A high-power dimmer

Abstract

This invention discloses a high-power dimmer, comprising a zero-crossing signal detection circuit, a PWM control circuit, a MOS drive circuit, and a MOS switching circuit. The zero-crossing signal detection circuit includes a voltage divider module, a shaping module, and a positive feedback module. The voltage divider module divides the AC input voltage to obtain a voltage at the voltage divider point. This voltage at the voltage divider point is then passed through the parallel shaping module and the positive feedback module to obtain the output voltage at the output terminal of the zero-crossing signal detection circuit. The output terminal of the zero-crossing signal detection circuit is connected to the PWM control circuit, which determines the positive pulse width duration based on the output voltage. The PWM control circuit is also connected to the MOS drive circuit to turn the MOS switching circuit on and off. This high-power dimmer can adjust the brightness by controlling the duration of the PWM positive pulse width, thereby regulating the load's power input. Furthermore, it features low power loss, high output impedance, strong load capacity, and no flickering during dimming.

Description

Technical Field

[0001] This invention relates to the field of dimmer technology, and in particular to a high-power dimmer. Background Technology

[0002] The purpose of a dimmer is to adjust the brightness of lights, providing users with a better lighting environment and experience compared to a regular switch, and therefore it is widely used in daily life. Existing dimming technologies mainly include SCR dimming, linear dimming, and PWM dimming. SCR dimming can only operate under a single input voltage and is difficult to achieve a high power factor; while linear dimming mainly uses a constant current chip's dedicated dimming pin to adjust the current to achieve dimming, and its wiring is relatively complex.

[0003] Compared to the previous two dimming technologies, PWM dimming theoretically offers extremely high dimming accuracy and can achieve better dimming effects. However, the dimmers in these technologies have a small adjustment range, and when using dimmers to dim loads, they may exhibit weak load adaptability and flickering, leading to the load being unable to function properly. Summary of the Invention

[0004] This application addresses the aforementioned problems and technical needs by proposing a high-power dimmer. The technical solution of this invention is as follows:

[0005] A high-power dimmer includes a zero-crossing signal detection circuit, a PWM control circuit, a MOS drive circuit, and a MOS switching circuit. The zero-crossing signal detection circuit includes a voltage divider module, a shaping module, and a positive feedback module. The voltage divider module divides the AC input voltage to obtain a voltage at the voltage divider point. The shaping module and the positive feedback module are connected in parallel between the voltage divider point and the output terminal of the zero-crossing signal detection circuit. The voltage at the voltage divider point, after passing through the shaping module and the positive feedback module, becomes the output voltage at the output terminal of the zero-crossing signal detection circuit. The output terminal of the zero-crossing signal detection circuit is connected to the PWM control circuit, which determines the positive pulse width duration based on the output voltage. The PWM control circuit is connected to the MOS drive circuit, and the output terminal of the MOS drive circuit is connected to the MOS switching circuit to turn the MOS switching circuit on and off.

[0006] The further technical solution is as follows: The voltage divider module includes resistors R120, R117, R113, and R231 connected in series; one end of resistor R120 is connected to the AC input voltage, and the other end is connected to resistor R117; one end of resistor R231 is connected to resistor R113, and the other end is grounded; the positive feedback module includes transistors U213A, U213B, and Q204; the collector of transistor U213A is connected to the voltage divider point, and the base is connected to the emitter of transistor Q204; both the base and collector of U213B are connected to the base of transistor U213A; the base of transistor Q204 is connected to the output terminal of the zero-crossing signal detection circuit; the shaping module includes transistors U211B, U211A, U202B, U202A, and U210A connected in series, and the collector of transistor U211B is connected to the emitter of transistor Q204. The base of transistor U211A is connected to the base of transistor U202B, the emitter of transistor U202B is connected to the base of transistor U202A, and the collector of transistor U202A is connected to the base of transistor U210A. The collector of transistor U210A is connected to the output of the zero-crossing signal detection circuit. The base of transistor U211B is connected to one end of resistor R231. The AC input voltage is divided by the voltage divider module, and the voltage at the dividing point is obtained at one end of resistor R231. The voltage at the dividing point turns on transistor U211B, and the output voltage is obtained at the output of the zero-crossing signal detection circuit through the shaping of transistors U211A, U202B, U202A, and U210A, as well as the positive feedback of transistors Q204, U213A, and U213B.

