Wide voltage input LED driving circuit, method and application thereof

Abstract

The invention discloses a wide voltage input LED drive circuit and method and application thereof, and relates to the technical field of LED drive circuits, the wide voltage input LED drive circuit comprises a rectifier module, a switch switching module, a drive control module and a lamp string, the lamp string is formed by sequentially connecting a first LED, a first diode and a second LED in series, and the rectifier module is used for converting alternating current into direct current and providing a direct current power supply for each module; the switch switching module is used for controlling the on or off state of the lamp string under the control of the driving control module; and the drive control module detects the voltage output by the rectifier module and compares the divided voltage obtained by dividing the voltage by the resistor with the minimum voltage required for segmented conduction of the lamp string to obtain a comparison result, and controls the on / off of the switch switching module and the lamp string according to the comparison result to complete a light emitting period of the LED lamp bead. Through the synergistic effect of the driving control module and the switch switching module, the lamp string can be completely switched on when a wide voltage range is input and is close to the lower limit requirement, and the efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LED driving circuit, in particular to a wide voltage input LED driving circuit, method and application thereof. BACKGROUND

[0002] At present, the traditional lighting drive such as Figure 1 As shown in the drawing, the lamp string LED1, LED2, LED3 is connected in series, under the sine wave input after rectification, in turn LED1 (63V), LED2 (36V), LED3 (36V) lamp bead conduction. Assuming that the lamp voltage is 135V in total of three strings, the voltage required for IC conduction is 15V. Then the input voltage required for complete conduction of the lamp string is VDC>135+15=150V. For example: When the input voltage AC120V, the rectified sine wave voltage is 120*1.414 about 169V, at this time 169>150, the lamp bead is completely turned on; When the input voltage AC130V, the rectified sine wave voltage is 130*1.414 about 184V, at this time 184>150, the lamp bead is completely turned on; When the input voltage AC110V, the rectified sine wave voltage is 110*1.414 about 155V, at this time 155>150, the lamp bead is completely turned on; When the input voltage AC100V, the rectified sine wave voltage is 100*1.414 about 141V, at this time 141<150, the lamp bead is not completely turned on, the third string lamp will be extinguished, only the first string lamp and the second string lamp emit light, because the sum of the lamp voltage of the two strings (100V) is less than 126V, the sum of the lamp voltage of the two strings is calculated according to 141V-15V=126V; When the input voltage AC90V, the rectified sine wave voltage is 90*1.414 about 127V, at this time 127<150, the lamp bead is not completely turned on, the third string lamp will be extinguished, only the first string lamp and the second string lamp emit light, because the sum of the lamp voltage of the two strings (100V) is less than 112V, the sum of the lamp voltage of the two strings is calculated according to 127V-15V=112V.

[0003] It can be seen that under the current driving mode, when the input voltage range is wide and the lower limit is required, the incomplete conduction of the lamp bead seriously affects the lighting effect. SUMMARY

[0004] The purpose of the present application is to provide a wide voltage input LED driving circuit, method and application thereof, which solves the problem that the incomplete conduction of the lamp bead seriously affects the lighting effect when the input voltage range is wide and the lower limit is required.

[0005] The present application is realized by the following technical scheme: In a first aspect, the first embodiment of the present application provides a wide voltage input LED driving circuit, comprising a rectifier module, a switch switching module, a driving control module and a lamp string, the lamp string is connected in series by a first LED lamp bead, a first diode and a second LED lamp bead, the output end of the rectifier module is connected with the switch switching module, the driving control module, the anode of the first LED lamp bead and the anode of the second LED lamp bead respectively, the switch switching module is connected with the driving control module, the anode of the first LED lamp bead and the anode of the second LED lamp bead respectively, and the driving control module is connected with the cathode of the first LED lamp bead and the cathode of the second LED lamp bead respectively. The rectifier module is used for converting alternating current into direct current to provide direct current power supply for each module. The switch switching module is used for controlling the on or off state of the lamp string under the control of the driving control module. The driving control module compares the voltage divided voltage obtained by dividing the voltage output by the rectifier module by a resistor with the minimum voltage required for the lamp string to be segmented to be turned on, obtains a comparison result, and controls the on or off of the switch switching module and the lamp string according to the comparison result to complete a light-emitting period of the LED lamp bead.

