Long-distance LED lamp light modulation circuit through controllable rectification

[0041] Hereinafter, the present invention will be further described in detail with reference to the accompanying drawings and embodiments, but the embodiments of the present invention are not limited thereto.

[0042] The block diagram of the system structure of the present invention is as figure 1 As shown, it consists of a rectifier control unit and an LED lamp brightness adjustment unit. The rectification control unit inputs a single-phase 220V AC power supply from the phase line input terminal L and the neutral line input terminal N, and outputs a controllable rectification voltage from the first controllable rectification output terminal AC1 and the second controllable rectification output terminal AC2. The LED lamp brightness adjustment unit inputs a controllable rectification voltage from the first controllable rectification input terminal AC1 and the second controllable rectification input terminal AC2 and controls the brightness of the LED lamp.

[0043] The structure of the rectifier control unit is as figure 2 As shown, it is composed of a control power module, a controllable rectifier module, a zero-crossing detection module, a single-chip microcomputer control module, a trigger control module, and a brightness setting module.

[0044] Examples of controllable rectifier modules image 3 As shown, it is composed of rectifier bridge UR1, bidirectional thyristor V1, bidirectional thyristor V2, bidirectional thyristor V3, and bidirectional thyristor V4. The two AC input terminals of the rectifier bridge UR1 are respectively connected to the phase line input terminal L and the neutral line input terminal N. The positive terminal of the rectifier output is connected to the second anode of the triac V3, and the negative terminal of the rectifier output is connected to the second anode of the triac V4. Anode; the first anode of the bidirectional thyristor V1 and the first anode of the bidirectional thyristor V3 are connected in parallel to the first controllable rectifier output terminal AC1; the second anode of the bidirectional thyristor V1 is connected to the phase line input terminal L; the second anode of the bidirectional thyristor V2 An anode is connected in parallel with the first anode of the bidirectional thyristor V4 and then connected to the second controllable rectification output terminal AC2; the second anode of the bidirectional thyristor V2 is connected to the neutral input terminal N.

[0045] The trigger pulse of the triac V1 is input from its control pole K11 and the first anode K12, the trigger pulse of the triac V2 is input from its control pole K21 and the first anode K22, and the trigger pulse of the triac V3 is from its control pole K31 and first anode. The anode K32 is input, and the trigger pulse of the bidirectional thyristor V4 is input from its control pole K41 and the first anode K42.

[0046] The rectifier bridge UR1 adopts a single-phase rectifier bridge stack, or uses 4 diodes to form a single-phase rectifier bridge instead.

[0047] The trigger control module is a circuit that satisfies the following functions: equipped with an AC control input terminal and a rectifier control input terminal; when the AC control signal input from the AC control input terminal is valid, the trigger control module controls the triac V1 and triac V2 to trigger the conduction at zero crossing On; when the AC control signal input from the AC control input terminal is invalid, the trigger control module controls the triac V1 and triac V2 to cut off after zero crossing; when the rectifier control signal input from the rectifier control input terminal is valid, the trigger control module controls the triac V3 and When the bidirectional thyristor V4 crosses zero, it is triggered to turn on; when the rectification control signal input from the rectification control input terminal is invalid, the trigger control module controls the bidirectional thyristor V3 and the bidirectional thyristor V4 to cut off after zero crossing.

[0048] Example of trigger control module Figure 4 As shown, it is composed of zero-crossing trigger optocoupler U1-U4, input current-limiting resistors R1-R4, and output current-limiting resistors R5-R8, with AC control input KJ and rectification control input KZ. The zero-crossing trigger optocoupler U1-U4 includes an input light-emitting diode, an output light-controlled bidirectional thyristor, and a zero-crossing trigger circuit. The model of the zero-crossing trigger optocoupler U1-U4 can be selected from MOC3041, MOC3042, MOC3043, MOC3061, MOC3062, MOC3063.

