I assume that will be connected to the mosfets switching output, right?
It is very smart, but have you tested that it triggers when there is PWM but it has a fixed duty cycle, different from 50%, that produces DC at the output that is dangerous enough for the speakers?
In that situation, the circuit should also trigger. This is unlikely and not related to output mosfet failure, but...
It is very smart, but have you tested that it triggers when there is PWM but it has a fixed duty cycle, different from 50%, that produces DC at the output that is dangerous enough for the speakers?
In that situation, the circuit should also trigger. This is unlikely and not related to output mosfet failure, but...
What I see Pierre is that he just try to mute output with a relay when there is no PWM signal...No protection at all here, just a mute..
Fredos
www.d-amp.com
Fredos
www.d-amp.com
wellcome all
this sch just like a mute function
but it's allmost can protect ur speaker connet to ucd or ucd_like amp
it base on the great design of ucd,🙂
i'll post some pics
to say it clearly
it depend on :when the pwm is off, it will take the speaker off the power amp
1.when ur fet are break,the pwm will be off
2. when ur input connet to the VDD(+50V), the output about 10v dc,and the pwm will be off
3. when daul the power is not the same No. dont worry that.
this sch just like a mute function
but it's allmost can protect ur speaker connet to ucd or ucd_like amp
it base on the great design of ucd,🙂
i'll post some pics
to say it clearly
it depend on :when the pwm is off, it will take the speaker off the power amp
1.when ur fet are break,the pwm will be off
2. when ur input connet to the VDD(+50V), the output about 10v dc,and the pwm will be off
3. when daul the power is not the same No. dont worry that.
this pic is when the power is +50v -25v
ucd is a great design, it can work on +50v -25v!
and the dc offset just +2v , it can't burn ur speakers
and u can hear the dis is very large,
this is a very Extreme State¡£
when the power is +50v -15v, the offset is 3v.
when the power is +50v -10v, the offset is 3.5v.
when the power is +50v -8v, the offset is 3.6v.
when the power is +50v -5v, the pwm is off
this is like that one of the FET is being Death (i dont know how to say it in english
)
ucd is a great design, it can work on +50v -25v!
and the dc offset just +2v , it can't burn ur speakers
and u can hear the dis is very large,
this is a very Extreme State¡£
when the power is +50v -15v, the offset is 3v.
when the power is +50v -10v, the offset is 3.5v.
when the power is +50v -8v, the offset is 3.6v.
when the power is +50v -5v, the pwm is off
this is like that one of the FET is being Death (i dont know how to say it in english
)Attachments
but sometimes it cant protect.
if u connet a 30k from input to vdd.
the pwm is on,but the output offset is 10v, is ham to ur speaker.
so, u must to insert a cap on the input pin.
if u connet a 30k from input to vdd.
the pwm is on,but the output offset is 10v, is ham to ur speaker.
so, u must to insert a cap on the input pin.
i use this sch in my mcd, and i have burn about 30 fets,but no harm to my speakers (a pair of Tannoy)
the full protection of class-d
i have test it in this mcd:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=93787
it can be working well with any class-d amp
to change the r/r control the max output.
i have test it in this mcd:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=93787
it can be working well with any class-d amp
to change the r/r control the max output.
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