BM3451 [ETC]
3/4/5 Cell Battery Protectors;
| 型号： | BM3451 |
| 厂家： | 
ETC |
| 描述： | 3/4/5 Cell Battery Protectors 电池 |
| 文件： | 总28页 (文件大小：782K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
BM3451 Series
3/4/5 Cell Battery Protectors
BYD Microelectronics Co., Ltd.
General Description
The BM3451 is a professional protection IC for 3/4/5 cells rechargeable battery pack; it is highly
integrated, and generally used in power tools, electric bicycles and UPS applications.
The BM3451 works constantly to monitor each cell’s voltage, the current of charge or discharge, and
the temperature of the environment to provide overcharge, over-discharge, discharge overcurrent, short
circuit, charge overcurrent and over-temperature protections, etc. Besides, it also can change the
protection delay time of overcharge, over-discharge and discharge overcurrent by setting the external
capacitors.
The BM3451 provides external bleeding for cell-capacity balance function to avoid unbalanced
capacity between each cell. Thus, the batteries can work for longer.
Extended function module embedded in the BM3451 ICs can make them work for more battery packs
with multiple chips, and they can protect 6-cell batteries or more than 6-cell batteries.
Features
(1) High-accuracy voltage detection for each cell
·overcharge threshold
3.6V~4.6V
accuracy: ±25 mV (+25℃)
accuracy: ±40 mV (-40℃ to +85℃)
accuracy: ±50 mV
·overcharge hysteresis
·over-discharge threshold
·over-discharge hysteresis
0.1V
1.6V~3.0V
accuracy: ±80 mV
0V / 0.2V / 0.4V accuracy: ±100 mV
(2) Three grades voltage detection of discharge overcurrent
·discharge overcurrent 1
·discharge overcurrent 2
·short circuit
0.025 V ~ 0.30 V
(50 mV step)
0.2 V / 0.3V / 0.4V / 0.6 V
0.8V / 1.2 V
(3) Charge overcurrent detection
·detection voltage
-0.03V / -0.05V / -0.1V / -0.15V / -0.2 V
(4) 3/4/5 cell protection enable
(5) Setting of output delay time
·overcharge, over-discharge, discharge overcurrent 1 and discharge overcurrent 2 protection delay
time can be set by external capacitors
(6) Supports external bleeding for balance
(7) Controlling the state of charge or discharge by external signals
(8) The maximum output voltage of CO / DO: 12V
(9) Over-temperature protection
(10) Breaking wire protection
(11) Low power consumption
·operation mode（with Temp protection）
·operation mode（without Temp protection）
·sleeping mode
25 μA typical
15 μA typical
6 μA typical
Datasheet
WI-D06-J-0036 Rev.A/1
1 / 28
BYD Microelectronics Co., Ltd.
BM3451 Series
Applications
·Power tool
·Electric bicycle
·UPS backup battery
Packages
·TSSOP28
·TSSOP20
Block Diagram
VCC
Balance
BALUP
Control 1
VC5
BAL5
VC4
OR
CO DO
Series
DOIN
COIN
TOV
TOVD
TOC1
TOC2
BAL4
VC3
External
DelayTime
Logic Circuit
BAL3
VC2
NTC
TRH
TEMP
Protection
BAL2
VC1
Charger /
Load
Detection
VM
CO DO
Driver
CO
DO
BAL1
GND
SET
OR
Balance
Control 2
BALDN
VIN
3/4/5 Cell
selection
Dsicharge
overcurrent
Detection
OCCT
Figure 1
Datasheet
WI-D06-J-0036 Rev.A/1
2 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Selection Guides
1. Products name structure
Figure 2
2. Products catalogue
Overcharge Overcharge
Over-
Over-
Discharge
Discharge
Short
circuit
Charge
Balance
protection
voltage
release
voltage
discharge discharge overcurrent overcurrent
overcurrent detection
Type/Item
protection
voltage
release
voltage
1 detection 2 detection detection
voltage voltage voltage
[VOC1 [VOC2
detection
voltage
voltage
[VDET1
]
[VREL1
]
[VDET2
]
[VREL2
]
]
]
[VSHORT
]
[VOVCC
]
[VBAL]
BM3451VJDC-T28A
BM3451SMDC-T28A
BM3451HEDC-T28A
BM3451VJDC-T20A
BM3451SMDC-T20A
BM3451HEDC-T20A
4.300V
4.225V
3.850V
4.300V
4.225V
3.850V
4.200V
4.125V
3.750V
4.200V
4.125V
3.750V
2.500V
2.800V
2.000V
2.500V
2.800V
2.000V
2.700V
3.000V
2.500V
2.700V
3.000V
2.500V
Table 1
0.100V
0.100V
0.100V
0.100V
0.100V
0.100V
0.400V
0.400V
0.400V
0.400V
0.400V
0.400V
0.800V
0.800V
0.800V
0.800V
0.800V
0.800V
-0.100V
-0.100V
-0.100V
-0.100V
-0.100V
-0.100V
4.120V
4.050V
3.590V
-
-
-
Datasheet
WI-D06-J-0036 Rev.A/1
3 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Pin Configurations
Figure 3
Pin Definition
TSSOP28
TSSOP20
Name
Description
Pin number Pin number
1
2
3
-
BALUP
DOIN
Balance signal transfer terminal 1
1
2
DO controller for extended application
COIN
