Flickback elimination circuit, lamp and lighting system

Abstract

The utility model relates to the technical field of illumination, and discloses a backflash elimination circuit, a lamp and an illumination system. According to the backflash elimination circuit provided by the utility model, the anti-backflash circuit is arranged, the first power supply end of the anti-backflash circuit is connected with the first power supply end or the second power supply end to take electricity, and the first control end is connected with the first capacitor or is connected between the output end of the constant voltage chip and the second signal end; the anti-backflash circuit consumes the electric quantity of the first capacitor or pulls down the signal of the second signal end, so that the post-stage driving circuit is controlled to output the driving signal to eliminate the backflash phenomenon, discomfort caused by the backflash phenomenon of the lamp to a user is effectively avoided, and meanwhile, the user experience is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of lighting, and specifically relates to a flashback elimination circuit, a lamp and a lighting system. Background Art

[0002] Most of the dimming drivers on the market now adopt a two-stage scheme, such as constant voltage in the front stage and constant current in the rear stage. The dimming signal terminal and the LED dimming driver output terminal adopt an optocoupler plus transformer isolation scheme. The PWM signal of this driving scheme is directly coupled to the PWM input terminal of the rear-stage dimming driver after being isolated by the optocoupler from the module end, so that its output current is controlled by the PWM signal. This scheme is prone to flashback phenomenon during use. Specifically, the flashback phenomenon means that when the dimming driver is in a low-brightness state and the AC220V power supply is cut off at this time, the brightness of the lamp will suddenly become bright and flash once before entering the shutdown state. The flashback phenomenon not only affects the normal use of users, but also easily causes discomfort to users, and even causes eye damage to users. Content of the Utility Model

[0003] To solve the deficiencies of the existing technology described above, the utility model provides a flashback elimination circuit, a lamp and a lighting system. The flashback elimination circuit obtains power by connecting the first power supply terminal of the anti-flashback circuit to the first power supply terminal or the second power supply terminal. The first control terminal is connected to the first capacitor or connected between the output terminal of the constant voltage chip and the second signal terminal to control the output of the driving signal by the rear-stage driving circuit, thereby avoiding the flashback phenomenon.

[0004] The technical effects to be achieved by the utility model are realized through the following aspects:

[0005] In the first aspect, the utility model provides a flashback elimination circuit, including:

[0006] A front-stage constant voltage circuit is provided with a first input terminal, a first power supply terminal and a second power supply terminal. The first input terminal is connected to the input mains electricity, and the first power supply terminal is connected to the positive pole of the LED light source through a first diode;

[0007] A dimming circuit is connected to the second power supply terminal to obtain power, and is used for receiving a dimming signal and converting the dimming signal into a PWM signal. The PWM signal is output through the first signal terminal of the dimming circuit;

[0008] A rear-stage driving circuit includes a constant voltage chip, a rear-stage driving chip and a first capacitor. The power input terminals of the constant voltage chip, the rear-stage driving chip and the first capacitor are all connected to the output terminal of the first diode to obtain power. The rear-stage driving chip is provided with a second signal terminal and a driving output terminal. The second signal terminal is connected to the first signal terminal and the output terminal of the constant voltage chip, and the driving output terminal is connected to the negative pole of the LED light source;

[0009] And an anti-backflash circuit, which is provided with a first power supply terminal and a first control terminal. The first power supply terminal is connected to the first power supply terminal or the second power supply terminal to obtain power, and the first control terminal is connected to the first capacitor or connected between the output terminal of the constant voltage chip and the second signal terminal to control the driving circuit at the rear stage to output a driving signal.

[0010] In some implementation manners, the anti-backflash circuit includes a third diode, a third capacitor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a triode.

[0011] The input end of the third diode is the first power supply terminal, and the input end of the third diode is connected to the first power supply terminal. The output end of the third diode is connected to the third capacitor, the base of the triode, the fourth resistor and the sixth resistor through the seventh resistor.

[0012] The emitter of the triode is connected to the fifth resistor, and the collector is grounded; the other end of the fifth resistor is the first control terminal and the other end of the fifth resistor is connected to the first capacitor.

[0013] The other ends of the fourth resistor and the third capacitor are both grounded, and the other end of the sixth resistor is connected to the output end of the first diode.

[0014] In some implementation manners, the anti-backflash circuit includes a third diode, a fourth resistor and a second optocoupler.

[0015] The input end of the third diode is the first power supply terminal, and the input end of the third diode is connected to the second power supply terminal. The output end of the third diode is connected to the first end of the second optocoupler through the fourth resistor.

