Flickback elimination circuit, lamp and lighting system

Abstract

The invention 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 invention, 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 invention belongs to the technical field of lighting, and in particular relates to a flashback elimination circuit, a lamp and a lighting system. Background Art

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

[0003] In order to solve the deficiencies of the prior art, the present invention provides a flashback elimination circuit, a lamp and a lighting system. The flashback elimination circuit is powered by connecting the first power supply end of the anti-flashback circuit to the first power supply end or the second power supply end, and the first control end is connected to the first capacitor or connected between the output end of the constant voltage chip and the second signal end to control the subsequent driving circuit to output a driving signal, thereby avoiding the flashback phenomenon.

[0004] The technical effects to be achieved by the present invention are achieved through the following aspects: In a first aspect, the present invention provides a flashback elimination circuit, comprising: The front-stage constant voltage circuit is provided with a first input terminal, a first power supply terminal and a second power supply terminal, wherein the first input terminal is connected to the input mains, and the first power supply terminal is connected to the positive electrode of the LED light source through a first diode; a dimming circuit, connected to the second power supply terminal to take power, configured to receive a dimming signal and convert the dimming signal into a PWM signal, wherein the PWM signal is output through the first signal terminal of the dimming circuit; A rear-stage driving circuit, comprising a constant voltage chip, a rear-stage driving chip and a first capacitor, wherein the power input terminal 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, and the rear-stage driving chip is provided with a second signal terminal and a driving output terminal, wherein 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-backlash circuit is provided with a first power supply end and a first control end, the first power supply end is connected to the first power supply end or the second power supply end to obtain power, and the first control end is connected to the first capacitor or connected between the output end of the constant voltage chip and the second signal end to control the subsequent drive circuit to output a drive signal.

[0005] In some implementations, the backlighting prevention 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 end of the third diode is the first power supply end, and the input end of the third diode is connected to the first power supply end, and the output end of the third diode is connected to the third capacitor, the base of the transistor, the fourth resistor and the sixth resistor through the seventh resistor; The emitter of the transistor is connected to the fifth resistor, and the collector is grounded; the other end of the fifth resistor is the first control end 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 end of the first diode.

[0006] In some implementations, the anti-flashback circuit includes a third diode, a fourth resistor, and a second optical coupler. The input end of the third diode is the first power supply end, and the input end of the third diode is connected to the second power supply end, and the output end of the third diode is connected to the first end of the second optical coupler through a fourth resistor; The fourth end and the third end of the second optical coupler are the first control end, and the fourth end is connected to the output end of the constant voltage chip, the third end is connected to the second signal end, and the second end is grounded.

[0007] In some implementations, the front-stage constant voltage circuit includes an AC-DC chip and a transformer. The input end of the AC-DC chip is a first input end and the output end 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 power supply.

[0008] In some implementations, the dimming circuit includes a dimming chip, a first optocoupler, a first resistor, and a second diode. An input end of the second diode is connected to the second power supply end; 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 terminal of the first optical coupler; The first end of the first optical coupler is connected to the output end of the second diode through a first resistor, the fourth end is a first signal end that outputs a PWM signal to a subsequent drive circuit, and the third end is grounded.

[0009] In some implementations, the output end of the second diode is also connected to a second capacitor, and the other end of the second capacitor is grounded.

[0010] In some implementations, the signal input terminal of the dimming chip is used to receive a 0-10V dimming signal.

[0011] In some implementations, the post-stage 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.

[0012] In a second aspect, the present invention provides a lamp, comprising an integrated circuit board and an LED light source, wherein the integrated circuit board is integrated with the above-mentioned flashback elimination circuit, and the integrated circuit board is electrically connected to the LED light source through the flashback elimination circuit.

[0013] In this implementation, the flashback elimination circuit is integrated into 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 entire lamp. The LED light source is turned on and off by 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.

[0014] In a third aspect, the present invention provides a lighting system, comprising a control terminal and the above-mentioned lamp; The control terminal is electrically connected to a driving power source of the lamp, and / or The control terminal exchanges information with the driving power supply.

