AAT1162 View Datasheet(PDF) - Analog Technology Inc
Part Name
Description
MFG CO.
'AAT1162' PDF : 16 Pages View PDF
AAT1162
12V, 1.5A Step-Down DC/DC Converter
Functional Block Diagram
AIN
LDO
Note 1
FB
Internal
Power
Current
Sense Amp +
LDO
-
+
Error
Amp -
+
-
Current
Mode
Comparator
Control
Logic
Reference
EN
IN
LX
PGND
AGND
DGND
COMP
Note 1: For fixed output voltage versions, FB is connecte. d to the
error amplifier through the resistive voltage divider shown.
Functional Description
The AAT1162 is a current-mode step-down DC/DC
converter that operates over a wide 4V to 13.2V
input voltage range and is capable of supplying up
to 1.5A to the load with the output voltage regulated
as low as 0.6V. Both the P-channel power switch
and N-channel synchronous rectifier are internal,
reducing the number of external components
required. The output voltage is adjusted by an exter-
nal resistor divider; fixed output voltage versions are
available upon request. The regulation system is
externally compensated, allowing the circuit to be
optimized for each application. The AAT1162
includes cycle-by-cycle current limiting, frequency
foldback for improved short-circuit performance, and
thermal overload protection to prevent damage in
the event of an external fault condition.
10
Control Loop
The AAT1162 regulates the output voltage using
constant frequency current mode control. The
AAT1162 monitors current through the high-side P-
channel MOSFET and uses that signal to regulate
the output voltage. This provides improved tran-
sient response and eases compensation. Internal
slope compensation is included to ensure the cur-
rent "inside loop" stability.
High efficiency is maintained under light load con-
ditions by automatically switching to variable fre-
quency Light Load control. In this condition, transi-
tion losses are reduced by operating at a lower fre-
quency at light loads.
1162.2007.09.1.2
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