[0006] Further, the segmented conduction includes first segment conduction, second segment conduction and third segment conduction, the minimum voltage corresponding to the first segment conduction is the minimum voltage required for the second LED lamp bead to be turned on, the minimum voltage corresponding to the second segment conduction is the minimum voltage required for the first LED lamp bead to be turned on, and the minimum voltage corresponding to the third segment conduction is the sum of the minimum voltages required for the first LED lamp bead and the second LED lamp bead to be turned on.

[0007] Further, the driving control module comprises a first PT1917 chip, a first capacitor, a first resistor, a second resistor and a fourth resistor, the first pin of the PT1917 chip is connected with one end of the first resistor and the second resistor respectively, the other end of the second resistor is grounded, the other end of the first resistor is connected with the sixteenth pin of the PT1917 chip, the rectifier module and the switch switching module respectively, the eighth pin of the PT1917 chip is connected with the cathode of the second LED lamp bead, the anode of the second LED lamp bead is connected with the switch switching module, the ninth pin of the PT1917 chip is connected with the cathode of the first LED lamp bead and the anode of the first diode respectively, the anode of the first LED lamp bead is connected with the rectifier module and the switch switching module respectively, the thirteenth pin and the fourteenth pin of the PT1917 chip are connected with one end of the first capacitor, the other end of the first capacitor is connected with one end of the fourth resistor and then grounded, and the other end of the fourth resistor is connected with the tenth pin of the PT1917 chip.

[0008] Further, the switch switching module comprises a PT1913 chip, a voltage stabilizing tube and a third resistor, the voltage stabilizing tube is connected between the first pin and the second pin of the PT1913 chip, and then connected with the anode of the second LED lamp bead and the cathode of the first diode respectively, the second pin of the PT1913 chip is connected with one end of the third resistor and the fifth pin of a PT1917 chip respectively, the other end of the third resistor is connected with the output end of the rectifying module, the other end of the first resistor and the sixteenth pin of the PT1917 chip respectively, and the seventh pin and the eighth pin of the PT1913 chip are connected with the anode of the first LED lamp bead respectively.

[0009] Further, the drive control module further comprises a second PT1917 chip, which is connected with the first PT1917 chip in parallel and then connected with the lamp string.

[0010] Further, the rectifying module adopts a half-wave, full-wave or bridge rectifying circuit.

[0011] In the second aspect, another embodiment of the present application provides a wide-voltage-input LED driving method, which is suitable for the wide-voltage-input LED driving circuit described in the above embodiment, and comprises the following steps: The rectifying module converts the input alternating voltage into direct current voltage, and provides direct current power supply for each module in the circuit; The drive control module detects the divided voltage obtained by dividing the voltage output by the rectifying module through the resistor, compares the divided voltage with the minimum voltage required for the segmented conduction of the lamp string, obtains a comparison result, controls the opening or closing of the switch switching module and the lamp string according to the comparison result, and completes one light-emitting period of the LED lamp bead. The switch switching module controls the opening or closing state of the lamp string under the control of the drive control module.

[0012] Further, the segmented conduction comprises first segment conduction, second segment conduction and third segment conduction, the minimum voltage corresponding to the first segment conduction is the minimum voltage required for the conduction of the second LED lamp bead, the minimum voltage corresponding to the second segment conduction is the minimum voltage required for the conduction of the first LED lamp bead, and the minimum voltage corresponding to the third segment conduction is the sum of the minimum voltages required for the conduction of the first LED lamp bead and the second LED lamp bead.

