1FEATURES

? Single IC Li-Ion Protection for 3-Series 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 4.225 V Overvoltage Threshold

? Highly Accurate: ±20-mV MAX, TA = 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.

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.