Silicon controlled rectifier dimming device of LED driving power supply

Abstract

The invention discloses a silicon controlled rectifier dimming device of an LED driving power supply. The silicon controlled rectifier dimming device comprises a voltage transformation unit, a rectification filtering unit, a first switch unit, a first filtering unit, a first voltage stabilization unit, a phase detection module and a control unit, the pre-stage circuit carries out voltage conversion and outputs steamed bun waves subjected to phase cutting control, reflected voltage of the voltage transformation unit is rectified into pulse waves through the rectification unit, the pulse waves are subjected to voltage division through the voltage distribution unit to drive the second switch unit, the pulse waves are converted into square waves with a duty ratio, and the square waves are converted into square waves with the duty ratio. The control unit outputs a corresponding driving waveform to the first switch unit according to the size of the square wave duty ratio, and the first switch unit is driven to carry out voltage chopping, so that the output current is changed in a range of 1-100% for dimming. The phase detection module is matched with the rectification filtering unit to filter clutters in the voltage signals so as to improve the detection precision, and the first filtering unit is matched with the first switch unit to fill up the energy lost by the waveform, so that the output current is smoother.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of silicon-controlled light modulation, and particularly relates to a silicon-controlled light modulation device of an LED driving power supply. BACKGROUND

[0002] The LED driving power supply on the market generally adopts a silicon-controlled phase-cut light modulation mode, and the output current of the LED light source is adjusted by detecting the phase angle output of the silicon-controlled rectifier. The silicon-controlled light modulation mode is widely applied to the technical field of lighting due to low use cost and convenient light modulation. However, it is found that, during the adjustment of the silicon-controlled rectifier, the AC mains voltage is almost instantaneously applied to the LC input filter of the LED driving power supply, so that the voltage step applied to the inductor causes oscillation, and due to the frequent switching of the phase angle, the LED driving power supply cannot maintain stable output, and problems such as slight flicker and audio noise are caused. The existing method generally sets an EMI filter circuit in the system to reduce the occurrence of the oscillation, but the EMI filter circuit on the market has the problems of complex structure and inability to accurately detect the phase angle.

[0003] The application aims to provide a silicon-controlled light modulation device of an LED driving power supply which solves at least one of the above problems. SUMMARY

[0004] The application aims to provide a silicon-controlled light modulation device of an LED driving power supply which solves at least one of the above problems.

[0005] The application provides a silicon-controlled light modulation device of an LED driving power supply, which comprises a voltage transformation unit, a rectification filter unit, a first switch unit, a first filter unit, a first voltage stabilization unit, a phase detection module, a control unit and a first voltage terminal. The input end of the voltage transformation unit is electrically connected with a front-stage circuit, the output end of the voltage transformation unit is electrically connected with the rectification filter unit, the first voltage stabilization unit and the phase detection module, the rectification filter unit is electrically connected with the input end of the first filter unit through the first switch unit, the output end of the first filter unit is electrically connected with a light source assembly, the phase detection module and the first switch unit are electrically connected with the control unit, and the rectification filter unit, the first filter unit and the first voltage stabilization unit are electrically connected with the first voltage terminal. The phase detection module comprises a rectification unit, a voltage distribution unit and a second switch unit which are electrically connected in sequence, the input end of the rectification unit is electrically connected with the output end of the voltage transformation unit, the voltage distribution unit is electrically connected with the first voltage stabilization unit, and the second switch unit is electrically connected with the control unit. The front-stage circuit outputs a dimmer wave through phase-cut control after voltage conversion, the reflected voltage of the voltage transformation unit is rectified into a pulse wave by the rectification unit, the pulse wave is divided by the voltage distribution unit to drive the second switch unit, and the pulse wave is converted into a square wave with a duty ratio, the control unit outputs a corresponding driving waveform to the first switch unit according to the duty ratio of the square wave, and the first switch unit is driven to perform voltage chopping to realize the change of the output current in the range of 1-100% for dimming.

[0006] As preferred, the second voltage stabilizing unit is further included, and the second voltage stabilizing unit is electrically connected with the control unit and the first voltage terminal respectively.

[0007] As preferred, the current collecting unit and the overcurrent protection unit are further included, the current collecting unit is arranged between the rectification filter unit and the first switch unit, and the overcurrent protection unit is electrically connected with the first switch unit, the control unit and the second voltage stabilizing unit respectively.

[0008] As preferred, the anti-reverse connection unit is further included, and the anti-reverse connection unit is connected in parallel to both ends of the input terminal of the first filter unit.

