Small night lamp control circuit capable of automatically controlling dimming without single chip microcomputer

Abstract

The utility model relates to a small night lamp control circuit capable of automatically controlling dimming without a single chip microcomputer, which comprises a rectifying and filtering circuit, a power conversion circuit connected with the rectifying and filtering circuit, an LED driving circuit connected with the power conversion circuit, and an auxiliary power supply circuit, the dimming signal circuit and the illumination detection circuit are connected with the auxiliary power supply circuit, the illumination detection circuit is connected with the dimming signal circuit and the LED drive circuit, the dimming signal circuit is connected with the LED drive circuit, and the LED drive circuit is connected with a lamp. According to the utility model, function conversion can be realized without a single-chip microcomputer, and the illumination intensity in the current state can be detected in real time to carry out more linear and reasonable dimming. And along with the change of illumination, the lamp is started to work at dusk and has the maximum brightness, and along with the falling of night, the lamp reaches the minimum dimming value at late night, so that the lamp is more in line with the feeling of a human body.

Description

Technical Field

[0001] This utility model relates to the field of lighting control circuit technology, and in particular to a control circuit for a night light with automatic dimming control without a microcontroller. Background Technology

[0002] In the design of LED night lights, manual control or microcontroller programming is required. However, the clock signal is greatly affected by the season, and the experience at the same time in summer and winter is different. Summary of the Invention

[0003] The purpose of this utility model is to provide a microcontroller-free automatic dimming control circuit for night lights, which can solve or at least alleviate one or more of the above-mentioned problems and other problems existing in the prior art.

[0004] To achieve the above objectives, this utility model provides a microcontroller-free automatic dimming control circuit for a night light, wherein the microcontroller-free automatic dimming control circuit includes:

[0005] The system includes a rectifier and filter circuit, a power conversion circuit connected to the rectifier and filter circuit, an LED driver circuit and an auxiliary power supply circuit connected to the power conversion circuit, a dimming signal circuit and a light detection circuit connected to the auxiliary power supply circuit, the light detection circuit being connected to the dimming signal circuit and the LED driver circuit, the dimming signal circuit being connected to the LED driver circuit, and the LED driver circuit being connected to the lamp.

[0006] In the aforementioned microcontroller-free automatic dimming control circuit for a night light, the light detection circuit includes chip U4. Pin 1 of chip U4 is connected to one end of resistor R11, the other end of resistor R11 is connected to a 3-0V power supply, one end of resistor R112 is connected, and the other end of resistor R112 is grounded. Pin 2 of chip U4 is connected to one end of resistor R109 and one end of resistor R110, the other end of resistor R109 is connected to pin 1 of chip U4 and a 6-0V power supply. Pin 3 of chip U4 is connected to one end of resistor R106 and one end of resistor R108, the other end of resistor R106 is grounded, and the other end of resistor R108 is connected to a 6V power supply. Pin 4 of chip U4 is grounded. Pin 5 of chip U4 is connected to resistor R104. One end of the resistor R103 is connected to the ground. The other end of the resistor R104 is grounded. The other end of the resistor R103 is connected to the positive terminal of the diode D100, the emitter of the transistor, one end of the resistor R101, one end of the resistor R102, one end of the capacitor C110, and a 3-0V power supply. The other ends of the resistor R101, the other ends of the resistor R102, and the other ends of the capacitor C110 are all grounded. The collector of the transistor is connected to the negative terminal of the LED2 and a +12V power supply. The base of the transistor is connected to the positive terminal of the LED2. The negative terminal of the diode D100 is connected to the dimming signal circuit. Pin 6 of the chip U4 is connected to the other end of the resistor R110 and pin 7 of the chip U4. Pin 8 of the chip U4 is connected to a 12V power supply.

