high speed diode to-220 package for Aleph-x

[rwagter]

I recently bought 4 of peranders rectifier pcb's for my upcoming Aleph-x:

An externally hosted image should be here but it was not working when we last tested it.

however the pcb only accepts to-220 package diodes. Most schottky's or the like which allow for the current used in the Aleph-x are in to-247 style package.

Anyone have a tip on high speed soft recovery diodes in to-220 package which allow for + 20A ?

Ralph

 

[roddyama]

Ralph,

The MUR 1560 is a TO220 and is good for 15A which would make the full bridge good for 30A. What amp would you be making that needs more than that?

 

[rwagter]

30A is indeed more then enough but as the master always says:
"it is never enough"

Since initial powerup give large current peeks to charge all caps I like to be on the safe side of things

With PSU designerII I get with 15V toroid a regular bridge, 220mF stubby (11.7mOhm) and a 8Ohm load a peak of 250A , hence my question

 

[roddyama]

Since initial powerup give large current peeks to charge all caps I like to be on the safe side of things

With PSU designerII I get with 15V toroid a regular bridge, 220mF stubby (11.7mOhm) and a 8Ohm load a peak of 250A , hence my question

You need to use some form of inrush limiter.
Here is what Mr. Pass suggests

 

[diyman]

Rectifiers

Anyone compared the sound of Schottky rectifiers to the MUR series? I have the Philips TO220 Schottky PBYR10100 rated at 100V 10A in mind. With adequate heatsinking, I think the voltage and current are good enough for the Aleph-X at +/- 22V and this item is fairly cheap.

ckt

 

[rwagter]

I know about de inrush limiters , I also use them in my Aleph5, but how can I calculate what the maximum inrush will be then, is it limited by the NTC's specs (5A in this case ?) or will it just notch the current ?

 

[roddyama]

Re: Rectifiers

Anyone compared the sound of Schottky rectifiers to the MUR series? I have the Philips TO220 Schottky PBYR10100 rated at 100V 10A in mind. With adequate heatsinking, I think the voltage and current are good enough for the Aleph-X at +/- 22V and this item is fairly cheap.

ckt

Here is an extensive discussion on PSU diodes.

I know about de inrush limiters , I also use them in my Aleph5, but how can I calculate what the maximum inrush will be then, is it limited by the NTC's specs (5A in this case ?) or will it just notch the current ?

The CL 60 has a cold resistance of ~10ohms. It suggested that these be used in each of the 120VAC primaries that would make up your 240VAC or if you don't have this type of transformer, use 2 - CL 60's in series to effectively give you ~20ohms at power up. This will limit the primaries to 240/20 = 12A. Or as Peter suggests, use the CL 70 with a cold resistance of 15ohms.

 

[KevinLee]

Hello,

Fairchild's new 'Stealth' diodes are available in to-220 package 30 amp rating. I have used these and they are quite good.

I have also tried On-Semi's new soft recovery diodes and they were no good for my needs, I yanked them and replaced with the Fairchilds.

Thanks

KevinLee

 

[rwagter]

Hi kevinlee,

do you have a partnumber on those stealth diodes and where did you buy them

 

[KevinLee]

Hello,

I ordered the parts from fairchild as samples. I do not have the part number handy but you can search their site for 'stealth' and you will find some.

Good luck

KevinLee

 

[rwagter]

Found it !!, now hopefully they will send me 20 pcs

 

[hacknet]

please don`t abuse the system....

 

[Mad_K]

I'm afraid that nice little pcb will burn under the punishment of the current draw of an AX combined with the voltage drop of the stealth-diodes...

 

[KevinLee]

Hello,

What do you mean by voltage drop? The diodes will be configured as a bridge.

I know the input voltage will increase by a factor of 1.4.

Peranders will know if his circuit traces can handle 30 amp draw.

KevinLee

 

[Mad_K]

I mean Vf, the forward voltage drop of for example ISL9R3060P2 under 8A current draw is something like 1-1,5V. Assuming chassi-temp of 50'C this translates to 1,25V*8A=10W*13'C/W=130'C+50'C=180'C heatsinktemp. And they're 175'C devices

 

[Nelson Pass]

We are currently using the ST Micro BYW99W-200, which is
a dual "high efficiency, fast recovery" 35 amp diode at 200
volts, and have been very happy with it.

It's remarkable for us to have converted to exotic rectifiers,
as we previously were very sceptical, but we did find a distinct
sonic improvement, and they also made it easier to meet
RF noise emission standards.

 

[Mad_K]

That's interesting... TO-247 case. They are about twice as efficient as the StealthTM diodes from Fairchild. But how do you configure a bridge with dual diodes with common Cathode? And how do you mount them?

 

[Nelson Pass]

We treat them as a single diode by paralleling them.

 

[UrSv]

I mean Vf, the forward voltage drop of for example ISL9R3060P2 under 8A current draw is something like 1-1,5V. Assuming chassi-temp of 50'C this translates to 1,25V*8A=10W*13'C/W=130'C+50'C=180'C heatsinktemp. And they're 175'C devices

Quite, but does the diode not conduct only half the time meaning half this dissipation?

 

[rwagter]

And I can always attach them wil L-profiles to my main heatsinking which is rather overdone for future upgrades, thus making the heatsink <0.3 C/W