MP1584 – 3A, 1.5MHz, 28V STEP-DOWN CONVERTER
BLOCK DIAGRAM
V
VIN
IN
+
--
+
--
5V
2.6V
REFERENCE UVLO/
INTERNAL
REGULATORS
EN
THERMAL
SHUTDOWN
BST
SW
SW
--
+
I
SW
1.5ms SS
SS
V
OUT
I
Level
Shift
SW
FB
Gm Error Amp
--
+
COMP
SS
0V8
OSCILLATOR
CLK
V
OUT
FREQ
GND
COMP
Figure 1—Functional Block Diagram
OPERATION
The MP1584 is
non-synchronous,
a
variable frequency,
PWM Control
step-down switching
At moderate to high output current, the MP1584
operates in a fixed frequency, peak current
control mode to regulate the output voltage. A
PWM cycle is initiated by the internal clock. The
power MOSFET is turned on and remains on
until its current reaches the value set by the
COMP voltage. When the power switch is off, it
remains off for at least 100ns before the next
cycle starts. If, in one PWM period, the current
in the power MOSFET does not reach the
COMP set current value, the power MOSFET
remains on, saving a turn-off operation.
regulator with an integrated high-side high
voltage power MOSFET. It provides a highly
efficient solution with current mode control for
fast loop response and easy compensation. It
features a wide input voltage range, internal
soft-start control and precision current limiting.
Its very low operational quiescent current
makes it suitable for battery powered
applications.
MP1584 Rev. 1.0
8/8/2011
www.MonolithicPower.com
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