An anti-interference LED driving power supply EMC optimization filter circuit

Abstract

The utility model discloses an anti -interference LED drive power supply EMC optimization filter circuit, including filter circuit, filter circuit includes power input interface, first filter circuit, second filter circuit and power output circuit, one end of first filter circuit and one end of second filter circuit all are connected with one end of power input interface, the other end of first filter circuit and the other end of second filter circuit all are connected with one end of power output circuit, the utility model discloses an anti -interference LED drive power supply EMC optimization filter circuit, this circuit takes the corresponding filter circuit to restrain high -frequency sharp peak pulse generation EMI filter in AC power output port, has reduced the influence that sharp peak pulse has caused to the circuit, avoided appearing for reducing EMI effect and makes the phenomenon of power ripple deterioration appears, can effectively restrain the two kinds of noises that exist universally in switching power supply circuit to make switching power supply output voltage more stable, has guaranteed the normal operation of circuit.

Description

Technical Field

[0001] This utility model relates to the field of EMC optimized filtering circuit technology, specifically to an anti-interference LED driver power supply EMC optimized filtering circuit. Background Technology

[0002] Switching power supplies are widely used in electronic devices and the electronics and information industry due to their significant advantages, such as small size, light weight, and high efficiency. They have a significant impact on modern electronic information technology. A switching power supply is a power supply that outputs a stable voltage by controlling the on and off times of a power transistor. A complete switching power supply includes a rectifier and filter circuit, a transformer, a comparator and amplifier circuit, a JFET transistor, and a pulse frequency modulation circuit, etc.

[0003] However, traditional EMC-optimized filter circuits have the following drawbacks:

[0004] Traditional EMC-optimized filter circuits have poor resistance to EMI noise. EMI noise will affect the normal operation of electronic devices and the communication quality of electronic communication equipment, and will also have a significant impact on weak signal detection circuits. Utility Model Content

[0005] The purpose of this invention is to provide an anti-interference LED driver power supply EMC optimized filter circuit to solve the problem mentioned in the background art that the traditional EMC optimized filter circuit has poor resistance to EMI noise, which will affect the normal operation of electronic devices and the communication quality of electronic communication equipment, and will have a significant impact on weak signal detection circuits.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an anti-interference LED driver power supply EMC optimization filter circuit, comprising a filter circuit, wherein the filter circuit includes a power input interface, a first filter circuit, a second filter circuit, and a power output circuit, wherein one end of the first filter circuit and one end of the second filter circuit are both connected to one end of the power input interface, and the other end of the first filter circuit and the other end of the second filter circuit are both connected to one end of the power output circuit.

[0007] Preferably, the first filter circuit includes an integrated circuit U1, a capacitor C1, an inductor L1, a capacitor C2, a capacitor C3, an inductor L2, a capacitor C4, a capacitor C5, and a resistor RL. The 8 pins of the integrated circuit U1 are connected to one end of the capacitor C1 and one pin of the inductor L1, respectively. The 4 pins of the integrated circuit U1 are connected to the other end of the capacitor C1 and one pin of the inductor L1, respectively. The 3 pins of the inductor L1 are connected to one end of the capacitor C2 and one end of the inductor L2, respectively. The other end of the inductor L2 is connected to one end of the capacitor C4, one end of the capacitor C5, and one end of the resistor RL, respectively. The 4 pins of the inductor L1 are connected to one end of the capacitor C3, the other end of the capacitor C4, the other end of the capacitor C5, and the other end of the resistor RL, respectively. The other ends of the capacitors C2 and C3 are both grounded.

[0008] Preferably, pins 2 and 3 of the integrated circuit U1 are both connected to the power input interface.

[0009] Preferably, the second filter circuit includes an inductor L3, a capacitor C6, a capacitor C7, a capacitor C8, and a driver chip. The VCC pin of the driver chip is connected to one end of the capacitor C6, one end of the capacitor C7, one end of the capacitor C8, and one end of the inductor L3, respectively. The GND pin of the driver chip, the other end of the capacitor C6, the other end of the capacitor C7, and the other end of the capacitor C8 are all grounded.

[0010] Preferably, the other end of the inductor L3 is connected to the power input interface.

[0011] Compared with the prior art, the beneficial effects of this utility model are: the circuit adopts the addition of a corresponding filter circuit at the AC power output port to suppress the generation of EMI filtering by high-frequency spike pulses, thereby reducing the impact of spike pulses on the circuit. In addition, the setting of the second filter circuit avoids the phenomenon of power supply ripple deterioration in order to reduce EMI effect. It can effectively suppress the two types of noise that are common in switching power supply circuits, thereby making the output voltage of the switching power supply more stable and ensuring the normal operation of the circuit. Attached Figure Description

[0012] Figure 1 The figure is for this utility model;

[0013] Figure 2 This is a circuit diagram of the first filter circuit of this utility model;

[0014] Figure 3 This is a circuit diagram of the second filter circuit of this utility model. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0016] Please see Figure 1-3 This utility model provides an anti-interference LED driver power supply EMC optimized filtering circuit, including a filtering circuit, which includes a power input interface, a first filtering circuit, a second filtering circuit, and a power output circuit. One end of the first filtering circuit and one end of the second filtering circuit are both connected to one end of the power input interface, and the other end of the first filtering circuit and the other end of the second filtering circuit are both connected to one end of the power output circuit.

