Anchor

Anchor will be an electronic current/voltage sink, for testing/characterizing power supplies and other similar tasks.

• Desired features/specs:
  • Constant current and constant voltage options
    • Maybe constant power too?
  • Ramp-up/down automatically and track outputs
  • Pulse load to test transient response
  • 5A/100V maximums
    • 500W dissipation in a FET is a bit nuts, so it won't be 5A *at* 100V
    • 100W continuous, 500W pulse might be reasonable? Would be nice anyway.
  • Some kind of computer interface for more complicated tests/more detailed data analysis
    • USB would be easy to implement
    • Ethernet could be cool, but that seems overkill here
    • GPIB would be the traditional choice for test gear, but I've never done any work with it
  • Temperature monitoring (a couple channels worth) would be good, as you often want to monitor chips/pass elements/etc. while load testing supplies
• PIC24FJ256DA210 will be used as it has all the graphics/LCD drive/acceleration built in to enable a nice colour TFT display
  • Inputs
    • Digital
      • Load On/Off
      • Event trigger switch
      • CC/CV mode?
      • 2 for UI quadrature encoder
      • 2 for touchscreen
    • MCU-integrated 10-bit ADC
      • Heatsink temperature
      • UI pot (if used)
      • 2 for touchscreen
    • I²C
      • LTC2453 I2C 16-bit ADC for current and voltage measurement
      • AR1020 I2C resistive touchscreen controller (will try to eliminate it and do it in the PIC for revision 2)
  • Outputs
    • Digital
      • CC/CV mode relay (if required)
      • Scope trigger output
    • Analog/PWM
      • Output drive (to op-amp)
• Want a graphical LCD for the output/UI, and the PIC chosen will drive a nice TFT
  • WQVGA is a nice size, can get a menu/buttons on the side and still have room for the info display
  • Likely still want the critical UI bits to be physical controls (current/voltage mode/setting)
  • The Newhaven NHD-43-480272MF-ATXI-T-1 from Mouser seems the best option for size/touch/resolution