Board components

The board features several NXP ICs:

  • MC33772: 6-Channel Li-Ion battery cell controller IC designed for automotive and industrial applications such as HEV, EV, ESS, UPS systems. The MC33772 allows ADC conversions on the differential cell voltages and currents as well as coulomb counting and temperature measurements. It features embedded balancing transistors and diagnostics to simplify applications. The device supports standard SPI and transformer isolated daisy chain communication (via MC33664) to an MCU for processing and control

  • S32K144: AEC-Q100 certified microcontroller for general purpose automotive applications. The S32K144 features an Arm® Cortex®- M4F core, 512 KB of Flash, CAN/CAN-FD controllers, security module complying with SHE specification and is offered in LQFP-48, LQFP-64, LQFP-100 and MAPBGA-100 packages supporting an ambient temperature range from -40°C up to 125°C

  • UJA1169: Mini high-speed CAN System Basis Chip (SBC) containing an ISO 11898-2:201x (upcoming merged ISO 11898-2/5/6) compliant HS-CAN transceiver and an integrated 5V or 3.3V 250 mA scalable supply (V1) for a microcontroller and/ or other loads. It also features a watchdog and a Serial Peripheral Interface (SPI). The UJA1169 can be operated in very low-current Standby and Sleep modes with bus and local wake-up capability

  • A1007: A1007 authentication IC is a secure solution built with many tamper resistant features and security countermeasures to deter common invasive and non-invasive attacks

  • NTAG5: NXP’s NTAG 5 boost shrinks the NFC footprint while adding AES security, so designers can deliver ultra-compact devices for use in IoT, consumer, and industrial applications

IC board location identifiers

The main ICs featured are listed in the table below:

Label

Description

Reference

U1

Battery Cell Controller (BCC)

U2

Micro-Controller Unit (MCU)

U3

System Basis Chip (SBC)

U4

Authentication

A1007

U5

Near-Field Communication (NFC)

Connectors

The following figure shows the location of the connectors on the board.

All connectors implemented on RDDRONE-BMS772 are detailed in the table below:

Label

Description

Manufacturer

Reference

Placed or DNP

JP1

Cell terminal connector

JST MFG. CO

SxB-XH-A(LF)(SN)

DNP

J1

External temperature sensor

JST MFG. CO

SM02B-GHS-TB(LF)(SN)

Populated

J2

JTAG debugger

-

E.g.: FTS-105-01-F-D from SAMTEC

Populated

J3

CAN bus

JST MFG. CO

SM04B-GHS-TB(LF)(SN)

Populated

J4

Battery power input

-

E.g.: FIT0588 from DFRobot

DNP

J5

Battery power output

-

E.g.: FIT0588 from DFRobot

DNP

J6

Reset jumper

FCI

68000-202HLF

Populated with jumper mounted

J18

SMBus (I²C bus)

JST MFG. CO

SM04B-GHS-TB(LF)(SN)

Populated

J19

DCD-LZ debugger

JST MFG. CO

SM07B-GHS-TB(LF)(SN)

Populated

J20

Additional CAN bus

JST MFG. CO

SM04B-GHS-TB(LF)(SN)

Populated

J21

MCU expansion header

HARWIN INC.

M50-3530842

DNP

J22

Wake jumper

FCI

68000-202HLF

DNP

Note: Hardware configuration of the board is done via 16 jumpers to solder (SJxx). See Cell terminal connection, Shunt resistor and External NFC antenna for more details.

Communication with Flight Management Unit

The RDDRONE-BMS772 board can communicate with a host device such as a PX4 Flight controller (FMU) using the SMBus bus (can also be used as a simple I²C bus, connector J18) or the UAVCAN bus (can also be used as a simple CAN bus, connectors J3 and J20).

Note: For further information about UAVCAN, look for enablement in PX4.io software.

Programming and debug

There are two ways to program and debug the RDDRONE-BMS772 board:

  • through the DCD-LZ connector (J19)

  • through the JTAG connector (J2)

Note: The DCD-LZ combines a debug interface with a debug serial console. It is used on RDDRONE-FMUK66 (HoverGames). For more information see the HoverGames gitbook.

LED

The RDDRONE-BMS772 implements a programmable RGB LED. Various color combination and blink patterns can be used to indicate the state of the battery and system.

Button

The side button is a wake button, it connects the WAKE pin of the SBC to the ground when pressed. The J22 header placed in parallel of the side button can be used as an alternative if an extended or panel mount button is needed.

External and additional components

External components

An optional external temperature sensor can be added onto the RDDRONE-BMS772 board using connector J1. An example of application for this external sensor can be to monitor the cells temperature inside the battery pack.

Additional components

Some components are included in the design but are not mounted on the RDDRONEBMS772 original board. They are marked "DNP" on the schematics and the BOM. The following table is giving the list of additional components that can be implemented in the design as well as their use:

Feature

Description

Label

Additional MOSFETs

Q3, Q4, Q7, Q8

Heatsinks

In order to dissipate more power, four additional heat-sinks can be mounted: two on the top side and two on the bottom side of the board. Recommended part is FK 244 08 D2 PAK

HS1, HS2, HS3, HS4

Optional termination resistor network on CAN bus

One 60.4 Ω resistor on each CAN line connected to a 4700 pF capacitor wired to the ground

R49, R50, C66

Capacitors on cell measurements connections

A filter can be added to the cell voltage measurements connections, according to the number of cells in use

C6, C12, C18, C22, C26, C29, C34

Capacitors on external temperature sensor

If the external temperature sensor is implemented, two capacitors can be added on the external temperature sensor low pass filter for more EMC demanding applications

C49, C54

Capacitor on cell balancing connections

Capacitors can be added on the cell balancing circuit for EMC, according to the number of cell in use

C99, C100, C101, C102, C103, C104, C105, C106, C107

External NFC antenna

Coil as an alternative option for the PCB NFC antenna for extended range operations

L2

Resistor on gate driver RS pin

Resistor to link RS pin on gate driver to MCU

R99

MCU expansion header

Additional MCU pins are wired to a 1x8 header slot. Potential to use for local display or additional battery level LEDs

J21

Wake jumper

Jumper for SBC wake-up. In parallel of the button

J22

Test point definitions

The following figure shows the location of the test points on the board.

Label

Signal name

Description

TP1

OVERCURRENT

Overcurrent signal

TP2

AUTH_NFC_SCL

Authentication and NFC I²C bus clock signal

TP3

AUTH_NFC_SDA

Authentication and NFC I²C bus data signal

TP4

VCC_3V3_SBC

SBC 3.3 V regulator output

TP5

RST_N

Reset signal (active low)

TP6

CAN_LO

CAN Low signal

TP7

CAN_HI

CAN High signal

TP8

VCC_3V3_LDO1

LDO 3.3 V regulator output

TP9

SMBUS_SCL

SMBus I²C bus clock signal

TP10

SMBUS_SDA

SMBus I²C bus data signal

TP11

VBAT_IN

Power input

TP12

VBAT_OUT

Power output

TP13

GND

Ground reference of the device

TP14

N/A

Power switches gate command

TP15

N/A

Spare test point. J21[2] pin

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