What is 300 Watt limit of Class D Audio Amp IRFB4020PBF ?

[GrCa_1363456]

With respect to Infineon's Class D Audio Amp, P/N IRFB4020PBF, the datasheet states, "Can deliver up to 300W per channel into 8 (ohm) load in half-bridge configuration".

What is this 300 Watt limit based on?

What are the test conditions?

Assuming the thermal design is okay, can it allow for more power and current than limited by this statement?

Reference datasheet linked @ https://www.infineon.com/cms/en/product/power/mosfet/n-channel/irfb4020/

Greg

[Nishanth · Accepted solution]

Hello @GrCa_1363456 ,

Thank you for contributing to the Infineon community.

It can deliver 300W while operating at a self-oscillating PWM of 400kHz with continuous rated power for 1 minute and having an 8 degC/W heatsink.

There is room to use it for a higher power. Since the rated power is not continuous in audio applications, it is highly dependent on test conditions. for example, if a larger heatsink is attached, the device will be able to deliver higher power.

Regards,

Nishanth

[喜马拉雅之雪]

Hi GrCa：

300W， it is basic on VDS.

For 300W/8R, the Vrms=49V. 

LPF voltage down is about: 22uH*2*3.14*1kHz*Vrms/8R=0.85V

The Vpk=50*1.414=70.7V

If PWMmax=0.9， need DC bus=>78.6V

Half bridge will work on +-80V for 300W output, it is top of the better work for 200V MOSFET.