Stepless dimming LED intelligent street lamp

Abstract

The utility model provides a stepless dimming LED intelligent street lamp. The stepless dimming LED intelligent street lamp comprises a control chip, an ambient light detection circuit, a voltage regulation circuit, an LED constant-current control circuit and an LED street lamp LED1, the ambient light detection circuit is used for detecting the current ambient light state of the street lamp, the output end of the ambient light detection circuit is connected to the control chip, the control output end of the control chip is connected to the voltage adjusting circuit, and the control chip outputs a PWM control signal corresponding to the current ambient light to the voltage adjusting circuit according to the ambient light state. The voltage regulation circuit regulates the output voltage to the LED street lamp LED1 according to the PWM control signal, the power input end of the voltage regulation circuit is connected to the output end of the direct-current power supply, the power output end of the voltage regulation circuit is connected to the positive electrode of the LED street lamp LED1, the negative electrode of the LED street lamp LED1 is connected to the input end of the LED constant-current control circuit, and the output end of the LED constant-current control circuit is connected to the output end of the direct-current power supply. And the control input end of the LED constant-current control circuit is connected to the control chip.

Description

Technical Field

[0001] The utility model relates to a street lamp, in particular to a stepless dimming LED intelligent street lamp. Background Art

[0002] Due to its own characteristics, such as stability and long service life, LEDs are widely used in traffic street lamps. In existing traffic street lamps, LED street lamps are all controlled by a cluster control method. This method has the following defects: Although cluster control can work according to the set working requirements, that is, work according to the set brightness, this method has poor adaptability and flexibility. Because in traffic sections, the ambient light in different sections is different. At noon, this gap is smaller because the ambient light brightness is stronger at this time and can meet the traffic lighting needs. However, when evening comes, due to the reduction of ambient light and the influence of tall green plants on the roadside, the difference in the actual ambient light of LED street lamps at different section positions is relatively large. If the same brightness is still used for lighting, at this time, if the brightness is too large, it will cause waste of resources, and if the brightness is too small, it cannot meet the lighting needs of some sections.

[0003] Therefore, in order to solve the above technical problems, it is urgent to propose a new technical means. Content of the Utility Model

[0004] In view of this, the purpose of the utility model is to provide a stepless dimming LED intelligent street lamp, which can adaptively adjust its own lighting brightness according to the actual ambient brightness of the street lamp, can ensure the actual brightness demand, thus ensuring traffic safety, and can also save energy, has strong adaptability, and can adapt to various traffic sections.

[0005] A stepless dimming LED intelligent street lamp provided by the utility model includes a control chip, an ambient light detection circuit, a voltage adjustment circuit, an LED constant current control circuit, and an LED street lamp LED1;

[0006] The ambient light detection circuit is used to detect the ambient light state of the current street lamp. The output end of the ambient light detection circuit is connected to the control chip. The control output end of the control chip is connected to the voltage adjustment circuit. The control chip outputs a PWM control signal corresponding to the current ambient light to the voltage adjustment circuit according to the ambient light state. The voltage adjustment circuit adjusts the output voltage to the LED street lamp LED1 according to the PWM control signal. The power input end of the voltage adjustment circuit is connected to the output end of the DC power supply. The power output end of the voltage adjustment circuit is connected to the positive pole of the LED street lamp LED1. The negative pole of the LED street lamp LED1 is connected to the input end of the LED constant current control circuit. The control input end of the LED constant current control circuit is connected to the control chip.

[0007] Further, the LED constant current control circuit includes a digital potentiometer RP, a resistor R12, a resistor R14, an operational amplifier U1, a resistor R15, a resistor R17, a resistor R18, a capacitor C6, and an NMOS transistor Q2;

[0008] The positive power supply terminal of the digital potentiometer RP is connected to the power supply VCC. The negative power supply terminal of the digital potentiometer RP is connected to one end of the resistor R14 through the resistor R12. The control input terminal of the digital potentiometer RP is connected to the control output terminal of the control chip. The other end of the resistor R14 is grounded. The non-inverting terminal of the operational amplifier U1 is connected to the common connection point between the resistor R12 and the resistor R14. The inverting terminal of the operational amplifier U1 is connected to the source electrode of the NMOS transistor Q2 through the resistor R17. The source electrode of the NMOS transistor Q2 is grounded through the resistor R18. The inverting terminal of the operational amplifier U1 is grounded through the capacitor C6. The output terminal of the operational amplifier U1 is connected to the gate electrode of the NMOS transistor Q2 through the resistor R15. The drain electrode of the NMOS transistor Q2 is connected to the negative electrode of the LED street lamp LED1.

