CN205320327U - A light wave interrupter circuit and LED control circuit made by using it - Google Patents

Abstract

The utility model discloses a light wave interrupter circuit, which comprises a diode D1, a diode D2, an inductor L1, a MOS tube Q1, a capacitor C1, a capacitor C2 and a capacitor C3; the LED control circuit manufactured by the light wave interrupter circuit comprises an LED and a PWM modulation control end for modulating the LED in a PWM mode; a light wave interrupter circuit is also connected between the PWM modulation control end and the LED; the technical problem is solved by smoothly converting PWM digital current for dimming into undistorted analog current signals, namely converting discontinuous signals into continuous signals through the light wave interrupter circuit, and the LED control circuit designed by utilizing the light wave interrupter circuit is simple in principle and provides the PWM modulation circuit for avoiding the technical problem.

Description

A light wave interrupter circuit and LED control circuit made by using it

technical field

The utility model relates to a light wave interrupter circuit and an LED control circuit manufactured by using the same.

Background technique

Smart homes are becoming more and more popular, especially represented by smart lights, which control various lighting methods of LEDs through the control of the main control chip to output PWM pulse modulation signals; however, in the process of popularizing this method, the applicant also We found some problems with this method, which mainly come down to the following four points: 1. Noise problem; 2. Light strobe problem; 3. Ghosting of the illuminated object; 4. IR infrared signal transmission interference problem; for problem 1, That is, there will be certain noise. In the past, people usually thought that these noises only came from capacitors or transformers, so they only improved capacitors and transformers. However, the applicant found that certain noise is not only from the transformer or capacitor, but also from the resonance noise of the lamp housing during PWM modulation. For problem 2, the problem of stroboscopic light, that is, the problem of constantly turning off the light, this is because PWM itself is a pulse modulation method similar to digital signals, so the stroboscopic problem is difficult to solve. For problem 3, ghost images appear on the illuminated object, that is, the visual effect of a running track on the surface of a fast-moving person or object; this is also due to the PWM modulation method being pulse modulation. For question 4, IR infrared signal transmission interference, through research, it is found that if PWM modulation is used, the receiving and transmitting distance of IR infrared signal will be greatly affected, but people did not know the reason in the past, the applicant found through years of research , this kind of problem is still due to the resonance of the lamp shell during PWM modulation, which has a major impact on the receiving and transmitting distance of IR infrared signals. Therefore, by integrating the above four main problems, it is necessary to design a simple plug-in circuit to interrupt This resonance creates a noise source problem along with other issues mentioned above and a simple LED control circuit is designed using this interrupter circuit.

Utility model content

The purpose of the utility model is to overcome the above-mentioned shortcomings, and provide a light wave interrupter circuit and an LED control circuit made of the light wave interrupter circuit.

In order to achieve the above object, the specific solution of the utility model is as follows: a light wave interrupter circuit, including a diode D1, a diode D2, an inductor L1, a MOS transistor Q1, a capacitor C1, a capacitor C2, and a capacitor C3; the negative electrode of the diode D1 One end of the inductance L1 is connected, the anode of the diode D2 is connected to the other end of the inductance L1; the cathode of the diode D4 is connected to one end of the inductance L1 through the capacitor C3; one end of the inductance L1 is also connected to the ground loop through the capacitor C1; the diode The positive pole of D4 is connected to the other end of the inductor L1, which is also connected to the drain of the MOS transistor Q1;

The gate and source of the MOS transistor are both connected to the ground loop; the cathode of the diode D3 is connected to the other end of the inductor L1, and the anode is connected to the ground loop; the cathode of the diode D2 is connected to the ground loop through the capacitor C2.

An LED control circuit made by using the above-mentioned light wave interrupter circuit, including an LED and a PWM modulation control terminal for modulating the LED in PWM mode; a light wave interrupter circuit is also connected between the PWM modulation control terminal and the LED;

The light wave interrupter circuit: includes a diode D1, a diode D2, an inductor L1, a MOS transistor Q1, a capacitor C1, a capacitor C2, and a capacitor C3; the cathode of the diode D1 is connected to one end of the inductor L1, and the anode of the diode D2 is connected to the inductor L1 The other end of the diode D4; the negative pole of the diode D4 is connected to one end of the inductor L1 through the capacitor C3; one end of the inductor L1 is also connected to the ground loop through the capacitor C1; the positive pole of the diode D4 is connected to the other end of the inductor L1, It is also connected to the drain of the MOS transistor Q1;

The gate and source of the MOS transistor are connected to the ground loop; the cathode of the diode D3 is connected to the other end of the inductor L1, and the anode is connected to the ground loop; the cathode of the diode D2 is connected to the ground loop through the capacitor C2;

The gate of the MOS transistor is also connected to the SW end of the PWM control chip.

