BQ2970 Datasheet, PDF (20/31 Pages) Texas Instruments – Cost-Effective Voltage and Current Protection Integrated Circuit

bq2970, bq2971, bq2972, bq2973
SLUSBU9C – MARCH 2014 – REVISED MARCH 2016
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10 Applications and Implementation
10.1 Application Information
The bq2970 devices are a family of primary protectors used for protection of the battery pack in the application.
The application drives two low-side NMOS FETs that are controlled to provide energy to the system loads or
interrupt the power in the event of a fault condition.
10.2 Typical Application
PACK +
NC
COUT
DOUT
2. 2 k
V–
BAT
VSS
330
CELLP
CELLN
PACK–
S
D
S
CHG
DSG
NOTE: The 5-M resistor for an external gate-source is optional.
Figure 26. Typical Application Schematic, bq2970
10.2.1 Design Requirements
For this design example, use the parameters listed in Table 2.
Table 2. Design Parameters
DESIGN PARAMETER
Input voltage range
Maximum operating discharge current
Maximum Charge Current for battery pack
Overvoltage Protection (OVP)
Overvoltage detection delay timer
Overvoltage Protection (OVP) release voltage
Undervoltage Protection (UVP)
Undervoltage detection delay timer
Undervoltage Protection (UVP) release voltage
Charge Overcurrent detection (OCC) voltage
Charge Overcurrent Detection (OCC) delay timer
Discharge Overcurrent Detection (OCD) voltage
Discharge Overcurrent Detection (OCD) delay timer
Load Short Circuit Detection SCC) voltage, BAT to –V ≤ threshold
Load Short Circuit Detection (SCC) delay timer
Load Short Circuit release voltage, BAT to –V ≥ Threshold
EXAMPLE VALUE at T_A = 25°C
4.5 V to 7 V
7A
4.5 A
4.275 V
1.2 s
4.175 V
2.8 V
150 ms
2.9 V
–70 mV
9 ms
100 mV
18 ms
500 mV
250 µs
1V
20
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