[0009] Further, the LED constant current control circuit further includes a temperature compensation circuit. The temperature compensation circuit includes a resistor R9, a thermistor NTC, a resistor R10, a resistor R13, a resistor R16, a resistor R19, a capacitor C7, and an NMOS transistor Q3;

[0010] One end of the resistor R9 is connected to the power supply VCC. The other end of the resistor R9 is connected to one end of the thermistor NTC through the resistor R10. The other end of the thermistor NTC is grounded. The common connection point between the resistor R9 and the resistor R10 is connected to the drain electrode of the NMOS transistor Q3. The gate electrode of the NMOS transistor Q3 is connected to the common connection point between the thermistor NTC and the resistor R10 through the resistor R13. The gate electrode of the NMOS transistor Q3 is grounded through the capacitor C7. The source electrode of the NMOS transistor Q3 is connected to one end of the resistor R16. The other end of the resistor R16 is grounded through the resistor R19. The common connection point between the resistor R16 and the resistor R19 is used as the output terminal of the temperature compensation circuit and is connected to the gate electrode of the NMOS transistor Q2.

[0011] Further, the ambient light detection circuit includes a resistor R22, a resistor R20, a resistor R21, a photoresistor PR, and an operational amplifier U2;

[0012] One end of the resistor R22 is connected to the power supply VCC. The other end of the resistor R22 is grounded through the photoresistor PR. The common connection point between the resistor R22 and the photoresistor PR is connected to the non-inverting terminal of the operational amplifier U2 through the resistor R20. The inverting terminal of the operational amplifier U2 is connected to the reference voltage Vref. The non-inverting terminal of the operational amplifier U2 is connected to the output terminal of the operational amplifier U2 through the resistor R21. The output terminal of the operational amplifier U2 is used as the output terminal of the ambient light detection circuit and is connected to the control chip.

[0013] Further, the voltage adjustment circuit is a UC3843 chip and its peripheral circuit.

[0014] Further, the control chip is an MT32L083 chip.

[0015] Further, the power supply VCC is provided by an SY8501 chip and its peripheral circuit.

[0016] The beneficial effects of the present utility model: Through the present utility model, it is possible to adaptively adjust its own illumination brightness according to the actual ambient brightness of the street lamp, ensure the actual brightness requirement, thereby ensuring traffic safety, and also being able to save energy, having strong adaptability, and being able to adapt to various traffic sections. Description of the Drawings

[0017] The following further describes the present utility model in conjunction with the drawings and embodiments:

[0018] Figure 1 It is a schematic structural diagram of the present utility model.

[0019] Figure 2 It is a schematic diagram of the LED constant current control circuit of the present utility model.

[0020] Figure 3 It is a schematic diagram of the voltage adjustment circuit of the present utility model.

[0021] Figure 4 It is a schematic diagram of the ambient light detection circuit of the present utility model. Specific Embodiments

[0022] The following further elaborates on the present utility model in detail:

[0023] An infinitely dimmable LED intelligent street lamp provided by the present utility model includes a control chip, an ambient light detection circuit, a voltage adjustment circuit, an LED constant current control circuit, and an LED street lamp LED1;

[0024] The ambient light detection circuit is used to detect the ambient light state of the current street lamp. The output end of the ambient light detection circuit is connected to the control chip. The control output end of the control chip is connected to the voltage adjustment circuit. The control chip outputs a PWM control signal corresponding to the current ambient light to the voltage adjustment circuit according to the ambient light state. The voltage adjustment circuit adjusts the output voltage to the LED street lamp LED1 according to the PWM control signal. The power input end of the voltage adjustment circuit is connected to the output end of the DC power supply. The power output end of the voltage adjustment circuit is connected to the positive pole of the LED street lamp LED1. The negative pole of the LED street lamp LED1 is connected to the input end of the LED constant current control circuit. The control input end of the LED constant current control circuit is connected to the control chip. Through the above structure, each street lamp can adaptively adjust its own illumination brightness according to the actual ambient brightness of the street lamp, can ensure the actual brightness requirement, thus ensuring traffic safety, and can also save energy, with strong adaptability, and can adapt to various traffic sections.

[0025] Among them, the control chip is the MT32L083 chip. Of course, this chip also has corresponding peripheral circuits, which can be built according to its factory specification sheet and will not be elaborated here. The voltage adjustment circuit is the UC3843 chip and its peripheral circuits, specifically as Figure 3 shown. The control chip generates PWM control signals with different duty cycles according to the actual situation of the ambient light. The voltage adjustment circuit works according to this PWM control signal, so as to realize the stepless adjustment of the working voltage of the LED street lamp.

