LM2647
www.ti.com
SNVS210F –JUNE 2003–REVISED APRIL 2013
LM2647 Dual Synchronous Buck Regulator Controller
Check for Samples: LM2647
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FEATURES
DESCRIPTION
The LM2647 is an adjustable 200-500kHz dual
channel voltage-mode controlled high-speed
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Input Voltage Range from 5.5V to 28V
Synchronous Dual-channel Interleaved
Switching
synchronous buck regulator controller ideally suited
for battery powered applications such as laptop and
notebook computers. The LM2647 requires only N-
channel FETs for both the upper and lower positions
of each synchronous stage. It features line
feedforward to improve the response to input
transients. At very light loads, the user can choose
between the high-efficiency Pulse-skip mode or the
constant frequency Forced-PWM mode. Lossless
current limiting without the use of external sense
resistors is made possible by sensing the voltage
drop across the bottom FET. A unique adaptive duty
cycle clamping technique is incorporated to
significantly reduce peak currents under abnormal
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Forced-PWM or Pulse-skip Modes
Lossless Bottom-side FET Current Sensing
Adaptive Duty Cycle Clamping
High Current N-channel FET Drivers
Low Shutdown Supply Currents
Reference Voltage Accurate to Within ±1.5%
Output Voltage Adjustable down to 0.6V
Power Good flag and Chip Enable
Under-voltage Lockout
Over-voltage/Under-voltage Protection
Soft-start and Soft-shutdown
load
conditions.
The
two
independently
programmable outputs switch 180° out of phase
(interleaved switching) to reduce the input capacitor
and filter requirements. The input voltage range is
5.5V to 28V while the output voltages are adjustable
down to 0.6V.
Switching Frequency Adjustable 200kHz-
500kHz
APPLICATIONS
Standard supervisory and control features include
Soft-start, Power Good, output Under-voltage and
Over-voltage protection, Under-voltage Lockout, Soft-
shutdown and Enable.
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Notebook Chipset Power Supplies
Low Output Voltage High-Efficiency Buck
Regulators
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