An LED application circuit for enhancing compatibility of triac dimmer

Abstract

The utility model relates to the field of LED lighting provides a kind of LED application circuit of compatibility of thyristor dimmer enhancement, including input voltage and phase detection module, adaptive control circuit, main control module and maintenance current control circuit, the input voltage and phase detection module, the input end of input voltage and phase detection module connects main power supply, the main power supply is the input power supply after AC input through thyristor voltage regulation, rectifier circuit rectification, input end connects the input end of main control module, the input end of adaptive control circuit is connected with the input end of main control module, for the parameter information transmission of thyristor dimmer is given main control module, the controlled end of maintenance current control circuit is connected with the output end of main control module, to generate corresponding maintenance current according to the control signal of main control module;The utility model passes through the input voltage and adaptive control signal of collection, and further stabilizes the maintenance current of thyristor dimmer, guarantees output stability.

Description

Technical Field

[0001] This utility model relates to the field of LED lighting, and more specifically, to an LED application circuit that enhances the compatibility of SCR dimmers. Background Technology

[0002] Currently, SCR dimmers are widely used in the LED lighting field. A typical SCR LED lighting circuit includes a SCR, a rectifier bridge, and an LED driver circuit located on the AC input line. After being triggered, the SCR needs to maintain normal operation, which requires two conditions to be met: excitation current and sustaining current. The sustaining current is approximately 20mA (this varies depending on the dimmer). If these conditions are not met, the SCR will turn off erroneously, resulting in phase distortion and unstable output.

[0003] Traditional SCR power dimming solutions use fixed BLD circuitry (such as...). Figure 1 As shown, when dimming to a smaller phase angle, the power supply current is too low to provide sufficient sustaining current to the dimmer's thyristor, resulting in unstable output, causing the lamp to flicker or turn on intermittently. Utility Model Content

[0004] The problem solved by this invention is how to provide an LED application circuit that stabilizes the current of a thyristor dimmer by acquiring the input voltage and adapting the control signal, thereby ensuring stable output.

[0005] To address the aforementioned issues, this utility model provides an LED application circuit that enhances the compatibility of SCR dimmers, comprising: an input voltage and phase detection module, an adapter control circuit, a main control module, and a sustaining current control circuit. The input terminal of the input voltage and phase detection module is connected to a main power supply, which is an AC input rectified by a SCR voltage regulator and rectifier circuit. The output terminal of the input voltage and phase detection module is connected to the input terminal of the main control module. The output terminal of the adapter control circuit is connected to the input terminal of the main control module to transmit SCR dimmer parameter information to the main control module. The controlled terminal of the sustaining current control circuit is connected to the output terminal of the main control module to generate a corresponding sustaining current according to the control signal from the main control module.

[0006] Furthermore, the input voltage and phase detection module includes a first voltage divider resistor group, the input terminal of which is connected to the main power supply, and the voltage divider output terminal is connected to the input terminal of the main control module.

[0007] Furthermore, the adaptation and control circuit adopts an analog circuit, including a first resistor and a second resistor. The second resistor is an adjustable resistor. The first end of the first resistor is connected to the power supply, and the second end is connected to the first end of the second resistor. The first end of the second resistor is connected to the analog signal input terminal of the main control module, and the second end is grounded.

[0008] Furthermore, the adaptation and control circuit adopts digital circuitry and includes a signal adapter. The input end of the signal adapter collects the digital parameters of the thyristor dimmer, and the output end is connected to the digital communication port of the main control module.

[0009] Furthermore, the sustaining current control circuit includes a first MOSFET and a sustaining load. The drain and source of the first MOSFET and the sustaining load are connected in series and then connected to the main power supply. The gate of the first MOSFET is connected to the BLD output terminal of the main control module.

[0010] Compared with the prior art, the beneficial effects of this utility model are:

[0011] The main control module collects the voltage phase information and dimming parameter information from the main power input, and outputs corresponding drive signals to the sustaining current control circuit accordingly. The sustaining current control circuit then generates a sustaining current of a corresponding magnitude. When dimming to a smaller phase angle, the main circuit current of the LED lighting is smaller. Based on the detection information, the main control module can adjust the sustaining current control circuit to output a larger sustaining current to ensure sufficient sustaining current for the dimmer's thyristor, thereby ensuring stable operation of the LED lighting. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the principle and structure of a traditional fixed holding current circuit in the background technology of this application.