[0013] Further, the specific method of comparing the divided voltage with the minimum voltage required for the segmented conduction of the lamp string, obtaining a comparison result, and controlling the opening or closing of the switch switching module and the lamp string according to the comparison result to complete one light-emitting period of the LED lamp bead comprises the following steps: When the divided voltage rises from 0 to the minimum voltage corresponding to the first segment conduction, the drive control module controls the DR1 channel to be closed, and the drive control module controls the second LED lamp bead to be conducted. When the voltage is rising from the minimum voltage corresponding to the first segment to the minimum voltage corresponding to the second segment, the current of the DR1 channel starts to decrease, and the current of the DR2 channel starts to increase, when the current of the DR1 channel decreases to 0, the driving control module controls the DR1 channel to be turned off, and the driving control module controls the first LED lamp bead to be turned on. When the voltage is rising from the minimum voltage corresponding to the second segment to the minimum voltage corresponding to the third segment, the current of the DR2 channel starts to decrease, and the current of the DR1 channel starts to increase, when the current of the DR2 channel decreases to 0, the driving control module controls the DR2 channel to be turned off, and the driving control module controls the first LED lamp bead and the second LED lamp bead to be turned on.

[0014] In a third aspect, an application of the LED driving circuit with wide voltage input provided by another embodiment of the present application includes the LED driving circuit with wide voltage input described in the above embodiments.

[0015] Compared with the prior art, the present application has the following advantages and beneficial effects: The LED driving circuit with wide voltage input, the method and the application thereof provided by the embodiments of the present application can realize that the lamp string can be completely turned on and the efficiency is improved when a relatively wide voltage range and a lower limit requirement are inputted through the synergistic effect of the driving control module and the switching module.

[0016] The effect of simulating three-stage current work is realized through the driving control of the two lamp strings, and the product cost is greatly saved. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the example embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings: Figure 1 It is a traditional lighting driving circuit diagram; Figure 2 It is a principle block diagram of the LED driving circuit with wide voltage input provided by the first embodiment of the present application; Figure 3 It is a circuit diagram of the LED driving circuit with wide voltage input provided by the first embodiment of the present application; Figure 4 It is a lamp string conduction three-stage current waveform diagram of the LED driving circuit with wide voltage input provided by the first embodiment of the present application; Figure 5 It is a specific control logic diagram of the driving control module; Figure 6 The waveform output by the drive control module; Figure 7 This is a circuit diagram showing the application of the wide voltage input LED driving circuit proposed in the first embodiment of the present invention in the flicker-free mode. Figure 8 A flowchart of a wide voltage input LED driving method provided in another embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0019] like Figure 2 As shown in Figure 3, the first embodiment of the present invention provides a wide voltage input LED driving circuit, including: a rectifier module, a switch module, a drive control module, and a light string. The light string consists of a first LED LED1, a first diode D1, and a second LED LED2 connected in series. The output terminal of the rectifier module is connected to the switch module, the drive control module, the anode of the first LED LED1, and the anode of the second LED LED2, respectively. The switch module is connected to the drive control module, the anode of the first LED LED1, and the anode of the second LED LED2, respectively. The drive control module is connected to the cathode of the first LED LED1 and the cathode of the second LED LED2, respectively. The rectifier module is used to convert AC power into DC power to provide DC power to each module. The switch switching module is used to control the on or off state of the light string under the control of the drive control module. The drive control module detects the voltage output by the rectifier module and compares the divided voltage obtained by resistor voltage division with the minimum voltage required for the LED string to conduct in segments. Based on the comparison result, it controls the switch switching module and the LED string to turn on or off to complete one light-emitting cycle of the LED beads.

[0020] The segmented conduction includes a first segment conduction, a second segment conduction, and a third segment conduction. The minimum voltage corresponding to the first segment conduction is the minimum voltage required for the second LED bead LDE2 to conduct. The minimum voltage corresponding to the second segment conduction is the minimum voltage required for the first LED bead LED1 to conduct. The minimum voltage corresponding to the third segment conduction is the sum of the minimum voltages required for both the first LED bead LED1 and the second LED bead LED2 to conduct.