[0016] The fourth end and the third end of the second optocoupler are the first control terminal, and the fourth end is connected to the output terminal of the constant voltage chip, the third end is connected to the second signal terminal, and the second end is grounded.

[0017] In some implementation manners, the front-stage constant voltage circuit includes an AC-DC chip and a transformer.

[0018] The input end of the AC-DC chip is the first input end and the output end of the AC-DC chip is connected to the transformer.

[0019] The first power supply terminal and the second power supply terminal are arranged on the transformer to output a power supply.

[0020] In some implementation manners, the dimming circuit includes a dimming chip, a first optocoupler, a first resistor and a second diode.

[0021] The input end of the second diode is connected to the second power supply terminal.

[0022] The dimming chip is provided with a signal input end, a signal output end and a second power supply end. The second power supply end is connected to the output end of the second diode. The signal input end is connected to an external adjustment device. The signal output end is connected to the second end of the first optocoupler.

[0023] The first end of the first optocoupler is connected to the output end of the second diode through a first resistor. The fourth end is the first signal end for outputting a PWM signal to the subsequent driving circuit, and the third end is grounded.

[0024] In some implementation manners, the output end of the second diode is further connected to a second capacitor, and the other end of the second capacitor is grounded.

[0025] In some implementation manners, the signal input end of the dimming chip is used to receive a 0 - 10V dimming signal.

[0026] In some implementation manners, the subsequent driving circuit is further provided with a second resistor and a third resistor. The other end of the second resistor is grounded. The third resistor is connected between the output end of the constant - voltage chip and the second signal end, or the third resistor is connected between the output end of the constant - voltage chip and the first control end.

[0027] In a second aspect, the present invention provides a lamp, including an integrated circuit board and an LED light source. The integrated circuit board integrates the above - mentioned flashback elimination circuit, and the integrated circuit board is electrically connected to the LED light source through the flashback elimination circuit.

[0028] In this implementation manner, the flashback elimination circuit is integrated in the integrated circuit board of the lamp. The integrated circuit board can be located in the driving part of the lamp or the circuit board part of the whole lamp. The LED light source is turned on and off through the flashback elimination circuit. When the LED light source is turned on, the dimming circuit controls the brightness adjustment of the lamp by receiving a 0 - 10V dimming signal. And when the LED light source is turned off, the anti - flashback circuit consumes the power of the first capacitor or pulls down the signal of the second signal end, thereby controlling the subsequent driving circuit to output a driving signal to eliminate the flashback phenomenon.

[0029] In a third aspect, the present invention provides an illumination system, including a control terminal and the above - mentioned lamp;

[0030] The control terminal is electrically connected to the driving power supply of the lamp, and / or

[0031] The control terminal performs information interaction with the driving power supply.

[0032] In this implementation mode, the lighting system can be applied to intelligent lighting in various usage patterns and application scenarios. Through the interaction between the control terminal and the lamps, the intelligent adjustment of the lighting devices can be realized, the intelligent lighting function with multiple scenarios and multiple uses is achieved, and the occurrence of backflash is prevented after the lamps are turned off, improving the user experience.

[0033] In summary, the present utility model has at least the following beneficial effects:

[0034] The backflash elimination circuit provided by the present utility model controls the output drive signal of the subsequent drive circuit to eliminate the backflash phenomenon by setting an anti-backflash circuit. The first power supply terminal of the anti-backflash circuit is connected to the first power supply terminal or the second power supply terminal to obtain power, and the first control terminal is connected to the first capacitor or connected between the output terminal of the constant voltage chip and the second signal terminal. The anti-backflash circuit consumes the power of the first capacitor or pulls down the signal of the second signal terminal. This effectively avoids the discomfort caused to users by the backflash phenomenon of the lamps and improves the user experience at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic structural diagram of the backflash elimination circuit of Embodiment 1 of the present utility model.

[0036] Figure 2 It is the first circuit schematic diagram of the backflash elimination circuit of Embodiment 2 of the present utility model.

[0037] Figure 3 It is the second circuit schematic diagram of the backflash elimination circuit of Embodiment 3 of the present utility model.

[0038] Reference numerals in the drawings:

[0039] 110, front-stage constant voltage circuit; 120, dimming circuit; 130, subsequent drive circuit; 140, anti-backflash circuit; 150, LED light source;

[0040] AC-DC, AC-DC chip; T1, transformer; D1, first diode; D2, second diode; D3, third diode; U1, dimming chip; U2, first optocoupler; U3, subsequent drive chip; U4, constant voltage chip; U5, second optocoupler; EC1, first capacitor; EC2, second capacitor; C3, third capacitor; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; Q1, triode. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. The described embodiments are some, but not all, of the embodiments of the present utility model.

