Voltage control circuit and LED lighting system

Abstract

The present invention discloses a voltage control circuit and an LED lighting system. The voltage control circuit includes a control module and a pressure supply module. The input end of the control module inputs a first voltage, and the output end is connected to the input end of the pressure supply module. The output end of the pressure supply module is connected to the input end of the LED light-emitting module. The LED light-emitting module includes a constant current device. When the first voltage is less than or equal to a preset voltage, the control module is used to provide the first voltage to the LED light-emitting module through the pressure supply module. When the first voltage is greater than the preset voltage, the control module is used to control the pressure supply module to provide a second voltage to the LED light-emitting module, and the second voltage is less than or equal to the preset voltage. In the embodiment of the present invention, when the first voltage fluctuates, it can be ensured that the constant current device in the LED light-emitting module always works at a lower voltage, the temperature will not rise excessively, and the loss generated is relatively low, thereby ensuring that the system has a higher efficiency.

Description

Technical Field

[0001] The present invention relates to the field of voltage control, and in particular to a voltage control circuit and an LED lighting system. Background Art

[0002] At present, semiconductor constant current devices (such as constant current chips or constant current diodes, etc.) can be used in light emitting diode (LED) lighting products to provide constant current to LED light strings. Figure 1 As shown, the constant current device and multiple LEDs can be connected in series in the circuit. Under the action of the input voltage Vin, the constant current device can provide a constant current Iout for the multiple LEDs.

[0003] However, in actual applications, when the input voltage Vin fluctuates and causes the input voltage to increase, when the load voltage Vout of the LED remains unchanged, the voltage difference between the input voltage Vin and the load voltage Vout will be fully applied to the constant current device, resulting in increased losses in the constant current device and relatively low system efficiency. In extreme cases, it may cause device damage or even pose a safety hazard. Summary of the invention

[0004] The embodiments of the present invention provide a voltage control circuit and an LED lighting system to solve the problem that when a semiconductor constant current device is used to provide a constant current for an LED lamp, when the input voltage increases, the loss of the constant current device increases and the system efficiency is low.

[0005] In order to solve the above-mentioned technical problems, the present invention is achieved as follows:

[0006] In a first aspect, a voltage control circuit is provided, which is applied to a light emitting diode (LED) lighting system, and includes a control module and a voltage supply module, wherein:

[0007] The input end of the control module inputs a first voltage, the output end of the control module is connected to the input end of the voltage supply module, the output end of the voltage supply module is connected to the input end of the LED light-emitting module, and the LED light-emitting module includes a constant current device;

[0008] When the first voltage is less than or equal to a preset voltage, the control module is used to provide the first voltage to the LED light-emitting module through the voltage supply module. When the first voltage is greater than the preset voltage, the control module is used to control the voltage supply module to provide a second voltage to the LED light-emitting module, and the second voltage is less than or equal to the preset voltage.

[0009] In a second aspect, an LED lighting system is provided, comprising the above-mentioned voltage control circuit.

[0010] The voltage control circuit provided by the embodiment of the present invention includes a control module and a pressure supply module, the input end of the control module inputs a first voltage, the output end of the control module is connected to the input end of the pressure supply module, the output end of the pressure supply module is connected to the input end of the LED light-emitting module, and the LED light-emitting module includes a constant current device. Based on the voltage control circuit, in the case where the first voltage fluctuates, if the first voltage is less than or equal to the preset voltage, the control module is used to provide the first voltage to the LED light-emitting module through the pressure supply module, and if the first voltage is greater than the preset voltage, the control module is used to control the pressure supply module to provide the second voltage to the LED light-emitting module, and the second voltage is less than or equal to the preset voltage. In this way, in the case where the first voltage fluctuates, it can be ensured that the voltage provided to the LED light-emitting module is always not greater than the preset voltage, thereby ensuring that the constant current device in the LED light-emitting module always works at a lower voltage, the temperature of the constant current device will not rise excessively, and the loss generated is also relatively low, thereby ensuring that the system has a higher efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0012] Figure 1 It is a schematic diagram of a constant current device of an embodiment of the prior art;