[0049] The input current limiting resistor R1 is connected in series with the input light emitting diode of the zero-crossing trigger optocoupler U1 and then connected in parallel to the first DC working power supply VDD1 and the AC control input terminal KJ. The input current-limiting resistor R1 is connected in series with the anode of the input LED of the zero-crossing trigger optocoupler U1, such as Figure 4 As shown; the input current-limiting resistor R1 can also be connected in series with the cathode of the input light-emitting diode of the zero-crossing trigger optocoupler U1.

[0050] The input current-limiting resistor R2 is connected in series with the input light-emitting diode of the zero-crossing trigger optocoupler U2 and then connected in parallel to the first DC working power supply VDD1 and the AC control input terminal KJ. The input current-limiting resistor R3 is connected in series with the input light-emitting diode of the zero-crossing trigger optocoupler U3 and then connected in parallel to the first DC working power supply VDD1 and the rectification control input terminal KZ. The input current limiting resistor R4 is connected in series with the input light-emitting diode of the zero-crossing trigger optocoupler U4 and then connected in parallel to the first DC working power supply VDD1 and the rectifier control input terminal KZ. The input current-limiting resistors R2-R4 can be connected in series with the anode of the input LED of the corresponding zero-crossing trigger optocoupler, such as Figure 4 As shown; it can also be connected in series with the cathode of the input light-emitting diode of the corresponding zero-crossing trigger optocoupler.

[0051] The output current limiting resistor R5 is connected in series with the internal output of the zero-crossing trigger optocoupler U1 and then connected in parallel to the control pole K11 and the first anode K12 of the two-way thyristor V1; the output current limiting resistor R6 and the zero-crossing trigger optocoupler U2 internal output The light-controlled bidirectional thyristor is connected in series and then connected in parallel to the control pole K21 and the first anode K22 of the bidirectional thyristor V2; the output current limiting resistor R7 is connected in series with the internal output of the zero-crossing trigger optocoupler U3 and then connected in parallel to the bidirectional thyristor V3. Pole K31 and the first anode K32; the output current limiting resistor R8 is connected in series with the internal output light-controlled bidirectional thyristor of the zero-crossing trigger optocoupler U4 and then connected in parallel to the control pole K41 and the first anode K42 of the bidirectional thyristor V4.

[0052] The control part of the rectification control unit includes a control power module, a zero-crossing detection module, a single-chip control module, and a brightness setting module. The embodiment circuit is as follows Figure 5 Shown.

[0053] The control power module inputs single-phase 220V AC power, and outputs the first DC working power VDD1 provided to the rectifier control unit. Figure 5 In the embodiment, the control power module is composed of a diode D01, a diode D02, a diode D03, a diode D04, a capacitor C1, a resistor R01, and a voltage regulator tube DW01. The diode D01, the diode D02, the diode D03, and the diode D04 form a single-phase rectifier bridge for the control power supply; the capacitor C1 plays a filtering role and is connected in parallel with the rectifier voltage output end of the single-phase rectifier bridge for the control power supply; the resistor R01 and the voltage regulator tube DW01 form a voltage stabilizing circuit . The first DC working power supply VDD1 is output from the cathode of the voltage regulator tube DW01. The rectifier negative terminal of the control power single-phase rectifier bridge is the common ground.

[0054] The control power module can also adopt other implementation schemes. The control power supply single-phase rectifier bridge composed of diode D01, diode D02, diode D03, and diode D04 can be replaced by a single-phase rectifier bridge stack. The voltage stabilizing circuit composed of resistor R01 and zener tube DW01 can use a DC/DC regulator or Instead of a three-terminal regulator.

[0055] The zero-crossing detection module is a circuit with the following functions: equipped with a zero-crossing voltage input terminal and a zero-crossing pulse output terminal; the zero-crossing voltage input terminal is connected to the phase line input terminal L; the zero-crossing pulse output from the zero-crossing pulse output terminal is a positive pulse ; The zero-crossing pulse corresponds to the positive half-wave width of the single-phase 220V AC power supply input by the rectifier control unit; the width of the zero-crossing pulse is less than the positive half-wave width of the single-phase 220V AC power supply.

