Simplistic Mosfet HV Shunt Regs - Page 91

Salas · 16th January 2010, 10:48 AM

Quote:

Originally Posted by guglielmope

The 2sk170 is ok!

Vg Irf840=0,01V

The 840 isn't opening? Is that one OK? Maybe a 8-12V Zener guarding its gate? Between ground and gate.

guglielmope · 16th January 2010, 11:22 AM

I'll try a new one.

Joshua_G · 17th January 2010, 01:18 AM

I looked for LEDs having known 1.7V on voltage. On mouser, only some red LEDs are rated 1.7V: LED, and this is the data sheet of one of those: http://www.kingbrightusa.com/images/.../WP7104LID.pdf, so I wonder if I miss anything?

iko · 17th January 2010, 01:27 AM

I usually prefer to use what I have on hand, and since I had lots of 2.1V LEDs, instead of two LEDs I used one LED and a resistor. The disadvantage is that one has to then optimize the value of the resistor. Perhaps it may work for you too though, if it ends up being problematic finding the 1.7V LEDs.

Joshua_G · 17th January 2010, 02:01 AM

Thanks.
I'm not sure if there's any problem, I'm only looking for known 1.7V LEDs.

quanghao · 18th January 2010, 04:51 AM

Hi Salas, Hi all!
I finis Salas shunt PCB, but my pCb is wrong, So I can sent them to you 5 gift now. I think I wil make it a gain, i sent it later for you!
Im very, very sorry about this PCb! Thank you!

Salas · 18th January 2010, 05:05 AM

Quote:

Originally Posted by guglielmope

I'll try a new one.

Any news with debugging it? Tried a new 840, checked all semis connections and orientations? Meanwhile, I got a suspicion that may when over 300V, those little -400V PNPs are struggling somehow. So I just thought that if it will not work on you with a single driver BJT, you may utilize some leftover MPSA92s for a cascode so to cut the dissipation and Vce in half. As a solution, it is even faster. If, it will not try to oscillate.

Salas · 18th January 2010, 05:27 AM

Quote:

Originally Posted by quanghao

Hi Salas, Hi all!
I finis Salas shunt PCB, but my pCb is wrong, So I can sent them to you 5 gift now. I think I wil make it a gain, i sent it later for you!
Im very, very sorry about this PCb! Thank you!

You do well you check because people if with a PCB, don't think twice, they put it to work. And here is high voltage. So no letter bomb gifts for now fellas.

stormsonic · 18th January 2010, 07:28 AM

schematic at post #891

Current passing through R5? (voltage drop on R5)
Vgs for IRF840 is only 20V

Salas · 18th January 2010, 11:18 AM

Just under 1mA. A transient could have passed during start up though. Gugliemo will give us more info about his debugging. Maybe he could also use a larger value trimmer just in case his 2SK170 has strong Idss.

18th January 2010, 04:51 AM	#906
quanghao diyAudio Member Join Date: Sep 2009 Location: Vietnam Blog Entries: 2	Hi Salas, Hi all! I finis Salas shunt PCB, but my pCb is wrong, So I can sent them to you 5 gift now. I think I wil make it a gain, i sent it later for you! Im very, very sorry about this PCb! Thank you! __________________ Group buy DAC-END R (ES9018) full assembled board update 21/5/2013 : https://docs.google.com/spreadsheet/...FE&hl=en#gid=0

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16th January 2010, 11:22 AM	#902
guglielmope diyAudio Member Join Date: Nov 2004 Location: Udine	I'll try a new one.

17th January 2010, 01:18 AM	#903
Joshua_G diyAudio Member Join Date: Nov 2008 Location: Israel	I looked for LEDs having known 1.7V on voltage. On mouser, only some red LEDs are rated 1.7V: LED, and this is the data sheet of one of those: http://www.kingbrightusa.com/images/.../WP7104LID.pdf, so I wonder if I miss anything?

17th January 2010, 01:27 AM	#904
iko diyAudio Moderator Join Date: May 2008 Location: Toronto	I usually prefer to use what I have on hand, and since I had lots of 2.1V LEDs, instead of two LEDs I used one LED and a resistor. The disadvantage is that one has to then optimize the value of the resistor. Perhaps it may work for you too though, if it ends up being problematic finding the 1.7V LEDs.

17th January 2010, 02:01 AM	#905
Joshua_G diyAudio Member Join Date: Nov 2008 Location: Israel	Thanks. I'm not sure if there's any problem, I'm only looking for known 1.7V LEDs.

18th January 2010, 07:28 AM	#909
stormsonic diyAudio Member Join Date: Aug 2008	schematic at post #891 Current passing through R5? (voltage drop on R5) Vgs for IRF840 is only 20V

18th January 2010, 11:18 AM	#910
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Just under 1mA. A transient could have passed during start up though. Gugliemo will give us more info about his debugging. Maybe he could also use a larger value trimmer just in case his 2SK170 has strong Idss.