MRF422 push pull HF linear. How much current need?
It can work from 20-28v.
How much current I should expect to draw at 28V?
Also how much at 24V?
If we assume that AB-Class PA has %60 PAE max. current will be around 250W/0.6*24=17A.
But efficiency will be less than mentioned value so current consumption can be considered more than this including other loss arguments.
It would be around 20-25A..
Thank you, when I bought this more than one decade ago, I think they have told me around 25A, but I needed to make sure.
I saw that the max consumption of the MRF422 is 6.7A so I was not sure why they have told me 25A for a push pull.
I have two 80AH SLA batteries which I can connect in series to get 24V, for 250W out on this instead of 300W. At 250W the IMD is lower and the harmonics produced lower.
So would you expect to draw 25A at 24V also?
If you connect 2 batteries in series, max. permissible current will be half of each battery. 24V@25A can be also be obtained a high quality transformer and power diodes with a proper parallel electrolytic capacitors.Because this amplifier doesn't need a precisely regulated power supply.Simply diodes+capacitor will be good enough.
Could you please tell me why it does not necessarily need a regulated PSU? I thought it is mandatory
It's not necessary because voltage ripples will not effect the performance of the amplifier if they are in acceptable limits.Furthermore, if you use AM or envelope modulation, ripples will have same frequency of modulation frequency that is considerably high.
That's why a simple diode+proper capacitor value power supply is good enough.
Thank you!
Does this immunity to ripples happen because of the push pull configuration, or is it irrelevant?
Yes, common mode currents will ideally cancel out each other and there won't be ( ideally ) any ripple coming from modulation effect.
But practically, some may occur..( minor phase errors between branches..)