[0015] In this implementation, the lighting system can be applied to smart lighting in various usage modes and application scenarios. By controlling the interaction between the terminal and the lamp, intelligent adjustment of the lighting device can be achieved, realizing multi-scene and multi-purpose smart lighting functions, and preventing the occurrence of flashback after the lamp is turned off, thereby improving the user experience.

[0016] In summary, the present invention has at least the following benefits: The flashback elimination circuit provided by the present invention is provided with a flashback prevention circuit, wherein the first power supply end of the flashback prevention circuit is connected to the first power supply end or the second power supply end to obtain power, the first control end is connected to the first capacitor or is connected between the output end of the constant voltage chip and the second signal end, and the flashback prevention 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. This effectively avoids the discomfort caused to users by the flashback phenomenon of the lamp, and improves the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the flashback elimination circuit of embodiment 1 of the present invention.

[0018] Figure 2 This is a first circuit schematic diagram of a flashback elimination circuit according to Embodiment 2 of the present invention.

[0019] Figure 3 This is a second circuit schematic diagram of the flashback elimination circuit according to Embodiment 3 of the present invention.

[0020] Markings in the figure: 110, front stage constant voltage circuit; 120, dimming circuit; 130, rear stage driving circuit; 140, backlighting protection circuit; 150, LED light source; AC-DC, AC-DC chip; T1, transformer; D1, first diode; D2, second diode; D3, third diode; U1, dimming chip; U2, first optocoupler; U3, post-driver 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, transistor. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of them.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0023] Embodiment 1: Please see attached Figure 1 , this embodiment provides a flashback elimination circuit, including a front-stage constant voltage circuit 110, a dimming circuit 120, a rear-stage driving circuit 130 and an anti-flashback circuit 140, to avoid the flashback phenomenon. Specifically, the front-stage constant voltage circuit 110 is provided with a first input terminal, a first power terminal T1_13 and a second power terminal T1_9. The first input terminal is connected to the input mains power, and the first power terminal T1_13 is connected to the positive electrode of the LED light source 150 through the first diode D1; the front-stage constant voltage circuit 110 is used to convert the input mains power into the power supply of each circuit of the embodiment of the present invention. The input mains power can be a 220V AC circuit. The front-stage constant voltage circuit 110 is provided with a rectifier bridge or an AC-DC circuit to rectify the AC power and output it. In addition, the front-stage constant voltage circuit 110 can output multiple groups of power supplies with different voltage values ​​through the transformer T1 to power the back-end circuit.

[0024] The dimming circuit 120 is connected to the second power supply terminal T1_9 for power supply, and is used for receiving the dimming signal and converting the input dimming signal into a PWM signal, and the PWM signal is output through the first signal U2_4 terminal of the dimming circuit 120; the dimming circuit 120 is used for connecting to the control terminal, obtaining the voltage value of the dimming signal, converting the dimming signal into a PWM signal, and outputting it to the subsequent driving circuit 130 for driving output.

[0025] The post-stage driving circuit 130 includes a constant voltage chip U4, a post-stage driving chip U3 and a first capacitor EC1. The power input terminals of the constant voltage chip U4, the post-stage driving chip U3 and the first capacitor EC1 are all connected to the output terminal of the first diode D1 for power. The post-stage driving chip U3 is provided with a second signal terminal U3_PWM and a driving 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 driving output terminal U3_C- is connected to the cathode of the LED light source 150. The post-stage driving circuit 130 is used to receive a PWM signal and control the cathode of the LED light source 150 through the PWM signal, thereby realizing operations such as turning on, off and dimming the LED light source 150.