[0021] The drive control module includes a first PT1917 chip, a first capacitor C1, a first resistor R1, a second resistor C2, and a fourth resistor R4. The first pin of the PT1917 chip is connected to one end of the first resistor R1 and the second resistor R2, respectively. The other end of the second resistor R2 is grounded. The other end of the first resistor R1 is connected to the sixteenth pin of the PT1917 chip, the rectifier module, and the switch module. The eighth pin of the PT1917 chip is connected to the cathode of the second LED bead LED2. The anode of the second LED bead LED2 is connected to the switch module. The ninth pin of the PT1917 chip is connected to the cathode of the first LED bead LED1 and the anode of the first diode D1, respectively. The anode of the first LED bead LED1 is connected to the rectifier module and the switch module. The thirteenth and fourteenth pins of the PT1917 chip are connected to one end of the first capacitor C1. The other end of the first capacitor C1 is connected to one end of the fourth resistor R4 and then grounded. The other end of the fourth resistor R4 is connected to the tenth pin of the PT1917 chip.

[0022] The switching module includes a PT1913 chip, a Zener diode ZD, and a third resistor R3. The first and second pins of the PT1913 chip are connected to the Zener diode and then to the anode of the second LED LED2 and the cathode of the first diode D1, respectively. The second pin of the PT1913 chip is connected to one end of the third resistor R3 and the fifth pin of the PT1917 chip. The other end of the third resistor R3 is connected to the output terminal of the rectifier module, the other end of the first resistor R1, and the sixteenth pin of the PT1917 chip. The seventh and eighth pins of the PT1913 chip are connected to the anode of the first LED LED1, respectively.

[0023] For example, if the VIN voltage of the PT1917 chip is 120V, then the current flow in the first stage is: resistor voltage divider DC_BUS → PT1913 → LED2 (54V) → DR1 channel; the current flow in the second stage is: resistor voltage divider DC_BUS → PT1913 → LED1 (99V) → DR2 channel; resistor voltage divider DC_BUS → PT1913 → LED1 (99V) → LED2 (54V) → DR1 channel, totaling 153V for the LEDs. The minimum AC voltage corresponding to the first stage of conduction is (54+15) / 1.414 = 48V; the minimum AC voltage corresponding to the second stage of conduction is (99+15) / 1.414 = 81V; the minimum AC voltage corresponding to the third stage of conduction is (153+15) / 1.414 = 119V. Theoretically, an input voltage of 50V is sufficient to produce light. When the voltage reaches 81V or higher, both strings of lights will be fully illuminated. Furthermore, when the voltage reaches 120V, the light strings will conduct, resulting in three current waveforms as shown in the diagram.Figure 4 as shown

[0024] The MULT (pin 1) of the PT1917 chip detects the input voltage divided by the first resistor R1 and the second resistor R2, compares the divided voltage DC_BUS with the minimum voltage of segmented conduction to obtain a comparison result, and the SPC (pin 5) of the PT1917 chip controls the on-off of PT1913 and the on-off timing of the three channels of the DR1 channel and the DR2 channel to complete one light-emitting cycle of the LED.

[0025] As Figure 5 shown, the specific control logic diagram of the drive control module is shown, and its output waveform diagram is as Figure 6 shown. The specific control method is as follows: 1. When the DC_BUS voltage rises from 0 to 54V, at this time the comparator outputs ctrl = 1 as a high level, and the inverter outputs xctrl = 0 as a low level, that is, M0 conducts, and at this time the DR2 channel conducts. The voltages at both ends of the positive and negative of the operational amplifier OP2 are equal, that is, VREF2 = VCS = ref1; the voltage at the positive end of the operational amplifier OP1, ref2 > VCS = ref1, that is, the operational amplifier OP1 outputs a high level, and the DR1 channel is opened to control the conduction of the second LED2.

[0026] 2. When the DC_BUS voltage rises from 54V to 99V, the current of the DR2 channel starts to decrease slowly, and the current of the DR1 channel starts to increase slowly. After the current of the DR2 channel decreases to 0, it can be seen from the equal voltages at both ends of the positive and negative of the operational amplifier OP1 that VREF1 = VCS = ref2; from the operational amplifier OP2, VREF2 = ref1 < VCS = ref2, that is, the output of the operational amplifier OP2 is 0, and the DR2 channel is closed.

