Atmel AVR365 User manual

Atmel AVR365: ATBM302 Hardware User Guide
Features
• Demonstration system for Atmel®ATBM302
• 5mΩsense resistor current measurements with the 18-bit CC-ADC
• Use pre-programmed IC ATBM302
• Cable connector to cells, load and charger
• Communicate with BM300 via SMBus interface
• The components layout in the top layer and bottom layer
1 Introduction
The Atmel ATBM302-EK is the evaluation and development kit for the new Atmel
AVR®Battery Management device ATBM302. The ATBM302 is a battery
management and protection device for lithium-ion batteries. It can be used for 2S,
3S, and 4S application. The ATBM302-EK monitors cell voltage, charge and
discharge current and cell temperature to protect the battery pack. It also includes
gas gauge to calculate the battery’s capacity.
Figure 1-1. ATBM302-EK kit.
8-bit Atmel
Microcontrollers
Application Note
Rev. 8336A-AVR-03/12

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2 Hardware
The Atmel ATBM302-EK can be divided in two parts: the main area and the
connector area. The main area contains all the components needed in a battery pack.
In the connector area there are four connectors: Cell connector, pack connector, ISP
connector and SMBus connector. Users can connect all the external connections at
these ports. The board size is 100mm × 28.5mm.
Figure 2-1. Main area and connector area.
2.1 Main area
The main area includes all the components used for the battery pack system in the
top layer and bottom layer. Its size is 80mm × 15mm.
2.1.1 Cell balancing
The ATBM302 IC integrates cell balancing FETs. The chip provides one cell
balancing FET for each battery cell in series.
The on-resistance of the cell balancing FET is about 100.
2.1.2 Polarity safety FET
The reverse polarity protection circuit will ensure that the discharge FET (Q3) will turn
off if the charger with reverse polarity connects to the P+ and P-. So the battery can
be ensured to be safe in such cases.
The polarity FET will pull the source of the discharge FET to the negative input
voltage to turn off the discharge FET.

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Figure 2-2. The SCH of polarity circuit.
2.1.3 Pre-charge circuit
The Atmel ATBM302 supports two pre-charge methods: Internal pre-charge and
External pre-charge.
If external pre-charge is selected, the external PCH pads in BM303 should be
connected as shown in Figure 2-3, and the parameter ‘PrechargeCircuitSel’ in SMBus
should be configured to 1.
If internal pre-charge is selected, the two pads must be divided. The charger must in
this case control the pre-charge current – either by sensing the voltage level or by
receiving commands from the BM303 to control the current. The parameter
‘PrechargeCircuitSel’ in SMBus must be configured to 0.
Figure 2-3. Pre-charge switch pad.
2.1.4 LED indication
The LEDs in the battery pack is used to indicate the capacity of battery. When the
switch is pushed down, the LEDs will be on for about three seconds. If the capacity is
from 0% to 20%, LED0 will be on, if battery capacity is from 20% to 40%, LED0 and
LED1 will be on etc.
2.1.5 Fuse blowing
In the BM302 the fuse is not mounted on the PCB, pin 1 and pin 3 of fuse are
connected by polygons. The voltage in the PF test point can be monitored to check if
fuse is blown.
To mount a fuse, please cut the polygon in black rectangle first.

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Figure 2-4. The placement of fuse.
2.1.6 Cell connector
There are two ways to connect cells to the board. Either solder cell wires to the
through-hole pads, or insert cell wires to the connector.
Figure 2-5. Cell connection.
2.1.7 2nd protection IC
In the design an S-8244 IC from Seiko Epson®is used as the 2nd protection IC. If the
voltage of any cell is higher than 4.45V, the S-8244 will send a high voltage signal to
blow the fuse. This action can be detected in PF test point. If the fuse is blown, the PF
voltage will be changed from high to low.
2.2 Connector and pin description
The connectors provide a quick and secure connection to the demonstration board.
2.2.1 Connectors
The following connectors are available:
•Cell connector(1-, 1+, 2+, 3+, 4+)
•Pack connector to P+ and P-
•ISP connector to download firmware to IC
•SMBus communication connector to BM300 (SDA, SCL, GND)

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2.2.2 Pin description
Table 2-1. Cell connector (TB1, TB2).
Name Description
1- Cell1 negative terminal
1+ Cell1 positive terminal, Cell2 negative terminal
2+ Cell2 positive terminal, Cell3 negative terminal
3+ Cell3 positive terminal, Cell4 negative terminal
4+ Cell4 positive terminal
Table 2-2. ISP connector signals (J2).
Name Pin number Description
MISO 1 Serial data out
VCC 2 Supply voltage
SCK 3 Serial clock
MOSI 4 Serial data in
RESET 5 Reset signal (active low)
GND 6 Ground
Table 2-3. Pack connector (TB3).
Name Description
P+ Pack positive terminal
INSYS Battery in system
P- Pack negative terminal
NOTE To turn on the charge and discharge MOSFET, INSYS-pin should be connected to P-.
Table 2-4. SMBus connector (J1).
Name Pin number Description
SDA 1 SMBus data port
SCL 2 SMBus clock port
NC 3-9 Reserved
GND 10 Ground

