Can anyone help,
I have been looking at the SOA graph and info for the irf9640 and irf960 and not quite sure how to inertpret the SOA data for the amplifier output stage. Using a worst case supply voltage of 100 volts as recomened by R. Slone ie (2*50volts) for inductvie loads, 100/8ohms = 12.5 amps peak for ech half cycle. divide by 2 for each transistor ouput stage half gives 12.5/2=6.25 so ech transistor has to handle 6.25 amps peak. Drawing a line acros horizontaly so that it intersect the 100 volt line show that it enters a region were the transistor can only withstand this current and voltage for 1ms. Have I interpreted it right. According to the graph VGS has to reduced to less than 20 volts for the transistor tro operate continously without damaging it. Is this correct.
Thanks
I have been looking at the SOA graph and info for the irf9640 and irf960 and not quite sure how to inertpret the SOA data for the amplifier output stage. Using a worst case supply voltage of 100 volts as recomened by R. Slone ie (2*50volts) for inductvie loads, 100/8ohms = 12.5 amps peak for ech half cycle. divide by 2 for each transistor ouput stage half gives 12.5/2=6.25 so ech transistor has to handle 6.25 amps peak. Drawing a line acros horizontaly so that it intersect the 100 volt line show that it enters a region were the transistor can only withstand this current and voltage for 1ms. Have I interpreted it right. According to the graph VGS has to reduced to less than 20 volts for the transistor tro operate continously without damaging it. Is this correct.
Thanks
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steevo said:
Whatever is the power amplifier you are building now, you can rely only on *continuous* dissipation data of output devices: repetitive pulse or, worse again, singular pulse are definitely unreliable and dangerous in audio application (indeed pulsed data they aren't thought for audio use).
Hi
Piercarlo
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