AAT2550 Datasheet, PDF (16/35 Pages) Advanced Analogic Technologies – Total Power Solution for Portable Applications

AAT2550
Total Power Solution for Portable Applications
System Operation Flow Chart
OOuuttppuutt
AADDPPPP
PPoowweer _r OOnn
RReesseett
ADP
Yes Voltage
Test
ADP > V_ADPP
No
AADDPP
LLoooopp
ADP
Power Select
Yes
UVLO
Yes
V_{P > VUVLO}
No
Enable
SSwwiittcchh
OOnn
No
SSlleeeepp
MMooddee
Fault
Conditions Monitor ^Yes
OV, OT
No
Timing
SShhuuttdDoowwnn
MMooddee
Expire
Yes
No
Recharge Test
V_RCH > V_BAT
Battery
Temp. Monitor
V_TS1 <TS<V_TS2
Yes
No
BBaatttteerryy
TTeemmpp..FFaauultlt
CChhaarrggee
SSaaffeettyy
TTimimeerr
Preconditioning Test ^Yes
V_MIN > V_BAT
LLoowwCCuurrrreenntt
CCoonnddititioionniningg
CChhaarrggee
Set
ThTehrmeraml ^aLloop
LooEpnEanbaleble
No
Device Temp. Monitor
T_J > 110°C
Yes
TThheerrmmaal _l LLoooopp
CCuurrrreenntt
RReedduuccttioionnininAADDPP
CChhaarrggininggMMooddee
No
Current Phase Test ^Yes
V_CH > V_BAT
CCuurrrreenntt
CChhaarrgginingg
MMooddee
No
Voltage Phase Test ^Yes
I_BAT> I_MIN
No
CChhaarrggee
CCoommppleletteedd
VVooltltaaggee
CChhaarrgginingg
MMooddee
Current Limit and Over-Temperature
Protection
For overload conditions, the peak input current is
limited. To minimize power dissipation and stresses
under current limit and short-circuit conditions,
switching is terminated after entering current limit
for a series of pulses. Switching is terminated for
seven consecutive clock cycles after a current limit
has been sensed for a series of four consecutive
clock cycles.
Thermal protection completely disables switching
when internal dissipation becomes excessive. The
junction over-temperature threshold is 140°C with
15°C of hysteresis. Once an over-temperature or
over-current fault conditions is removed, the output
voltage automatically recovers.
Under-Voltage Lockout
The under-voltage lockout circuit prevents the
device from improper operation at low input volt-
ages. Internal bias of all circuits is controlled via the
VIN input. Under-voltage lockout (UVLO) guaran-
tees sufficient V_IN bias and proper operation of all
internal circuitry prior to activation.
16
2550.2006.07.1.0