CO controller for extended application
Connect to a capacitor for setting the delay time of
overcharge protection
4
5
6
7
3
4
5
6
TOV
TOVD
TOC1
TOC2
Connect to a capacitor for setting the delay time of
over-discharge protection
Connect to a capacitor for setting the delay time of discharge
overcurrent 1 protection
Connect to a capacitor for setting the delay time of discharge
overcurrent 2 protection
8
7
8
NTC
TRH
VM
Cell temperature detection
9
Temperature protection reference
10
11
12
9
Voltage detection terminal 1 for detecting load or charger
Charge power mosfet control terminal, Open-Drain output
Discharge power mosfet control terminal, CMOS output
10
11
CO
DO
Datasheet
WI-D06-J-0036 Rev.A/1
4 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
13
14
-
BALDN
VIN
Balance signal transfer terminal 2
Charge and Discharge overcurrent Voltage detection
terminal 2
12
15
16
17
18
19
20
21
22
23
24
25
26
27
28
-
OCCT
SET
Discharge overcurrent release control terminal by load
13
14
-
Select terminal for 3/4/5 cell application
Ground pin of the IC, Cell1 negative input
Cell1 external bleeding control
Cell1 positive input, Cell2 negative input
Cell2 external bleeding control
Cell2 positive input, Cell3 negative input
Cell3 external bleeding control
Cell3 positive input, Cell4 negative input
Cell4 external bleeding control
Cell4 positive input, Cell5 negative input
Cell5 external bleeding control
Cell5 positive input
GND
BAL1
VC1
15
-
BAL2
VC2
16
-
BAL3
VC3
17
-
BAL4
VC4
18
-
BAL5
VC5
19
20
VCC
Power supply,Cell5 positive input
Table 2
Absolute Maximum Ratings
Item
Symbol
Description
-
Ratings
Unit
V
Power supply voltage
VCC
GND-0.3 ~ GND+30
Vcell5,Vcell4,Vcell3
Vcell2,Vcell1
Single cell input voltage
VCELL
GND-0.3 ~ GND+6
V
VM input voltage
DO output voltage
CO output voltage
Operating temperature
Storage temperature
VM
VDO
VCO
TA
VM
DO
CO
-
GND-20 ~ GND+30
GND-0.3 ~ VCC+0.3
GND-20 ~ VCC+0.3
-40 ~ 85
V
V
V
℃
℃
TSTG
-
-40 ~ 125
Table 3
Caution: The absolute maximum ratings are rated values exceeding which the product could suffer
physical damage. These values must therefore not be exceeded in any conditions.
Datasheet
WI-D06-J-0036 Rev.A/1
5 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Electrical Characteristics
（TA=25℃ unless otherwise specified）
Test
Item
Symbol
Test conditions*1
Min.
Typ.
Max.
Unit
circuit
Power supply voltage
Operating consumption
Sleeping consumption
VCC
ICC
ISLP
-
5
-
-
-
-
-
30
25
10
V
1
V1=V2=V3=V4=V5=3.5V
V1=V2=V3=V4=V5=2.0V
μA
μA
Protection
threshold
V1=V2=V3=V4=3.5V
VDET1
VDET1
VDET1
VDET1
1.0
V
s
V5=3.5→4.4V
-0.025
+0.025
Protection
delay time
V1=V2=V3=V4=3.5V
TOV
0.5
1.5
COV=0.1μF V5=3.5V→4.4V
Release
Overcharge
V1=V2=V3=V4=3.5V
VREL1
-0.05
VREL1
+0.05
VREL1
TREL1
KU1
VREL1
V
threshold
V5=4.4V→3.5V
Release
V1=V2=V3=V4=3.5V
10
20
30
ms
mV/℃
V
delay time
V5=4.4V→3.5V
Temperature
factor(1)
-0.6
0
0.6
Ta= -40℃ to 85℃
2
Protection
threshold
V1=V2=V3=V4=3.5V
VDET2
-0.08
VDET2
+0.08
VDET2
VDET2
V5=3.5V→2.0V
V1=V2=V3=V4=3.5V
COVD=0.1μF
Protection
TOVD
0.5
1.0
1.5
s
delay time
Over-
V5=3.5V→2.0V
discharge
Release
V1=V2=V3=V4=3.5V
VREL2
-0.10
VREL2
+0.10
VREL2
TREL2
VOC1
TOC1
VREL2
V
threshold
V5=2.0V→3.5V
Release
V1=V2=V3=V4=3.5V
10
20
30
ms
V
delay time
V5=2.0V→3.5V
Protection
threshold
V1=V2=V3=V4=V5=3.5V
VOC1
VOC1
VOC1
200
200
V6=0V→0.12V
*85%
*115%
Protection
delay time
V1=V2=V3=V4=V5=3.5V
100
100
300
300
ms
ms
C
OC1=0.1μF V6=0V→0.12V
Discharge
overcurrent
1
Release
V1=V2=V3=V4=V5=3.5V
TROC1
delay time
V6=0V→0.12V→0V
Resistance
between VM
and GND
V1=V2=V3=V4=V5=3.5V
RVMS
100
-0.1
300
500
0.1
kΩ
3
V6=0V→0.12V
Temperature
factor(2)
KU2
VOC2
TOC2
0
Ta= -40℃ to 85℃
mV/℃
V
Protection
threshold
V1=V2=V3=V4=V5=3.5V
VOC2
VOC2
VOC2
20
Discharge
overcurrent
2
V6=0V→0.5V
*80%
*120%
Protection
delay time
V1=V2=V3=V4=V5=3.5V
10
30
ms
C
OC2=0.1μF V6=0V→0.5V
Datasheet
WI-D06-J-0036 Rev.A/1
6 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
VSHORT
*80%
VSHORT
Protection
threshold
V1=V2=V3=V4=V5=3.5V
VSHORT
VSHORT
TSHORT
VOVCC
TOVCC
V
μs
V
*120%
V6=0V→1.2V
Short circuit
3
4
Protection
delay time
V1=V2=V3=V4=V5=3.5V
100
300
VOVCC
20
600
V6=0V→1.2V→0V
Protection
threshold
V1=V2=V3=V4=V5=3.5V
VOVCC
-0.03
VOVCC
+0.03
V6=0V→-0.2V
Charge
overcurrent
Protection
