[WIP] Power Board Component Selection

[WIP] Power Board Redesign Considerations

IC & Controller Selection:

List of Components:

Component Selection (LTC4421):

Datasheet: LTC4421 (Rev. 0) (analog.com)

1. Current Limit Regulation and Setting Current Limit

2.  

3. Output capacitance Cout:

   1. LTC4421 “break-before-make” (fully disconnect first channel before connecting second channel to avoid cross-conduction, accidentally charge the other channel)

      1. Results in some dead time during switchover/ voltage droop

      2. ESR voltage step at the capacitor due to equivalent series resistance: Simple Explanation of Capacitor ESR | DigiKey

   2. Output voltage droop as load current discharges Cout → Cout provides discharging rate of load current/ Cout until second channel switches in

   3. Cap Selection: 1) correct value, and 2) low ESR to reduce Vstep

4. Output voltage charging time:

   1. Overcurrent fault timer runs during charging, tTMR,FLT > tCHG,MAX

5. N-channel MOSFETs (conduct current to output):

   1. MOSFETs’ voltage > LTC4421 14V max gate output

   2. MUST be able to handle short circuit longer than tTMR,FLT → while shorting, current is regulated by current limiting circuit/ overcurrent fault timer

   3.