[0056] Figure 5 In the embodiment, the zero-crossing detection module is a detection and shaping circuit, which is composed of a diode D1, a resistor R9, and a voltage regulator tube DW1. The two ends of the resistor R9 are respectively connected to the cathode of the diode D1 and the cathode of the zener tube DW1, the anode of the diode D1 is connected to the phase line input terminal L, and the anode of the zener tube DW1 is connected to the common ground. The cathode of the voltage regulator tube DW1 is the zero-crossing pulse output terminal that outputs the zero-crossing pulse.

[0057] The brightness setting module is equipped with a brightness setting signal output terminal to output the brightness setting signal. Figure 5 In the embodiment, the brightness setting module is a BCD rotary encoder, and the output brightness setting signal is BCD code 0000-1001, where BCD code 0001-1001 represents brightness 1-9, and when BCD code is 0000, it represents brightness 0. Turn off the LED light.

[0058] The brightness setting module may also use a potentiometer to divide the first DC working power supply VDD1, and the obtained brightness setting signal is the brightness setting voltage. Divide the given brightness output voltage of the potentiometer into averagely n +1 interval, the lowest voltage interval corresponds to the code 0000 of the BCD rotary encoder, the brightness level of the given brightness signal is brightness 0; other intervals are respectively related to brightness 1- n correspond; n It is an integer greater than or equal to 2, and the typical value is 9.

[0059] The single-chip control module includes one input terminal for brightness setting signal, one input terminal for capturing signal, and two output terminals for level signal. 1 channel of the brightness setting signal input terminal is connected to the brightness setting signal output terminal of the brightness setting module; 1 channel of capture signal input terminal is connected to the zero-crossing pulse output terminal of the zero-crossing detection module, inputting the zero-crossing pulse; 2 channels of level The signal output terminals are the AC control output terminal KJ and the rectification control output terminal KZ, which are respectively connected to the AC control input terminal KJ and the rectification control input terminal KZ of the trigger control module.

[0060] Figure 5 In the embodiment, the single-chip control module is composed of single-chip MCU1 and crystal oscillator XT1, and the model of single-chip MCU1 is MSP430G2553. P1.7-P1.4 of MCU1 is the input end of the brightness setting signal, and the BCD code of the brightness setting module is input from P1.7-P1.4. If the brightness setting module uses a potentiometer, the analog voltage input terminal A0 (P1.0) of MCU1 is the brightness setting signal input terminal, and the output voltage of the potentiometer is connected to the analog voltage input terminal A0 (P1.0) of MCU1 ). The single-chip microcomputer MCU1 reads the BCD code input from P1.7-P1.4, or performs A/D conversion on the brightness given voltage input from the analog voltage input terminal A0 to obtain the brightness level of the given brightness signal. P2.0 of MCU1 is the capture signal input terminal and is connected to the zero-crossing pulse output terminal of the zero-crossing detection module. P1.1 and P1.2 of MCU1 are level signal output terminals, among which P1.1 is AC control output terminal KJ, P1.2 is rectification control output terminal KZ; AC control output terminal KJ and rectification control output terminal KZ are respectively Connect to the AC control input terminal KJ and the rectifier control input terminal KZ of the trigger control module.

[0061] The first controllable rectification output terminal AC1 and the second controllable rectification output terminal AC2 of the rectification control unit output the controllable rectification voltage. The rectification control unit sends the brightness of different brightness levels by controlling the number of consecutive rectification waveform cycles in the controllable rectification voltage. control signal. The effective value of the controllable rectification voltage is the same as the effective value of the single-phase 220V AC power supply input by the rectification control unit.