Wherein, the MOS transistor is an NMOS transistor.

Wherein, a resistor R1 and a resistor R2 are also included, the gate of the MOS transistor is connected to the ground through the resistor R1, and the source of the MOS transistor is connected to the ground through the resistor R2.

Wherein, a resistor R3 is also included, and the gate of the MOS transistor is connected to the SW terminal of the PWM control chip through the resistor R3.

The beneficial effects of the utility model are: through the light wave interrupter circuit, the PWM digital current used for dimming is smoothly converted into an undistorted analog current signal, that is, the discontinuous signal is converted into a continuous signal, and the above technical problems are solved , and the LED control circuit designed by using the light wave interrupter circuit has a simple principle and provides a PWM modulation circuit that avoids the above-mentioned technical problems.

Description of drawings

Fig. 1 is a block diagram of the utility model;

Fig. 2 is a schematic diagram of the utility model.

detailed description

The utility model will be described in further detail below in conjunction with the accompanying drawings and specific embodiments, and the scope of implementation of the utility model is not limited thereto.

As shown in Figures 1 to 2, a light wave interrupter circuit described in this embodiment includes a diode D1, a diode D2, an inductor L1, a MOS transistor Q1, a capacitor C1, a capacitor C2, and a capacitor C3; the diode D1 The negative pole of the diode D2 is connected to one end of the inductor L1, and the positive pole of the diode D2 is connected to the other end of the inductor L1; the negative pole of the diode D4 is connected to one end of the inductor L1 through the capacitor C3; one end of the inductor L1 is also connected to the ground loop through the capacitor C1; The anode of the diode D4 is connected to the other end of the inductor L1, and is also connected to the drain of the MOS transistor Q1; the gate and the source of the MOS transistor are connected to the ground loop; the cathode of the diode D3 is The other end of the inductor L1 is connected, and its anode is connected to the ground loop; the cathode of the diode D2 is connected to the ground loop through the capacitor C2. Specifically, the diode D1 is responsible for converting the PWM high-frequency high-precision digital constant-current dimming current into a unidirectional analog DC current, and then the capacitor C1 is responsible for filtering the high-frequency signal left by the converted PWM to obtain a smooth analog working current; Inductor L1 and MOS transistor Q1 convert the smooth current through high frequency (synchronous switching frequency with the previous transformer) to high-frequency AC voltage again. Diode D2 and capacitor C2 are responsible for rectifying and re-commutating the high-frequency AC voltage. Filtering makes the analog DC current ultra-smooth (up to mV level ripple) LED pure DC working current. Diode D3, diode D4 and capacitor C3 form the loop peak absorption and freewheeling circuit during high-frequency switching, and the main force is to absorb the EMI problem in the switching circuit of MOS transistor Q1. The P1 interface in the circuit is connected to the SW pin of the PWM pre-driver IC, synchronously obtains the same high-frequency transformer switching signal as the IC, and then performs secondary energy conversion to completely isolate the digital dimming PWM switching signal, thus enabling the LED module to obtain Green, very environmentally friendly and healthy lighting source. In fact, the resonance problem is avoided by converting the discontinuous signal into a continuous signal; it should be noted here that before solving the resonance problem, the applicant found out that it is used for tuning after many tests and verifications day and night. The light PWM signal light source wave hits the light diffuser cover on the LED beads in a short distance, and the same resonance signal as the PWM dimming signal occurs, which makes the light diffuser resonate with the lamp shell and produces noise. This problem is named in this paper: Light wave resonance. Therefore, solving the problem of light wave resonance will also have a revolutionary impact on avoiding the above-mentioned problems for LEDs in smart homes. In addition, converting discontinuous signals into continuous signals also solves the problem of stroboscopic flicker, killing two birds with one stone.

