UCD 25 watts to 1200 watts using 2 mosfets

[andrewlebon]

LOAD TESTING

SOME TESTING PICS on 1500watt load
warm regards
andrew lebon

 

[Deleted member 148505]

i dont like jumpers
I think this is beter

An externally hosted image should be here but it was not working when we last tested it.

Jumpers are ok.
Why your suggestion is not good? Let's compare it.

1st jumper: is there so that the Logic Gnd (VSS) of CD4049 and Logic Gnd of IR2110 are referenced on the same point.

2nd jumper: the feedback is routed inside the IC instead of routing it along the "noisy" high side gate drive.

3rd jumper: minimizes the path/trace for the current loop in the low side gate drive.

Regards,
Lester

 

[Deleted member 148505]

HI
thanks for your sharing
why you and other engineer dont creat all things in one board ?
main board dont have OCP ?
for OCP i must creat protection board too ?
thanks

Yes you must create speaker protect with external trigger for it to work.

But I am doubting if the relay is fast enough for it to turn off before the mosfets blow.

I am thinking if this will work?
I will connect the trigger to the SD pin of IR2110, current and voltage will be limited by resistor and zener diode.

Any Ideas?
Thanks

 

[Deleted member 148505]

Oh, I realized that the SD pin should be connected to logic ground in normal operation, so the circuit above might not work.

I'll revise it

 

[Hadighorbani]

sir CPX say to me before the relay is not fast enofe.
i belive him
it is beter to you sir to creat every thing in one board and without relay
you is beter than me
thanks

 

[Hadighorbani]

thanks dear friend

Hadighorbani:
Use multisim 11 to open that file. Also you have a huge ground loop on that board and no snubers....

Hi sir CPX
how are you today friend ?
i am happy to see you again here.
thanks for your helping
have nice day

 

[Deleted member 148505]

I think it will be fast if the relay is a solid state/mosfet based.

I think I'll just add a daughter board that can be easily attached through pins.

 

[Hadighorbani]

I think it will be fast if the relay is mosfet based.

so expensive
and mosfet have enoufe power ?

 

[manojtm]

I think it will be fast if the relay is a solid state/mosfet based.

Hi Jlester87,

For DC protect we need 10ms fast is enough if your circuit detect <or=3v dc what i used is <10ms fast one and all other higher current(>10A) rated relays are 18ms fast.

for protecting MOSFET need OC circuit and use at least twice the current rated (25degree) FET.

Regards
MANOJ

 

[Deleted member 148505]

Hi Manoj,

Thanks for the info.

I have a Songchuan 801H-1C-S here, it has a 5ms release time. I'll check the SOA of IRFB4227 in its datasheet if it can survive 40A Current within 20ms(worst case).

Iraudamp1 also uses a mechanical relay for OCP, it has a 5ms release time according to its datasheet but it has no documentation for the response of OCP. (unlike IRAUDAMP9 and modified IRAUDAMP5 reference designs)

Regards,
Lester

 

[aman khalsa]

SOME TESTING PICS on 1500watt load
warm regards
andrew lebon

hello sir... this is amp or smps ?

 

[Deleted member 148505]

Max SOA for IRFP4227 is 30A at 70V(drain-source) for 100usec pulse duration.

5 ms is too long... protection should kick in at <= 100us, otherwise the mosfet might not survive.

 

[manojtm]

Max SOA for IRFP4227 is 30A at 70V(drain-source) for 100usec pulse duration.

5 ms is too long... protection should kick in at <= 100us, otherwise the mosfet might not survive.

Hi,Jlester,

OC protect sense should be below 100us so not a problem for MOSFET
i said DC protect sense is 10ms

Regards
MANOJ

 

[Deleted member 148505]

Sorry, I misinterpreted your post.
Guess I have to integrate the lm311+ne555 OCP protect in the pcb.

Thanks!

 

[manojtm]

Guess I have to integrate the lm311+ne555 OCP protect in the pcb.

Hi Jlester

your class d fsw=250KHz (Period is 4us) so you need 25us sense is max for OC(high current) detect for IRFP4227.so only ne555 is enough for OC sense(15us).Lm311+ne555 is better choice for high freq. operation

Regards
Manoj

 

[akraj]

Hi Manoj:

I managed to repaid both the boards, now the BIAS voltage is okay, it is +ve with reference to -Ve rail.

and Amp board has 6.2 volts at two side, output from 7806 is okay from -ve reference.

now the problem is the 47ohms resistors are burning out immediately when I power on, and I get some noise from main inductor (core from old PC psu).

and the relay of power board triggered one/two times but now it is not switching and connect spk connection.

There is 0.2mil volt at spk out, FETs are just warming.

Please suggest me what to check now and which position to stop 47ohms burn and make the amp workable.

Thanks in advance.

 

[aman khalsa]

FET's are ok or not did u chek them.?? and how about ir 2110 ???

 

[akraj]

I checked FER's, they are okay. How to check IR2110? Or 7404?

 

[IRSound]

How to check IR2110? Or 7404?

check output pulses with scope. or replace them with new one if you know the problem come from this components.

 

[akraj]

check output pulses with scope. or replace them with new one if you know the problem come from this components.

I replaced all the IC's couple of times but no luck. Need to check with scope but I don have that.

I can manage scope, I guess but what will be the idle data/output from ir or 7404 or op amps.

Now the output relay is not conducting. No dc/AC volt at output, guess this is usual but if I connect Spk directly, touching input pins of op-amps then it starts huge noise even after removing my finger! Around 14dc comes from Spk line. After off/on voltage is gone.

Where I'm making mistake?