Hi to all.
I have a design using a TFS7708 switcher. Input is 380VDC ( from a PFC) and output is 26V @ 15A.
I have noticed that at no load the TFS is getting quite warm. It is on a 8dec C/watt heatsink and it is at about 60degC
with no load. Ambient @ 28deg C.
I have not used this chip before so I'm not sure what is "normal" :0)
If I disable the main switcher and only leave the small flyback running , the temperature drops to almost ambient , so it's definitely
the main converter generating the heat.
If I run the main converter at high load( about 350W) I can run for a few minutes before the heatsink gets to 80deg C so I think
the basic design is ok. I tried increacing my transformer magnetising inductance ( I'm now at 20mH) and that seemed to help a little
but I'm now in danger of saturating under high load.
If this is not normal , where can I start looking to find what is causing the heating of the switcher?
I'm fairly new to this , so I may be missing something obvious :0)
TFS7708 high idle temperature.
Hi to all.