A low-power solar light-controlled boost circuit

Abstract

A low-power solar light-controlled boost circuit includes a chip internal circuit and a peripheral circuit; the peripheral circuit includes an inductor L, a solar panel solar, an input inductor L and an output capacitor Cout; the chip internal circuit includes a boost circuit, a solar charging control circuit, a battery low-power shutdown circuit, an enable circuit and a power supply switching circuit; the solar panel solar is connected between a pin SOL and a ground terminal GND, the input inductor L is connected between a pin BAT and a ground terminal GND, the input inductor L is connected between a pin BAT and a pin LX, and the output capacitor Cout is connected between a power supply VDD and a ground terminal GND. Therefore, the present invention pulls down the output voltage when enabling control and light-controlled charging, thereby greatly saving power consumption and expanding the scope of application.

Description

[0001] The invention belongs to the technical field of lighting circuits and relates to a low-power solar light-controlled boost circuit. Background Art

[0002] In the current environment of promoting green living, outdoor lighting applications such as parks, squares, and outdoor advertising lights have begun to generally use solar energy to supplement energy and control methods, which can not only make full use of current sustainable energy, but also greatly save the consumption of traditional energy and reduce pollution emissions. In actual applications, lawn lights, light strings, and other LEDs often need to be powered by a power supply greater than their conduction voltage, which requires a boost function when using solar cells for power supply.

[0003] The LED controller circuits with boost function widely used in the market mainly include: constant current control circuit, constant voltage control circuit, PWM (pulse width modulation) control circuit, etc.

[0004] Those skilled in the field of solar lighting circuit technology know that when using a solar light-controlled boost circuit constant voltage control circuit, the solar cell boost process will decrease as the solar cell is used, and the power consumption will increase faster and faster due to energy conservation when the constant voltage is applied. When the solar cell power drops to a certain value, the output is turned off. As the output is turned off, the solar cell is called back due to excessive discharge. At this time, the solar light-controlled boost circuit starts working again. This will cause the output to fluctuate after the solar cell power is low, which will become particularly obvious when applied to LEDs, making low battery detection and shutdown particularly important.

[0005] In particular, in solar light-controlled boost applications, when two solar dry cells or lithium batteries are connected in series, the output voltage after solar charging is the same as the input voltage, while the LED conduction voltage is lower than the voltage of the two dry cells and lithium batteries, which will cause the LED to light up during solar charging. This theme is not only inconsistent with customer habits, but also a waste of resources. Therefore, products used in lawn lights, solar light strings, etc. on the market often encounter application limitations and can only be used for solar charging boost applications of one battery without an external shutdown circuit.

[0006] In addition, the traditional solar light-controlled boost circuit is often composed of a boost chip, solar charging control and other circuits. This increases the PCB board area and the number of peripheral tubes in actual application, greatly increasing the actual cost of use. Summary of the invention

[0007] The technical problem to be solved by the present invention is mainly to propose a new low-power solar light-controlled boost circuit, which not only solves the problem of voltage instability in solar charging boost, but also reduces the PCB board area and the number of peripheral tubes, greatly saving power consumption, thereby achieving the purpose of energy conservation and emission reduction.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] A low-power solar light-controlled boost circuit, comprising an internal chip circuit and a peripheral circuit; the peripheral circuit comprises a capacitor, a solar panel solar, an input inductor L and an output capacitor Cout; the internal chip circuit comprises a boost circuit, a solar charging control circuit, a battery low-power shutdown circuit, an enable circuit and a power supply switching circuit; the solar panel solar is connected between a pin SOL and a ground terminal GND, the capacitor is connected between a pin BAT and a ground terminal GND, the input inductor L is connected between a pin BAT and a pin LX, and the output capacitor Cout is connected between a power supply VDD and a ground terminal GND; wherein the signal of the pin BAT and the signal of the pin SOL generate an enable signal EN1 through the solar charging control circuit, and the battery low-power shutdown circuit receives the pin BAT signal to generate a control signal Cout. TL, the input end of the enable circuit receives the signal received by the pin EN and outputs the enable signal EN2, the pin LX signal, the enable signal EN1, the enable signal EN2 and the control signal CTL generate the internal power supply pin vdd1 output signal through the boost circuit and supply it to the power supply switching circuit, the enable signal EN1, the enable signal EN2, the internal power supply pin vdd1 output signal and the ground terminal GND signal generate and output the power supply VDD signal through the power supply switching circuit; when the boost circuit works normally and there is no light-controlled charging, the power supply switching circuit outputs the power supply VDD with the same voltage as the internal power supply pin vdd1, when the boost circuit works in light-controlled charging or the enable is turned off, the power supply switching circuit generates a shutdown signal and outputs the power supply VDD with the same voltage as the ground terminal GND.