[0027] 3. When the DC_BUS voltage rises from 99V to the voltage at which the ctrl signal output by the comparator flips, at this time the comparator outputs ctrl = 0 as a low level, and the inverter xctrl = 1 as a high level; that is, M0 is turned off, and VREF2 is switched to ref3. At this time, the voltage at the positive end of the operational amplifier OP2, ref3 > VCS = ref2, that is, the output of the operational amplifier OP2 is a high level, and the DR2 channel is opened.

[0028] 4. When the DC_BUS voltage continues to rise to 153V, the ctrl voltage signal output by the comparator flips, the current of the DR1 channel starts to decrease, and the current of the DR2 channel starts to increase. When the current of the DR1 channel decreases to 0, it can be seen from the operational amplifier OP2 that VREF2 = VCS = ref3, and the voltage at the positive end of the operational amplifier OP1, VREF1 = ref2 < VCS = ref3, that is, the output of the operational amplifier OP1 is a low level 0, that is, the DR1 channel is closed.

[0029] 5. Keep the DR2 channel open as the DC_BUS voltage continues to rise from 153V to its maximum value.

[0030] 6. When the DC_BUS voltage drops from its maximum value to 153V, the DR2 channel current begins to decrease, and the DR1 current begins to increase. When the DR2 channel current drops to 0, the voltages at the positive and negative terminals of op-amp OP1 are equal, VCS=VREF1=ref2, while VREF2=ref3 at the positive terminal of op-amp OP2. Therefore, op-amp OP2 outputs a high level, and the DR2 channel is turned on.

[0031] 7. When the DC_BUS voltage drops from 153V to the voltage value toggled by the comparator output signal ctrl, the comparator output signal ctrl=1 is high and the inverter xctrl=0 is low; that is, M0 is turned on, and at the same time VREF2 switches to ref1. At this time, the voltage VCS at the negative terminal of op-amp OP2 is less than ref1, so the output of OP2 is 0 and the DR2 channel is turned off.

[0032] 8. When the DC_BUS voltage drops to 99V, the comparator output signal ctrl flips. Due to insufficient voltage, the DR1 channel current begins to decrease, while the DR2 current begins to increase. When the DR1 channel current decreases to 0, VCS=VREF2=ref1, and VREF1=ref2>VCS=ref1, that is, the op-amp OP1 outputs a high level, and the DR1 channel is turned on.

[0033] 9. When the DC_BUS voltage drops from 99V to 54V, keep op-amp OP2 working, VCS=VREF2=ref1, and keep channel DR1 open.

[0034] 10. When the DC_BUS voltage drops below 54V, the DR2 channel current gradually decreases to 0.

[0035] In summary, through the coordinated action of the drive control module and the switch switching module, the LED string can be fully turned on when the input voltage range is relatively wide and the lower limit requirement is met, thereby improving efficiency.

[0036] The drive control module also includes a second PT1917 chip, which is connected in parallel with the first PT1917 chip and then connected to the LED string. Connecting multiple PT1917 chips in parallel for high-power applications significantly reduces the cost of flicker reduction.

[0037] Existing LED driver circuits require three LED strings and three flicker-eliminating chips to achieve flicker-free operation. For example... Figure 7The diagram illustrates the application circuit of the wide-voltage input LED driver circuit proposed in this embodiment of the invention in flicker-free mode. Pins 5, 6, 7, and 8 of U2 (PT1913) work with the main control chip U1 to achieve multi-segment operation. Pins 1, 2, 7, and 8, together with Zener diode ZD1, diode D1, polarized capacitor EC1, and capacitor C2, form the flicker-free circuit for the first segment of lamps, without adding an additional power MOS or driver IC for flicker removal. The flicker-free IC for the second string of lamps is provided by U3 (PT1908), capacitor C3, and polarized capacitor EC2. In this operation, it can be seen that the wide-voltage input LED driver circuit of this application saves many chips compared to traditional applications in flicker-free mode, thereby reducing the overall product cost.

[0038] The wide voltage input LED driver circuit provided in the embodiment of the present invention was simulated using simulation software. The simulation results can verify the effectiveness of the embodiment of the present invention: there are two current waveforms operating when the input is 80V, two current waveforms operating when the input is 100V, three current waveforms operating when the input is 120V, and three current waveforms operating when the input is 130V.

