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
• MCU needs:
  • A few analog channels
    • 4 12-bit ADC channels (voltage, current, heatsink temperature, UI pot)
    • 1 PWM or DAC channel (input into op amp)
  • A bunch of digital channels
    • 2 for a quadrature encoder for the UI
  • 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
        • CC/CV mode?
      • I2C
        • LTC2453 I2C 16-bit ADC for current and voltage measurement
    • Outputs
      • Digital
        • 1 for a CC/CV mode relay (if required)
    • Would need external ADCs in this case because built-in ones are only 10-bit
• An LCD would be cool to plot the response of load variations without a PC (transient response, current limits, etc.)
  • Could use a simple STN monochrome panel, would be cheap and work well
  • Could alternatively use a touchscreen OLED, would be expensive but look really cool
  • Middle ground would be a touchscreen LCD, which would be not-crazy-expensive and still look pretty cool
  • With any of these options, want the critical UI bits to be physical controls (current/voltage mode/setting)