Post by account_disabled on Dec 3, 2017 23:27:34 GMT -5
Hello,
based on DER-294 (PFS) and DER-368 (TFS) we have designed a a complete PS.
TFS primary clamp design is identical with DER-368.
VR3=P6KE150A
R6=100R 1/2W
C2=2,2nF/1kV
Measure DSB level to 595-600Vp, well below DSBmax 725Vp.
Recommended DSBworking <= 675Vp given a margin of 50Vp (DSBmax)
But the clamp overheat at 1A main load.
Measure approx. 188Vp over VR3+R6.
Can a higher Vbr for VR3 be selected ?
P6KE180A or perhaps P6KE200A ?
PFS safegard the Vbus (HD) to 395Vmax+30Vpmax=425Vpmax ( according to spec.)
If the answer is no, kindly describe a methode to lower the voltage stress of VR3+R6.
Any particular critical board design check up´s ?
Please help....
I didn't find the right solution from the Internet.
References
ac-dc.power.com/forum/high-power-design/2015/tfs7704-primary-clamp/
animated commercial product video
based on DER-294 (PFS) and DER-368 (TFS) we have designed a a complete PS.
TFS primary clamp design is identical with DER-368.
VR3=P6KE150A
R6=100R 1/2W
C2=2,2nF/1kV
Measure DSB level to 595-600Vp, well below DSBmax 725Vp.
Recommended DSBworking <= 675Vp given a margin of 50Vp (DSBmax)
But the clamp overheat at 1A main load.
Measure approx. 188Vp over VR3+R6.
Can a higher Vbr for VR3 be selected ?
P6KE180A or perhaps P6KE200A ?
PFS safegard the Vbus (HD) to 395Vmax+30Vpmax=425Vpmax ( according to spec.)
If the answer is no, kindly describe a methode to lower the voltage stress of VR3+R6.
Any particular critical board design check up´s ?
Please help....
I didn't find the right solution from the Internet.
References
ac-dc.power.com/forum/high-power-design/2015/tfs7704-primary-clamp/
animated commercial product video