TW201521513A - TRIAC dimming controller - Google Patents

Abstract

A TRIAC dimming controller, which is a single-stage power factor correction circuit structure, receives an input voltage through a conversion module having a controllable current source and generates a working current that drives an LED light source to emit light. A chip-type control module is used to monitor a change in the input voltage so that a mechanism of a switching unit inside a fixed-frequency switching chip is used to make the working current change in accordance with a sine wave of the input voltage based on a reference peak to improve the PF effect of the entire circuit. Moreover, when a duty cycle of the switching unit reaches the maximum tolerance, an actuation state of the switching unit is switched to eliminate an audio phenomenon generated as the TRIAC dimming controller performs a low-frequency energy conversion, preventing lightings or other electrical devices from making noises during operation. As a result, use quality can be improved.

Description

TRIAC dimming controller

The invention belongs to the technical field of electric light source driving circuits, in particular to a TRIAC dimming controller, which is generated by phase-cutting of a TRIAC (Tri-Electrode AC Switch) through a controllable current source compensation TRIAC (Tri-Electrode AC Switch) The instability phenomenon, the power factor (PF) correction effect.

It is generally known that LED (Light Emitting Diode) lamps use control circuits that use phase-controlled switching elements such as SCR (Silicon Controlled Rectifier) or TRIAC to change the voltage phase of the input power supply. The size of the driving power outputted by the control circuit is changed by changing the conduction angle of the voltage phase, thereby adjusting the amount of driving current flowing into the LED light source to achieve a dimming effect. However, although such a dimming setting has the advantages of simple control and easy installation, the input power supply voltage waveform will be in a distorted state, causing problems such as PF drop and voltage harmonic increase. Moreover, according to the current/voltage (I/V) characteristic curve of the LED, the LED and the nonlinear component, that is, the ratio of the voltage to the current is not proportional, therefore, the dimming method will change the driving voltage and the driving current. Inconsistent, making the dimming effect inaccurate and causing virtual power consumption. Furthermore, due to the component characteristics of the TRIAC, if the operating voltage flowing into the control circuit is too low and the current flowing through the TRIAC is insufficient for the required operating current, the TRIAC will repeatedly switch to the operating state, resulting in no driving current. Continuously flashes the LED, which reduces the quality of the illumination.

In order to solve the above problem, the LED lamp 1 having a dimmer 10 can be additionally provided with a compensation circuit 12 adjacent to a control circuit 11 as shown in FIG. 1. The compensation circuit 12 is mainly composed of a reference voltage generator 120. a voltage sampler 121, a comparator 122 and a control switch The comparator 122 is configured to compare a reference voltage generated by the reference voltage generator 120 with a sampling voltage formed by the voltage sampler 121, and output a control voltage when the sampling voltage is lower than the reference voltage. The control switch 123 is configured to form a loop between the compensation circuit 12 and the control circuit 11 and provide a holding current to the control circuit 11 through the control switch 123 for ensuring the operational stability of the dimmer 10 and avoiding the LED luminaire 1 has problems such as stroboscopic occurrence. The compensation circuit 12, which is additionally added, can stabilize the working quality of the dimmer 10, but at the same time, it has a certain power loss and seriously affects the overall efficiency of the system.

In view of this, how to eliminate the need to additionally add the compensation circuit 12, The PF improvement and the TRIAC current support function of the control circuit 11 are realized by the simplest controllable current source, so as to stabilize the TRIAC dimming effect and improve the power conversion efficiency of the overall circuit, thereby improving the working quality and stability of the LED lamp 1, that is, It is the subject of inquiry for the present invention.

In view of the problems of the prior art, it is an object of the present invention to provide a device The TRIAC dimming controller that controls the current source to instantly sense and ensure that the operating current output by the controllable current source changes with the input voltage sine wave and is greater than the basic working voltage required by the TRIAC component to ensure dimming. Accuracy and improve the efficiency of the overall circuit.