[0042] Therefore, the following detailed description of the embodiments of the present utility model provided in the drawings is not intended to limit the scope of the claimed present utility model, but merely represents selected embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts fall within the scope of protection of the present utility model.

[0043] Example 1:

[0044] Please refer to the attached Figure 1 , this embodiment provides a flashback elimination circuit, including a pre-stage constant voltage circuit 110, a dimming circuit 120, a post-stage drive circuit 130, and an anti-flashback circuit 140 to avoid the occurrence of flashback phenomenon. Specifically, the pre-stage constant voltage circuit 110 is provided with a first input terminal, a first power supply terminal T1_13, and a second power supply terminal T1_9. The first input terminal is connected to the input mains power. The first power supply terminal T1_13 is connected to the positive electrode of the LED light source 150 through a first diode D1; the pre-stage constant voltage circuit 110 is used to convert the input mains power into the power supply for each circuit of the embodiments of the present utility model. The input mains power can be a 220V AC circuit. The pre-stage constant voltage circuit 110 is provided with a rectifier bridge or an AC-DC circuit to rectify and output the alternating current. In addition, the pre-stage constant voltage circuit 110 can respectively output multiple groups of power supplies with different voltage values through a transformer T1 to supply power to the subsequent circuits.

[0045] The dimming circuit 120 is connected to the second power supply terminal T1_9 to obtain power, and is used to receive a dimming signal and convert the input dimming signal into a PWM signal. The PWM signal is output through the first signal U2_4 terminal of the dimming circuit 120; the dimming circuit 120 can be connected to a control terminal to obtain the voltage value of the dimming signal, convert the dimming signal into a PWM signal, and output it to the post-stage drive circuit 130 for drive output.

[0046] The post-stage drive circuit 130 includes a constant voltage chip U4, a post-stage drive chip U3, and a first capacitor EC1. The power input terminals of the constant voltage chip U4 and the post-stage drive chip U3, and the first capacitor EC1 are all connected to the output terminal of the first diode D1 to obtain power. The post-stage drive chip U3 is provided with a second signal terminal U3_PWM and a drive output terminal U3_C-. The second signal terminal U3_PWM is connected to the first signal terminal U2_4 and the output terminal of the constant voltage chip U4. The drive output terminal U3_C- is connected to the negative electrode of the LED light source 150. The post-stage drive circuit 130 is used to receive a PWM signal and control the negative electrode of the LED light source 150 through the PWM signal, so as to realize operations such as turning on, turning off, and dimming the LED light source 150.

[0047] The anti-backflash circuit 140 is provided with a first power supply terminal and a first control terminal. The first power supply terminal is connected to the first power supply terminal or the second power supply terminal to obtain power. The first control terminal is connected to the first capacitor EC1 or connected between the output terminal of the constant voltage chip U4 and the second signal terminal to control the drive signal output by the post-stage drive circuit 130. The anti-backflash circuit 140 is used to consume the electric quantity of the first capacitor EC1 or pull down the signal of the second signal terminal, so as to control the drive signal output by the post-stage drive circuit 130 to eliminate the backflash phenomenon.

[0048] Embodiment 2:

[0049] Please refer to the appendix Figure 2 In an embodiment of a backflash elimination circuit of the present invention, based on Embodiment 1, the present invention includes the pre-stage constant voltage circuit 110, the dimming circuit 120, and the post-stage drive circuit 130 in Embodiment 1. The present invention also provides a specific implementation scheme of an anti-backflash circuit 140. Specifically, the anti-backflash circuit 140 includes a third diode D3, a third capacitor C3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a triode Q1. The input end of the third diode D3 is the first power supply terminal, and the input end of the third diode D3 is connected to the first power supply terminal. The output end of the third diode D3 is connected to the third capacitor C3, the base of the triode Q1, the fourth resistor R4, and the sixth resistor R6 through the seventh resistor R7. The emitter of the triode Q1 is connected to the fifth resistor R5, and the collector is grounded. The other end of the fifth resistor R5 is the first control terminal and the other end of the fifth resistor R5 is connected to the first capacitor EC1. The other ends of the fourth resistor R4 and the third capacitor C3 are both grounded, and the other end of the sixth resistor R6 is connected to the output terminal of the first diode D1.