delay time
V1=V2=V3=V4=V5=3.5V
10
30
ms
V6=0V→-0.2V
External bleeding voltage
for balance
V1=V2=V3=V4=3.5V
VBAL
VBAL
VBAL
RCO
VBAL
V
5
6
V5=3.5V→4.30V
-0.05
+0.05
CO
Normal time, Co ”H” (12V)
3
3
5
5
8
8
kΩ
Normal time, Do ”H” (12V)
DO
RDO
kΩ
7
Protecting time, Do ”L”
On ”H”
0.20
1.4
0.5
1.4
0.5
1.4
0.5
1.4
0.5
1.4
0.5
0.35
2.0
0.8
2.0
0.8
2.0
0.8
2.0
0.8
2.0
0.8
0.50
2.6
1.1
2.6
1.1
2.6
1.1
2.6
1.1
2.6
1.5
BAL1
RBAL1
RBAL2
RBAL3
RBAL4
RBAL5
Off ”L”
On ”H”
BAL2
BAL3
BAL4
BAL5
Output
Off ”L”
resistances
On ”H”
kΩ
8
Off ”L”
On ”H”
Off ”L”
On ”H”
Off ”L”
Table 4
*1: All the test condition parameters above are designed based on Li+ parameters, other grade parameters
can adjust by their own actual voltages.
Datasheet
WI-D06-J-0036 Rev.A/1
7 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Function Description
1. Overcharge
During charging, VIN >VOVCC when IC doesn’t work in the state of charge overcurrent, If any of VC1,
(VC2-VC1), (VC3-VC2), (VC4-VC3) and (VC5-VC4) is higher than VDET1 and lasts longer than TOV,
BM3451 chip considers that the batteries work in the state of overcharge, the output voltage of CO will
become to high resistance from high level, and then it will be pulled down to low level by external resistor.
The charge MOSFET will be turned off and stop charging.
The overcharge protection state will be released if any of the next conditions occurs:
(1) All cells’ voltage is less than the Overcharge release threshold VREL1 and stays a period of time
TREL1.
(2) VM> 100mV (connecting to the load), Battery voltage is lower than VDET1 and stays a period of time
TREL1.
2. Over-discharge
During discharging, VIN<VOVCC when IC doesn’t work in the state of discharge overcurrent. If any of
VC1, (VC2-VC1), (VC3-VC2), (VC4-VC3) and (VC5-VC4) is less than VDET2 and lasts longer than TOVD
.
BM3451 chip considers that the batteries work in the state of over-discharge and the output voltage of DO
will turn to GND. The discharge MOSFET will be turned off and stop discharging, then the chip will enter
sleeping mode.
The over-discharge protection state will be released if any of the next conditions occurs:
(1) VM =0mV, all cells’ voltage is higher than VREL2 and stays a period of time TREL2.
(2) VM <-100mV (connecting to the charger), all cells’ voltage is higher than VDET2 and stays a period of
time TREL2.
3. Discharge Overcurrent
During discharging, the current varies with the load. The voltage of VIN becomes higher with the current
increasing. When the voltage of VIN is higher than VOC1 and stays longer than TOC1, we think the IC works in
the state of discharge overcurrent 1; When the voltage of VIN is higher than VOC2 and stays longer than
T
OC2, we consider the IC works in the state of discharge overcurrent 2; When the voltage of VIN is higher
than VSHORT and stays longer than TSHORT, we think the IC works in the state of short circuit. When any of the
three states occurs, the output voltage of DO changes to low level to turn off the discharge MOSFET and
stop discharging. At the same time, RVMS which is the inner pulling down resistance of VM is connected,
and we know that VM is pad which we can lock the output voltage of DO by when chip works in the state of
over-current discharge. Usually VOC1 < VOC2 < VSHORT, TOC1 > TOC2 > TSHORT .When IC works in discharge
overcurrent, the output voltage of DO is locked in low level. The discharge overcurrent protection state will
be released when disconnect the load.
4. Delay Time Setting
Overcharge and Over-discharge delay time can be calculated as follow:
Tov = 107 x COV; Tovd = 107 x COVD
Discharge overcurrent 1 delay time can be calculated as follow: Toc1 = 2 x 106 x COC1
Discharge overcurrent 2 delay time can be calculated as follow: Toc2 = 2 x 105 x COC2
Datasheet
WI-D06-J-0036 Rev.A/1
8 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
5. Charge Overcurrent
During charging, if the current is biggish with VIN<VOVCC and stays longer than TOVCC, the BM3451 chip
considers that the batteries work in the state of charge overcurrent, the output voltage of CO will be pulled
down to low level and the charge MOSFET will be turned off and stop charging. Charge overcurrent
protection will be released when we disconnect the charger.
