MP2144 – 2A, 5.5V, 1.2MHz. 40μA IQ, SYNCHRONOUS STEP-DOWN SWITCHER
FUNCTIONAL BLOCK DIAGRAM
VIN
Bias
&
Voltage
Soft start /off
EN
+
COMP
VTH
Reference
-
Lo-Iq
Main
Switch
(PCH)
0.6V
RST
PDRV
+
+
-
PWM
Constant
On-Time
Pulse
E.A.
PWM
Lo-Iq
+
+
-
EN
SW
FBCOMP
Lo-Iq
Driver
FB
VOUT
Synchronous
Rectifier
Ramp
generator
SW
(NCH)
NDRV
Lo-Iq
Hi-Z
OUT
IN
PGND
0.66V
FB for
fixed output
+
+
COMP
COMP
-
-
Lo-Iq
+
COMP
AGND
PG
0.54V
-
Figure 1: Functional Block Diagram
MP2144 Rev. 1.03
12/20/2012
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