[0050] The pre-stage constant voltage circuit 110 includes an AC-DC chip AC-DC and a transformer T1. The input end of the AC-DC chip AC-DC is the first input end, and the output end of the AC-DC chip AC-DC is connected to the transformer T1. The first power supply end and the second power supply end are arranged on the transformer T1 to output a power supply. The pre-stage constant voltage circuit 110 is used to convert the input mains power into the power supply for each circuit of the present invention. The input mains power can be a 220V AC circuit. The pre-stage constant voltage circuit 110 is provided with a rectifier bridge or an AC-DC circuit to rectify and output the alternating current. In addition, the pre-stage constant voltage circuit 110 can output multiple groups of power supplies with different voltage values through the transformer T1 to supply power to the subsequent circuits. Among them, the models of the AC-DC chip AC-DC include but are not limited to NXP TEA2016AAT, EG4318A, Chengxin Micro CX75GD080BL, Chengxin Micro CX75GE030D, Nanxin Technology SC3005N, Nanxin Technology SC3501, etc.

[0051] The dimming circuit 120 includes a dimming chip U1, a first optocoupler U2, a first resistor R1, and a second diode D2. The input end of the second diode D2 is connected to the second power supply end. The dimming chip U1 is provided with a signal input end, a signal output end, and a second power supply end. The second power supply end is connected to the output end of the second diode D2. The signal input end is connected to an external adjustment device. The signal output end is connected to the second end of the first optocoupler U2. The first end of the first optocoupler U2 is connected to the output end of the second diode D2 through the first resistor R1. The fourth end is the first signal end to output a PWM signal to the subsequent stage drive circuit 130, and the third end is grounded. The output end of the second diode D2 is also connected to a second capacitor EC2, and the other end of the second capacitor EC2 is grounded. The signal input end of the dimming chip U1 is used to receive a 0-10V dimming signal. Among them, the chip models for converting voltage signals to PWM signals include but are not limited to GP9303, GP9303M, NCP1397ADR2G, TPS61161DRVR, LN2266PB2MR-G, TL494L-D16-T, OB2532AMP, KP201LGA, SC8701QDER, CL2224IL.

[0052] The subsequent stage drive circuit 130 is also provided with a second resistor R2 and a third resistor R3. The other end of the second resistor R2 is grounded. The third resistor R3 is connected between the output end of the constant voltage chip U4 and the second signal end, or the third resistor R3 is connected between the output end of the constant voltage chip U4 and the first control end. Among them, the chip models of the subsequent stage drive chip U3 include but are not limited to VAS1254, BP2875, iW338, and BP2876D. The model of the constant voltage chip U4 is any one of NS6322B, CL1552, MP1476, and JW5116F.

[0053] The specific working principle of this embodiment is as follows: The current-stage constant-voltage circuit 110 is connected to the AC220V power supply, and the first power supply terminal and the second power supply terminal respectively output DC power supplies outward. Among them, the first power supply terminal outputs DC50V to the positive electrodes of the constant-voltage chip U4, the subsequent-stage drive chip U3, and the LED light source 150 through the first diode D1. The constant-voltage chip U4 converts the input DC50V voltage into DC5V and outputs it to the second signal terminal of the subsequent-stage drive chip U3 through the output terminal of the constant-voltage chip U4 and the third resistor R3. The first end of the second optocoupler U5 of the dimming circuit 120 is provided with an upper-bias conduction voltage by the second power supply terminal, and the subsequent-stage drive chip U3 converts the input voltage into a constant current and outputs it to the negative electrode of the LED light source 150. The first power supply terminal also supplies power to the anti-backflash circuit 140 through the third diode D3. The power transmitted by the third diode D3 supplies reverse bias to the triode Q1 through the seventh resistor R7, and the triode Q1 is cut off, so the anti-backflash circuit 140 does not work. The second power supply terminal outputs DC12V to the dimming chip U1 of the dimming circuit 120 through the second diode D2, and at the same time supplies power to the first end of the first optocoupler U2 through the first resistor R1 to provide an upper-bias voltage for the light-emitting diode of the first optocoupler U2. The dimming chip U1 converts the dimming signal that varies between 0 - 10V at the signal input terminal into a PWM signal and outputs it from the signal output terminal to the second end of the first optocoupler U2. The PWM signal is coupled to the fourth end through the first optocoupler U2 for output, and is supplied to the subsequent-stage drive chip U3 to control the current flowing through the LED light source 150.

