LED dimmer, LED dimming system and control method thereof

Abstract

The present application discloses an LED dimmer, an LED dimming system and a control method thereof. The LED dimmer comprises: a dimming module and a bypass module connected in series between a first and a second AC input terminal, wherein the dimming module receives a dimming control signal and obtains dimming data from the dimming control signal, and the load impedances of the dimming module and the bypass module match each other to form a power carrier loop, thereby superimposing the dimming data on the AC voltage to generate a carrier signal. The LED dimmer integrates a signal receiving module and a bypass module, can provide a carrier signal to multiple LED drive circuits, thereby improving the anti-interference ability, and can simplify the circuit structure and volume of the LED drive circuit packaged in the LED bulb, so that it is suitable for packaging into a small-sized LED bulb.

Description

Technical Field

[0001] The present application relates to power electronics related fields, and in particular, to an LED dimmer, an LED dimming system and a control method thereof. Background Art

[0002] LED lamps have been widely used in the field of lighting. More and more users need dimming devices suitable for LED lamps to adjust the brightness or dim according to environmental needs to reduce energy consumption. Even large crystal lamps or chandeliers using LED lamps also hope to achieve dimming function.

[0003] Unlike lighting devices using a single LED bulb, crystal lamps or chandeliers include a large number of small LED bulbs. Each LED bulb is a module including a housing, an LED lamp contained in the housing, and an LED driving circuit, and the LED lamp is connected to the corresponding LED driving circuit. The LED driving circuit includes a signal receiving module and a power conversion module, the signal receiving module is used to receive a dimming control signal and generate a dimming signal according to the dimming control signal, and the power conversion module controls the output current and / or duty cycle of the LED driving circuit according to the dimming signal, thereby realizing dimming control.

[0004] However, the volume of multiple LED bulbs used in crystal lamps or chandeliers is too small to accommodate existing LED driving circuits. In addition, the housing of the LED bulb is, for example, plastic-coated aluminum material, and the dimming control signal received by the signal receiving module inside the LED bulb is easily interfered. Summary of the invention

[0005] In view of the above problems, the object of the present invention is to provide an LED dimmer, an LED dimming system and a control method thereof, wherein the LED dimmer is used to convert the dimming control signal into a carrier signal, and a signal receiving module and a bypass module are integrated in the LED dimmer to improve the anti-interference ability and reduce the size of the packaged chip in the LED bulb.

[0006] According to one aspect of the present invention, there is provided an LED dimmer, comprising:

[0007] A dimming module and a bypass module connected in series between the first and second AC input terminals,

[0008] The dimming module receives a dimming control signal and obtains dimming data from the dimming control signal. The load impedances of the dimming module and the bypass module match each other to form a power carrier loop, thereby superimposing the dimming data on the AC voltage to generate a carrier signal.

[0009] Optionally, the dimming module includes:

[0010] A first rectifier bridge, wherein an AC input end of the first rectifier bridge is connected to an AC power supply and generates a first DC bus voltage according to the AC voltage;

[0011] A signal receiving module receives a dimming control signal sent externally;

[0012] A control module connected to the signal receiving module to obtain a dimming control signal, and obtain dimming data according to the dimming control signal;

[0013] a carrier signal generator connected to the control module to obtain dimming data and generate a corresponding data signal according to the dimming data; and

[0014] A power transmission module is connected to the carrier signal generator to obtain the data signal, and is connected between the first DC output terminal and the second DC output terminal of the first rectifier bridge to change the load impedance of the first rectifier bridge according to the data signal.

[0015] Optionally, the dimming module also includes a power supply module, wherein the power supply module is connected between the first DC output terminal and the second DC output terminal of the first rectifier bridge, and uses the first DC bus voltage output by the first rectifier bridge to generate an internal power supply voltage of the dimming module.

[0016] Optionally, the dimming module further includes a power supply module and a diode, wherein the diode performs half-wave rectification on the AC voltage, the power supply module is connected to the diode, and the internal power supply voltage of the dimming module is generated using the first DC bus voltage rectified by the diode.

[0017] Optionally, the bypass module includes:

[0018] a second rectifier bridge, wherein an AC input end of the second rectifier bridge is connected to the AC power supply and generates a second DC bus voltage according to the AC voltage;

[0019] A zero-crossing detection module, connected to the first DC output terminal of the second rectifier bridge, and used to detect the zero-crossing moment of the second DC bus voltage;

[0020] A data sampling module, connected to the first DC output terminal of the second rectifier bridge, for obtaining a sampling signal of the second DC bus voltage;

[0021] a first micro control unit connected to the zero-crossing detection module and the data sampling module, configured to obtain the waveform of the carrier signal according to the sampling signal, and generate a switch control signal corresponding to the signal modulation of the carrier signal; and

[0022] an impedance module, connected to the first microcontroller unit to receive the switch control signal, and connected between the first DC output terminal and the second DC output terminal of the second rectifier bridge, and changing the load impedance of the first rectifier bridge according to the switch control signal,

[0023] Wherein, the AC input end of the first rectifier bridge and the AC input end of the second rectifier bridge are connected to the same power supply line of the AC power supply.