[0009] As preferred, the rectification filter unit includes a first diode, a first resistor, a first capacitor, a second capacitor, a third capacitor and a fourth capacitor, the first switch unit includes a second resistor and a first switch tube, the first filter unit includes a first inductor, and the current collecting unit includes a sampling resistor. The first resistor and the first capacitor are connected in series and then connected in parallel to both ends of the first diode, the positive electrode of the first diode is electrically connected with the first terminal of the output terminal of the voltage transformation unit, the second capacitor, the third capacitor and the fourth capacitor are connected in parallel to each other between the negative electrode of the first diode and the second terminal of the output terminal of the voltage transformation unit, the second terminal of the output terminal of the voltage transformation unit is electrically connected with the first grounding terminal, and the negative electrode of the first diode is electrically connected with the first voltage terminal. The first terminal of the sampling resistor is electrically connected with the first grounding terminal and one end of the fourth capacitor respectively, the second terminal of the sampling resistor is electrically connected with the second grounding terminal and the first terminal of the first switch tube respectively, the control terminal of the first switch tube is electrically connected with the control unit, the second resistor is connected in series between the control terminal of the first switch tube and the first terminal of the first switch tube, the second terminal of the first switch tube and the first voltage terminal are connected with the input terminal of the first inductor respectively, and the output terminal of the first inductor is electrically connected with the light source assembly.

[0010] As preferred, the first voltage stabilizing unit includes a second diode, a third diode, a three-terminal voltage stabilizing tube, an optocoupler, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a fifth capacitor, a sixth capacitor, a seventh capacitor and an eighth capacitor. The positive pole of the second diode is electrically connected with the first end of the output end of the voltage transformation unit, the eighth capacitor and the third resistor are connected in parallel between the negative pole of the second diode and the first ground end, the third diode and the three-terminal voltage stabilizing tube are connected in series between the negative pole of the second diode and the first ground end, the fourth resistor and the optocoupler are connected in series between the negative pole of the second diode and the negative pole of the three-terminal voltage stabilizing tube, the sixth resistor, the seventh resistor and the eighth resistor are connected in series between the first voltage end and the first ground end, the fifth resistor and the fifth capacitor are connected in series between the control end of the three-terminal voltage stabilizing tube and the negative pole of the three-terminal voltage stabilizing tube, the two ends of the sixth capacitor are electrically connected with the negative pole of the three-terminal voltage stabilizing tube and the seventh resistor respectively, the control end of the three-terminal voltage stabilizing tube is electrically connected with the connecting point of the seventh resistor and the eighth resistor, and the seventh capacitor is connected in parallel with the two ends of the eighth resistor.

[0011] Preferably, the rectifying unit comprises a fourth diode, the voltage distribution unit comprises a ninth resistor, a tenth resistor and a ninth capacitor, and the second switching unit comprises a second switching tube, a fifth diode, an eleventh resistor and a twelfth resistor.

[0012] The negative pole of the fourth diode is electrically connected with the first end of the output end of the voltage transformation unit and the positive pole of the second diode respectively, the positive pole of the fourth diode is electrically connected with the control unit after being connected with the tenth resistor and the twelfth resistor in series, the ninth resistor and the ninth capacitor are connected in parallel between the positive pole of the fourth diode and the first ground end, the control end of the second switching tube is electrically connected with the connecting point of the tenth resistor and the twelfth resistor, the fifth diode is connected in series between the control end of the second switching tube and the first ground end, the eleventh resistor is connected in series between the first end of the second switching tube and the control unit, and the second end of the second switching tube is connected with the first ground end.

[0013] Preferably, the second voltage stabilizing unit comprises a first triode, a sixth diode, a thirteenth resistor and a tenth capacitor. The thirteenth resistor is connected in series between the control end of the first triode and the first voltage end, the sixth diode is connected in series between the control end of the first triode and the first ground end, the first end of the first triode is electrically connected with the first voltage end, the tenth capacitor is connected in series between the second end of the first triode and the first ground end, and the second end of the first triode is electrically connected with the control unit.

[0014] Preferably, the overcurrent protection unit comprises a second triode, a third triode, a seventh diode, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, an eleventh capacitor and a twelfth capacitor. The control terminal of the second transistor is connected in series with the eighteenth and seventeenth resistors and electrically connected to the second terminal of the first transistor. The two ends of the eighteenth resistor are connected in series with the seventh diode and the sixteenth resistor. The connection point of the sixteenth resistor and the seventh diode is electrically connected to the second ground terminal. The control terminal and the first terminal of the second transistor are electrically connected to the first terminal and the control terminal of the third transistor, respectively. The control terminal and the second terminal of the second transistor are connected in series with the twelfth capacitor. The second terminal of the second transistor is electrically connected to the first ground terminal. The control terminal and the second terminal of the third transistor are connected in parallel with the eleventh capacitor and the fifteenth resistor. The second terminal of the third transistor is connected in series with the control unit with the fourteenth resistor. The second terminal of the third transistor is electrically connected to the first switching unit.