6. Balance Function
Cells’ balance function is used to balance the cells’ capacity in a pack. When all voltages of VC1,
(VC2-VC1), (VC3-VC2), (VC4-VC3) and (VC5-VC4) are lower or higher than VBAL , all the external balance
discharge circuits will not work. Otherwise the cell, whose voltage is higher than VBAL, will turn on the
external discharge circuit and make its voltage lower than VBAL. During charging, If the highest voltage of
five cells enters overcharge state and its cell balance circuit turns on, the charge control MOSFET turns off
and the external discharge circuit works and makes the battery voltage fall down to VREL1 which is the
overcharge release threshold, then turn on the charge control MOSFET for continuing charge .For a long
enough time of charge and discharge cycles, the voltages of all cells will reach to more than VBAL, and avoid
the capacity differences between batteries.
7. Over-temperature
Usually, batteries should be prevented charging and discharging from over-temperature. The BM3451
chip has this over-temperature protection. The thermostat resistor connecting to NTC pad is used to induct
the pack’s temperature, the resistor connecting TRH pad is used to set the reference of over-temperature
protection. Assuming the resistance of NTC is RNTC when the pack gets to the temperature of charge
over-temperature protection, and then we set the resistance RTRH of TRH be RTRH =2* RNTC. The
over-discharge protection temperature is the temperature when the resistance of NTC become to 0.54*
R
NTC. We can set the temperature of charge and discharge protection by changing the value of RTRH
.
Take 103AT-4 for example, NTC resistance is 10KΩ in normal temperature (25℃), and the temperature
of charge over-temperature protection is 55℃.When the temperature is 55℃ and chip works in the state of
charging, RNTC is 3.5KΩ, so RTRH is equal to 7KΩ. We also know the NTC resistance is 0.54*RNTC=1.89 KΩ
when the pack arrive to the temperature of discharge over-temperature, the temperature is 75℃ in this
condition. The hysteresial temperature of charge over-temperature is 5℃ and the hysteresial temperature
of discharge over-temperature is 15℃. During charging, when the temperature is higher than 55℃, the
output voltage of CO turns to high resistance, and will be pulled down to low level by external resistor,
charge control MOSFET will be turned off and stops charging. And when the pack’s temperature falls down
to 50℃, CO changes to high level and charge control MOSFET be turned on again. During discharging,
when the temperature is higher than 75℃, the output voltage of DO becomes to low level, discharge
control MOSFET will be turned off and stop discharging, at the same time charge control MOSFET will also
be turned off and stops charging. When pack’s temperature falls down to 60℃, the output of CO and DO
turn to high level, charge and discharge control MOSFET will both be turned on again.
8. Breaking wire protection
When one or multi wires of VC1, VC2, VC3, VC4 and VC5 are detected cut from the batteries by the
BM3451 chip, the IC will consider it enters a state of breaking wire, then CO will be in high resistance and
DO will turn to GND level, then the IC enters low consumption state.
When the breaking wires are connected correctly again, the IC will exit breaking wire protection.
Specially attention, regardless one chip application or multi-chip application, the GND pin must not be open
from the battery, or the IC cannot operate normally, and it cannot protect correctly.
Datasheet
WI-D06-J-0036 Rev.A/1
9 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
9. 3/4/5 cells application selection
SET voltage
Floating
VCC
Cells
Short pins
-
5
4
3
VC1=GND
GND
VC1=VC2=GND
Chart 5
10.Extended application
When the BM3451 chip is used in extended condition, each IC transfers its information of overcharge,
over-discharge, and balance to neighboring ICs. Take application of figure 6 for example, the information of
DO and CO of IC1 will transfer to DOIN and COIN of IC2, then IC2 control external MOSFETs turn on or
turn off by the voltage of DOIN and COIN. DOIN and COIN have precedence to control DO and CO over
internal protection signals. Balance information transfer by BALUP and BALDN, IC follows the rule that
inner balance has precedence over external balance.
Take extended application of three ICs with A, B, C for example, the external rule of balance is as
follows:
Balance of A
(ON or OFF)
OFF
Balance of B
(ON or OFF)
OFF
Balance of C
(ON or OFF)
OFF
A
B
C
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
OFF
OFF
ON
OFF
ON
OFF
OFF
ON
ON
ON
OFF
OFF
ON
OFF
ON
ON
ON
OFF
OFF
OFF
OFF
Signal descriptions: “1” shows that any of the batteries is equal to or above VBAL, “0” shows that at least
one of the batteries is lower than VBAL.
Datasheet
WI-D06-J-0036 Rev.A/1
10 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Operation Timing Charts
1. Overcharge/Over-discharge Protection
VDET1
VREL1
VCELL
VREL2
VDET2
VCC
12V
VCO
GND
VCHR-
VCC
12V
VDO
GND
VCHR-
VCC
VM
GND
VCHR-
Connecting to load
Connecting to charger
TDET1
TDET2
(1)
(2)
(1)
(3)
(1)
Figure 4
Assuming the charging current is constant, VCHR- is the voltage of the charger’s negative terminal:
（1）Normal condition;
（2）Overcharge protection state;
（3）Over-discharge protection state.
Datasheet
WI-D06-J-0036 Rev.A/1
11 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
2. Discharge Overcurrent / Short Circuit / Charge Overcurrent Protection
VDET1
VREL1
VCELL
VREL2
VDET2
VCC
12V
VCO
GND
VCHR-
VCC
12V
VDO
GND
VCHR-
VCC
VM
GND
VCHR-
VCC
VSHORT
VIN
VOC2
VOC1
GND
VOVCC
VCHR-
Connecting to load
Connecting to charger
TOC2
(1)
TSHORT
TOVCC
TOC1
(1)
(2)
(3)
(1)
(4)
(1)
(5)
(1)
Figure 5
Assuming the charging current is constant, VCHR- is the voltage of the charger’s negative terminal:
（1） Normal condition;
（2） Discharge overcurrent 1 protection state;
（3） Discharge overcurrent 2 protection state;
（4） Short circuit protection state;
（5） Charge overcurrent protection state.