[0039] like Figure 8 As shown, another embodiment of the present invention provides a wide voltage input LED driving method, applicable to the wide voltage input LED driving circuit described in the first embodiment above, comprising: The rectifier module converts the input AC voltage into DC voltage, providing DC power to the various modules in the circuit; The drive control module detects the voltage divided by the resistors of the voltage output from the rectifier module, compares the divided voltage with the minimum voltage required for the LED string to conduct in segments, obtains the comparison result, and controls the switch switching module and the LED string to turn on or off to complete one light-emitting cycle of the LED beads. The switch switching module controls the on or off state of the light string under the control of the drive control module.

[0040] The segmented conduction includes a first segment conduction, a second segment conduction, and a third segment conduction. The minimum voltage corresponding to the first segment conduction is the minimum voltage required for the second LED to conduct. The minimum voltage corresponding to the second segment conduction is the minimum voltage required for the first LED to conduct. The minimum voltage corresponding to the third segment conduction is the sum of the minimum voltages required for both the first and second LEDs to conduct.

[0041] The specific method for comparing the voltage divider with the minimum voltage required for segmented conduction of the LED string to obtain the comparison result, and controlling the switching module and the LED string to turn on or off based on the comparison result to complete one light-emitting cycle of the LED beads includes: When the voltage divider rises from 0 to the minimum voltage corresponding to the first stage of conduction, the drive control module controls the DR1 channel to close, and the drive control module controls the second LED to conduct. When the voltage divider rises from the minimum voltage corresponding to the first stage of conduction to the minimum voltage corresponding to the second stage of conduction, the current of DR1 channel begins to decrease, and the current of DR2 channel begins to increase. When the current of DR1 channel decreases to 0, the drive control module controls DR1 channel to disconnect and the drive control module controls the first LED to conduct. When the voltage divider rises from the minimum voltage corresponding to the second stage of conduction to the minimum voltage corresponding to the third stage of conduction, the current of the DR2 channel begins to decrease, and the current of the DR1 channel begins to increase. When the current of the DR2 channel decreases to 0, the drive control module controls the DR2 channel to disconnect, and the drive control module controls the first LED bead to conduct and the second LED bead to conduct.

[0042] Another embodiment of the present invention provides an application of a wide voltage input LED driving circuit, including the wide voltage input LED driving circuit described in the first embodiment above.

[0043] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wide voltage input LED driver circuit, characterized in that, include: The system comprises a rectifier module, a switch module, a drive control module, and a light string. The light string consists of a first LED, a first diode, and a second LED connected in series. The output terminal of the rectifier module is connected to the switch module, the drive control module, the anode of the first LED, and the anode of the second LED. The switch module is connected to the drive control module, the anode of the first LED, and the anode of the second LED. The drive control module is connected to the cathode of the first LED and the cathode of the second LED. The rectifier module is used to convert AC power into DC power to provide DC power to each module. The switch switching module is used to control the on or off state of the light string under the control of the drive control module. The drive control module detects the voltage output by the rectifier module and compares the divided voltage obtained by resistor voltage division with the minimum voltage required for the LED string to conduct in segments. Based on the comparison result, it controls the switch switching module and the LED string to turn on or off to complete one light-emitting cycle of the LED beads.

2. The wide voltage input LED driving circuit according to claim 1, characterized in that, The segmented conduction includes a first segment conduction, a second segment conduction, and a third segment conduction. The minimum voltage corresponding to the first segment conduction is the minimum voltage required for the second LED to conduct. The minimum voltage corresponding to the second segment conduction is the minimum voltage required for the first LED to conduct. The minimum voltage corresponding to the third segment conduction is the sum of the minimum voltages required for both the first and second LEDs to conduct.

