Saturday, July 23, 2011

Solid State Amplifier Controller or Transistor Control Board

Freescale has released a new VHF/UHF transistors that has excellent ruggedness, reasonable matching, and high power output, the MRFE6VP61. Every amplifier needs a control board, so this is my attempt.

This controller design consists of a PCB with he following major blocks
  • 20 x 4 character LCD status and metering display
  • Analog meter drive
  • Drain Voltage solid state power switch
  • Drain current measurement
  • Forward and reverse power measurement
  • Relay sequencing for 28V input, output, and tower mounted coax relays
  • 28V to 5V power supply
  • Arduino Uno microcontroller socket
The initial design implements the controller in a box with the following features
  • On/Off switch which functions as fault reset
  • 20x4 character metering and status display
  • Analog meter for RF Power Out
  • 50V 50 Amp Input and output connectors using 75 Amp Powerpoles
  • EMI Filtered AC input
  • 28V power supply for Relays and SSAC
  • External Key input, ground to enable
  • External relay connector for Input, Output, and Tower Mounted Relays
  • Current limited switched 28V relay outputs
The Arduino Uno processor has a very easy to use programming interface that support good I/O, display, and fast response to events. The code resides on my SSAC_Arduino public svn.

The schematic and layout files reside on SSAC_Eagle svn repository.

The parts datasheet files, amplifier design documents, etc. reside on the SSA_Controller svn repository.

I wish these could all reside in one place, but apparently not. SVN doesn't use links, probably for good reason. Maybe, I can get Arduino and Eagle to use them...we'll see.

The SSA Controller implements a "shield" in Arduino terms that mates to the Ardiuno. The SSAC mounts to the metal enclosure to dump a few watts of heat and the Arduino mates to that.