CN202535612U - Special dimming circuit for integrated LED (light-emitting diode) lamp - Google Patents

Abstract

The utility model discloses an integrated dimming circuit for LED lamps, which includes a silicon controlled rectifier SCR, a rectification filter circuit A and a CPU control unit, the output end of the silicon controlled rectifier SCR is connected with the rectification filter circuit A, and also includes a resistor R1, Resistor R2, resistor R3, diode D1 and capacitor C2, resistor R1 and diode D1 are connected in parallel, the output terminal of the rectification filter circuit is connected to the input terminal after resistor R1 and diode D1 are connected in parallel, and the output is divided after resistor R1 and diode D1 are connected in parallel Two circuits, the first circuit is connected to the resistor R2, the second circuit is connected to the capacitor C2 and the resistor R3 in turn, the first circuit and the second circuit are connected to the CPU control unit, and the CPU control unit is connected to the LED drive circuit. The circuit structure is very simple. One diode, one capacitor, several resistors, almost no heat, the efficiency of electro-optical conversion is very high, the cost is low, the most important thing is that the volume is very small, suitable for installation in the narrow space of the integrated LED lamp.

Description

An integrated LED lamp dedicated dimming circuit

Technical field:

The utility model relates to an integrated dimming circuit specially used for LED lamps.

Background technique:

The traditional LED dimming circuit is shown in Figure 1. It consists of bidirectional thyristor switch SCR0, rectifier circuit A0, isolation circuit U10, microcontroller control unit (MCU0) and LED drive circuit (LED drive0). The working process is: AC The sine wave waveform is chopped by the bidirectional thyristor switch SCR0, rectified by the rectifier circuit A0, and the chopped waveform is taken out by the isolation circuit U10 and sent to the single-chip control unit (MCU0), and the single-chip control unit (MCU0) outputs the PWM waveform to the LED drive circuit (LED drive0), the LED drive circuit (LED drive0) drives the LED to emit light. The above-mentioned LED dimming circuit has a complex structure and many electronic components, resulting in large heat generation, large reactive power generation, very low efficiency, and too large a volume, so it cannot be used as an integrated LED lamp driving circuit at all.

Invention content:

The purpose of the utility model is to overcome the above-mentioned shortcomings of the prior art, and provide an integrated LED lamp dedicated dimming circuit with simple structure, small volume, low calorific value and low cost.

The purpose of the invention of the utility model can be achieved through the following technical solutions: an integrated dimming circuit for LED lights, including a silicon controlled rectifier SCR, a rectifier filter circuit A and a CPU control unit, a silicon controlled rectifier SCR output terminal and a rectifier The filter circuit A is connected, and also includes a resistor R1, a resistor R2, a resistor R3, a diode D1 and a capacitor C2, the resistor R1 is connected in parallel with the diode D1, and the output terminal of the rectifier filter circuit is connected to the input terminal after the parallel connection of the resistor R1 and the diode D1 , the resistor R1 is connected in parallel with the diode D1, and the output is divided into two circuits. The first circuit is connected to the resistor R2, and the second circuit is connected to the capacitor C2 and the resistor R3 in turn. After the first circuit and the second circuit are combined, they are connected to the CPU control unit. Connect with LED driver circuit.

After adopting the technical solution, the beneficial effect of the utility model is: the circuit structure is very simple, one diode, one capacitor, several resistors, almost no heat, the efficiency of electro-optical conversion is very high, the cost is low, and the most important thing is that the volume is very small, It is suitable for installation in the narrow space of the integrated LED lamp.

Description of drawings:

FIG. 1 is a structural schematic diagram of a prior art LED lamp driving circuit;

Fig. 2 is a structural principle diagram of the integrated LED lamp special dimming circuit of the utility model.

Detailed ways:

The technology will be further described below in conjunction with the accompanying drawings.

The integrated dimming circuit for LED lights in this embodiment includes a silicon controlled rectifier SCR, a rectification and filtering circuit A and a CPU control unit, the output terminal of the silicon controlled rectifier SCR is connected to the rectification and filtering circuit A, and also includes a resistor R1, a resistor R2, Resistor R3, diode D1 and capacitor C2, resistor R1 and diode D1 are connected in parallel, the output terminal of rectification filter circuit A is connected to the input terminal after resistor R1 and diode D1 are connected in parallel, and the output is divided into two circuits after resistor R1 and diode D1 are connected in parallel , the first road is connected to the resistor R2, the second road is connected to the capacitor C2 and the resistor R3 in turn, the first road and the second road are connected to the CPU control unit after being merged, and the CPU control unit is connected to the LED driving circuit. Here, the capacitor in the rectification filter circuit A is called filter capacitor C1.

Due to the existence of the diode D1, the capacitor C2 charges quickly and can always track the maximum value of the filter capacitor C1 of the rectifier filter circuit A. If the SCR conduction angle is less than 90°, the maximum value of the capacitor C2 should be the AC input voltage The peak value; if the conduction angle of the thyristor is greater than 90°, the maximum value of the capacitor C2 should be proportional to the sine of the conduction angle of the thyristor. When the voltage value of the rectifier filter capacitor C1 is less than C2, C2 discharges to C1, and the discharge time constant is about 1/4 (5ms) of the power cycle. The minimum value of capacitor C2 is closely related to the discharge time and the voltage waveform of capacitor C1.

Since the conduction angle of the thyristor is greater than 90°, it can be measured by the maximum value of capacitor C2. We focus on the situation when the conduction angle of the thyristor is less than 90°. When the conduction angle is less than 90°, the maximum value is unchanged. Both are equal to the value at 90°. When the electrical angle exceeds 90°, C2 starts to discharge to C1. After zero crossing, C2 continues to discharge to C1 before the SCR is not turned on. The further the conduction angle is, the deeper the discharge will be. , the smaller the minimum value of the capacitor C2, the comprehensive analysis of the maximum and minimum values of the capacitor C2 and the time difference between them can calculate the conduction angle when the conduction angle is less than 90°. In short, the computer chip samples and analyzes the voltage waveform of the waveform measurement capacitor C2 to measure the conduction angle of the thyristor, which can then be used to control the brightness of the LED lamp.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model in any form. Any person familiar with the art, without departing from the scope of the technical solution of the utility model, can use the method and technical content disclosed above to make many possible changes and modifications to the technical solution of the utility model, or modify it into an equivalent change, etc. effective example. Therefore, all equivalent changes made according to the shape, structure and principle of the utility model that do not deviate from the technical solution of the utility model should be covered within the protection scope of the utility model.

Claims (1)

1. the special-purpose light adjusting circuit of an integral LED lamp; Include controllable silicon SCR, current rectifying and wave filtering circuit A and CPU control unit; The controllable silicon SCR output is connected with current rectifying and wave filtering circuit A, it is characterized in that: also include resistance R 1, resistance R 2, resistance R 3, diode D1 and capacitor C 2, resistance R 1 is connected in parallel with diode D1; The output of current rectifying and wave filtering circuit A and resistance R 1 are connected with input after diode D1 is connected in parallel; Output divided two-way after resistance R 1 was connected in parallel with diode D1, and the first via connects resistance R 2, the second tunnel and connects capacitor C 2 and resistance R 3 successively; The first via and the second tunnel is converged the back and is connected with the CPU control unit, and the CPU control unit is connected with led drive circuit.

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