[0062] In the brightness control signal, the brightness level is represented by the number of consecutive rectified waveform cycles. In the embodiment, the brightness control signal shares the brightness 1- n Of n Brightness levels. When the brightness level of the given brightness signal is brightness 0, the rectifier control unit turns off the LED light and does not send the brightness control signal. The brightness of the brightness control signal brightness level 1- n The brightness of a given signal brightness level with brightness 1- n There is a one-to-one correspondence.

[0063] The period in the number of rectified waveform cycles is the power frequency period, and the power frequency period is 20ms; the number of rectified waveform cycles is the number of power frequency cycles occupied by the rectified waveform; the rectified waveform of 1 cycle is composed of 2 rectified half waves, and the first One rectified half-wave corresponds to the positive half-wave of the single-phase 220V AC power supply, and the second rectified half-wave corresponds to the negative half-wave of the single-phase 220V AC power supply.

[0064] The waveform example when the rectifier control unit sends the brightness control signal is as follows Image 6 Shown. Image 6 The transmission shown is a brightness control signal with a brightness level of brightness 3.

[0065] The single-chip control module sends out a brightness level of brightness K The steps of the brightness control signal are as follows:

[0066] Step 1, wait until the rising edge of the zero-crossing pulse is received, and then go to step 2;

[0067] Step 2. Stop AC output and start rectifying output;

[0068] Step 3. Count the rising edge of the received zero-crossing pulse until the count value reaches K When entering step 4;

[0069] Step 4. Stop rectifying output and start AC output.

[0070] When the LED light is not turned off and the rectifier control unit is in the normal state of not sending out the brightness control signal, the single-chip control module controls the AC control output terminal KJ to output an effective signal, and the rectifier control output terminal KZ outputs an invalid signal, and the zero crossing triggers the optocouplers U1 and U2 The input light-emitting diodes of the optocouplers U3 and U4 are turned off when the zero-crossing triggers the input light-emitting diodes of the optocouplers U3 and U4, the bidirectional thyristor V1 and the bidirectional thyristor V2 are turned on, the bidirectional thyristor V3 and the bidirectional thyristor V4 are turned off, and the first controllable rectifier output terminal AC1 The controllable rectification voltage output by the second controllable rectification output terminal AC2 is an AC voltage. in Figure 4 In the illustrated embodiment, the signals of the AC control output terminal KJ and the rectification control output terminal KZ output by the single-chip control module are active low.

[0071] Figure 5 The zero-crossing pulse output by the zero-crossing detection module shown corresponds to the positive half-wave of the single-phase 220V AC power supply input by the rectification control unit, and the width of the zero-crossing pulse is less than the positive half-wave width. The MCU control module detects the Image 6 After the rising edge of the zero-crossing pulse corresponding to half-wave 1, go to step 2. The stop AC output and start rectification output means to control the AC control output KJ to output an invalid signal and stop the AC output; the rectification control output KZ to output an effective signal to start the rectification output; zero crossing triggers the input of the optocoupler U1 and U2 to emit light The diode is cut off, and the zero crossing triggers the input light-emitting diodes of the optocouplers U3 and U4 to turn on. The next zero-crossing point of the single-phase 220V AC power input from the rectifier control unit, ie Image 6 The zero crossing point 2 shown starts, the bidirectional thyristor V1 and the bidirectional thyristor V2 are turned off, the bidirectional thyristor V3 and the bidirectional thyristor V4 are turned on, and the controllable rectification voltage output by the first controllable rectification output terminal AC1 and the second controllable rectification output terminal AC2 Is the rectified voltage. Pair continuous K After the rectification of the alternating voltage wave of three cycles, the microcontroller control module counts the rising edge of the received zero-crossing pulse, and the count value reaches K When Image 6 In the illustrated embodiment, the counted third zero-crossing pulse is Image 6 Corresponds to the middle half wave 3. At this time, the rectification output is stopped, and the AC output starts, then at the next zero crossing point, ie Image 6 From the zero crossing point 4 shown, the bidirectional thyristor V1 and the bidirectional thyristor V2 are turned on, the bidirectional thyristor V3 and the bidirectional thyristor V4 are turned off, and the controllable rectification voltage output by the first controllable rectification output terminal AC1 and the second controllable rectification output terminal AC2 For AC voltage, the rectifier control unit returns to the normal state of maintaining no brightness control signal.