[0024] According to another aspect of the present invention, there is provided an LED dimming system, comprising:

[0025] An LED dimmer, the LED dimmer comprising a dimming module and a bypass module connected in series between a first and a second AC input terminal;

[0026] A plurality of LED driving circuits are connected in parallel with the bypass module of the LED dimmer,

[0027] The dimming module receives a dimming control signal and obtains dimming data from the dimming control signal. The load impedances of the dimming module and the bypass module match each other, so that the dimming data is superimposed on the AC voltage to generate a carrier signal.

[0028] The plurality of LED driving circuits receive carrier signals respectively, obtain electric energy and dimming signals according to the carrier signals, and control electric energy transmission according to the dimming signals to achieve dimming.

[0029] Optionally, the dimming module includes:

[0030] A first rectifier bridge, wherein an AC input end of the first rectifier bridge is connected to an AC power supply and generates a first DC bus voltage according to the AC voltage;

[0031] A signal receiving module receives a dimming control signal sent externally;

[0032] A control module connected to the signal receiving module to obtain a dimming control signal, and obtain dimming data according to the dimming control signal;

[0033] a carrier signal generator connected to the control module to obtain dimming data and generate a corresponding data signal according to the dimming data; and

[0034] A power transmission module is connected to the carrier signal generator to obtain the data signal, and is connected between the first DC output terminal and the second DC output terminal of the first rectifier bridge to change the load impedance of the first rectifier bridge according to the data signal.

[0035] Optionally, the dimming module also includes a power supply module, wherein the power supply module is connected between the first DC output terminal and the second DC output terminal of the first rectifier bridge, and uses the first DC bus voltage output by the first rectifier bridge to generate an internal power supply voltage of the dimming module.

[0036] Optionally, the dimming module further includes a power supply module and a diode, wherein the diode performs half-wave rectification on the AC voltage, the power supply module is connected to the diode, and the internal power supply voltage of the dimming module is generated using the first DC bus voltage rectified by the diode.

[0037] Optionally, the bypass module includes:

[0038] a second rectifier bridge, wherein an AC input end of the second rectifier bridge is connected to the AC power supply and generates a second DC bus voltage according to the AC voltage;

[0039] A zero-crossing detection module, connected to the first DC output terminal of the second rectifier bridge, and used to detect the zero-crossing moment of the second DC bus voltage;

[0040] A data sampling module, connected to the first DC output terminal of the second rectifier bridge, for obtaining a sampling signal of the second DC bus voltage;

[0041] a first micro control unit connected to the zero-crossing detection module and the data sampling module, configured to obtain the waveform of the carrier signal according to the sampling signal, and generate a switch control signal corresponding to the signal modulation of the carrier signal; and

[0042] an impedance module, connected to the first microcontroller unit to receive the switch control signal, and connected between the first DC output terminal and the second DC output terminal of the second rectifier bridge, and changing the load impedance of the first rectifier bridge according to the switch control signal,

[0043] Wherein, the AC input end of the first rectifier bridge and the AC input end of the second rectifier bridge are connected to the same power supply line of the AC power supply.

[0044] Optionally, the plurality of LED driving circuits respectively include:

[0045] a third rectifier bridge, wherein an AC input terminal of the third rectifier bridge is connected in parallel with an AC input terminal of the second rectifier bridge, and generates a third DC bus voltage according to the carrier signal;

[0046] A data sampling module, connected to the first DC output terminal of the third rectifier bridge, for obtaining a sampling signal of the third DC bus voltage;

[0047] a second micro control unit, connected to the data sampling module, for obtaining the waveform of the carrier signal according to the sampling signal, and demodulating the carrier signal to obtain a dimming signal; and

[0048] A power conversion module is connected to the second micro control unit to obtain the dimming signal, and is connected to the DC output end of the third rectifier bridge to obtain electrical energy.

[0049] The power conversion module controls the driving current and / or duty cycle provided to the LED lamp according to the dimming signal, thereby realizing dimming control.

[0050] Optionally, the power conversion module includes a switching power supply adopting any one of a buck topology, a buck-boost topology, and a reverse topology.

