Class D Audio Amplifiers

[Cristi]

In horizontal position, the IRS2092 amplifier module is 38mm tall, and the 400W-600W versions has one taller capacitor which brings the maximum height to 42mm.

[CharlieLaub]

Hi Cristi,

I have a question about your IRS2092 Modular Amplifier (the mono amp module). Assuming I have a 500W transformer with 50-0-50 secondaries, possibly as high as 54-0-54, can the IRS2092 Modular Amplifier be used with that? Assuming a full bridge type rectifier and 1.4V drop through the diodes, this would give me +/-68V to +/-75V rails, which is just in between the 400W and 600W versions of the amp.

Can this transformed be used with either the 400W or 600W version somehow?

How about the TA0105ARB board with this transformer? Perhaps that would be a better choice?

-Charlie

[Cristi]

Hi Charlie,
the obtainable voltage range is just above the supply voltage range of the 400W module and under the supply voltage range of the 600W module. but, is still possible to configure the 600W module to work with this voltage. the main difference between the modules are the output devices, gate drive resistors, dead time setting and overcurrent threshold. then the under-voltage and over-voltage threshold which is determined by the values of the zenner diodes used. lastly the bias supply resistors. there are about 10-12 components which have different values/type from the 150W to 400W or 600W version.
in conclusion is possible to set a module to work with the voltage which you have but must be configured so.
TA0105ARB low impedance version can work with the available voltages.

[CharlieLaub]

Originally Posted by Cristi

Hi Charlie,
the obtainable voltage range is just above the supply voltage range of the 400W module and under the supply voltage range of the 600W module. but, is still possible to configure the 600W module to work with this voltage. the main difference between the modules are the output devices, gate drive resistors, dead time setting and overcurrent threshold. then the under-voltage and over-voltage threshold which is determined by the values of the zenner diodes used. lastly the bias supply resistors. there are about 10-12 components which have different values/type from the 150W to 400W or 600W version.
in conclusion is possible to set a module to work with the voltage which you have but must be configured so.
TA0105ARB low impedance version can work with the available voltages.

Hi Cristi,

Thanks for the reply! I think that the 600W IRS2092 Modular Amplifier, built up for these rails, would be the best approach. The detuned 600W module is a good match for the transformer rating, too.

How do I order the customized amp module? I assume that I need to tell you the rail voltage (or range or rail voltages) that I would like to use... what is the best way to give you this information?

-Charlie

[Cristi]

Charlie, please send me a mail when you need the boards and you can remind me what configuration you need. basically you can order one or more 600W module(s) for which i need to modify the UVP level, to accommodate lower voltages, as well as bias and OC resistors.

[petegt]

Hi Cristi,

Im not sure if you recieved my email :/

I have a similar set up as charlie is suggesting

54-0-54v transformer, bridge rectifier, 80v 15000uF capacitor per rail. However I have measure the dc rail voltages that this outputs with no load as +/- 86.3V.

Would the 600w module be safe on these voltages or would I have to unwind the transformer to get the voltage down to roughly 80V?

Pete

[Cristi]

Hi Pete,

your transformer will roughly give +-76V DC at idle and up to +-80V considering the mains voltage variations. the lower limit depends on the transformer size and load, and can go down to +-60V in worst case. thus a 600W module can be used if the under-voltage threshold is set to about 60V and the bias resistors as well. no need to unwind the transformer unless you want to use a lower power module such as the 400W or 250W one(s). what is the size and power rating of the transformer ?

[petegt]

This is the PA amp I have, was in the process of repairing but the pcb's on the output stages are in very poor condition.


The power rating of the transformer is not written on it but the amplifier its from was class AB producing 400Wrms 4ohms and 240Wrms 8ohms per Chanel.

Separate transformer etc for each Chanel. Each transformer weighs about 8kg

Each 54V output before rectification has a 10 amp fast blow fuse.

My mains voltage is 244-247V so this probably explains the high rail voltage.



Im glad to know I could use the 600w module with a couple of components changed

Do you think I could maybe use 2 per transformer?

[petegt]

Would I be right in calculating these transformers are roughly 1000VA?

[thesoundkid]

well if it's 400wrms into 4ohms and its class-ab

I'd guess they are about double the output power ideally so 800va each at the most i would guess, because I doubt they would overrate it.