TPA3116 on 1 ohm load

[chriscam]

Hi all,

Searched for existing posts on the subject but couldn't find any so here goes, anybody here with experience boosting the 3116 max output current using external hbridged mosfets to allow 1 ohm loads ?

Am using 4 4ohm drivers and would like to parallel them.

 

[uriy-ch]

If you need a result, and not the process of achieving it, then put your own TPA3116 on each speaker and simply supply the same signal to the input of the TPAs themselves.

 

[pcan]

You will get 4 ohms by forming two series of 2 drivers each, and then parallel them.

 

[uriy-ch]

You will get 4 ohms by forming two series of 2 drivers each, and then parallel them.

With this solution, the control of the speaker by the amplifier will be reduced by at least half.

 

[chriscam]

Thanks for your speedy replies guys, much appreciated I'm aware 2 tpa's in pbtl would do the job but just wondered if anything like this has been tried before. Was thinking of using the tpa outputs to drive a pair of Automotive N- and P-Channel 40 V (D-S) 175 °C MOSFETs.

 

[uriy-ch]

For example, to open the N channel half, you need to apply a voltage to G that is 10V greater than the voltage to S. How are you going to do this using the TPA output?

 

[chriscam]

For example, to open the N channel half, you need to apply a voltage to G that is 10V greater than the voltage to S. How are you going to do this using the TPA output?

Was thinking of driving a P-N pair like below or would this mess up things like dead time ?

 

[uriy-ch]

Was thinking of using a P-N pair like below :

The keys will burn out if the supply voltage is more than 20V. There will also be an unacceptable through current through the power switches, since the switches will be open simultaneously when switching the control voltage.

 

[chriscam]

Ok, dead time issues, clear. Thx !

 

[Plopper]

I am running a 3116d2 bridged running a 1 ohm soundstream t5 12 inch sub. i also increased the gain to the 3116 and it has been running 5 years now and it is amazing how much bass it puts out. psu is Efore mpa160 24v 6a

 

[Freedom666]

@Plopper

Bridged?

Always Was reading not to use bridged class D amps with loads less than 4 ohm, 6 or 8 Ohm better.

Doesn't it get too hot on 1 ohm???

 

[mamocel]

Always Was reading not to use bridged class D amps

Most 4-channel TPA amplifiers are already bridged, which gives 2 BTL channels.
I think his amp is designed in mono PBTL. The TI doc documents all the ways to use the output stage.

 

[Plopper]

the amp has 2 3116's one in stereo one for the sub, so the sub amp must be bridged as it has only one output. driving a 1 ohm load puts .5 ohm on each channel of the one 3116 that drives the sub. playing music on the edge of going into protection it gets hot but not as hot as other amps i have. makes no sense how it works so good. i havent turned it off in 5 years either. passive cooling too.

 

[Freedom666]

@Plopper

Ok, thanks for the feedback.

Active cooling with a fan is more secure. But your setup shows it does not turn off even being driven hard at one ohm. Did not expect that.

 

[Plopper]

Great amp and cheap enough to destroy and try again. have fun

 

[Freedom666]

Really I am quite impressed by the sound quality of these small class D amps.

I tested the whuzi audio ones and it's so good enough that I do not think about something better.

https://www.diyaudio.com/community/threads/unboxing-zk-mt21-tpa3116.403857/#post-7518041

https://www.diyaudio.com/community/threads/difference-between-cs8673-and-tpa3116.405281/

https://www.diyaudio.com/community/threads/unboxing-zk-502mt-cs8673e.410107/#post-7623495

 

[WhiteDragon]

Its interesting that they survive at 1 ohm yet .5 ohms.

Im not sure what the benefit is though
1 ohm load is the worst load possible for any amp.
Easier to get voltage not waste so much heat in current.
Distortion be high at 4 ohms yet 2 then 1
ouch

4 ohms loads bother me
anything below it makes me cringe.

point is just build a amp with more voltage
swing

 

[Freedom666]

With so little load. Is there more distortion to be expected?

Is it this driver?

It has two coils with 2 ohm, so 4 ohm operation is possible

 

[Plopper]

MIne is the 12" T5.122 it has dual 2 ohm vc wired in parallel for 1 ohm rated at 1000wrms . it moves a lot of air through that port. its tuned to 30hz. I can remove the port and add different lengths to tune for any freq. I had this sub hooked up to my old Hafler xl280 (at 4 ohm) and after using the 3116 never went back. I'm sure the distortion is high but I can't tell at sub freq. After 5 years I am still amazed. I think I got the unicorn. I had it running my JL 10w7 at 3 ohm but it just didn't have the same output. It is a sealed enclosure, but I think it works best at 1ohm

 

[Freedom666]

The chip is protected in any way.

Did you manage to drive it into protection - heat for example?

Seems to be a robust design.

What power supply do you have? Amps, volts?