[0017] The first filter circuit includes an integrated circuit U1, a capacitor C1, an inductor L1, a capacitor C2, a capacitor C3, an inductor L2, a capacitor C4, a capacitor C5, and a resistor RL. The 8th pin of the integrated circuit U1 is connected to one end of capacitor C1 and one end of inductor L1, respectively. The 4th pin of the integrated circuit U1 is connected to the other end of capacitor C1 and one end of inductor L1, respectively. The 3rd pin of inductor L1 is connected to one end of capacitor C2 and one end of inductor L2, respectively. The other end of inductor L2 is connected to one end of capacitor C4, one end of capacitor C5, and one end of resistor RL, respectively. The 4th pin of inductor L1 is connected to one end of capacitor C3, the other end of capacitor C4, the other end of capacitor C5, and the other end of resistor RL, respectively. The other ends of capacitors C2 and C3 are both grounded.

[0018] Pins 2 and 3 of integrated circuit U1 are both connected to the power input interface.

[0019] The second filter circuit includes an inductor L3, capacitors C6, C7, and C8, and a driver chip. The VCC pin of the driver chip is connected to one end of capacitor C6, one end of capacitor C7, one end of capacitor C8, and one end of inductor L3, respectively. The GND pin of the driver chip, the other end of capacitor C6, the other end of capacitor C7, and the other end of capacitor C8 are all grounded.

[0020] The other end of inductor L3 is connected to the power input interface.

[0021] In this embodiment, the high-voltage power from the transmission network first passes through the switching power supply module. The output is then connected to a low-pass filter circuit composed of a differential-mode inductor and a differential-mode capacitor to eliminate low-frequency differential-mode interference noise. Next, the output is passed through an electromagnetic interference filter circuit composed of a common-mode inductor and a common-mode capacitor to suppress the generation of high-frequency pulse noise. Since the common-mode inductor consists of multiple windings (in this case, two windings), and there is a gap between the windings, magnetic flux leakage is likely to occur, leading to interference noise and affecting the normal operation of the circuit. To solve this problem, the output voltage can be passed through a differential-mode LC filter circuit to remove residual interference. To suppress low-frequency interference, the filter circuit was tested and found to effectively suppress differential-mode interference and common-mode interference. Transient current flows through the power supply filter circuit to the chip power supply terminal, then through the internal circuit and back to the negative power supply terminal via the PCB ground plane. Since there is always an impedance between the power supply and the chip and the ground plane, and this impedance is discontinuous, this backflow process will generate radiation and reflection. After multiple round trips, this radiation and reflection can easily form standing waves, which manifest as strong noise and strong EMI radiation near certain frequencies, usually located near the edge of the PCB power supply and ground plane.

[0022] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An anti-interference LED driver power supply EMC optimization filter circuit, comprising a filter circuit, characterized in that: The filtering circuit includes a power input interface, a first filtering circuit, a second filtering circuit, and a power output circuit. One end of the first filtering circuit and one end of the second filtering circuit are both connected to one end of the power input interface, and the other end of the first filtering circuit and the other end of the second filtering circuit are both connected to one end of the power output circuit.

2. The anti-interference LED driver power supply EMC optimized filtering circuit according to claim 1, characterized in that: The first filter circuit includes an integrated circuit U1, a capacitor C1, an inductor L1, a capacitor C2, a capacitor C3, an inductor L2, a capacitor C4, a capacitor C5, and a resistor RL. Pin 8 of the integrated circuit U1 is connected to one end of capacitor C1 and pin 1 of inductor L1. Pin 4 of the integrated circuit U1 is connected to the other end of capacitor C1 and pin 2 of inductor L1. Pin 3 of inductor L1 is connected to one end of capacitor C2 and one end of inductor L2. The other end of inductor L2 is connected to one end of capacitor C4, one end of capacitor C5, and one end of resistor RL. Pin 4 of inductor L1 is connected to one end of capacitor C3, the other end of capacitor C4, the other end of capacitor C5, and the other end of resistor RL. The other ends of capacitors C2 and C3 are both grounded.

3. The anti-interference LED driver power supply EMC optimized filtering circuit according to claim 2, characterized in that: Pin 2 and pin 3 of the integrated circuit U1 are both connected to the power input interface.

4. The anti-interference LED driver power supply EMC optimized filtering circuit according to claim 1, characterized in that: The second filter circuit includes an inductor L3, a capacitor C6, a capacitor C7, a capacitor C8, and a driver chip. The VCC pin of the driver chip is connected to one end of the capacitor C6, one end of the capacitor C7, one end of the capacitor C8, and one end of the inductor L3, respectively. The GND pin of the driver chip, the other end of the capacitor C6, the other end of the capacitor C7, and the other end of the capacitor C8 are all grounded.

5. The anti-interference LED driver power supply EMC optimized filtering circuit according to claim 4, characterized in that: The other end of the inductor L3 is connected to the power input interface.

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