[0054] When the signal input terminal of the dimming chip U1 is 9.5V, the signal output terminal outputs a high level; when the signal input terminal is less than 0.5V, the signal output terminal outputs 0V. When the voltage at the signal input terminal varies in the range of 0.5 - 9.5V, the signal output terminal outputs a PWM signal with a corresponding duty cycle. The lower the voltage at the signal input terminal, the smaller the duty cycle of the PWM signal at the signal output terminal. The PWM signal is coupled to the second signal terminal of the subsequent-stage drive chip U3 through the isolation of the first optocoupler U2, so that the drive output terminal of the subsequent-stage drive chip U3 outputs a smaller current, and the brightness of the LED light source 150 is lower; conversely, the drive output terminal of the subsequent-stage drive chip U3 outputs a larger current, and the LED light source 150 is brighter.

[0055] When the voltage at the signal input terminal of the dimming chip U1 is relatively low, such as 1V, the duty cycle of the PWM signal output at the signal output terminal is relatively low, and it is output from the fourth terminal of the first optocoupler U2 to the second signal terminal of the subsequent driver chip U3. At this time, the subsequent driver chip U3 is controlled by the PWM signal to reduce the output current at the drive output terminal and is in the low-brightness state. At this time, when the AC220V input is disconnected, the output voltages of the first diode D1 and the second diode D2 drop rapidly. Since there is no large capacitor at the output terminal of the third diode D3 to store electrical energy, the voltage at the output terminal of the third diode D3 is consumed first, and the voltage on the third capacitor C3 drops rapidly. Since the base voltage of the PNP transistor Q1 is lower than the emitter voltage, it is forward-biased and conducts. The voltage on the first capacitor EC1 forms a loop through the fifth resistor R5, the emitter and collector of the transistor Q1 to the ground, quickly consuming the electrical energy in the first capacitor EC1. At the same time, a part of the electrical energy is still stored in the second capacitor EC2 to supply the dimming chip U1 to work for a short time, so that its signal output terminal still outputs a PWM signal, which is provided to the subsequent driver chip U3 through the first optocoupler U2, so that the subsequent driver chip U3 maintains the current output before power-off to the LED light source 150 until the electrical energy in the first capacitor EC1 is consumed by the fifth resistor R5 and the transistor Q1, and no current passes through the LED light source 150 and it does not emit light.

[0056] The present utility model controls the subsequent drive circuit 130 to output a drive signal to eliminate the flashback phenomenon by setting a flashback prevention circuit 140, taking power through the first power supply terminal of the flashback prevention circuit 140, connecting the first control terminal to the first capacitor EC1, and consuming the power of the first capacitor EC1 through the flashback prevention circuit 140. It effectively avoids the discomfort brought to users by the flashback phenomenon of the lamp and improves the user experience at the same time.

[0057] Embodiment 3:

[0058] Please refer to the appendix Figure 3 The present utility model provides an embodiment of a flashback elimination circuit. Based on Embodiment 1, the present utility model includes the pre-stage constant voltage circuit 110, the dimming circuit 120, and the subsequent drive circuit 130 of Embodiment 1. The present utility model also provides a specific implementation of another flashback prevention circuit 140. Specifically, the flashback prevention circuit 140 includes a third diode D3, a fourth resistor R4, and a second optocoupler U5. The input terminal of the third diode D3 is the first power supply terminal, and the input terminal of the third diode D3 is connected to the second power supply terminal. The output terminal of the third diode D3 is connected to the first terminal of the second optocoupler U5 through the fourth resistor R4. The fourth terminal and the third terminal of the second optocoupler U5 are the first control terminal, and the fourth terminal is connected to the output terminal of the constant voltage chip U4, the third terminal is connected to the second signal terminal, and the second terminal is grounded.

[0059] The pre-stage constant voltage circuit 110 includes an AC-DC chip AC-DC and a transformer T1. The input end of the AC-DC chip AC-DC is the first input end, and the output end of the AC-DC chip AC-DC is connected to the transformer T1. The first power supply end and the second power supply end are arranged on the transformer T1 to output a power supply. The pre-stage constant voltage circuit 110 is used to convert the input mains power into the power supply for each circuit of the present invention. The input mains power can be a 220V AC circuit. The pre-stage constant voltage circuit 110 is provided with a rectifier bridge or an AC-DC circuit to rectify and output the alternating current. In addition, the pre-stage constant voltage circuit 110 can output multiple groups of power supplies with different voltage values through the transformer T1 to supply power to the subsequent circuits. Among them, the models of the AC-DC chip AC-DC include but are not limited to NXP TEA2016AAT, EG4318A, CX75GD080BL of Chengxin Microelectronics, CX75GE030D of Chengxin Microelectronics, SC3005N of Nanxinc Technology, SC3501 of Nanxinc Technology, etc.