[0007] In the aforementioned microcontroller-free automatic dimming control circuit for nightlights, the rectifier and filter circuit includes an electrolytic capacitor EC1. One end of the electrolytic capacitor EC1 is connected to the positive input terminal of the power supply, one end of the electrolytic capacitor EC7, one end of the electrolytic capacitor C101, one end of the resistor R6, and the power conversion circuit. The other ends of the electrolytic capacitor EC1, EC7, C101, and R6 are all grounded.

[0008] In the aforementioned microcontroller-free automatic dimming control circuit for a night light, the dimming signal circuit includes chip U5. Pin 1 of chip U5 is connected to one end of resistor R99, and the other end of resistor R99 is connected to the LED driver circuit. Pin 2 of chip U5 is connected to one end of resistor R93, one end of capacitor C90, and a 1.75-3V power supply, with the other end of capacitor C90 grounded. Pin 3 of chip U5 is connected to one end of resistor R96, one end of resistor R97, one end of resistor R98, and a 2-9.2V power supply, with the other end of resistor R96 connected to a 6V power supply. The other end is grounded, and the other end of resistor R98 is connected to the negative terminal of diode D100; pin 4 of chip U5 is grounded; pin 5 of chip U5 is connected to one end of resistor R95, one end of resistor R91, and one end of resistor R92, the other end of resistor R92 is grounded, and the other end of resistor R91 is connected to a +12V power supply; pin 6 of chip U5 is connected to one end of resistor R93, the other end of resistor R93 is connected to one end of resistor R94, the other end of resistor R95, and pin 7 of chip U5, the other end of resistor R94 is connected to a +12V power supply; pin 8 of chip U5 is connected to a +12V power supply.

[0009] In the aforementioned microcontroller-free automatic dimming control circuit for a night light, the LED driver circuit includes a chip U3. Pin 1 of chip U3 is connected to one end of capacitor C10, and the other end of capacitor C10 is grounded. Pin 2 of chip U3 is connected to one end of capacitor C9, one end of resistor R56, and the other end of resistor R99. The other ends of capacitor C9 and capacitor R56 are grounded. Pin 3 of chip U3 is connected to one end of capacitor C6, one end of resistor R18, and one end of resistor R13. The other ends of capacitor C6 and resistor R18 are both grounded. The other end of resistor R13 is connected to one end of capacitor C4, and the other end of capacitor C4 is connected to the chip U3. Pin 5 of chip U3 is connected to one end of capacitor C100 and the power conversion circuit, with the other end of capacitor C100 grounded; pin 4 of chip U3 is connected to one end of resistor R25A, one end of resistor R25C, and one end of resistor R26A, with the other ends of resistors R25A, R25C, and R26A all grounded; pin 6 of chip U3 is connected to one end of resistor R54 and one end of capacitor C51, with the other end of resistor R54 connected to a 12V power supply and the other end of capacitor C51 grounded; pin 7 of chip U3 is connected to one end of capacitor C8 and a 3-0V power supply, with the other end of capacitor C8 grounded; pin 8 of chip U3 is grounded.

[0010] In the aforementioned microcontroller-free automatic dimming control circuit for a night light, the power conversion circuit includes an inductor L2. One end of the inductor L2 is connected to the other end of capacitor C4 and the positive terminal of diode D2. The negative terminal of diode D2 is connected to one end of electrolytic capacitor EC1, one end of electrolytic capacitor EC2, one end of resistor R5, and pin 2 of common-mode inductor LF2. The other end of the inductor L2 is connected to the other end of capacitor EC2, the other end of resistor R5, one end of ceramic capacitor CY5, and pin 3 of common-mode inductor LF2. The other end of ceramic capacitor CY5 is grounded. Pin 1 of common-mode inductor LF2 is connected to the positive terminal of the LED, and pin 4 of common-mode inductor LF2 is connected to the negative terminal of the LED.

