Hig h -Effic ie n c y, P WM, S t e p -Do w n
DC-DC Co n t ro lle rs in 1 6 -P in QS OP
CSH
CSL
2.5V (1V, MAX1655)
FROM
FEEDBACK
DIVIDER
MAIN PWM
COMPARATOR
BST
DH
LX
R
S
Q
LEVEL
SHIFT
SLOPE COMP
OSC
IDLE MODE
COMPARATOR
2–MAX165
SKIP
(MAX1653/
MAX1655
ONLY)
25mV
VL
4µA
CURRENT
LIMIT
SHOOT-
THROUGH
CONTROL
24R
1R
SS
2.5V
N
SHDN
SYNCHRONOUS-
RECTIFIER CONTROL
VL
DL
R
Q
LEVEL
SHIFT
-100mV
S
PGND
REF (MAX1652)
GND (MAX1654)
COMPARATOR
(NOTE 1)
1µs
SINGLE-SHOT
SECFB
MAX1652, MAX1654 ONLY
NOTE 1: COMPARATOR INPUT POLARITIES
ARE REVERSED FOR THE MAX1654.
Figure 3. PWM Controller Detailed Block Diagram
14 ______________________________________________________________________________________