[0060] The dimming circuit 120 includes a dimming chip U1, a first optocoupler U2, a first resistor R1, and a second diode D2. The input end of the second diode D2 is connected to the second power supply end. The dimming chip U1 is provided with a signal input end, a signal output end, and a second power supply end. The second power supply end is connected to the output end of the second diode D2. The signal input end is connected to an external adjustment device, and the signal output end is connected to the second end of the first optocoupler U2. The first end of the first optocoupler U2 is connected to the output end of the second diode D2 through the first resistor R1. The fourth end is the first signal end to output a PWM signal to the subsequent stage drive circuit 130, and the third end is grounded. The output end of the second diode D2 is also connected to a second capacitor EC2, and the other end of the second capacitor EC2 is grounded. The signal input end of the dimming chip U1 is used to receive a 0-10V dimming signal. Among them, the chip models for converting voltage signals to PWM signals include but are not limited to GP9303, GP9303M, NCP1397ADR2G, TPS61161DRVR, LN2266PB2MR-G, TL494L-D16-T, OB2532AMP, KP201LGA, SC8701QDER, CL2224IL.

[0061] The subsequent stage drive circuit 130 is also provided with a second resistor R2 and a third resistor R3. The other end of the second resistor R2 is grounded. The third resistor R3 is connected between the output end of the constant voltage chip U4 and the second signal end, or the third resistor R3 is connected between the output end of the constant voltage chip U4 and the first control end. Among them, the chip models of the subsequent stage drive chip U3 include but are not limited to VAS1254, BP2875, iW338, and BP2876D. The model of the constant voltage chip U4 is any one of NS6322B, CL1552, MP1476, and JW5116F.

[0062] The specific working principle of this embodiment is as follows: The current-stage constant-voltage circuit 110 is connected to the AC220V power supply, and the first power supply terminal and the second power supply terminal respectively output DC power supplies to the outside. Among them, the first power supply terminal outputs DC50V to the positive electrodes of the constant-voltage chip U4, the post-stage drive chip U3, and the LED light source 150 through the first diode D1. The constant-voltage chip U4 converts the input DC50V voltage into DC5V, and through the output terminal of the constant-voltage chip U4, it passes through the third resistor R3 and is input from the 4th pin of the second optocoupler U5 to the 3rd pin, and then output to the second signal terminal of the post-stage drive chip U3. The first end of the second optocoupler U5 of the dimming circuit 120 is provided with an upper-bias conduction voltage by the second power supply terminal. The post-stage drive chip U3 converts the input voltage into a constant current and outputs it to the negative electrode of the LED light source 150. The second power supply terminal outputs DC12V to the dimming chip U1 of the dimming circuit 120 through the second diode D2, and at the same time passes through the first resistor R1 to the first end of the first optocoupler U2 to provide an upper-bias voltage for the light-emitting diode of the first optocoupler U2. The dimming chip U1 converts the dimming signal that varies between 0 - 10V at the signal input terminal into a PWM signal, and outputs it from the signal output terminal to the second end of the first optocoupler U2. The PWM signal is coupled to the fourth end through the first optocoupler U2 for output, and is given to the post-stage drive chip U3 to control the current flowing through the LED light source 150. The second power supply terminal also supplies power to the anti-backflash circuit 140 through the third diode D3. The output terminal of the third diode D3 passes through the fourth resistor R4 to provide a conduction voltage to the first end of the second optocoupler U5, and then reaches the ground through the second end of the second optocoupler U5.

[0063] When the signal input terminal of the dimming chip U1 is 9.5V, the signal output terminal outputs a high level; when the signal input terminal is less than 0.5V, the signal output terminal outputs 0V. When the voltage at the signal input terminal varies within the range of 0.5 - 9.5V, the signal output terminal outputs a PWM signal with a corresponding duty cycle. The lower the voltage at the signal input terminal, the smaller the duty cycle of the PWM signal at the signal output terminal. The PWM signal is coupled to the second signal terminal of the post-stage drive chip U3 through the isolation of the first optocoupler U2, so that the drive output terminal of the post-stage drive chip U3 outputs a smaller current, and the brightness of the LED light source 150 is lower; conversely, the drive output terminal of the post-stage drive chip U3 outputs a larger current, and the LED light source 150 is brighter.

