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USBPD devices can either act as the source (charger) or sink (device) or DRP (both). For our purposes we probably want a sink-only chip since we'll be plugging a charger into this board and the output will be a 12V/GND line. We don't need this to act as a source from a wall outlet.
Compatibility with USBPD 2.0 and USBPD 3.0 would be nice to allow us to use a wider array of laptop chargers.
USBPD 2.0 allows for fixed voltage outputs of 5, 9, 12, 15, and 20V
USBPD 3.0 allows for incremental voltage outputs anywhere from 3.3V to 21V in increments of 20mV. This is called PPS (programmable power supply). We don't really need this since we only need to provide fixed 12V and 5V.
Perhaps considerations should be made for USBPD 3.1 as well, as that would allow for a higher power delivery of 240W and possibly support driving contactors.
3.1 is backwards compatible so designing a 3.1 sink should allow for interfacing with 3.1/3.0/2.0 source
Since we want to max out current I think 3.1 makes the most sense as USBPD 3.1 EPR (Extended Power Rating) cables have the capability of providing up to 240W @ 48V
This may have to wait as there are not many 3.1 sink chips available
According to this reddit post, USBPD3.1 @ 240W probably isn't possible since the sink functionality of it is not well supported. I took a look at a few chips such as ST-ONEHP and TPS25730USB.
USBPD Controller Chip Evaluations:
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Buck Converter Research:
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Input Voltage Range
Buck Converter Pipeline
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See section 7.2.2 of the datasheet linked above.
We’ll be using the same buck for both 15/20 → 12 and 12 → 5 purposes. From https://github.com/lhr-solar/USBCPowerPCB/blob/v1.0/TPS56A37.xlsx, the appropriate component values are as follows. Note: calculations were done with Io = 10A since this buck is designed to carry that load. 15/20V → 12V UVLO: Vstart at 14.25V, Vstop at 12.75V
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Component | Value | |||||||||||
R1 | 73698.63014 | |||||||||||
R2 | 8367.029549 | |||||||||||
R6 | 73.2k | |||||||||||
R7 | 10k | |||||||||||
L1 | 3.3uH |
ORring Diodes:
ORring Diodes:
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5V → Isolated 5V converter:
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Part/Mouser Link | Purpose | Notes |
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Infineon CYPD3177-24LQXQT | PD Controller | |
TI TPS56A37RPAR | 12-20V to 12V buck converter | |
Phoenix Contact 1332645 | USB Type-C Connector | PD only requires a subset of the pins of USB Type-C, so a 16 contact connector is fine. (note: i believe we could have even gotten away with a 6 contact connector, but we need to support 5A and the 6p connectors on Mouser only support 3 :/) |
Infineon IRF9358TRPBF | Main Power P-Channel MOSFET | Same as used on evaluation kit |
Infineon BSL308PEH6327XTSA1 | Safe 5V Power P-Channel MOSFET | Same as used on evaluation kit |
Kingbright APTD2012LSURCK | Red Fault LED | Standard LHR Mouser Component |
onsemi NVTR4503NT1G | Fault LED N-Channel MOSFET | Same as used on evaluation kit |
Bourns SRP1265A-5R6M | 15/20V to 12V Buck Converter Inductor | See above (TPS56A37 Buck Converter Calculations) |
Bourns SRP1250-3R3M | 12V to 5V Buck Converter Inductor | See above (TPS56A37 Buck Converter Calculations) |
Nexperia BUK9K52-60RAX | 12V and 5V Outputs N-Channel MOSFET | For use with PG (power-good indicator) of 12V buck and 5V buck
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