bq20z80-V101
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SLUS625D–SEPTEMBER 2004–REVISED OCTOBER 2005
The bq20z80 sets SBS.ChargingStatus( ) [PCMTO] if the Pre-Charge Timer ≥ DF:PC-MTO, and if DF:Charge
Fault Cfg [XPCMTO] is set, then the CHG FET is turned off, and the ZVCHG FET is turned off if DF:Operation
Cfg A [ZVCHG1, ZVCHG0] are set appropriately. Also, SBS.ChargingCurrent( ) and SBS.ChargingVoltage( ) are
set to 0, and SBS.BatteryStatus( ) [TCA] is set. If DF:PC-MTO is programmed to 0, this feature is completely
disabled.
To recover from this mode, SBS.Current( ) must be ≥ (-) DF:Dsg Current Threshold, or if DF:Operation Cfg B
[NR] = 0 AND PRES transitions from low-to-high-to-low. On recovery, the SBS.ChargingCurrent( ),
SBS.ChargingVoltage( ) and the CHG and ZVCHG FETs are returned to the previous state in accordance with
the charging algorithm, SBS.BatteryStatus( ) [TCA] and SBS.ChargingStatus( ) [PCMTO] are cleared.
SIZE
(BYTES)
DEFAULT
VALUE
NAME
CLASS / SUBCLASS
FORMAT
VALID RANGE
UNITS
PC-MTO
Charging Control / Charging Faults (38)
Integer
0 to 65,535
2
s
3600
POWER MODE
The bq20z80 has several power modes. During these modes, the bq20z80 modifies its operation to minimize
power consumption from the battery.
During normal operation, the bq20z80 takes ADC.Current, ADC.Voltage, and ADC.Temperature measurements,
performs calculations, updates SBS data, and makes protection and status decisions at one-second intervals.
Between these periods of activity, the bq20z80 is in a reduced power state.
PRES is detected during the measurement period, where the PU pin is pulled high, the PRES input state is read,
and PU is released. If PRES is high, SBS.OperationStatus( ) [PRES] is cleared. If PRES is low,
SBS.OperationStatus( ) [PRES] is set indicating the system is present (the battery is inserted).
If DF:Operation Cfg B [NR] is set, the PRES input can be left floating as it is not monitored.
Normal Mode Discharge Fault – Current
The bq20z80 reports a Normal Mode Discharge fault due to Current by setting SBS.OperationStatus( ) [XDSGI]
any SBS.SafetyStatus(
) [OCD, OCD2, AOCD, ASCD] is set. Also, SBS.ChargingCurrent( ) and
SBS.BatteryStatus( ) [TCA] are changed according to SBS.SafetyStatus( ) flag.
When all of SBS.SafetyStatus( ) [OCD, OCD2, AOCD, ASCD] are cleared, SBS.BatteryStatus( ) [TDA] and
SBS.OperationStatus( ) [XDSGI] are also cleared.
Sleep Mode
In Sleep mode, the bq20z80 measures ADC.Voltage and ADC.Temperature every DF:Sleep Voltage Time
interval, and ADC.Current is measured at intervals of DF:Sleep Current Time. At each interval, the bq20z80
performs calculations, updates SBS data and makes protection and status decisions. Between these periods of
activity, the bq20z80 is in a reduced-power state.
The bq20z80 enters Sleep mode when the following conditions exist.
•
•
•
SBS.Current( ) in charge or discharge is ≤ DF:Sleep Current, AND SMBus is Low for DF:Bus Low Time,
AND DF:Operation Cfg A [SLEEP] is set
OR
SBS.Current( ) is ≤ DF:Sleep Current in discharge, AND SBS.ManufacturerAccess( ) Sleep command is
received, AND DF:Operation Cfg A [SLEEP] is set.
AND
If DF:Operation Cfg B [NR] is cleared, the PRES input must also be high, SBS.OperationStatus( ) [PRES] =
0, for the bq20z80 to enter sleep.
Entry to Sleep mode is blocked if any of SBS.SafetyStatus( ) [OCD, OCC, OCD2, OCC2, PF, AOCD, ASCC,
ASCD] are set, or if any protection-feature recovery timers are active and have not expired, or if DF:Sleep
Voltage Time =0 or DF:Sleep Current Time = 0, sleep mode is not entered, and the bq20z80 remains in Normal
mode.
64
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