Adom Custom Electronic Load - design/calcs.json

Overview Files Skills Packages Releases Dependencies Issues Breadcrumbs Pull Requests Activity

main

John Lauer R0 engineering checkpoint: checked schematic, sourcing, servo evidence and safety-policy code; PCB and qualification incomplete 10054d3 1h ago

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

{
  "status": "preliminary calculations; hardware unverified",
  "envelope": {
    "max_V": 24,
    "max_A": 3,
    "max_W": 25,
    "I_at_max_V_A": 1.0416666666666667
  },
  "shunt": {
    "ohm": 0.02,
    "V_at_max_A": 0.06,
    "W_at_max_A": 0.18,
    "INA226_fullscale_V": 0.08192,
    "range_margin_V": 0.02192000000000001
  },
  "dac": {
    "bits": 12,
    "reference_V": 2.5,
    "divider_top_ohm": 38600,
    "divider_bottom_ohm": 1000,
    "full_scale_A": 3.1565656565656566,
    "LSB_A": 0.0007706459122474747,
    "note": "0.1% selected divider; DAC gain/reference, resistor tracking and shunt tolerance still require a complete error budget. Full-scale formula denotes ideal span; maximum code is 4095/4096 of span."
  },
  "offset_error": {
    "OPA189_25C_max_A": 0.00015000000000000001,
    "INA226_max_A": 0.0005,
    "note": "Offset only; not complete error budget"
  },
  "thermal": {
    "ambient_C": 40,
    "case_limit_C": 75,
    "interface_assumed_C_W": 0.5,
    "thetaJC_max_C_W": 0.42,
    "allowable_sink_C_W": 0.8999999999999999,
    "junction_C_at_case_limit": 85.5,
    "note": "Worst-case all load power placed in MOSFET; interface is an assumption, must verify actual insulator and spreading. Fan free-air CFM is not installed airflow."
  },
  "initial_DUT": {
    "V": 5,
    "A": 1,
    "W": 5
  },
  "open_items": [
    "Selected sink with local TO-220 heat spreading",
    "Actual contact current ratings",
    "Loop stability with vendor transistor model",
    "Temperature sensor lag and trip margin",
    "Complete error budget and calibration",
    "Independent power and reverse polarity protection"
  ]
}