Switching power supply noise how to solve
Switching power supply is a kind of electronic equipment that can convert 100V-260V AC power into stable 5V, 12V, 24V DC power, this kind of power supply will turn the input voltage into spark through high frequency switching circuit, so as to achieve the purpose of efficient voltage reduction. However, the noise generated during the use of switching power supply is a concern for many people. In this paper, we will introduce the reasons for switching power supply noise and how to take effective measures to reduce switching power supply noise.
Switching power supply noise causes
1. Magnetic field interference
Switching power supply in the high-frequency magnetic field will interfere with other electronic equipment around, resulting in electromagnetic radiation noise.
2. Capacitor parallel connection
Switching power supply filter capacitors in parallel will also produce noise, this noise is usually high-frequency noise.
3. Driving voltage
The driving circuit of the switching power supply is a high-frequency circuit, and due to the transmission characteristics of high-frequency signals, the driving voltage will produce RF interference, which will affect the stability of the switching power supply.
4. Inductive leakage
Inductive leakage in the switching power supply is also one of the reasons for noise.
Switching power supply noise solutions
1. Reduce capacitor parallel noise
Switching power supply capacitor parallel is the main source of high-frequency noise, in order to reduce capacitor parallel noise, need to take the following measures:
(1) The use of organic electrolytic capacitors: organic electrolytic capacitors have a relatively small capacitance, the corresponding noise is also small.
(2) The use of a number of small capacitance capacitors in parallel: a number of small capacitance capacitors in parallel can share the noise generated by the parallel connection of capacitors.
(3) Use independent power supply: independent power supply can effectively reduce the noise generated by parallel connection of capacitors.
2. Enhance the shielding
Shielding is an effective noise reduction method, through the use of appropriate shielding materials, can effectively reduce the interference of electronic equipment and the surrounding environment.
(1) Improve the shielding performance: Select shielding materials with better shielding performance, such as ferromagnetic materials, aluminium foil, copper foil, etc.
(2) Increase the number of shielding layers: When one layer of shielding is not enough to meet the requirements in the key parts, the number of shielding layers can be increased on the basis of the original.
3. Reduce the noise of driving voltage
The driving voltage of the switching power supply is one of the main factors of noise, in order to reduce the noise of the driving voltage, the following measures can be taken:
(1) Choose a suitable power supply: selecting a more stable power supply can greatly reduce the impact of the noise generated by the switching power supply.
(2) Reduce the noise of the drive voltage: the noise of the drive voltage can be reduced by the power supply filter capacitor, magnetic beads, torque magnetic ring, TLPI network and so on.
4. Reduce the noise of inductor leakage
Inductive leakage is also one of the causes of switching power supply noise. In order to reduce the inductor leakage noise, the following measures can be taken:
(1) Choose high quality inductor: Choosing raw materials with good inductor quality can greatly reduce the inductor leakage noise.
(2) Adopt magnetic shielding technology: Adopting magnetic shielding technology in the key parts can effectively reduce the noise generated by magnetic leakage of inductors.
