LP3921 Datasheet, PDF (23/41 Pages) National Semiconductor (TI) – Battery Charger Management and Regulator Unit with Integrated Boomer® Audio Amplifier

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Prequalification to Fast
Charge transition
1.0 C
V_TERM
V_RSTRT
3.0V
Transition to Constant
Voltage-mode
Charging current
LP3921
SNVS580A – AUGUST 2008 – REVISED MAY 2013
Maintenance charging
starts
Charging current
50 mA
EOC
Time
Figure 7. Charge Cycle Diagram
Further Charger Register Information
CHARGER CONTROL REGISTER 1
Table 14. Register Address 8h'10: CHGCNTL1
BIT
NAME
FUNCTION (if bit = '1')
7
USB_MODE
Sets the Current Level in USB mode.
_EN
6
CHG_MODE
Forces the charger into USB mode when active high.
_EN
If low, charger is in normal charge mode.
5
FORCE
Forces an EOC event.
_EOC
4
TOUT_
Doubles the timeout delays for all timeout signals.
Doubling
3
EN_Tout
Enables the timeout counters. When set to '0' the timeout counters
are disabled.
2
EN_EOC
Enables the End of Charge current level threshold detection.
When set to '0' the functions are disabled.
1
Set_
Forces the charger into LDO mode.
LDOmode
0
EN_CHG
Charger enable.
Table 15. Register Address 8h'13: CHGSTATUS1
BIT
NAME
FUNCTION (if bit = '1')
7
BAT_OVER
Is set when battery voltage exceeds 4.7V.
_OUT
6
CHGIN_
Is set when a valid input voltage is detected at CHG_IN pin.
OK_Out
5
EOC
Is set when the charging current decreases below the
programmed End Of Charge level.
4
Tout_
Set after timeout on full rate charge.
Fullrate
3
Tout_
Set after timeout for precharge mode.
Precharge
2
LDO_Mode
This bit is disabled in LP3921. Contact NSC sales if this option is
required as in LP3918–L.
1
Fullrate
Set when the charger is in CC/CV mode.
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