Datasheet
WI-D06-J-0036 Rev.A/1
12 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Application Circuits
1. Single chip application
Figure 6（a-1）5-cell application (SET floating)
---with balance function, charge and discharge circuits together
Figure 6（a-2）5-cell application (SET floating)
---with balance function, charge and discharge circuits separated
Datasheet
WI-D06-J-0036 Rev.A/1
13 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Figure 6（b）4-cell application (SET be connected to VCC) ---with balance function
Figure 6（c）3-cell application (SET be connected to GND)---with balance function
Datasheet
WI-D06-J-0036 Rev.A/1
14 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Figure 6（d-1）5-cell application (SET floating)
---without balance function, charge and discharge circuits together
Figure 6（d-2）5-cell application (SET floating)
---without balance function, charge and discharge circuits separated
Datasheet
WI-D06-J-0036 Rev.A/1
15 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Figure 6（e）4-cell application (SET be connected to VCC) ---without balance function
Figure 6（f）3-cell application (SET be connected to GND) ---without balance function
Datasheet
WI-D06-J-0036 Rev.A/1
16 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Constants for External Components：
Component Symbol
Typ.
Range
100 ~ 1000
3~10
Unit
Ω
R1, R2, R3, R4, R5
1000
4.7
1000
1
RB1, RB2, RB3, RB4, RB5
MΩ
Ω
RVCC
100 ~ 1000
1 ~ 2
R6, R7
MΩ
Ω
R8, R9, R10, R11, R12
47
10
7
10 ~ 200
-
RNTC
kΩ
kΩ
kΩ
MΩ
kΩ
mΩ
μF
RTRH
RVM
-
220
10
2
10-500
5~15
RCO, RS
RDO
1~10
Rsense
5
1 ~ 20
10 ~ 100
CVCC
10
1.0
0.1
C1, C2, C3, C4, C5
0.1 ~ 10
Maximum
μF
endurable
COV, COVD, COC1, COC2
-
μF
voltage >50V
Table 6
Datasheet
WI-D06-J-0036 Rev.A/1
17 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
2. Two chips extended application
P+
RVCC2
R10
CVCC2
C10
R20
R19
R18
R17
R16
RB10
RB9
RB8
RB7
RB6
V10
V9
V8
V7
V6
R23
R9
R8
R7
R6
C9
R24
VCC
VC5
BALUP
1
2
3
4
5
6
7
8
28
27
26
25
24
C8
DOIN
COIN
BAL5
VC4
COV2
TOV
COVD2
TOVD
BAL4
C7
TOC1
23 VC3
BAL3
TOC2
22
21
20
19
18
17
16
15
BM3451
NTC
TRH
VM
VC2
BAL2
9
C6
VC1
10
11
12
13
14
CO
BAL1
DO
GND
BALDN
VIN
SET
Rp
OCCT
P1
RVCC1
R5
CVCC1
R25
R21
C5
R15
R14
R13
R12
R11
RB5
R22
V5
V4
V3
V2
V1
R4
R3
R2
R1
C4
RB4
RB3
RB2
RB1
CDOIN
VCC
BALUP
DOIN
COIN
TOV
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
CCOIN
C3
VC5
BAL5
COV1
COVD1
COC1
COC2
VC4
TOVD
TOC1
TOC2
NTC
BAL4
C2
VC3
D2
BAL3
BM3451
RNTC
VC2
RTRH
BAL2
TRH
M1
RVM
C1
VM
VC1
CO
BAL1
DO
GND
D1
BALDN
VIN
SET
RCO
OCCT
RDO
Rsense
P–
RS
Figure 7 10-cell application——with balance function
Datasheet
WI-D06-J-0036 Rev.A/1
18 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
P+
RVCC2
CVCC2
R23
R10
C10
V10
R24
R9
V9
C9
R8
C8
V8
DOIN
VCC
VC5
VC4
VC3
VC2
VC1
GND
SET
VIN
1
2
3
4
5
6
7
8
9
20
19
18
17
16
15
14
13
12
11
COIN
COV2
R7
TOV
V7
C7
COVD2
TOVD
TOC1
R6
BM3451
TOC2
NTC
TRH
VM
V6
C6
CO
DO
10
Rp
P1
CVCC1
RVCC1
R5
R22
R21
V5
C5
R25
R4
V4
C4
CDOIN
R3
CCOIN
V3
C3
DOIN
COIN
TOV
VCC
VC5
VC4
VC3
VC2
VC1
GND
SET
VIN
1
2
3
4
5
6
7
8
9
20
19
18
17
16
15
14
13
12
11
COV1
COVD1
COC1
COC2
R2
R1
V2
V1
C2
D2
TOVD
TOC1
TOC2
NTC
TRH
VM
BM3451
C1
RNTC
RTRH
RVM
M1
CO
DO
10
D1
RCO
RDO
Rsense
P–
RS
Figure 8 10-cell application——without balance function
Caution：The maximum endurable voltage of the MOS M1, the diode D1, D2 and the transistor P1 must
be more than the total voltage of the whole battery packages, and keep enough voltage room.