According to the purpose of the present invention, the TRIAC dimming controller is a single stage power factor The modulating circuit structure is provided with a dimming module, a rectifying module, a converting module and a control module. The dimming module has a TRIAC component, and the rectifying module is electrically connected to the dimming module and the a conversion module, wherein the conversion module is electrically connected to the control module and the plurality of LED light sources to drive the LED light sources to emit light, so as to ensure the working stability of the dimming module and improve the power factor of the overall circuit. The control module is configured to receive a stable operating current by using a controllable current source to receive an input voltage of the rectifier module output; the control module is provided with a peak detecting unit, a frequency switching unit, and a a duty cycle control unit (Duty Cycle Control Unit) and a switch unit electrically connected to the controllable current source, the peak detection unit being electrically connected to the switch unit and configured to detect the peak value of the operating current a detection signal; the fixed frequency switching unit is electrically connected to the responsibility cycle control unit and the switch unit for a predetermined frequency Rate periodically outputting a switching signal; the responsibility cycle control unit is electrically connected to the switch unit for calculating the preset frequency to obtain a cycle, and analyzing the cycle to output a control signal when the working time of the cycle reaches a maximum tolerance The switch unit adjusts the actuation state according to the received detection signal, the control signal or the switching signal, and changes the amount of time that the controllable current source outputs the operating current to the LED light sources to adjust the output current amount, and ensures the The operating current is greater than the holding current required for operation of the TRIAC component when the TRIAC component is turned on.

Wherein, the control module is a control chip, and the peak detecting unit is a comparison The frequency switching unit is a frequency generator, and the switch unit is mainly composed of an NAND gate, an RS flip flop and an N Type Metal Oxide Semiconductor Field Effect Transistor (N- The MOSFET is configured; the positive input end of the comparator is coupled to the source of the N-MOSFET, the negative input terminal is connected to a reference peak, and the output terminal is coupled to one of the input terminals of the OR gate, and the gate is coupled to another An input end is coupled to the responsibility cycle control unit; the set end of the RS flip-flop is coupled to the output of the frequency generator and the responsibility cycle control unit, and the reset end is coupled to the output of the OR gate, and the output thereof The terminal is coupled to the gate of the N-MOSFET, and the drain of the N-MOSFET is coupled to the output of the controllable current source. The conversion module is provided with an anti-backflow component and a filter component. The anti-backflow component is coupled to the output end of the controllable current source, and the other end is coupled to the filter component and the LED light sources. The anti-backflow component is a diode, and the filter component is a capacitor, and the controllable current source is an inductor.

And the OR gate is configured to receive at least the detection signal and the control signal In one case, a reset signal is output to the RS flip-flop, and the RS flip-flop is driven to adjust the N-type metal oxide half-field effect transistor to change the magnitude of the operating current output by the controllable current source.

In summary, the present invention senses the input power by using the wafer type control module. After the change of the voltage, under a reference peak, the operating current is switched with the sine wave waveform of the input voltage to increase the PF of the overall circuit by using a fixed frequency switching manner of the N-MOSFET, and is used in the duty cycle. The on-time reaches the maximum tolerance. For example, when the Duty Cycle=50% switches the N-MOSFET active state, the audio phenomenon generated by the TRIAC dimming controller for low-frequency energy conversion is eliminated to avoid the luminaire or other electronic device. At the time of work, a noise such as "嗡~" is issued, which seriously affects the quality of use.

Traditional skill

1‧‧‧LED lamps

10‧‧‧Dimmer

11‧‧‧Control circuit

12‧‧‧Compensation circuit

120‧‧‧reference voltage generator

121‧‧‧Voltage Sampler

122‧‧‧ comparator

123‧‧‧Control switch

this invention

2‧‧‧TRIAC dimming controller

20‧‧‧ dimming module

200‧‧‧TRIAC components

21‧‧‧Rectifier Module

22‧‧‧Transition module

220‧‧‧Controllable current source

221‧‧‧Anti-backflow element

222‧‧‧Filter components

23‧‧‧Control Module

230‧‧‧Voltage generator

231‧‧‧peak detection unit

2310‧‧‧Detection resistance

232‧‧‧Frequency switching unit

233‧‧‧Responsibility Cycle Control Unit

234‧‧‧Switch unit

2340‧‧‧ or gate

2341‧‧‧RS forward and reverse

2342‧‧‧ drive

2343‧‧‧N-MOSFET

3‧‧‧LED light source

Figure 1 is a schematic diagram of a circuit for holding a current compensation circuit in a conventional LED lamp.

Figure 2 is a block diagram of a preferred embodiment of the present invention.

Figure 3 is a circuit diagram showing an embodiment of a preferred embodiment of the present invention.

