50VDC RF power supply

[duck]

Hi,

I'm looking to build a 50VDC power supply to power a 300W Philips BLF278 RF amplifier.

I can't seem to find any circuits on the internet which provide the required 50V(ds) ~6A or more to run the thing. Does anyone have any ideas how I would go about modding an existing circuit, can I just change components to handle higher power in an existing 50VDC 3A circuit?

Better yet, will the High Current Power Supply in the projects section suit what I'm after, or will I need more precise filtering?

The BLF datasheet says the transistor can handle a max drain voltage of 125V, so would I get away with just using a 50V tordinal transformer without any smoothing/regulation?

Thanks

 

[ante1]

Hi duck,

Welcome to this forum.

What are the manufacturers (Philips) requirements for stability and filtering of the power supply? I seem a bit low (6A) at 50 volts if the power is 300W.

 

[duck]

What are the manufacturers (Philips) requirements for stability and filtering of the power supply? I seem a bit low (6A) at 50 volts if the power is 300W.

I probably agree with you. I have a friend who owns a commerical FM amplifier, though with a different MOSFET. He says at times up to 8 or 9 amps is drawn.

Class B operation for the BLF177 gives 70% efficency, about 19-20db gain.

LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT
VDS drain-source voltage - 110 V
VGS gate-source voltage - 1877.PDF

 

[ante1]

Hi duck,

It would be interesting to know which kind of PSU (stabilized or not) your friend is using. Anyway I wouldn

 

[duck]

No problem, I was only tossing ideas around.

The BLF177 is about $200 anyway, and for my first major electronics project I think I'll choose something a little cheaper and easier to power. I'll let you know if I have any more questions.

Thanks, very helpful!