[0026] In this embodiment, the LED constant current control circuit includes a digital potentiometer RP, a resistor R12, a resistor R14, an operational amplifier U1, a resistor R15, a resistor R17, a resistor R18, a capacitor C6, and an NMOS transistor Q2;

[0027] The positive power supply terminal of the digital potentiometer RP is connected to the power supply VCC. The negative power supply terminal of the digital potentiometer RP is connected to one end of the resistor R14 through the resistor R12. The control input terminal of the digital potentiometer RP is connected to the control output terminal of the control chip. The other end of the resistor R14 is grounded. The non-inverting input terminal of the operational amplifier U1 is connected to the common connection point between the resistor R12 and the resistor R14. The inverting input terminal of the operational amplifier U1 is connected to the source electrode of the NMOS transistor Q2 through the resistor R17. The source electrode of the NMOS transistor Q2 is grounded through the resistor R18. The inverting input terminal of the operational amplifier U1 is grounded through the capacitor C6. The output terminal of the operational amplifier U1 is connected to the gate electrode of the NMOS transistor Q2 through the resistor R15. The drain electrode of the NMOS transistor Q2 is connected to the negative electrode of the LED street lamp LED1. A constant current circuit is formed through the above structure. The resistor R18 forms a current detection resistor. Current feedback is carried out through the resistor R17, and then the voltage signals at the non-inverting input terminal and the inverting input terminal of the operational amplifier U1 are compared and controlled, so that Q2 is maintained in a stable on state. Different on states of Q2 correspond to different on resistances, so that the working current of the LED1 can be adjusted. The control chip obtains an actual working voltage and a required working current of the current LED street lamp LED1 according to the current ambient light state. The actual working voltage is realized by the control chip generating a corresponding PWM signal to control the voltage adjustment circuit, while the working current is adjusted by controlling the resistance value of the RP, so that the operational amplifier controls Q2 to work in the corresponding on state to form a constant working current. The digital potentiometer RP can adopt an existing digital potentiometer chip, which will not be elaborated here.

[0028] In this embodiment, the LED constant current control circuit further includes a temperature compensation circuit. The temperature compensation circuit includes a resistor R9, a thermistor NTC, a resistor R10, a resistor R13, a resistor R16, a resistor R19, a capacitor C7, and an NMOS transistor Q3;

[0029] One end of the resistor R9 is connected to the power supply VCC. The other end of the resistor R9 is connected to one end of the thermistor NTC through the resistor R10. The other end of the thermistor NTC is grounded. The common connection point between the resistor R9 and the resistor R10 is connected to the drain of the NMOS transistor Q3. The gate of the NMOS transistor Q3 is connected to the common connection point between the thermistor NTC and the resistor R10 through the resistor R13. The gate of the NMOS transistor Q3 is grounded through the capacitor C7. The source of the NMOS transistor Q3 is connected to one end of the resistor R16. The other end of the resistor R16 is grounded through the resistor R19. The common connection point between the resistor R16 and the resistor R19 is connected to the gate of the NMOS transistor Q2 as the output terminal of the temperature compensation circuit. During the operation of the MOS transistor, its on-resistance is greatly affected by temperature. The higher the temperature, the larger its on-resistance. If temperature compensation is not performed, the control signal output by the operational amplifier U1 cannot make Q2 reach the target impedance state. Although feedback can be performed through R17, in fact, when U1 adjusts the output, the actual on-resistance of Q2 is larger than the output value corresponding to U1 at this time, resulting in the entire constant current circuit clock being in a repeated adjustment process, the current is not stable, and the working brightness of LED1 is also unstable. Therefore, temperature compensation is required. The thermistor NTC is a negative temperature thermistor, which is set near the NMOS transistor to collect the temperature of the NMOS transistor Q2. When the temperature rises, the resistance value of the NTC increases, so that the opening degree of the NMOS transistor becomes larger, the flowing current increases, and then the static operating point of the NMOS transistor Q2 is adjusted, so that the NMOS transistor Q2 can maintain the target current required by LED1 when the temperature rises.

[0030] In this embodiment, the ambient light detection circuit includes a resistor R22, a resistor R20, a resistor R21, a photoresistor PR, and an operational amplifier U2;

[0031] One end of the resistor R22 is connected to the power supply VCC. The other end of the resistor R22 is grounded through the photoresistor PR. The common connection point between the resistor R22 and the photoresistor PR is connected to the non-inverting input terminal of the operational amplifier U2 through the resistor R20. The inverting input terminal of the operational amplifier U2 is connected to the reference voltage Vref (this reference voltage can be set by dividing the voltage of the power supply VCC through a resistor voltage dividing circuit, which is a prior art). The non-inverting input terminal of the operational amplifier U2 is connected to the output terminal of the operational amplifier U2 through the resistor R21. The output terminal of the operational amplifier U2 is connected to the control chip as the output terminal of the ambient light detection circuit. Among them, R20, R21, and U2 form a subtraction circuit. When the difference between the non-inverting input terminal and the inverting input terminal of U2 is less than 0, it indicates that the current ambient light brightness meets the lighting requirements, and the control chip controls the voltage adjustment circuit not to work. When the difference between the non-inverting input terminal and the inverting input terminal is greater than 0, it indicates that the ambient light intensity does not meet the requirements, and the control chip sets the PWM control signal of the output value voltage adjustment circuit according to the difference, so as to set the output voltage value of the voltage adjustment circuit.