[0013] Figure 2 This is a schematic diagram of a circuit structure of an embodiment of the prior art using a constant current device for lighting;

[0014] Figure 3 is a schematic structural diagram of a voltage control circuit according to an embodiment of the present invention;

[0015] Figure 4 is a schematic structural diagram of a voltage divider submodule according to an embodiment of the present invention;

[0016] Figure 5 is a schematic diagram of the structure of a control submodule according to an embodiment of the present invention;

[0017] Figure 6 is a schematic diagram of the structure of a control module according to an embodiment of the present invention;

[0018] Figure 7 is a schematic structural diagram of a pressure supply module according to an embodiment of the present invention;

[0019] Figure 8 It is a schematic diagram of a circuit structure of a lighting circuit using a voltage control circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] 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 described embodiments are 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 creative work are within the scope of protection of the present invention.

[0021] At present, semiconductor constant current devices (hereinafter referred to as constant current devices) can be used in LED lighting products to provide constant current to LED light strings. Figure 1 As shown, Figure 1 It is a schematic diagram of a constant current device according to an embodiment of the prior art.

[0022] Figure 1 In the figure, U0 represents a constant current device, LED1 to LEDn are LED light strings, the constant current device provides a constant current value Iout for the LED light string, Vin is the input voltage, Vout is the load voltage of the LED, V0 is the voltage across the constant current device, and V0 = Vin-Vout. Due to the differences between LED particles, Vout will fluctuate within a small deviation range, and the voltage V0 across the constant current device will also fluctuate, but the output current Iout can be kept constant, which is the working principle of the constant current device.

[0023] based on Figure 1 As shown in the schematic diagram, the overall efficiency of the system can be expressed as: η = Vout / Vin, and the loss of the constant current device can be expressed as: P = (Vin-Vout)*Iout.

[0024] In a typical application scenario, the input voltage Vin can be provided by AC mains, such as Figure 2 shown.

[0025] Figure 2 In the figure, Vin is rectified and filtered by AC 220V 50Hz mains power, and Vin is about DC 286V (about 1.3 times the input AC power). In this case, if the LED load voltage Vout = 266V, and the current Iout provided by the constant current device = 50mA, the system efficiency η = Vout / Vin = 93%, and the loss of the constant current device P = (Vin-Vout)*Iout = 1W. It can be seen that the system efficiency is relatively high at this time, and the loss generated by the constant current device is also relatively low.

[0026] However, in practical applications, the grid voltage of the AC mains will inevitably fluctuate. When the grid voltage increases, for example, AC220V fluctuates to AC260V, the input voltage Vin is about 338V (about 1.3 times the input AC power). If Vout = 266V, Iout = 50mA remains unchanged, the system efficiency η = Vout / Vin = 78.7%, and the constant current device loss P = (Vin-Vout) * Iout = 3.6W. It can be seen that the system efficiency is greatly reduced at this time, and the loss of the constant current device rises rapidly.

[0027] It can be seen that in the scenario where a constant current device is used to provide a constant current for an LED light string, when the input voltage fluctuates and causes the input voltage to increase, while the LED load voltage Vout and the constant current provided by the constant current device remain unchanged, the voltage difference between the input voltage Vin and the load voltage Vout is all applied to the constant current device, resulting in increased losses in the constant current device and relatively low system efficiency. In extreme cases, this may cause device damage or even lead to safety hazards.

[0028] In order to solve the above technical problems, an embodiment of the present invention provides a voltage control circuit, which includes a control module and a voltage supply module, the input end of the control module inputs a first voltage, the output end of the control module is connected to the input end of the voltage supply module, the output end of the voltage supply module is connected to the input end of the LED light-emitting module, and the LED light-emitting module includes a constant current device; when the first voltage is less than or equal to a preset voltage, the control module is used to provide the first voltage to the LED light-emitting module through the voltage supply module, and when the first voltage is greater than the preset voltage, the control module is used to control the voltage supply module to provide a second voltage to the LED light-emitting module, and the second voltage is less than or equal to the preset voltage.