[0007] A further technical solution is as follows: the PWM control circuit includes a potentiometer VR1, a capacitor C214, and transistors U204A, U212A, U209A, U209B, U207A, U207B, and Q203; the emitter of transistor U204A is connected to the base of transistor U209B via resistor R224; the base of transistor U209A and the emitter of transistor U209B are connected to the power supply voltage via resistor R225; the emitter of transistor U209A is connected to potentiometer VR1, and the collector is connected to the power supply voltage; transistor U209B... The collector of transistor U207A is grounded; the base of transistor U212A is connected to the output of the zero-crossing signal detection circuit, and its collector is connected to the base of transistor U207B; the emitter of transistor U207B is connected via resistor R220, and its collector is connected to one end of capacitor C214, with the other end of capacitor C214 grounded; the emitter of transistor U207A is connected to the collector of transistor U207B, its base is connected to potentiometer VR1, and its collector is connected to the base of transistor Q203; the collector of transistor Q203 is connected to the MOS drive circuit via resistor R218.

[0008] A further technical solution is as follows: the MOS driving circuit includes transistors U215A, U215B, and Q205 forming a half-bridge drive, and resistors R241, R243, and R242; the base of transistor Q205 is connected to the PWM control circuit; the bases of transistors U215A and U215B are both connected to the emitter of transistor Q205; the emitter of transistor U215A is connected to the emitter of transistor U215B via resistors R243 and R242 in series; the collector of transistor U215A is connected to the power supply voltage, and the collectors of transistors Q205 and U215B are both grounded; one end of resistor R241 is connected to the power supply voltage, and the other end is connected to the base of transistors U215A and U215B and the emitter of transistor Q205.

[0009] A further technical solution is that the MOS switching circuit includes MOS switches Q300 and Q301. The gate of MOS switch Q300 is connected to the output terminal of the MOS driving circuit via resistor R300, and the gate of MOS switch Q301 is connected to the output terminal of the MOS driving circuit via resistor R301. The drains of MOS switches Q300 and Q301 are connected to the live wire terminals L1 and L2, respectively. The sources of MOS switches Q300 and Q301 are both grounded.

[0010] A further technical solution is that the dimmer also includes an anti-flicker circuit, which includes a PWM positive pulse rising edge lock-in circuit and a PWM negative pulse falling edge lock-in circuit. The PWM positive pulse rising edge lock-in circuit includes transistors Q109 and U106A. The base of transistor Q109 is connected to the base of transistor U215A in the MOS driver circuit via resistor R135 and transistor U218A. The emitter of transistor Q109 is connected to the base of transistor U106A via capacitor C109. The collector of transistor U106A is connected to the voltage divider module. Both the collector of transistor Q109 and the emitter of transistor U106A are connected to the power supply voltage. The PWM negative pulse falling edge lock-in circuit includes transistors Q101 and U106A. 2A, U102B, U101B, the bases of transistors U102A and U102B are connected to the base of transistor U215A in the MOS driver circuit via transistor U218A. The emitter of transistor U102A is connected to the emitter of transistor U102B. The collector of transistor U102A is connected to the power supply voltage, and the collector of transistor U102B is grounded. The collector of transistor Q101 is connected to the bases of transistors U102A and U102B respectively. The base of transistor Q101 is connected to the collector of transistor U101B. The base of transistor U101B is connected to the emitter of transistor U102A via resistor R105. The emitter of transistor U101B is connected to the PWM control circuit via resistor R107.

[0011] A further technical solution is that the dimmer also includes a protection unit, which includes a load overvoltage protection circuit and a lightning strike protection circuit; the load overvoltage protection circuit includes a transistor Q108, and the lightning strike protection circuit includes transistors U103A and U103B; the AC input voltage is connected to the base of transistor Q108 via a diode D105, a varistor RV100, a resistor R139, and a resistor R125 connected in series; the collector of transistor Q108 is connected to the PWM control circuit, and the emitter is grounded; resistor R125 is connected to resistor R139. One end is connected to one end of resistor R124, and the other end of resistor R124 is grounded; the end of resistor R139 connected to varistor RV100 is connected to the emitter of transistor U103A, and the end of resistor R139 connected to resistor R125 is connected to the base of transistor U103A via resistor R123; the collector of transistor U103A is connected to the collector of transistor U103B; the emitter of transistor U103A is connected to DC power supply via diode D103; the base and emitter of transistor U103B are connected to MOS switching circuit.

