Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]
<prev [Date] next>
[Advanced]
 <prev [Thread] next>

Re: LF: Re: Hall Effect for Over-current shutdown?

from [Warren Ziegler] [Permanent Link][Original]
To: rsgb_lf_group <[email protected]>
Subject: Re: LF: Re: Hall Effect for Over-current shutdown?
From: Warren Ziegler <[email protected]>
Date: Mon, 8 Apr 2013 15:07:09 -0400
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:content-type; bh=Yl9yZA2+w6bQNYcgbI3duoWFNbWAwPdraOhvES285UI=; b=PcqUbQOP8yEZwkd3B/F0AEf+H+HRJz5vIivvLgWKqzj+GWim6y9/J21o+8noBdMmTY qx/W6FyrNxB8p7eD4PY0o+MggX94uzn837oy33dhNrEYMyOhRy4PXs7qymdnJ7phiigw gLTz8t+jWGEDMuUbFFpz6n/nbGXl303S65bOt3j5o91PJ8kHpu2eG3qM8bogY4dMXu7u kYnxoE1VnjjnZBBaG9Icw+On4hwz/auO5T1UFrDgmaI75aHsRPu2GQDtUIFPvdV8kZfX giAv4g/tRbTR/B+xOc/vrERAcGpyI6eqvMFxvwA6/MsfowlAZ/N1CNVhScqIu2vZ83h6 7zyw==
In-reply-to: <DDBD5FEFA9D54CFBBA837A621F32FD94@gnat>
References: <CAMFjj73hzB0vnSNhtR-cAm0Tp8RZoVbT02yiW4xnV9+h1OftNg@mail.gmail.com> <DDBD5FEFA9D54CFBBA837A621F32FD94@gnat>
Reply-to: [email protected]
Sender: [email protected]
Hi Alan,

    I've modified the G0MRF amp with the M0BMU output configuration, I'm using a 30V supply.
The G0MRF uses a current sense resistor to shut down the amp quickly in case too much current is being draw.
I've modified the output transformer turns ratio to produce more power at lower supply voltages (I'm using 500V, 55a FETs).
However with the new higher currents and with a new appropriate value sense resistor its developing a LOT of heat (12 W or so) and needs to be heat-sinked.
I'm thinking Hall-effect might be more efficient and produce less heat - I'm pretty sure that others have used Hall effect devices to protect MOSFET amplifier and I'm looking for circuit tips.

73 & Tnx!
Warren




On Mon, Apr 8, 2013 at 2:52 PM, Alan Melia <[email protected]> wrote:
Ah interesting problem Warren.... why is it over-current?? if it is over-current because a high voltage has welded/melted a short between drain and source, then the protection wont help ....high currents usually lead to excess heating ......but what is the real cause? If you really need DC supply protection would not a high-side current monitor be easier/faster??? The problem then could be there is enough energy stored in the PA choke to zap the FET before, or even if, you can disconnect the supply.
 
OK drive fails permanently on might be a condition it would protect the FETs against with DC coupled drive
 
Alan G3NYK
----- Original Message -----
Sent: Monday, April 08, 2013 7:15 PM
Subject: LF: Hall Effect for Over-current shutdown?

Anyone using a Hall effect device for overcurrent sensing and shutdown in a MOSFET amplifer?

--
73 Warren K2ORS
                WD2XGJ
                WD2XSH/23
                WE2XEB/2
                WE2XGR/1

 



--
73 Warren K2ORS
                WD2XGJ
                WD2XSH/23
                WE2XEB/2
                WE2XGR/1

 
[More with this subject...]
<Prev in Thread] Current Thread [Next in Thread>
Previous by Date:  LF: Hall Effect for Over-current shutdown?, Warren Ziegler
Next by Date:  LF: Re: Hall Effect for Over-current shutdown?, Alan Melia
Previous by Thread:  LF: Re: Hall Effect for Over-current shutdown?, Alan Melia
Next by Thread:  RE: LF: Re: Hall Effect for Over-current shutdown?, Clemens Paul
Indexes:  [Date] [Thread] [Top] [All Lists]