[0064] When the voltage at the signal input terminal of the dimming chip U1 is low, for example, when it is 1V, the duty cycle of the PWM signal output at the signal output terminal is low, and it is output from the fourth terminal of the first optocoupler to the second signal terminal of the subsequent driver chip U3. At this time, the subsequent driver chip U3 is controlled by the PWM signal, reducing the output current at the drive output terminal and being in the low brightness state. At this time, when the AC220V input is disconnected, the output voltages of the first diode D1 and the second diode D2 decrease rapidly. Since there is no large capacitor at the output terminal of the third diode D3 to store electrical energy, the voltage at the output terminal of the third diode D3 decreases rapidly, and there is no conduction voltage at the first terminal of the second optocoupler U5, and the internal light-emitting diode is cut off. The voltage at the output terminal of the constant voltage chip U4 cannot be given to the second signal terminal through the third terminal and the fourth terminal of the second optocoupler U5. Through the second resistor R2, the second signal terminal is pulled low to the ground, turning off the drive output terminal of the subsequent drive circuit 130, and no current passes through the LED light source 150 and it does not emit light. At this time, the PWM signal at the second signal terminal is controlled by the second optocoupler U5 until the electric quantity in the first capacitor EC1 is exhausted, and there will be no flashback phenomenon before the next power-on.

[0065] The flashback elimination circuit provided by the present utility model, by setting the anti-flashback circuit 140, takes power by connecting the first power supply terminal of the anti-flashback circuit 140 to the second power supply terminal, and the first control terminal is connected between the output terminal of the constant voltage chip U4 and the second signal terminal. The signal at the second signal terminal is pulled low through the anti-flashback circuit 140, thereby controlling the subsequent drive circuit 130 to output a drive signal to eliminate the flashback phenomenon. It effectively avoids the discomfort brought to users by the flashback phenomenon of the lamp, and at the same time improves the user experience.

[0066] Embodiment 4:

[0067] In this embodiment, the present utility model provides a lamp, including an integrated circuit board and an LED light source 150. The integrated circuit board integrates the flashback elimination circuit of the above-mentioned Embodiments 1-3, and the integrated circuit board is electrically connected to the LED light source 150 through the flashback elimination circuit. Specifically, the flashback elimination circuit is integrated in the integrated circuit board of the lamp. The integrated circuit board can be located in the drive part of the lamp or the circuit board part of the whole lamp. The opening and closing of the LED light source 150 are realized through the flashback elimination circuit. When the LED light source 150 is turned on, the dimming circuit 120 controls the brightness adjustment of the lamp by receiving a 0-10V dimming signal. And when the LED light source 150 is turned off, the electric quantity of the first capacitor EC1 is consumed or the signal at the second signal terminal is pulled low through the anti-flashback circuit 140, thereby controlling the subsequent drive circuit 130 to output a drive signal to eliminate the flashback phenomenon.

[0068] Embodiment 5:

[0069] In this embodiment, the present utility model provides an illumination system, which includes a control terminal and the lamp in Embodiment 4; the control terminal is electrically connected to the driving power supply of the lamp, and / or the control terminal exchanges information with the driving power supply. In this embodiment, the control terminal can be a conventional control panel (such as a mechanical switch panel), a smart control panel or a remote control. When the control terminal is a conventional control panel, the control terminal is electrically connected to the control unit of the lamp. When the control terminal is a smart control panel or a remote control, a first wireless communication module is provided on the control unit, and a second wireless communication module is provided on the control terminal; the control terminal is electrically connected to the control unit, and / or the first wireless communication module exchanges information with the second wireless communication module. In addition, the control terminal can also be a smart mobile terminal (such as a mobile phone, a tablet computer, a smart wearable device, etc.), or an artificial intelligence robot. It can be seen that through the interaction between the control terminal and the lamp, the intelligent adjustment of the lighting device can be realized, the intelligent lighting function with multiple scenarios and multiple uses is realized, and the occurrence of backflash phenomenon is prevented after the lamp is turned off, improving the user experience.

[0070] In the present utility model, unless otherwise clearly defined and limited, the terms "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0071] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of this utility model is usually placed. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0072] In addition, the terms "horizontal", "vertical", "hanging", etc. do not mean that the components are required to be absolutely horizontal or hanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0073] In the present utility model, unless otherwise clearly stipulated and defined, the first feature being above or below the second feature may include direct contact between the first and second features, or may include contact between the first and second features not being direct but through additional features therebetween. Moreover, the first feature being above, on top of, and over the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being below, beneath, and under the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is less than that of the second feature.

[0074] Although the description of the present utility model is made in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications, and variations based on the above content. Therefore, all such substitutions, improvements, and variations are included within the spirit and scope of the appended claims.