[0012] A further technical solution is that the dimmer also includes a low-power power supply circuit, which includes a capacitor C108 and transistors Q102, Q105, Q106, Q107, and U203B. The collector of transistor Q102 is connected to the collector of transistor Q107 via resistors LD103, LD100, and R140 connected in series. The emitter of transistor Q102 is connected to the power supply voltage via resistor R101. The base of transistor Q102 is connected to the collector of transistor Q105 via resistor R114. The emitter of transistor Q105 is connected to the base of transistor Q106. The base of transistor Q105 is connected to the collector of transistor Q106; the emitter of transistor Q106 is connected to the base of transistor Q107; the base of transistor Q106 is connected to the base of transistor Q107 via resistor R121; the emitter of transistor Q107 is connected to the DC power supply via resistor R122; the base of transistor U203B is connected to the power supply voltage via resistor R210; the emitter of transistor U203B is grounded via diode D201; the collector of transistor U203B is connected to the base of transistor Q102 via resistor R213; one end of capacitor C108 is connected to the power supply voltage, and the other end is grounded.

[0013] The beneficial technical effects of this invention are:

[0014] The high-power dimmer disclosed in this invention can adjust the brightness by controlling the duration of the PWM positive pulse width, thereby regulating the power received by the load. Furthermore, this high-power dimmer has low self-loss, high output impedance, strong load capacity, and the load will not flicker during the dimming process. Attached Figure Description

[0015] Figure 1 This is a block diagram of the high-power dimmer of the present invention.

[0016] Figure 2 This is a circuit diagram of the zero-crossing signal detection circuit of the high-power dimmer of the present invention.

[0017] Figure 3 This is a PWM control circuit diagram of the high-power dimmer of the present invention.

[0018] Figure 4 This is a MOS drive circuit diagram of the high-power dimmer of the present invention.

[0019] Figure 5 This is a MOS switch circuit diagram of the high-power dimmer of the present invention.

[0020] Figure 6 This is the anti-flicker circuit diagram of the high-power dimmer of the present invention.

[0021] Figure 7 This is a protection circuit diagram for the high-power dimmer of the present invention.

[0022] Figure 8 This is a low-power power supply circuit diagram for the high-power dimmer of the present invention.

[0023] Marked in the image:

[0024] M1: MOS switching circuit; M2: Zero-crossing signal detection circuit; M3: PWM control circuit; M4: PWM positive pulse rising edge lock-in circuit; M5: PWM negative pulse falling edge lock-in circuit; M6: MOS drive circuit; M7: Overvoltage protection circuit; M8: Lightning protection circuit; M9: Low-power power supply circuit. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0026] In one embodiment, a high-power dimmer is provided, such as Figure 1As shown, it mainly includes a zero-crossing signal detection circuit M2, a PWM control circuit M3, a MOS drive circuit M6, and a MOS switch circuit M1. The zero-crossing signal detection circuit M2 includes a voltage divider module, a shaping module, and a positive feedback module. The voltage divider module divides the AC input voltage to obtain the voltage at the voltage divider point. The shaping module and the positive feedback module are connected in parallel between the voltage divider point and the output terminal of the zero-crossing signal detection circuit M2. The voltage at the voltage divider point is then processed by the shaping module and the positive feedback module to obtain the output voltage at the output terminal of the zero-crossing signal detection circuit M2. The output terminal of the zero-crossing signal detection circuit M2 is connected to the PWM control circuit M3. The PWM control circuit M3 determines the positive pulse width duration based on the output voltage. The PWM control circuit M3 is connected to the MOS drive circuit M6. The output terminal of the MOS drive circuit M6 is connected to the MOS switch circuit M1 to turn the MOS switch circuit on and off.