[0051] According to another aspect of the present invention, there is provided an LED dimming control method, comprising:

[0052] receiving a dimming control signal;

[0053] Obtaining dimming data from the dimming control signal;

[0054] Obtaining a carrier signal according to the dimming data;

[0055] Obtaining electric energy and dimming signals according to the carrier signal; and

[0056] Controlling the power transmission according to the dimming signal to achieve dimming,

[0057] In the step of obtaining the carrier signal, the first load impedance and the second load impedance that match each other are controlled so as to modulate the AC voltage to generate the carrier signal, and the first load impedance and the second load impedance form a power carrier loop.

[0058] Optionally, the first load impedance and the second load impedance are respectively the load impedance of a first rectifier bridge and the load impedance of a second rectifier bridge.

[0059] Optionally, the first load impedance periodically exhibits high impedance compared to the second load impedance, thereby forming a power carrier loop.

[0060] Optionally, the first rectifier bridge is used to generate an internal power supply voltage.

[0061] Optionally, a diode is used to half-wave rectify the AC voltage to generate the internal supply voltage.

[0062] According to the LED dimmer of the embodiment of the present invention, a signal receiving module is integrated in the dimming module of the LED dimmer, so that the dimming control signal can be converted into a carrier signal and transmitted to the packaged chips of multiple LED bulbs. The packaged chip in the LED bulb can omit the signal receiving module to avoid the interference of the outer shell on the dimming control signal, thereby improving the anti-interference ability. The LED dimmer is also integrated with a bypass module, and the load impedances of the dimming module and the bypass module are matched with each other to form a power carrier loop. The LED driving circuit in the packaged chip of the LED bulb is connected in parallel with the bypass module of the dimmer to obtain a carrier signal, and further obtain electric energy and a dimming signal. Integrating the bypass module in the dimmer can simplify the circuit structure and volume of the LED driving circuit packaged in the LED bulb, so that it is suitable for packaging into a small-sized LED bulb.

[0063] Furthermore, the dimming module of the LED dimmer integrates a power supply module and a diode connected between the power supply module and the AC input end. The power supply module can be directly powered by the voltage after half-wave rectification by the diode, thereby improving the power energy and load capacity of the power supply module. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0065] Figure 1 A schematic block diagram of an LED dimming system according to the prior art is shown.

[0066] Figure 2 A schematic block diagram of an LED dimming system according to a first embodiment of the present invention is shown.

[0067] Figure 3 FIG. 4 is a voltage waveform diagram of an LED dimming system according to a first embodiment of the present invention.

[0068] Figure 4 A detailed block diagram of an LED dimming system according to a first embodiment of the present invention is shown.

[0069] Figure 5 A specific block diagram of a power transmission and carrier signal generator module in a dimming module according to a first embodiment of the present invention is shown.

[0070] Figure 6 A specific block diagram of an impedance module in a bypass module according to a first embodiment of the present invention is shown.

[0071] Figure 7 The voltage waveform diagram in the dimming module and the bypass module according to the first embodiment of the present invention is shown.

[0072] Figure 8A schematic block diagram of an LED dimming system according to a second embodiment of the present invention is shown.

[0073] Fig. 9 A detailed block diagram of an LED dimming system according to a second embodiment of the present invention is shown.

[0074] Fig.10 FIG. 4 is a voltage waveform diagram of a power supply module of an LED dimming system according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0075] The present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements are represented by similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale. In addition, some well-known parts may not be shown.

[0076] Many specific details of the present invention are described below, such as device structure, materials, dimensions, processing technology and techniques, so as to more clearly understand the present invention. However, as those skilled in the art will appreciate, the present invention may be implemented without following these specific details.

[0077] The present invention may be embodied in various forms, some examples of which will be described below.

[0078] Figure 1 1 is a schematic block diagram of an LED dimming system according to the prior art. The LED dimming system 100 includes a switch SW and an LED driving circuit 120. The switch SW is connected between an alternating current power source AC and the LED driving circuit 120, and is used to control the power supply of the LED driving circuit 120, thereby lighting or extinguishing the LED lamp 150.

[0079] The LED driving circuit 120 includes a rectifier bridge 121, a power supply module 122, a signal receiving module 123 and a power conversion module 124. The AC input end of the rectifier bridge 121 is connected to the AC power supply AC via a switch, and the DC output end is connected to the power supply module 122. The rectifier bridge 121 rectifies the AC input voltage into a DC bus voltage. The power supply module 122 smoothes and filters the DC bus voltage to generate an internal power supply voltage. The signal receiving module 123 operates with the internal power supply voltage and converts the dimming control signal sent by an external control device (such as a mobile phone) into a dimming signal. The input end of the power conversion module 124 receives the DC bus voltage, and the output end provides the driving current of the LED lamp.

