Step-Up Converter
for Handheld Applications
UVLO, EXCESSIVE
TEMPERATURE,
OR SHORT CIRCUIT
FROM ANY STATE
TRUE SHUTDOWN
N1 = OFF
P1 = OFF
= 1µA (typ)
I
Q
EN = 1, OR
TREN = 1
V
IN
1
0
COMPARATOR
EN = 0,
TREN = 0
EN = 0,
TREN = 0
AUTOMATIC TRACK
MODE (ATM)*
TRACK MODE*
V
< V ,
IN
TREN = 0
OUT
N1 = OFF
P1 = CURRENT-
LIMITED SWITCH
N1 = OFF
P1 = CURRENT-
LIMITED SWITCH
= 30µA (typ)
I
= 65µA (typ)
I
Q
Q
OUTPUT
BELOW TARGET
BOOST CIRCUITRY ENABLED
[V
V
< (0.72 x
V
< V ,
IN
TREN = 1
OUT
OUT
EN = 1,
> (V - 300mV)
)]
OUT_TARGET
V
OUT
IN
V
IN
V
IN
BOOST EXIT MODE
COMPARATOR = 0
COMPARATOR = 1
BOOST SOFT-START
EN = 0
N1 = OFF
P1 = OFF
IC WAITS UNTIL
N1 = SWITCHING
P1 = OFF
V
= V
IN
OUT
SOFT-START
VOLTAGE RAMP
COMPLETE
EN = 0
BOOST MODE
N1 = SWITCHING
P1 = SWITCHING
V
OUT
= V
OUT_TARGET
I
Q
= 45µA (SKIP MODE)
*EN TAKES PRIORITY OVER TREN. SEE TABLE 1.
Figure 2. State Diagram
10 _____________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
