Main products: power adapter, medical power, LED power, charger and so on.
Shenzhen Lianyunda Electronics Co., Ltd. is committed to doing a good job in power supply products, and sincerely welcomes customers to contact us by phone or email.
Power adapter transformer process problem
1 The dipping paint is not in place, causing the magnetic core to be weak and causing mechanical vibration to make a sound;
2 The length of the air gap is not suitable, causing the working state of the power adapter transformer to be unstable and making a sound;
The fact that the 3-wire package is not tight may also cause a sound;
4 magnetic core combination has air gap, causing air vibration and sound when high frequency (the power adapter transformer is fully immersed in vacuum, and the epoxy resin in the middle column, the epoxy resin between the skeleton and the core) - refer to the following figure The position of the box is generally not sounding).
Power adapter transformer loop problem
The loop problem of the power adapter transformer means that the loop of the transformer oscillates and causes the transformer to whistle.
1 The circuit board is improperly wired, causing interference to cause oscillation and causing noise;
2 The feedback loop parameters are set incorrectly, causing the loop to be unstable and causing oscillations to make a sound;
The quality problems of the components in the 3 loop, such as the insufficient capacity of the input filter capacitor, the quality of the output rectification fast recovery diode is not good, the quality of the power MOS tube is not good, the high voltage capacitance of the RCD recoil absorption loop or the quality of the diode is not good, etc. Problems can cause shocks and cause noise.
Transformer core problem
When the transformer core is saturated, the current in the coil increases, the transformer generates heat and generates self-excited oscillation, and the oscillation of the coil causes vibration of the surrounding air to make a sound.
Power adapter load problem
1 The power adapter will oscillate at some working points under no-load or light-load conditions, which is manifested by the whistling of the power adapter transformer and the instability of the output.
This phenomenon occurs because the instantaneous turn-on time of the switch is too large due to the no-load/light load, resulting in too much output energy, and the voltage overshoot is also large. It takes a long time to recover to the normal voltage, so the switch needs to stop working. For a period of time, the switch operates in an intermittent mode of operation, causing the power adapter transformer to vibrate at a lower frequency (a regular intermittent full cut-off period or a frequency at which the duty cycle changes drastically).
2 power adapter transformer works in a serious overload state, there is always the possibility of burning - this is the origin of many "screams" before the power supply burned.