WM330 Battery Intelligent Board

Table of Contents

Function
Variants
Parts
Programming
External interfaces
Service interfaces
Board view
Schematics

Function

DJI Intelligent Flight Battery for Phantom 4 is a 5870mAh, 15.2V LiPo-4s battery, supporting up to 28 minutes of flight time. The battery also has built-in sensors and bright LEDs that let you know the status and remaining power. It contains automatic discharge feature to avoid swelling (fully charged LiPo cells release hydrogen), and Permanent Failure feature which disables the battery in case of damage or unexpected behavior of cells.

The battery management system chip (TI BQ30Z55) is queried for data by a small micro-controller (TI MSP430) through a Smart Battery System protocol. That micro-controller sends updates to the FC in regard to current battery status.

The SBS protocol defines battery-related commands to be transferred over SMBus, which in turn is deviced from I2C.

Variants

There are multiple versions of the board.

Marking	Overview
P01438.06

Parts

Version P01438.06 components

Marking	Amt.	Pkg.	Function	Specification
MSP430 G2755	1		Texas Instruments MSP430 MCU is used to control the battery and external interfaces.	description datasheet
BQ30Z55	1	TSSOP-30	Integrated 2-Series, 3-Series, and 4-Series Li-Ion or Li-Polymer Cell Battery Pack Manager and Protection; the specific chip was only made available by TI for a few customers, but it is very similar to BQ30Z554. Also, its spec can be found in various places (sluu852a.pdf).	description applc.note
10-slab EXT PWR	1		MSD-DB01F-10P, MISTA 10A pitch 2.5mm 10 pin connector	description

Programming

Chips	Firmware	Description
BQ30Z55		Battery control chip; it has firmware, but that is not publicly available.
MSP430		Small micro-controller which queries the BQ30Z55 for battery status and sends the information to Flight Controller.

External interfaces

Connectors on the board are:

Marking	Overview
10-slab EXT PWR	External connector of the battery; provides power input and output, and serial interface.

External connector of the battery

Here is the connector pinout:

Pin	Label	Function
1	UART_RX/UART_TX?
2	GND	Ground
3	GND
4	PACK+	+15.2V from battery cells
5	PACK+
6	PACK+
7	PACK+
8	GND
9	GND
10	UART_TX/UART_RX?

Service interfaces

The following service pads exist on this board:

Marking	Overview
TODO

Board view

Top of a P01438.06 board:

Bottom of the P01438.06 board:

Schematics

Functional diagram

flowchart LR
    Connector-BAT((batt<br/>connec<br/>tor))
    subgraph Battery Intelligent board
    direction LR
    BatteryMCU[MSP430 MCU<br/>Battery<br/>interface<br/>control]
    BatteryBMS[BQ30Z55 BMS<br/>Li-Po pack<br/>manager]
    BattFeedbackR(0.02 Ohm<br/>feedback<br/>resistor)
    BatteryButton(button)
    BatteryLEDs(LED line)
    BatteryMCU-- GPIO ---BatteryButton
    BatteryMCU-- GPIO ---BatteryLEDs
    EnablePackFET(MOSFET<br/>output<br/>control)
    EnableChargeFET(MOSFET<br/>charge<br/>enable)
    EnableDischargeFET(MOSFET<br/>internal<br/>discharge<br/>enable)
    DischargeR(discharge<br/>resistor)
    DischargeR---EnableDischargeFET
    BatteryBMS-- DSG ---EnableDischargeFET
    BatteryMCU-- SMBus ---BatteryBMS
    BatteryBMS-- GPOD ---EnablePackFET
    BatteryBMS-- CHG ---EnableChargeFET
    end
    subgraph Li-Po cells pack
    direction TB
    BatteryCell1(battery<br/>cell 1)
    BatteryCell2(battery<br/>cell 2)
    BatteryCell3(battery<br/>cell 3)
    BatteryCell4(battery<br/>cell 4)
    BatteryTempSense(NTC<br/>thermistor)
    BatteryCell1===BatteryCell2
    BatteryCell3===BatteryCell2
    BatteryCell4===BatteryCell3
    end
    BattFeedbackR===BatteryCell1
    BatteryBMS-- VSS ---BatteryCell1
    BatteryBMS---BatteryCell2
    BatteryBMS---BatteryCell3
    BatteryBMS---BatteryCell4
    Connector-BAT== PACK- ===BattFeedbackR
    BatteryBMS-- SRn ---BattFeedbackR
    BatteryBMS-- TS ---BatteryTempSense
    EnableDischargeFET===BatteryCell4
    EnablePackFET===EnableDischargeFET
    EnableChargeFET===EnableDischargeFET
    Connector-BAT== PACK+ ===EnablePackFET
    Connector-BAT== PACK+ ===EnableChargeFET
    Connector-BAT-- UART ---BatteryMCU

Thick lines are the ones transferring high power. Feedback resistor for measuring current is inserted into negative line, while all the MOSFET switches are within positive line. The four Li-Po cells are connected in series, so that the voltage sums up.

The Battery Management System chip is not designed to have any user interface, so that is handled by the additional micro-controller. The MCU communicates with BMS using the protocol described in Smart Battery Specification, over SMBus interface. The charge level, as well as errors retieved from the BMS, can be shown on attached line of four LEDs. The MCU can also read button state, and ask the BMS to start or shutdown the power delivery.

Hardware schematics

No schematics available.