[0010] Furthermore, the power supply switching circuit includes a first switch key1, a second switch key2, a NOR gate and an inverter; the two input ends of the NOR gate are respectively connected to the enable signal EN1 and the enable signal EN2, the first switch key1 is connected between the internal power supply pin vdd1 and the power supply VDD signal, and the second switch key2 is connected between the ground terminal GND signal and the power supply VDD signal; the NOR gate controls the conduction of the first switch key1, and the inverter controls the conduction of the first switch key2. When the enable signal EN1 and the enable signal EN2 are turned off, the power supply switching circuit switches the output VDD to the ground terminal GND signal.

[0011] Furthermore, the battery low power shutdown circuit includes a resistor R8, a resistor R9, a resistor R10, a resistor R11, a MOS transistor 3, a MOS transistor 4 and a Schmitt trigger, wherein the resistor R8, the resistor R9 and the resistor R10 are connected in series between the pin BAT and the ground terminal GND in sequence, and the resistor R11 is connected to the internal power supply pin vdd1 and the input terminal of the Schmitt trigger; the gate of the MOS transistor 3 is connected to the connection point of the resistor R8 and the resistor R9, the drain is connected to the input terminal of the Schmitt trigger, and the source is connected to the ground terminal GND; the gate of the MOS transistor 4 is connected to the output terminal of the Schmitt trigger, the drain of the MOS transistor 4 is connected to the connection point of the resistor R9 and the resistor R10, and the source of the MOS transistor 4 is connected to the ground terminal GND; and the output terminal of the Schmitt trigger outputs the control signal CTL.

[0012] Furthermore, the MOS transistor 3 and the MOS transistor 4 are NMOS transistors.

[0013] Furthermore, the boost circuit includes a resistor R1, a resistor R2, a resistor R3, an operational amplifier and a MOS transistor MN0, the resistor R1, the resistor R2 and the resistor R3 are connected in series between the pin BAT and the ground terminal GND in sequence, the positive electrode of the operational amplifier is connected to the pin SOL, the negative electrode of the operational amplifier is connected to the connection point of the resistor R1 and the resistor R2, the drain of the MOS transistor MN0 is connected to the connection point of the resistor R2 and the resistor R3, the source of the MOS transistor MN0 is connected to the ground terminal GND; the gate of the MOS transistor MN0 is connected to the output terminal of the operational amplifier; the output terminal of the operational amplifier outputs the enable signal EN1.

[0014] Furthermore, the solar charging control circuit includes a resistor R4, a resistor R5, an operational amplifier and a MOS transistor MP0, the resistor R4 and the resistor R5 are connected in series between the pin SOL and the ground terminal GND in sequence, the positive electrode of the operational amplifier is connected to the pin BAT, the negative electrode of the operational amplifier is connected to the connection point of the resistor R4 and the resistor R5, the drain of the MOS transistor MP0 is connected to the pin SOL, the source of the MOS transistor MP0 is connected to the pin BAT; the gate of the MOS transistor MP0 is connected to the output end of the operational amplifier.

[0015] It can be seen from the above technical solutions that the low-power solar light-controlled boost circuit of the present invention provides a solution that can effectively solve the problem of solar charging and constant output voltage. The circuit can be used in a wide operating voltage range, and when the supply voltage is higher than the internally set minimum operating threshold voltage, it can ensure that the output voltage is not affected by the supply voltage and always remains unchanged.

[0016] In addition, the present invention provides a constant voltage output mode and adopts a low power consumption design, which ensures the service life of the battery when charging or not connected to the output load, thereby greatly saving energy. An enable shutdown function is added, which can completely shut down the output when the output load is not needed, greatly saving power consumption. At the same time, it also solves the problem of repeated output voltage during the battery shutdown and startup process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure shows a schematic diagram of a module of a low-power solar light-controlled boost circuit according to an embodiment of the present invention.

[0018] Figure 2 The specific circuit diagram of the boost circuit in the embodiment of the present invention is shown as follows:

[0019] Figure 3 The specific circuit diagram of the solar charging circuit in the embodiment of the present invention is shown as follows:

[0020] Figure 4 Schematic diagram of a low-battery shutdown circuit in an embodiment of the present invention

[0021] Figure 5 FIG. 1 is a schematic diagram of a power supply switching circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1-5 , the specific implementation modes of the present invention are further described in detail.

[0023] It should be noted that the present invention is applied to a solar light-controlled boost circuit based on a constant voltage control circuit, and the constant voltage control circuit can be a PWM (pulse width modulation) type control circuit or a PFM (pulse frequency modulation) type control circuit.