[0015] This invention provides a thyristor dimming device for an LED driver power supply. Through structural design, the transformer unit isolates mains noise, and the square wave signal generated after rectification and voltage division of the reflected voltage exhibits high stability and strong anti-interference capabilities. A phase detection module, in conjunction with a rectifier and filter unit, filters out noise in the voltage signal, reducing errors and improving phase detection accuracy. A first filter unit, in conjunction with a first switch unit, fills in missing waveform energy, resulting in a smoother output current. The rectification, filtering, phase detection, and voltage regulation control employ a modular design, resulting in high system integration. This allows for compatibility with various LED loads and simplifies the circuit structure. It solves the problem of slight LED flicker caused by output current following input changes in low-cost dimmers and also provides overcurrent protection. Attached Figure Description

[0016] Figure 1 This is a structural principle block diagram of a thyristor dimming device for an LED driver power supply provided by the present invention.

[0017] Figure 2 yes Figure 1 The circuit schematic in the image.

[0018] Figure 3 This is a signal waveform diagram of a thyristor dimming device for an LED driver power supply provided by the present invention.

[0019] Figure 4 This is a schematic diagram of a square wave with a duty cycle of 50% and its corresponding driving waveform provided by the present invention.

[0020] The attached figures are labeled as follows: 1, voltage conversion unit; 2, rectifier filter unit; 3, first switch unit; 4, first filter unit; 5, first voltage stabilization unit; 6, phase detection module; 61, rectifier unit; 62, voltage distribution unit; 63, second switch unit; 7, control unit; 8, second voltage stabilization unit; 9, current collection unit; 10, overcurrent protection unit; 11, reverse connection prevention unit; 100, pre-stage circuit; 200, light source assembly; 300, first voltage terminal; D17, first diode; R36, first resistor; C13, first capacitor; CE5, second capacitor; CE6, third capacitor; CE7, fourth capacitor; R42, second resistor; Q3, first switch tube; LF3, first inductor; R16, sampling resistor; D13, second diode; D14, third diode; U4, three-terminal voltage regulator; U1A, optocoupler; R38, third resistor; R39, fourth resistor; R40, fifth resistor; R47, sixth resistor; R47A, seventh resistor; R48, eighth resistor; C18, fifth capacitor; C29, sixth capacitor; C30, seventh capacitor; CE3, eighth capacitor; D15, fourth diode; R34, ninth resistor; R41, tenth resistor; C11, ninth capacitor; Q2, second switch tube; D11, fifth diode; R35, eleventh resistor; R50, twelfth resistor; Q8, first triode; ZD6, sixth diode; R60, thirteenth resistor; C28, tenth capacitor; Q4, second triode; Q7, third triode; D19, seventh diode; R32, fourteenth resistor; R43, fifteenth resistor; R44, sixteenth resistor; R57, seventeenth resistor; R58, eighteenth resistor; C26, eleventh capacitor; C27, twelfth capacitor; D21, eighth diode; R45, nineteenth resistor; TR1, transformer; U3, control chip; GND, first ground terminal; GND1, second ground terminal. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0022] In the embodiment, as shown in the figure, Figures 1-2As shown, the LED driving power supply thyristor dimming device disclosed by the application comprises a voltage conversion unit 1, a rectification filter unit 2, a first switch unit 3, a first filter unit 4, a first voltage stabilizing unit 5, a phase detection module 6, a control unit 7 and a first voltage terminal 300; the input end of the voltage conversion unit 1 is electrically connected with a front-stage circuit 100, the output end of the voltage conversion unit 1 is electrically connected with the rectification filter unit 2, the first voltage stabilizing unit 5 and the phase detection module 6 respectively, the rectification filter unit 2 is electrically connected with the input end of the first filter unit 4 through the first switch unit 3, the output end of the first filter unit 4 is electrically connected with a light source assembly 200, the phase detection module 6 and the first switch unit 3 are electrically connected with the control unit 7 respectively, and the rectification filter unit 2, the first filter unit 4 and the first voltage stabilizing unit 5 are electrically connected with the first voltage terminal 300 respectively. The first voltage terminal 300 is obtained by AC-DC conversion and voltage reduction of an alternating current.