[0027] Optional, such as Figure 2 As shown, the voltage divider module of the zero-crossing signal detection circuit M2 includes resistors R120, R117, R113, and R231 connected in series. One end of resistor R120 is connected to the AC input voltage Vin+, and the other end is connected to resistor R117. One end of resistor R231 is connected to resistor R113, and the other end is grounded. The positive feedback module of the zero-crossing signal detection circuit M2 includes transistors U213A, U213B, and Q204. The collector of transistor U213A is connected to the voltage divider point A, and its base is connected to the emitter of transistor Q204. The base and collector of U213B are both connected to the base of transistor U213A. The base of transistor Q204 is connected to the output terminal B of the zero-crossing signal detection circuit. The shaping module of the zero-crossing signal detection circuit M2 includes transistors U211B, U211A, U202B, U202A, and U210A connected in sequence. The collector of transistor U211B is connected to the base of transistor U211A, the collector of transistor U211A is connected to the base of transistor U202B, the emitter of transistor U202B is connected to the base of transistor U202A, and the collector of transistor U202A is connected to the base of transistor U210A; the collector of transistor U210A is connected to... The output terminal B of the zero-crossing signal detection circuit is connected; the base of transistor U211B is connected to one end of resistor R231. The AC input voltage Vin+ is divided by the voltage divider module and a voltage divider point voltage is obtained at the voltage divider point A at one end of resistor R231. The voltage divider point voltage turns on transistor U211B, and the output voltage is obtained at the output terminal B of the zero-crossing signal detection circuit through the shaping of transistors U211A, U202B, U202A, and U210A and the positive feedback of transistors Q204, U213A, and U213B.

[0028] Optional, such as Figure 3As shown, the PWM control circuit M3 includes a potentiometer VR1, a capacitor C214, and transistors U204A, U212A, U209A, U209B, U207A, U207B, and Q203. The emitter of transistor U204A is connected to the base of transistor U209B via resistor R224. The base of transistor U209A and the emitter of transistor U209B are connected to the power supply voltage VCC via resistor R225. The emitter of transistor U209A is connected to potentiometer VR1, and the collector is connected to the power supply voltage VCC. The collector of transistor U209B is grounded. The base of transistor U212A is connected to the output terminal B of the zero-crossing signal detection circuit, and its collector is connected to the base of transistor U207B. The emitter of transistor U207B is connected via resistor R220, and its collector is connected to one end of capacitor C214, with the other end of capacitor C214 grounded. The emitter of transistor U207A is connected to the collector of transistor U207B, its base is connected to potentiometer VR1, and its collector is connected to the base of transistor Q203. The collector of transistor Q203 is connected via resistor R218 to the base of transistor Q205 in MOS driver circuit M6.

[0029] Optional, such as Figure 4 As shown, the MOS driver circuit M6 includes transistors U215A, U215B, and Q205 forming a half-bridge driver, and resistors R241, R243, and R242. The base of transistor Q205 is connected to the PWM control circuit. The bases of transistors U215A and U215B are both connected to the emitter of transistor Q205. The emitter of transistor U215A is connected to the emitter of transistor U215B via resistors R243 and R242 in series. The collector of transistor U215A is connected to the power supply voltage VCC, and the collectors of transistors Q205 and U215B are both grounded. One end of resistor R241 is connected to the power supply voltage VCC, and the other end is connected to the base of transistors U215A and U215B and the emitter of transistor Q205.

[0030] Optional, such as Figure 5 As shown, the MOS switch circuit M1 includes MOS switches Q300 and Q301. The gate of MOS switch Q300 is connected to the output terminal of MOS drive circuit M6 via resistor R300, and the gate of MOS switch Q301 is connected to the output terminal of MOS drive circuit M6 via resistor R301. The drains of MOS switches Q300 and Q301 are connected to the live wire terminals L1 and L2, respectively. The sources of MOS switches Q300 and Q301 are both grounded.

[0031] Specifically, the working principles of the zero-crossing signal detection circuit M2, PWM control circuit M3, MOS drive circuit M6, and MOS switching circuit M1 of the high-power dimmer in this embodiment are as follows:

[0032] The MOS switching circuit M1 consists of two MOS switches, Q300 and Q301, connected in series on the input live wire. When both MOS switches are on, it is equivalent to the switch being turned on; when both MOS switches are off, it is equivalent to the switch being turned off. The zero-crossing signal detection circuit M2 and the PWM control circuit M3 can accurately control the two MOS switches to turn on at the AC voltage "zero-crossing point" t0 (at phase 0 degrees, 180 degrees, and 360 degrees) and turn off at t1.

[0033] At time t0, the voltage at the Vin+ node is 0 when the AC voltage "crosses zero". The zero-crossing signal detection circuit M2 divides the voltage through resistors R120, R117, R113 and R231. The voltage at the voltage division point A drops, causing transistor U211B to conduct. Through the shaping of transistors U211A, U202B, U202A, and U210A and the positive feedback of Q204 and U213, the output terminal B of the zero-crossing signal detection circuit M2 receives a positive voltage. At this time, the PWM control circuit M3 transmits the starting control voltage at time t0 generated by this positive voltage to the MOS switching circuit M1 through the MOS drive circuit M6, causing the MOS switch to conduct.

