bq20z80-V101
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SLUS625D–SEPTEMBER 2004–REVISED OCTOBER 2005
Safety Overcurrent Protection
The bq20z80 reports a safety-overcurrent condition for either charge (SBS.Current( ) = positive) or discharge
(SBS.Current( ) = negative). A fault is reported when SBS.Current( ) is ≥ the DF:SOC Chg or DF:SOC Dsg
threshold for a period ≥DF:SOC Chg Time or ≥ the DF:SOC Dsg Time. During the period between the time
when excessive current, in charge, is first detected and the expiration of DF:SOC Chg Time, SBS.PFAlert( )
[SOCC] is set. Between the time when excessive current, in discharge, is first detected and the expiration of
DF:SOC Dsg TimeSBS.PFAlert( ) [SOCC] is set.
The protection in discharge or charge can be independently configured or disabled. If either DF:Permanent Fail
Cfg [XSOCC, XSOCD] are set, the SAFE pin is driven low and the SAFE pin is driven high. Also, if DF:SOC Chg
Time or DF:SOC Dsg Time are set to 0, this feature is disabled for the respective current direction.
SIZE
(BYTES)
DEFAULT
VALUE
NAME
CLASS / SUBCLASS
FORMAT
VALID RANGE
UNITS
SOC Chg
SOC Dsg
0 to 30000
0 to 30000
0 to 30
10000
10000
2
mA
2nd Level Safety / Current (17)
Integer
SOC Chg Time
SOC Dsg Time
1
1
s
s
0 (4 typical)
0 (4 typical)
0 to 30
Safety Overtemperature Protection
The bq20z80 reports a safety overtemperature condition for either charge (SBS.Current( ) = positive) or
discharge (SBS.Current( ) = negative). A fault is reported when SBS.Temperature( ) ≥ DF:SOT Chg or DF:SOT
Dsg threshold for a period ≥ DF:SOT Chg Time or DF:SOT Dsg Time. During the period between the time when
excessive temperature, in charge, is first detected and the expiration of DF:SOT Chg Time, SBS.PFAlert( )
[SOTC] is set. Between the time when excessive temperature, in discharge, is first detected and the expiration of
DF:SOT Dsg Time, SBS.PFAlert( ) [SOTD] is set.
Either discharge or charge protection can be independently configured or disabled. If either DF:Permanent Fail
Cfg [XSOTC, XSOTD] is set, the SAFE pin is driven low and the SAFE pin is driven high. If DF:SOT Chg Time or
DF:SOT Dsg Time is set to 0, this feature is disabled for the respective current direction.
SIZE
(BYTES)
DEFAULT
VALUE
NAME
DESCRIPTION
FORMAT
VALID RANGE
UNITS
SOT Chg
SOT Chg Time
SOT Dsg
0 to 1200
0 to 30
2
1
2
1
0.1°C
650
s
0.1°C
s
0 (4 typical)
750
2nd Level Safety / Temperature (18)
Integer
0 to 1200
0 to 30
SOT Dsg Time
0 (4 typical)
The bq20z80 reports an open thermistor condition when SBS.Temperature( ) ≤ DF:Open Thermistor for a time
≥ DF:Open Time .
Between the time when excessive temperature is first detected and the expiration of DF:Open Time,
SBS.PFAlert( ) [OTS] is set. When DF:Open Time expires or is cleared then SBS.PFAlert( ) [OTS] is cleared
If DF:Permanent Fail Cfg [XOTS] is set, the SAFE pin is driven low and the SAFE pin is driven high. If DF:Open
Time is set to 0, this feature is disabled.
VALID
RANGE
SIZE
(BYTES)
DEFAULT
VALUE
NAME
CLASS / SUBCLASS
FORMAT
UNITS
Open Thermistor
Open Time
-1000 to 1200
0 to 30
2
1
0.1°C
–333
2nd Level Safety /
Temperature (18)
Signed Int
s
0 (4 typical)
22
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