[0023] The phase detection module 6 comprises a rectification unit 61, a voltage distribution unit 62 and a second switch unit 63 which are electrically connected in sequence; the input end of the rectification unit 61 is electrically connected with the output end of the voltage conversion unit 1, the voltage distribution unit 62 is electrically connected with the first voltage stabilizing unit 5, and the second switch unit 63 is electrically connected with the control unit 7.

[0024] The front-stage circuit 100 converts and outputs a phase-cut controlled steamed-bun wave, the reflected voltage of the voltage conversion unit 1 is rectified into a pulse wave by the rectification unit 61, the pulse wave is divided by the voltage distribution unit 62 to drive the second switch unit 63, the pulse wave is converted into a square wave with a duty ratio, and the control unit 7 outputs a corresponding driving waveform to the first switch unit 3 according to the size of the duty ratio of the square wave, the first switch unit 3 is driven to perform voltage chopping, and the output current is changed in the range of 1-100% to realize dimming.

[0025] The LED driving power supply thyristor dimming device further comprises a second voltage stabilizing unit 8, a current acquisition unit 9, an overcurrent protection unit 10 and an anti-reverse connection unit 11; the second voltage stabilizing unit 8 is electrically connected with the control unit 7 and the first voltage terminal 300 respectively, the current acquisition unit 9 is arranged between the rectification filter unit 2 and the first switch unit 3, the overcurrent protection unit 10 is electrically connected with the first switch unit 3, the control unit 7 and the second voltage stabilizing unit 8 respectively, and the anti-reverse connection unit 11 is connected in parallel to both ends of the input end of the first filter unit 4.

[0026] The first voltage stabilizing unit 5 provides a stable power supply voltage for the control unit 7, the second voltage stabilizing unit 8 outputs a voltage through a transistor linear regulation to suppress voltage fluctuation and provide an independent and stable power supply environment for the internal circuit of the control unit 7, and the two units cooperate to realize voltage stabilization and improve the reliability of the system.

[0027] As shown in the figure, Figure 2As shown, the rectifier filter unit 2 includes a first diode D17, a first resistor R36, a first capacitor C13, a second capacitor CE5, a third capacitor CE6, a fourth capacitor CE7; the first switch unit 3 includes a second resistor R42, a first switch tube Q3; the first filter unit 4 includes a first inductor LF3; the current collection unit 9 includes a sampling resistor R16, and the reverse connection prevention unit 11 includes an eighth diode D21. Wherein, the voltage transformation unit 1 includes a transformer TR1, and the control unit 7 includes a control chip U3.

[0028] The first resistor R36 and the first capacitor C13 are connected in series and then connected in parallel between the two ends of the first diode D17, the positive electrode of the first diode D17 is electrically connected with the first end of the output end of the transformer TR1, the second capacitor CE5, the third capacitor CE6 and the fourth capacitor CE7 are connected in parallel between the negative electrode of the first diode D17 and the second end of the output end of the transformer TR1 in turn, the second end of the output end of the transformer TR1 is electrically connected with the first ground end GND, and the negative electrode of the first diode D17 is electrically connected with the first voltage end 300. The first diode D17 and the multiple-stage capacitors such as the second capacitor CE5, the third capacitor CE6 and the fourth capacitor CE7 form a π-type filter, which can improve the rectification efficiency and reduce the input voltage ripple.

[0029] The first end of the sampling resistor R16 is electrically connected with the first ground end GND and one end of the fourth capacitor CE7 respectively, the second end of the sampling resistor R16 is electrically connected with the second ground end GND1 and the first end of the first switch tube Q3 respectively, the control end of the first switch tube Q3 is electrically connected with the control unit 7, the second resistor R42 is connected in series between the control end and the first end of the first switch tube Q3, the second end of the first switch tube Q3 and the first voltage end 300 are connected with the input end of the first inductor LF3 respectively, and the output end of the first inductor LF3 is electrically connected with the light source assembly 200. The eighth diode D21 is connected in series between the input end of the first inductor LF3, which is used for preventing the electronic components in the circuit from being damaged when the power supply is reversely connected, and can also absorb the reverse electromotive force generated when the freewheeling current exists in the first inductor LF3, so as to avoid the voltage peak from breaking through the first switch tube Q3. Wherein, the first switch tube Q3 is a MOS tube.

[0030] The first voltage stabilization unit 5 includes a second diode D13, a third diode D14, a three-terminal voltage regulator U4, an optocoupler U1A, a third resistor R38, a fourth resistor R39, a fifth resistor R40, a sixth resistor R47, a seventh resistor R47A, an eighth resistor R48, a fifth capacitor C18, a sixth capacitor C29, a seventh capacitor C30, and an eighth capacitor CE3.