Figure 4 is a circuit diagram of a second embodiment of the preferred embodiment of the present invention.

Figure 5 is a waveform diagram of a preferred embodiment of the present invention.

In order for your review board to have a clear understanding of the contents of the present invention, please follow the instructions below. Please refer to the map.

2 to 4 are respectively a block diagram of a preferred embodiment of the present invention, a circuit diagram of an embodiment, and a circuit diagram of two embodiments. As shown in the figure, the TRIAC dimming controller 2 is a single-stage power factor correction circuit architecture, and includes a dimming module 20, a rectifying module 21, a converting module 22, and a control module 23, and the switching module The group 22 is electrically connected to an external power source (not shown) through the rectifier module 21 and the dimming module 20, and is electrically connected to the control module 23 and the plurality of LED light sources 3 to intercept the power of the external power source. After the working current (I _O ) is formed, the LED light sources 3 are driven to operate, and at the same time, the working stability of the dimming module 20 is ensured and the power factor of the overall circuit is improved.

The dimming module 20 has a TRIAC component 200 electrically connected to the external power source through the TRIAC component 200. The rectifier unit 21 is a bridge rectifier circuit and its input end is electrically connected to the TRIAC component 200. The conversion module 22 is mainly composed of a controllable current source 220, such as an inductor, a backflow prevention component 221, such as a diode and a filter component 222, such as a capacitor. The TRIAC component 200 adjusts the phase conduction angle of the AC voltage of the external current, and then rectifies the input voltage (V _in ) through the bridge rectifier circuit, and the controllable current source 220 stores the input voltage to form a stable operation. Current. The control module 23 is a control chip having at least 6 pins of VIN, VDD, LX, RT, CS, and GND, and a voltage generator 230, a peak detecting unit 231, and a frequency switching unit 232. A duty cycle control unit 233 and a switch unit 234, and the peak detection unit 231 is a comparator, the frequency switching unit 232 is a frequency generator, and the switch unit 234 can be a gate 2340, an RS positive The inverter 2341, a driver 2342 and an N-MOSFET 2343 are formed. One end of the controllable current source 220 is electrically connected to the output end of the bridge rectifier circuit, the other end is electrically connected to the anode of the anti-backflow component 221, and the LX pin of the control module 23 is electrically connected to the N-MOSFET. The cathode of the anti-backflow element 221 is electrically connected to the filter element 222 and the LED light sources 3. The input end of the voltage generator 230 is electrically connected to the input end of the controllable current source 220 through the VIN pin to intercept the input voltage and convert the working energy required to form the internal circuit of the chip. The positive input end of the comparator is electrically connected to the source of the N-MOSFET 2343 and coupled to one of the external detecting resistors 2310 through the CS pin, the negative input terminal is connected to a reference peak ( _Vpeak ), and the output terminal is coupled. Connected to one of the inputs of the OR gate 2340, and the other input of the OR gate 2340 is coupled to the duty cycle control unit 233. The set terminal (ie, the S input pin) of the RS flip-flop 2341 is coupled to the output of the frequency generator and the duty cycle control unit 233, and the R input pin of the reset terminal is coupled to the output of the OR gate 2340. The output terminal is electrically connected to the gate of the N-MOSFET 2343 through the driver 2342.

The fixed frequency switching unit 232 periodically outputs a switching signal according to a preset frequency, for example, 65 kHz or 50 kHz, to trigger the RS flip-flop 2341 to adjust the operating state of the N-MOSFET 2343 through the driver 2342 to change the controllable current source. 220 enters the energy storage mode or provides the operating current to the LED light sources 3 through the anti-backflow component 221 and the filter component 222, such that the current (I _L ) in the controllable current source 220 will be as shown in FIG. 5 .