[0011] In the aforementioned microcontroller-free automatic dimming control circuit for nightlights, the auxiliary power supply circuit is a 12V power supply.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] This novel microcontroller-free automatic dimming control circuit for nightlights enables functional switching without a microcontroller. Traditional nightlights require manual on / off switching, and this circuit, with its dual dimming mode, can detect the ambient light intensity in real time for more linear and reasonable dimming. Furthermore, it adjusts its brightness according to light conditions, turning on at maximum brightness in the evening and reaching its minimum dimming value late at night, thus better aligning with human comfort. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the microcontroller-free automatic dimming control circuit for a night light.

[0015] Figure 2 This is a schematic diagram of the circuit structure of the microcontroller-free automatic dimming control circuit for a night light.

[0016] Figure 3 This is a schematic diagram of the circuit structure of the light detection circuit of this utility model.

[0017] Figure 4 This is a schematic diagram of the circuit structure of the rectifier and filter circuit of this utility model.

[0018] Figure 5 This is a schematic diagram of the circuit structure of the dimming signal circuit of this utility model.

[0019] Figure 6 This is a schematic diagram of the power conversion circuit of this utility model.

[0020] Figure 7 This is a schematic diagram of the LED driver circuit of this utility model.

[0021] In the diagram: 1. Light detection circuit; 2. Rectifier and filter circuit; 3. Dimming signal circuit; 4. Power conversion circuit; 5. LED driver circuit; 6. Auxiliary power supply circuit; 7. Lamp. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] It should be noted that in the description of this utility model, the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. The terms "first," "second," and similar words used in the description of this utility model do not indicate any order, quantity, or importance, but are only used to distinguish different components, and therefore should not be construed as limiting this utility model.

[0024] Furthermore, it should be understood that, for ease of description, the dimensions of the individual components shown in the accompanying drawings are not drawn to actual scale; for example, the thickness or width of some layers may be exaggerated relative to other layers.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined or described in one figure, it will not need to be discussed or described in detail in the description of the subsequent figures.

[0026] Figure 1 This is an overall structural diagram of the microcontroller-free automatic dimming control circuit for a night light. The diagram shows the illumination detection circuit 1, rectifier and filter circuit 2, dimming signal circuit 3, power conversion circuit 4, LED driver circuit 5, and auxiliary power supply circuit 6 of the microcontroller-free automatic dimming control circuit.

[0027] like Figure 1-7As shown, the rectifier and filter circuit is connected to the power conversion circuit, the power conversion circuit is connected to the LED driver circuit and the auxiliary power supply circuit, the auxiliary power supply circuit is connected to the dimming signal circuit and the light detection circuit, the light detection circuit is connected to the dimming signal circuit and the LED driver circuit, the dimming signal circuit is connected to the LED driver circuit, and the LED driver circuit is connected to the lamp.

[0028] Furthermore, the light detection circuit includes chip U4, which is an LM2904 chip. Pin 1 of chip U4 is connected to one end of resistor R11, the other end of resistor R11 is connected to a 3-0V power supply, one end of resistor R112 is connected to ground, and the other end of resistor R112 is grounded. Pin 2 of chip U4 is connected to one end of resistor R109 and one end of resistor R110, the other end of resistor R109 is connected to pin 1 of chip U4 and a 6-0V power supply. Pin 3 of chip U4 is connected to one end of resistor R106 and one end of resistor R108, the other end of resistor R106 is grounded, and the other end of resistor R108 is connected to a 6V power supply. Pin 4 of chip U4 is grounded. Pin 5 of chip U4 is connected to resistor R10... One end of resistor R103 is connected to pin 4, the other end of resistor R104 is grounded, the other end of resistor R103 is connected to the positive terminal of diode D100, the emitter of transistor, one end of resistor R101, one end of resistor R102, one end of capacitor C110, and the 3-0V power supply. The other ends of resistor R101, resistor R102, and capacitor C110 are all grounded. The collector of transistor is connected to the negative terminal of LED2 and the +12V power supply, the base of transistor is connected to the positive terminal of LED2, and the negative terminal of diode D100 is connected to the dimming signal circuit. Pin 6 of chip U4 is connected to the other end of resistor R110 and pin 7 of chip U4. Pin 8 of chip U4 is connected to the 12V power supply.

