection between the first switching branch 40 and the amplifying branch 30 is disconnected, the first switching branch 40 is disconnected, and the LED lamp LE1 is turned off due to power loss.
Therefore, by providing the second switching branch 50, the lighting or extinguishing of the LED lamp LE1 can be further controlled.
For example, in one embodiment, the brightness adjusting circuit 100 is provided in an air conditioner, and the LED lamp LE1 serves as a display interface of the air conditioner. The controller U1 may be a remote controller for controlling the air conditioner, and the LED lamp LE1 may be turned off by outputting a control signal through the remote controller to control the second switching branch 50 to be turned off; the LED lamp LE1 can be turned on by outputting a control signal through the remote controller to control the second switching branch 50 to be turned on. When the LED lamp LE1 is turned on, the brightness of the LED lamp LE1 can be automatically adjusted in real time according to the brightness of the ambient light.
Fig. 2 also illustrates a configuration of the second switching branch 50. As shown in fig. 2, the second switching branch 50 includes a second switching tube Q2 and a fourth resistor R4.
The first end of the second switch tube Q2 is connected to the first end of the fourth resistor R4 and the controller U1, the second end of the second switch tube Q2 is connected to the first end of the first switch branch 40, the third end of the second switch tube Q2 is connected to the third end of the amplifying branch 30, and the second end of the fourth resistor R4 is grounded GND. The first end of the second switching tube Q2 is a first end of the second switching branch 50, the second end of the second switching tube Q2 is a second end of the second switching branch 50, and the third end of the second switching tube Q2 is a third end of the second switching branch 50.
Specifically, when the voltage of the control signal output by the controller U1 is greater than the conduction voltage drop of the second switching tube Q2, the second switching tube Q2 is turned on; conversely, when the voltage of the control signal output by the controller U1 is smaller than the conduction voltage drop of the second switch tube Q2, the second switch tube Q2 is turned off. Secondly, since the second switch tube Q2 has a built-in diode therein, when the second switch tube Q2 is turned off, the capacitance stored in the built-in diode can be consumed by providing the fourth resistor R4, so that the second switch tube Q2 can be turned off quickly.
The principle of the circuit configuration shown in fig. 2 is explained below. Meanwhile, an external detection signal is taken as the ambient light brightness as an example.
When the controller U1 outputs a control signal to control the second switching tube Q2 to be disconnected, the connection between the first switching tube Q1 and the amplifier U2 is disconnected, the voltage of the first end of the first switching tube Q1 is grounded GND after passing through the third resistor R3, and is forcibly pulled low, so that the first switching tube Q1 is disconnected. The loop where the LED lamp LE1 is located is disconnected, and the LED lamp LE1 is turned off due to power loss.
When the controller U1 outputs a control signal to control the second switching tube Q2 to be conducted, the first switching tube Q1 is communicated with the amplifier U2. The conduction degree of the first switch tube Q1 and the first voltage output by the amplifier U1 show a positive correlation.
Specifically, when the ambient light brightness is increased, the resistance value of the photo resistor RL is decreased, the divided voltage of the first resistor R1 is increased, the voltage of the non-inverting input terminal of the comparator U2 is increased, the first voltage output by the comparator U2 is increased, and the conduction degree of the first switch tube Q1 is increased. The current of the loop in which the LED lamp LE1, the first switching tube Q1 and the second resistor R2 are located gradually increases, the brightness of the LED lamp LE1 gradually increases, and the voltage across the second resistor R2 gradually increases, that is, the voltage at the inverting input terminal of the comparator U2 gradually increases and tends to the voltage at the non-inverting input terminal of the comparator U2. Until the absolute value of the difference between the voltage of the non-inverting input terminal of the comparator U2 and the voltage of the inverting input terminal of the comparator U2 is smaller than the first preset difference, the first voltage output by the comparator U2 remains unchanged, the current flowing through the LED lamp LE1 also remains unchanged, and the brightness of the LED lamp LE1 remains unchanged. However, it is understood that after the brightness of the LED lamp LE1 is maintained, the brightness of the LED lamp LE1 is stronger than the brightness of the LED lamp LE1 when the brightness of the ambient light is not enhanced. Thus, when the ambient light brightness increases, the brightness of the LED lamp LE1 also increases.
When the intensity of the ambient light decreases, the brightness of the LED lamp LE1 can be determined to decrease accordingly by using the similar analysis as described above.