The peak detecting unit 231 receives the operating current output by the controllable current source 220 through the N-MOSFET 2343, and uses the impedance analysis provided by the detecting resistor 2310 to form a detected voltage value to detect the detected value. The peak value of the operating current is used, and the peak detecting unit 231 compares the detected voltage value with the reference peak value to output a detecting signal to the gate 2340, so that the peak value of the working current is greater than the benchmark built in the chip. The gate 2340 receives the detection signal of the high voltage level and outputs a reset signal to the RS flip-flop 2341 to adjust the N-MOSFET 2343 through the driver 2342 to change the controllable current source 220. The size of the operating current output. At the same time, the duty cycle control unit 233 calculates the preset frequency to obtain a cycle, and analyzes the working time of the cycle as a percentage of the cycle, so that the duty time (Duty Cycle) of the cycle reaches a maximum tolerance, for example, 30. %, 60%, 70% or 90% of the time outputs a control signal to the OR gate 2340, and the OR gate 2340 outputs the reset signal to the RS flip-flop 2341 according to the control signal, so that the The driver 2342 adjusts the N-MOSFET 2343 to change the magnitude of the operating current output by the controllable current source 220 such that the peak value of the operating current is not greater than a reference ( _Ipeak ) set by the control module 23. Under the reference, the sine wave of the input voltage changes, and the PF correction effect is realized to improve the working efficiency of the overall circuit.

The above description is only illustrative of preferred embodiments and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

2‧‧‧TRIAC dimming controller

20‧‧‧ dimming module

200‧‧‧TRIAC components

21‧‧‧Rectifier Module

22‧‧‧Transition module

220‧‧‧Controllable current source

23‧‧‧Control Module

231‧‧‧peak detection unit

232‧‧‧Frequency switching unit

233‧‧‧Responsibility Cycle Control Unit

234‧‧‧Switch unit

3‧‧‧LED light source

Claims (6)

A TRIAC dimming controller is a single-stage power factor correction circuit architecture, and includes a dimming module, a rectifying module, a converting module and a control module, the dimming module having a TRIAC component, The rectifier module is electrically connected to the dimming module and the conversion module, and the conversion module is electrically connected to the control module and the plurality of LED light sources to drive the LED light sources to emit light to ensure the dimming module The work stability is improved while improving the power factor of the overall circuit, wherein the conversion module uses a controllable current source to receive one of the output voltages of the rectifier module to form a stable operating current; the control module a peak detecting unit, a frequency switching unit, a duty cycle control unit and a switch unit, the switch unit is electrically connected to the controllable current source, and the peak detecting unit is electrically connected to the switch unit and configured to detect The peak value of the working current is analyzed to form a detection signal; the fixed frequency switching unit is electrically connected to the responsibility cycle control unit and the switch unit for periodically outputting a switching signal at a preset frequency The responsibility cycle control unit is electrically connected to the switch unit for calculating the preset frequency to obtain a cycle, and analyzing the cycle to output a control signal when the working time of the cycle reaches a maximum tolerance; the switch unit receives the control signal; The detection signal, the control signal or the switching signal adjusts an actuation state to change a length of time that the controllable current source outputs the operating current to the LED light sources to adjust an output current amount, and ensures the operating current is in the TRIAC component. The conduction current is greater than the holding current required for the operation of the TRIAC component. The TRIAC dimming controller according to claim 1, wherein the control module is a control chip, and the peak detecting unit is a comparator, and the fixed frequency switching unit is a frequency generator, the switching unit Mainly composed of a gate, an RS flip-flop and an N-type gold-oxygen half-field effect transistor; the positive input end of the comparator is coupled to the source of the N-type gold-oxygen half-effect transistor, and the negative input terminal Connected to a reference peak, and the output end is coupled to one of the input terminals of the OR gate, and the other input end of the OR gate is coupled to the duty cycle control unit; the set end of the RS flip-flop is coupled to the frequency generator The output end and the duty cycle control unit have a reset end coupled to the output end of the OR gate, and an output end coupled to the gate of the N-type metal oxide half field effect transistor And the drain of the N-type metal oxide half field effect transistor is coupled to the output end of the controllable current source. The TRIAC dimming controller of claim 2, wherein the gate is configured to output a reset signal to the RS flip-flop when receiving at least one of the detection signal and the control signal. The RS flip-flop adjusts the N-type MOS field effect transistor to change the magnitude of the operating current output by the controllable current source. The TRIAC dimming controller according to claim 3, wherein the conversion module is provided with an anti-backflow component and a filter component, and one end of the anti-backflow component is coupled to the output end of the controllable current source, and the other end is coupled. The filter element and the LED light sources are connected. The TRIAC dimming controller according to claim 4, wherein the anti-backflow component is a diode, and the filter component is a capacitor. The TRIAC dimming controller of claim 5, wherein the controllable current source is an inductor.