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Re: little bit O.T IGBT doesn't need snubber

 

Bert,

The recent "design ideas" discussion led me to an announcement of a IGBT
that does not require a snubbing circuit
There have been IGBTs out there for quite some time, that clamp overvoltage not by avalanching in the main device, but by intentionally turning the device partially on, by means of a zener diode between collector and gate. It's not a new thing.

Prime examples of such devices are the IGBTs used in engine ignition systems. See the datasheet of the STGB20NB37LZ, to learn about it.

It makes perfect sense to extend this technique to higher frequency operation, in switching power supplies.

It's true, of course, that there will be more power dissipation in the IGBT, than when using a snubber. But who cares? What matters to a manufacturer is getting the job done at the lowest possible cost. If a snubberless IGBT mounted on a slightly larger heatsink is cheaper than a plain IGBT mounted on a smaller heatsink plus a power resistor, high voltage capacitor and fast diode, they will go for it. And typically the overall efficiency is better when using such a clamped IGBT, than when using a snubber, because the IGBT clamps just the necessary minimal amount, while a conventional snubber also consumes some energy when the voltage is well inside the allowed range.

Manfred

========================
Visit my hobby homepage!

========================
Re: 7704A -just a quickie

 

Hi,

p20G 7 to 9 should be a very small resistance but not zero. This the lamp circuit. The readings you gave look okay. Add 2 ohms from the +5v line to ground and see if the 7704a will power up.

Jerry Massengale

-----Original Message-----
From: Keith Smith kahsmith@... [TekScopes] <TekScopes@...>
To: TekScopes <TekScopes@...>
Sent: Sun, Dec 14, 2014 11:54 pm
Subject: Re: [TekScopes] 7704A -just a quickie






HI Jerry,
It's all in the spreadsheet but it pretty much boils down to this:
P20G3 Ground
P20G6, -50v, 13.2k
P20G1, -15v, 124¦¸
P20G2, +5v, 86¦¸
P20G4, +15v, 124¦¸
P20G5, +50, 1.7k
These were pretty consistent though all the boards, except the +50 was a
lot higher on the 41 & 42 boards (P41i3 and P42i3) at 18.8k.

400¦¸ was on the +15v, I think. I just quickly tried that expecting a
greater change with the boards disconnected, so I didn't write it down.
I can't probably duplicate that right now because I have the A24 trigger
board removed to get at those caps.
The in-circuit Resistance across C2085 was 350¦¸ -probably doesn't mean
much(?).
I forgot to mention in the above post that no plugins were installed,
because I wanted to get at the slot pins for continuity testing.

On Sun, Dec 14, 2014 at 9:20 PM, jerry massengale j_massengale@...
[TekScopes] <TekScopes@...> wrote:




Hi,

Please give the measured resistance from all the low voltage power outputs
to ground and what plugins were present if any. This a ballpark value but
the +5v should be less than 100 ohms the +-15v should be 100 to 200 ohms or
so, the +- 50v should be higher than the 15v lines. The +5Vlight line will
be less than 10 ohms depending on what is connected.

Where do you get 400ohms for C2085?

Jerry Massengale

-----Original Message-----
From: Keith Smith kahsmith@... [TekScopes] <
TekScopes@...>
To: TekScopes <TekScopes@...>
Sent: Sun, Dec 14, 2014 7:34 pm
Subject: Re: [TekScopes] 7704A -just a quickie

Well, I'm getting some time in on this today. During the week I made a
spreadsheet to help me get a grip on all of the inter-connects for at least
the +50, -50, +15, -15, and +5v supplies.
That allowed me to work through it all fairly quickly and hopefully I
haven't missed too much in the process. I still have Magnus' "Do it
thoroughly." ringing in my ears.



I checked for continuity with the power supply removed entirely, starting
from the P20G connector pins to all of the other boards and found no
problems.

This may be contentious: I've acquired a couple of Huntron Trackers (1000 &
2000) that were thrown in with a couple of scopes some time ago. I've never
seen them mentioned here and would be interested to read any opinions on
their efficacy.
I used the Huntron 2000 for the continuity tests. I liked the indication of
whether the circuit being tested appears to be totally resistive or if some
other function is going on. I'm certainly not suggesting I possess any
expertise in its use.
All supply paths tested looked purely resistive, as expected.

Assuming that the PS is in tick mode due to an overcurrent problem, I
started looking for shorts.

