BQ24180_1 Datasheet, PDF (14/41 Pages) Texas Instruments – Fully Integrated Switch-Mode One-Cell Li-Ion Charger with Full USB Compliance and Accessory Power Connection

bq24180
SLUSA02 A – FEBRUARY 2010 – REVISED FEBRUARY 2010
www.ti.com
DETAILED DESCRIPTION
The bq24180 is a highly integrated synchronous switch-mode charger featuring integrated MOSFETs and small
external components, targeted at extremely space-limited portable applications powered by 1-cell Li-Ion or
Li-polymer battery pack. For current limited power source, such as a USB host or hub, the high efficiency
converter is critical in fully utilizing the input power capacity and quickly charging the battery. Due to the high
efficiency in a wide range of the input voltage and battery voltage, the switching mode charger is a good choice
for high speed charging with less power loss and better thermal management.
The bq24180 has two operation modes: charge mode and high impedance mode. In charge mode, the bq24180
supports a precision Li-ion or Li-polymer charging system for single-cell applications. In high impedance mode,
the bq24180 stops charging and operates in a mode with very low current from IN and battery, to effectively
reduce the power consumption when the portable device in standby mode. Through proper control, bq24180
achieves the smooth transition among different operation modes.
Charge Mode Operation
Adapter Plug IN
Watchdog Timer Expired
and Not Active, no active
host communication
No
VUVLO < VIN < VOVP?
Yes
Good Adapter
No
connected?
Yes
Begin Safety Timer
Wait 2s
VHIGH<VIN<VOVP
No
Yes
Enable 50mA
precharge current
Timer 2x
STAT = 0
VBAT > 2V?
Yes
No
Enable 50mA
precharge current
STAT = 0
Begin DEFAULT
Mode Battery
Charge Cycle
Figure 25. Startup on Adapter Plug-In in DEFAULT Mode
14
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