[0072] The method for the rectifier control unit to send the brightness control signal is as follows Figure 7 Shown, including:

[0073] Step A, read the given brightness signal;

[0074] Step B, judge whether to turn off the LED light, if yes, control to turn off the LED light, go to step D; otherwise go to step C;

[0075] Step C: Send a brightness control signal once;

[0076] Step D: Determine whether the brightness has changed, and the brightness has changed, and then return to step B; if the brightness does not change, return to step D.

[0077] The method of judging whether to turn off the LED light is to judge whether the brightness level of the given brightness signal is 0; when the brightness level is 0, the LED light is turned off. The way to determine whether the brightness has changed is to determine whether the brightness level of a given signal of brightness has changed.

[0078] The method of controlling to turn off the LED light is to stop the rectification output and stop the AC output; at this time, the first controllable rectification output terminal AC1 and the second controllable rectification output terminal AC2 do not output the controllable rectification voltage.

[0079] The structure of the LED light brightness adjustment unit is as follows Figure 8 As shown, it is composed of a regulating power module, a waveform sampling module, a single-chip regulating module, and an LED driving module.

[0080] The adjustment part of the LED lamp brightness adjustment unit includes an adjustment power supply module, a waveform sampling module, and a single-chip adjustment module. Picture 9 Shown.

[0081] The adjusting power module provides the second DC working power VDD2 for the LED lamp brightness adjusting unit. Picture 9 In the embodiment, the regulating power module is composed of a diode D05, a diode D06, a diode D07, a diode D08, a capacitor C2, a resistor R02, and a voltage regulator tube DW02. The diode D05, the diode D06, the diode D07, and the diode D08 form the single-phase rectifier bridge of the regulating power supply; the capacitor C2 is connected in parallel with the rectifying voltage output end of the single-phase rectifier bridge of the regulating power supply to play a filtering role; the resistor R02 and the voltage regulator tube DW02 constitute the voltage stabilizing circuit . The second DC working power supply VDD2 is output from the cathode of the voltage regulator tube DW02. Regulate the power supply single-phase rectifier bridge as the reference ground.

[0082] Regulating the power supply module can also adopt other implementation schemes. The regulated power supply single-phase rectifier bridge composed of diode D05, diode D06, diode D07, and diode D08 can be replaced by a single-phase rectifier bridge stack. The voltage stabilizing circuit composed of resistor R02 and regulator tube DW02 can be a DC/DC regulator or Instead of a three-terminal regulator.

[0083] The waveform sampling module is a circuit with the following functions: the waveform sampling module has a sampling waveform input terminal and a sampling pulse output terminal; the sampling waveform input terminal is connected to the first controllable rectification input terminal; the waveform sampling module connects the first controllable rectification input terminal The waveform whose potential is higher than that of the second controllable rectification input terminal is detected and limited to obtain a sampling pulse; the positive pulse of the sampling pulse corresponds to the waveform whose potential is higher than the potential of the second controllable rectification input terminal .

[0084] Picture 9 In the embodiment, the waveform sampling module is a detection and shaping circuit, which is composed of a diode D2, a resistor R12, and a voltage regulator tube DW2. The two ends of the resistor R12 are respectively connected to the cathode of the diode D2 and the cathode of the zener tube DW2; the anode of the diode D2 is the sampling waveform input terminal and is connected to the first controllable rectifier input terminal AC1; the anode of the zener tube DW2 is connected to the reference ground; The cathode of tube DW2 is the sampling pulse output terminal.

[0085] The single-chip adjustment module has a capture input terminal and a PWM pulse output terminal, and the capture input terminal is connected to the sampling pulse output terminal of the waveform sampling module. Picture 9 In the embodiment, the single-chip adjustment module is composed of single-chip MCU2 and crystal oscillator XT2, the model of single-chip MCU2 is MSP430G2553, the capture input terminal of MCU2 is P2.0, and the PWM pulse output terminal is P1.2.

