Circuit for improving endurance of constant-flow solar lamp

Abstract

The circuit comprises a constant current driver U4, a first pin of the constant current driver U4 is respectively connected with a positive electrode end BTA + of a storage battery U2 and one end of a resistor R4, the other end of the resistor R4 is connected with a positive electrode end of a light source LED, a negative electrode end of the light source LED is connected with a fourth pin of the constant current driver U4, and the other end of the resistor R4 is connected with a positive electrode end BTA + of the storage battery U2. A pin 2 of the constant current driver U4 is connected with a PWM pin of the main control chip U1, a VCC pin of the main control chip U1 is connected with a positive electrode end BTA + of the storage battery U2, the positive electrode end BTA + of the storage battery U2 is connected with a positive electrode end V + of the photovoltaic panel U3, and a negative electrode end BTA-of the storage battery U2 is connected with a negative electrode end V-of the photovoltaic panel U3. According to the utility model, the lamp works in a constant-current mode at the initial stage of lighting, and the output current value is slowly reduced and the working brightness of the lamp is reduced along with the reduction of the output voltage of the storage battery U2 at the later stage of lighting, so that the effect of prolonging the endurance of the lamp is achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of solar lamps, and particularly relates to a circuit for improving the endurance of a constant lumen solar lamp. Background Art

[0002] Currently, the global market has an increasing demand for solar lamps. They are not only for energy saving, but also for portable lighting. There is no need for professional electricians to install the lamps, which can greatly improve convenience.

[0003] There are several types of solar lamps on the market:

[0004] 1. By connecting a resistive load in series with the lamp bead and switching the lamp through the MOS tube, this type of solar lamp will continuously reduce the lamp bead current as the battery voltage decreases, thereby continuously reducing the lamp lumen value and failing to meet the constant lumen lighting requirements.

[0005] 2. By using a professional DCDC boost chip, a constant current effect is achieved. However, this working method cannot take into account the problem that the lighting brightness demand decreases and the battery life demand increases in the later stage of the lamp operation.

[0006] Therefore, a circuit is needed to improve the battery life of constant lumen solar lamps. The circuit can make the lamp work in constant lumen mode at the beginning of lighting. In the later stage of lighting, as the battery voltage decreases, the output current value is slowly reduced, the working brightness of the lamp is reduced, and the battery life of the lamp is increased. Utility Model Content

[0007] The purpose of this utility model is to provide a circuit for improving the battery life of a constant lumen solar lamp, thereby solving the problems mentioned in the above background technology. The circuit provided by this utility model has the characteristics of making the lamp operate in constant lumen mode in the early stage of lighting. In the later stage of lighting, as the battery voltage decreases, the output current value is gradually reduced, reducing the operating brightness of the lamp, thereby achieving the effect of increasing the battery life of the lamp.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a circuit for improving the battery life of a constant lumen solar lamp, comprising a constant current driver U4, wherein pin 1 of the constant current driver U4 is connected to one end of a resistor R1, the other end of the resistor R1 is respectively connected to the positive terminal BTA+ of a battery U2 and one end of a resistor R4, the other end of the resistor R4 is connected to the positive terminal of a light source LED, the negative terminal of the light source LED is connected to pin 4 of the constant current driver U4, pin 2 of the constant current driver U4 is connected to the PWM pin of a main control chip U1, the VCC pin of the main control chip U1 is connected to the positive terminal BTA+ of the battery U2, the positive terminal BTA+ of the battery U2 is connected to the positive terminal V+ of the photovoltaic panel U3, the negative terminal BTA- of the battery U2 is connected to the negative terminal V- of the photovoltaic panel U3, and pin 8 of the constant current driver U4 and the GND pin of the main control chip U1 are respectively connected to the negative terminal BTA- of the battery U2.

[0009] Furthermore, the model of the constant current driver U4 is OC7140.

[0010] For voltage stabilization and filtering, a capacitor C1 is further connected between the positive terminal BTA+ of the battery U2 and the negative terminal BTA- of the battery U2.

[0011] For voltage stabilization and filtering, a capacitor C2 is further connected between the positive terminal BTA+ of the battery U2 and the negative terminal BTA- of the battery U2.

[0012] For voltage stabilization and filtering, a capacitor C3 is further connected between pin 1 of the constant current driver U4 and the negative terminal BTA- of the battery U2.

[0013] In order to detect the output voltage of the photovoltaic panel U3, it further includes a resistor R5 and a resistor R6 connected in series, wherein one end of the resistor R5 is connected to the positive terminal V+ of the photovoltaic panel U3, one end of the resistor R6 is connected to the negative terminal BTA- of the battery U2, and the connection end of the resistor R5 and the resistor R6 is connected to the AD pin of the main control chip U1.

[0014] To set the output current, a sampling resistor is further included. One end of the sampling resistor is connected to pins 5 and 6 of the constant current driver U4, respectively, and the other end of the sampling resistor is connected to the negative terminal BTA- of the battery U2. The sampling resistor includes resistors R2 and R3 connected in parallel.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. The present invention is provided with a constant current driver U4 and a resistor R4. When the output voltage of the battery U2 is higher than the set threshold, the constant current driver U4 continuously outputs a constant current. When the output voltage of the battery U2 is lower than the set threshold, as the output voltage of the battery U2 decreases, the constant current driver U4 reduces the output current, thereby achieving the constant lumen mode in the initial stage of the lamp lighting. In the later stage of the lamp lighting, as the output voltage of the battery U2 decreases, the output current value is gradually reduced, reducing the working brightness of the lamp, thereby achieving the effect of increasing the lamp life.

[0017] 2. The present invention can set the output voltage threshold of the battery U2 by changing the resistance value of the resistor R4 during the design phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the circuit diagram of the utility model; DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] Example 1

[0021] See also Figure 1 The utility model provides the following technical solutions: a circuit for improving the battery life of a constant lumen solar lamp, including a constant current driver U4, the model of which is OC7140, the 1st pin of the constant current driver U4 is connected to one end of the resistor R1, the other end of the resistor R1 is respectively connected to the positive terminal BTA+ of the battery U2 and one end of the resistor R4, the other end of the resistor R4 is connected to the positive terminal of the light source LED, the negative terminal of the light source LED is connected to the 4th pin of the constant current driver U4, and the 2nd pin of the constant current driver U4 is connected to the main control The PWM pin of the chip U1 is connected, the VCC pin of the main control chip U1 is connected to the positive terminal BTA+ of the battery U2, the positive terminal BTA+ of the battery U2 is connected to the positive terminal V+ of the photovoltaic panel U3, the negative terminal BTA- of the battery U2 is connected to the negative terminal V- of the photovoltaic panel U3, the 8th pin of the constant current driver U4 and the GND pin of the main control chip U1 are respectively connected to the negative terminal BTA- of the battery U2, the model of the main control chip U1 is HC89F0312, and the resistance value of the resistor R4 in this embodiment is preferably 1Ω.

[0022] Specifically, without resistor R4, the current at the LED end is constant until the voltage of battery U2 is no longer sufficient to meet the set current output of the LED. When this condition is not met, the battery U2 is already depleted. However, with resistor R4, we limit the current through resistor R4, preventing the voltage at the LED end from meeting this condition in advance. At this time, the battery U2 voltage is still high, and the battery U2 has sufficient charge, allowing the discharge time to be increased at this current.

[0023] It is known that the lamp voltage is 2.7V and the current is set to 1A. Assume that the output current starts to decrease when the output voltage of battery U2 is lower than 3.8V. The calculation formula of the resistance value of resistor R4 is: 3.8V-2.7V / 1A=1.1Ω.

[0024] By adopting the above technical solution, the utility model sets a constant current driver U4 and a resistor R4. When the output voltage of the battery U2 is higher than the set threshold, the constant current driver U4 continues to output a constant current. When the output voltage of the battery U2 is lower than the set threshold, as the output terminal voltage of the battery U2 decreases, the constant current driver U4 reduces the output current, thereby realizing that the lamp works in a constant lumen mode at the initial stage of lighting. In the later stage of lighting, as the output voltage of the battery U2 decreases, the output current value is slowly reduced, and the working brightness of the lamp is reduced, thereby achieving the effect of increasing the battery life of the lamp. The utility model can set the output voltage threshold of the battery U2 by changing the resistance value of the resistor R4 during the design stage.

[0025] Specifically, capacitor C1 is connected between the positive terminal BTA+ and the negative terminal BTA- of battery U2. Capacitor C2 is connected between the positive terminal BTA+ and the negative terminal BTA- of battery U2. Capacitor C3 is connected between pin 1 of constant current driver U4 and the negative terminal BTA- of battery U2.

[0026] The above technical solution is adopted for voltage stabilization and filtering.

[0027] Example 2

[0028] This embodiment differs from Example 1 in that it further includes a sampling resistor. In this embodiment, the sampling resistor preferably has a resistance of 0.1Ω. One end of the sampling resistor is connected to pins 5 and 6 of the constant current driver U4, respectively, and the other end of the sampling resistor is connected to the negative terminal BTA- of the battery U2. The sampling resistor includes resistors R2 and R3 connected in parallel.

[0029] The above technical solution is used to set the output current.

[0030] Example 3

[0031] This embodiment differs from Embodiment 1 in that: specifically, it further includes a resistor R5 and a resistor R6 connected in series, wherein one end of the resistor R5 is connected to the positive terminal V+ of the photovoltaic panel U3, one end of the resistor R6 is connected to the negative terminal BTA- of the battery U2, and the connection end of the resistor R5 and the resistor R6 is connected to the AD pin of the main control chip U1.

[0032] By adopting the above technical solution, the output voltage of the photovoltaic panel U3 is detected. When the output voltage is less than 1V, it is determined to be night time, and when the output voltage is greater than 3V, it is determined to be half a day, thereby realizing the control of lighting.

[0033] To sum up, the utility model is provided with a constant current driver U4 and a resistor R4. When the output voltage of the battery U2 is higher than the set threshold, the constant current driver U4 continuously outputs a constant current. When the output voltage of the battery U2 is lower than the set threshold, as the output terminal voltage of the battery U2 decreases, the constant current driver U4 reduces the output current, thereby realizing that the lamp works in a constant lumen mode at the initial stage of lighting. In the later stage of lighting, as the output voltage of the battery U2 decreases, the output current value is slowly reduced, and the working brightness of the lamp is reduced, thereby achieving the effect of increasing the battery life of the lamp. The utility model can set the output voltage threshold of the battery U2 by changing the resistance value of the resistor R4 during the design stage.

[0034] 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 variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A circuit for improving the endurance of a constant lumen solar lamp, characterized by: It includes a constant current driver U4, where pin 1 of the constant current driver U4 is connected to one end of the resistor R1, the other end of the resistor R1 is respectively connected to the positive terminal BTA+ of the battery U2 and one end of the resistor R4, the other end of the resistor R4 is connected to the positive terminal of the light source LED, the negative terminal of the light source LED is connected to pin 4 of the constant current driver U4, pin 2 of the constant current driver U4 is connected to the PWM pin of the main control chip U1, the VCC pin of the main control chip U1 is connected to the positive terminal BTA+ of the battery U2, the positive terminal BTA+ of the battery U2 is connected to the positive terminal V+ of the photovoltaic panel U3, the negative terminal BTA- of the battery U2 is connected to the negative terminal V- of the photovoltaic panel U3, and pin 8 of the constant current driver U4 and the GND pin of the main control chip U1 are respectively connected to the negative terminal BTA- of the battery U2.

2. The circuit for improving the battery life of a constant lumen solar lamp according to claim 1, characterized in that: The model of the constant current driver U4 is OC7140.

3. The circuit for improving the battery life of a constant lumen solar lamp according to claim 1, characterized in that: A capacitor C1 is connected between the positive terminal BTA+ of the battery U2 and the negative terminal BTA- of the battery U2.

4. The circuit for improving the battery life of a constant lumen solar lamp according to claim 1, characterized in that: A capacitor C2 is connected between the positive terminal BTA+ of the battery U2 and the negative terminal BTA- of the battery U2.

5. The circuit for improving the battery life of a constant lumen solar lamp according to claim 1, characterized in that: A capacitor C3 is connected between pin 1 of the constant current driver U4 and the negative terminal BTA- of the battery U2.

6. The circuit for improving the battery life of a constant lumen solar lamp according to claim 1, characterized in that: It also includes a resistor R5 and a resistor R6 connected in series, wherein one end of the resistor R5 is connected to the positive terminal V+ of the photovoltaic panel U3, one end of the resistor R6 is connected to the negative terminal BTA- of the battery U2, and the connection end of the resistor R5 and the resistor R6 is connected to the AD pin of the main control chip U1.

7. The circuit for improving the battery life of a constant lumen solar lamp according to claim 1, characterized in that: It also includes a sampling resistor, one end of which is connected to pins 5 and 6 of the constant current driver U4 respectively, and the other end of the sampling resistor is connected to the negative terminal BTA- of the battery U2.

8. The circuit for improving the battery life of a constant lumen solar lamp according to claim 7, characterized in that: The sampling resistor includes a resistor R2 and a resistor R3 connected in parallel.

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