3. The wide voltage input LED driving circuit according to claim 1 or 2, characterized in that, The drive control module includes a first PT1917 chip, a first capacitor, a first resistor, a second resistor, and a fourth resistor. The first pin of the PT1917 chip is connected to one end of the first and second resistors, respectively. The other end of the second resistor is grounded. The other end of the first resistor is connected to the sixteenth pin of the PT1917 chip, a rectifier module, and a switching module, respectively. The eighth pin of the PT1917 chip is connected to the cathode of the second LED, and the anode of the second LED is connected to the switching module. The ninth pin of the PT1917 chip is connected to the cathode of the first LED and the anode of the first diode, respectively. The anode of the first LED is connected to the rectifier module and the switching module, respectively. The thirteenth and fourteenth pins of the PT1917 chip are connected to one end of the first capacitor. The other end of the first capacitor is connected to one end of the fourth resistor and then grounded. The other end of the fourth resistor is connected to the tenth pin of the PT1917 chip.

4. The wide voltage input LED driving circuit according to claim 3, characterized in that, The switching module includes a PT1913 chip, a Zener diode, and a third resistor. The first and second pins of the PT1913 chip are connected to the Zener diode and then to the anode of the second LED and the cathode of the first diode, respectively. The second pin of the PT1913 chip is connected to one end of the third resistor and the fifth pin of the PT1917 chip. The other end of the third resistor is connected to the output terminal of the rectifier module, the other end of the first resistor, and the sixteenth pin of the PT1917 chip. The seventh and eighth pins of the PT1913 chip are connected to the anode of the first LED, respectively.

5. The wide voltage input LED driving circuit according to claim 4, characterized in that, The drive control module also includes a second PT1917 chip, which is connected in parallel with the first PT1917 chip and then connected to the light string.

6. The wide voltage input LED driving circuit according to claim 1, characterized in that, The rectifier module uses a half-wave, full-wave, or bridge rectifier circuit.

7. A wide-voltage input LED driving method, applicable to the wide-voltage input LED driving circuit as described in any one of claims 1-6, characterized in that, include: The rectifier module converts the input AC voltage into DC voltage, providing DC power to the various modules in the circuit; The drive control module detects the voltage divided by the resistors of the voltage output from the rectifier module, compares the divided voltage with the minimum voltage required for the LED string to conduct in segments, obtains the comparison result, and controls the switch switching module and the LED string to turn on or off to complete one light-emitting cycle of the LED beads. The switch switching module controls the on or off state of the light string under the control of the drive control module.

8. The LED driving method with wide voltage input according to claim 7, characterized in that, The segmented conduction includes a first segment conduction, a second segment conduction, and a third segment conduction. The minimum voltage corresponding to the first segment conduction is the minimum voltage required for the second LED to conduct. The minimum voltage corresponding to the second segment conduction is the minimum voltage required for the first LED to conduct. The minimum voltage corresponding to the third segment conduction is the sum of the minimum voltages required for both the first and second LEDs to conduct.

9. The LED driving method with wide voltage input according to claim 8, characterized in that, The specific method for comparing the voltage divider with the minimum voltage required for segmented conduction of the LED string, obtaining the comparison result, and controlling the switching module and the LED string to turn on or off based on the comparison result to complete one light-emitting cycle of the LED beads includes: When the voltage divider rises from 0 to the minimum voltage corresponding to the first stage of conduction, the drive control module controls the DR1 channel to close, and the drive control module controls the second LED to conduct. When the voltage divider rises from the minimum voltage corresponding to the first stage of conduction to the minimum voltage corresponding to the second stage of conduction, the current of DR1 channel begins to decrease, and the current of DR2 channel begins to increase. When the current of DR1 channel decreases to 0, the drive control module controls DR1 channel to disconnect and the drive control module controls the first LED to conduct. When the voltage divider rises from the minimum voltage corresponding to the second stage of conduction to the minimum voltage corresponding to the third stage of conduction, the current of the DR2 channel begins to decrease, and the current of the DR1 channel begins to increase. When the current of the DR2 channel decreases to 0, the drive control module controls the DR2 channel to disconnect, and the drive control module controls the first LED bead to conduct and the second LED bead to conduct.

10. An application of a wide voltage input LED driver circuit, characterized in that, Includes an LED driver circuit with a wide voltage input as described in any one of claims 1-6.

Images