Power supply problem
So, I built up the circut in the schematic below and it seems like it is getting loaded down by something. RS801 is getting really hot. Can anyone help me find out why my power supply isn't working properly? Thanks
Comments
Hi,
Is there any specific reason not to use ferrite bead in series with the output diode? because we are using that in our design. what is the reason?
Thanks in advance
Hi,
A ferrite bead on one of the legs of the output diode will add a small inductance in series with the output diode. This inductance will prevent the diode from getting fully biased quickly when the winding polarities change when the flyback cycle begins. This will increase the power dissipation in your primary side snubber.
Unless the bead is added for EMI reduction, this bead is not recommended/necessary.
Regards
PI-Sarek
A bead on the output diode appears as a leakage inductance. Leakage inductance in a flyback is parastitic and increases losses in the primary snubber. This is especially bad if you have a single output flyback, or in the case of a multiple output flyback, if the bead is placed in the diode of the higher current output.
RS801 is in a Drain-Source RC snubber configuration. Power Integrations does not recommend such a snubber arrangement, because of the associated power loss.
In addition, you seem to have a ferrite bead in series with the output diode. This is also not recommended, especially with a single output flyback.
Pls. download and use PI Expert, and study our recommended circuits and Design Ideas similar to your power level.