[0031] The positive electrode of the second diode D13 is electrically connected with the first end of the transformer TR1 output end, and the negative electrode of the second diode D13 is provided with the eighth capacitor CE3 and the third resistor R38 in parallel between the first ground terminal GND, and the negative electrode of the second diode D13 is further provided with the third diode D14 and the three-terminal voltage regulator U4 in series, and the negative electrode of the three-terminal voltage regulator U4 is sequentially connected with the fourth resistor R39 and the emitting end of the optical coupler U1A between the negative electrode of the second diode D13, and the first voltage terminal 300 is sequentially connected with the sixth resistor R47, the seventh resistor R47A and the eighth resistor R48 between the first ground terminal GND, and the control terminal of the three-terminal voltage regulator U4 is sequentially connected with the fifth resistor R40 and the fifth capacitor C18 between the negative electrode of the three-terminal voltage regulator U4, and the two ends of the sixth capacitor C29 are respectively electrically connected with the negative electrode of the three-terminal voltage regulator U4 and the seventh resistor R47A, and the control terminal of the three-terminal voltage regulator U4 is electrically connected with the connection point of the seventh resistor R47A and the eighth resistor R48, and the seventh capacitor C30 is connected in parallel with the two ends of the eighth resistor R48.

[0032] The receiving end of the optical coupler U1A is connected with the front-stage circuit 100, and the voltage feedback is realized by the three-terminal voltage regulator U4 cooperating with the optical coupler U1A, the voltage of the input end of the transformer unit 1 is adjusted by the front-stage circuit 100, the output voltage fluctuation is suppressed, the accuracy of the phase detection is ensured, and the high-voltage side and the low-voltage side of the transformer unit 1 are isolated by the optical coupler U1A, the isolation protection is realized, the fifth capacitor C18 and the fifth resistor R40 constitute a phase compensation network, and the voltage stabilizing loop oscillation is avoided.

[0033] The rectifier unit 61 includes the fourth diode D15, the voltage distribution unit 62 includes the ninth resistor R34, the tenth resistor R41 and the ninth capacitor C11, and the second switch unit 63 includes the second switch tube Q2, the fifth diode D11, the eleventh resistor R35 and the twelfth resistor R50.

[0034] The negative electrode of the fourth diode D15 is respectively electrically connected with the first end of the transformer TR1 output end and the positive electrode of the second diode D13, the positive electrode of the fourth diode D15 is electrically connected with the control unit 7 after sequentially connecting the tenth resistor R41 and the twelfth resistor R50, the ninth resistor R34 and the ninth capacitor C11 are connected in parallel between the positive electrode of the fourth diode D15 and the first ground terminal GND, the control terminal of the second switch tube Q2 is electrically connected with the connection point of the tenth resistor R41 and the twelfth resistor R50, the fifth diode D11 is connected in series between the control terminal of the second switch tube Q2 and the first ground terminal GND, the eleventh resistor R35 is connected in series between the first end of the second switch tube Q2 and the control unit 7, and the second end of the second switch tube Q2 is connected with the first ground terminal GND. Among them, the tenth resistor R41 is a pull-up resistor, the ninth resistor R34 is a pull-down resistor, and the second switch tube Q2 is a MOS tube.

[0035] The voltage distribution unit 62 can be adapted to different transformer output voltages, ensuring that the voltage signal amplitude matches the input level of the control unit 7. The ninth capacitor C11 filters high-frequency noise and reduces the zero-crossing detection error of the second switch Q2.

[0036] The second voltage regulator unit 8 includes a first transistor Q8, a sixth diode ZD6, a thirteenth resistor R60, and a tenth capacitor C28. The thirteenth resistor R60 is connected in series between the control terminal of the first transistor Q8 and the first voltage terminal 300. The sixth diode ZD6 is connected in series between the control terminal of the first transistor Q8 and the first ground terminal GND. The first terminal of the first transistor Q8 is electrically connected to the first voltage terminal 300. The tenth capacitor C28 is connected in series between the second terminal of the first transistor Q8 and the first ground terminal GND. The second terminal of the first transistor Q8 is electrically connected to the control unit 7. The second terminal of the first transistor Q8 is also electrically connected to the control unit 7 through a nineteenth resistor R45. The first transistor Q8 and the sixth diode ZD6 form a linear voltage regulator. Connecting the enable terminal of the control unit 7 through the nineteenth resistor R45 allows for remote shutdown of the first transistor Q8.

