F1Tenth power board

This repository contains the power board design for a F1Tenth car.

Designed on Kicad 9.0.6.

History

This project was originally launched in the summer of 2024 at CTU, thanks to David Zahrádka, to facilitate easier experimentation for researchers.

Assembled PCB

Features

This board is designed to power all F1tenth components. Two 3S Li-Po batteries power the board. Those batteries are connected in parallel throught an ORing circuitry. This allow to hot swap batteries. The output of the ORing is named BATT_SYS and is directly connected to VESC output without protections.

The Jetson terminals is also connected to BATT_SYS but protected by a dedicated 5A e-fuse. The P_0 and P_1 terminals are connected to BATT_SYS through another e-fuse and can draw up to 5A.

A 5V 6A buck converter provide power to the USB A connector. This output is protected for overcurrent up to 6A.

SAFETY WARNING

Li-Po can provide huge amount of current. Be careful when handling the board. Do not short circuit the batteries and VESC output as they are not protected. Do not exceed the maximum input voltage: 20V.

PCB can be hot when drawing high current.

Absolute maximum ratings

	Min	Max	Unit
Battery voltage	6	20	V
Jetson current		5	A
P0 + P1 current		5	A
USB current		6	A
VESC current		60	A

File structure

• power_board.pro - Kicad project file
• power_board.sch - Schematic
• power_board.kicad_pcb - PCB layout
• symbol/ - Custom symbols
• power_board.pretty/ - Custom footprints

DRC

Design rules checks comply with JLCPCB capabilities.

Circuit

Ideal diode

Ideal diode behavior is achieved by LM74700 and the high power N channel MOSFET IAUCN04S7L005.

The J3 can be used to connect a battery life indicator.

Circuit for battery B is identical.

Buck converter

Provide 5V 6A to the USB connector. Data p and n are tied together as the USB connector is only used for power, it helps to trigger high current mode on some device.

TPS51386 also provide overcurrent protection, under and overvoltage protection.

E-fuse

Those e-fuse are used to protect the Jetson and the peripherals. The TPS25980 is configured to limit the current to 5A. It allow overcurrrent for 2ms to allow inrush current. Number of retry is unlimited and rise time is 1ms.

Terminals

Terminal are bornier-2_P5.08mm. They are used to connect the peripherals and the Jetson. They are from the MSTB series from Phoenix Contact. They can be easily unpluged and pluged.

PCB

BOM

Designator	Footprint	Quantity	Value
C1, C14, C15, C18, C2, C5, C6, C7, C8	0805	9	22u
C10	0805	1	22p
C11	0805	1	NC
C12, C13, C16, C21, C3, C4	0805	6	100n
C17, C19, C20, C22, C23, C24	0805	6	10n
C9	0805	1	1u
D1	SOT96P237X111-3N	1	3.3v
D2, D3, D4, D5	0805	4	LED
J1	USB_A_Molex_67643_Horizontal	1	USB_A
J7	TerminalBlock_bornier-2_P5.08mm	1	P0
J8	TerminalBlock_bornier-2_P5.08mm	1	P1
J9	TerminalBlock_bornier-2_P5.08mm	1	JETSON
L1	SRP12701R5M	1	1u5
Q1, Q2	IAUCN04S7L005	2	IAUCN04S7L005
R1, R13, R2, R4, R8	0805	5	150k
R10, R11, R5, R6	0805	4	1k
R12, R7	0805	2	620k
R14, R9	0805	2	300
R3	0805	1	20k
U1	RJN_Package_12-Pin_VQFN-HR	1	TPS51386
U2, U3	SOT65P280X110-8N	2	LM74700QDDF*
U4, U5	TPS259803ONRGER	2	TPS259803ONRGER

Warning: *LM74700 exist in different packages. The one used in this design is the 8 pin LM74700D.

Prices (Updated on August 18, 2024)

Example prices on Mouser and JLCPCB.

Shipping is not included.

JLCPCB prices for 5 boards: 1,83 € = 46CZK

Mouser price for 1 board: 28,53 € = 723CZK

Total: 30,36 € = 769CZK

This board costs half the price of the original F1tenth power board...