[0080] During operation, the power conversion module 124 controls the driving current and / or the duty cycle of the LED driving circuit 120 according to the dimming signal, thereby achieving dimming control.

[0081] In the above-mentioned existing LED dimming system, multiple LED bulbs of the same lighting device respectively include an LED driving circuit 120 and an LED lamp 150 encapsulated in a housing. The LED driving circuit 120 has an embedded signal receiving module 123, which converts the received dimming control signal into a dimming signal, thereby controlling the driving current and / or duty cycle of the power conversion module. However, the signal receiving module encapsulated in the LED bulb causes the LED driving circuit 120 to be too large and easily interfered.

[0082] Figure 2 1 is a schematic block diagram of an LED dimming system according to a first embodiment of the present invention. The LED dimming system 200 includes a switch SW, a dimmer 210, and a plurality of LED driving circuits 220. The switch SW is connected between an AC power source AC and the dimmer 210, and is used to control the power supply of the dimmer 210 and the plurality of LED driving circuits 220, so as to light up or extinguish the LED lamp 250.

[0083] The AC power source AC provides an AC voltage via a first power supply line and a second power supply line. The switch SW is connected to the first power supply line.

[0084] The dimmer 210 includes a dimming module 211 and a bypass module 212. The dimming module 211 is connected to any power supply line, and is used to receive a dimming control signal sent by an external control device (such as a mobile phone), and convert the dimming control signal into a carrier signal. The bypass module 212 is connected between the first power supply line and the output end of the dimming module 211, and generates a corresponding bypass impedance according to the working stage of the dimming module 211, thereby maintaining the carrier signal.

[0085] The plurality of LED driving circuits 220 are connected between the first power supply line and the output end of the dimming module 211. The plurality of LED driving circuits 220 provide driving currents for corresponding LED lamps 250 respectively, and demodulate dimming signals from carrier signals.

[0086] During operation, the plurality of LED driving circuits 220 control the driving current and / or the duty cycle according to the dimming signal, thereby achieving dimming control.

[0087] Figure 3 The voltage waveform diagram of the LED dimming system according to the first embodiment of the present invention is shown, and the AC voltage provided by the AC power supply AC is a sine wave voltage. According to the working state of the circuit, the working mode of the LED dimming system 200 can be divided into three stages. As shown in the figure, the first stage of the LED dimming system 200 corresponds to t0 to t1 in the figure, the second stage corresponds to t1 to t2 in the figure, and the third stage corresponds to t2 to t3 in the figure. The time period from t0 to t3 is half a cycle of the sine wave. In this time period, the waveform of the sine wave is a waveform greater than 0.

[0088] During the time period from t0 to t1 of the first stage, the sinusoidal wave voltage starts to rise from zero. At this time, the impedance matching of the bypass module 212 and the dimming module 211 in the circuit allows the sinusoidal wave voltage to be basically at both ends of the dimming module 211, which is used to power the dimming module 211. Therefore, the first stage can also be called the power supply stage.

[0089] In the power supply stage, the bypass module 212 has a low impedance relative to the dimming module 211 , the sine wave voltage is almost entirely in the dimming module 211 , and there is no voltage across the bypass module 212 .

[0090] Between time t0 and t1, the current in the circuit forms a loop through the AC power source AC, the switch SW, the bypass module 212, and the dimming module 211. In the second stage, during the time period from t1 to t2, the sine wave voltage continues to rise, and begins to decline after reaching the peak value. At this time, the impedance matching of the bypass module 212 and the dimming module 211 in the circuit allows the sine wave voltage to be basically at both ends of the bypass 212, which is used to transmit power to the LED driving circuit 220. Therefore, the second stage can also be called the power transmission stage.

[0091] In the power transmission stage, the bypass module 212 is high impedance relative to the dimming module 211 , and the sine wave voltage is almost entirely in the bypass module 212 , and there is no voltage across the dimming module 211 .

[0092] Between time t1 and t2, the current in the circuit forms a loop through the AC power supply AC, the switch SW, the LED driving circuit 220, and the dimming module 211. At this time, the LED driving circuit 220 and the bypass module 212 work in parallel, and the bypass module 212 is in a high-impedance state.

[0093] In the third stage, during the time period from t2 to t3, the sine wave voltage continues to drop until it drops to 0. At this time, the impedance matching of the bypass module 212 and the dimming module 211 in the circuit causes the sine wave voltage at both ends of the bypass module 212 to carry dimming data, which is used to provide a dimming signal for the LED driving circuit 220. Therefore, the third stage can also be called a data stage.