[0026] The anti-flashback circuit 140 is provided with a first power supply end and a first control end, the first power supply end is connected to the first power supply end or the second power supply end to obtain power, and the first control end is connected to the first capacitor EC1 or connected between the output end of the constant voltage chip U4 and the second signal end to control the output of the driving signal of the subsequent drive circuit 130. The anti-flashback circuit 140 is used to consume the power of the first capacitor EC1 or pull down the signal of the second signal end, thereby controlling the subsequent drive circuit 130 to output the driving signal to eliminate the flashback phenomenon.

[0027] Embodiment 2: Please see attached Figure 2, an embodiment of a flashback elimination circuit of the present invention, based on embodiment 1, the present invention includes a front-stage constant voltage circuit 110, a dimming circuit 120 and a rear-stage driving circuit 130 of embodiment 1, and the present invention also provides a specific implementation scheme of an anti-flashback circuit 140, specifically, the anti-flashback 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 transistor Q1, the input end of the third diode D3 is a first power supply end, and the input end of the third diode D3 is connected to the first power supply end, the output end of the third diode D3 is connected to the third capacitor C3, the base of the transistor Q1, the fourth resistor R4 and the sixth resistor R6 through the seventh resistor R7; the emitter of the transistor Q1 is connected to the fifth resistor R5, and the collector is grounded; the other end of the fifth resistor R5 is a first control end 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 end of the first diode D1.

[0028] The front-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 a 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 the power supply. The front-stage constant voltage circuit 110 is used to convert the input mains into the power supply of each circuit of the present invention. The input mains can be a 220V AC circuit. The front-stage constant voltage circuit 110 is provided with a rectifier bridge or an AC-DC circuit to rectify the AC power and output it. In addition, the front-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 back-end circuit. Among them, the models of the AC-DC chip AC-DC include but are not limited to NXP TEA2016AAT, EG4318A, Chengxinwei CX75GD080BL, Chengxinwei CX75GE030D, Nanxin Technology SC3005N, Nanxin Technology SC3501, etc.

[0029] 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 drive circuit 130, and the third end is grounded. The output end of the second diode D2 is also connected to the 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 into PWM signals include but are not limited to GP9303, GP9303M, NCP1397ADR2G, TPS61161DRVR, LN2266PB2MR-G, TL494L-D16-T, OB2532AMP, KP201LGA, SC8701QDER, and CL2224IL.

[0030] The rear-stage driving 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 model of the rear-stage driving chip U3 includes but is 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.

[0031] The specific working principle of this embodiment is as follows: when the current constant voltage circuit 110 is connected to the AC220V power supply, the first power supply end and the second power supply end respectively output a DC power supply to the outside. Among them, the first power supply end outputs DC50V to the positive electrode of the constant voltage chip U4, the subsequent driver chip U3 and the LED light source 150 through the first diode D1, and the constant voltage chip U4 converts the input DC50V voltage into a DC 5V and outputs it to the second signal end of the subsequent driver chip U3 through the output end of the constant voltage chip U4 through the third resistor R3. The first end of the second optical coupler U5 of the dimming circuit 120 is provided with an upper bias conduction voltage by the second power supply end, and the subsequent driver 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 end is also provided to the anti-backward lightning circuit 140 through the third diode D3, and the power transmitted by the third diode D3 is provided to the transistor Q1 through the seventh resistor R7 to provide reverse bias, and the transistor Q1 is cut off, and the anti-backward lightning circuit 140 does not work. The second power supply end outputs DC12V to the dimming chip U1 of the dimming circuit 120 through the second diode D2, and at the same time is given to the first end of the first optocoupler U2 through the first resistor R1, providing an upper bias voltage to the light-emitting diode of the first optocoupler U2. The dimming chip U1 converts the dimming signal varying between 0-10V at the signal input end into a PWM signal, and outputs it to the second end of the first optocoupler U2 from the signal output end. The PWM signal is coupled to the fourth end through the first optocoupler U2 for output, and is given to the subsequent driver chip U3 to control the current flowing through the LED light source 150.