[0086] The LED drive module is used to drive the LED lamp to light up. It is equipped with a PWM brightness adjustment signal input terminal, and can be directly connected to a 220V AC power supply without a transformer or directly input a DC power supply of 300V or more. Picture 10 The circuit shown is only one embodiment of the circuit. The PWM brightness adjustment signal input end of the LED drive module is connected to the PWM pulse output end of the single-chip adjustment module.

[0087] Picture 10 Among them, the LED drive module is composed of LED driver U5, diode D11, diode D12, diode D13, diode D14, capacitor C3, capacitor C4, inductor LG, fast recovery diode D15, switch tube VD, resistor R14, and resistor R15. The model of the LED driver U5 is HV9910.

[0088] Picture 10 Among them, diode D11, diode D12, diode D13, and diode D14 form a single-phase bridge rectifier circuit. The two AC input terminals of the single-phase bridge rectifier circuit are respectively connected to the first controllable rectification input terminal AC1 and the second controllable rectification input terminal AC2, the negative terminal of the DC output is connected to the reference ground, and the positive terminal of the DC output is connected to the capacitor C3 The anode is the power input terminal VIN of the LED driver U5, one end of the inductor LG, and the cathode of the fast recovery diode D15. The ground input terminal GND of the LED driver U5 is connected to the reference ground. The negative pole of capacitor C3 is connected to the reference ground. The anode of the fast recovery diode D15 is connected with the drain of the switch tube VD as the negative connection terminal LED- of the high-power LED lamp, and the other end of the inductor LG is used as the positive connection terminal LED+ of the high-power LED lamp. The source of the switch tube VD is connected to one end of the resistor R14 and then connected to the LED current detection terminal CS of the LED driver U5; the other end of the resistor R14 is connected to the reference ground. The gate of the switch tube VD is connected to the driving terminal GATE of the LED driver U5. One end of the resistor R15 is connected to the oscillation frequency control terminal RT of the LED driver U5, and the other end is connected to the reference ground. The anode of the capacitor C4 is connected to the control voltage output terminal VDD and the linear current control terminal LD ​​of the LED driver U5, and the cathode is connected to the reference ground. The enable control terminal PWM_D of the LED driver U5 is the PWM brightness adjustment signal input terminal. The LED light is connected to the positive polarity connection terminal LED+ and the negative polarity connection terminal LED-.

[0089] The LED lamp brightness adjustment unit receives the brightness control signal and adjusts the brightness of the LED lamp, the method is as follows Picture 11 Shown, including:

[0090] Step 1: Initialize, set the initial brightness level of the LED light;

[0091] Step two, adjust the LED brightness;

[0092] Step three, judge whether there is a brightness control signal; if there is no brightness control signal, return to step three; if there is a brightness control signal, go to step four;

[0093] Step 4: Receive the brightness control signal;

[0094] Step five, return to step two.

[0095] The initial brightness level of the LED light can be set as n One of the brightness levels, for example, set the initial brightness level to level 1.

[0096] The method of adjusting the brightness of the LED is that the single-chip adjustment module calculates the PWM value according to the set or received brightness level of the LED lamp, and sends out the corresponding PWM pulse.

[0097] The method for determining whether there is a brightness control signal is to determine whether the controllable rectification voltage input from the first controllable rectification input terminal AC1 and the second controllable rectification input terminal AC2 is a rectified voltage.

[0098] The method of receiving the brightness control signal is to determine the number of continuous rectification waveform cycles in the controllable rectification voltage; there is continuous in the controllable rectification voltage K When the waveform is rectified in cycles, the brightness level of the brightness control signal is brightness K.