[0094] Between t2 and t3, the current in the dimming system forms a loop through the AC power source AC, the switch SW, the bypass module 212, and the dimming module 211. At this time, the LED driving circuit 220 and the bypass module 212 work in parallel.

[0095] Figure 4 A detailed block diagram of an LED dimming system according to a first embodiment of the present invention is shown. Figure 5 A specific block diagram of a power transmission and carrier signal generator module in a dimming module according to a first embodiment of the present invention is shown. Figure 6A specific block diagram of an impedance module in a bypass module according to a first embodiment of the present invention is shown.

[0096] In this embodiment, the dimming module 211, the bypass module 212, and the switch SW are connected in series between two output terminals of the alternating current power source AC.

[0097] The dimmer 210 includes a dimming module 211 and a bypass module 212. The dimming module 211 includes a rectifier bridge 2111, a power transmission module 2112, a signal receiving module 2113, a control module 2114, a carrier signal generator 2115, and a power supply module 2116. The bypass module 212 includes a rectifier bridge 2121, an impedance module 2122, a zero-crossing detection module 2123, a data sampling module 2124, and a microcontroller 2125.

[0098] like Figure 4 As shown, the rectifier bridge 2111 of the dimming module 211, the rectifier bridge 2121 of the bypass module 212 and the switch SW are connected in series between two power supply terminals of the alternating current power source AC.

[0099] In the dimming module 211, the rectifier bridge 2111 rectifies the AC voltage into a DC bus voltage. The power transmission module 2112 and the power supply module 2116 are connected in parallel between the positive and negative output terminals of the rectifier bridge 2111. The power supply module 2116 uses the DC voltage output by the rectifier bridge 2111 to generate a power supply voltage, and provides the power supply voltage to the signal receiving module 2113 and the control module 2114.

[0100] The signal receiving module 2113 is, for example, a module such as Bluetooth, ZIGBEE, WIFI, infrared, etc., and its main function is to receive a dimming control signal sent by an external control device (such as a mobile phone). The control module 2114 decodes the dimming control signal to obtain dimming data, and controls the operation of the power transmission module 2112 and the carrier signal generator 2115 according to the dimming data.

[0101] The power transmission module 2112 can switch between a high impedance state and a low impedance state. Figure 5As shown, the power transmission module 2112 includes a transistor Q1 and a resistor R1. By controlling the voltage or current at the control end of the transistor Q1, the transistor Q1 is placed in saturation conduction or linear conduction, thereby controlling the load impedance of the rectifier bridge 2111. The carrier signal generator 2115 includes a transistor Q2, a voltage regulator Z1 and a diode D1 connected in series, and is used to generate a square wave signal with a fixed frequency. The control module 2114 obtains a data signal according to the level state of the square wave signal generated by the carrier signal generator 2115. For example, in each clock cycle of the square wave signal, the level state of the square wave signal is controlled according to the numerical value of the corresponding data bit, thereby converting the dimming data into a data signal of a change sequence of the corresponding level state, and superimposing the data signal on the AC voltage. Further, the data signal is used to control the switch state in the power transmission module 2112, and a change sequence of the impedance state of the power transmission module 2112 is obtained in multiple clock cycles, so that the signal is modulated in at least a part of the time period of the half-power frequency cycle of the AC voltage to obtain a carrier signal.

[0102] In the bypass module 212, the rectifier bridge 2121 rectifies the AC voltage into a DC bus voltage. The rectifier bridge 2111 and the AC input terminal of the rectifier bridge 2121 are connected in series on the same power supply line. The impedance module 2122 is connected between the positive and negative output terminals of the rectifier bridge 2121. For example, Figure 6 As shown, the impedance module 2122 includes a switch tube Q3 and a resistor R2 connected in series, and also includes a switch SW2 connected in parallel with the resistor R2. The impedance module 2122 controls the load impedance of the rectifier bridge 2121 by changing the switching state of the switch tube Q3.

[0103] The zero-crossing detection module 2123 and the data sampling module 2124 are respectively connected to the positive output terminal of the rectifier bridge 2121 to obtain the zero-crossing moment and the sampling signal of the DC bus voltage respectively. The bypass module 212 also includes a microcontroller unit (MCU) 2125. The microcontroller unit 2125 obtains the waveform of the carrier signal according to the sampling signal, and generates a switch control signal corresponding to the signal modulation of the carrier signal, thereby controlling the switch tube Q3 in the impedance module 2122.

[0104] In the dimmer 210 , at least during the signal modulation period, the load impedance of the rectifier bridge 2111 of the dimming module 211 matches the load impedance of the rectifier bridge 2121 in the bypass module 212 , thereby forming a power carrier loop.