[0032] 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. The voltage variation range of the signal input terminal is between 0.5-9.5V, and the signal output terminal outputs a PWM signal corresponding to the 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 isolated and coupled to the second signal terminal of the subsequent driver chip U3 through the first optical coupler U2, so that the output current of the driver output terminal of the subsequent driver chip U3 is smaller, and the brightness of the LED light source 150 is lower; conversely, the output current of the driver output terminal of the subsequent driver chip U3 is larger, and the LED light source 150 is brighter.

[0033] When the voltage at the signal input end of the dimming chip U1 is low, such as 1V, the duty cycle of the PWM signal output from the signal output end is relatively low, and is output from the fourth end of the first optical coupler U2 to the second signal end 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 of the driver output end and is in a low brightness state; at this time, the AC220V input is disconnected, and the output voltages of the first diode D1 and the second diode D2 drop rapidly. Since there is no large capacitor to store electrical energy at the output end of the third diode D3, the voltage at the output end of the third diode D3 is consumed first, and the voltage on the third capacitor C3 drops rapidly. Since Q1 is a PNP transistor base electrode, the voltage at the output end of the third diode D3 is consumed first, and the voltage on the third capacitor C3 drops rapidly. The voltage is lower than the transmitter voltage, so that it is forward-biased and turned on. The voltage on the first capacitor EC1 forms a loop through the fifth resistor R5 and the emitter and collector of the transistor Q1 to the ground, and the electric energy in the first capacitor EC1 is quickly consumed. At the same time, a part of the electric energy is stored in the second capacitor EC2 to supply the dimming chip U1 to work for a short time, so that its signal output end still outputs a PWM signal, which is provided to the subsequent driver chip U3 through the first optical coupler U2, so that the subsequent driver chip U3 maintains the current before power failure and outputs it to the LED light source 150, until the electric energy in the first capacitor EC1 is consumed by the fifth resistor R5 and the transistor Q1, and the LED light source 150 does not emit light without current passing through it.

[0034] The present invention provides a flashback prevention circuit 140, connects the first power supply end of the flashback prevention circuit 140 to take power, connects the first control end to the first capacitor EC1, and consumes the power of the first capacitor EC1 through the flashback prevention circuit 140, thereby controlling the subsequent drive circuit 130 to output a drive signal to eliminate the flashback phenomenon. This effectively avoids the discomfort caused to users by the flashback phenomenon of the lamp, and improves the user experience.

[0035] Embodiment 3: Please see attached Figure 3 The present invention provides an embodiment of a flashback elimination circuit. Based on Embodiment 1, the present invention includes a front-stage constant voltage circuit 110, a dimming circuit 120 and a rear-stage driving circuit 130 of Embodiment 1. The present invention also provides another specific implementation scheme of an anti-flashback circuit 140. Specifically, the anti-flashback circuit 140 includes a third diode D3, a fourth resistor R4 and a second optocoupler U5. The input end of the third diode D3 is a first power supply end, and the input end of the third diode D3 is connected to the second power supply end. The output end of the third diode D3 is connected to the first end of the second optocoupler U5 through the fourth resistor R4; the fourth end and the third end of the second optocoupler U5 are the first control ends, and the fourth end is connected to the output end of the constant voltage chip U4, the third end is connected to the second signal end, and the second end is grounded.

[0036] The front-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 a 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 the power supply. The front-stage constant voltage circuit 110 is used to convert the input mains into the power supply of each circuit of the present invention. The input mains can be a 220V AC circuit. The front-stage constant voltage circuit 110 is provided with a rectifier bridge or an AC-DC circuit to rectify the AC power and output it. In addition, the front-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 back-end circuit. Among them, the models of the AC-DC chip AC-DC include but are not limited to NXP TEA2016AAT, EG4318A, Chengxinwei CX75GD080BL, Chengxinwei CX75GE030D, Nanxin Technology SC3005N, Nanxin Technology SC3501, etc.

[0037] 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 drive circuit 130, and the third end is grounded. The output end of the second diode D2 is also connected to the 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 into PWM signals include but are not limited to GP9303, GP9303M, NCP1397ADR2G, TPS61161DRVR, LN2266PB2MR-G, TL494L-D16-T, OB2532AMP, KP201LGA, SC8701QDER, and CL2224IL.