[0034] After receiving a positive voltage at output terminal B of the zero-crossing signal detection circuit M2 at time t0, transistors U212A and U207B in the PWM control circuit M3 turn on. Capacitor C214 begins charging through resistor R220 until time t1. The voltage across capacitor C214 rises from 0V to a point higher than the voltage selected by potentiometer VR1, at which point transistor U207 turns on, causing transistor Q203 to turn on as well. The voltage then drops to 0V at node C through transistor Q205 in the MOS drive circuit M6. At this point, transistor U215B turns on, and U215A turns off, turning off MOS switches Q300 and Q301 in the MOS switching circuit M1. This completes a positive pulse width from time t0 to t1, until the next AC voltage "zero-crossing" occurs, marking the start of the next positive pulse width cycle. This forms the periodic switching of the PWM control circuit.

[0035] By controlling the duration of time t0-t1, the power received by the load can be adjusted, thereby regulating the brightness. During t0-t2, a complete PWM cycle of the MOS switch is formed, with the frequency of the MOS switch being twice that of the AC input. During t0-t1, a positive duty cycle for the MOS switch to turn on is formed. The larger the positive duty cycle, the higher the brightness of the load, and vice versa.

[0036] In one embodiment, the dimmer also includes anti-flicker circuitry, such as... Figure 6The anti-flicker circuit shown includes a PWM positive pulse rising edge lock circuit M4 and a PWM negative pulse falling edge lock circuit M5. The PWM positive pulse rising edge lock circuit M4 includes transistors Q109 and U106A. The base of transistor Q109 is connected to the base of transistor U215A in MOS driver circuit M6 via resistor R135 and emitter follower circuit U218A. The emitter of transistor Q109 is connected to the base of transistor U106A via capacitor C109. The collector of transistor U106A is connected to voltage divider module. Both the collector of transistor Q109 and the emitter of transistor U106A are connected to the power supply voltage VCC. The PWM negative pulse falling edge lockout circuit M5 includes transistors Q101, U102A, U102B, and U101B. The bases of transistors U102A and U102B are connected to the base of transistor U215A in the MOS driver circuit M6 via the emitter follower circuit U218A. The emitter of transistor U102A is connected to the emitter of transistor U102B. The collector of transistor U102A is connected to the power supply voltage VCC, and the collector of transistor U102B is grounded. The collector of transistor Q101 is connected to the bases of transistors U102A and U102B respectively. The base of transistor Q101 is connected to the collector of transistor U101B. The base of transistor U101B is connected to the emitter of transistor U102A via resistor R105. The emitter of transistor U101B is connected to the PWM control circuit M3 via resistor R107.

[0037] Specifically, at the zero-crossing point t0 of the AC voltage, the voltage at the voltage divider point A drops, the PWM pulse changes from low to high and rises, and the voltage at node C of the MOS drive circuit M6 also rises. At this time, the voltage at node C turns on transistor Q109 and turns off U106A through transistor U218B and resistor R135, so that the voltage at voltage divider point A drops even lower more quickly, stabilizing the rising edge of the PWM pulse and quickly reaching a high level and locking in.

[0038] The PWM positive pulse rising edge locking circuit M4 can effectively prevent load flickering caused by the blurring of the rising edge of the PWM pulse due to the critical voltage jitter at the voltage divider point A.

[0039] At time t1, the voltage at node C of the MOS drive circuit M6 drops, causing transistor U102A to turn off and U102B to turn on via the emitter follower circuit U218B; transistor U101B turns on via resistor R105, and transistor Q101 turns on to lock the states of transistors U102A and U102B; after transistor U101B turns on, the voltage at point D in the PWM negative pulse locking circuit M5 drops via resistor R107, thereby causing transistors U204A to turn off and U209B to turn on in the PWM control circuit M3, and U209A to turn off, which in turn causes the reference voltage at the midpoint of potentiometer VR1 to drop; via transistor U207A turning on, transistor Q203, resistor R218, and transistor Q205 cause the voltage at point C to drop even faster.