[0029] Based on the voltage control circuit provided in the embodiment of the present invention, when the first voltage fluctuates, it can be ensured that the voltage provided to the LED light-emitting module is always no greater than the preset voltage, thereby ensuring that the constant current device in the LED light-emitting module always operates at a lower voltage, the temperature of the constant current device will not increase excessively, and the loss generated is relatively low, thereby ensuring that the system has a higher efficiency.

[0030] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0031] Figure 3 FIG. 1 is a schematic diagram of a voltage control circuit according to an embodiment of the present invention. Figure 3 As shown, the voltage control circuit may include a control module and a voltage supply module.

[0032] exist Figure 3In the embodiment, the control module includes an input end and an output end, and the pressure supply module includes an input end and an output end, wherein: the input end of the control module inputs a first voltage, the output end of the control module is connected to the input end of the pressure supply module, the output end of the pressure supply module is connected to the input end of the LED light-emitting module, and the LED light-emitting module includes a constant current device.

[0033] In this embodiment, the first voltage is a voltage that can generate fluctuations. When the first voltage is less than or equal to a preset voltage, the control module is used to provide the first voltage to the LED light-emitting module through the voltage supply module, that is, the input voltage of the LED light-emitting module is the first voltage; when the first voltage is greater than the preset voltage, the control module is used to control the voltage supply module to provide the second voltage to the LED light-emitting module, that is, the voltage supply module provides the input voltage to the LED light-emitting module, and the input voltage of the LED light-emitting module is the second voltage, wherein the second voltage is less than or equal to the preset voltage, and the preset voltage can be set according to actual conditions, and is not specifically limited here.

[0034] In this way, based on Figure 3 The voltage control circuit shown can ensure that the voltage provided to the LED light-emitting module is always no greater than the preset voltage when the first voltage fluctuates, thereby ensuring that the constant current device in the LED light-emitting module always operates at a lower voltage, the temperature of the constant current device will not increase excessively, and the loss generated is relatively low, thereby ensuring that the system has a higher efficiency.

[0035] In one implementation, Figure 3 The pressure supply module shown can have a charging and discharging function, wherein, when the first voltage is less than or equal to the preset voltage, the control module is used to control the pressure supply module to charge to the first voltage, and when the first voltage is greater than the preset voltage, the control module is used to control the pressure supply module to provide a second voltage to the LED light-emitting module in the form of discharge. Since the maximum voltage of the pressure supply module during charging is the preset voltage, the second voltage is less than or equal to the preset voltage.

[0036] In this way, when the first voltage fluctuates, the control module controls the charging and discharging of the voltage supply module, so that when the first voltage is less than or equal to or greater than the preset voltage, the first voltage provides voltage to the LED light-emitting module, and controls the voltage supply module to charge to the first voltage. When the first voltage is greater than the preset voltage, the voltage supply module provides an input voltage not greater than the preset voltage to the LED light-emitting module in the form of discharge, thereby ensuring that the constant current device in the LED light-emitting module always operates at a lower voltage, the temperature of the constant current device does not increase excessively, and the loss generated is relatively low, thereby ensuring that the system has a higher efficiency.

[0037] In one implementation, when the pressure supply module has a charging and discharging function, Figure 3 The control module shown can specifically include a voltage divider submodule and a control submodule, wherein the input end of the voltage divider submodule is the input end of the control module, which is used to input the above-mentioned first voltage, the output end of the voltage divider submodule is connected to the input end of the control submodule, and the output end of the control submodule is the output end of the control module, which is connected to the input end of the pressure supply module.

