LP3913 Datasheet, PDF (40/70 Pages) Texas Instruments – Power Management IC for Flash Memory-Based Portable Media Players

LP3913
SNVS489I – NOVEMBER 2006 – REVISED SEPTEMBER 2013
The Safety timer resets and starts counting from zero upon the following events:
1. Power ON (through connecting valid power to either USBPWR or CHGN_IN pins).
2. Interchanging USBPWR and CHG_IN sources
3. The voltage of a charged battery drops below the restart value and the charger is enabled
4. Disabling and re-enabling of the charger by toggling bit D1 of the Charge Control Register
5. Emerging from Thermal Shutdown
6. Emerging from a battery temperature out-of-range and the charger is enabled
7. Emerging from USB suspend mode when charging with USB power
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Charging Maintenance
When a fully charged battery is being loaded by the system while the external power is present and while bit D1
in the charge control register is set to a 1 (Charge enable) then the charging will restart when the battery voltage
drops below the charging restart threshold. The value of the threshold depends on the termination voltage
according to the following table:
Vterm
4.1V
4.2V
4.38V
Charging restart voltage
3.9V
4.0V
4.2V
CHSPV Register (02)h Charger Supervisor Register
Access
Data
D7–6
Read only
Reserved
D5
r/w
LED Current
0: 5 mA
1: 10 mA
D4
r/w
LED ENABLE
0: Disabled
1:Enabled
D3
r/w
Battery
temperature
range
0: 0°C–50°C
1: 0°C–45°C
Reset
n/a
1
1
0
D2–0
Charger status
Stat2
0
0
0
Stat1
0
0
1
0
1
1
0
1
0
1
1
1
1
2’b000
Stat0
0
1
0
1
0
1
0
1
Charger is off
Prequalification
Constant current
charging
Constant voltage
charging
Error
Charge cycle
complete
Safety Timer
Expired
EOC / Top-off
Power Routing
The LP3913 power can originate from three different sources: Adapter power, USB power or battery power. The
objective of the power routing is to be able to:
• Operate the portable system from external power regardless of the battery voltage.
• Operate the portable system from USBPWR when the battery exceeds the Full Rate Qualification Threshold
voltage (Vfullrate).
• Concurrently charging and operating the system when external power is present
• Seamless selection of Adapter or USB power as the primary external power source
Power Routing supports 4 modes:
1. A regulated external adapter power is present and concurrently supplies the system power and the battery
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