Created Fri, 19 Aug 2011 13:30:07 +0000 by wa1hco
Fri, 19 Aug 2011 13:30:07 +0000
The SSA Controller is a slightly oversize shield that controls up to 1500W RF power amplifier. Big amplifiers needs to shut down on over-current, excess reflected power, and need to sequence RF relays to avoid damage. The SSAC includes a 50V 50A FET switch, 50A current to voltage converter, Forward and Reflected RF power sampling, RF relay drive, transient protection, etc.
The control software manages relay timing and watching for proper operation. When commanded to transmit, the relays activate in sequence and lastly the 50V power bus turns on.
The software also drives a 20 x 4 LCD display showing status, voltages, currents, and RF power. A PWM output drives an analog meter because you just have to have one of those.
The high current makes for heating in the circuit traces, so the whole shield board mounts to a metal plate through a Sil-Pad.
Fri, 19 Aug 2011 17:38:47 +0000
Where'd you see it?