Hi Sander,
Yeah we manufacture pro-amps for addressing large public gatherings...but some folks also use our amps in there home theatre systems to power up their subs to blast their houses and made their neighbours into run.....
The pictures you have seen must be some of our obsolete Class-AB amps....which are no longer in productions.....Our current range include Class-D and Class-AB NVMOS only.....
K a n w a r😀
Yeah we manufacture pro-amps for addressing large public gatherings...but some folks also use our amps in there home theatre systems to power up their subs to blast their houses and made their neighbours into run.....
The pictures you have seen must be some of our obsolete Class-AB amps....which are no longer in productions.....Our current range include Class-D and Class-AB NVMOS only.....
K a n w a r😀
LOL,
Sassen, Sounds like you have the hands on approach like me
If you come across a protection circuit that looks like it could actually work without intorducing more problems at high power then please let me know! I've spent many nights thinking of ways to protect things but all attempts have failed. I've gone through loads of pairs of FETs all with the same cause of death. Over current! either from speaker shorts or silly inputs ( usally caused by unplugging the RCA inputs live ).
I must say however, under normall operating conditions i've run the amp into a 200W 4R resistor clipping so hard it just shows a square wave on the scope at 10KHz at PK-PK around 60V ( over 100W RMS )for more than 10mins. Not only did the amp survive but it took the Wee Wee by staying cool!
Regards
Mad.P
Sassen, Sounds like you have the hands on approach like me
If you come across a protection circuit that looks like it could actually work without intorducing more problems at high power then please let me know! I've spent many nights thinking of ways to protect things but all attempts have failed. I've gone through loads of pairs of FETs all with the same cause of death. Over current! either from speaker shorts or silly inputs ( usally caused by unplugging the RCA inputs live ).
I must say however, under normall operating conditions i've run the amp into a 200W 4R resistor clipping so hard it just shows a square wave on the scope at 10KHz at PK-PK around 60V ( over 100W RMS )for more than 10mins. Not only did the amp survive but it took the Wee Wee by staying cool!
Regards
Mad.P
Nitrate,
Well, yes, I simulate/calculate things first, but then just don't sit back and marvel at my creation but start thinking of ways how during use it could be made to fail, and test these out on the prototype. Short-circuiting outputs is a far too common occurance to simply ignore for example. I do believe simulation and calculus are a great way to get a amplifier designed and up and running, the proof of the pudding for me is still in the actual measurements of a prototype and of course a close examination of under what conditions it might fail.
If I come across anything that's working and doesn't interfere with the amplifier too much I'll be sure to let you know. Currently I'm using a LM2941 regulator that has a TTL compatible on/off pin. I use sense resistors in the power supply lines and a simple transistor stage to boost the output to logic levels. The LM2941 powers the driver IC (IR2011) and hence when a overcurrent is detected it simply switches off the power to the driver IC. DC protection is implemented by measuring the output and having two relays in the power supply switching off both rails. Similar to Hypex, but designed differently.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Well, yes, I simulate/calculate things first, but then just don't sit back and marvel at my creation but start thinking of ways how during use it could be made to fail, and test these out on the prototype. Short-circuiting outputs is a far too common occurance to simply ignore for example. I do believe simulation and calculus are a great way to get a amplifier designed and up and running, the proof of the pudding for me is still in the actual measurements of a prototype and of course a close examination of under what conditions it might fail.
If I come across anything that's working and doesn't interfere with the amplifier too much I'll be sure to let you know. Currently I'm using a LM2941 regulator that has a TTL compatible on/off pin. I use sense resistors in the power supply lines and a simple transistor stage to boost the output to logic levels. The LM2941 powers the driver IC (IR2011) and hence when a overcurrent is detected it simply switches off the power to the driver IC. DC protection is implemented by measuring the output and having two relays in the power supply switching off both rails. Similar to Hypex, but designed differently.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Hi Kanwar
I will have a look at the e-mails again to see how the NFB actually was dimensioned.
Regards
Charles
I will have a look at the e-mails again to see how the NFB actually was dimensioned.
Regards
Charles
Sander,
Do you implement any power supply voltage guard or anything similar, for instance to ensure proper high side driver capacitor charging before switching starts?
I am interested in seeing your schematic for whatever you have implemented as I also have come up with the idea of using a 555.
/Daniel
Do you implement any power supply voltage guard or anything similar, for instance to ensure proper high side driver capacitor charging before switching starts?
I am interested in seeing your schematic for whatever you have implemented as I also have come up with the idea of using a 555.
/Daniel
One way to detect clipping is via a retriggerable monoflop. The output of the comparator retriggers it every time when the signal is going from low to high (or vice-versa depending on implementation). So it will stay in the metastable state if the time-constant is set accordingly. A soon as the transistions stop (which will happen during clipping) it will return to the stable state which can then be displayed. Maybe a second monoflop should be used to turn on the indicator long enough to be visually perceived.
The output of the first monoflop can also be used to control a VCA (after soem processing of course).
Regards
Charles
The output of the first monoflop can also be used to control a VCA (after soem processing of course).
Regards
Charles
Hi everyone,
I have seen something else in another reputed Class-D amp....That amp restricts the input of amplifier with VCA before its output voltage reaches the threshold of clipping..thereby it never clips in reality....Thus the output never touches its power rails..its voltage output remains just below 2 volts of supply rails.
regards,
K a n w a r
I have seen something else in another reputed Class-D amp....That amp restricts the input of amplifier with VCA before its output voltage reaches the threshold of clipping..thereby it never clips in reality....Thus the output never touches its power rails..its voltage output remains just below 2 volts of supply rails.
regards,
K a n w a r
Hi,
I still thinking about clipping in class-D too.
Let say that voltage rail is 50V, hence the class-AB will clip at 50V minus voltage drops.
Can the output voltage of class-d reach as high as class-AB before clipping occur? (Consider to the pulse width, t-on/t-off time, dead time, length of mosfet on-off etc.)
Thanks
kartino
I still thinking about clipping in class-D too.
Let say that voltage rail is 50V, hence the class-AB will clip at 50V minus voltage drops.
Can the output voltage of class-d reach as high as class-AB before clipping occur? (Consider to the pulse width, t-on/t-off time, dead time, length of mosfet on-off etc.)
Thanks
kartino
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