[0032] Among them, the power supply VCC is provided after the DC power supply is stepped down by the SY8501 chip and its peripheral circuit.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A stepless dimming LED intelligent street lamp, characterized by: It includes a control chip, an ambient light detection circuit, a voltage adjustment circuit, an LED constant current control circuit and an LED street lamp LED1; The ambient light detection circuit is used to detect the ambient light state of the current street lamp. The output end of the ambient light detection circuit is connected to the control chip. The control output end of the control chip is connected to the voltage adjustment circuit. The control chip outputs a PWM control signal corresponding to the current ambient light to the voltage adjustment circuit according to the ambient light state. The voltage adjustment circuit adjusts the output voltage to the LED street lamp LED1 according to the PWM control signal. The power input end of the voltage adjustment circuit is connected to the output end of the DC power supply. The power output end of the voltage adjustment circuit is connected to the positive electrode of the LED street lamp LED1. The negative electrode of the LED street lamp LED1 is connected to the input end of the LED constant current control circuit. The control input end of the LED constant current control circuit is connected to the control chip.

2. According to claim 1, the stepless dimming LED intelligent street lamp is characterized in that: The LED constant current control circuit includes a digital potentiometer RP, a resistor R12, a resistor R14, an operational amplifier U1, a resistor R15, a resistor R17, a resistor R18, a capacitor C6 and an NMOS tube Q2; The positive power terminal of the digital potentiometer RP is connected to the power supply VCC, the negative power terminal of the digital potentiometer RP is connected to one end of the resistor R14 through the resistor R12, the control input terminal of the digital potentiometer RP is connected to the control output terminal of the control chip, the other end of the resistor R14 is grounded, the in-phase terminal of the operational amplifier U1 is connected to the common connection point between the resistor R12 and the resistor R14, the inverting terminal of the operational amplifier U1 is connected to the source of the NMOS tube Q2 through the resistor R17, the source of the NMOS tube Q2 is grounded through the resistor R18, the inverting terminal of the operational amplifier U1 is grounded through the capacitor C6, the output terminal of the operational amplifier U1 is connected to the gate of the NMOS tube Q2 through the resistor R15, and the drain of the NMOS tube Q2 is connected to the negative electrode of the LED street lamp LED1.

3. The stepless dimming LED intelligent street light according to claim 2 is characterized in that: The LED constant current control circuit also includes a temperature compensation circuit, which includes a resistor R9, a thermistor NTC, a resistor R10, a resistor R13, a resistor R16, a resistor R19, a capacitor C7 and an NMOS tube Q3; One end of the resistor R9 is connected to the power supply VCC, the other end of the resistor R9 is connected to one end of the thermistor NTC through the resistor R10, the other end of the thermistor NTC is grounded, the common connection point between the resistor R9 and the resistor R10 is connected to the drain of the NMOS tube Q3, the gate of the NMOS tube Q3 is connected to the common connection point between the thermistor NTC and the resistor R10 through the resistor R13, the gate of the NMOS tube Q3 is grounded through the capacitor C7, the source of the NMOS tube Q3 is connected to one end of the resistor R16, the other end of the resistor R16 is grounded through the resistor R19, and the common connection point of the resistor R16 and the resistor R19 is connected to the gate of the NMOS tube Q2 as the output end of the temperature compensation circuit.

4. The stepless dimming LED intelligent street light according to claim 1 is characterized in that: The ambient light detection circuit includes a resistor R22, a resistor R20, a resistor R21, a photoresistor PR and an operational amplifier U2; One end of the resistor R22 is connected to the power supply VCC, the other end of the resistor R22 is grounded through the photoresistor PR, the common connection point between the resistor R22 and the photoresistor PR is connected to the in-phase end of the operational amplifier U2 through the resistor R20, the inverting end of the operational amplifier U2 is connected to the reference voltage Vref, the in-phase end of the operational amplifier U2 is connected to the output end of the operational amplifier U2 through the resistor R21, and the output end of the operational amplifier U2 is connected to the control chip as the output end of the ambient light detection circuit.

5. The stepless dimming LED intelligent street light according to claim 1 is characterized in that: The voltage regulating circuit is a UC3843 chip and its peripheral circuits.

6. The stepless dimming LED intelligent street light according to claim 1 is characterized in that: The control chip is MT32L083 chip.

7. The stepless dimming LED intelligent street light according to claim 2, 3 or 4, characterized in that: The power supply VCC is provided by the SY8501 chip and its peripheral circuits.

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