I checked the resistance to ground (Pin 3 of P20G) of all the interconnect
points and added those values to the spreadsheet. Measurements were made
with a Fluke 87V.
The low R values of the +/-15 and +5 v supplies quickly indicated a
problem, I think, and were repetitive throughout the system ,but I followed
through for the sake of completeness.
Later, I checked R values from P20G-3 to the supplies on pins 1, 2 and 4,
while I disconnected the A10, A33, A34 boards and the entire Display unit.
The highest value I could get was about 400 Ohms (suspiciously close to the
in-circuit resistance of C2085).

I find the symmetry of the R values on both 15v supplies a bit curious.
Could be a clue?

I'm guessing the next thing is likely the C2081/83/85/87 caps, which all
look to be tantalum. I don't have an ESR meter, but I do have a Schmitt
trigger built from Alan Wolke's (W2AEW) video, so I could pull them and try
to get a rough ESR value on a scope. It might be quicker to just replace
them though. I can probably get them tomorrow at my local supply house. Any
suggestions on suitable replacements would be appreciated.

For what it's worth, 85 & 87 have nice fat ellipses on the Huntron, while
81& 83 look pencil thin even at 60 Hz.
Whatever is going on, I'm feeling it's probably on the A20 board or its
close cousins. Make sense?

Thanks again!
Keith



[Non-text portions of this message have been removed]


--
Keith Smith - KeithSmith.ca_Freelance Guitarist & Location Recording Service
<>;
Re: tek 465 no sweep question

 

Power supply voltages in test points are in tolerance.
+5v reads 4.99v
Re: tek 465 no sweep question

 

Power supply test points? Especially the +5.


Tom

----- Original Message -----
From: sk_circuits@... [TekScopes]
To: TekScopes@...
Sent: Monday, December 15, 2014 1:43 AM
Subject: [TekScopes] tek 465 no sweep question



Hello to all the group members.

My tek 465 stopped working recently and I'm trying to find the offending circuit.
There is no horizontal trace on both channels on standard settings with auto triggering selected.
I can see a dot with beam finder button pushed but no trace.
In x-y mode the dot is visible and both x and y can be adjusted.
However both traces are visible (two solid lines) in 'chop' mode, but both disappear when I'm adjusting vertical position pots or any switch.

I don't have another scope to measure waveforms from the service manual so I followed the troubleshooting flow chart for the 'no trace' case and measured dc voltages on q1024 and u870 sweep logic chip.

q1024:
collector -0.2v (-1.7v in service manual)
emitter -4.6 OK
base -4v OK

u870 has incorrect voltages on some pins:
pin6 (auto rc) -0.3v (+5.2v in service manual)
pin17 (swp disable) -0.2v (+0.3 in manual)
pin19 (auto) 0v (+2.5v in manual)

All other pin voltages are in spec.


So now I'm stuck. Is it u870 fried or some other faulty component prevents it from working?
I could start desoldering transistors on the sweep/trigger board, but I don't fully grasp how the whole sweep circuit works so it would be a blind search.

Any help would be highly appreciated.

Thanks,
Serge.
tek 465 no sweep question

 

Hello to all the group members.

My tek 465 stopped working recently and I'm trying to find the offending circuit.
There is no horizontal trace on both channels on standard settings with auto triggering selected.
I can see a dot with beam finder button pushed but no trace.
In x-y mode the dot is visible and both x and y can be adjusted.
However both traces are visible (two solid lines) in 'chop' mode, but both disappear when I'm adjusting vertical position pots or any switch.

I don't have another scope to measure waveforms from the service manual so I followed the troubleshooting flow chart for the 'no trace' case and measured dc voltages on q1024 and u870 sweep logic chip.

q1024:
collector -0.2v (-1.7v in service manual)
emitter -4.6 OK
base -4v OK

u870 has incorrect voltages on some pins:
pin6 (auto rc) -0.3v (+5.2v in service manual)
pin17 (swp disable) -0.2v (+0.3 in manual)
pin19 (auto) 0v (+2.5v in manual)

All other pin voltages are in spec.


So now I'm stuck. Is it u870 fried or some other faulty component prevents it from working?
I could start desoldering transistors on the sweep/trigger board, but I don't fully grasp how the whole sweep circuit works so it would be a blind search.

Any help would be highly appreciated.

