SMU v3.1

[ducky64]

WORK IN PROGRESS. LAYOUT TO BE DONE. SOME PROTECTION CIRCUITS TO BE ADDED.

SMUv3.1 and associated infrastructural changes. Major improvements to reliability, stability, and (hopefully) resolution (noise floor). Resolves #351

Changes:

• Change emitter follower to be able to independently control gate on status on high and low sides
  • Refactor to use positive gate voltage instead of power
• Rename ErrorAmplifier -> GatedSummingAmplifier to better reflect the standard topology
  • Improved docs
  • Add optional fine target input
  • Add optional sense output, upstream of the gating / resistive output element (to detect current limiting mode)
    rails, for headroom on analog switches
  • Make gate clamping voltage (zener) a parameter
• Add JFET current clamp and simulation
• Refactor SMU control schematic:
  • for readability
  • to be self-contained
  • change current sense amplifier to use inamps
  • better output protection with a R-C snubber and low-leakage TVS diodes
• Add S-R inverted latch as SMU only block
• SMU top changes
  • Add 7-8A blowy fuse to the USB input
  • Use buck converter for direct Vbus -> 3.3v digital
  • Add INA219 power sense on Vbus input and Vconv in
  • Run Vcontrol- off analog rail, with ferrite filter
  • Add precharge
  • Add current limit trip sense direct to MCU
  • Use RC for OLED reset, because we're out of MCU pins
  • Add another IO expander for low-speed controls, because we're really out of MCU pins
  • Use SR with priority for converter OVP - should be more robust
  • Add I2S speaker
  • Simplify HDL using some new libraries
  • Add experimental block diagram grouping directive
• Rebaseline netlists

Libraries added:

• Add AnalogCapacitor as a cap to be sprinkled on analog lines. Apparently this is a thing in analog design.
• Add VoltageComparator, a comparator against a set (absolute) voltage.
• Add base SeriesPowerFuse, for blowy fuses
• Add SeriesResistor generator, that breaks a resistor into a series combination, to increase power and voltage ratings. Applies derating for worst-case tolerance stackup for individual voltage and power ratings.
• Add summing amplifier ratio calculator for n-ported noninverting summing amplifier, with unit test. No block yet.
• Add differential-RC filter
• Add FetPrecharge
• Add more KiCad symbols to analog signal chain parts: voltage dividers
• Add Nano2 / 154 series fuseholder, with no modeling.
• Add INA826 in-amp
• Add SN74LVC2G02 dual NOR gate
• Add TLP170AM low(er)-cost SSR

Libraries modified:

• Add mclkin for MCP3561, so we can overclock those ADCs
• Add addr lsb selection on INA219

Core changes:

• Add range-float subtraction (in addition to existing float-range subtraction).
• Add Ratio (like kOhm, and nFarad, but for unitless), which cleans up a lot of cases, resolves Ratio unit type #391
• Add as_voltage_source adapter for AnalogSource
• Add KiCad instantiation to SeriesPowerResistor

TODO:

• VoltageComparator : change to take in an analog signal, and do something with the voltage divider (perhaps a local analog -> voltage source block)
• SN74LVC2G02: change connectivity requirement to equals not implies
• Re-pinning
• Layout 🤪