Energy-saving and environment-friendly circuit of liquid crystal blackboard and local erasing liquid crystal blackboard

Abstract

The utility model discloses an energy-saving and environment-friendly circuit of a liquid crystal blackboard, and aims to solve the problem that the current liquid crystal blackboard still consumes energy continuously when being not used by people at night. The circuit comprises an environment state sensing circuit, an MCU (Microprogrammed Control Unit) micro-processing control circuit, an infrared touch control circuit, a power switch and conversion circuit and a liquid crystal film driving circuit. A photosensitive sensor and other elements in the environment state sensing circuit are used for sensing the surrounding environment state and converting a data signal into a voltage signal. The MCU micro-processing control circuit receives the voltage signals and judges the environment state so as to control the power supply state of the power switch and the conversion circuit to other circuits. When the ambient light is weak, the system automatically enters a low-power-consumption sleep mode; after dawn, the system automatically recovers to a working state. The design not only is energy-saving and environment-friendly, but also can effectively prolong the service life of the built-in lithium battery.

Description

TECHNICAL FIELD

[0001] The utility model relates to liquid crystal blackboard technical field especially relates to a kind of energy-saving environmental protection circuit and local erasing liquid crystal blackboard of liquid crystal blackboard. BACKGROUND

[0002] At present, most local erasing liquid crystal writing blackboards use adapters or adapter power supply+built-in lithium battery power supply. Although this power supply mode can meet the daily use demand, it still continuously consumes energy when no one uses at night, leading to unnecessary energy waste. In addition, in the case of power cut, the blackboard will automatically consume the energy of built-in lithium battery to maintain standby state, further aggravating the energy consumption problem.

[0003] During the night or no one uses period, these liquid crystal writing blackboards will cause significant electric energy waste due to continuous power supply. Especially in the case of long-term non-use, such as weekends or holidays, this unnecessary energy consumption is particularly prominent. At the same time, when power cut occurs, the blackboard cannot distinguish between day and night, and will still continue to consume the power of built-in lithium battery until the battery is exhausted. This not only increases the maintenance cost, but also shortens the service life of lithium battery. In order to solve these problems, it is necessary to design a circuit system that can intelligently identify ambient light and automatically enter sleep state to reduce unnecessary energy consumption and prolong battery life. SUMMARY

[0004] The main purpose of the utility model is to propose an energy-saving environmental protection circuit of liquid crystal blackboard, aiming at solving the technical problem that the current still continuously consumes energy when no one uses at night.

[0005] The utility model proposes an energy-saving environmental protection circuit of liquid crystal blackboard, which comprises the following components:

[0006] Environment state sensing circuit: through the built-in sensing device to sense the state of the environment around the liquid crystal blackboard. The sensed data signal is converted into a voltage signal. The sensing device contains one or more of photosensitive sensor, temperature sensor, humidity sensor and sound sensor.

[0007] MCU microprocessor control circuit: electrically connected with the environment state sensing circuit. Receive the voltage signal transmitted from the environment state sensing circuit.

[0008] Infrared touch control circuit: electrically connected with the MCU microprocessor control circuit. Provide the coordinate data of the eraser touch position of the liquid crystal blackboard.

[0009] Power switch and conversion circuit: used for controlling power state.

[0010] Liquid crystal film driving circuit: electrically connected with the power switch and conversion circuit. Can drive liquid crystal film to work.

[0011] The MCU micro-processing control circuit discriminates the environment state according to the voltage signal transmitted by the environment state sensing circuit, thereby controlling the power supply switch and conversion circuit to control the power supply state of the infrared touch control circuit and the liquid crystal film driving circuit.

[0012] Further, the environment state sensing circuit further comprises a filter capacitor C74 and a voltage dividing resistor R77, the voltage dividing resistor R77 and the sensing device form a voltage dividing circuit, and the filter capacitor C74 is connected in parallel with the sensing device.