Thanks,
Serge.
Re: 7704A -just a quickie

 

HI Jerry,
It's all in the spreadsheet but it pretty much boils down to this:
P20G3 Ground
P20G6, -50v, 13.2k
P20G1, -15v, 124¦¸
P20G2, +5v, 86¦¸
P20G4, +15v, 124¦¸
P20G5, +50, 1.7k
These were pretty consistent though all the boards, except the +50 was a
lot higher on the 41 & 42 boards (P41i3 and P42i3) at 18.8k.

400¦¸ was on the +15v, I think. I just quickly tried that expecting a
greater change with the boards disconnected, so I didn't write it down.
I can't probably duplicate that right now because I have the A24 trigger
board removed to get at those caps.
The in-circuit Resistance across C2085 was 350¦¸ -probably doesn't mean
much(?).
I forgot to mention in the above post that no plugins were installed,
because I wanted to get at the slot pins for continuity testing.

On Sun, Dec 14, 2014 at 9:20 PM, jerry massengale j_massengale@...
[TekScopes] <TekScopes@...> wrote:




Hi,

Please give the measured resistance from all the low voltage power outputs
to ground and what plugins were present if any. This a ballpark value but
the +5v should be less than 100 ohms the +-15v should be 100 to 200 ohms or
so, the +- 50v should be higher than the 15v lines. The +5Vlight line will
be less than 10 ohms depending on what is connected.

Where do you get 400ohms for C2085?

Jerry Massengale

-----Original Message-----
From: Keith Smith kahsmith@... [TekScopes] <
TekScopes@...>
To: TekScopes <TekScopes@...>
Sent: Sun, Dec 14, 2014 7:34 pm
Subject: Re: [TekScopes] 7704A -just a quickie

Well, I'm getting some time in on this today. During the week I made a
spreadsheet to help me get a grip on all of the inter-connects for at least
the +50, -50, +15, -15, and +5v supplies.
That allowed me to work through it all fairly quickly and hopefully I
haven't missed too much in the process. I still have Magnus' "Do it
thoroughly." ringing in my ears.



I checked for continuity with the power supply removed entirely, starting
from the P20G connector pins to all of the other boards and found no
problems.

This may be contentious: I've acquired a couple of Huntron Trackers (1000 &
2000) that were thrown in with a couple of scopes some time ago. I've never
seen them mentioned here and would be interested to read any opinions on
their efficacy.
I used the Huntron 2000 for the continuity tests. I liked the indication of
whether the circuit being tested appears to be totally resistive or if some
other function is going on. I'm certainly not suggesting I possess any
expertise in its use.
All supply paths tested looked purely resistive, as expected.

Assuming that the PS is in tick mode due to an overcurrent problem, I
started looking for shorts.

I checked the resistance to ground (Pin 3 of P20G) of all the interconnect
points and added those values to the spreadsheet. Measurements were made
with a Fluke 87V.
The low R values of the +/-15 and +5 v supplies quickly indicated a
problem, I think, and were repetitive throughout the system ,but I followed
through for the sake of completeness.
Later, I checked R values from P20G-3 to the supplies on pins 1, 2 and 4,
while I disconnected the A10, A33, A34 boards and the entire Display unit.
The highest value I could get was about 400 Ohms (suspiciously close to the
in-circuit resistance of C2085).

I find the symmetry of the R values on both 15v supplies a bit curious.
Could be a clue?

I'm guessing the next thing is likely the C2081/83/85/87 caps, which all
look to be tantalum. I don't have an ESR meter, but I do have a Schmitt
trigger built from Alan Wolke's (W2AEW) video, so I could pull them and try
to get a rough ESR value on a scope. It might be quicker to just replace
them though. I can probably get them tomorrow at my local supply house. Any
suggestions on suitable replacements would be appreciated.

For what it's worth, 85 & 87 have nice fat ellipses on the Huntron, while
81& 83 look pencil thin even at 60 Hz.
Whatever is going on, I'm feeling it's probably on the A20 board or its
close cousins. Make sense?

Thanks again!
Keith

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]



--
Keith Smith - KeithSmith.ca_Freelance Guitarist & Location Recording Service
<>


[Non-text portions of this message have been removed]
Re: Tek 2465 A9 HV module interchangeability ?

 

Is there a problem with the -15 Unregulated supply? There is a 180 uF cap, C1113 that could be bad and let the voltage sag. Maybe that is the problem with your old A9 board. I could not find any reference to the part number of your old board. The -08 board is a later version and should work fine.