[0040] Since the zero-crossing signal before the output terminal B of the zero-crossing signal detection circuit M2 will oscillate between VDS of the MOS switch when the MOS switch is turned off, causing voltage fluctuations at the Vin+ node, the design of lowering the reference voltage at the midpoint of potentiometer VR1 in the PWM negative pulse falling edge lock circuit M5 to stabilize the falling edge of the PWM pulse can effectively avoid load flickering caused by false detection of the zero-crossing signal due to voltage fluctuation interference.

[0041] In one embodiment, the dimmer further includes a protection unit, which includes a load overvoltage protection circuit M7 and a lightning strike protection circuit M8; the load overvoltage protection circuit M7 includes a transistor Q108, and the lightning strike protection circuit M8 includes transistors U103A and U103B; the AC input voltage is connected to the base of transistor Q108 via a diode D105, a varistor RV100, a resistor R139, and a resistor R125 connected in series; the collector of transistor Q108 is connected to the base of transistor U209B in the PWM control circuit M3, and the emitter is grounded; resistor R12... 5. Connect one end of resistor R139 to one end of resistor R124, and ground the other end of resistor R124; connect one end of resistor R139 to varistor RV100 to the emitter of transistor U103A, and connect one end of resistor R139 to resistor R125 to the base of transistor U103A via resistor R123; connect the collector of transistor U103A to the collector of transistor U103B; connect the emitter of transistor U103A to DC power supply via diode D103; connect the base and emitter of transistor U103B to MOS switching circuit.

[0042] Specifically, when the AC input voltage is too high, the voltage at the Vin+ node also increases. When the voltage exceeds the rated value of the varistor RV100, current flows through RV100 and increases the voltage across resistor R124. Through resistor R125, transistor Q108 is turned on, and the collector output voltage of transistor Q108 is 0. This causes transistor U209B in the PWM control circuit M3 to turn on and U209A to turn off. The reference voltage at the midpoint of potentiometer VR1 is 0. Then, the MOS switches Q300 and Q301 in the MOS switching circuit M1 are immediately and quickly turned off, and the load is turned off to protect the load from damage caused by AC input overvoltage.

[0043] When a lightning strike voltage is applied to the AC input, a large voltage is generated on the DC power supply Vdc+, causing the varistor RV100 to break down and a large current to flow through it. This results in a large voltage drop across resistor R139, causing transistors U103A and U103B to conduct. MOS switches Q300 and Q301 in the MOS switching circuit M1 are then turned on, allowing the lightning strike current on the input live wire to flow through MOS switches Q300 and Q301. This effectively protects the voltage at the DC power supply Vdc+ node from exceeding the rated withstand voltage of each component in the dimmer's power circuit, thus protecting the dimmer itself from damage.

[0044] In one embodiment, the dimmer further includes a low-power power supply circuit M9, which includes a capacitor C108 and transistors Q102, Q105, Q106, Q107, and U203B. The collector of transistor Q102 is connected to the collector of transistor Q107 via resistors LD103, LD100, and R140 connected in series. The emitter of transistor Q102 is connected to the power supply voltage VCC via resistor R101. The base of transistor Q102 is connected to the collector of transistor Q105 via resistor R114. The emitter of transistor Q105 is connected to the base of transistor Q106. The base of transistor Q105 is connected to the collector of transistor Q106; the emitter of transistor Q106 is connected to the base of transistor Q107; the base of transistor Q106 is connected to the base of transistor Q107 via resistor R121; the emitter of transistor Q107 is connected to the DC power supply Vdc+ via resistor R122; the base of transistor U203B is connected to the power supply voltage VCC via resistor R210; the emitter of transistor U203B is grounded via diode D201; the collector of transistor U203B is connected to the base of transistor Q102 via resistor R213; one end of capacitor C108 is connected to the power supply voltage VCC, and the other end is grounded.

[0045] Specifically, in the low-power power supply circuit M9, current is provided by transistors Q107 and Q102, regulating transistors, and resistors R122, R140, LD100, LD103, and R101, while capacitor C108 performs filtering. A constant voltage loop is formed by diode D201, resistor R210, transistor U203B, and resistor R213 to control the base current of transistor Q102 to keep the power supply voltage VCC constant.

[0046] A constant current source composed of resistor R121, transistors Q106 and Q105, and resistor R114 provides the base current to transistors Q107 and Q102. This effectively accommodates a wide range of input voltages and the dynamic load capabilities of each control section, effectively improving power supply efficiency and reducing losses across the entire AC input waveform. This allows for compatibility with a wider range of power loads, enhancing market adaptability and providing a better user experience.