[0013] Further, the infrared touch control circuit comprises a diode D2, a field effect transistor Q10 and a resistor R20, the source of the field effect transistor Q10 is connected to the power supply switch and conversion circuit, and the gate is connected to the MCU micro-processing control circuit.

[0014] Further, the liquid crystal film driving circuit comprises a field effect transistor Q12, a transistor Q13, resistors R21, R24 and R30, and capacitors C43 and C48, the source of the field effect transistor Q12 is connected to the power supply switch and conversion circuit, and the drain is connected to the liquid crystal film driving circuit, the gate of the field effect transistor Q12 is connected to the collector of the transistor Q13, the capacitors C43 and C48 have the effect of soft starting of power supply, which can reduce the voltage peak of switching on and off, the resistor R21 is the pull-up resistor of the field effect transistor Q12, and the resistor R24 is the pull-down resistor of the transistor Q13.

[0015] Further, the power supply switch and conversion circuit comprises a power conversion circuit and an adapter detection circuit, the power conversion circuit comprises diodes D1 and D7, a field effect transistor Q9 and a transistor Q8, and an ICU5 and an inductor L1, the positive pole of the diode D1 is connected to the adapter power supply, the positive pole of the diode D7 is connected to the lithium battery power supply, and the voltage of the adapter power supply is higher than that of the lithium battery power supply in the normal power supply state, the adapter detection circuit comprises a voltage dividing circuit formed by a resistor R19 and a resistor R18 in series connection, and the connection point is input to the MCU micro-processing control circuit after voltage stabilization and filtering by a capacitor C3.

[0016] The application further provides a local erasing liquid crystal blackboard using the energy-saving and environment-friendly circuit of any one of the liquid crystal blackboards.

[0017] Compared with the prior art, the application has the following beneficial effects:

[0018] The utility model discloses a circuit has joined the ambient light sensor circuit, and can determine daytime and night through the sampling and detection of ambient light intensity to MCU microprocessor, and whether the system enters the sleep state is controlled through setting suitable light threshold value, and the system is in normal working condition usually in daytime, and the energy -consuming circuit such as infrared touch control circuit and liquid crystal boost drive circuit is closed under the condition of very dark light in night, and the whole machine system enters the sleep state and the power consumption is low, reaches the energy -conserving and environmental protection and protection and the effect of prolonging built -in lithium battery life, calculates according to 10 hours of night, can save energy and prolong the battery life about 41.67% or so. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is the circuit structure component diagram of energy -conserving and environmental protection circuit of liquid crystal blackboard;

[0020] Figure 2 It is the circuit structure schematic diagram of environmental state induction circuit;

[0021] Figure 3 It is the circuit structure schematic diagram of power conversion circuit;

[0022] Figure 4 It is the circuit structure schematic diagram of adapter detection circuit;

[0023] Figure 5 It is the circuit structure schematic diagram of infrared touch control circuit;

[0024] Figure 6 It is the circuit structure schematic diagram of liquid crystal film drive circuit. DETAILED DESCRIPTION

[0025] The scheme in the embodiments of the utility model will be clearly and completely described below in combination with the drawings in the embodiments of the utility model, and apparently, the described embodiments are only part of the embodiments in the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without creative labor fall within the protection scope of the utility model.

[0026] The utility model discloses a kind of energy -conserving and environmental protection circuit of liquid crystal blackboard, please refer to Figure 1 Circuit structure component diagram, this circuit is mainly applied to partial erasing blackboard energy -conserving and environmental protection and built -in lithium battery protection and prolong life after power grid power failure, mainly by following circuit structure composition:

[0027] The environmental state sensing circuit senses the state of the environment around the liquid crystal blackboard through the built-in sensing device, converts the sensed data signal into a voltage signal, in this embodiment, the sensing device is a photosensitive sensor, which mainly collects light intensity, converts the light signal into a voltage signal, inputs the voltage signal into the MCU for AD conversion, and obtains the light intensity data. Of course, the sensing device can also include one or more of a photosensitive sensor, a temperature sensor, a humidity sensor, and a sound sensor;

[0028] The MCU micro-processing control circuit can perform AD digital-to-analog conversion on the photosensitive sensor signal to obtain the light intensity parameter. The MCU micro-processing control circuit can detect the voltage of the adapter, and can control the power supply or power-off of the infrared touch control circuit and the liquid crystal film boosting and driving circuit at the back end;

[0029] The infrared touch control circuit mainly provides the coordinate data of the board erasing touch to the MCU.