Claims

1. A flashback elimination circuit, characterized in that, Comprising: A pre-stage constant voltage circuit, which is provided with a first input terminal, a first power supply terminal and a second power supply terminal. The first input terminal is connected to the input mains electricity, and the first power supply terminal is connected to the positive electrode of the LED light source through a first diode; A dimming circuit, which is connected to the second power supply terminal to draw power, is used for receiving a dimming signal and converting the dimming signal into a PWM signal, and the PWM signal is output through the first signal terminal of the dimming circuit; A post-stage driving circuit, which includes a constant voltage chip, a post-stage driving chip and a first capacitor. The power input terminals of the constant voltage chip, the post-stage driving chip and the first capacitor are all connected to the output terminal of the first diode to draw power. The post-stage driving chip is provided with a second signal terminal and a driving output terminal. The second signal terminal is connected to the first signal terminal and the output terminal of the constant voltage chip, and the driving output terminal is connected to the negative electrode of the LED light source; And an anti-backflash circuit, which is provided with a first power supply terminal and a first control terminal. The first power supply terminal is connected to the first power supply terminal or the second power supply terminal to draw power, and the first control terminal is connected to the first capacitor, or connected between the output terminal of the constant voltage chip and the second signal terminal to control the driving signal output by the post-stage driving circuit.

2. The flashback elimination circuit according to claim 1, wherein The anti-backflash circuit includes a third diode, a third capacitor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a triode. The input terminal of the third diode is the first power supply terminal, and the input terminal of the third diode is connected to the first power supply terminal. The output terminal of the third diode is connected to the third capacitor, the base of the triode, the fourth resistor and the sixth resistor through the seventh resistor; The emitter of the triode is connected to the fifth resistor, and the collector is grounded; the other end of the fifth resistor is the first control terminal and the other end of the fifth resistor is connected to the first capacitor; The other ends of the fourth resistor and the third capacitor are both grounded, and the other end of the sixth resistor is connected to the output terminal of the first diode.

3. The flashback elimination circuit according to claim 1, wherein The anti-backflash circuit includes a third diode, a fourth resistor and a second optocoupler. The input terminal of the third diode is the first power supply terminal, and the input terminal of the third diode is connected to the second power supply terminal. The output terminal of the third diode is connected to the first end of the second optocoupler through the fourth resistor; The fourth end and the third end of the second optocoupler are the first control terminal, and the fourth end is connected to the output terminal of the constant voltage chip, the third end is connected to the second signal terminal, and the second end is grounded.

4. The flashback elimination circuit according to claim 2 or 3, characterized in that, The pre-stage constant voltage circuit includes an AC-DC chip and a transformer. The input terminal of the AC-DC chip is the first input terminal and the output terminal of the AC-DC chip is connected to the transformer; The first power supply terminal and the second power supply terminal are arranged on the transformer to output a power supply.

5. The flashback elimination circuit according to claim 4, wherein, The dimming circuit includes a dimming chip, a first optocoupler, a first resistor and a second diode. The input terminal of the second diode is connected to the second power supply terminal; The dimming chip is provided with a signal input terminal, a signal output terminal and a second power supply terminal. The second power supply terminal is connected to the output terminal of the second diode. The signal input terminal is connected to an external adjustment device, and the signal output terminal is connected to the second end of the first optocoupler; The first end of the first optocoupler is connected to the output end of the second diode through a first resistor. The fourth end is the first signal end for outputting a PWM signal to the subsequent driving circuit, and the third end is grounded.

6. The flashback elimination circuit according to claim 5, wherein The output end of the second diode is also connected to a second capacitor, and the other end of the second capacitor is grounded.

7. The flashback elimination circuit according to claim 6, wherein The signal input end of the dimming chip is used to receive a 0-10V dimming signal.

8. The flash cancellation circuit according to claim 6, wherein The subsequent driving circuit is also provided with a second resistor and a third resistor. The other end of the second resistor is grounded. The third resistor is connected between the output end of the constant voltage chip and the second signal end, or the third resistor is connected between the output end of the constant voltage chip and the first control end.

9. A lighting fixture, characterized in that, It includes an integrated circuit board and an LED light source. The integrated circuit board integrates the backflash elimination circuit described in any one of claims 1-8, and the integrated circuit board is electrically connected to the LED light source through the backflash elimination circuit.

10. A lighting system, comprising a control terminal, characterized in that: The lighting system further includes the lamp as described in claim 9; The control terminal is electrically connected to the driving power supply of the lamp, and / or The control terminal exchanges information with the driving power supply.

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