BQ2058T Datasheet, PDF (1/18 Pages) Texas Instruments – Lithium Ion Pack Supervisor For 2-Cell Packs

bq2058T
Lithium Ion Pack Supervisor
For 2-Cell Packs
Features
® Protects and individually moni-
tors two Li-Ion series cells for
overvoltage, undervoltage
® Monitors pack for overcurrent
® Designed for battery pack inte-
gration
® Minimal external components
® Drives external FET switches
® Selectable overvoltage (VOV)
thresholds
- Mask programmable by
Benchmarq
- Standard version–4.25V
® Supply current: 12µA typical
® Sleep current: 0.7µA typical
® 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 VOV (overvoltage limit). If the
voltage on any cell exceeds VOV for a
user-configurable delay period (tOVD),
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 VUV (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 (tOCD), 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.
Pin Connections
CHG 1
CTL 2
VSS
3
CSL 4
BAT2N
5
BAT2N
6
BAT2N
7
BAT1N
8
16
DSG
15
VCC
14
UVD
13
OVD
12
OCD
11
VCC
10
CSH
9
BAT1P
16-Pin Narrow SOIC
PN2058T1.eps
July 1997
Pin Names
CHG
CTL
V_SS
CSL
BAT_2N
BAT_1N
Charge control output
Pack disable input
Low potential input
Overcurrent sense low-side
input
Battery 2 negative input
Battery 1 negative input
DSG
UVD
OVD
OCD
V_CC
CSH
BAT1P
Discharge control output
Undervoltage delay input
Overvoltage delay input
Overcurrent delay input
High potential input
Overcurrent sense high-side
input
Battery 1 positive input
1