Meanwhile, when the absolute value of the difference between the voltage of the non-inverting input terminal of the comparator U2 and the voltage of the inverting input terminal of the comparator U2 is smaller than the first preset difference, the voltage of the non-inverting input terminal of the comparator U2 and the voltage of the inverting input terminal of the comparator U2 may be approximately considered to be equal. The voltage at the non-inverting input of the amplifier U2 is still denoted as U + Let us denote the voltage at the inverting input of the amplifier U2 as U - Then U at this time + ≈U - (1). Wherein, U + ＝VCC*r1/(r1+rL)(2)，U - And = ILE1 × R2 (3), where R1 is a resistance value of the first resistor R1, rL is a resistance value of the photo resistor rL, ILE1 is a current flowing through the LED lamp LE1, and R2 is a resistance value of the second resistor R2. By combining equations (1), (2) and (3), we can obtain: ILE1 ≈ VCC r1/[ (r 1+ rL) r 2)](4). As can be seen from equation (4), when the resistance of the first resistor R1, the resistance of the second resistor R2 and the power VCC are all kept unchanged, the current flowing through the LED lamp LE1 and the resistance of the photo resistor RL are in a negative correlation relationship, and when the resistance of the photo resistor RL is increased, the current flowing through the LED lamp LE1 is decreased, and the brightness of the LED lamp LE1 is reduced; when the resistance value of the photo resistor RL is decreased, the current flowing through the LED lamp LE1 is increased, and the brightness of the LED lamp LE1 is increased.
Then, by combining the negative correlation relationship between the resistance value of the photosensitive resistor RL and the ambient light intensity, the resistance value of the photosensitive resistor RL is reduced, the current flowing through the LED lamp LE1 is increased, and the brightness of the LED lamp LE1 is enhanced when the ambient light intensity is enhanced; when the intensity of the ambient light is reduced, the resistance value of the photosensitive resistor RL is increased, the current flowing through the LED lamp LE1 is reduced, and the brightness of the LED lamp LE1 is reduced.
The embodiment of the present application further provides a household appliance, which includes the brightness adjusting circuit 100 in any embodiment of the present application.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; within the context of the present application, where technical features in the above embodiments or in different embodiments may also be combined, the steps may be implemented in any order and there are many other variations of the different aspects of the present application described above which are not provided in detail for the sake of brevity; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.
Claims (8)
1. A brightness adjustment circuit, comprising:
the device comprises a light-emitting unit, a detection branch, an amplification branch and a first switch branch;
the first end of the light-emitting unit and the first end of the detection branch circuit are both connected with a power supply, the second end of the light-emitting unit is connected with the third end of the first switch branch circuit, the first end of the first switch branch circuit is connected with the third end of the amplification branch circuit, the first end of the amplification branch circuit is connected with the second end of the detection branch circuit, and the second end of the amplification branch circuit is connected with the second end of the first switch branch circuit;
the detection branch circuit is configured to adjust a resistance value of the detection branch circuit in response to an external detection signal so as to adjust an output voltage of the second end of the detection branch circuit, wherein the resistance value of the detection branch circuit and the output voltage of the second end of the detection branch circuit are in a negative correlation relationship;
the amplifying branch circuit is configured to output a first voltage to the first end of the first switching branch circuit based on a difference value between voltages of the first end and the second end of the amplifying branch circuit, wherein the first voltage and the difference value show a positive correlation relationship, the voltage of the first end of the amplifying branch circuit is the output voltage of the second end of the detecting branch circuit, and the voltage of the second end of the amplifying branch circuit is the output voltage of the second end of the first switching branch circuit;
the first switching branch is configured to adjust a conduction degree of the first switching branch in response to the first voltage to adjust an output voltage of the second end of the first switching branch until an absolute value of the difference is smaller than a first preset difference, and adjust a current flowing through the light emitting unit to adjust brightness of the light emitting unit, wherein the conduction degree of the first switching branch and the first voltage, the current flowing through the light emitting unit, and the output voltage of the second end of the first switching branch all exhibit positive correlation.
2. The brightness adjusting circuit according to claim 1, wherein the light emitting unit includes an LED lamp;
the anode of the LED lamp is connected with the power supply, and the cathode of the LED lamp is connected with the third end of the first switch branch.
3. The circuit of claim 1, wherein the detection branch comprises a photo resistor and a first resistor;
the first end of the photoresistor is connected with the power supply, and the second end of the photoresistor is respectively connected with the first end of the first resistor and the first end of the amplifying branch circuit.
