MAX17112 Maxim Integrated Products, MAX17112 Datasheet - Page 7

• Manufacturer Part Number: MAX17112
• Description: DC-DC Converter
• Manufacturer: Maxim Integrated Products

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Figure 2. Functional Diagram
The MAX17112 is a highly efficient, power-management
IC that employs a current-mode, fixed-frequency, PWM
architecture for fast-transient response and low-noise
operation. The high switching frequency (1MHz) allows
the use of ultra-small inductors and low-ESR ceramic
capacitors. The current-mode architecture provides fast-
transient response to pulsed loads. A compensation pin
(COMP) gives users flexibility in adjusting loop dynam-
ics. The internal MOSFET can generate output voltages
up to 20V from a 2.6V to 5.5V input voltage. The soft-
start function slowly ramps the input current and is pro-
grammable with an external capacitor. The input
overvoltage protection function prevents damage to the
MAX17112 from input surge voltages up to 24V.
V
IN
High-Performance, Step-Up, DC-DC Converter
V
IN
L
_______________________________________________________________________________________
Detailed Description
SHUTDOWN
OSCILLATOR
1.2MHz
SHDN
CLOCK
OVP
COMPARATOR
4μA
PWM
SS
SLOPE COMPENSATION
SOFT-START
LOGIC AND
DRIVER
IC SUPPLY
VOLTAGE
The error amplifier compares the signal at FB to 1.24V
and varies the COMP output. The voltage at COMP
determines the current trip point each time the internal
MOSFET turns on. As the load changes, the error
amplifier sources or sinks current to the COMP output
to command the inductor peak current necessary to
service the load. To maintain stability at high duty
cycles, a slope compensation signal is summed with
the current-sense signal. At light loads, this architecture
allows the device to skip cycles to prevent overcharg-
ing the output capacitors.
ERROR AMPLIFIER
CURRENT
SENSE
1.24V
FB
COMP
LX
GND
V
MAIN
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