Check the -15 Unregulated level.

Regards

----- Original Message -----
From: spinstar56@... [TekScopes]
To: TekScopes@...
Sent: Sunday, December 14, 2014 10:59 PM
Subject: [TekScopes] Tek 2465 A9 HV module interchangeability ?



Hi there!


I have a 2465 with a bad A9 HV module--part# GB-7717-02.
I purchased another with a model# of 670-7277-08. This module was supposedly "removed from a working 2465" but seems to buckle the power-supply (i.e. the inverter loudly complains and all the front panel lights come on but never complete the power-on sequence). I was afraid to leave it on long enough to find out exactly which voltage is getting hammered but my intuition says the -15. The seller said it should be compatible...


Anyway, are these modules compatible and do you think I was sent a bad A9 module?


Thanks in Advance!
Re: Tek 2465 A9 HV module interchangeability ?

 

With your old A9 board inverter work well, and voltage levels are ok?
I have the same exact symptom some time in the past. Please check the + 10 v reference voltage, and if is at half f.e. 4,5 - 5v, then change a 11v zener diode on inverter board.

Panos.
Re: 7704A -just a quickie

 

Hi,

Please give the measured resistance from all the low voltage power outputs to ground and what plugins were present if any. This a ballpark value but the +5v should be less than 100 ohms the +-15v should be 100 to 200 ohms or so, the +- 50v should be higher than the 15v lines. The +5Vlight line will be less than 10 ohms depending on what is connected.

Where do you get 400ohms for C2085?

Jerry Massengale

-----Original Message-----
From: Keith Smith kahsmith@... [TekScopes] <TekScopes@...>
To: TekScopes <TekScopes@...>
Sent: Sun, Dec 14, 2014 7:34 pm
Subject: Re: [TekScopes] 7704A -just a quickie






Well, I'm getting some time in on this today. During the week I made a
spreadsheet to help me get a grip on all of the inter-connects for at least
the +50, -50, +15, -15, and +5v supplies.
That allowed me to work through it all fairly quickly and hopefully I
haven't missed too much in the process. I still have Magnus' "Do it
thoroughly." ringing in my ears.


I checked for continuity with the power supply removed entirely, starting
from the P20G connector pins to all of the other boards and found no
problems.

This may be contentious: I've acquired a couple of Huntron Trackers (1000 &
2000) that were thrown in with a couple of scopes some time ago. I've never
seen them mentioned here and would be interested to read any opinions on
their efficacy.
I used the Huntron 2000 for the continuity tests. I liked the indication of
whether the circuit being tested appears to be totally resistive or if some
other function is going on. I'm certainly not suggesting I possess any
expertise in its use.
All supply paths tested looked purely resistive, as expected.

Assuming that the PS is in tick mode due to an overcurrent problem, I
started looking for shorts.

I checked the resistance to ground (Pin 3 of P20G) of all the interconnect
points and added those values to the spreadsheet. Measurements were made
with a Fluke 87V.
The low R values of the +/-15 and +5 v supplies quickly indicated a
problem, I think, and were repetitive throughout the system ,but I followed
through for the sake of completeness.
Later, I checked R values from P20G-3 to the supplies on pins 1, 2 and 4,
while I disconnected the A10, A33, A34 boards and the entire Display unit.
The highest value I could get was about 400 Ohms (suspiciously close to the
in-circuit resistance of C2085).

I find the symmetry of the R values on both 15v supplies a bit curious.
Could be a clue?

I'm guessing the next thing is likely the C2081/83/85/87 caps, which all
look to be tantalum. I don't have an ESR meter, but I do have a Schmitt
trigger built from Alan Wolke's (W2AEW) video, so I could pull them and try
to get a rough ESR value on a scope. It might be quicker to just replace
them though. I can probably get them tomorrow at my local supply house. Any
suggestions on suitable replacements would be appreciated.

For what it's worth, 85 & 87 have nice fat ellipses on the Huntron, while
81& 83 look pencil thin even at 60 Hz.
Whatever is going on, I'm feeling it's probably on the A20 board or its
close cousins. Make sense?

Thanks again!
Keith

[Non-text portions of this message have been removed]








[Non-text portions of this message have been removed]
Tek 2465 A9 HV module interchangeability ?

 

Hi there!


