Si9730
Vishay Siliconix
Dual-Cell Lithium Ion Battery Control IC
FEATURES
D
D
D
D
D
D
Over-Charge Protection
Over-Discharge Protection
Short Circuit Current Limiting
Battery Open-Circuit Center Tap Protection
Cell Voltage Balancing
Undervoltage Lockout
D
D
D
D
D
D
Individual Cell Voltage Monitoring
Low Operating Current (30
mA)
and Shutdown Current (1
mA)
Internal N-Channel MOSFET Driver
High Noise Immunity
Accurate ("1.19%) Over-Charge Voltage Detection
Four Different Cell Types Covered
DESCRIPTION
The Si9730 monitors the charging and discharging of dual-cell
lithium-ion battery packs (carbon or coke chemistry) ensuring
that battery capacity is fully utilized while ensuring safe
operation.
The Si9730 provides protection against
overcharge, over-discharge, and short circuit conditions which
are hazardous to the battery and the environment.
Battery voltages of each individual cell are monitored at the
center-tap connection by an internal A/D converter through the
V
C
pin. If one or both of the cells is determined to be
overcharged, an internal cell balancing network
“bleeds”
off
current at 15
mA
until both cells are charged to the same
maximum level. Depending on the condition of each cell, the
Si9730 will switch two external source-connected n-channel
MOSFETs on or off to allow the cells to be charged or to
provide current to the load.
The Si9730 is available in an 8-pin SOIC package with an
operating temperature range of
−25
to 85°C. The Si9730 is
available in both standard and lead (Pb)-free packages.
FUNCTIONAL BLOCK DIAGRAM AND PIN CONFIGURATION
C
V
DD
Undervoltage
Lockout
Timer
C
DELAY
Time Out
CLK
+
V
C1
−
Cell Balancing
Network
V
C
A/D
Converter
OUT
Control
Logic
+
V
C2
−
Oscillator
1.2 V
REF
V
SS
S
OUT
V
SS
DCO
I
LIMIT
I
S
V
M
GS Generator
V
M
Document Number: 70658
S-40135—Rev. F, 16-Feb-04
www.vishay.com
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