Low-Cost, High-Frequency, Current-Mode PWM
Buck Controller
Functional Diagram
IN
MAX1953/MAX1954/MAX1957
THERMAL
LIMIT
UVLO
MAX1953
MAX1954
MAX1957
SHUTDOWN
COMPARATOR
SLOPE
COMPENSATION
HSD
(MAX1954
ONLY)
0.5V
COMP
ERROR
AMPLIFIER
FB
PWM
CONTROL
CIRCUITRY
CURRENT-
SENSE
CIRCUITRY
BST
DH
GND
LX
IN
DL
REFIN
(MAX1957
ONLY)
REFERENCE
AND
SOFT-START
DAC
SHORT-CIRCUIT
CURRENT-LIMIT
CIRCUITRY
CURRENT-LIMIT
COMPARATOR
PGND
CLOCK
ILIM
(MAX1953
ONLY)
Typical Operating Circuit
INPUT
3V TO 5.5V
ILIM
IN
BST
DH
MAX1953
COMP
LX
DL
PGND
OUTPUT
0.8V TO 0.86V
IN
GND
FB
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