[0099] The function of the waveform sampling module is to detect and reshape the controllable rectified voltage. Picture 9 In the embodiment, the sampling waveform input terminal of the waveform sampling module is connected to the first controllable rectification input terminal AC1, and the waveform of the first controllable rectification input terminal AC1 whose potential is higher than the second controllable rectification input terminal AC2 is detected and limited. Get the sampling pulse. An example of the first sampling pulse with a brightness level of brightness 3 in the brightness control signal is as follows Image 6 (B) Shown. When the controllable rectification voltage is an AC voltage, the sampling pulse is a rectangular wave with a duty ratio of less than 50% and the same frequency as the AC voltage; when the controllable rectification voltage is a rectified voltage, the sampling pulse has a duty ratio close to 100% and the frequency It is a rectangular wave with AC voltage frequency twice. Image 6 In (b), the rectified waveform of 3 consecutive cycles causes 6 narrow negative pulses such as pulse 5-10 appear in the sampling pulse. When the AC voltage frequency is 50Hz, the period of the narrow negative pulse is 10ms; the width of the narrow negative pulse is not Over 1ms, the specific width is related to parameters such as resistor R12, voltage regulator tube DW2, and the amplitude of the controllable rectification voltage.

[0100] The sampling waveform input terminal of the waveform sampling module can also be connected to the second controllable rectification input terminal AC2. The waveform sampling module detects and limits the waveform of the first controllable rectification input terminal AC1 that is lower than the second controllable rectification input terminal AC2. A sample pulse is obtained and output to the capture input terminal of the single-chip adjustment module; at this time, the sample pulse with the brightness level of brightness 3 in the brightness control signal is as follows: Image 6 As shown in (c); when the controllable rectification voltage is an AC voltage, the sampling pulse is a rectangular wave with a duty cycle of less than 50% and the same frequency as the AC voltage; when the controllable rectification voltage is a rectified voltage, the sampling pulse is a low voltage level, Image 6 In (c), the rectified waveform for 3 consecutive cycles causes a low-level pulse with a width slightly greater than 70ms in the sampling pulse, that is, pulse 11.

[0101] The method for judging the number of consecutive rectified waveform cycles in the controllable rectified voltage is: the single-chip adjustment module counts the number of narrow negative pulses in the rectangular wave whose frequency is twice the AC voltage frequency in the sampling pulse, and the count value is 2 K When the number of continuous rectification waveform cycles in the controllable rectification voltage is K; Or the single-chip adjustment module measures the low-level pulse width of more than 20ms in the sampling pulse, and the measured low-level pulse width of more than 20ms is T , Then the number of consecutive rectified waveform cycles in the controllable rectified voltage is K =INT( T/ 20) The function of the INT function is to round off the decimal part.

[0102] The controllable rectification voltage directly supplies power to the adjustment power supply module, LED drive module and waveform sampling module of the LED light brightness adjustment unit. The adjustment power supply module and LED drive module first rectify the controllable rectification voltage, and then after the capacitor filter, Related circuits provide power; when the controllable rectification voltage is zero, the power supply current of the power supply module and LED drive module is also zero; the waveform sampling module is a non-linear resistive load, and when the controllable rectification voltage is zero, the power supply of the waveform sampling module The current is zero. Therefore, when the controllable rectifier voltage is zero, the power supply current it provides to the LED lamp brightness adjustment unit is zero. Therefore, when the rectifier control unit stops the AC output and starts the rectification output at the zero-crossing point of the input single-phase 220V AC power supply, or stops the rectification output and starts the switching of the AC output, the triac V1, the triac V2, and the triac V3, The two-way thyristor V4 can be successfully commutated without causing a short circuit of the power supply.

[0103] The present invention has the following characteristics:

[0104] ① Use the power cord to remotely control the brightness of the LED lights, without a remote control, without a control line;

[0105] ② The brightness of LED lights can be divided into multiple levels according to needs, with the function of turning off the lights;

[0106] ③ The rectified wave is used to transmit the brightness control signal, which will not cause the flicker and the reduction of the power factor of the LED lamp brightness adjustment.