Above of 4-cell, 3-cell, and 10cell applications are charge and discharge circuits together,
charge and discharge separated circuits can refer to 5-cell application.
Datasheet
WI-D06-J-0036 Rev.A/1
19 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Constants for External Components：
Component Symbol
R1, R2, R3,R4, R5,
R6,R7, R8, R9, R10
RB1, RB2, RB3, RB4, RB5,
RB6, RB7, RB8, RB9, RB10
RVCC1, RVCC2
Typ.
Range
Unit
1000
100 ~ 1000
Ω
4.7
1000
47
3 ~ 10
100 ~ 1000
10 ~ 200
MΩ
Ω
R11, R12,R13, R14, R15,
R16, R17, R18, R19, R20
R21, R22, R25
R23, R24, RP
Ω
10
1
8 ~ 15
1 ~ 2
-
MΩ
MΩ
kΩ
RNTC1, RNTC2
10
7
RTRH1,RTRH2
-
kΩ
RVM
200
10
2
10-500
5~15
0~10
0.1 ~ 20
kΩ
RCO, RS
MΩ
kΩ
RDO
Rsense
5
mΩ
μF
CVCC1, CVCC2
10
10 ~ 100
C1, C2, C3, C4, C5,
C6, C7, C8, C9, C10
0.1
0 ~ 0.33
μF
Maximum
endurable
COV1, COVD1, COV2, COVD2
OC1, COC2
CDOIN, CCOIN
,
voltage >50V
0.1
33
-
μF
C
33~100
nF
Table 7
Datasheet
WI-D06-J-0036 Rev.A/1
20 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Test Circuits
The next tests take 5-cell application for example, so that SET pin is floating. If 4-cell application is
selected, we set SET pin to VCC level and force GND voltage level to VC1; else if 3-cell application is
selected, we set SET pin to GND level and force GND voltage level to VC1 and VC2. The test methods of
4-cell and 3-cell application are as same as 5-cell application.
1. Normal and Sleeping Current Consumption
Test circuit 1
(1) Set V1=V2=V3=V4=V5=3.50V, the current flowing to GND is the normal operating current
consumption.
(2) On the condition of (1), then set V1=V2=V3=V4=V5=2.0V, the current flowing to GND is the
sleeping current consumption.
2. Overcharge Protection Test
Test circuit 2
2.1 Overcharge threshold (VDET1) and Overcharge release threshold (VREL1
)
Set V1=V2=V3=V4=V5=3.50V, make sure the output voltages of DO and CO pins are “H” level.
Increase V5 gradually, monitor CO voltage and keep the condition not shorter than Tdet1, the value
of V5 when CO turns from “H” to “L” is the overcharge threshold voltage. Decrease V5, the V5
when CO returns to “H” level again is the overcharge release threshold.
2.2 Overcharge protection delay time and Overcharge release delay time
(1) Set V1=V2=V3=V4=V5=3.50V, make sure the output voltages of DO and CO pins are “H” level.
Increase V5 to 4.4V from 3.5V instantaneously, monitor CO voltage and keep a period of time. The
time interval when CO turns from “H” to “L” is the overcharge protection delay time.
(2) Set V1=V2=V3=V4=3.50V, V5=4.4V, make sure the output voltage of DO is “H” level, CO is “L”
level. Decrease V5 to 3.5V from 4.4V instantaneously, monitor CO voltage and keep a period of
time. The time interval when the output voltage of CO turns from “L” to “H” is the overcharge
release delay time.
3. Over-discharge Protection Test
Test circuit 2
3.1 Over-discharge threshold (VDET2) and Over-discharge release threshold (VREL2
)
Set V1=V2=V3=V4=V5=3.50V, make sure the output voltages of DO and CO pins are “H” level.
Decrease V5 gradually, monitor DO voltage and keep the condition not shorter than Tdet2, the
value of V5 when the output voltage of DO turns from “H” to “L” is the over-discharge threshold
voltage. Increase V5, the value of V5 when DO returns to “H” level again is the over-discharge
release threshold.
3.2 Over-discharge protection delay time and Over-discharge release delay time
(1) Set V1=V2=V3=V4=V5=3.50V, make sure the output voltages of DO and CO pins are “H” level.
Decrease V5 to 2.0V instantaneously, monitor DO voltage and keep a period of time. The time
interval when DO turns from “H” to “L” is the over-discharge protection delay time.
(2) Set V1=V2=V3=V4=3.50V, V5=2.0V, make sure CO is “H” level, DO is “L” level. Increase V5 to
3.5V instantaneously, monitor DO voltage and keep a period of time. The time interval when the
output voltage of DO turns from “L” to “H” is the overcharge release delay time.
Datasheet
WI-D06-J-0036 Rev.A/1
21 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
4. Discharge overcurrent and short circuit Protection Test
Test circuit 3
4.1 Discharge overcurrent1 and 2 threshold (VDET3, VDET4) and short circuit threshold (VSHORT
)
Set V1=V2=V3=V4=V5=3.5V, V6=0V, make sure the output voltages of DO and CO pins are “H”
level. Increase V6 gradually, monitor Do voltage and keep the condition for a period of time, the
value of V6 when the output voltage of Do turns from “H” to “L”, is the discharge overcurrent 1
threshold (VDET3). Decrease V6, the discharge overcurrent 1 protection will be released. VDET4 and
V
SHORT can also be tested by their protection time differences, but V6 has a larger change.
4.2 Discharge overcurrent protection delay time and release delay time
(1) Set V1=V2=V3=V4=V5=3.50V, V6=0V, make sure the output voltages of DO and CO pins are “H”.