[0047] The high-power dimmer of this invention divides the AC input voltage through a voltage divider module of a zero-crossing signal detection circuit, and then obtains an output voltage through a shaping module and a positive feedback module. This output voltage is then transmitted to a PWM control circuit. The PWM control circuit determines the positive pulse width duration based on the output voltage and controls the MOS drive circuit to turn the MOS switch circuit on and off. The output of the MOS switch circuit is connected to the load, thereby achieving dimming of the load. Simultaneously, the PWM control circuit is also connected to an anti-flicker circuit, which is connected to the zero-crossing signal detection circuit. The anti-flicker circuit locks the rising edge of the PWM positive pulse and the falling edge of the PWM negative pulse, thereby preventing flickering of the load.

[0048] The above descriptions are merely preferred embodiments of this application, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A high-power dimmer, characterized in that, The dimmer includes a zero-crossing signal detection circuit, a PWM control circuit, a MOS drive circuit, and a MOS switching circuit. The zero-crossing signal detection circuit includes a voltage divider module, a shaping module, and a positive feedback module. The voltage divider module divides the AC input voltage to obtain a voltage divider point. The shaping module and the positive feedback module are connected in parallel between the voltage divider point and the output terminal of the zero-crossing signal detection circuit. The voltage divider point voltage is then processed by the shaping module and the positive feedback module to obtain an output voltage at the output terminal of the zero-crossing signal detection circuit. The output terminal of the zero-crossing signal detection circuit is connected to the PWM control circuit, which determines the positive pulse width duration based on the output voltage. The PWM control circuit is connected to the MOS drive circuit, and the output terminal of the MOS drive circuit is connected to the MOS switch circuit to turn the MOS switch circuit on and off. The voltage divider module includes resistors R120, R117, R113, and R231 connected in series. One end of resistor R120 is connected to the AC input voltage, and the other end is connected to resistor R117. One end of resistor R231 is connected to resistor R113, and the other end is grounded. The positive feedback module includes transistors U213A, U213B, and Q204. The collector of transistor U213A is connected to the voltage divider point, and its base is connected to the emitter of transistor Q204. The base and collector of U213B are both connected to the base of transistor U213A. The base of transistor Q204 is connected to the output terminal of the zero-crossing signal detection circuit. The shaping module includes transistors U211B, U211A, U202B, U202A, and U210A connected in series. The collector of transistor U211B is connected to the base of transistor U211A. The collector of transistor U211A is connected to the base of transistor U202B, the emitter of transistor U202B is connected to the base of transistor U202A, and the collector of transistor U202A is connected to the base of transistor U210A. The collector of transistor U210A is connected to the output terminal of the zero-crossing signal detection circuit. The base of transistor U211B is connected to one end of resistor R231. The AC input voltage is divided by the voltage divider module to obtain the voltage divider point voltage at one end of resistor R231. The voltage divider point voltage turns on transistor U211B, and the output voltage is obtained at the output terminal of the zero-crossing signal detection circuit through the shaping of transistors U211A, U202B, U202A, and U210A and the positive feedback of transistors Q204, U213A, and U213B. The PWM control circuit includes a potentiometer VR1, a capacitor C214, and transistors U204A, U212A, U209A, U209B, U207A, U207B, and Q203. The emitter of transistor U204A is connected to the base of transistor U209B via resistor R224. The base of transistor U209A and the emitter of transistor U209B are connected to the power supply voltage via resistor R225. The emitter of transistor U209A is connected to the potentiometer VR1, and the collector is connected to the power supply voltage. The collector of transistor U209B is grounded. The base of transistor U212A is connected to the output of the zero-crossing signal detection circuit, and its collector is connected to the base of transistor U207B. The emitter of transistor U207B is connected via resistor R220, and its collector is connected to one end of capacitor C214, with the other end of capacitor C214 grounded. The emitter of transistor U207A is connected to the collector of transistor U207B, its base is connected to potentiometer VR1, and its collector is connected to the base of transistor Q203. The collector of transistor Q203 is connected to the MOS driving circuit via resistor R218.

