BQ77PL157A4225 Datasheet, PDF (1/14 Pages) Texas Instruments – Voltage Protection for 3 to 6 Series Cell Lithium-Ion/Polymer Batteries

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bq77PL157A4225
SLUSA00 – MARCH 2010
Voltage Protection for 3 to 6 Series Cell Lithium-Ion/Polymer Batteries
Check for Samples: bq77PL157A4225
FEATURES
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• Single IC Li-Ion Protection for 3 to 6 Series
Cells
• Stackable to Protect up to 18 Series Cells
• Programmable Detection Time Delay
• Low Power Consumption
– Typical 2 µA to 2.5 µA Normal Mode
• Fixed Overvoltage Thresholds Available From
3.75 V to 4.35 V in 25-mV Steps
• Highly Accurate: ±20 mV MAX, T_A = 0°C to
50°C
• Output Activation for Low Side FET
(Contact TI for Alternate Output Options:
High/Low-side Fuse or FET.)
• Protected Output, Power, and Ground Pins for
Added Safety and Reliability
• Permanent or Recoverable Fault Options
• 16-pin Small Outline Package
APPLICATIONS
• Primary or Secondary Level Voltage Protection
for Li-Ion Battery Packs for Use in:
– Power Tools
– UPS Systems
– E-Bikes, Scooters and Small Mobility
Vehicles
– Medical Devices, Test Equipment, and
Industrial Products
DESCRIPTION
The bq77PL157 is a stackable overvoltage protection
device for 3, 4, 5 or 6 series cell Li-Ion battery packs.
This device incorporates a precise and accurate
overvoltage detection circuit with preconfigured
threshold limits. Additional features include the ability
to stack multiple parts to monitor up to 18 series
cells. Preconfigured options include latched
(permanent) or recoverable fault output, as well as
specific voltage threshold limits selectable in 25 mV
steps.
FUNCTION
Each series cell in a Li-Ion battery pack is compared
to an internal reference voltage. If one cell reaches
an overvoltage condition, the protection sequence
begins. The bq77PL157 starts charging an external
capacitor through the CD pin. When the CD pin
voltage reaches 1.2 V, the OUT pin changes state
and the LVO pin becomes active.
If multiple bq77PL157 devices are stacked, the LVIN
pin of the next-lower device receives the LVO pin
from the above device and similarly starts a
shortened delay timer before activating its OUT pin.
(No additional isolation or level-shift circuitry is
required.) The lowest bq77PL157 in the string is used
to activate a power MOSFET located in the low side
of the power path.
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2010, Texas Instruments Incorporated