Features
a174 Protects and individually moni-
tors two Li-Ion series cells for
overvoltage, undervoltage
a174 Monitors pack for overcurrent
a174 Designed for battery pack inte-
gration
a174 Minimal external components
a174 Drives external FET switches
a174 Selectable overvoltage (VOV)
thresholds
- Mask programmable by
Benchmarq
- Standard version–4.25V
a174 Supply current: 12µA typical
a174 Sleep current: 0.7µA typical
a174 16-pin 150-mil narrow SOIC
General Description
The bq2058T Lithium Ion Pack Su-
pervisor is designed to control the
charge and discharge cell voltage lim-
its for two lithium-ion (Li-Ion) series
cells, accommodating battery packs
containing series/parallel configura-
tions. The low operating current does
not overdischarge the cells during pe-
riods of storage and does not signifi-
cantly increase the system discharge
load. The bq2058T can be part of a
low-cost Li-Ion charge control system
within the battery pack.
The bq2058T controls two external
FETs to limit the charge and discharge
potentials. The bq2058T allows charg-
ing when each individual cell voltage is
below V
OV
(overvoltage limit). If the
voltage on any cell exceeds V
OV
for a
user-configurable delay period (t
OVD
),
the open-drain CHG pin goes to the
high-impedance state, shutting off
charge to the battery pack. This safety
feature prevents overcharge of any cell
within the battery pack. After an over-
voltage condition occurs, each cell must
fall below V
CE
(charge enable voltage)
for the bq2058T to re-enable charging.
The bq2058T protects batteries from
overdischarge. If the voltage on any
cell falls below V
UV
(undervoltage
limit) for a user-configurable delay pe-
riod (t
UVD
), the DSG output is driven
low, shutting off the battery discharge.
This safety feature prevents overdis-
charge of any cell within the battery
pack.
The bq2058T also stops discharge on
detection of an overcurrent condition,
such as a short circuit. If an overcur-
rent condition occurs for a user-
configurable delay period (t
OCD
), the
DSG output is driven low, disconnect-
ing the load from the pack. DSG re-
mains low until removal of the short
circuit or overcurrent condition.
1
bq2058T
Lithium Ion Pack Supervisor
For 2-Cell Packs
1
PN2058T1.eps
16-Pin Narrow SOIC
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
DSG
V
CC
UVD
OVD
OCD
V
CC
CSH
BAT
1P
CHG
CTL
V
SS
CSL
BAT
2N
BAT
2N
BAT
2N
BAT
1N
Pin Connections
July 1997
CHG Charge control output
CTL Pack disable input
V
SS
Low potential input
CSL Overcurrent sense low-side
input
BAT
2N
Battery 2 negative input
BAT
1N
Battery 1 negative input
DSG Discharge control output
UVD Undervoltage delay input
OVD Overvoltage delay input
OCD Overcurrent delay input
V
CC
High potential input
CSH Overcurrent sense high-side
input
BAT
1P
Battery 1 positive input
Pin Names