uPC1237/NTE7100

d3imlay · 20th December 2007, 07:46 PM

There have been some recent posts on these chips. Apparently the uPC has a few different versions, most of which are obsolete or will be soon. One post mentioned that of the 4 NTE's he got from China, 3 were bad. I wouldn't mind using the NTE but it only goes to a 60 VDC rail and I need to go to at least 80 and preferably 100VDC.

At the moment I'm playing with a variation of the common discreet circuits. Most of them have some kind of a detection circuit based around a couple transistors or a bridge rectifier that drives a couple transistors. I'd like to use a chip rather than a bunch of discreets as board space is very limited.

So I wonder, what chip is in common use these days? Certainly all of the surround receivers use something that is current.

EchoWars · 21st December 2007, 09:45 AM

I may be wrong, but I believe many (most?) modern protection is handled by a chip which also provides a host of other functions as well.

I'd consider Rod Elliot's board (it's very small), since integrated solutions seem to be disappearing.

According to the data sheet, the uPC1237 is also limited to 60V.

d3imlay · 21st December 2007, 11:04 AM

Quote:

Originally posted by EchoWars

I'd consider Rod Elliot's board (it's very small), since integrated solutions seem to be disappearing.

According to the data sheet, the uPC1237 is also limited to 60V.

I like and have use Rod's board (his project #33). However I have a specific application and will be building up a board that have the relay(s) mounted on the board. I emailed Rod about licensing his circuit but he didn't respond. Although his board is good, component spacing is so tight that solder bridges are a real concern. This problem is magnified as he doesn't use a solder mask.

EchoWars · 22nd December 2007, 08:59 AM

Well, I know you've used it because we've discussed it. Rod apparently had three design goals...simplicity, small size, and low cost. The latter is likely why there's no solder mask.

I wish I could help out, but I have next-to-no idea what the new stuff is using.

janneman · 22nd December 2007, 11:15 AM

Quote:

Originally posted by EchoWars
I may be wrong, but I believe many (most?) modern protection is handled by a chip which also provides a host of other functions as well.

I'd consider Rod Elliot's board (it's very small), since integrated solutions seem to be disappearing.

According to the data sheet, the uPC1237 is also limited to 60V.

I use the uPC1237 myself, I have no problems buying them from my local supplier. It works exactly as described in the data sheet. You need to figure out some resistor values if you want symmetrical offset protection. I use one uPC per channel as they are so cheap and it helps to keep channels and channel wiring separate.

Indeed it is limited to 60V but that should be trivially easly fixed with a couple of resistors. Just make sure the supply to the chip never gets above 60V.

Jan Didden

d3imlay · 22nd December 2007, 12:26 PM

Quote:

Originally posted by janneman

I use the uPC1237 myself, I have no problems buying them from my local supplier. It works exactly as described in the data sheet. You need to figure out some resistor values if you want symmetrical offset protection. I use one uPC per channel as they are so cheap and it helps to keep channels and channel wiring separate.

Indeed it is limited to 60V but that should be trivially easly fixed with a couple of resistors. Just make sure the supply to the chip never gets above 60V.

Jan Didden

I was thinking about that. A 30 volt zener from the 80V power supply would get below 60V. Are you thinking of using a voltage divider on the input to limit the voltage.

paulb · 22nd December 2007, 12:41 PM

I plan to use the NTE7100 and my breadboard version seems to work okay. I plan to use a simple dropping resistor as shown in the UPC1237 datasheet.

janneman · 22nd December 2007, 06:24 PM

Quote:

Originally posted by d3imlay

I was thinking about that. A 30 volt zener from the 80V power supply would get below 60V. Are you thinking of using a voltage divider on the input to limit the voltage.

You want to limit the supply of course, not the input voltage. I think paulb above answered it.

Jan Didden

loek · 17th February 2008, 08:03 PM

Hello Jan, YGM.
Greetings, Loek

zeonrider · 17th February 2008, 08:22 PM

Don't wast time here is complet!

Regards zeoN_Rider

20th December 2007, 07:46 PM	#1
d3imlay diyAudio Member Join Date: Sep 2004 Location: Ohio	uPC1237/NTE7100 There have been some recent posts on these chips. Apparently the uPC has a few different versions, most of which are obsolete or will be soon. One post mentioned that of the 4 NTE's he got from China, 3 were bad. I wouldn't mind using the NTE but it only goes to a 60 VDC rail and I need to go to at least 80 and preferably 100VDC. At the moment I'm playing with a variation of the common discreet circuits. Most of them have some kind of a detection circuit based around a couple transistors or a bridge rectifier that drives a couple transistors. I'd like to use a chip rather than a bunch of discreets as board space is very limited. So I wonder, what chip is in common use these days? Certainly all of the surround receivers use something that is current.

17th February 2008, 08:03 PM	#9
loek diyAudio Member Join Date: Feb 2005 Location: The Hague	upc1237 Hello Jan, YGM. Greetings, Loek

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21st December 2007, 09:45 AM	#2
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	I may be wrong, but I believe many (most?) modern protection is handled by a chip which also provides a host of other functions as well. I'd consider Rod Elliot's board (it's very small), since integrated solutions seem to be disappearing. According to the data sheet, the uPC1237 is also limited to 60V.

22nd December 2007, 08:59 AM	#4
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	Well, I know you've used it because we've discussed it. Rod apparently had three design goals...simplicity, small size, and low cost. The latter is likely why there's no solder mask. I wish I could help out, but I have next-to-no idea what the new stuff is using.

22nd December 2007, 12:41 PM	#7
paulb diyAudio Member Join Date: Jun 2001 Location: Calgary	I plan to use the NTE7100 and my breadboard version seems to work okay. I plan to use a simple dropping resistor as shown in the UPC1237 datasheet.

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