[0030] The power switch and conversion circuit includes a power conversion circuit and an adapter detection circuit. The main power supply is 12V, and the power switch and conversion circuit is provided. After power-off, the lithium battery can provide corresponding power supply. The lithium battery charging circuit is charged by the adapter under normal conditions.

[0031] The liquid crystal film driving circuit is mainly used for driving the liquid crystal film.

[0032] Please refer to Figure 2 , Figure 2 is an environmental state sensing circuit, which is composed of a photosensitive sensor PS1, a capacitor C74 and a resistor R77. R77 is a voltage dividing resistor, and a voltage dividing circuit is formed by connecting the photosensitive sensor PS1 in series. The 2-pin of the photosensitive sensor PS1 is the output pin of the photosensitive sensor. Figure 2For two different connection modes of the environmental state sensing circuit, by adjusting the connection position of the photosensitive sensor and the resistor (R77), different voltage signals can be input to the micro control unit (MCU). Specifically, the photosensitive sensor can be connected above or below the resistor (R77). When the photosensitive sensor is connected above the resistor (R77), in the case of light, the resistance value of the photosensitive sensor decreases, causing the voltage signal input to the MCU to change from low to high; when the photosensitive sensor is connected below the resistor (R77), in the case of light, the resistance value of the photosensitive sensor decreases, causing the voltage signal input to the MCU to change from high to low. Regardless of the connection mode, the MCU can receive and identify the two different voltage change signals. This design improves the flexibility and adaptability of the system, allowing the MCU to accurately identify changes in environmental light and respond accordingly. Taking the case where the photosensitive sensor is connected below the resistor (R77) as an example, C74 is a filter capacitor. During the day or when the light is on, the light is relatively strong, the photosensitive sensor PS1 is in a conducting state after inputting the light to the photosensitive sensor, and the resistor R77 divides a relatively large voltage, so the 2 pin of the photosensitive sensor PS1 will get a relatively low voltage. Conversely, when it is night (lights off), the light is very weak, and very little light is input to the photosensitive sensor, so the photosensitive sensor PS1 is almost in an open circuit state, the resistance is very large, and thus the 2 pin of the photosensitive sensor PS1 will get a relatively high voltage. In this way, different intensities of environmental light get corresponding voltage signals, which are input to the MCU microprocessor control circuit after AD analog-to-digital conversion, and the environmental light data is obtained. By setting appropriate environmental light thresholds, the system can enter a working state or a sleep state.

[0033] Please refer to Figure 3 , Figure 3is a power conversion circuit, by diode D1, D7, field effect tube Q9, triode Q8, ICU5, inductor coil L1, resistance R13, R16, R17, R60, R32, R14, capacitor C12, C22, C21, C24, the positive pole of D1 connects the adapter power supply, the positive pole of D7 connects the lithium battery power supply, in normal power supply state, the voltage of the adapter power supply is higher than that of the lithium battery power supply, so in normal power supply state, the adapter power supply is mainly powered. Q8 and Q9 constitute an electronic switch circuit, the base of Q8 is connected to the MCU control pin through resistance R32, the collector of Q8 is connected to the gate of Q9 through R60, when starting, MCU gives high level through R32, the collector voltage of Q8 becomes low level after Q8 is turned on, so the gate of Q9 becomes low level, thus the drain and source of Q9 are turned on, the input power supply enters the VIN pin of DC to DC IC U5, U5 is a DC to DC conversion IC, which converts the input voltage of the power supply into +5V for MCU and infrared touch control circuit, L1 is an inductor, R14 and R17 are connected in series to form a voltage dividing circuit, the middle connection point inputs the feedback pin of U5 to form a positive feedback circuit, so that the output voltage is constant to +5V, EC3, C22, C21, etc. are input and output capacitors for voltage stabilization and filtering.