[0029] Furthermore, the rectifier and filter circuit includes an electrolytic capacitor EC1. One end of the electrolytic capacitor EC1 is connected to the positive input terminal of the power supply, one end of the electrolytic capacitor EC7, one end of the electrolytic capacitor C101, one end of the resistor R6, and the power conversion circuit. The other ends of the electrolytic capacitor EC1, EC7, C101, and R6 are all grounded.

[0030] Furthermore, the dimming signal circuit includes chip U5, which is an LM2904 chip. Pin 1 of chip U5 is connected to one end of resistor R99, and the other end of resistor R99 is connected to the LED driver circuit. Pin 2 of chip U5 is connected to one end of resistor R93, one end of capacitor C90, and a 1.75-3V power supply, with the other end of capacitor C90 grounded. Pin 3 of chip U5 is connected to one end of resistors R96, R97, and R98, and a 2-9.2V power supply. The other end of resistor R96 is connected to a 6V power supply, and the other end of resistor R97... The circuit is grounded; the other end of resistor R98 is connected to the negative terminal of diode D100; pin 4 of chip U5 is grounded; pin 5 of chip U5 is connected to one end of resistor R95, one end of resistor R91, and one end of resistor R92, with the other end of resistor R92 grounded; the other end of resistor R91 is connected to the +12V power supply; pin 6 of chip U5 is connected to one end of resistor R93, with the other end of resistor R93 connected to one end of resistor R94, the other end of resistor R95, and pin 7 of chip U5, with the other end of resistor R94 connected to the +12V power supply; pin 8 of chip U5 is connected to the +12V power supply.

[0031] Furthermore, the power conversion circuit includes an inductor L2. One end of the inductor L2 is connected to the other end of the capacitor C4 and the positive terminal of the diode D2. The negative terminal of the diode D2 is connected to one end of the electrolytic capacitor EC1, one end of the electrolytic capacitor EC2, one end of the resistor R5, and pin 2 of the common-mode inductor LF2. The other end of the inductor L2 is connected to the other end of the capacitor EC2, the other end of the resistor R5, one end of the ceramic capacitor CY5, and pin 3 of the common-mode inductor LF2. The other end of the ceramic capacitor CY5 is grounded. Pin 1 of the common-mode inductor LF2 is connected to the positive terminal of the LED, and pin 4 of the common-mode inductor LF2 is connected to the negative terminal of the LED.

[0032] Furthermore, the LED driving circuit includes a chip U3, which is an OB3379AZ chip. Pin 1 of chip U3 is connected to one end of capacitor C10, and the other end of capacitor C10 is grounded. Pin 2 of chip U3 is connected to one end of capacitor C9, one end of resistor R56, and the other end of resistor R99. The other ends of capacitor C9 and capacitor R56 are grounded. Pin 3 of chip U3 is connected to one end of capacitor C6, one end of resistor R18, and one end of resistor R13. The other ends of capacitor C6 and resistor R18 are both grounded. The other end of resistor R13 is connected to one end of capacitor C4, and the other end of capacitor C4 is connected to the chip U3. Pin 5 of chip U3 is connected to one end of capacitor C100 and the power conversion circuit, while the other end of capacitor C100 is grounded; pin 4 of chip U3 is connected to one end of resistor R25A, one end of resistor R25C, and one end of resistor R26A, while the other ends of resistors R25A, R25C, and R26A are all grounded; pin 6 of chip U3 is connected to one end of resistor R54 and one end of capacitor C51, while the other end of resistor R54 is connected to the 12V power supply, and the other end of capacitor C51 is grounded; pin 7 of chip U3 is connected to one end of capacitor C8 and the 3-0V power supply, while the other end of capacitor C8 is grounded; pin 8 of chip U3 is grounded.