[0038] The voltage divider module can be used to divide the first voltage and output the voltage obtained after the voltage division (hereinafter referred to as the third voltage for the sake of distinction) to the control submodule. Under the action of the third voltage, the control submodule can control the charging and discharging of the voltage supply module.

[0039] Specifically, when the first voltage is less than or equal to the preset voltage, the control submodule can output a fourth voltage under the action of the third voltage, and the fourth voltage is used to control the charging of the pressure supply module. When the first voltage is greater than the preset voltage, the control submodule can output a fifth voltage under the action of the third voltage, and the fifth voltage is used to control the discharging of the pressure supply module.

[0040] In a more specific implementation, the voltage divider module may include a first resistor, a second resistor and a first capacitor. The specific connection structure can be found in Figure 4 .

[0041] Figure 4 In the embodiment, the first end A of the first resistor R1 is the input end of the voltage divider module, which is used to input the first voltage V1, the second end B of the first resistor R1 is connected to the first end C of the second resistor R2 and the first end E of the first capacitor C1 respectively, the second end D of the second resistor R2 is connected to the second end F of the first capacitor C1, and the D end and the F end are grounded, the first end C of the second resistor R2 is the output end of the voltage divider module, and the C end is connected to the input end ( Figure 4 not shown) connection.

[0042] Figure 4 The first capacitor C1 shown can filter the second resistor R2. The first resistor R1 and the second resistor R2 are used to divide the first voltage V1, wherein the voltage across the second resistor R2 is the third voltage mentioned above.

[0043] Optionally, Figure 4 The first resistor R1 shown can be obtained by connecting a plurality of resistors in series or in parallel, and the second resistor R2 can also be obtained by connecting a plurality of resistors in series or in parallel. Figure 4 The following description will be made by taking R1 and R2 as one resistor as an example.

[0044] The control submodule may include a voltage stabilizing device, a third resistor, a fourth resistor and a fifth resistor. The specific connection structure can be found in Figure 5 .

[0045] Figure 5 In the figure, the voltage stabilizing device U1 includes a reference electrode L, a cathode K and an anode M, the reference electrode L is the input end of the control submodule, the anode M is connected to the first end P of the fifth resistor R5, and the M end and the P end are grounded, the cathode K is connected to the first end J of the fourth resistor R4, the second end I of the fourth resistor R4 is respectively connected to the first end H of the third resistor R3 and the second end N of the fifth resistor R5, and the second end N of the fifth resistor R5 is the output end of the control submodule.

[0046] Figure 5 In the control submodule shown, the third voltage is input to the L terminal. When the first voltage is less than or equal to the preset voltage, the third voltage can control the voltage stabilizer U1 to be turned off, and the second terminal N of the fifth resistor R5 outputs the fourth voltage. When the first voltage is greater than the preset voltage, the third voltage can control the voltage stabilizer U1 to be turned on, the fourth resistor R4 and the fifth resistor R5 are connected in parallel, and the second terminal N of the fifth resistor R5 outputs the fifth voltage. When the voltage stabilizer U1 is turned on, since the fourth resistor R4 and the fifth resistor R5 are connected in parallel, the voltage outputted by the second terminal N of the fifth resistor R5 will decrease, that is, the fifth voltage is less than the fourth voltage.

[0047] To understand the working principle of the above voltage divider module and control submodule, please refer to Figure 6 . Figure 6 is a schematic diagram of the structure of a control module according to an embodiment of the present invention, Figure 6 Depend on Figure 4 The voltage divider module and Figure 5 The control submodule shown is composed of:

[0048] Figure 6 In the case where the first voltage V1 is input to the A terminal of the first resistor R1, the first resistor R1 and the second resistor R2 divide the voltage of the first resistor, and the C terminal of the second resistor R2 outputs the third voltage V3 obtained after the voltage division = V1*R2 / (R1+R2). In this embodiment, the sizes of R1 and R2 can be set so that when the first voltage V1 is equal to the preset voltage, the third voltage V11 is exactly equal to the reference voltage of the reference terminal L of the voltage stabilizing device U1.