[0034] Please refer to Figure 4 , Figure 4 is an adapter detection circuit, which is an adapter 12V voltage detection circuit, mainly for the MCU microprocessor to detect the input voltage value, so as to determine whether the adapter is supplying power or the lithium battery is supplying power. Resistance R19 and resistance R18 are connected in series to form a voltage dividing circuit, and the connection point is input to the GPIO pin of the MCU microprocessor after being stabilized and filtered by capacitor C3. This GPIO pin has an analog to digital (AD) conversion function, and the voltage value of the voltage dividing point can be obtained after AD conversion. If the power grid is disconnected, the adapter will no longer supply power, and the supply voltage VPWR will be supplied by the lithium battery, and a lower voltage relative to the adapter supply voltage (for example: the maximum voltage of the lithium battery is 8.4V, and the voltage of the adapter power supply is 12V) will be obtained at the GPIO port. In this way, the MCU controller knows that the lithium battery is currently supplying power. If the ambient light sensor also detects that the light is very weak in the dark night and reaches the set threshold at the same time, the MCU microprocessor can turn off the power-consuming units, such as the infrared touch control circuit, the liquid crystal boost and driving circuit, and other power-consuming circuits, so as to put the system into sleep state.

[0035] Please refer to Figure 5 and Figure 6 , Figure 5 is an infrared touch control circuit, Figure 6The infrared touch control circuit includes diode D2, field effect transistor Q10, and resistor R20, the source of the field effect transistor Q10 is connected to the power switch and conversion circuit, and the gate is connected to the MCU micro processing control circuit, the liquid crystal film drive circuit includes field effect transistor Q12, triode Q13, resistors R21, R24, R30, capacitors C43, C48, the source of the field effect transistor Q12 is connected to the power switch and conversion circuit, and the drain is connected to the liquid crystal film drive circuit, the gate of the field effect transistor Q12 is connected to the collector of the triode Q13, the capacitors C43 and C48 have the effect of soft starting of power supply at start-up, can reduce the voltage peak of switching on and off, the resistor R21 is the pull-up resistor of the field effect transistor Q12, and the resistor R24 is the pull-down resistor of the Q13.The source of the field effect transistor Q10 is connected to the +5V power supply, the negative electrode of D2 is connected to the infrared IR power supply, the gate of Q10 is connected to a GPIO1 control pin of the MCU, when in the normal power supply state, the GPIO1 pin of the MCU microprocessor outputs low level, the source and the drain of Q10 are turned on, and then the +5V power supply supplies power to the infrared circuit through Q10 and D2; another source of the field effect transistor Q12 is connected to the VCC5 power supply, the drain is connected to the liquid crystal voltage boosting and drive circuit, the gate of Q12 is connected to the collector of the triode Q13, the capacitors C13 and C48 have the effect of soft starting of power supply at start-up, can reduce the voltage peak of switching on and off, the resistor R21 is the pull-up resistor of Q12, and the resistor R24 is the pull-down resistor of Q13.In the normal state, GPIO2 outputs high level through the current limiting resistor R30, the triode Q13 is turned on, the gate of Q12 changes from high to low level, and then the field effect transistor Q12 is in the turned-on normal power supply state, and provides the power supply for the downstream liquid crystal voltage boosting and drive.When the system sleep state is met, the MCU changes GPIO1 from low level to high level, and GPIO2 changes from high level to low level, then the field effect transistors Q10 and Q12 are in the off state, the power consumption of the system is greatly reduced, and the whole machine enters the standby sleep energy-saving state.

[0036] It should be noted that the technical solutions of the various embodiments of the present application can be combined with each other, but must be based on the fact that a person skilled in the art can realize it, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, and is not within the scope of the present application.

