BQ2961_17 Datasheet, PDF (13/33 Pages) Texas Instruments – Overvoltage Protection for 2-Series, 3-Series, and 4-Series Cell Li-Ion Batteries with Regulated Output Supply

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bq2961, bq2962
SLUSBU5D – NOVEMBER 2013 – REVISED JANUARY 2017
Feature Description (continued)
The REG output has protection for overcurrent, using a current limit protection circuit, and also detects and
protects for excessive power dissipation due to short circuit of the external load. This pin requires a ceramic 1-µF
capacitor connection to VSS for improved stability, noise immunity, and ESD performance of the supply output.
This capacitor must be placed close to the REG and VSS pins for connection.
8.3.1.5 Regulated Supply Output Enable, REG_EN (bq2960 Only)
This terminal is a high voltage input drain to enable and disable the regulated supply output, REG terminal.
When the VREG_EN > V_IH, the REG terminal output is enabled including the cell undervoltage detection function
to self-disable the regulated supply. When the VREG_EN < V_IL, the REG terminal output, the cell undervoltage
detection and the regulated supply self-disable functions are disabled.
To keep the REG output enabled at all times, the recommendation is to connect the REG_EN to the V1
termination. There is a 6-V clamp to protect the REG_EN terminal from a high voltage input. By connecting
REG_EN to V1, the clamp circuit is not active.
When the REG output is enabled, VREG_EN > V_IH, the REG output can be self-disabled if any of the cell
voltages are < V_UVREG. The self-disable function is used to reduce power consumption when the battery pack is
deeply depleted.
8.3.2 Overvoltage Sensing for OUT
In the bq296xxx device, each cell is monitored independently. Overvoltage is detected by comparing the actual
cell voltage to a protection voltage reference, V_OV. If any cell voltage exceeds the programmed OV value, an
internal timer circuit is activated. This timer circuit causes a factory pre-programmed fixed delay before the OUT
terminal goes from inactive to active state.
VOV
VOV - VHYS
OUT (V)
tDELAY
Figure 11. Timing for Overvoltage Sensing for OUT
8.3.3 Regulated Output Voltage and REG_EN Pin
For bq2960 and bq2961, there are three factory-preprogrammed options for the regulated output voltage, 3.3 V,
2.5 V, and 1.8 V. For bq2962, the regulated output voltage options are 3.3 V, 3.15 V, and 3.0 V. bq2962xy can
potentially provide other regulated voltage output between 3.3 V to 3.0 V, contact Texas Instruments for detail.
At power up, the regulated output is on by default. If any cell voltage is below V_UVREG at device power up, the
regulated output will remain on until the t_{UV_DELAY} time has passed, the regulated out turns off after the delay
time.
During discharge, if any cell voltage falls below the V_UVREG threshold for t_{UV_DELAY} time, the regulated output is
self-disabled. The regulated output turns on again when all the cell voltages are above V_UVREG + V_UVHYS.
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Product Folder Links: bq2961 bq2962
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