[0033] Specifically, during daylight, the phototransistor LED2 generates leakage current. Through the resistance ratio of resistors R101 and R102, it generates a voltage V1 = 0-9V. This voltage then flows through a voltage follower formed by pins 567 of chip U4, outputting to the inverting input of the U4 subtractor, generating a voltage V2 = 0-6V. The subtractor is set to a fixed 6V, so the ADIM pin of chip U3 can receive a voltage signal of V3 = 3-0V. This pin is the analog dimming pin, starting to operate at 0.8V and reaching maximum dimming at 2.5V. Therefore, during the day, the ADIM pin is below 0.8V, in standby mode. As darkness begins to fall, the current flowing through the phototransistor decreases, and the voltage V1 begins to decrease.

[0034] Node 1: When V1 decreases to 5.25V and V2 is 3.5V, V3 simultaneously increases and gradually rises to 2.5V, reaching the maximum dimming rate, and remains in the maximum dimming state thereafter. Then V6 is 4V. The triangular wave generator composed of pins 5, 6, and 7 of chip U5 will continuously output a triangular wave of V5 voltage from 1.75V to 3V to the comparator composed of pins 1, 2, and 3 for comparison. The comparator continuously outputs a high level, indicating maximum load capacity.

[0035] Node 2: When V1 gradually decreases to 3.55V, V6 equals 3V, and the comparator critically begins to operate. At this time, V4 is 3.67V, and the entire system is in the critical maximum load state. Node 3: When V1 gradually decreases to 2.7V, since D100 is in the critical non-conducting state, V6 equals 2.4V, and the comparator critically outputs a PWM wave with a 52% duty cycle. This is the minimum load state for the entire machine at night.

[0036] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A microcontroller-free automatic dimming control circuit for a night light, characterized in that, include: The system includes a rectifier and filter circuit, a power conversion circuit connected to the rectifier and filter circuit, an LED driver circuit and an auxiliary power supply circuit connected to the power conversion circuit, a dimming signal circuit and a light detection circuit connected to the auxiliary power supply circuit, the light detection circuit being connected to the dimming signal circuit and the LED driver circuit, the dimming signal circuit being connected to the LED driver circuit, and the LED driver circuit being connected to the lamp.

2. The microcontroller-free automatic dimming control circuit for a night light according to claim 1, characterized in that, The light detection circuit includes a chip U4 and a transistor. Pin 1 of chip U4 is connected to one end of resistor R11, the other end of which is connected to a 3-0V power supply, one end of resistor R112, and the other end of resistor R112 is grounded. Pin 2 of chip U4 is connected to one end of resistor R109 and one end of resistor R110, the other end of which is connected to pin 1 of chip U4 and a 6-0V power supply. Pin 3 of chip U4 is connected to one end of resistor R106 and one end of resistor R108, the other end of which is grounded, and the other end of which is connected to a 6V power supply. Pin 4 of chip U4 is grounded. Pin 5 of chip U4 is connected to one end of resistor R104 and one end of resistor R103. The circuit consists of three terminals: one terminal of resistor R104 is grounded, the other terminal of resistor R103 is connected to the anode of diode D100, the emitter of transistor, one end of resistor R101, one end of resistor R102, one end of capacitor C110, and a 3-0V power supply; the other ends of resistor R101, resistor R102, and capacitor C110 are all grounded; the collector of transistor is connected to the cathode of LED2 and a +12V power supply; the base of transistor is connected to the anode of LED2; and the cathode of diode D100 is connected to the dimming signal circuit. Pin 6 of chip U4 is connected to the other end of resistor R110, and pin 7 of chip U4 is connected to the circuit. Pin 8 of chip U4 is connected to a 12V power supply.

3. The microcontroller-free automatic dimming control circuit for a night light according to claim 2, characterized in that, The rectifier and filter circuit includes an electrolytic capacitor EC1. One end of the electrolytic capacitor EC1 is connected to the positive input terminal of the power supply, one end of the electrolytic capacitor EC7, one end of the electrolytic capacitor C101, one end of the resistor R6, and the power conversion circuit. The other ends of the electrolytic capacitor EC1, the electrolytic capacitor EC7, the electrolytic capacitor C101, and the resistor R6 are all grounded.

