Somewhat inefficent, but I was wondering if it's possible to parallel high power damper diodes such as EY100 either in a full wave or a bridge rectifier followed by LCL filter to increase the current rating. Would this work and would it double the current rating.
The application would be a low voltage supply of around 24volts and 1 amp.
Regards
The application would be a low voltage supply of around 24volts and 1 amp.
Regards
Neither TDSL or Frank Philipse show EY100. Perhaps you "fat fingered" the type.
In any event, damper diodes do exhibit a relatively small forward drop. However, its still much larger than that found in SS diodes. Build a hybrid bridge and enjoy the benefits of damper diodes, without the doubled forward drop penalty. If you use high PIV Schottky diodes, like Cree's C4D05120A on the ground side of the bridge, no SS diode switching noise is of concern. You also eliminate heater supply hassles.
In any event, damper diodes do exhibit a relatively small forward drop. However, its still much larger than that found in SS diodes. Build a hybrid bridge and enjoy the benefits of damper diodes, without the doubled forward drop penalty. If you use high PIV Schottky diodes, like Cree's C4D05120A on the ground side of the bridge, no SS diode switching noise is of concern. You also eliminate heater supply hassles.
PY500 is probably the cheapest and most abundant color TV booster diode. 11W anode dissipation, the filament draw is 12W. According to datasheet, the internal resistence is 45.5 ohm measured at the maximum average current of 440 mA: 20V drop across the tube. Massively inefficient at 24V 1A. You may check a Tungar rectifier instead. Some are designed to be used also in car battery chargers.
PY33 is not a bad option either and very cheap - not quite the current capacity of the PY500 and the peak-inverse-voltage rating is quite a bit lower (only 700V), but you don't have the top-cap to think about. Heater is nominally 29 volts (you can use 30 quite happily). If putting dampers in parallel, their might be benefit in a small series resistance for each (a few ohms at the most) to help current sharing.
Thank you for the suggestions. I've got some SiC diodes so could give that a try. I was thinking of the EY500/A as it's cheap and I haven't found any dampers with a much higher current rating. I'll have a look for the PY500 and PY33.
Looking at PSU Designer CL appears to produce a lower voltage drop than LC. Would it be better or worse to have a capacitor on the input. I've got two inductors 160mH/900mohm each to play with.
Looking at PSU Designer CL appears to produce a lower voltage drop than LC. Would it be better or worse to have a capacitor on the input. I've got two inductors 160mH/900mohm each to play with.
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> 160mH is very low for an LC filter
Yes, for "normal" work like 400V 200mA (2K equivalent).
His proposed 24V 1A supply is more like 24 Ohms load. We would ballpark a choke 2,000/24 or 100X smaller. Then 5H-10H comes out 50mH to 100mH. 160mH seems very ample.
I *think* you will have much lower drop in the tube choke-input, because the current flows 90+% of the time. With cap-input, a very high current flows 10% of the time.
Yes, for "normal" work like 400V 200mA (2K equivalent).
His proposed 24V 1A supply is more like 24 Ohms load. We would ballpark a choke 2,000/24 or 100X smaller. Then 5H-10H comes out 50mH to 100mH. 160mH seems very ample.
I *think* you will have much lower drop in the tube choke-input, because the current flows 90+% of the time. With cap-input, a very high current flows 10% of the time.
I always pay attention to what Eli has to say coz he knows his "stuff". In this case however I would suggest that when using a hybrid bridge there is no point in using anything but bog standard SS diodes in the ground side. The current paths are always via 1 tube diode and 1 SS diode. The tube diode blocks any solid state switching noise so the Cree Schottky diodes would be an "overkill".
Cheers,
Ian
Ian is absolutely right about the vacuum diodes in a hybrid bridge blocking SS diode switching noise, from entering the B+ rail. I suggested Schottkys primarily for psychological reasons. No switching noise, whatsoever, provides a "warm, fuzzy, feeling".
BTW, I wonder if switching noise might work its way into the power trafo.
Schottkys would certainly eliminate that. Of course, snubber networks would do the same thing.
BTW, I wonder if switching noise might work its way into the power trafo.
Schottkys would certainly eliminate that. Of course, snubber networks would do the same thing.- Status
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