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Class D Audio Amplifier IC Forum Discussions

Monforte
Level 1
First reply posted First question asked Welcome!
Level 1

I am looking for an audio power amplifier that can operate at very high voltages. It appears that an IRS2452 can drive a high voltage FET, given enough transconductance. I can get FETs that operate up to 1KV.

This amp would not be driving a loudspeaker. Instead the load is a capacitance in the range of 500pF. It must swing as high a voltage as possible, but the power would be almost negligible.

I am not sure if this or another amp chip might be the best choice. Also, I have been looking for a development board to experiment with. There seems to be no stock in this range of products.

Any suggestions would be appreciated.

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1 Solution
Meghana
Moderator
Moderator 50 solutions authored 5 likes given 100 replies posted
Moderator

Hello Monforte,

As you may already know, transformer has to be connected after the filter circuit and not directly on the midpoint of the switching leg. There is an evaluation board available for IRS2452, i.e., IRAUDAMP23. Currently it is out of stock. You may try to place a back order on digikey to check if the lead time is acceptable for you. 

https://www.infineon.com/cms/en/product/evaluation-boards/iraudamp23/#!documents

https://www.digikey.in/en/products/detail/IRAUDAMP23/448-IRAUDAMP23-ND/11311989?utm_campaign=buynow&...

 

Please be noted that this device is only capable of providing a swing of maximum 400V in both +ve and -ve direction when connected in BTL mode.

Also can you please let us know more details about the application for which you are evaluating this solution. We may be able to provide better solution if we have these details. 

Regards

Meghana R

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Meghana
Moderator
Moderator 50 solutions authored 5 likes given 100 replies posted
Moderator

Hello Monforte,

IRS2452 has maximum bus voltage rating of 400V. Unfortunately, we do not have class D solutions which can support bus voltages near to 1kV. Can you please let us know below details, so that we can suggest you an appropriate solution.

1. Input type-- Is it an Audio signal or some standard control signal?

2. If its a standard control signal, what are the input characteristics - Voltage range, frequency

3. Maximum output voltage required.

Regards

Meghana R

Monforte
Level 1
First reply posted First question asked Welcome!
Level 1

Hello Meghana,

Thanks for your response.

The source is a normal audio signal. 400v works for me. A bridged pair will get me to twice that. I may have underestimated the load. It might be as large as 5000pF but still a pure capacitance.

Is the IRS2452 a good choice here? Is there a development board available?

 

Best,

John

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Meghana
Moderator
Moderator 50 solutions authored 5 likes given 100 replies posted
Moderator

Hello Monforte,

Voltage can swing in both +ve & -ve side with bridged pair but limited to max value of 400V in each direction. But there are also other concerns in regards to your application. Are you intending to use this pure capacitive load after the filter or directly on the midpoint of the switching leg? 

If its latter, then this could result in damage of the switches, as during positive cycle, the current through switches is only controlled by on-state resistance of the MOSFET which would be in mohm range. Hence the currents could be really high which the MOSFETs cannot withstand. 

Even though the IC has the overcurrent protection feature, it will not be fast enough to detect these short circuit currents. 

If we are understanding your application differently, could you please share a draft schematic of it. So that we can analyze it and suggest you the right product. 

Regards

Meghana R

Monforte
Level 1
First reply posted First question asked Welcome!
Level 1

Hello Meghana,

Thanks again for your response.

I have attached a sketch of the sort of setup I am looking at. I need to see what sort of inductances & reflected capacitances are represented by the transformer to factor into the filter design parameters.

Is the IRS2452 a good choice here? Is there a development board available? I can't find stock anywhere.

 

Best,

John

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Meghana
Moderator
Moderator 50 solutions authored 5 likes given 100 replies posted
Moderator

Hello Monforte,

As you may already know, transformer has to be connected after the filter circuit and not directly on the midpoint of the switching leg. There is an evaluation board available for IRS2452, i.e., IRAUDAMP23. Currently it is out of stock. You may try to place a back order on digikey to check if the lead time is acceptable for you. 

https://www.infineon.com/cms/en/product/evaluation-boards/iraudamp23/#!documents

https://www.digikey.in/en/products/detail/IRAUDAMP23/448-IRAUDAMP23-ND/11311989?utm_campaign=buynow&...

 

Please be noted that this device is only capable of providing a swing of maximum 400V in both +ve and -ve direction when connected in BTL mode.

Also can you please let us know more details about the application for which you are evaluating this solution. We may be able to provide better solution if we have these details. 

Regards

Meghana R