[0024] See also Figure 1 , Figure 1 FIG. 1 is a schematic diagram of a module of a low-power solar light-controlled boost circuit according to an embodiment of the present invention. Figure 1 As shown, the low-power solar light-controlled boost circuit includes a chip internal circuit and a peripheral circuit; the peripheral circuit includes a capacitor, a solar panel solar, an input inductor L and an output capacitor Cout; the chip internal circuit includes a boost circuit, a solar charging control circuit, a battery low-power shutdown circuit, an enable circuit and a power supply switching circuit. In other words, the present invention concentrates all functional modules in one chip, which reduces the PCB board area and the number of peripheral tubes in the actual application process. Most importantly, by adding a power supply switching circuit, the present invention can be used in a wider operating voltage range, by adding a battery low-power shutdown circuit, the output can be directly shut down after the solar cell power is low, avoiding the situation where the LED lamp output has high and low brightness, and by adding an enable circuit, the present invention can ensure that the low-power solar light-controlled boost circuit does not work when the user does not need to use the solar LED lamp for a period of time.

[0025] like Figure 1 As shown, in an embodiment of the present invention, the solar panel solar is connected between the pin SOL and the ground terminal GND, the capacitor is connected between the pin BAT and the ground terminal GND, the input inductor L is connected between the pin BAT and the pin LX, and the output capacitor Cout is connected between the power supply VDD and the ground terminal GND; wherein, the signal of the pin BAT and the signal of the pin SOL generate an enable signal EN1 through the solar charging control circuit, the battery low power shutdown circuit receives the pin BAT signal to generate a control signal CTL, the input end of the enable circuit receives the signal received by the pin EN, and outputs an enable signal EN2, the pin LX signal, the enable signal EN1, the enable signal EN2 and the control signal CTL generate the internal power supply pin vdd1 output signal through the boost circuit and supply it to the power supply switching circuit, the enable signal EN1, the enable signal EN2, the internal power supply pin vdd1 output signal and the ground terminal GND signal generate and output the power supply VDD signal through the power supply switching circuit.

[0026] That is to say, in the above embodiment, the information of the internal power supply pin vdd1 and the information of the enable signal EN1 and the enable signal EN2 together determine the output of the low-power solar light-controlled boost circuit; when the boost circuit works normally and there is no light-controlled charging, the power supply switching circuit outputs the power supply VDD which is the same as the voltage of the internal power supply pin vdd1, and when the boost circuit works in light-controlled charging or is enabled to be turned off, the power supply switching circuit generates a shutdown signal, and the output is the same as the voltage of the ground terminal GND.

[0027] See also Figure 2 , Figure 2 FIG. 2 is a schematic diagram of a voltage boost circuit according to an embodiment of the present invention. Figure 2 As shown, the boost circuit includes a resistor R1, a resistor R2, a resistor R3, an operational amplifier and a MOS transistor MN0, wherein the resistor R1, the resistor R2 and the resistor R3 are connected in series between the pin BAT and the ground terminal GND in sequence, the positive electrode of the operational amplifier is connected to the pin SOL, the negative electrode of the operational amplifier is connected to the connection point of the resistor R1 and the resistor R2, the drain of the MOS transistor MN0 is connected to the connection point of the resistor R2 and the resistor R3, the source of the MOS transistor MN0 is connected to the ground terminal GND; the gate of the MOS transistor MN0 is connected to the output terminal of the operational amplifier; and the output terminal of the operational amplifier outputs the enable signal EN1.

[0028] In the embodiment of the present invention, as the light becomes stronger, When the enable signal EN1 is high, the light control signal is detected at this time, which can control the boost circuit to shut down and pull the output power VDD to the ground terminal GND through the power supply switching circuit; as the light becomes weaker, When EN1 is low, the light control signal is detected to be invalid, and the boost circuit and output power supply VDD can be restored. In this circuit, a charging hysteresis is made through the NMOS tube MN0, thereby preventing the critical state encountered during solar charging and discharging.

[0029] See also Figure 3 , Figure 3The specific circuit diagram of the solar charging circuit in the embodiment of the present invention is shown. As shown in the figure, the solar charging control circuit includes a resistor R4, a resistor R5, an operational amplifier and a MOS transistor MP0, the resistor R4 and the resistor R5 are connected in series between the pin SOL and the ground terminal GND in sequence, the positive electrode of the operational amplifier is connected to the pin BAT, the negative electrode of the operational amplifier is connected to the connection point of the resistor R4 and the resistor R5, the drain of the MOS transistor MP0 is connected to the pin SOL, the source of the MOS transistor MP0 is connected to the pin BAT; the gate of the MOS transistor MP0 is connected to the output end of the operational amplifier.