[0049] In this way, when the first voltage V1 is less than or equal to the preset voltage, the third voltage V11 is less than or equal to the reference voltage of the voltage stabilizer U1. At this time, the voltage stabilizer U1 is cut off. Since the voltage stabilizer U1 is in the cut-off state, the branch of the fourth resistor R4 is disconnected, that is, the fourth resistor R4 is not connected in parallel with the fifth resistor R5. At this time, the N-end of the fifth resistor R5 outputs the fourth voltage V4=V1*R5 / (R3+R5).

[0050] When the first voltage V1 increases due to fluctuation, the third voltage V3 will also increase. At this time, V3 will be greater than the reference voltage of the reference terminal L. In this case, the voltage stabilizer U1 is turned on. Since the voltage stabilizer U1 is in the on state, the fourth resistor R4 is connected in parallel with the fifth resistor R5. At this time, the N-terminal of the fifth resistor R5 outputs the fifth voltage V5=V1*R 45 / (R3+R 45 ), R 45 =R4*R5 / (R4+R5). Since parallel connection will reduce the resistance, and the reduced resistance will reduce the voltage division, the fifth voltage V5 outputted from the N-terminal of the fifth resistor R5 is lower than the fourth voltage V4.

[0051] from Figure 6 It can be seen that when the first voltage V1 fluctuates, the control module can output different voltages to control the voltage supply module to charge or discharge.

[0052] In one implementation, Figure 3 In the case where the pressure supply module shown has the charging and discharging function, the pressure supply module may specifically include a sixth resistor, a field effect transistor, and a second capacitor, the second capacitor being used for charging and discharging. Preferably, in the process of charging the second capacitor, in order to protect the second capacitor, the pressure supply module may also include a seventh resistor. The specific connection structure can be seen in Figure 7 .

[0053] Figure 7 In the figure, the first end a of the sixth resistor R6 is the input end of the voltage supply module, the second end b of the sixth resistor R6 is connected to the gate c of the field effect transistor Q1, the drain e of the field effect transistor Q1 is grounded, the source d of the field effect transistor Q1 is connected to the first end f of the seventh resistor R7, the second end g of the seventh resistor R7 is connected to the first end h of the second capacitor C2, and the first end h and the second end i of the second capacitor C2 are the output ends of the voltage supply module.

[0054] In this embodiment, the voltage input from the control module to the pressure supply module can be set so that when the first voltage is less than or equal to the preset voltage, the field effect transistor Q1 is turned on, and when the first voltage is greater than the preset voltage, the field effect transistor Q1 is turned off.

[0055] When the field effect tube Q1 is turned on, the first voltage can charge the second capacitor C2 through the control module, so that the voltage across the second capacitor C2 reaches the first voltage, and the first voltage is less than or equal to the preset voltage; when the field effect tube Q1 is turned off, the first voltage will not be input to the pressure supply module through the control module. At this time, the second capacitor C2 is discharged. Since the voltage across the second capacitor C2 is less than or equal to the preset voltage, during the discharge of the second capacitor C2, the input voltage provided to the constant current device will not exceed the preset voltage.

[0056] Figure 3 In the voltage control circuit shown, the input end of the control module can be connected to the output end of the voltage rectifier module, and the input end of the voltage rectifier module can input AC mains power. After the AC mains power is input into the voltage rectifier module, the voltage rectifier module can rectify the AC mains power, and a first voltage can be obtained after rectification, and the first voltage can be output to the control module. The first voltage can be a steamed bun wave, that is, a voltage wave obtained by flipping the lower half of the sinusoidal AC power.

[0057] Figure 3 The LED light-emitting module shown may also include at least one LED, which is connected in series with a constant current device, and the sum of the load voltage of the at least one LED (i.e., the voltage across the at least one LED) and the voltage across the constant current device may be equal to the input voltage provided by the voltage supply module to the LED light-emitting module during discharge.