[0105] For example, in order to transmit the data value "0", in one clock cycle, the power transmission module 2112 is in a low impedance state relative to the impedance module 2122, so that there is substantially no voltage drop on the rectifier bridge 2111 of the dimming module 211, and the rectifier bridge 2121 of the bypass module 212 bears substantially all the voltage drop, thereby transmitting the complete waveform of the AC voltage to the multiple LED driving circuits 250. In order to transmit the data value "1", in one clock cycle, the power transmission module 2112 is in a high impedance state relative to the impedance module 2122, so that there is substantially all the voltage drop on the rectifier bridge 2111 of the dimming module 211, and there is substantially no voltage drop on the rectifier bridge 2121 of the bypass module 212, thereby transmitting the missing-phase AC voltage waveform to the multiple LED driving circuits 250.

[0106] In this embodiment, a plurality of LED driving circuits 220 are connected in parallel with the bypass module 212 .

[0107] The LED driving circuit 220 includes a rectifier bridge 2211, a data sampling module 2212, a microcontroller unit (MCU) 2213 and a power conversion module 2214. The two AC input terminals of the rectifier bridge 2211 are respectively connected to the two AC input terminals of the rectifier bridge 2121. The rectifier bridge 2211 rectifies the AC input voltage into a DC bus voltage. The data sampling module 2122 is connected to the positive output terminal of the rectifier bridge 2211 to obtain a sampling signal of the DC bus voltage. The microcontroller unit 2123 obtains the waveform of the carrier signal according to the sampling signal, demodulates the dimming data from the carrier signal, and generates a corresponding dimming signal to further control the power conversion module 2214.

[0108] In the LED driving circuit 220, the input end of the power conversion module 2214 is connected to the positive and negative output ends of the rectifier bridge 2211. The output end of the power conversion module 2214 is used to supply power to a load lamp (e.g., an LED lamp). The micro control unit 2123 provides a dimming signal to the power conversion module 2214. The power conversion module 2214 controls the driving current and / or duty cycle provided to the LED lamp 250 according to the dimming signal, thereby realizing dimming control.

[0109] The power conversion module 2214 can be implemented by a switching power supply or a linear constant current control circuit, etc. For example, the power conversion module 2214 can be implemented by a switching power supply of various topologies such as a buck topology, a buck-boost topology, and a flyback topology.

[0110] Figure 7 FIG. 4 shows a voltage waveform diagram in the dimming module and the bypass module according to the first embodiment of the present invention. Figure 5 and Figure 6 As shown, V1 is the control signal of the switch tube Q1, V2 is used to control the switch tube Q2, V3 is the control signal of the switch tube Q3, and V4 is the control signal of the switch SW2.

[0111] like Figure 7 As shown, in the dimming module 211, when the control signal V2 is at a high level, the transistor Q1 is fully turned on through the driving resistor R1 in the power transmission module 2112, and the voltage is fully transmitted to both ends of the bypass module 212 circuit. When the control signal V2 is at a low level, the impedance of the transistor Q1 is determined by the carrier signal generator 2115.

[0112] When the control signal V2 is at a low level and V1 is at a high level, the voltage V across the rectifier bridge 2111 in the dimming module 211 is 调光 The voltage of the gate of transistor Q1 in power transmission module 2112 will rise until it breaks down diode D1, voltage regulator Z1 and transistor Q2 in carrier signal generator 2115. The voltage of the gate of transistor Q1 in power transmission module 2112 will rise and finally stabilize at Miller platform. Current flows through drain D and source S of transistor Q1 and forms a loop through bypass module 212. Therefore, voltage V 调光 =Vd1+Vz1+Vds2+Vgs1, where Vd1 is the forward voltage drop of diode D1, Vz1 is the breakdown voltage of voltage regulator Z1, Vds2 is the voltage across the D and S poles of transistor Q2, and Vgs1 is the voltage across the G and S poles of transistor Q1. The loop path includes AC source AC, rectifier bridge 2111, diode D1, voltage regulator Z1, transistor Q2, transistor Q1, rectifier bridge 2121, transistor Q3, and resistor R2.

[0113] In the bypass module 212, when the voltage V3 is at a high level and V4 is at a low level, the current I of the transistor Q3 in the impedance module 2122 is (V3-Vgs3) / R2, wherein Vgs3 is the voltage between the G pole and the S pole of the transistor Q3. When the voltage V4 is at a high level, the transistor Q3 is fully turned on, and the current size is determined by the dimming module 211.

[0114] Figure 8 A schematic block diagram of an LED dimming system according to a second embodiment of the present invention is shown. The main difference between the LED dimming system according to the second embodiment and the first embodiment is that the dimming module 211 includes a diode D2, so that the power supply module 2116 can be independently powered by the diode D2, and the anode of the diode D2 is directly connected to any end of the AC power supply, so that the LED dimming system is more optimized in terms of power supply.