Increase V6 to 0.2V instantaneously, monitor DO voltage and keep a period of time. The time
interval when the output voltage of DO turns from “H” to “L” is the discharge overcurrent 1
protection delay time.
(2) Set V1=V2=V3=V4=V5=3.50V, V6=0V, make sure the output voltages of DO and CO pins are “H”.
Increase V6 instantaneously with its value be larger, monitor DO voltage and keep a period of time.
The time interval when the output voltage of DO turns from “H” to “L” is the discharge overcurrent
2 protection delay time, make sure its value is less than the discharge overcurrent 1 protection
delay time, then the value of V6 at this time is the discharge overcurrent 2 threshold.
(3) Set V1=V2=V3=V4=V5=3.50V, V6=0V, make sure the voltages of DO and CO pins are “H”.
Increase V6 instantaneously with its value lager and larger, monitor DO voltage and keep a period
of time. The time interval when DO turns from “H” to “L” is the short circuit protection delay time,
make sure its value is less than the discharge overcurrent 2 protection delay time, and the value of
V6 at this time is the short circuit threshold.
(4) Set V1=V2=V3=V4=V5=3.50V, V6=0.2V, make sure the output voltage of DO pin and CO pin is “L”
and “H”. Decrease V6 to 0V instantaneously, monitor DO voltage and last a period of time. The
time interval when DO turns from “L” to “H” is the discharge overcurrent 1 release delay time, we
can test the release delay time of discharge overcurrent 2 and short circuit by using the same
method.
5. Charge overcurrent Protection Test
Test circuit 4
5.1 Charge overcurrent threshold
Set V1=V2=V3=V4=V5=3.50V, V7=0V, make sure the output voltages of DO and CO pins are “H”.
Increase V6 gradually, monitor CO voltage and keep a period of time. The value of V7 when the
output voltage of CO turns from “H” to “L” is the charge overcurrent threshold.
5.2 Charge overcurrent protection delay time
Set V1=V2=V3=V4=V5=3.50V, V7=0V, make sure the output voltages of DO and CO pins are “H”.
Increase V7 to 0.3V instantaneously, monitor the CO voltage and keep a period of time. The time
interval when the output voltage of CO pin turns from “H” to “L” is the charge overcurrent
protection delay time.
6. Cell Balance threshold Test
Test circuit 5
Set V1=V2=V3=V4=V5=3.50V, make sure the output voltage of BAL1 pin is 0V. Increase V1
Datasheet
WI-D06-J-0036 Rev.A/1
22 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
gradually and monitor the voltage of BAL1. The value of V1 when the output voltage of BAL1 pin
turns from “0” to “H” (the voltage of V1) is the cell balance threshold. The test method of other cells
balance is as same as the method of V1.
7. Output/Input Resistance Test
7.1 The output resistances of CO and DO
(1) The output resistance when the output voltages of CO and DO pins are both “H”.
Test circuit 6
Set V1=V2=V3=V4=V5=3.50V, V6=12.0V, turn off the switch K and make sure the output voltage
of CO pin is “H”. Measure the voltage VA of CO pin; turn on the switch K, decrease the voltage V6
gradually from 12V, monitor the value of IA, and note down the output voltage VB of CO pin when
the value of IA is 50uA, then the output resistance of CO is calculated as follows: RCOH = (VA -
VB)/50 (MΩ)
We can also test the output resistance RDOH of DO pin with using the same method.
(2) The output resistance when the output voltage of DO pin is “L”.
Test circuit 7
Set V1=V2=V3=V4=V5=2.00V, V8=0.00V, turn off the switch K and make sure the output voltage
of DO pin is “L”. Turn on the switch K, increase the voltage V8 gradually from 0V, monitor the value
of IA, note down the output voltage VDO of DO pin when the value of IA is 50uA, then the output
resistance of DO is calculated as follows: RDOL= VDO/50 (MΩ)
7.2 The output resistances of balance pins BAL1, BAL2, BAL3, BAL4, BAL5
Test circuit 8
(1) Set VBAL < V1 < VDET1, V2=V3=V4=V5=3.5V, turn on the switch K1 and turn off K2, K3, K4,
K5,decrease V9 from VBAL ,note down the value V_9, which is the value of V9 when the current is
50uA, then the output resistance when the cell balance turn on is calculated as follows:
RBAL1H=(V1-V_9)/50 (MΩ)；
(2) Set V1=V2=V3=V4=V5=3.50V, turn on the switch K1 and turn off K2, K3, K4, K5, increase V9 from
0V ,note down the value V_9, which is the value of V9 when the current is -50uA, then the output
resistance when the cell balance turn off is calculated as follows: RBAL1L=V_9/50 (MΩ)；
(3) Set VBAL < V2 < VDET1, V1=V3=V4=V5=3.5V, turn on the switch K2 and turn off K1, K3, K4,
K5,decrease V9 from (V1+VBAL) ,note down the value V_9, which is the value of V9 when the
current is 50uA, then the output resistance when the cell balance turn on is calculated as follows:
RBAL2H=(V1+V2-V_9)/50 (MΩ)；
(4) Set V1=V2=V3=V4=V5=3.50V, turn on the switch K2 and turn off K1, K3, K4, K5, increase V9 from
V1 ,note down the value V_9, which is the value of V9 when the current is -50uA, then the output
resistance when the cell balance turn off is calculated as follows: RBAL1L=(V_9-V1)/50 (MΩ)；