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3 Platform setup procedure
3.1 Install Battery Studio
Download and install Atmel AVR Battery Studio 2.0 from www.atmel.com/BM300.
3.2 Connection setup
1. Connect the battery cells to BM302 cell terminals
Connect the cells from the bottom of the stack to the top of the stack. For a 3S
application the following connection order must be used: Cell1- to 1- on BM302;
Cell1+ and Cell2- to 1+; Cell2+ and Cell3- to 2+; Cell3+ to 3+. For 3S- packs, 4+ on
BM302 should be connected to 3+.
CAUTION The battery cell terminals polarity and the mounting order must be respected
during assembly and disassembly. When assembling; mount Cell1, then
Cell2, and then Cell3. When disassembling; remove Cell3 first, then Cell2,
and then Cell1.
2. Connect BM300 to BM302 by the 10-pin cable
Figure 3-1. Connect BM300 to BM302.
3. Connect BM300 to PC USB port
The BM300 is powered by USB and the power status is indicated by a red LED near
the USB connector.
3.3 Start the Atmel ATBM302
The ATBM302 device remains in power-off mode although the battery cells have
been connected to the BM302. An external power-up trigger is necessary in order to
power up the ATBM302 device. To start the device a charging voltage must be
applied between pack+ and pack-.
After power-up, the device will perform initialization in the first 30s. During this time,
the reported current will not be correct.
Run the Battery Studio 2.0. Please refer to the Atmel AVR363 Application Note to
learn about how to use Battery Studio 2.

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4 Schematic and board layout
4.1 Schematic
This section shows the schematic for the Atmel ATBM302-EK.
Figure 4-1. ATBM302-EK schematic.
PACK-
VREG
PV2
PV1
NV
CCADC_P
CCADC_N
OD OC VFET
Charge & Discharge MOSFETs
BATT
PVT
GND
PV3
PPI
NNI
GND
LED0
Secondary Protection
Status
LED1
LED2
LED3
LED4
ESD
GND
Sense_PI
Sense_NI
OCG ODG
VREG
PACK-
Polarity safety MOSFET
VREG
RESET
SMB_CLOCK
SMB_DATA
Cell-
PV1R
PV2R
Cell+
WSK25125L000FEA
1
2
4
3
R1
PI
NI
FUSE
PV3R
PV4 PACK+
PACK-
21
MM5Z18VT1G
D3
FUSE
10k
R33
200kR22
VREG
21
BAT54XV2T1G
D12
1 2
3 4
5 6
7 8
910
J1
HEADER 2x5
SMB_CLOCKSMB_DATA
header used for SMBus
1 3
42
SKRAALE010
SW1
10n
C20
1
23
2N7002
Q4
1kR2
1kR5
1kR4
1kR3
1kR11
1kR14
100RR19
100RR12
100RR13
100RR15
100RR16
100RR20
100RR21
10k
R30
10k
R29
10k
R28
10k
R27
22n
C18
1u
C19
LED3
LED4
LED0
LED1
LED2
Fuse
Heater
1
2
3
4
SFH-1412A
F1
1MR51
3
1
2
Si2307Q7
10kR52
100RR6
100RR7
100RR8
100RR9
100RR10
1M
R18
1M
R17
2.2u
C13
1
2
TB1
1
2
3
TB2
1
2
3
TB3
4
3
5
6
7
2
1
8
Q3 Si4168DY
4
3
5
6
7
2
1
8
Q2 Si4168DY
1
2 3
PMV31XN
Q1
R50 150R
Cut track beneath if mounted
1 2
103AT-4T1
1 2
103AT-4T0
200k
R23
100RR42
PACK-
GND
100nF
C1
100nF
C2
100nF
C3
100nF
C4
100nF
C5
100nF
C6
100nF
C7
100nF
C8
100nF
C9
100nF
C10
100nF
C11
100nF
C12
100nF
C15
100nF
C17
100nFC14 100nFC16
100nF
C21
100nF
C22
CO 8
ICT 7
VSS
6
VC3
5
VC2
4
VC1
3
SENSE
2VCC 1
S-8244AAGFN-CEGT2G
U1
C24
1uF
2.4k
R34
5.1kR39
5.1kR38
VREG
FUSE_STATUS
10kR24
OPC
OPC
FUSE_STATUS
SWITCH
SWITCH
3
2 1
AZ23C5V6-7F
D1
GND
VREG
header used for ISP
GND
MISO
SCK
RESET
MOSI
1 2
3 4
5 6
J2
HEADER 2x3
MISO
MOSI
SCK
OCG ODG
1k
R35
21 D5
21 D6
21 D7
21 D8
21 D9
1
2
J3
10nC26
GND
200R
R37
GND
PF
VREG
GND
GND
PV2
40
PV1
41
NV
42
PI
44
NNI
2
Vclmp10
11
OC 18
VFET 12
OD 16
BATT 13
RESET 19
NTC1 8
NTC0 7
VREF 4
VREFGND 3
VREG
6
VCC
14
NC2
17
NC3
27
GND
35
GND
15
GND
5
LED2 22
LED1 21
LED0 20
EXTPORT
29
LED3 23
PV4
38
PV3
39
FUSE 9
INSYS 26
NC 25
LED4 24
ALERT 28
NC
30 FUSE_STATUS
31 SWITCH 10
SDA
32 SCL
33 OPC
34
PPI
43
NI
1
PVT 37
VCC
36
ATBM302
U2
2 1
MM5Z3V3T1G
D2
200RR43
21
BAT54XV2T1G
D10
2 1
BAT54XV2T1G
D11
21
BAT54XV2T1G
D4
10nC23
10nC25
4.2 Components placement
Figure 4-2. The top layer layout.