[0058] In one implementation, when the LED light-emitting module includes at least one LED connected in series with the constant current device, the preset voltage can specifically be less than or equal to a sixth voltage, which is less than or equal to the sum of the voltage across the constant current device and the load voltage of at least one LED when the constant current device generates the maximum allowable loss. In this way, it can be ensured that the loss generated by the constant current device is always less than the maximum allowable loss of the constant current device.

[0059] To understand the working principle of the voltage control circuit provided by the embodiment of the present invention, please refer to Figure 8 , Figure 8 It is a structural schematic diagram of a lighting circuit using a voltage control circuit according to an embodiment of the present invention.

[0060] Figure 8 The circuit shown includes AC mains, a voltage rectifier module, a control module, a voltage supply module and an LED light-emitting module, wherein the voltage rectifier module includes a rectifier device M1, the control module includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first capacitor C1 and a voltage stabilizing device U1, the voltage supply module includes a sixth resistor R6, a seventh resistor R7, a field effect transistor Q1 and a second capacitor C2, and the LED light-emitting module includes a constant current device U2 and n LEDs (LED1 to LEDn). Figure 8 The connection relationship between the components in Figures 3 to 7 The above is described in the embodiment shown in the figure and will not be repeated here.

[0061] Figure 8 The lighting circuit shown works as follows:

[0062] The AC mains input voltage rectifier module, the sorting device M1 in the voltage rectifier module can rectify the AC mains, and output a steamed wave after rectification, which can be used as the first voltage V1 to input the control module. In the control module, the first resistor R1 and the second resistor R2 divide the first voltage V1, so that the C end of the second resistor outputs a third voltage V3 = R2*V1 / (R1+R2). Among them, by setting the size of R1 and R2, when the first voltage V1 is equal to the preset voltage, the third voltage V3 is exactly equal to the reference voltage of the voltage stabilizing device U1.

[0063] Since the AC mains power will inevitably fluctuate, the first voltage V1 will also fluctuate. When the first voltage V1 is less than or equal to the preset voltage, since the third voltage V3 is not greater than the reference voltage of the voltage stabilizer U1, the voltage stabilizer U1 is turned off. When the voltage stabilizer U1 is turned off, the fourth resistor R4 in the control module is in a disconnected state, the third resistor R3 and the fifth resistor R5 divide the first voltage V1, and the N-end of the fifth resistor R5 outputs a fourth voltage V4=R5*V1 / (R3+R5). The fourth voltage can control the field effect tube Q1 to be turned on (specifically, the third resistor R3 and the fifth resistor R5 can be set so that the third resistor R3 and the fifth resistor R5 are turned on in the first When the voltage V1 is less than or equal to the preset voltage, the fourth voltage V4 can be greater than the cut-off voltage of the field effect tube Q1, so that the field effect tube Q1 is turned on). When the field effect tube Q1 is turned on, the first voltage V1 can charge the second capacitor C2 through the control module, so that the voltage across the second capacitor C2 is the first voltage V1. At the same time, the first voltage V1 can also provide an input voltage Vin for the LED light-emitting module through the voltage supply module. Vin is equal to the first voltage V1 and is less than the preset voltage. Under the action of the input voltage Vin, the constant current device U2 in the LED light-emitting module provides a constant current for LED1 to LEDn, and LED1 to LEDn emit light.

