Small SMPS problem

MaXiZ · 3rd January 2004, 12:59 PM

Hi to all i've just build another SMPS for my power amp project but i'venoticed that che voltage goes up slowly at the output after the caps and the current take from the circuit is very low.. why? maybe a low frequency set? Or maybe a transformer problem?

subwo1 · 3rd January 2004, 02:23 PM

One reason could be that you have too many turns n the primary.

MaXiZ · 3rd January 2004, 06:31 PM

i've build just 4 turns...
Turn of 4 wire of 0.5mm of diameter

subwo1 · 3rd January 2004, 07:21 PM

Another possibility would be if the pulse width is not getting close enough to 50% at full power output.

MaXiZ · 4th January 2004, 08:44 AM

and how can i solve it?

MaXiZ · 4th January 2004, 10:24 AM

mybe becouse i've used a 56ohm/4watt resistor instead of 56ohm/2watt resistor?

Workhorse · 4th January 2004, 10:42 AM

Connect a Resistor of 10K at the output of each gate driver to ground and connect 5.6K resistors at the both outputs of modulator to +12V

ddog · 4th January 2004, 10:53 AM

I can't be that you have used 4Watt resistors instead of 2Watt, power rating doesn't matter exept when you have too small power handling, then you will end up with lots of smoke

MaXiZ · 4th January 2004, 11:11 AM

Quote:

then you will end up with lots of smoke

???

Quote:

Connect a Resistor of 10K at the output of each gate driver to ground and connect 5.6K resistors at the both outputs of modulator to +12V

What's it's purpose?

Workhorse · 4th January 2004, 11:26 AM

Resistor at gate act as ground balancing and resistors at outputs act as collector load reference

3rd January 2004, 12:59 PM	#1
MaXiZ diyAudio Member Join Date: Jun 2003 Location: Italy	Small SMPS problem Hi to all i've just build another SMPS for my power amp project but i'venoticed that che voltage goes up slowly at the output after the caps and the current take from the circuit is very low.. why? maybe a low frequency set? Or maybe a transformer problem?

3rd January 2004, 02:23 PM	#2
subwo1 diyAudio Member Join Date: Jan 2002 Location: North American Continent	One reason could be that you have too many turns n the primary. __________________ USMPS http://groups.yahoo.com/group/switchmode/

3rd January 2004, 07:21 PM	#4
subwo1 diyAudio Member Join Date: Jan 2002 Location: North American Continent	Another possibility would be if the pulse width is not getting close enough to 50% at full power output. __________________ USMPS http://groups.yahoo.com/group/switchmode/

4th January 2004, 10:42 AM	#7
Workhorse diyAudio Member Join Date: Dec 2004	Reply Connect a Resistor of 10K at the output of each gate driver to ground and connect 5.6K resistors at the both outputs of modulator to +12V __________________ It's a fruitless endeavor to try and educate a fool that rejoices in ignorance

4th January 2004, 11:26 AM	#10
Workhorse diyAudio Member Join Date: Dec 2004	Reply Resistor at gate act as ground balancing and resistors at outputs act as collector load reference __________________ It's a fruitless endeavor to try and educate a fool that rejoices in ignorance


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3rd January 2004, 06:31 PM	#3
MaXiZ diyAudio Member Join Date: Jun 2003 Location: Italy	i've build just 4 turns... Turn of 4 wire of 0.5mm of diameter

4th January 2004, 08:44 AM	#5
MaXiZ diyAudio Member Join Date: Jun 2003 Location: Italy	and how can i solve it?

4th January 2004, 10:24 AM	#6
MaXiZ diyAudio Member Join Date: Jun 2003 Location: Italy	mybe becouse i've used a 56ohm/4watt resistor instead of 56ohm/2watt resistor?

4th January 2004, 10:53 AM	#8
ddog diyAudio Member Join Date: Oct 2003 Location: Finland	I can't be that you have used 4Watt resistors instead of 2Watt, power rating doesn't matter exept when you have too small power handling, then you will end up with lots of smoke

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