Is the power supply working in a stable state?

MartinFowler

Is the power supply working in a stable state? [Copy link]

Power supply topology: PSR. Control mode: PSM. Switch chip: LNK3604D.
Input 220VAC, output not fully loaded.
1. How to determine whether the power supply is stable?
2. Can the error in transformer manufacturing affect the FB pin of the switch chip and cause other problems with the power supply?

maychang

Is this the waveform of the first few cycles when the switching power supply starts?

It is impossible to tell whether it is stable from the first few cycles. It will take several more cycles to tell.

qwqwqw2088

The FB feedback pin of this chip has the function of turning the internal MOS on and off.
There may also be problems with the transformer design.

木犯001号

Comments for reference:

LNK3604D is a chip that does jump the PIN, but it does not mean adjustment, but system matching. As long as it is in DCM mode and the duty cycle is too large, close to CRM mode, it will jump to half the frequency (double the period), which is caused by improper design (excessive primary inductance), which makes the system unstable and most likely there will be noise. What you need to do is: 1. Under the lowest input voltage and full load conditions, increase the air gap and reduce the primary inductance until the full DCM mode, and continue to reduce the primary inductance until the full design frequency