ID Mouser	ID de fab.	Fabricant	ID client	Description	Qté.	Prix (EUR)	Ext. : (EUR)
595-TPS51386RJNR	TPS51386RJNR	Texas Instruments		4.5-V to 24-V input, 8-A synchronous buck converter 12-VQFN-HR -40 to 125	1	0,967 €	0,97 €
726-IAUCN04S7L005ATM	IAUCN04S7L005ATMA1	Infineon		MOSFET N	2	2,48 €	4,96 €
595-LM74700QDDFRQ1	LM74700QDDFRQ1	Texas Instruments		3.2-V to 65-V, 80-uA IQ automotive ideal diode controller 8-SOT-23-THIN -40 to 125	2	1,66 €	3,32 €
187-CL21A226MAYNNNE	CL21A226MAYNNNE	Samsung Electro-Mechanics		MLCC - CMS 22uF+/-20% 25V X5R 2 0805	10	0,106 €	1,06 €
71-CRCW0805J-20K-E3	CRCW080520K0JNEA	Vishay		CMS 1/8watt 20Kohms 5% 200ppm	10	0,02 €	0,20 €
187-CL21B104KBFNNNE	CL21B104KBFNNNE	Samsung Electro-Mechanics		MLCC - CMS 100n SAMSUNG	10	0,019 €	0,19 €
187-CL21B105MBFNNNE	CL21B105MBFNNNE	Samsung Electro-Mechanics		MLCC - CMS X7R, 1uF, +/-20%, 50v, 0805	10	0,025 €	0,25 €
863-BZX84C3V9LT1G	BZX84C3V9LT1G	onsemi		Zener 3.9V 250mW	1	0,093 €	0,09 €
652-SRP1270-1R5M	SRP1270-1R5M	Bourns		CMS 1.5uH 20% SMD 1270	1	0,911 €	0,91 €
640-USB1130-15-A	USB1130-15-A	Global Connector Technology (GCT)		USB A 2.0 Skt RA High Life 15u" T Hole W/Shell Stake T & R	1	0,735 €	0,74 €
595-TPS259803ONRGER	TPS259803ONRGER	Texas Instruments		Hotswap controller 2.7-V to 24-V, 8-A, 3-mohm smart eFuse 24-VQFN -40 to 125	2	1,43 €	2,86 €
77-VJ0805A220JXACBC	VJ0805A220JXACW1BC	Vishay		MLCC - CMS 0805 22pF 50volts C0G 5%	10	0,052 €	0,52 €
71-CRCW0805-150K-E3	CRCW0805150KFKEA	Vishay		CMS 1/8watt 150Kohms 1% 100ppm	10	0,023 €	0,23 €
187-CL21C103JBFNNNE	CL21C103JBFNNNE	Samsung Electro-Mechanics		MLCC - CMS 10nF+/-5% 50V C0G 20 0805	10	0,105 €	1,05 €
71-CRCW0805620KFKEA	CRCW0805620KFKEA	Vishay		CMS 1/8watt 620Kohms 1%	10	0,031 €	0,31 €
71-CRCW0805300RFKEA	CRCW0805300RFKEA	Vishay		CMS 1/8watt 300ohms 1%	10	0,023 €	0,23 €
71-CRCW08051K00JNEAC	CRCW08051K00JNEAC	Vishay		CMS 1/8Watt 1Kohms 5% Commercial Use	10	0,019 €	0,19 €
710-150080VS75000	150080VS75000	Wurth Elektronik		LED CMS WL-SMCW SMDMono TpVw Waterclr 0805 BrtGrn	5	0,177 €	0,89 €
651-1752492	1752492	Phoenix Contact		Female bornier MSTBA 2,5 HC/ 2-GU	3	0,465 €	1,40 €
651-1892398	1892398	Phoenix Contact		Male bornier MSTB 2,5/ 2-ST- 5,08 BD:NZ KEG	6	1,36 €	8,16 €

Additionals notes

• Copper thickness: 2oz is recommended as batteries can provide high current. But 1oz can be sufficient for the F1tenth car, as it is not used at full power.