2020-03-25 Changes to Power Selection Board
- Micah Black
- Josh Rong
Owned by Micah Black
We should have calculations, sound reasoning, and documentation for all the values chosen for the following changes.
Inputs
Find Lower Resistance Fuse (Voltage Drops in Power Path Selection)
Ideally with a smaller package size as well (the fuse could be old therefore having higher resistance?)
MINI 297 (ATM)
Fuse Holder: Keystone Electronics 3568 - Digikey Link
Fuses: LittleFuse Mini 297, or Cooper Bussmann ATM - Digikey Link
MICRO (ATR)
Fuse Holder: I can’t seem to find any dedicated ones, but the Keystone contacts for the Mini series (without the cover) should work but is not as elegant.
Fuses: LittleFuse Micro2 327 or Cooper Bussmann ATR - Digikey Link
Ideally with a smaller package size as well (the fuse could be old therefore having higher resistance?)
MINI 297 (ATM)
Fuse Holder: Keystone Electronics 3568 - Digikey Link
Fuses: LittleFuse Mini 297, or Cooper Bussmann ATM - Digikey Link
MICRO (ATR)
Fuse Holder: I can’t seem to find any dedicated ones, but the Keystone contacts for the Mini series (without the cover) should work but is not as elegant.
Fuses: LittleFuse Micro2 327 or Cooper Bussmann ATR - Digikey Link
Use only 2 parallel FETs for the power selection inputs (Power Path FETs Power Dissipation and Temp Rise)
Find connector to replace screw terminal for easier assembly (not high priority)
TE ET Power, recommended per the Stanford Connector Selection document. We should stick with the Barrier Blocks or go with these I think:
Part numbers are on Pg 102 of this PDF: https://www.ttiinc.com/content/dam/ttiinc/manufacturers/te-connectivity/PDF/sg_tyco_ENG_CS_1773096_FULL_POWER_CATALOG_0512.pdf
Housing: https://octopart.com/1982299-1-te+connectivity-44516067?r=pap
Connector: https://octopart.com/2042274-1-te+connectivity-44516073
Crimps: https://www.digikey.ca/product-detail/en/te-connectivity-amp-connectors/927829-5/A122186CT-ND/5418209
TE ET Power, recommended per the Stanford Connector Selection document. We should stick with the Barrier Blocks or go with these I think:
Part numbers are on Pg 102 of this PDF: https://www.ttiinc.com/content/dam/ttiinc/manufacturers/te-connectivity/PDF/sg_tyco_ENG_CS_1773096_FULL_POWER_CATALOG_0512.pdf
Housing: https://octopart.com/1982299-1-te+connectivity-44516067?r=pap
Connector: https://octopart.com/2042274-1-te+connectivity-44516073
Crimps: https://www.digikey.ca/product-detail/en/te-connectivity-amp-connectors/927829-5/A122186CT-ND/5418209
Add current sense to power supply input (instead of 0 ohm resistor)
Unless there was a good reason it was not there to start
Unless there was a good reason it was not there to start
Aux Switch Implementation (to completely turn off the car)
Reset Loop
Power Distribution Testing for Switchover and Loops
Refine Capacitor values for lowering the inrush current
Reduce Gate Slew rate for DC-DC and Power Supply
Verify DC-DC voltage limits for UV (keeping in mind inrush current and voltage drop while running at 17A)
Check the AUX under-voltage time extension capacitor
Fix voltage sense locations (so that it is not affected by inrush current from capacitor to capacitor)
Temperature Sensing
Update temperature sense RC filter values
Check with Aashmika to get the DC-DC temperature sense pinout correct
Change 3V0 LDO to a non-QFN package
Separate the AUX power and thermistor connectors
So we can do a higher current connector for power and a small footprint connector for sense
So we can do a higher current connector for power and a small footprint connector for sense
General
Add fuse to output for output cable protection
Add block diagram
Consider making all current sense resistors the same
Consider adding input for the Charger 12V 5.5A output - so that we power the car from the wall when charging.