Thermistor Monitoring with Charger Shutdown
Figure 5a. Charger State Diagram (Thermistor Monitoring with Charger Shutdown)
MAX20335
PMIC with Ultra-Low I
Q
Voltage Regulators and
Battery Chargers for Small Lithium Ion Systems
www.maximintegrated.com
Maxim Integrated
│
36
MAINTAIN
CHARGE DONE
ChgStat = 110
LED = OFF
I
CHG
= 0
CHARGER OFF
ChgStat = 000
LED = OFF
I
CHG
= 0
PREQUAL
ChgStat = 010
LED = ON
I
CHG
= I
PCHG
FAST
CHARGE
(CONSTANT CURRENT)
ChgStat = 011
I
CHG
= I
FCHG
**
LED = ON
FAST
CHARGE
(CONSTANT VOLTAGE)
ChgStat = 100
LED = ON
I
CHG
= I
FCHG
MAINTAIN
CHARGE
ChgStat = 101
LED = ON
I
CHG
< I
CHG_DONE
CHARGE SUSPEND
ChgStat = 001
LED = 1.5s PERIOD
I
CHG
= 0
FAULT
ChgStat = 111
LED = 0.15s PERIOD
I
CHG
= 0
PREQUAL SUSPEND
ChgStat = 001
LED = 1.5s PERIOD
I
CHG
= 0
FAST
CHARGE
CC SUSPEND
ChgStat = 001
LED = 1.5s PERIOD
I
CHG
= 0
FAST
CHARGE
CV SUSPEND
ChgStat = 001
LED = 1.5s PERIOD
I
CHG
= 0
ChgEn = 1,
V
SYS
> V
SYS_LIM
RISE
V
BAT
> V
BAT_PChg
RESET CHARGE TIMER
V
BAT
< V
BAT_PChg
RESET CHARGE TIMER
VOLTAGE MODE = 1* AND
V
SYS
> V
SYS_LIM
RISE
(VOLTAGE MODE = 0*
AND V
SYS
> V
SYS_LIM
RISE)
OR V
BAT
< V
BAT_PChg
RECOVER FROM FAULT
RESET CHARGE TIMER
T1 < T < T3
T < T1 or T > T3
T1<T<T3
T<T1 or T>T3
T1<T<T3
T<T1 or T>T3
RESET CHARGE TIMER
T1 < T < T3
T < T1 or T > T3
T < T1 or T > T3
I
CHG
> I
CHG_DONE
ChgAutoStp = 0"
RESET CHARGE TIMER
I
CHG
< I
CHG_DONE
AND
V
SYS
> V
SYS_LIM
RISE
AND
T
DIE
< T
CHG_LIM
RESET CHARGE TIMER
t
CHG_TIMER
> t
MTCHG
AND
ChgAutoStp = 1
V
BAT
< V
BATREG
– V
BATRECHG
AND ChgAutoReSta = 1
AND V
SYS
> V
SYS_LIM
RISE
RESET CHARGE TIMER
PAUSE
CHARGE
TIMER
PAUSE
CHARGE
TIMER
t
CHG_TIMER
> t
PCHG
t
CHG_TIMER
> t
FCHG
T
DIE
< T
BUS_LIM
OR V
BAT
> V
SYS
OR ChgEn = 0
FROM ANY STATE
NOTES:
* VOLTAGE MODE IS AN INTERNAL SIGNAL
** CHARGE TIMER IS SLOWED BY 50% IF I
CHG
< I
FCHG
/ 2 AND PAUSED IF I
CHG
< I
FCHG
/5 ONLY IN FAST CHARGE CONSTANT CURRENT STATE
t
MTCHG
PAUSE
CHARGE
TIMER