I have a 2465 with a bad A9 HV module--part# GB-7717-02.
I purchased another with a model# of 670-7277-08. This module was supposedly "removed from a working 2465" but seems to buckle the power-supply (i.e. the inverter loudly complains and all the front panel lights come on but never complete the power-on sequence). I was afraid to leave it on long enough to find out exactly which voltage is getting hammered but my intuition says the -15. The seller said it should be compatible...


Anyway, are these modules compatible and do you think I was sent a bad A9 module?


Thanks in Advance!
Re: 7704A -just a quickie

 

Well, I'm getting some time in on this today. During the week I made a
spreadsheet to help me get a grip on all of the inter-connects for at least
the +50, -50, +15, -15, and +5v supplies.
That allowed me to work through it all fairly quickly and hopefully I
haven't missed too much in the process. I still have Magnus' "Do it
thoroughly." ringing in my ears.


I checked for continuity with the power supply removed entirely, starting
from the P20G connector pins to all of the other boards and found no
problems.

This may be contentious: I've acquired a couple of Huntron Trackers (1000 &
2000) that were thrown in with a couple of scopes some time ago. I've never
seen them mentioned here and would be interested to read any opinions on
their efficacy.
I used the Huntron 2000 for the continuity tests. I liked the indication of
whether the circuit being tested appears to be totally resistive or if some
other function is going on. I'm certainly not suggesting I possess any
expertise in its use.
All supply paths tested looked purely resistive, as expected.

Assuming that the PS is in tick mode due to an overcurrent problem, I
started looking for shorts.

I checked the resistance to ground (Pin 3 of P20G) of all the interconnect
points and added those values to the spreadsheet. Measurements were made
with a Fluke 87V.
The low R values of the +/-15 and +5 v supplies quickly indicated a
problem, I think, and were repetitive throughout the system ,but I followed
through for the sake of completeness.
Later, I checked R values from P20G-3 to the supplies on pins 1, 2 and 4,
while I disconnected the A10, A33, A34 boards and the entire Display unit.
The highest value I could get was about 400 Ohms (suspiciously close to the
in-circuit resistance of C2085).

I find the symmetry of the R values on both 15v supplies a bit curious.
Could be a clue?

I'm guessing the next thing is likely the C2081/83/85/87 caps, which all
look to be tantalum. I don't have an ESR meter, but I do have a Schmitt
trigger built from Alan Wolke's (W2AEW) video, so I could pull them and try
to get a rough ESR value on a scope. It might be quicker to just replace
them though. I can probably get them tomorrow at my local supply house. Any
suggestions on suitable replacements would be appreciated.

For what it's worth, 85 & 87 have nice fat ellipses on the Huntron, while
81& 83 look pencil thin even at 60 Hz.
Whatever is going on, I'm feeling it's probably on the A20 board or its
close cousins. Make sense?

Thanks again!
Keith
Re: DC508 1GHz Counter

 

Thank you for all replies. It confirms what I suspected. I am missing the prescaler board. Henryk
Re: TEK 2465 with screen issues.

 

Hi guys. Finally responsible for the problem with dot characters, is the A5 digital control board.
I know cause I said "have tested" in the past, when I exchange this with another working from my 2445 oscilloscope. My main concern then, was the jittery crt and somehow I miss something about the other problem with readout dots. :-(


I think to check the eprom contents first. I have 4 of these on my board, and the marks are...


160-1625-06
160-1626-06
160-1627-06
160-1628-06


As you understand going for the version 6, which according with my serial number "B013759" on service manual.
I have found some newer version for later serial numbers, but no mine v6. Have anyone available this exact rom version?


Panos.
Re: 2335 vertical issues (2335/2336/2337 service manual needed)

Dave Casey
 

It is highly unlikely. Everything around it is biased and just waiting
on the push/pull of the preamp.

Dave Casey

On 12/14/2014 3:17 PM, system100m@... [TekScopes] wrote:

I have powered the unit up with no 155-0220-00 IC in channel 1 for a
minute, is it likely that any damage have happened to the unit ?
Re: DC508 1GHz Counter

 

Henryk
I think you are missing the prescaler box, which is to the left of the
main board (looking from the front) and mounted on standoffs from the
main board and to the frequency switch. The metal box (with a
perforated detachable top) is about 1/2" deep, 6" front to back and just
fits within the module top & bottom frames. If you want I can send
photos - email me off-list
Option 1 gives you a better spec timebase - but you already suspected
that from the 108A manual!
Chris HJ



I acquired DC508 counter Opt1. It works fine from direct input but 75-1GHz
input is not connected to the circuit. I couldn't find DC508 1GHz
manual. I
downloaded DC508A 1.3GHZ instead. The DC508A appears to have x3 PCB's:
main
board, resolution multiplier and prescaler.