(5) Set VBAL < V3 < VDET1, V1=V2=V4=V5=3.5V, turn on the switch K3 and turn off K1, K2, K4,
K5,decrease V9 from (V1+V2+VBAL) ,note down the value V_9, which is the value of V9 when the
current is 50uA, then the output resistance when the cell balance turn on is calculated as follows:
RBAL2H=(V1+V2+V3-V_9)/50 (MΩ)；
(6) Set V1=V2=V3=V4=V5=3.50V, turn on the switch K3 and turn off K1, K2, K4, K5, increase V9 from
(V1 +V2),note down the value V_9, which is the value of V9 when the current is -50uA, then the
output resistance when the cell balance turn off is calculated as follows: RBAL1L=(V_9-V1-V2)/50
(MΩ)；
Datasheet
WI-D06-J-0036 Rev.A/1
23 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
(7) Set VBAL < V4 < VDET1, V1=V2=V4=V5=3.5V, turn on the switch K4 and turn off K1, K2, K3,
K5,decrease V9 from (V1+V2+V3+VBAL) ,note down the value V_9, which is the value of V9 when
the current is 50uA, then the output resistance when the cell balance turn on is calculated as
follows: RBAL2H=(V1+V2+V3+V4-V_9)/50 (MΩ)；
(8) Set V1=V2=V3=V4=V5=3.50V, turn on the switch K4 and turn off K1, K2, K3, K5, increase V9 from
(V1 +V2+V3),note down the value V_9, which is the value of V9 when the current is -50uA, then
the output resistance when the cell balance turn off is calculated as follows:
RBAL1L=(V_9-V1-V2-V3)/50 (MΩ)；
(9) Set VBAL < V5 < VDET1, V1=V2=V4=V5=3.5V, turn on the switch K5 and turn off K1, K2, K3,
K4,decrease V9 from (V1+V2+V3++V4VBAL) ,note down the value V_9, which is the value of V9
when the current is 50uA, then the output resistance when the cell balance turn on is calculated as
follows: RBAL2H=(V1+V2+V3+V4+V5-V_9)/50 (MΩ)；
(10) Set V1=V2=V3=V4=V5=3.50V, turn on the switch K5 and turn off K1, K2, K3, K4, increase V9
from (V1 +V2+V3+V4),note down the value V_9, which is the value of V9 when the current is
-50uA, then the output resistance when the cell balance turn off is calculated as follows:
RBAL1L=(V_9-V1-V2-V3-V4)/50 (MΩ)；
1MΩ
1MΩ
VCC
VC5
BALUP
DOIN
COIN
TOV
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
BAL5
VC4
V5
V4
V3
V2
V1
TOVD
TOC1
TOC2
NTC
BAL4
VC3
BAL3
BM3451
VC2
BAL2
TRH
VM
VC1
BAL1
GND
SET
CO
-
DO
A
BALDN
VIN
OCCT
Test Circuit 1
Test Circuit 2
1MΩ
1MΩ
VCC
BALUP
DOIN
COIN
TOV
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VC5
BAL5
VC4
V5
V4
V3
V2
V1
0.1μF
TOVD
TOC1
TOC2
NTC
BAL4
0.1μF
VC3
BAL3
BM3451
VC2
BAL2
TRH
VM
VC1
BAL1
GND
SET
CO
DO
BALDN
VIN
10MΩ
OCCT
V7
Test Circuit 3
Test Circuit 4
Datasheet
WI-D06-J-0036 Rev.A/1
24 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Test Circuit 5
Test Circuit 6
Test Circuit 7
Test Circuit 8
Datasheet
WI-D06-J-0036 Rev.A/1
25 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Package Information
TSSOP28
Datasheet
WI-D06-J-0036 Rev.A/1
26 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
TSSOP20
Datasheet
WI-D06-J-0036 Rev.A/1
27 /28
BYD Microelectronics Co., Ltd.
BM3451 Series
Restrictions on Product Use
The information contained herein is subject to change without notice.
BYD Microelectronics Co., Ltd. (short for BME) exerts the greatest possible effort to ensure high
quality and reliability. Nevertheless, semiconductor devices in general can malfunction or fail due to
their inherent electrical sensitivity and vulnerability to physical stress. It is the responsibility of the
buyer, when utilizing BME products, to comply with the standards of safety in making a safe design
for the entire system, including redundancy, fire-prevention measures, and malfunction prevention,
to prevent any accidents, fires, or community damage that may ensue. In developing your designs,
please ensure that BME products are used within specified operating ranges as set forth in the most
recent BME products specifications.
The BME products listed in this document are intended for usage in general electronics applications
(computer, personal equipment, office equipment, measuring equipment, industrial robotics,
domestic appliances, etc.). These BME products are neither intended nor warranted for usage in
equipment that requires extraordinarily high quality and/or reliability or a malfunction or failure of
which may cause loss of human life or bodily injury (“Unintended Usage”). Unintended Usage
include atomic energy control instruments, airplane or spaceship instruments, transportation
instruments, traffic signal instruments, combustion control instruments, medical instruments, all
types of safety devices, etc.. Unintended Usage of BME products listed in this document shall be
made at the customer’s own risk.
BME is not responsible for any problems caused by circuits or diagrams described herein whose
related industrial properties, patents, or other rights belong to third parties. The application circuit
examples explain typical applications of the products, and do not guarantee the success of any
specific mass-production design.
Datasheet
WI-D06-J-0036 Rev.A/1
28 /28
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SI9137LG
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SI9122E
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