[0115] Fig. 9Detailed block diagram of the LED dimming system according to the second embodiment of the present invention is shown. The main difference between the LED dimming system of the second embodiment and the first embodiment is that the dimming module 211 includes a diode D2, so that the power supply module 2116 can be independently powered by the diode D2. The following only describes the differences between the first embodiment and the second embodiment, and the similarities are not described in detail.

[0116] The anode of the diode D2 is connected to one end of the AC power source AC, and the cathode is connected to the high potential input end of the power supply module 2116. Further, the low potential end of the power supply module 2116 is grounded. After the AC voltage of the AC power source AC is half-wave rectified by the diode D2, the power supply module 2116 is provided with electric energy to further generate the internal power supply voltage. For example, when the voltage at the second output end of the AC source AC is higher than that at the first output end, the AC voltage provides electric energy to the power supply module 2116 through the diode D2. This electric energy is much higher than the voltage at both ends of the dimming module 211 in the dimming system according to the first embodiment, so that the load capacity of the power supply module 2116 becomes stronger.

[0117] Fig.10 The voltage waveform of the power supply module of the LED dimming system according to the second embodiment of the present invention is shown in the figure. The voltage across the power supply module 2116 is shown in the figure. The current in the circuit passes through the AC power supply AC, the diode D2, the power supply module 2116, and the rectifier bridge 2111 to form a loop, forming a half-wave rectifier circuit. Because the transistor Q1 is turned on most of the time, when it is turned on, from the inside of the dimming module 2111, the voltage V 调光 The potential of the other end of the AC power source AC is basically the same as that of one end of the AC power source AC directly connected to the rectifier bridge 2111, so that the other end of the AC power source AC can provide energy to the power supply module 2116 through the diode D2.

[0118] The embodiments of the present invention are as described above, and these embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. The scope of protection of the present invention shall be based on the scope defined by the claims of the present invention.

Claims

1. An LED dimmer, comprising: A dimming module and a bypass module connected in series between the first and second AC input terminals, The dimming module receives a dimming control signal and obtains dimming data from the dimming control signal. The load impedances of the dimming module and the bypass module match each other to form a power carrier loop, thereby superimposing the dimming data on the AC voltage to generate a carrier signal. The dimming module comprises a first rectifier bridge, wherein an AC input end of the first rectifier bridge is connected to an AC power supply, and a first DC bus voltage is generated according to the AC voltage; The bypass module comprises: a second rectifier bridge, wherein an AC input end of the second rectifier bridge is connected to the AC power supply and generates a second DC bus voltage according to the AC voltage; a data sampling module, connected to the first DC output terminal of the second rectifier bridge, and used to obtain a sampling signal of the second DC bus voltage; a first micro control unit, connected to the data sampling module, for obtaining the waveform of the carrier signal according to the sampling signal, and generating a switch control signal corresponding to the signal modulation of the carrier signal; and an impedance module, connected to the first micro control unit to receive the switch control signal, and connected between the first DC output terminal and the second DC output terminal of the second rectifier bridge, and changing the load impedance of the second rectifier bridge according to the switch control signal; The AC input end of the first rectifier bridge and the AC input end of the second rectifier bridge are connected to the same power supply line of the AC power supply.

2. The LED dimmer according to claim 1, wherein: The dimming module comprises: A signal receiving module, receiving a dimming control signal sent externally; A control module connected to the signal receiving module to obtain a dimming control signal, and obtain dimming data according to the dimming control signal; a carrier signal generator connected to the control module to obtain dimming data and generate a corresponding data signal according to the dimming data; and A power transmission module is connected to the carrier signal generator to obtain the data signal, and is connected between the first DC output terminal and the second DC output terminal of the first rectifier bridge to change the load impedance of the first rectifier bridge according to the data signal.

3. The LED dimmer according to claim 2, wherein the dimming module further comprises a power supply module, wherein: The power supply module is connected between the first DC output terminal and the second DC output terminal of the first rectifier bridge, and uses the first DC bus voltage output by the first rectifier bridge to generate an internal power supply voltage of the dimming module.

4. The LED dimmer according to claim 2, wherein: The bypass module comprises: A zero-crossing detection module, connected to the first DC output terminal of the second rectifier bridge, and used to detect the zero-crossing moment of the second DC bus voltage; The first micro control unit is connected to the zero-crossing detection module.