[0064] When the first voltage V1 is greater than the preset voltage, the third voltage V3 will be greater than the reference voltage of the voltage stabilizer U1. At this time, the voltage stabilizer U1 is turned on. When the voltage stabilizer U1 is turned on, the fourth resistor R4 and the fifth resistor R5 in the control module are connected in parallel. The equivalent resistance R 45 The first voltage V1 is divided by the third resistor R3. 45 The resistance value of the fifth resistor R5 is smaller than that of the fifth resistor R5. Therefore, the N-end of the fifth resistor R5 will output a fifth voltage V5=R 45 *V1 / (R3+R 45), the fifth voltage can control the field effect tube Q1 to be cut off (specifically, the size of the fourth resistor R4 can be set so that when the first voltage V1 is slightly greater than the preset voltage, the fifth voltage V5 is less than or equal to the cut-off voltage of the field effect tube Q1, so that the field effect tube Q1 is cut off). When the field effect tube Q1 is cut off, the second capacitor C2 is disconnected from the control module, and the first voltage V1 will not be able to charge the second capacitor C2 through the control module. At this time, the second capacitor C2 can be discharged to the outside. During the discharge process, the voltage supply module provides the input voltage Vin for the LED light-emitting module. Since the maximum charging voltage at both ends of the second capacitor C2 during the charging process is less than or equal to the preset voltage, the input voltage Vin provided by the voltage supply module to the LED light-emitting module during the discharge process will not exceed the preset voltage. The constant current device U2 provides a constant current to LED1 to LEDn under the action of the input voltage Vin, and LED1 to LEDn emit light.

[0065] It can be seen from this that when the AC mains fluctuates, the input voltage Vin provided to the LED light-emitting module is always no greater than the preset voltage. Therefore, by setting the preset voltage, the constant current device in the LED light-emitting module always operates at a lower voltage, thereby ensuring that the temperature of the constant current device does not rise excessively and the loss generated is relatively low, thereby ensuring that the system has a higher efficiency.

[0066] For example, assuming the preset voltage is 290V, that is, Vin is 290V at maximum, then when the AC mains voltage rises to AC260V, the system efficiency η=Vout / Vin=91.7%, and the constant current device loss P=(Vin-Vout)*Iout=1.2W. Obviously, compared with Figure 2 For the circuit shown, when the grid voltage is AC260V, the system efficiency η=78.7% and the constant current device loss P=3.6W. The embodiment of the present invention can reduce the loss of the constant current device and improve the efficiency of the system.

[0067] The voltage control circuit provided by the embodiment of the present invention includes a control module and a pressure supply module, the input end of the control module inputs a first voltage, the output end of the control module is connected to the input end of the pressure supply module, the output end of the pressure supply module is connected to the input end of the LED light-emitting module, and the LED light-emitting module includes a constant current device. Based on the voltage control circuit, in the case where the first voltage fluctuates, if the first voltage is less than or equal to the preset voltage, the control module is used to provide the first voltage to the LED light-emitting module through the pressure supply module, and if the first voltage is greater than the preset voltage, the control module is used to control the pressure supply module to provide the second voltage to the LED light-emitting module, and the second voltage is less than or equal to the preset voltage. In this way, in the case where the first voltage fluctuates, it can be ensured that the voltage provided to the LED light-emitting module is always not greater than the preset voltage, thereby ensuring that the constant current device in the LED light-emitting module always works at a lower voltage, the temperature of the constant current device will not rise excessively, and the loss generated is also relatively low, thereby ensuring that the system has a higher efficiency.

[0068] An embodiment of the present invention further provides an LED lighting system, which may include the above-mentioned voltage control circuit.

[0069] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0070] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0071] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A voltage control circuit, characterized in that: The voltage control circuit is applied to a light emitting diode (LED) lighting system, and includes a control module and a voltage supply module, wherein: The input end of the control module inputs a first voltage, the output end of the control module is connected to the input end of the voltage supply module, the output end of the voltage supply module is connected to the input end of the LED light-emitting module, and the LED light-emitting module includes a constant current device; When the first voltage is less than or equal to a preset voltage, the control module is used to provide the first voltage to the LED light-emitting module through the voltage supply module, and when the first voltage is greater than the preset voltage, the control module is used to control the voltage supply module to provide a second voltage to the LED light-emitting module, and the second voltage is less than or equal to the preset voltage; The pressure supply module has a charging and discharging function, and the maximum voltage of the pressure supply module during charging is the preset voltage, wherein: When the first voltage is less than or equal to the preset voltage, the control module is used to control the pressure supply module to charge to the first voltage; In the case where the first voltage is greater than the preset voltage, the control module is used to control the voltage supply module to provide the second voltage to the LED light-emitting module in the form of discharge.

