TI BQ2158TB-

Preliminary
bq2158T
Two Series Cell
Li-Ion Pack Supervisor Module
Features
ä
Complete and compact lithium-ion pack supervisor
ä
Provides overvoltage, undervoltage, and
overcurrent protection for two series Li-Ion cells
ä
Combines bq2058T with charge/discharge control
FETs
ä
Low side low on-resistance FETs
ä
Designed for battery pack integration
ä
–
Direct connection for series battery terminals
–
Measures 1.70 X 0.70 inches
Low standby and operating currents
General Description
Pin Descriptions
The bq2158T provides a complete solution for the supervision of two series Li-Ion cells. Designed for battery
pack integration, the bq2158T incorporates a bq2058T
Pack Supervisor, two FETs, and all other components required to monitor overvoltage, undervoltage, and overcu rre n t c o nd i ti o ns. T he bo a r d p r o v id es d ir ec t
connections for the negative and positive terminals of
each cell. See Figure 1. Please refer to the bq2058T
data sheet for specific information on the operation of
the bq2058T.
Unitrode configures the bq2158T based on the information in Table 1.
4/99
1
B1P
Battery 1 positive input
B1N
Battery 1 negative input
B2N
Battery 2 negative input
POS
Pack positive
NEG
Pack negative
bq2158T Preliminary
Table 1. bq2158T Module Configuration
Customer Name: ___________________________________________________________________________
Contact: _________________________________________
Phone: ______________________________
Address: _________________________________________________________________________________
_________________________________________________________________________________
Sales Contact: ____________________________________
Phone: ______________________________
Overvoltage threshold (4.25V)
________________________________________
Charge current (3.8A max.)
________________________________________
Discharge current (3.8A max.)
________________________________________
FAE approval: ____________________________________
2
Date:________________________________
Preliminary bq2158T
POS
B1P
Load
or
Charger
B1N
B2N
NEG
Note: B1P, B2N, POS, and NEG accomodate a #20 AWG stranded wire.
B1N accomodates a #24 AWG stranded wire.
FG2158Tcd.eps
Figure 1. Module Connection Diagram
Operation
The bq2158T monitors each series element for undervoltage, over-voltage, and over-current conditions. If a
cell falls below VUV for tUVD, the bq2158T enters into
sleep mode. The bq2158T wakes up and enables discharge if a voltage, VCD higher than the battery voltage,
is applied across POS and NEG. Charging is disabled if
a cell exceeds VOV for tOVD, and can resume when the
cell falls below the VCE threshold. The bq2158T turns
the discharge FET off if the steady state load current exceeds IOC for tOCD and turns it back on if the load is removed.
3
bq2158T Preliminary
bq2158T Schematic
bq2158t-b6/18/98
4
Preliminary bq2158T
bq2158T Board
R5
R3
C4
R7
.355
B2N
2x .055
.000
3x 1.645
.000
2x .055
TP1
D1
C7
R2
R4
Q3
NEG
Q2
C2
C5
C6
U1
C1
.700
2x .645
B1P
B1N
C3
Q1
POS
R6
C8
R1
1.700
.068
.031
LAYER 1
LAYER 2
5
bq2158T Preliminary
Absolute Maximum Ratings
Symbol
Parameter
Value
Unit
Conditions
VOP
Supply voltage (B1P to B2N)
12
V
DC
VTR
Maximum transient voltage (B1P to B2N)
32
V
Maximum duration =
1.5µs
VCHG
Charging voltage (POS to NEG)
12
V
ICHG
Continuous charge/discharge current
3.8
A
TOPR
Operating temperature
-30 to +70
°C
TSTG
Storage temperature
-55 to +125
°C
Note:
VOP > 4V
TA = 25°C
Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional operation
should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Exposure to conditions beyond the operational limits for extended periods of time may affect device reliability.
DC Electrical Characteristics (TA = TOPR)
Symbol
Parameter
Minimum
Typical
Maximum
Unit
4.0
-
12
V
Conditions/Notes
VOP
Operating voltage, B1P to
B2N
ICCA
Operating current
-
26
43
µA
ICCS
Sleep current
-
0.7
1.5
µA
No load across POS and
NEG
RON
On resistance, B2N to NEG
-
-
100
mΩ
TA = 25°C
VOP = 4.5V
6
Preliminary bq2158T
DC Thresholds (TA = TOPR)
Symbol
Parameter
Value
Tolerance
Unit
VOV
Overvoltage threshold
4.25
± 50mV
V
VCE
Charge enable voltage
VOV - 100mV
± 50mV
V
VUV
Undervoltage limit
2.25
± 100mV
V
IOC
Overcurrent limit
Notes
3.3
A
TA = 25°C
3
A
TA = 60°C
TA = 30°C
tUVD
Undervoltage delay
950
±50%
ms
VCD
Charge detect threshold
70
-60, +80
mV
tOVD
Overvoltage delay
950
±50%
ms
TA = 30°C
tOCD
Overcurrent delay
12
±60%
ms
TA = 30°C
Ordering Information
bq2158T
B —
Customer Code:
Blank = Sample or Pre-production1
XXX = Customer-specific; assigned by Unitrode2
Package Option:
B = Board-level product
Device:
Two-Series Cell Li-Ion Supervisor Module
Notes:
1. Requires configuration sheet (Table 1)
2. Example production part number: bq2158TB-001
7
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