5. An LED dimming system, comprising: An LED dimmer, the LED dimmer comprising a dimming module and a bypass module connected in series between a first and a second AC input terminal; A plurality of LED driving circuits are connected in parallel with the bypass module of the LED dimmer, The dimming module receives a dimming control signal and obtains dimming data from the dimming control signal. The load impedances of the dimming module and the bypass module match each other, so that the dimming data is superimposed on the AC voltage to generate a carrier signal. The plurality of LED driving circuits receive carrier signals respectively, obtain power and dimming signals according to the carrier signals, and control power transmission according to the dimming signals to achieve dimming. The dimming module comprises a first rectifier bridge, wherein an AC input end of the first rectifier bridge is connected to an AC power supply, and a first DC bus voltage is generated according to the AC voltage; The bypass module comprises: a second rectifier bridge, wherein an AC input end of the second rectifier bridge is connected to the AC power supply and generates a second DC bus voltage according to the AC voltage; a data sampling module, connected to the first DC output terminal of the second rectifier bridge, and used to obtain a sampling signal of the second DC bus voltage; a first micro control unit, connected to the data sampling module, for obtaining the waveform of the carrier signal according to the sampling signal, and generating a switch control signal corresponding to the signal modulation of the carrier signal; and an impedance module, connected to the first micro control unit to receive the switch control signal, and connected between the first DC output terminal and the second DC output terminal of the second rectifier bridge, and changing the load impedance of the second rectifier bridge according to the switch control signal; The AC input end of the first rectifier bridge and the AC input end of the second rectifier bridge are connected to the same power supply line of the AC power supply.

6. The LED dimming system according to claim 5, wherein: The dimming module comprises: A signal receiving module, receiving a dimming control signal sent externally; A control module connected to the signal receiving module to obtain a dimming control signal, and obtain dimming data according to the dimming control signal; a carrier signal generator connected to the control module to obtain dimming data and generate a corresponding data signal according to the dimming data; and A power transmission module is connected to the carrier signal generator to obtain the data signal, and is connected between the first DC output terminal and the second DC output terminal of the first rectifier bridge to change the load impedance of the first rectifier bridge according to the data signal.

7. The LED dimming system according to claim 6, wherein the dimming module further comprises a power supply module, wherein: The power supply module is connected between the first DC output terminal and the second DC output terminal of the first rectifier bridge, and uses the first DC bus voltage output by the first rectifier bridge to generate an internal power supply voltage of the dimming module.

8. The LED dimming system according to claim 6, wherein: The bypass module comprises: A zero-crossing detection module, connected to the first DC output terminal of the second rectifier bridge, and used to detect the zero-crossing moment of the second DC bus voltage; The first micro control unit is connected to the zero-crossing detection module.

9. The LED dimming system according to claim 6, wherein: The plurality of LED driving circuits respectively include: a third rectifier bridge, wherein an AC input terminal of the third rectifier bridge is connected in parallel with an AC input terminal of the second rectifier bridge, and generates a third DC bus voltage according to the carrier signal; A data sampling module, connected to the first DC output terminal of the third rectifier bridge, for obtaining a sampling signal of the third DC bus voltage; a second micro control unit, connected to the data sampling module, for obtaining the waveform of the carrier signal according to the sampling signal, and demodulating the carrier signal to obtain a dimming signal; and A power conversion module is connected to the second micro control unit to obtain the dimming signal, and is connected to the DC output end of the third rectifier bridge to obtain electrical energy. The power conversion module controls the driving current and / or duty cycle provided to the LED lamp according to the dimming signal, thereby realizing dimming control.

10. The LED dimming system according to claim 9, wherein: The power conversion module includes a switching power supply adopting any one of a buck topology, a buck-boost topology, and a reverse topology.

11. An LED dimming control method, applicable to the dimmer according to any one of claims 1 to 4, the LED dimming control method comprising: receiving a dimming control signal; Obtaining dimming data from the dimming control signal; Obtaining a carrier signal according to the dimming data; Obtaining electric energy and dimming signals according to the carrier signal; as well as Controlling power transmission according to the dimming signal to achieve dimming, In the step of obtaining the carrier signal, the first load impedance and the second load impedance that match each other are controlled so as to modulate the AC voltage to generate the carrier signal, and the first load impedance and the second load impedance form a power carrier loop.

12. The control method according to claim 11, wherein: The first load impedance and the second load impedance are respectively the load impedance of the first rectifier bridge and the load impedance of the second rectifier bridge.

13. The control method according to claim 11, wherein: The first load impedance periodically exhibits high impedance compared to the second load impedance, thereby forming a power carrier loop.

14. The control method according to claim 12, wherein: The first rectifier bridge is used to generate an internal power supply voltage.

15. The control method according to claim 12, wherein: The internal supply voltage is generated by half-wave rectification of the AC voltage using a diode.

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