[0037] The above-mentioned is only part or preferred embodiment of the present application, neither the text nor the drawings can limit the scope of protection of the present application, any equivalent structural transformation made by using the content of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the scope of protection of the present application.

Claims

1. An energy-saving and environmentally friendly circuit for a liquid crystal blackboard, characterized in that, include: The environmental state sensing circuit uses a built-in sensing device to sense the state of the surrounding environment of the LCD blackboard and converts the sensed data signal into a voltage signal. The MCU microprocessor control circuit is electrically connected to the environmental state sensing circuit, and the MCU microprocessor control circuit receives the voltage signal transmitted from the environmental state sensing circuit. An infrared touch control circuit is electrically connected to the MCU microprocessor control circuit and provides the MCU microprocessor control circuit with coordinate data of the touch position of the blackboard eraser on the LCD blackboard. Power switch and switching circuit, used to control the power supply status; The liquid crystal film driving circuit is electrically connected to the power switch and conversion circuit and can drive the liquid crystal film to work. The MCU microprocessor control circuit determines the environmental state based on the voltage signal transmitted from the environmental state sensing circuit, thereby controlling the power supply state of the power switch and conversion circuit to the infrared touch control circuit and the liquid crystal film driving circuit.

2. The energy-saving and environmentally friendly circuit of the liquid crystal blackboard according to claim 1, characterized in that, The sensing device includes one or more of the following: a photosensitive sensor, a temperature sensor, a humidity sensor, and a sound sensor.

3. The energy-saving and environmentally friendly circuit of the liquid crystal blackboard according to claim 1, characterized in that, The environmental state sensing circuit also includes a filter capacitor C74 and a voltage divider resistor R77. The voltage divider resistor R77 and the sensing device form a voltage divider circuit, and the filter capacitor C74 is connected in parallel with the sensing device.

4. The energy-saving and environmentally friendly circuit of the liquid crystal blackboard according to claim 1, characterized in that, The infrared touch control circuit includes a diode D2, a field-effect transistor Q10, and a resistor R20. The source of the field-effect transistor Q10 is connected to the power switch and conversion circuit, and the gate is connected to the MCU microprocessor control circuit.

5. The energy-saving and environmentally friendly circuit of the liquid crystal blackboard according to claim 1, characterized in that, The liquid crystal film driving circuit includes a field-effect transistor Q12, a transistor Q13, resistors R21, R24, R30, and capacitors C43 and C48. The source of the field-effect transistor Q12 is connected to the power switch and conversion circuit, and the drain is connected to the liquid crystal film driving circuit. The gate of the field-effect transistor Q12 is connected to the collector of the transistor Q13. The capacitors C43 and C48 provide a soft-start function for power-on, which can reduce voltage spikes during power-on and power-off. Resistor R21 is the pull-up resistor for the field-effect transistor Q12, and resistor R24 ​​is the pull-down resistor for the transistor Q13.

6. The energy-saving and environmentally friendly circuit of the liquid crystal blackboard according to claim 1, characterized in that, The power switch and conversion circuit includes a power conversion circuit and an adapter detection circuit.

7. The energy-saving and environmentally friendly circuit of the liquid crystal blackboard according to claim 6, characterized in that, The power conversion circuit includes diodes D1 and D7, MOSFET Q9, transistor Q8, IC5, and inductor L1. The positive terminal of D1 is connected to the adapter power supply, and the positive terminal of D7 is connected to the lithium battery power supply. Under normal power supply conditions, the voltage of the adapter power supply is higher than that of the lithium battery power supply.

8. The energy-saving and environmentally friendly circuit of the liquid crystal blackboard according to claim 6, characterized in that, The adapter detection circuit consists of a voltage divider circuit composed of resistors R19 and R18 connected in series. The voltage is then regulated and filtered by capacitor C3 before being input to the MCU microprocessor control circuit.

9. A partially erasable liquid crystal blackboard, characterized in that, The energy-saving and environmentally friendly circuit of the liquid crystal blackboard as described in any one of claims 1-8.

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