Motor Controller Interface Board
Status | Requirements Review |
Owner | @Jennifer Li |
|---|---|
Approver | @Ravi Shah @Jacob Guidry |
Due date | Feb 27, 2026 |
GitHub | Provides power conversion/protection and fan control for the Prohelion WaveSculptor 22 motor controller - lhr-solar/PS-MotorControllerInterfacePCB  GitHub |
BOM |
|
Due Dates:
Schematic - 9/27/25
Layout - 10/4/25
Rev. A Ordered - 10/13/25
Firmware/Testing - 11/1/25
Rev. B validation - 2/27/26
Description/Purpose
This board allows the car’s electrical system to interface with our motor controller, the Prohelion WaveSculptor 22. It handles power conversion and fan control to ensure the motor controller stays within appropriate temperature bounds.
Requirements
The WaveSculptor 22 requires a voltage between 9v and 15v on its low-voltage connection. Since our vehicle LV system is 24v, this board must step that down to 12v
Interface with both 2 and 3 wire fans to keep the motor controller cool
Read temperature data over CAN from the motor controller to run fan control loop
Uses the PeripheralSOM for MCU, power, and CAN circuitry
Must fit in the motor controller enclosure
RevB Testing Plans:
HARDWARE
Use multimeter to check for shorts ✅
Check for any physical damages ✅
Solder connectors and fuse ✅
PSOM
Get a lead to verify PSOM connector ✅
3.3V testpoint at 3.3V? ✅
3.3V status LED working? ✅
HSS circuit (datasheet: https://www.ti.com/lit/ds/symlink/tps27sa08-q1.pdf?ts=1767649538999)
Check HSS 24V output testpoint ✅
Test LATCH
Test HSS_EN ✅
Status LED working? ✅
Buck converter (datasheet: https://www.ti.com/lit/ds/symlink/lmr33630.pdf)
power the board (applying 24V), measure test point to ensure 12V output ✅
write code and test for buck converter output (12V_SENSE)
test BUCK_PG
PWM fans
Apply HIGH to mosfet gate using PSOM and measure fan connector terminals ✅
Flash PWM test to PSOM and test on phyiscal moco fans ✅
Edit PWM task using powertrain fan specs
Write a test and driver for fans TACH
Validate TACH code
PP
Overvoltage - Apply 12V directly to PP circuit and crank power supply up until the PP_OUT indicator LED goes out (should stop at 14.41V)
Test PP_OUT should be 12V ✅
Status LEDs
Test the LED driver using led_test (HB, SW_OC, HSS_FAULT, HSS_EN, OTEMP, FAULT, LED1 and LED2 hardware functionality good?) ✅
Misc
Find functionalities for LED1 and LED2, label them on PCBs
FIRMWARE
Low-level drivers ✅
CAN send
Confirmed software not hardware issue. Comparing with Surabhi’s code to find differences and get send working
CAN receive
High-level drivers
RevB Testing:
Pre PSOM
HSS output: 23.94V at 24V testpoint
Buck output: 12.14V at BUCK_OUT testpoint
PP output: 12.14V at PP_OUT testpoint
Post PSOM
3.214V at 3.3V testpoint
All hardware LEDs light as intended.
PSOM gpios:
In bootloader, FAULT (PB14) and LED1 (PB0) are the only gpios alive
OTEMP, HB, SWOC, 12V_SNS, LED2, HSS_EN, HSS_FAULT, BUCK_PG are dark
Possible psom connector issue? No. they’re probably just pulled high internally, just ignore it
When code is being executed, only PB0 is flashing (this is right and consistent with the old flashed code)
Flash code and run led_test, led_test works!
Run pwm_test:
no work, now shorting between GND and PSOM_PWR, probably shorted HSS chip
Back again
short was not on board, but rather on PSOM between 3.3V and GND (MCU fried)
Switched to PSOM 6 and cleaned up SOM connector (thank u mr shah)
pwm_test works, crimped connectors for better fan testing setup
Application Note
Context
Location of the board: Near the motor controller
Connection List
# | Name | Type | Part Number |
|---|---|---|---|
J1 |
|
|
|
Main
Schematics
Circuit Components
Layout
PCB:
3D Model
Firmware
Drivers
High-Level (Block Diagram)
RevA Testing
Validation progress:
24V-12V Buck converter: works, 12.18V output
24V Protection circuitry:
Overvoltage: 27.9V
Rpp: No because of TVS diode short
12V Protection circuitry:
Overvoltage: NA
Rpp: NA
Continuity: Yes across nmos when powered
Future plans:
RevB: Replace buck ic per changxu recomendation, max voltage is not high enough (get this man a true)