[0037] like Figure 3 As shown, when the conduction angle of the thyristor dimmer is adjusted, the AC sine wave A1 is rectified by the rectifier bridge and converted into a dome wave (waveform A2). This dome wave is then phase-cut modulated and converted into a phase-cut dome wave (waveform A3). The phase-cut dome wave A3 is then rectified by the fourth diode D15 and converted into a pulse wave (waveform A4). Finally, after driving the second switch Q2 to conduct, a square wave with a duty cycle is output (waveform A5). The duty cycle of the square wave is related to the phase angle; the larger the phase angle, the smaller the duty cycle. The specific amplitude of the square wave is determined by the control voltage of the control unit 7. Therefore, the phase angle can be determined based on the duty cycle of the square wave. The control unit 7 outputs a drive waveform based on the square wave. Figure 4 The corresponding waveform is a square wave with a duty cycle of 50% and its corresponding driving waveform.

[0038] like Figure 2As shown, the reflected voltage of the transformer TR1 is rectified by the fourth diode D15, the tenth resistor R41 and the ninth resistor R34 in the voltage distribution unit 62 are used for voltage division to drive the second switch tube Q2, which is used for determining the high and low level information at the DIM port of the control chip U3. Since the voltage rectified by the fourth diode D15 is delayed by the first capacitor C13, the noise is filtered out, and the voltage rectified by the fourth diode D15 is a pulse waveform, so the conduction waveform of the second switch tube Q2 is a square wave with a duty cycle. The high and low level information at the DIM port of the control chip U3 is identified by adjusting the size of the pulse waveform duty cycle. The control chip U3 obtains a square wave with a duty cycle through internal calculation, and outputs a corresponding driving waveform to the first switch tube Q3 according to the size of the square wave duty cycle. The fourteenth resistor R32 chops the voltage to drive the conduction of the first switch tube Q3, so as to realize the change of the output current in the range of 1-100% for dimming.

[0039] The overcurrent protection unit 10 includes a second transistor Q4, a third transistor Q7, a seventh diode D19, a fourteenth resistor R32, a fifteenth resistor R43, a sixteenth resistor R44, a seventeenth resistor R57, an eighteenth resistor R58, an eleventh capacitor C26, and a twelfth capacitor C27. The control end of the second transistor Q4 is connected with the second end of the first transistor Q8 in series through the eighteenth resistor R58 and the seventeenth resistor R57. The two ends of the eighteenth resistor R58 are connected with the second ground terminal GND1 in series through the seventh diode D19 and the sixteenth resistor R44. The connection point of the sixteenth resistor R44 and the seventh diode D19 is connected with the second ground terminal GND1. The control end and the first end of the second transistor Q4 are connected with the first end of the third transistor Q7 and the control end of the third transistor Q7 respectively. The twelfth capacitor C27 is connected between the control end and the second end of the second transistor Q4. The second end of the second transistor Q4 is connected with the first ground terminal GND. The control end and the second end of the third transistor Q7 are provided with the eleventh capacitor C26 and the fifteenth resistor R43 connected in parallel. The second end of the third transistor Q7 is connected with the control unit 7 in series through the fourteenth resistor R32. The second end of the third transistor Q7 is connected with the control end of the first switch tube Q3 in the first switch unit 3.

[0040] The output current of the triac dimming device is detected in real time by the sampling resistor R16. The voltage drop across the sampling resistor R16 provides a voltage difference to the B electrode of the second transistor Q4. When the voltage difference between the B-E electrodes of the second transistor Q4 is greater than 0.7V, the C-E electrodes of the second transistor Q4 are turned on, the driving waveform is pulled down through the fifteenth resistor R43, the PWM waveform is turned off, the first switch tube Q3 is turned off, the overcurrent protection is realized, and the system can automatically recover after the overcurrent protection is removed. Under normal circumstances, manual intervention is not required.

[0041] The present application is not limited to the above best mode, anyone under the inspiration of the present application can derive other various forms of products, but regardless of any changes in its shape or structure, as long as it has the same or similar technical solutions as this application, it falls within the scope of the present application.