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Figure 4-3. The bottom layer layout.
4.3 Bill of materials (BOM)
This section shows the BOM for the Atmel ATBM302-EK.
Table 4-1. BOM.
Designator Description Quantity
C1, C2, C3, C4, C5, C6, C7, C8,
C9, C10, C11, C12, C14, C15, C16,
C17, C21, C22
100nF, ceramic capacitor, SMD 0603, X7R, 50V, 10% 18
C13 2.2µF, ceramic capacitor, SMD 0603, X5R, 10V, 10% 1
C18 22nF, ceramic capacitor, SMD 0603, X7R, 50V, 10% 1
C19 1µF, ceramic capacitor, SMD 0603, X5R, 6.3V, 10% 1
C20, C23, C25, C26 10nF, ceramic capacitor, SMD 0603, X7R, 50V, 10% 4
C24 1µF, ceramic capacitor, SMD 0603, X5R, 25V, 10% 1
D1 Dual zener diode, 5.6V, 300mW, SOT23-3 1
D2 Zener diode, SMD SOD-523, 3.3V, 0.2W 1
D3 Zener diode, SMD SOD-523, 18.0V, 0.2W 1
D4, D10, D11 Schottky diode, If:200mA, Vf:0.35V, Vrrm:30V, SOD-523 3
D5, D6, D7, D8, D9 LED, red, wave length = 639nm, SMD 0805 5
D12 Schottky diode, If:200mA, Vf:0.35V, Vrrm:30V, SOD-523 1
J1 2 × 5 pin header, 2.54mm pitch, Pin-in-Paste THM 1
J2 2 × 3 pin header, 2.54mm pitch, Pin-in-Paste THM 1
Q1
N-channel. MOSFET. 20V, 5.9A continuous, 23.7A peak.
RDS(ON) = 0.037@VGS = -4.5V,
RDS(ON) = 0.053@VGS = -2.5V, VGS(th)<1.5V, SOT-23
1
Q2, Q3 N-MOSFET, SO-8, continuous current 16A, Vds = 30V, Vgs = 20V 2
Q4 N-channel MOSFET. 60V, 0.115A continuous, 0.8A peak.
RDS(ON) = 7.5@VGS = 5.0V, VGS(th)<3V 1
Q7
P-channel MOSFET. -20V, -2.4A continuous, -10.0A peak.
RDS(ON) = 100m@VGS = -1.8V,
RDS(ON) = 70m@VGS = -2.5V, VGS(th)<1.5V
1
R1 5mcurrent sense resistor SMD WSK2512 4-terminal 1
R2, R3, R4, R5, R11, R14, R35 1kthick film resistor, SMD 0603, 1/10W, 1% 7
R6, R7, R8, R9, R10, R12, R13,
R15, R16, R19, R20, R21, R42 100thick film resistor, SMD 0603, 1/10W, 1% 13

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R17, R18, R51 1Mthick film resistor, SMD 0603, 1/10W, 1% 3
R22, R23 200kthick film resistor, SMD 0603, 1/10W, 1% 2
R24, R27, R28, R29, R30, R33,
R52 10kthick film resistor, SMD 0603, 1/10W, 1% 7
R34 2.4kthick film resistor, SMD 0603, 1/10W, 1% 1
R37, R43 200thick film resistor, SMD 0603, 1/10W, 1% 2
R38, R39 5.1kthick film resistor, SMD 0603, 1/10W, 1% 2
R50 150resistor, RC2512JK-7W150RL ,YAGEO 1
SW1 6.2mm × 6.2mm SMD tact switch 1
T0, T1 NTC, 103AT-4 2
TB1 Cable connector, 2-pin, through-hole 1
TB2, TB3 Cable connector, 3-pin, through-hole 2
U1 2nd protection IC for 1-4S, 8-leds, MSOP 1
U2 Pre-program ATBM302 1

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5 EVALUATION BOARD/KIT IMPORTANT NOTICE
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DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES ONLY. It is
not a finished product and may not (yet) comply with some or any technical or legal
requirements that are applicable to finished products, including, without limitation,
directives regarding electromagnetic compatibility, recycling (WEEE), FCC, CE or UL
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