[0013] Figure 2 This is a schematic diagram of the overall principle structure of an embodiment of the present utility model;

[0014] Figure 3 This is a schematic diagram of the principle structure of the input voltage and phase detection module in an embodiment of this utility model;

[0015] Figure 4 A schematic diagram of the principle structure of the first embodiment of the adaptive control circuit of this utility model;

[0016] Figure 5 A schematic diagram of the principle structure of the second embodiment of the control circuit adapted to this utility model;

[0017] Figure 6 This is a schematic diagram of the principle structure of the current control circuit in an embodiment of this utility model. Detailed Implementation

[0018] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0019] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0020] In the description of this specification, references to terms such as "embodiment," "one embodiment," and "one implementation" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or implementation is included in at least one embodiment or illustrative embodiment of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.

[0021] like Figure 2 As shown, this utility model provides an LED application circuit that enhances the compatibility of SCR dimmers, including: an input voltage and phase detection module, an adapter control circuit, a main control module, and a sustaining current control circuit. The input terminal of the input voltage and phase detection module is connected to the main power supply, which is an AC input rectified by a SCR voltage regulator and rectifier circuit. The output terminal of the input voltage and phase detection module is connected to the input terminal of the main control module. The output terminal of the adapter control circuit is connected to the input terminal of the main control module to transmit SCR dimmer parameter information to the main control module. The controlled terminal of the sustaining current control circuit is connected to the output terminal of the main control module to generate a corresponding sustaining current according to the control signal of the main control module.

[0022] In existing SCR LED dimming circuits, such as Figure 1 As shown, after the external AC power passes through the SCR dimmer, rectifier module, and Π-shaped filter, its BLD circuit (i.e., the sustaining current circuit) relies solely on the RC circuit to provide a fixed sustaining current. The subsequent LED driver circuit drives the LED lamp. Thus, when dimming to a smaller phase angle, the power supply current is too low to provide sufficient sustaining current to the dimmer SCR, resulting in unstable LED lamp output.

[0023] In this embodiment, the main control module collects the voltage phase information and dimming parameter information of the main power input (i.e., the output power of the SCR dimmer). The output phase of the SCR dimmer refers to the time point when the SCR is turned on, i.e., the firing angle. Based on this, the main control module outputs a corresponding drive signal to the sustaining current control circuit, which in turn generates a sustaining current of a corresponding magnitude. When dimming to a smaller phase angle, the main circuit current of the LED lighting is smaller. Based on the detection information, the main control module can adjust the sustaining current control circuit to output a larger sustaining current to ensure that sufficient sustaining current is provided to the SCR of the dimmer, thereby ensuring the stable operation of the LED lighting.

[0024] Input voltage and phase detection module, such as Figure 3 As shown, resistors R3 and R4 form the first voltage divider resistor group. The main control module, i.e., the MCU, has its AD port connected to the main power bus via pull-up resistor R3 and grounded via pull-down resistor R4. Resistors R3 and R4 generate a voltage divider. By reading the time interval and effective voltage value of the waveform at this pin, the MCU can obtain the corresponding phase pin during the dimming process of the SCR dimmer. In the main power supply, the external AC input is dimmed by the SCR, then filtered by a filter circuit composed of an inductor and two capacitors, and finally rectified by a rectifier bridge composed of diodes to form the main power output.

[0025] The adaptive control circuit collects dimmer parameters set according to actual needs and feeds the dimmer parameters back to the MCU control. Since there are various ways to set the parameters of existing SCR dimmers, such as on-site potentiometer adjustment and remote intelligent adjustment, this circuit can be implemented by analog circuit or digital method according to the dimming parameter setting method of SCR dimmer.