My unit only have two boards:main board and resolution multiplier board.
The 75-1GHz BNC connector is not connected to anything. I wonder maybe the
difference between DC508 and 508A is in the prescaler board hence 1GHz vs
1.3GHz, just guessing.

Can anyone please confirm if this the case or I am missing the prescaler
board in my unit. The main boards appeares to be nearly identical.

Henryk
------------------------------------
Posted by: henasau@...
------------------------------------



No virus found in this message.
Checked by AVG - www.avg.com <>
Version: 2015.0.5577 / Virus Database: 4235/8735 - Release Date: 12/14/14
Re: DC508 1GHz Counter

 

Hi Henryk,

Option 1 is a better time base for the DC508 so that wouldn't account for
your missing board.
Unfortunately I only have DC508A so I can't help any further.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: Saturday, December 13, 2014 6:02 PM
To: TekScopes@...
Subject: [TekScopes] DC508 1GHz Counter

I acquired DC508 counter Opt1. It works fine from direct input but 75-1GHz
input is not connected to the circuit. I couldn't find DC508 1GHz manual. I
downloaded DC508A 1.3GHZ instead. The DC508A appears to have x3 PCB's: main
board, resolution multiplier and prescaler.

My unit only have two boards:main board and resolution multiplier board.
The 75-1GHz BNC connector is not connected to anything. I wonder maybe the
difference between DC508 and 508A is in the prescaler board hence 1GHz vs
1.3GHz, just guessing.

Can anyone please confirm if this the case or I am missing the prescaler
board in my unit. The main boards appeares to be nearly identical.

Henryk
------------------------------------
Posted by: henasau@...
------------------------------------
Re: 2335 vertical issues (2335/2336/2337 service manual needed)

 

I have powered the unit up with no 155-0220-00 IC in channel 1 for a minute, is it likely that any damage have happened to the unit ?
Re: 2335 vertical issues (2335/2336/2337 service manual needed)

 

OK so the acetone trick didn't work as far as it seems, but a replacement vertical preamp chip is on the way !

Thanks !
Re: Tek 335 Rear Feet

 

If you're near a fair sized city, look for few machine shops (real ones -
I wouldn't bother with the automotive guys), in the yellow pages. They
often get jobs that require Delrin, Nylon etc. and may have 'short ends'
they'll sell or even give to you.
Also these guys are often supplied by small quantity suppliers -the ones
who will batch cut to length etc., and they often have commonly used bits
of plastic around. Look for keywords like short ends, offcuts, etc..
This saves on minimums, shipping and develops a network of useful contacts.

Also, if you have a live steamers club in your area, you have some guys who
are just aching to do a little machine job and they collect all kinds of
materials. Many are highly skilled, retired toolmakers.
k
Re: little bit O.T IGBT doesn't need snubber

Stefan Trethan
 

Also you will dissipate the energy in the semiconductor instead of the
external snubber circuit.
I'm usually very happy to get even a little power dissipation away
from the switch.....

I think if you provide sufficient margin it would be no less reliable,
but even measuring avalanche energy is not that easy and many
designers will rather avoid it. Also there is the problem that the
avalanche mode is not always well specified (depends on the
manufacturer).

The EMC issue alone usually warrants the external snubber, but I am
not opposed to rely on avalanche for transient events.

ST

On Sun, Dec 14, 2014 at 7:10 PM, 'Paul Kraemer' elespe@...
[TekScopes] <TekScopes@...> wrote:
Our experience with devices in industrial control is most manufacturers use external circuit anyway, not trusting the built in approach of the semiconductor manufacturer
Paul

From: mailto:TekScopes@...
Sent: Sunday, December 14, 2014 10:05 AM
To: TekScopes@...
Subject: [TekScopes] little bit O.T IGBT doesn't need snubber


The recent "design ideas" discussion led me to an announcement of a IGBT
that does not require a snubbing circuit
when used in the typical offline flyback PS.
Supposedly it handles this on chip and to me this is one of those "why
doesn't everyone do it this way?" moments.
Searching on the listed part number led nowhere.
Has anyone worked with these?

Thanks,
Bert
96321 - 96340 of 208607