2. The voltage control circuit according to claim 1, characterized in that: The control module includes a voltage division submodule and a control submodule, wherein: The first voltage is input to the input end of the voltage dividing submodule, the output end of the voltage dividing submodule is connected to the input end of the control submodule, and the output end of the control submodule is connected to the input end of the pressure supply module; The voltage division submodule is used to divide the first voltage and output a third voltage obtained after the voltage division to the control submodule; When the first voltage is less than or equal to the preset voltage, the control submodule outputs a fourth voltage under the action of the third voltage, and the fourth voltage is used to control the charging of the pressure supply module. When the first voltage is greater than the preset voltage, the control submodule outputs a fifth voltage under the action of the third voltage, and the fifth voltage is used to control the discharging of the pressure supply module.

3. The voltage control circuit according to claim 2, characterized in that: The voltage divider module includes a first resistor, a second resistor and a first capacitor, wherein: The first end of the first resistor is the input end of the voltage divider submodule, the second end of the first resistor is respectively connected to the first end of the second resistor and the first end of the first capacitor, the second end of the second resistor and the second end of the first capacitor are connected and grounded, and the first end of the second resistor is the output end of the voltage divider submodule.

4. The voltage control circuit according to claim 2, characterized in that: The control submodule includes a voltage stabilizing device, a third resistor, a fourth resistor and a fifth resistor, wherein: The voltage stabilizing device includes a reference electrode, a cathode and an anode, the reference electrode is the input end of the control submodule, the anode is connected to the first end of the fifth resistor and is grounded, the cathode is connected to the first end of the fourth resistor, the second end of the fourth resistor is respectively connected to the first end of the third resistor and the second end of the fifth resistor, and the second end of the fifth resistor is the output end of the control submodule; When the first voltage is less than or equal to the preset voltage, the voltage stabilizer is turned off, and the second end of the fifth resistor outputs the fourth voltage. When the first voltage is greater than the preset voltage, the voltage stabilizer is turned on, and the second end of the fifth resistor outputs the fifth voltage. The fourth voltage is greater than the fifth voltage.

5. The voltage control circuit according to claim 1, characterized in that: The voltage supply module includes a sixth resistor, a field effect transistor, and a second capacitor, wherein: The first end of the sixth resistor is the input end of the voltage supply module, the second end of the sixth resistor is connected to the gate of the field effect tube, the drain of the field effect tube is grounded, the source of the field effect tube is connected to the first end of the second capacitor, and the first end and the second end of the second capacitor are the output ends of the voltage supply module; When the first voltage is less than or equal to the preset voltage, the field effect tube is turned on and the second capacitor is charged to the first voltage. When the first voltage is greater than the preset voltage, the field effect tube is turned off and the second capacitor is discharged.

6. The voltage control circuit according to claim 5, characterized in that: The pressure supply module further includes a seventh resistor, wherein: The first end of the seventh resistor is connected to the source of the field effect transistor, and the second end of the seventh resistor is connected to the first end of the second capacitor.

7. The voltage control circuit according to claim 1, characterized in that: The input end of the control module is connected to the output end of the voltage rectifier module, and the input end of the voltage rectifier module inputs AC mains power; The voltage rectification module is used for rectifying the AC mains power to obtain the first voltage, and outputting the first voltage to the control module.

8. The voltage control circuit according to claim 1, characterized in that: The LED light-emitting module further includes at least one LED, and the at least one LED is connected in series with the constant current device; The preset voltage is less than or equal to a sixth voltage, and the sixth voltage is less than or equal to the sum of the voltage across the constant current device and the load voltage of the at least one LED when the constant current device generates a maximum allowable loss.

9. An LED lighting system, characterized in that: The method comprises the voltage control circuit as claimed in any one of claims 1 to 8.

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