[0030] In an embodiment of the present invention, when When the gate voltage of the PMOS tube MP2 is low, the output information of the pin SOL charges the pin BAT; when When , the gate voltage of PMOS tube MP2 is high, and the charging is completed.

[0031] It can be seen from the above that, through the above circuit, the level values ​​of the pin BAT and the pin SOL can be detected, so as to obtain the result of whether the solar energy is charging the battery, thereby realizing the solar energy charging management function.

[0032] Please see again Figure 1 As shown in the figure, the low-power solar light-controlled boost circuit also includes a battery low-power shutdown circuit, which receives the pin BAT signal to generate a control signal CTL. When the signal of the pin BAT shows that the battery power is insufficient, the power supply switching circuit generates a shutdown signal; wherein, the signal of the pin LX, the enable signal EN1, and the control signal CTL are generated by the boost circuit to generate the internal power supply pin vdd1 signal and supplied to the power supply switching circuit to output the voltage of the power supply VDD or the voltage of the ground terminal GND.

[0033] Please combine Figure 1 See also Figure 4 , Figure 4The schematic diagram of the schematic diagram of the low-battery shutdown circuit in the embodiment of the present invention is shown. The low-battery shutdown circuit includes a resistor R8, a resistor R9, a resistor R10, a resistor R11, a MOS transistor 3, a MOS transistor 4 and a Schmitt trigger. The resistors R8, R9 and R10 are connected in series between the pin BAT and the ground terminal GND in sequence, and the resistor R11 is connected to the internal power supply pin vdd1 and the input terminal of the Schmitt trigger; the gate of the MOS transistor 3 is connected to the connection point of the resistor R8 and the resistor R9, the drain is connected to the input terminal of the Schmitt trigger, and the source is connected to the ground terminal GND; the gate of the MOS transistor 4 is connected to the output terminal of the Schmitt trigger, the drain of the MOS transistor 4 is connected to the connection point of the resistor R9 and the resistor R10, and the source of the MOS transistor 4 is connected to the ground terminal GND; the output terminal of the Schmitt trigger outputs the control signal CTL.

[0034] The working principle of the low-battery shutdown circuit in the above embodiment is to detect the control signal CTL output by the voltage at the BAT pin, and then control the boost circuit and the power supply switching circuit. , V TH_MN3 is the conduction voltage of the NMOS tube MN3, at this time the output control signal CTL is low; as the battery works, its supply voltage gradually decreases. When the output control signal CTL is high, the boost circuit and output voltage are controlled by detecting the voltage of the pin BAT. When the battery power displayed by the pin BAT is insufficient, the low-power solar light-controlled boost circuit is turned off.

[0035] See also Figure 5 , Figure 5 The schematic diagram of the schematic diagram power supply switching circuit in the embodiment of the present invention is shown. As shown in the figure, the power supply switching circuit includes a first switch key1, a second switch key2, an NOR gate and an inverter; the two input ends of the NOR gate are respectively connected to the enable signal EN1 and the enable signal EN2, the first switch key1 is connected between the internal power supply pin vdd1 and the power supply VDD signal, and the second switch key2 is connected between the ground terminal GND signal and the power supply VDD signal; the NOR gate controls the conduction of the first switch key1, and the inverter controls the conduction of the first switch key2. When the enable signal EN1 and the enable signal EN2 are turned off, the output VDD is switched to the ground terminal GND signal.

[0036] The working principle of the above circuit is that when the boost circuit works normally and there is no light control, the output power supply VDD voltage is the same as the voltage of the internal power supply pin vdd1. When the light control is charged or enabled to be turned off, it outputs the voltage of the ground terminal GND. The output voltage can be effectively turned off by the power supply switching circuit. The above technical solution solves the problem of the boost light control product on the existing market well. When the light control is charged, its output voltage is equal to the input voltage. When the input voltage is greater than the LED conduction threshold voltage, when it is applied to LED related products, the LED will be completely turned off.

[0037] In summary, the present invention can effectively solve the problem encountered by similar products on the market through the power supply switching circuit, which not only expands the width of application scenarios, but also reduces the power consumption of the chip.