4. The microcontroller-free automatic dimming control circuit for a night light according to claim 3, characterized in that, The dimming signal circuit includes chip U5. Pin 1 of chip U5 is connected to one end of resistor R99, and the other end of resistor R99 is connected to the LED driver circuit. Pin 2 of chip U5 is connected to one end of resistor R93, one end of capacitor C90, and a 1.75-3V power supply, and the other end of capacitor C90 is grounded. Pin 3 of chip U5 is connected to one end of resistors R96, R97, and R98, and a 2-9.2V power supply. The other end of resistor R96 is connected to a 6V power supply, and the other end of resistor R97... The other end is grounded, and the other end of resistor R98 is connected to the negative terminal of diode D100; pin 4 of chip U5 is grounded; pin 5 of chip U5 is connected to one end of resistor R95, one end of resistor R91, and one end of resistor R92, the other end of resistor R92 is grounded, and the other end of resistor R91 is connected to a +12V power supply; pin 6 of chip U5 is connected to one end of resistor R93, the other end of resistor R93 is connected to one end of resistor R94, the other end of resistor R95, and pin 7 of chip U5, the other end of resistor R94 is connected to a +12V power supply; pin 8 of chip U5 is connected to a +12V power supply.

5. The microcontroller-free automatic dimming control circuit for a night light according to claim 4, characterized in that, The LED driving circuit includes a chip U3. Pin 1 of chip U3 is connected to one end of capacitor C10, and the other end of capacitor C10 is grounded. Pin 2 of chip U3 is connected to one end of capacitor C9, one end of resistor R56, and the other end of resistor R99. The other ends of capacitor C9 and capacitor R56 are grounded. Pin 3 of chip U3 is connected to one end of capacitor C6, one end of resistor R18, and one end of resistor R13. The other ends of capacitor C6 and resistor R18 are both grounded. The other end of resistor R13 is connected to one end of capacitor C4. The other end of capacitor C4 is connected to pin 5 of chip U3 and one end of capacitor C100. The capacitor C100 is connected to the power conversion circuit, and the other end of the capacitor C100 is grounded. Pin 4 of the chip U3 is connected to one end of resistor R25A, one end of resistor R25C, and one end of resistor R26A. The other ends of resistor R25A, R25C, and R26A are all grounded. Pin 6 of the chip U3 is connected to one end of resistor R54 and one end of capacitor C51. The other end of resistor R54 is connected to a 12V power supply, and the other end of capacitor C51 is grounded. Pin 7 of the chip U3 is connected to one end of capacitor C8 and a 3-0V power supply. The other end of capacitor C8 is grounded. Pin 8 of the chip U3 is grounded.

6. The microcontroller-free automatic dimming control circuit for a night light according to claim 5, characterized in that, The power conversion circuit includes an inductor L2. One end of the inductor L2 is connected to the other end of the capacitor C4 and the positive terminal of the diode D2. The negative terminal of the diode D2 is connected to one end of the electrolytic capacitor EC1, one end of the electrolytic capacitor EC2, one end of the resistor R5, and pin 2 of the common-mode inductor LF2. The other end of the inductor L2 is connected to the other end of the capacitor EC2, the other end of the resistor R5, one end of the ceramic capacitor CY5, and pin 3 of the common-mode inductor LF2. The other end of the ceramic capacitor CY5 is grounded. Pin 1 of the common-mode inductor LF2 is connected to the positive terminal of the LED, and pin 4 of the common-mode inductor LF2 is connected to the negative terminal of the LED.

7. A microcontroller-free automatic dimming control circuit for a night light according to claim 1, 2, 3, 4, 5, or 6, characterized in that, The auxiliary power supply circuit is a 12V power supply.

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