[0038] The rear-stage driving 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 model of the rear-stage driving chip U3 includes but is 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.

[0039] The specific working principle of this embodiment is as follows: when the current constant voltage circuit 110 is connected to the AC220V power supply, the first power supply end and the second power supply end output DC power to the outside respectively. Among them, the first power supply end outputs DC50V to the constant voltage chip U4, the subsequent driver chip U3 and the positive electrode of the LED light source 150 through the first diode D1, and the constant voltage chip U4 converts the input DC50V voltage into DC 5V and passes through the output end of the constant voltage chip U4 through the third resistor R3, and inputs the 3rd pin from the 4th pin of the second optical coupler U5, and then outputs it to the second signal end of the subsequent driver chip U3. The first end of the second optical coupler U5 of the dimming circuit 120 is provided with an upper bias conduction voltage by the second power supply end, and the subsequent driver 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, it is given to the first end of the first optical coupler U2 through the first resistor R1, and the light-emitting diode of the first optical coupler U2 is provided with an upper bias voltage. The dimming chip U1 converts the dimming signal between 0-10V of the signal input terminal into a PWM signal, and outputs it to the second end of the first optical coupler U2 from the signal output terminal. The PWM signal is coupled to the fourth end through the first optical coupler U2 for output, and is given to the subsequent driver chip U3 to control the current flowing through the LED light source 150. The second power supply terminal also provides the anti-reverse lightning circuit 140 through the third diode D3. The output end of the third diode D3 provides the first end of the second optical coupler U5 through the fourth resistor R4 to provide a conduction voltage, and then reaches the ground through the second end of the second optical coupler U5.

[0040] 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. The voltage variation range of the signal input terminal is between 0.5-9.5V, and the signal output terminal outputs a PWM signal corresponding to the 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 isolated and coupled to the second signal terminal of the subsequent driver chip U3 through the first optical coupler U2, so that the output current of the driver output terminal of the subsequent driver chip U3 is smaller, and the brightness of the LED light source 150 is lower; conversely, the output current of the driver output terminal of the subsequent driver chip U3 is larger, and the LED light source 150 is brighter.

[0041] When the voltage of the signal input terminal of the dimming chip U1 is low, such as 1V, the duty cycle of the PWM signal output from the signal output terminal is relatively low, and it is output from the fourth terminal of the first optical coupler 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 of the drive output terminal, and is in a low brightness state; at this time, the AC220V input is disconnected, and the output voltage of the first diode D1 and the second diode D2 decreases rapidly. Since there is no large capacitor to store electrical energy at the output terminal of the third diode D3, the output voltage of the third diode D3 decreases rapidly, and the first terminal of the second optical coupler U5 has no conduction voltage, the internal light-emitting diode is cut off, and the voltage of 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 optical coupler U5. The second signal terminal is pulled down to the ground through the second resistor R2, so that the drive output terminal of the subsequent driver circuit 130 is turned off, and the LED light source 150 has no current and does not emit light. At this time, the PWM signal of the second signal terminal is controlled by the second optical coupler U5 until the power in the first capacitor EC1 is exhausted, and there will be no flashback phenomenon before the next startup.

[0042] The flashback elimination circuit provided by the present invention is provided with an anti-flashback circuit 140, the first power supply end of the anti-flashback circuit 140 is connected to the second power supply end to obtain power, the first control end is connected between the output end of the constant voltage chip U4 and the second signal end, and the signal of the second signal end is pulled down by the anti-flashback circuit 140, thereby controlling the subsequent drive circuit 130 to output a drive signal to eliminate the flashback phenomenon. The discomfort caused to the user by the flashback phenomenon of the lamp is effectively avoided, and the user experience is improved at the same time.

