Three_or_Four_Series_Cell_Li-Ion_Pack_Supervisor_Module
Features
Complete and compact lithium-ion pack supervisor
Provides overvoltage, undervoltage, and
overcurrent protection for three or four series
Li-Ion cells
Combines bq2058 with charge/discharge control
FETs
High side low on-resistance FETs
Designed for battery pack integration
Direct connection for series battery terminals
Measures 2.10 X 0.70 inches
Low standby and operating currents
General Description
The bq2158 provides a complete solution for the supervi-
sion of three or four series Li-Ion cells. Designed for bat-
tery pack integration, the bq2158 incorporates a bq2058
Pack Supervisor, two FETs, and all other components re-
quired to monitor overvoltage, undervoltage, and over-
c u r r e n t c o n d i t i o n s.
T h e b o a r d p r o v i d e s d i r e c t
connections for the negative and positive terminals of
each cell. See Figure 1. Please refer to the bq2058 data
sheet for specific information on the operation of the
bq2058.
Unitrode configures the bq2158 based on the informa-
tion in Table 1.
Pin Descriptions
B1P
Battery 1 positive input/pack positive
B1N
Battery 1 negative input
B2N
Battery 2 negative input
B3N
Battery 3 negative input
B4N
Battery 4 negative input
POS
Pack positive
NEG
Pack negative
1
Three or Four Series Cell
Li-Ion Pack Supervisor Module
bq2158
5/99 B
2
Customer Name: ___________________________________________________________________________
Contact: _________________________________________
Phone: ______________________________
Address: _________________________________________________________________________________
_________________________________________________________________________________
Sales Contact: ____________________________________
Phone: ______________________________
Number of series cells (3 or 4)
________________________________________
Overvoltage threshold (4.25, 4.30 or 4.35V)
________________________________________
Charge current (3.9A max.)
________________________________________
Discharge current (3.9A max.)
________________________________________
FAE approval: _____________________________________
Date: _______________________________
Table 1. bq2158 Module Configuration
bq2158
Operation
The bq2158 monitors each series element for under-
voltage, over-voltage, and over-current conditions. If a
cell falls below V
UV
for t
UVD
, the bq2158 enters into
sleep mode. The bq2158 wakes up and enables discharge
if a voltage, V
CD
higher than the battery voltage, is ap-
plied across POS and NEG. Charging is disabled if a cell
exceeds V
OV
for t
OVD
, and can resume when the cell falls
below the V
CE
threshold. The bq2158 turns the dis-
charge FET off if the steady state load current exceeds
I
OC
for t
OCD
and turns it back on if the load is removed.
3
FG2158cc.eps
B1P
NC
Load
or
Charger
Three-Cell Configuration
POS
NEG
B1N
B2N
B3N
B4N
B1P
Load
or
Charger
Four-Cell Configuration
POS
NEG
B1N
B2N
B3N
B4N
Note: B1P, B4N, POS, and NEG accomodate a #20 AWG stranded wire.
B1N, B2N, and B3N accomodate a #24 AWG stranded wire.
Figure 1. Module Connection Diagram
Number of Cells
On-board bq2058 Configuration
3 cells
BAT1N tied to BAT1P
NSEL = V
SS
4 cells
NSEL = V
CC
Table 2. Pin Connections
bq2158
4
bq2158 Schematic
bq2158
5
6X .055
0
.055
.915
NEG
POS
B4N
B3N
B2N
B1N
B1P
1.065
1.440
1.640
1.845
2.045
.700
Q3
Q4
Q1
Q2
U1
C8
TP1O
R8
C6
C9
C5
C7
C1
C3
C4
R7
R5
C2
R4
R3
C10
D1
D2
R9
R2
R1
R11
R10
R6
2.100
.031
.065
.068
LAYER 1
LAYER 2
bq2158 Board
bq2158
PDF 
ZIP