2. The high-power dimmer according to claim 1, characterized in that, The MOS driving circuit includes transistors U215A, U215B, and Q205 forming a half-bridge drive, and resistors R241, R243, and R242. The base of transistor Q205 is connected to the PWM control circuit. The bases of transistors U215A and U215B are both connected to the emitter of transistor Q205. The emitter of transistor U215A is connected to the emitter of transistor U215B via resistors R243 and R242 in series. The collector of transistor U215A is connected to the power supply voltage, and the collectors of transistors Q205 and U215B are both grounded. One end of resistor R241 is connected to the power supply voltage, and the other end is connected to the base of transistors U215A and U215B and the emitter of transistor Q205.

3. The high-power dimmer according to claim 1, characterized in that, The MOS switching circuit includes MOS switches Q300 and Q301. The gate of MOS switch Q300 is connected to the output terminal of the MOS driving circuit via resistor R300, and the gate of MOS switch Q301 is connected to the output terminal of the MOS driving circuit via resistor R301. The drains of MOS switches Q300 and Q301 are connected to the live wire terminals L1 and L2, respectively. The sources of MOS switches Q300 and Q301 are both grounded.

4. The high-power dimmer according to claim 1, characterized in that, The dimmer also includes an anti-flicker circuit, which comprises a PWM positive pulse rising edge lock-in circuit and a PWM negative pulse falling edge lock-in circuit. The PWM positive pulse rising edge lock-in circuit includes transistors Q109 and U106A. The base of transistor Q109 is connected to the base of transistor U215A in the MOS driver circuit via resistor R135 and transistor U218A. The emitter of transistor Q109 is connected to the base of transistor U106A via capacitor C109. The collector of transistor U106A is connected to the voltage divider module. Both the collector of transistor Q109 and the emitter of transistor U106A are connected to the power supply voltage. The PWM negative pulse falling edge lock-in circuit includes transistors Q101, U102A, and U102... B. U101B, the bases of transistors U102A and U102B are connected to the base of transistor U215A in the MOS drive circuit via transistor U218A. The emitter of transistor U102A is connected to the emitter of transistor U102B. The collector of transistor U102A is connected to the power supply voltage, and the collector of transistor U102B is grounded. The collector of transistor Q101 is connected to the bases of transistors U102A and U102B respectively. The base of transistor Q101 is connected to the collector of transistor U101B. The base of transistor U101B is connected to the emitter of transistor U102A via resistor R105. The emitter of transistor U101B is connected to the PWM control circuit via resistor R107.

5. The high-power dimmer according to claim 1, characterized in that, The dimmer also includes a protection unit, which comprises a load overvoltage protection circuit and a lightning strike protection circuit. The load overvoltage protection circuit includes a transistor Q108, and the lightning strike protection circuit includes transistors U103A and U103B. The AC input voltage is connected to the base of transistor Q108 via a series connection of diode D105, varistor RV100, resistor R139, and resistor R125. The collector of transistor Q108 is connected to the PWM control circuit, and its emitter is grounded. Resistor R125 connects one end of resistor R139 to resistor R1... One end of resistor R14 is connected, and the other end of resistor R124 is grounded; one end of resistor R139 connected to varistor RV100 is connected to the emitter of transistor U103A, and one end of resistor R139 connected to resistor R125 is connected to the base of transistor U103A via resistor R123; the collector of transistor U103A is connected to the collector of transistor U103B; the emitter of transistor U103A is connected to DC power supply via diode D103; the base and emitter of transistor U103B are connected to the MOS switching circuit.

6. The high-power dimmer according to claim 1, characterized in that, The dimmer also includes a low-power power supply circuit, which includes a capacitor C108 and transistors Q102, Q105, Q106, Q107, and U203B. The collector of transistor Q102 is connected to the collector of transistor Q107 via resistors LD103, LD100, and R140 connected in series. The emitter of transistor Q102 is connected to the power supply voltage via resistor R101. The base of transistor Q102 is connected to the collector of transistor Q105 via resistor R114. The emitter of transistor Q105 is connected to the base of transistor Q106. The base of transistor U106 is connected to the collector of transistor Q106; the emitter of transistor Q106 is connected to the base of transistor Q107; the base of transistor Q106 is connected to the base of transistor Q107 via resistor R121; the emitter of transistor Q107 is connected to a DC power supply via resistor R122; the base of transistor U203B is connected to the power supply voltage via resistor R210; the emitter of transistor U203B is grounded via diode D201; the collector of transistor U203B is connected to the base of transistor Q102 via resistor R213; one end of capacitor C108 is connected to the power supply voltage, and the other end is grounded.

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