Claims

1. A thyristor dimming device for an LED driver power supply, characterized in that: It includes a transformer unit (1), a rectifier and filter unit (2), a first switch unit (3), a first filter unit (4), a first voltage regulator unit (5), a phase detection module (6), a control unit (7), and a first voltage terminal (300); The input terminal of the transformer unit (1) is electrically connected to the pre-amplifier circuit (100). The output terminal of the transformer unit (1) is electrically connected to the rectifier filter unit (2), the first voltage regulator unit (5), and the phase detection module (6), respectively. The rectifier filter unit (2) is electrically connected to the input terminal of the first filter unit (4) through the first switch unit (3). The output terminal of the first filter unit (4) is electrically connected to the light source assembly (200). The phase detection module (6) and the first switch unit (3) are electrically connected to the control unit (7), respectively. The rectifier filter unit (2), the first filter unit (4), and the first voltage regulator unit (5) are electrically connected to the first voltage terminal (300), respectively. The phase detection module (6) includes a rectifier unit (61), a voltage distribution unit (62), and a second switch unit (63) connected in sequence. The input terminal of the rectifier unit (61) is electrically connected to the output terminal of the transformer unit (1), the voltage distribution unit (62) is electrically connected to the first voltage regulator unit (5), and the second switch unit (63) is electrically connected to the control unit (7). The pre-amplifier circuit (100) performs voltage conversion and outputs a phase-cutting controlled swivel wave. The reflected voltage of the transformer unit (1) is rectified into a pulse wave by the rectifier unit (61). The pulse wave is divided by the voltage distribution unit (62) to drive the second switching unit (63) and convert the pulse wave into a square wave with a duty cycle. The control unit (7) outputs the corresponding driving waveform to the first switching unit (3) according to the size of the duty cycle of the square wave. The first switching unit (3) is driven to perform voltage chopping to realize the dimming of the output current within the range of 1-100%.

2. The thyristor dimming device for LED driver power supply as described in claim 1, characterized in that: It also includes a second voltage regulator unit (8), which is electrically connected to the control unit (7) and the first voltage terminal (300) respectively.

3. The thyristor dimming device for LED driver power supply as described in claim 2, characterized in that: It also includes a current acquisition unit (9) and an overcurrent protection unit (10). The current acquisition unit (9) is located between the rectifier filter unit (2) and the first switch unit (3). The overcurrent protection unit (10) is electrically connected to the first switch unit (3), the control unit (7) and the second voltage regulator unit (8) respectively.

4. The thyristor dimming device for LED driver power supply as described in claim 1, characterized in that: It also includes a reverse connection protection unit (11), which is connected in parallel to both ends of the input terminal of the first filter unit (4).

5. The thyristor dimming device for LED driver power supply as described in claim 3, characterized in that: The rectifier filter unit (2) includes a first diode (D17), a first resistor (R36), a first capacitor (C13), a second capacitor (CE5), a third capacitor (CE6), and a fourth capacitor (CE7); the first switch unit (3) includes a second resistor (R42) and a first switch transistor (Q3); the first filter unit (4) includes a first inductor (LF3); and the current acquisition unit (9) includes a sampling resistor (R16). The first resistor (R36) and the first capacitor (C13) are connected in series and then connected in parallel across the first diode (D17). The positive terminal of the first diode (D17) is electrically connected to the first terminal of the output of the transformer unit (1). The negative terminal of the first diode (D17) is connected in parallel with the second terminal of the output of the transformer unit (1) in sequence, followed by the second capacitor (CE5), the third capacitor (CE6), and the fourth capacitor (CE7). The second terminal of the output of the transformer unit (1) is electrically connected to the first ground terminal (GND), and the negative terminal of the first diode (D17) is electrically connected to the first voltage terminal (300). The first end of the sampling resistor (R16) is electrically connected to the first ground terminal (GND) and one end of the fourth capacitor (CE7), respectively. The second end of the sampling resistor (R16) is electrically connected to the second ground terminal (GND1) and the first end of the first switch (Q3), respectively. The control terminal of the first switch (Q3) is electrically connected to the control unit (7). A second resistor (R42) is connected in series between the control terminal of the first switch (Q3) and its first end. The second end and the first voltage terminal (300) of the first switch (Q3) are respectively connected to the input terminal of the first inductor (LF3), and the output terminal of the first inductor (LF3) is electrically connected to the light source assembly (200).