[0043] Embodiment 4: In this embodiment, the present invention provides a lamp, including an integrated circuit board and an LED light source 150, the integrated circuit board is integrated with 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, and 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 150 is turned on and off by 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 anti-flashback circuit 140 consumes the power of the first capacitor EC1 or pulls down the signal of the second signal end, thereby controlling the subsequent driving circuit 130 to output a driving signal to eliminate the flashback phenomenon.

[0044] Embodiment 5: In this embodiment, the present invention provides a lighting system, including a control terminal and a lamp of embodiment 4; the control terminal is electrically connected to a driving power supply of the lamp, and / or the control terminal and the driving power supply exchange information. In this embodiment, the control terminal can be a conventional control panel (such as a mechanical switch panel), an intelligent 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 an intelligent 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 and the second wireless communication module exchange information. In addition, the control terminal can also be an intelligent mobile terminal (such as a mobile phone, a tablet computer, an intelligent wearing device, etc.), and can also be 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 of multiple scenes and multiple uses can be realized, and the flashback phenomenon can be prevented after the lamp is turned off, thereby improving the user experience.

[0045] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0047] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0048] In the present invention, unless otherwise clearly specified and limited, a first feature being above or below a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. Moreover, a first feature being above, above, and above a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being below, below, and below a second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0049] Although the present invention is described in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications and changes according to the above content. Therefore, all such substitutions, improvements and changes are included in the spirit and scope of the appended claims.

Claims

1. A flashback elimination circuit, characterized in that: include: The front-stage constant voltage circuit is provided with a first input terminal, a first power supply terminal and a second power supply terminal, wherein the first input terminal is connected to the input mains, and the first power supply terminal is connected to the positive electrode of the LED light source through a first diode; a dimming circuit, connected to the second power supply terminal to take power, configured to receive a dimming signal and convert the dimming signal into a PWM signal, wherein the PWM signal is output through the first signal terminal of the dimming circuit; A rear-stage driving circuit, comprising a constant voltage chip, a rear-stage driving chip and a first capacitor, wherein the power input terminal 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, and the rear-stage driving chip is provided with a second signal terminal and a driving output terminal, wherein 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 a back-flash protection circuit is provided with a first power supply end and a first control end, the first power supply end is connected to the first power supply end or the second power supply end to obtain power, the first control end is connected to the first capacitor, or is connected between the output end of the constant voltage chip and the second signal end to control the subsequent drive circuit to output a drive signal.

2. The flashback elimination circuit according to claim 1, characterized in that: The anti-flashback 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 end of the third diode is the first power supply end, and the input end of the third diode is connected to the first power supply end, and the output end of the third diode is connected to the third capacitor, the base of the transistor, the fourth resistor and the sixth resistor through the seventh resistor; The emitter of the transistor is connected to the fifth resistor, and the collector is grounded; the other end of the fifth resistor is the first control end 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 end of the first diode.

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

4. The flashback elimination circuit according to claim 2 or 3, characterized in that: The front-stage constant voltage circuit includes an AC-DC chip and a transformer. The input end of the AC-DC chip is a first input end and the output end 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 power supply.

5. The flashback elimination circuit according to claim 4, characterized in that: The dimming circuit includes a dimming chip, a first optocoupler, a first resistor and a second diode. An input end of the second diode is connected to the second power supply end; 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 terminal of the first optical coupler; The first end of the first optical coupler is connected to the output end of the second diode through a first resistor, the fourth end is a first signal end that outputs a PWM signal to a subsequent drive circuit, and the third end is grounded.

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

7. The flashback elimination circuit according to claim 6, characterized in that: The signal input terminal of the dimming chip is used to receive a 0-10V dimming signal.

8. The flashback elimination circuit according to claim 6, characterized in that: The post-stage 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 lamp, characterized in that: It comprises an integrated circuit board and an LED light source, wherein the integrated circuit board is integrated with the flashback elimination circuit described in any one of claims 1 to 8, and the integrated circuit board is electrically connected to the LED light source through the flashback elimination circuit.

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

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