[0026] The implementation method of analog circuits is as follows: Figure 4 As shown, resistor R1 is connected to the MCU VCC power supply. Resistors R1 and R2 are connected in series to divide the voltage and then connected to the MCU's AD port. Resistor R2 is a variable resistor (it can be a potentiometer, DIP switch, etc.). In this embodiment, the dimming signal of the SCR dimmer is input through a potentiometer, etc. By adjusting the resistance value of resistor R2, the voltage signal at the upper end of resistor R2 changes and is sent to the control unit of the SCR dimmer to realize dimming. Here, the MCU also reads the voltage at this position to obtain the parameter data of the SCR dimmer.

[0027] Digital circuit implementation methods such as Figure 5 As shown, this circuit uses a signal adapter to connect to an external programmer (or wirelessly if using NFC). It obtains parameter information in the same way as the control unit of the SCR dimmer. Internally, it is connected to the corresponding RX and TX pins of the MCU through the TX and RX pins respectively. The parameter data of the corresponding SCR dimmer is transmitted to the MCU through digital lines.

[0028] Maintaining current control circuit such as Figure 6 As shown, resistors R5 and R6 form a sustaining load. By outputting a drive signal to the gate of the first MOSFET Q2, the duty cycle of MOSFET Q2 is changed, thereby altering the current in the sustaining load circuit. The output of the MCU's BLD port serves as the MOSFET drive signal. The drive signal can be a PWM signal. The larger the duty cycle of the drive signal, the larger the current flowing through the sustaining load, i.e., the larger the sustaining current of the main circuit thyristor, and vice versa. This achieves dynamic control of the sustaining current. For example, if the input voltage detection and phase recognition module detects an increase in voltage value, it indicates that the current dimmer requires a larger sustaining current, and the BLD port signal should be increased appropriately; conversely, the BLD port signal should be decreased. If the parameter information of the thyristor dimmer increases, i.e., the dimming pin of the current dimmer thyristor increases, the BLD port signal can be decreased appropriately to reduce power consumption; conversely, the BLD port signal should be increased.

[0029] Although the disclosure is as stated above, the scope of protection of this disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this utility model.

Claims

1. An LED application circuit that enhances the compatibility of silicon controlled rectifier (SCR) dimmers, characterized in that, include: The system comprises an input voltage and phase detection module, an adapter control circuit, a main control module, and a sustaining current control circuit. The input terminal of the input voltage and phase detection module is connected to the main power supply, which is an AC input rectified by a thyristor voltage regulator and a rectifier circuit. The output terminal of the input voltage and phase detection module is connected to the input terminal of the main control module. The output terminal of the adapter control circuit is connected to the input terminal of the main control module to transmit the thyristor dimmer parameter information to the main control module. The controlled terminal of the sustaining current control circuit is connected to the output terminal of the main control module to generate a corresponding sustaining current according to the control signal from the main control module.

2. The LED application circuit for enhancing the compatibility of SCR dimmers according to claim 1, characterized in that, The input voltage and phase detection module includes a first voltage divider resistor group, the input terminal of which is connected to the main power supply, and the voltage divider output terminal is connected to the input terminal of the main control module.

3. The LED application circuit for enhancing the compatibility of SCR dimmers according to claim 1, characterized in that, The adaptation and control circuit adopts an analog circuit, including a first resistor and a second resistor. The second resistor is an adjustable resistor. The first end of the first resistor is connected to the power supply, and the second end is connected to the first end of the second resistor. The first end of the second resistor is connected to the analog signal input terminal of the main control module, and the second end is grounded.

4. The LED application circuit for enhancing the compatibility of SCR dimmers according to claim 1, characterized in that, The adaptive control circuit uses digital circuitry and includes a signal adapter. The input end of the signal adapter collects the digital parameters of the thyristor dimmer, and the output end is connected to the digital communication port of the main control module.

5. The LED application circuit for enhancing the compatibility of SCR dimmers according to claim 1, characterized in that, The sustaining current control circuit includes a first MOSFET and a sustaining load. The drain and source of the first MOSFET and the sustaining load are connected in series and then connected to the main power supply. The gate of the first MOSFET is connected to the output terminal of the main control module.

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