Overload and Short Circuit Protection

space2000 · 14th April 2008, 10:29 AM

hi, how to make Overload and Short Circuit Protection for amp?

thank you.

Andy L. Francis · 14th April 2008, 11:13 AM

Check this paper! (See attachement!)

Kostya-M · 14th April 2008, 12:08 PM

Andy L. Francis, good article!

I prefer not use emitter resistors, if possible. In this time I place collector resistors and sensor with SOA approximation. After follows trigger on two transistors and switch, which shutdowns driver.

Andy L. Francis · 1st May 2008, 01:58 PM

Anyone has more design notes for OP protection circuits?
I'm interested. Thanks.

Billys8 · 23rd February 2009, 02:20 PM

Anybody?

Kostya-M · 23rd February 2009, 02:50 PM

This is sample of SOA protection. This variant don't affect on sound of amplifier

Samuel Jayaraj · 23rd February 2009, 04:53 PM

I'd be interested in getting any information possible on protection circuits (short-circuit protection & over-current protection) for QUASI output stage. Thanks.

Billys8 · 24th February 2009, 09:51 AM

Kostya-M, how can we use this? Can you help us describe us how it works?

Thank you in advance.

Kostya-M · 24th February 2009, 11:32 AM

If current throw output transistor (VT15/16) is high, voltage on sense resistor 0.1 Ohm opens transistor VT18 or VT22. Circuit with resistors 50-59 and zenners varies open current as to limit power dissipation on output transistors. VT19-21 - trigger. It opens VT17 and VT23. Its must switch off driver’s cascade.

Billys8 · 28th February 2009, 08:36 AM

Kostya-M, thank you for your answer.

I cannot understand how it works. I am confused about how it will sense the overload and how i will set it for specific transistors.
I guess that this is a sample, as you wrote, do you have a schematic more specific?
I think that this could be help me more.

Thank you.

14th April 2008, 10:29 AM	#1
space2000 diyAudio Member Join Date: Mar 2008	Overload and Short Circuit Protection hi, how to make Overload and Short Circuit Protection for amp? thank you.

23rd February 2009, 04:53 PM	#7
Samuel Jayaraj diyAudio Member Join Date: May 2001 Location: Bangalore, India	I'd be interested in getting any information possible on protection circuits (short-circuit protection & over-current protection) for QUASI output stage. Thanks. __________________ Sam

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14th April 2008, 12:08 PM	#3
Kostya-M diyAudio Member Join Date: Jun 2005 Location: Korolev near Moscow	Andy L. Francis, good article! I prefer not use emitter resistors, if possible. In this time I place collector resistors and sensor with SOA approximation. After follows trigger on two transistors and switch, which shutdowns driver.

1st May 2008, 01:58 PM	#4
Andy L. Francis diyAudio Member Join Date: Feb 2008	Anyone has more design notes for OP protection circuits? I'm interested. Thanks.

23rd February 2009, 02:20 PM	#5
Billys8 diyAudio Member Join Date: Oct 2008	Anybody?

24th February 2009, 09:51 AM	#8
Billys8 diyAudio Member Join Date: Oct 2008	Kostya-M, how can we use this? Can you help us describe us how it works? Thank you in advance.

24th February 2009, 11:32 AM	#9
Kostya-M diyAudio Member Join Date: Jun 2005 Location: Korolev near Moscow	If current throw output transistor (VT15/16) is high, voltage on sense resistor 0.1 Ohm opens transistor VT18 or VT22. Circuit with resistors 50-59 and zenners varies open current as to limit power dissipation on output transistors. VT19-21 - trigger. It opens VT17 and VT23. Its must switch off driver’s cascade.

28th February 2009, 08:36 AM	#10
Billys8 diyAudio Member Join Date: Oct 2008	Kostya-M, thank you for your answer. I cannot understand how it works. I am confused about how it will sense the overload and how i will set it for specific transistors. I guess that this is a sample, as you wrote, do you have a schematic more specific? I think that this could be help me more. Thank you.

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