6. The thyristor dimming device for an LED driver power supply as described in any one of claims 1-5, characterized in that: The first voltage regulator unit (5) includes a second diode (D13), a third diode (D14), a three-terminal Zener diode (U4), an optocoupler (U1A), a third resistor (R38), a fourth resistor (R39), a fifth resistor (R40), a sixth resistor (R47), a seventh resistor (R47A), an eighth resistor (R48), a fifth capacitor (C18), a sixth capacitor (C29), a seventh capacitor (C30), and an eighth capacitor (CE3). The positive terminal of the second diode (D13) is electrically connected to the first terminal of the output of the transformer unit (1). An eighth capacitor (CE3) and a third resistor (R38) are connected in parallel between the negative terminal of the second diode (D13) and the first ground terminal (GND). A third diode (D14) and a three-terminal Zener diode (U4) are also connected in series between the negative terminal of the second diode (D13) and the first ground terminal (GND). A fourth resistor (R39) and an optocoupler (U1A) are connected in series between the negative terminal of the second diode (D13) and the negative terminal of the three-terminal Zener diode (U4). The first voltage terminal (300) and the... A sixth resistor (R47), a seventh resistor (R47A), and an eighth resistor (R48) are connected in series between a ground terminal (GND). A fifth resistor (R40) and a fifth capacitor (C18) are connected in series between the control terminal of the three-terminal Zener diode (U4) and its negative terminal. The two ends of the sixth capacitor (C29) are electrically connected to the negative terminal of the three-terminal Zener diode (U4) and the seventh resistor (R47A), respectively. The control terminal of the three-terminal Zener diode (U4) is electrically connected to the connection point of the seventh resistor (R47A) and the eighth resistor (R48). The seventh capacitor (C30) is connected in parallel across the eight resistors (R48).

7. The thyristor dimming device for LED driver power supply as described in claim 6, characterized in that: The rectifier unit (61) includes a fourth diode (D15), the voltage distribution unit (62) includes a ninth resistor (R34), a tenth resistor (R41), and a ninth capacitor (C11), and the second switching unit (63) includes a second switching transistor (Q2), a fifth diode (D11), an eleventh resistor (R35), and a twelfth resistor (R50). The negative terminal of the fourth diode (D15) is electrically connected to the first terminal of the output terminal of the transformer unit (1) and the positive terminal of the second diode (D13). The positive terminal of the fourth diode (D15) is connected in series with the tenth resistor (R41) and the twelfth resistor (R50) and then electrically connected to the control unit (7). A ninth resistor (R34) and a ninth capacitor (C11) are connected in parallel between the positive terminal of the fourth diode (D15) and the first ground terminal (GND). The control terminal of the second switch (Q2) is electrically connected to the connection point of the tenth resistor (R41) and the twelfth resistor (R50). A fifth diode (D11) is connected in series between the control terminal of the second switch (Q2) and the first ground terminal (GND). An eleventh resistor (R35) is connected in series between the first terminal of the second switch (Q2) and the control unit (7). The second terminal of the second switch (Q2) is connected to the first ground terminal (GND).

8. The thyristor dimming device for an LED driver power supply as described in claim 3 or 5, characterized in that: The second voltage regulator unit (8) includes a first transistor (Q8), a sixth diode (ZD6), a thirteenth resistor (R60), and a tenth capacitor (C28); A thirteenth resistor (R60) is connected in series between the control terminal of the first transistor (Q8) and the first voltage terminal (300). A sixth diode (ZD6) is connected in series between the control terminal of the first transistor (Q8) and the first ground terminal (GND). The first terminal of the first transistor (Q8) is electrically connected to the first voltage terminal (300). A tenth capacitor (C28) is connected in series between the second terminal of the first transistor (Q8) and the first ground terminal (GND). The second terminal of the first transistor (Q8) is electrically connected to the control unit (7).

9. The thyristor dimming device for an LED driver power supply as described in claim 8, characterized in that: The overcurrent protection unit (10) includes a second transistor (Q4), a third transistor (Q7), a seventh diode (D19), a fourteenth resistor (R32), a fifteenth resistor (R43), a sixteenth resistor (R44), a seventeenth resistor (R57), an eighteenth resistor (R58), an eleventh capacitor (C26), and a twelfth capacitor (C27). The control terminal of the second transistor (Q4) is connected in series with the eighteenth resistor (R58) and the seventeenth resistor (R57), and is electrically connected to the second terminal of the first transistor (Q8). The two ends of the eighteenth resistor (R58) are connected in series with the seventh diode (D19) and the sixteenth resistor (R44). The connection point of the sixteenth resistor (R44) and the seventh diode (D19) is electrically connected to the second ground terminal (GND1). The control terminal and the first terminal of the second transistor (Q4) are respectively connected to the first terminal of the third transistor (Q7) and the third transistor (Q7). The control terminal is electrically connected, and the control terminal of the second transistor (Q4) is connected in series with the second terminal with the twelfth capacitor (C27). The second terminal of the second transistor (Q4) is electrically connected with the first ground terminal (GND). The control terminal of the third transistor (Q7) is connected in parallel with the second terminal with the eleventh capacitor (C26) and the fifteenth resistor (R43). The second terminal of the third transistor (Q7) is connected in series with the control unit (7) with the fourteenth resistor (R32). The second terminal of the third transistor (Q7) is electrically connected with the first switching unit (3).

Images