LP3921 Datasheet, PDF (20/41 Pages) National Semiconductor (TI) – Battery Charger Management and Regulator Unit with Integrated Boomer® Audio Amplifier

LP3921
SNVS580A – AUGUST 2008 – REVISED MAY 2013
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The charge mode may be programmed to USB mode when the charger input is applied and the battery voltage is
above 3.0V. This provides two programmable current levels of 100 mA and 450 mA for a USB sourced supply
input at CHG_IN. Table 9.
EOC
EOC is disabled by default and should be enabled when the system processor is awake and the system detects
that a battery is present.
PROGRAMMING INFORMATION
Table 10. Register Address 8h'10: CHGCNTL1
BIT
NAME
FUNCTION
2
En_EOC
Enables the End Of Charge current level threshold detection.
When set to '0' the EOC is disabled.
The End Of Charge current threshold default setting is at 0.1C. This EOC value is set relative to C the set full
rate constant current. This threshold can be set to 0.1C, 0.15C, 0.2C or 0.25C by changing the contents of the
PROG_EOC[1:0] register bits.
Table 11. Register Address 8h'12: CHGCNTL3
BIT
NAME
FUNCTION
2
Prog_EOC[0]
Set the End Of Charge Current.
3
Prog_EOC[1]
See Table 7.
TERMINATION AND RESTART
The termination and restart voltage levels are determined by the data in the VTERM[1:0] and PROG_VSTRT[1:0]
bits in the control register. The restart voltage is programmed relative to the selected termination voltage.
The Termination voltages available are 4.1V, 4.2V (default), 4.3V, and 4.4V.
The Restart voltages are determined relative to the termination voltage level and may be set to 50 mV, 100 mV,
150 mV (default), and 200 mV below the set termination voltage level.
Table 12. Register Address 8h'12: CHGCNTL3
BIT
NAME
FUNCTION
4
VTERM[0]
Set the charging termination voltage.
5
VTERM[1]
See Table 6.
0
VRSTR[0]
Set the charging restart voltage. See Table 8.
1
VRSTR[1]
20
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