Wanted to add this here to keep a record of what be have talked about for power distribution schematic before everything on slack disappears.
REGULATOR SECTION:
In the regulator section, the PB2_5V_EN signal will be at V_BAT when R8 is populated. I don't think this is too good for the controller board.
For the PB_5V_Monitor signal, we're not too worried about power consumption, but if we wanted to reduce parasitic current draw, we could swap the bottom resistor for a 3V Zener and increase the value of the top resistor to 100K or something like that.
Why use 100V ceramic caps for the 5V output? Switch to the 50V 0603s that you are using elsewhere on the board unless there is a reason that I am missing.
On the subject of cap voltage ratings, could you choose a C7 with at least 10V. I'm not sure if you're aware but ceramic capacitors can decrease capacitance by up to 50% when the applied voltage reaches the voltage limit.
On the subject of caps, are C7 and C9 different packages? Why? And I think that is over the recommended capacitance, see Table 2 in the datasheet. Probably split it into 2x 22uF ceramic capacitors with 10V+ rating.
Does the inductor have the correct current ratings? Also, it is out of stock so I replaced it with these (MPLCH0740L3R3) on the order for the center console boards.
What is the purpose of R3?
CONNECTORS:
See my earlier comment about switching the power inputs (P3) to a barrier block with screw terminals.
I don't think it makes sense to have a 6-pin connector on the DRLs. These will be split to the 2 sides of the car, so it would be better to have an 8-pin so that 2 wires can go to pwr and 2 wires can go to GND on each side.
Please change all the Pi power connectors to Micro Fit (instead of ultrafit per discussion last Saturday).
Also, general comment here - why so many paralleling wires? I think the Micro Fit connectors have plenty of current rating. Was this for redundancy?
OUTPUTS:
Driver Display takes 19V in. We need to add another DC-DC converter to power it. Contingent on testing for the current requirement.
Make sure that the part numbers for the single output load switches are in the schematic (U4, U18, U19, etc)
And go over all the outputs to ensure they can be renamed for the rear power distribution
MUXES:
What is the part number of U12? Could you make sure this is in the schematic?
It would be good to add a text label to show what the muxes are for: "Load switch enable io expanders" and "Current Sense Muxes"
Bypass capacitors on these? Are they on another sheet and I'm just not seeing them?
For U12, the current sense input mux, it does not handle input voltage above the supply voltage. There are 5.1V zeners on the signals that feed in to these, but those are useless as the chip may not function properly (outside recommended operating conditions Section 6.3 in datasheet). I think a 2A load will give us about 3.6V (but double check my math) which would not be good for the MUX. Might be a good idea to switch these zeners to 3V3, and maybe double check the expected loads and measurement range for the higher power outputs - we could also increase the accuracy of the lower current outputs by changing the 1.21k resistor as well.
If there are smaller packages for the large load selection muxes, it would save a fair bit of space to switch.
OTHER:
Add 2 external GPIOs with pull-up resistors for the parking brake limit switches. We might be able to accomplish the torque limiting through the current measurement, but good to have a mechanical backup.
Decoupling capacitor on U5
Input Connector - a barrier block will remove the need to crimp around 28 micro-fit crimps. I think we should switch to the barrier block design.
Is R2 for current sense on the 5V output? - we already get current from the load switches.
Boost converter - why 100V capacitors? Switch to 0603 package. Does the layout guide mention anything about putting smaller capacitors closer in the chip or anything like that?
The horn only needs a 2-pin output connector. We'll use the 18AWG microfit crimps, rated for 8.5A. The horn we are planning to use only uses 4.5A. CORRECTION - it draws 7.7A, but not consistent due to the working principle of the horn.
What is the rear pi used for? - was this the pi that might have been connected to the display? (Battery Pi is connected directly to BMS Carrier)
Current limiting resistors for the LEDs on the 5V outputs should be changed to give the same current as the 12V outputs.
Why is C26 an 0805 part? - make it 0603. And fix that voltage divider to either a 100K and zener, or equal value resistors.
DRLs are going to draw 2A max, we don't need 6 wires for them. We only want 4 wires, as the left and right DRLs will go to different drivers. (This might be a good idea to keep as 6 though since if we want to use for the rear brake lights as well, there are 3 of those.
Turn signals only need 2 wires each (not 4).
Add extra mounting points to the middle of the board - we will be pushing and pulling the connectors, and don't want the board to bend. I would put one each in the following locactions: Between P10, P11 just above the connectors. Between P5, P6. Between P20 and D5. Between P3 and the inductor
Move the internal traces on the signal layer away from the controller board mounting holes, and if possible switch the controller board mounting to the standoffs that Aashmika is using on solar.
Make sure the all connectors and pinouts get labeled.
What are all the Vias for near the input connector?
Dedicated outputs for monitor, parking brake
Parking brake output should be changed to an H-bridge driver to be able to move current both ways through the parking brake for forward and reverse current. More discussions around parking brake safety and accidental actuation should be covered before fully settling on an electric parking brake.