Datasheet

USB100
USB 500
V
REF -
ILIM
USB- susp
ShortDetect
V
IPRECHG
V
I CHG
ShortDetect
I
BAT(SC
)
T
J(REG )
T
J
V
DPPM
V
SYS
V
BAT(REG
)
V
BAT(SC)
V
O(REG)
V
O(SC1
)
OUT -SC1
t
DG L (T ER M )
BAT -SC
V
REF
-
ITERM
Q1
Q2
t
D G L1(L O W V
)
t
D G L(R C H)
V
LOWV
V
RCH
I
NTC
V
HOT
V
COL
D
t
DGL(NO -
IN )
t
DGL(PGOOD
)
t
BLK(OVP )
V
BAT
+V
AC -DT
V
UVLO
V
OVP
V
AC
Dynamical
ly
Controlled
Oscillator
V
IPRECHG
V
ICHG
V
ISET
~100mV
Fast - Charge
Timer
Pre -Charge
Timer
Halt
timers
Timer
fault
EN2
AC
TS
SYS
BAT
ISET
ChargeControl
I
BAT (DET)
V
IN -LOW
V
BAT
OUT-SC2
Reset
timers
t
DGL(T
S
)
Timers
disabled
I
BIAS -
ITERM
V
OUT
Supplement
ITERM -
floating
t
DGL(SC2)
250mV
40mV
V
DIS(TS)
~3V
t
D G L2(L O W V
)
<I_TERM0>
<I_TERM1>
<IN_CUR_LIM>
<USB_SUSP>
<CH_VLT0>
<CH_VLT1>
< I_PR_CH0>
< I_PR_CH1>
< >
< >
<V_ DPM>
<TERM_DIS>
<USB_SUSP>
<CH_EN>
<DYN_TMR>
<TH_LOOP>
<SFTY_TMR_0>
<SFTY_TMR1>
<PR_ CH_TMR>
<TMR_F>
<VOUT_0>
<VOUT_1>
<TS_ON>
<TS_HOT>
<TS_COLD>
<E_I_TS>
<CH_DONE>
<PGOOD>
T3L : TD
T3L:/GHG
T3L:/PGOOD
T3L:ITERM
T3L:/CE
I_CH_SCL0
I_CH_SCL1
TPS65720
TPS65721
www.ti.com SLVS979 –OCTOBER 2009
Figure 23. Charger Block Diagram
BATTERY CHARGING
When <CH_EN>=1, battery charging begins. First, the device checks for a short circuit on the BAT pin by
sourcing I
BAT(SC)
to the battery and monitoring the voltage. When the BAT voltage exceeds V
BAT(SC)
, the battery
charging continues. The battery is charged in three phases: conditioning precharge, constant-current fast charge
(current regulation) and a constant-voltage tapering (voltage regulation). In all charge phases, an internal control
loop monitors the IC junction temperature and reduces the charge current if an internal temperature threshold is
exceeded.
Figure 24 shows what happens in each of the three phases:
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