4. The brightness adjusting circuit of claim 1, wherein the amplifying branch comprises an amplifier;
the non-inverting input end of the amplifier is connected with the second end of the detection branch, the inverting input end of the amplifier is connected with the second end of the first switch branch, and the output end of the amplifier is connected with the first end of the first switch branch.
5. The circuit of claim 1, wherein the first switch branch comprises a first switch tube, a second resistor and a third resistor;
the first end of the first switch tube is connected with the third end of the amplifying branch circuit and the first end of the third resistor respectively, the second end of the first switch tube is connected with the first end of the second resistor and the second end of the amplifying branch circuit respectively, the third end of the first switch tube is connected with the second end of the light-emitting unit, and the second end of the second resistor and the second end of the third resistor are both grounded.
6. The brightness adjusting circuit of claim 1, further comprising a second switching branch and a controller, wherein the second switching branch is connected between the first switching branch and the amplifying branch;
the first end of the second switching branch is connected with the controller, the second end of the second switching branch is connected with the first end of the first switching branch, and the third end of the second switching branch is connected with the third end of the amplifying branch;
the second switching branch is configured to turn on or off a connection between the first terminal of the first switching branch and the third terminal of the amplifying branch in response to a control signal output from the controller.
7. The brightness control circuit according to claim 6, wherein the second switching branch comprises a second switching tube and a fourth resistor;
the first end of the second switch tube is connected with the first end of the fourth resistor and the controller respectively, the second end of the second switch tube is connected with the first end of the first switch branch, the third end of the second switch tube is connected with the third end of the amplifying branch, and the second end of the fourth resistor is grounded.
8. A household appliance comprising a brightness adjustment circuit according to any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221345922.2U CN217643784U (en) | 2022-05-31 | 2022-05-31 | Brightness adjusting circuit and household appliance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221345922.2U CN217643784U (en) | 2022-05-31 | 2022-05-31 | Brightness adjusting circuit and household appliance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN217643784U true CN217643784U (en) | 2022-10-21 |
Family
ID=83621820
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221345922.2U Active CN217643784U (en) | 2022-05-31 | 2022-05-31 | Brightness adjusting circuit and household appliance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN217643784U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116685014A (en) * | 2023-08-04 | 2023-09-01 | 无锡安特源科技股份有限公司 | Dimming control circuit and electronic equipment |
-
2022
- 2022-05-31 CN CN202221345922.2U patent/CN217643784U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116685014A (en) * | 2023-08-04 | 2023-09-01 | 无锡安特源科技股份有限公司 | Dimming control circuit and electronic equipment |
| CN116685014B (en) * | 2023-08-04 | 2023-10-20 | 无锡安特源科技股份有限公司 | Dimming control circuit and electronic equipment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103858521B (en) | LED illumination device | |
| CA2024440C (en) | Dimmer control circuit | |
| CN101572984B (en) | Image ratio constant flow source circuit driving multipath light emitting diode | |
| US8310163B2 (en) | Microcontroller-based lighting control system and method for lighting control | |
| TWI425862B (en) | Two-terminal current controller and related led lighting device | |
| CN217643784U (en) | Brightness adjusting circuit and household appliance | |
| CN212278507U (en) | Deep dimming circuit | |
| US10517151B1 (en) | Linear constant-current LED light circuit | |
| CN114423110B (en) | Circuit structure for hysteresis control | |
| TW201143515A (en) | Illuminating apparatus and light source control circuit thereof | |
| US20040017158A1 (en) | Smart dimmer switch for maintaining constant luminance in a lighting environment | |
| WO2018157345A1 (en) | Led lamp and led brightness regulation circuit | |
| WO2017139251A1 (en) | Light source driving circuits for triac dimmer | |
| CN216531870U (en) | Light sensing switch circuit and light sensing system | |
| CN212231780U (en) | LED drive circuit and LED lighting device | |
| CN211184327U (en) | Load driving circuit with power switch adjusting function and lighting driving system thereof | |
| TWI552645B (en) | Dimming circuit | |
| CN107613603A (en) | LED delays bright control system | |
| CN210899752U (en) | Intelligent lighting control system | |
| CN104202868A (en) | Control circuit for controlling on and off of working electric appliance based on outside light and working electric appliance | |
| CN206517633U (en) | Can be by dimming the LED drive power turned off | |
| CN205029943U (en) | LED driver based on damping circuit | |
| CN205051938U (en) | Active offset voltage type LED drive circuit who adjusts of phase place | |
| CN107277971B (en) | Light-operated switch circuit of LED lamp | |
| CN217011244U (en) | Color-changing lamp with memory |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |