Charging control circuit of photovoltaic clock

Abstract

The utility model discloses a charging control circuit of a photovoltaic clock, which relates to the technical field of motor protection and comprises a circuit board with a plurality of connection interfaces and a charging control circuit arranged on the circuit board. The charging control circuit comprises a voltage regulating circuit and a charging circuit, the input end of the voltage regulating circuit is connected with the solar panel through a charging interface, and the voltage regulating circuit is used for regulating input voltage to a preset voltage range; the output end of the voltage adjusting circuit is electrically connected with the input end of the charging circuit, the output end of the charging circuit is electrically connected with the storage battery, and the charging circuit is used for controlling the charging process of the storage battery. And the charging voltage can be automatically adjusted, and power supply is automatically cut off when the temperature is too high, so that safe charging is ensured.

Description

Technical Field

[0001] This application relates to the field of motor protection technology, specifically to a charging control circuit for a photovoltaic clock. Background Technology

[0002] Photovoltaic clocks utilize solar panels (photovoltaic cells) to collect solar energy and convert it into electrical energy to power the clock. A solar panel is a semiconductor device that, through special manufacturing, converts solar energy into direct current (DC), with the voltage and current proportional to the intensity of sunlight. The DC output from the solar panel needs to be charged via a charging management circuit. However, existing charging management circuits for photovoltaic clocks lack input voltage regulation, limiting the voltage range of compatible solar panels and making them unsuitable for various application scenarios. Furthermore, they suffer from low charging efficiency, inability to set the output voltage, and potential charging hazards due to excessively high temperatures. Utility Model Content

[0003] In view of this, this application provides a charging control circuit for a photovoltaic clock to solve the problems of existing charging management circuits for photovoltaic clocks, which lack input voltage regulation functions, resulting in a very limited range of compatible solar panel voltage types and failing to adapt well to various application scenarios. Furthermore, these circuits also suffer from low charging efficiency, inability to set the output voltage, and potential charging hazards due to excessively high temperatures.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a charging control circuit for a photovoltaic clock, comprising:

[0005] A circuit board with multiple connection interfaces and a charging control circuit mounted on the circuit board;

[0006] The charging control circuit includes a voltage regulation circuit and a charging circuit. The input terminal of the voltage regulation circuit is connected to the solar panel through the charging interface. The voltage regulation circuit is used to adjust the input voltage to a preset voltage range.

[0007] The output of the voltage regulation circuit is electrically connected to the input of the charging circuit, and the output of the charging circuit is electrically connected to the battery. The charging circuit is used to control the charging process of the battery.

[0008] Furthermore, the voltage regulation circuit includes capacitors C1, C2, and C3, resistors R1 and R2, diode D1, and a voltage regulation chip. One end of capacitor C1 is connected to the IN pin of the voltage regulation chip and the negative terminal of diode D1, and the other end of capacitor C1 is grounded. The ADJ pin of the voltage regulation chip, one end of resistor R1, one end of resistor R2, and one end of capacitor C3 are connected. The other ends of resistor R2 and capacitor C3 are grounded. The other end of resistor R1 is connected to the OUT pin of the voltage regulation chip, the positive terminal of diode D1, and one end of capacitor C2. The other end of capacitor C2 is grounded.

[0009] The voltage regulation circuit allows connection to solar panels of various voltage types. After adjusting the input voltage, it can charge the battery, which is a lithium battery.

[0010] Furthermore, the charging circuit includes a charging management chip U1, a MOSFET Q1, an inductor L1, resistors R3, R4, R5, R6, R7, R8, R9, R10, and R11, capacitors C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10, diodes D2, D3, and D4, LEDs D5, D6, and D7;

[0011] Pin 1 of the charging management chip U1 is connected to one end of capacitor C4. One end of resistor R3, one end of resistor R4, the other end of capacitor C4, the anode of diode D2, and the source of MOSFET Q1 are connected. The other end of resistor R3 is grounded through resistor R5. The other end of resistor R4 is connected to the anodes of LEDs D5 and D6. The cathode of LED D5 is connected to pin 4 of the charging management chip U1. The cathode of LED D6 is connected to pin 5 of the charging management chip U1. The cathode of diode D2 is connected to pin 15 of the charging management chip U1 and one end of capacitor C5. The other end of capacitor C5 and the anode of diode D4 are grounded. The cathode of diode D4, the cathode of diode D3, and one end of inductor L1 are connected. The other end of inductor L1 is connected to one end of resistor R10, one end of resistor R11, and pin 13 of charging management chip U1. The other ends of resistor R10, R11, R8, and capacitor C6 are connected to pin 14 of charging management chip U1. The other end of capacitor C6 is connected to pin 10 of charging management chip U1. The other end of resistor R8 is grounded. Capacitor C7 is connected between pin 11 of charging management chip U1 and ground. One end of resistor R9 is connected to pin 9 of charging management chip U1. The other end of resistor R9 is grounded through capacitor C8. Capacitor C10 is connected between the other end of resistor R10 and ground. The cathode of diode D7 is connected to one end of resistor R6. The anode of diode D7 is grounded.

[0012] The charging circuit can control and adjust the charging voltage and current, and automatically stop charging when the circuit board temperature is too high, ensuring charging safety.

[0013] Furthermore, the charging control circuit also includes a thermal resistor RT, which is connected to one end of a resistor R6 via a connection interface P3, and the other end of the resistor R6 is connected to pin 6 of the charging management chip U1.

[0014] Furthermore, the charging management chip U1 uses the CN3722 model.

[0015] As can be seen from the above technical solution, the advantages of this utility model are:

[0016] This application can automatically adjust the input voltage through a voltage regulation circuit, increasing the voltage range of the solar panel and making it more adaptable. It can also automatically adjust the charging voltage through a charging circuit and use a thermal resistor to detect the circuit board temperature during the charging process. When the temperature is too high, the power supply is automatically cut off to ensure safe charging. At the same time, it can ensure maximum power point tracking, resulting in higher charging efficiency. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0018] Figure 1 This is a schematic diagram of the charging control circuit of a photovoltaic clock according to the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the embodiments and accompanying drawings. Here, the illustrative embodiments and their descriptions are used to explain this application, but are not intended to limit it.

[0021] The photovoltaic clock is equipped with a battery charging circuit. When the battery power is low, the charging circuit automatically charges the battery with electricity provided by the solar panel, thus ensuring the photovoltaic clock's long-term operation. This application provides a charging control circuit for a photovoltaic clock, which can intelligently cool down the clock, is convenient and safe to use, and is relatively inexpensive. (Reference) Figures 1 to 2 The device includes a circuit board with multiple connection interfaces and a charging control circuit mounted on the circuit board. The connection interfaces include P1, P2, P3, and P4. The charging control circuit includes a voltage regulation circuit and a charging circuit. The input terminal of the voltage regulation circuit is connected to the solar panel through the charging interface. P1 and P2 are the charging interfaces. The voltage regulation circuit is used to regulate the input voltage to a preset voltage range.

[0022] The output of the voltage regulation circuit is electrically connected to the input of the charging circuit. The output of the charging circuit is connected to the battery via interface P4. The charging circuit is used to control the charging process of the battery.

[0023] like Figure 1 As shown, the voltage regulation circuit includes capacitors C1, C2, and C3, resistors R1 and R2, diode D1, and a voltage regulation chip. One end of capacitor C1 is connected to the IN pin of the voltage regulation chip and the negative terminal of diode D1, while the other end of capacitor C1 is grounded. The ADJ pin of the voltage regulation chip, one end of resistor R1, one end of resistor R2, and one end of capacitor C3 are connected together, while the other ends of resistor R2 and capacitor C3 are grounded. The other end of resistor R1 is connected to the OUT pin of the voltage regulation chip, the positive terminal of diode D1, and one end of capacitor C2, while the other end of capacitor C2 is grounded.

[0024] The voltage regulator chip used is the LM317, an integrated three-terminal voltage regulator with variable output voltage. The LM317 has three pins: one for input, one for output, and one for voltage regulation. Its output voltage is 1.25-37VDC, maximum input-output voltage difference is 40VDC, and minimum input-output voltage difference is 3VDC. Capacitors C1 and C2 are the filter capacitors connected to ground for the input and output pins of the voltage regulator chip, respectively. Resistors R1 and R2 are adjusted to regulate the output voltage. Diode D1 is used to prevent reverse bias of the voltage regulator chip when the input is low. The voltage output from the output pin is directly connected to the charging circuit. The voltage regulation circuit has two charging interfaces, P1 and P2. Interface P1 can extend the voltage range beyond the input voltage range of the charging circuit, allowing connection to more types of solar panels with different voltages, such as 48V or 60V. Interface P2 can directly connect to solar panels within the input voltage range of the charging circuit. Users can choose the appropriate interface based on their needs.

[0025] In this embodiment, the voltage regulation circuit allows access to solar panels with various voltage ratings. After adjusting the input voltage, the battery, which is a lithium battery, can be charged.

[0026] The charging circuit can control and regulate the charging voltage and current, and automatically stop charging when the circuit board temperature overheats, ensuring charging safety. Figure 1 As shown in the circuit diagram, the charging circuit includes a charging management chip U1, a MOSFET Q1, an inductor L1, resistors R3, R4, R5, R6, R7, R8, R9, R10, and R11, capacitors C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10, diodes D2, D3, and D4, LEDs D5, D6, and D7.

[0027] Specifically, pin 1 of the charging management chip U1 is connected to one end of capacitor C4. One end of resistor R3, one end of resistor R4, the other end of capacitor C4, the anode of diode D2, and the source of MOSFET Q1 are connected. The other end of resistor R3 is grounded through resistor R5. The other end of resistor R4 is connected to the anodes of LEDs D5 and D6. The cathode of LED D5 is connected to pin 4 of the charging management chip U1. The cathode of LED D6 is connected to pin 5 of the charging management chip U1. The cathode of diode D2 is connected to pin 15 of the charging management chip U1 and one end of capacitor C5. The other end of capacitor C5 and the anode of diode D4 are grounded. The cathode of diode D4 is connected to the cathode of diode D3 and one end of inductor L1. The circuit is configured such that the other end of inductor L1 is connected to one end of resistor R10, one end of resistor R11, and pin 13 of charging management chip U1; the other ends of resistors R10, R11, R8, and capacitor C6 are connected to pin 14 of charging management chip U1; the other end of capacitor C6 is connected to pin 10 of charging management chip U1; the other end of resistor R8 is grounded; capacitor C7 is connected between pin 11 of charging management chip U1 and ground; one end of resistor R9 is connected to pin 9 of charging management chip U1; the other end of resistor R9 is grounded through capacitor C8; capacitor C10 is connected between the other end of resistor R10 and ground; the cathode of diode D7 is connected to one end of resistor R6; and the anode of diode D7 is grounded. The charging control circuit also includes a thermistor RT, which is connected to one end of resistor R6 via interface P3, and the other end of resistor R6 is connected to pin 6 of charging management chip U1.

[0028] The charging management chip U1 uses the CN3722, which employs advanced PWM (Pulse Width Modulation) control technology. This enables high-efficiency voltage conversion over a wide input voltage range, helping to extend battery life. Its input voltage range is typically around 2.25–37V, and it features constant current and constant voltage charging modes. When the battery voltage is lower than 66.7% of the set constant voltage charging voltage, it automatically enters trickle charging mode, where the charging current is 15% of the set charging current. When the battery voltage is higher than 66.7% of the set constant voltage charging voltage, it enters constant current charging mode, with the charging current set by an internal reference voltage and an external resistor. Once the battery voltage approaches the constant voltage charging voltage, it enters constant voltage charging mode, gradually reducing the charging current until charging ends. This application uses the CN3722 chip as a maximum power point tracking lithium battery charging management chip. It can charge multiple batteries, with a charging current up to 5A, high charging efficiency, low heat generation, adjustable constant current, and includes charging and full charge indicator lights. The chip also features battery overvoltage and overtemperature protection, as well as charging input undervoltage protection. Resistors R3 and R5 are input resistors, with adjustable MPPT. Different input voltages can be accommodated by adjusting the value of resistor R5 or modifying the value of resistor R3. LEDs D6 and D5 are charging and charging completion indicator lights, respectively. The thermistor connected to the P3 interface is a negative temperature coefficient thermistor. Charging will be shut off when the internal temperature of the lithium battery exceeds a preset level.

[0029] MOSFET Q1 is a PMOS transistor, which, together with diodes D3 and D4, inductor L1, resistors R8, R10, and R11, and the charging management chip U1, forms a step-down circuit. Resistors R10 and R11 can be used to adjust the charging current, and resistor R8 can be adjusted to regulate the output voltage. During overvoltage detection, if the voltage at the BAT pin rises to 1.08 times the constant charging voltage, the internal overvoltage comparator of the chip activates, shutting off the PMOS transistor and temporarily stopping charging until the voltage at the BAT pin returns below the constant charging voltage. During charging, the MOSFET and lithium battery will experience temperature increases. Heat sinks and fans can be placed near the MOSFET and lithium battery according to the circuit layout to achieve temperature control and ensure charging safety.

[0030] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to the embodiments of this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A charging control circuit for a photovoltaic clock, characterized in that, include: A circuit board with multiple connection interfaces and a charging control circuit disposed on the circuit board; The charging control circuit includes a voltage regulation circuit and a charging circuit. The input terminal of the voltage regulation circuit is connected to the solar panel through a charging interface. The voltage regulation circuit is used to adjust the input voltage to a preset voltage range. The output terminal of the voltage regulation circuit is electrically connected to the input terminal of the charging circuit, and the output terminal of the charging circuit is electrically connected to the battery. The charging circuit is used to control the charging process of the battery.

2. The charging control circuit of the photovoltaic clock as described in claim 1, characterized in that, The voltage regulation circuit includes capacitors C1, C2, and C3, resistors R1 and R2, diode D1, and a voltage regulation chip. One end of capacitor C1 is connected to the IN pin of the voltage regulation chip and the negative terminal of diode D1, and the other end of capacitor C1 is grounded. The ADJ pin of the voltage regulation chip, one end of resistor R1, one end of resistor R2, and one end of capacitor C3 are connected. The other ends of resistor R2 and capacitor C3 are grounded. The other end of resistor R1 is connected to the OUT pin of the voltage regulation chip, the positive terminal of diode D1, and one end of capacitor C2, and the other end of capacitor C2 is grounded.

3. The charging control circuit of the photovoltaic clock as described in claim 2, characterized in that, The charging circuit includes a charging management chip U1, a MOSFET Q1, an inductor L1, resistors R3, R4, R5, R6, R7, R8, R9, R10, and R11, capacitors C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10, diodes D2, D3, and D4, LEDs D5, D6, and D7. Pin 1 of the charging management chip U1 is connected to one end of the capacitor C4. One end of the resistor R3, one end of the resistor R4, the other end of the capacitor C4, the anode of the diode D2, and the source of the MOSFET Q1 are connected. The other end of the resistor R3 is grounded through the resistor R5. The other end of the resistor R4 is connected to the anodes of the LEDs D5 and D6. The cathode of the LED D5 is connected to pin 4 of the charging management chip U1, and the cathode of the LED D6 is connected to pin 5 of the charging management chip U1. The negative terminal of diode D2 is connected to pin 15 of the charging management chip U1 and one end of capacitor C5. The other end of capacitor C5 and the positive terminal of diode D4 are grounded. The negative terminal of diode D4 is connected to the negative terminal of diode D3 and one end of inductor L1. The other end of inductor L1 is connected to one end of resistor R10, one end of resistor R11, and pin 13 of the charging management chip U1. The other ends of resistor R10, the other end of resistor R11, one end of resistor R8, and one end of capacitor C6 are connected to pin 14 of the charging management chip U1. The other end of capacitor C6 is connected to pin 10 of the charging management chip U1, the other end of resistor R8 is grounded, capacitor C7 is connected between pin 11 of the charging management chip U1 and ground, one end of resistor R9 is connected to pin 9 of the charging management chip U1, the other end of resistor R9 is grounded through capacitor C8, capacitor C10 is connected between the other end of resistor R10 and ground, the negative terminal of diode D7 is connected to one end of resistor R6, and the positive terminal of diode D7 is grounded.

4. The charging control circuit of the photovoltaic clock as described in claim 3, characterized in that, The charging control circuit also includes a thermal resistor RT, which is connected to one end of a resistor R6 via a connection interface P3, and the other end of the resistor R6 is connected to pin 6 of the charging management chip U1.

5. The charging control circuit of the photovoltaic clock as described in claim 3, characterized in that, The charging management chip U1 is model CN3722.

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