An LED control circuit made by using the above-mentioned light wave interrupter circuit, including an LED and a PWM modulation control terminal for modulating the LED in PWM mode; a light wave interrupter circuit is also connected between the PWM modulation control terminal and the LED; The light wave interrupter circuit: includes a diode D1, a diode D2, an inductor L1, a MOS transistor Q1, a capacitor C1, a capacitor C2, and a capacitor C3; the cathode of the diode D1 is connected to one end of the inductor L1, and the anode of the diode D2 is connected to the inductor L1 The other end of the diode D4; the negative pole of the diode D4 is connected to one end of the inductor L1 through the capacitor C3; one end of the inductor L1 is also connected to the ground loop through the capacitor C1; the positive pole of the diode D4 is connected to the other end of the inductor L1, It is also connected to the drain of the MOS transistor Q1; the gate and the source of the MOS transistor are connected to the ground loop; the cathode of the diode D3 is connected to the other end of the inductor L1, and the anode is connected to the ground loop; The cathode of the diode D2 is connected to the ground loop through the capacitor C2; the gate of the MOS transistor is also connected to the SW terminal of the PWM control chip. This connection principle is based on the principle of the above-mentioned light wave interrupter, mainly by converting discontinuous signals into continuous signals to avoid resonance problems;

In the LED control circuit manufactured by using the light wave interrupter circuit described in this embodiment, the MOS transistor is an NMOS transistor. NMOS tubes are low in cost and easy to use.

The LED control circuit made by using the light wave interrupter circuit described in this embodiment also includes a resistor R1 and a resistor R2. The gate of the MOS tube is connected to the ground through the resistor R1, and its source is connected to the ground through the resistor R2. Connect the ground back. Wherein, a resistor R3 is also included, and the gate of the MOS transistor is connected to the SW terminal of the PWM control chip through the resistor R3. Resistors R1-R3 all play the role of voltage division and current limiting, firstly protect each component, and also provide conditions for port matching of each component.

The above is only a preferred embodiment of the utility model, so all equivalent changes or modifications made according to the structure, features and principles described in the scope of the utility model patent application are included in the protection of the utility model patent application. within range.

Claims (5)

1. A light wave interrupter circuit, characterized in that: comprise diode D1, diode D2, inductor L1, MOS transistor Q1, capacitor C1, capacitor C2, capacitor C3; the negative pole of said diode D1 is connected to one end of inductor L1, and the diode The positive pole of D2 is connected to the other end of the inductor L1; the negative pole of the diode D4 is connected to one end of the inductor L1 through the capacitor C3; one end of the inductor L1 is also connected to the ground loop through the capacitor C1; the positive pole of the diode D4 is connected to the inductor L1 The other end of L1 is connected, which is also connected to the drain of MOS transistor Q1; The gate and source of the MOS transistor are both connected to the ground loop; the cathode of the diode D3 is connected to the other end of the inductor L1, and the anode is connected to the ground loop; the cathode of the diode D2 is connected to the ground loop through the capacitor C2. 2. A LED control circuit utilizing the light wave interrupter circuit of claim 1, comprising LED and a PWM modulation control terminal for modulating the LED in PWM mode; it is characterized in that: between the PWM modulation control terminal and the LED It is also equipped with a light wave interrupter circuit; The light wave interrupter circuit: includes a diode D1, a diode D2, an inductor L1, a MOS transistor Q1, a capacitor C1, a capacitor C2, and a capacitor C3; the cathode of the diode D1 is connected to one end of the inductor L1, and the anode of the diode D2 is connected to the inductor L1 The other end of the diode D4; the negative pole of the diode D4 is connected to one end of the inductor L1 through the capacitor C3; one end of the inductor L1 is also connected to the ground loop through the capacitor C1; the positive pole of the diode D4 is connected to the other end of the inductor L1, It is also connected to the drain of the MOS transistor Q1; The gate and source of the MOS transistor are connected to the ground loop; the cathode of the diode D3 is connected to the other end of the inductor L1, and the anode is connected to the ground loop; the cathode of the diode D2 is connected to the ground loop through the capacitor C2; The gate of the MOS transistor is also connected to the SW end of the PWM control chip. 3. The LED control circuit according to claim 2, wherein the MOS transistor is an NMOS transistor. 4. The LED control circuit according to claim 2, characterized in that: it also includes a resistor R1 and a resistor R2, the gate of the MOS transistor is connected to the ground through the resistor R1, and its source is connected to the ground through the resistor R2. . 5 . The LED control circuit according to claim 2 , further comprising a resistor R3 , the gate of the MOS transistor is connected to the SW terminal of the PWM control chip through the resistor R3 .