[0038] The above-described embodiments are only preferred embodiments of the present invention, and the embodiments are not intended to limit the patent protection scope of the present invention. Therefore, any equivalent structural changes made using the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A low-power solar light-controlled boost circuit, characterized in that: The chip comprises an internal circuit and a peripheral circuit; the peripheral circuit comprises a capacitor, a solar panel solar, an input inductor L and an output capacitor Cout; the internal circuit of the chip comprises a boost circuit, a solar charging control circuit, a battery low power shutdown circuit, an enable circuit and a power supply switching circuit; the solar panel solar is connected between a pin SOL and a ground terminal GND, the capacitor is connected between a pin BAT and a ground terminal GND, the input inductor L is connected between a pin BAT and a pin LX, and the output capacitor Cout is connected between a power supply VDD and a ground terminal GND; wherein the signal of the pin BAT and the signal of the pin SOL are The solar charging control circuit generates an enable signal EN1, the battery low power shutdown circuit receives the pin BAT signal to generate a control signal CTL, the input end of the enable circuit receives the signal received by the pin EN, and outputs an enable signal EN2, the pin LX signal, the enable signal EN1, the enable signal EN2 and the control signal CTL generate an internal power supply pin vdd1 output signal through the boost circuit and supply it to the power supply switching circuit, the enable signal EN1, the enable signal EN2, the internal power supply pin vdd1 output signal and the ground terminal GND signal generate the power supply VDD signal through the power supply switching circuit; When the boost circuit works normally and there is no light-controlled charging, the power supply switching circuit outputs the power supply VDD to be the same as the voltage of the internal power supply pin vdd1. When the boost circuit works in light-controlled charging or is enabled to be turned off, the power supply switching circuit generates a shutdown signal and outputs the power supply VDD to be the same as the voltage of the ground terminal GND. The power supply switching circuit includes a first switch key1, a second switch key2, a NOR gate and an inverter; the two input ends of the NOR gate are respectively connected to the enable signal EN1 and the enable signal EN2, the first switch key1 is connected between the internal power supply pin vdd1 and the power supply VDD signal, and the second switch key2 is connected between the ground terminal GND signal and the power supply VDD signal; the NOR gate controls the conduction of the first switch key1, and the inverter controls the conduction of the first switch key2. When the enable signal EN1 and the enable signal EN2 are turned off, the power supply switching circuit switches the output VDD to the ground terminal GND signal.

2. The low-power solar light-controlled boost circuit according to claim 1; characterized in that: The low battery shutdown circuit includes a resistor R8, a resistor R9, a resistor R10, a resistor R11, a MOS transistor 3, a MOS transistor 4 and a Schmitt trigger. The resistors R8, R9 and R10 are connected in series between the pin BAT and the ground terminal GND in sequence, and the resistor R11 is connected to the internal power supply pin vdd1 and the input terminal of the Schmitt trigger; the gate of the MOS transistor 3 is connected to the connection point of the resistor R8 and the resistor R9, the drain is connected to the input terminal of the Schmitt trigger, and the source is connected to the ground terminal GND; the gate of the MOS transistor 4 is connected to the output terminal of the Schmitt trigger, the drain of the MOS transistor 4 is connected to the connection point of the resistor R9 and the resistor R10, and the source of the MOS transistor 4 is connected to the ground terminal GND; the output terminal of the Schmitt trigger outputs the control signal CTL.

3. The low power consumption solar light-controlled boost circuit according to claim 2, characterized in that: The MOS transistor 3 and the MOS transistor 4 are NMOS transistors.

4. The low-power solar light-controlled boost circuit according to claim 1, characterized in that: The boost circuit includes a resistor R1, a resistor R2, a resistor R3, an operational amplifier and a MOS transistor MN0. The resistors R1, R2 and R3 are connected in series between the pin BAT and the ground terminal GND in sequence. The positive electrode of the operational amplifier is connected to the pin SOL, the negative electrode of the operational amplifier is connected to the connection point between the resistor R1 and the resistor R2, the drain of the MOS transistor MN0 is connected to the connection point between the resistor R2 and the resistor R3, the source of the MOS transistor MN0 is connected to the ground terminal GND; the gate of the MOS transistor MN0 is connected to the output terminal of the operational amplifier; and the output terminal of the operational amplifier outputs the enable signal EN1.

5. The low power consumption solar light-controlled boost circuit according to claim 1, characterized in that: The solar charging control circuit includes a resistor R4, a resistor R5, an operational amplifier and a MOS transistor MP0. The resistor R4 and the resistor R5 are connected in series between the pin SOL and the ground terminal GND in sequence. The positive electrode of the operational amplifier is connected to the pin BAT, the negative electrode of the operational amplifier is connected to the connection point of the resistor R4 and the resistor R5, the drain of the MOS transistor MP0 is connected to the pin SOL, and the source of the MOS transistor MP0 is connected to the pin BAT; the gate of the MOS transistor MP0 is connected to the output end of the operational amplifier.

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