AS1349 Austin Semiconductor, AS1349 Datasheet - Page 9

• Manufacturer Part Number: AS1349
• Description: (AS1346 - AS1349) Dual Step Down Converter
• Manufacturer: Austin Semiconductor

AS1346, AS1347, AS1348, AS1349
Datasheet - D e t a i l e d D e s c r i p t i o n
8 Detailed Description
The AS1346, AS1347, AS1348, AS1349 family is a high-efficiency buck converter that uses a constant-frequency cur-
rent-mode architecture. The device contains two internal MOSFET switches and is available with a fixed output voltage
(see Ordering Information on page
Figure 17. AS1346 - Block Diagram
Main Control Loop
During normal operation, the internal top power MOSFET is turned on each cycle when the oscillator sets the RS latch.
This switch is turned off when the current comparator resets the RS latch. The peak inductor current (I
ICOMP resets the RS latch, is controlled by the error amplifier. When I
to the internal 0.6V reference, causing the error amplifier’s output voltage to increase until the average inductor current
matches the new load current.
www.austriamicrosystems.com/DC-DC_Step-Down/AS1346
EN1
EN2
FB2
FB1
LBI
Oscillator
Main Control
14).
Shutdown
Control
AS1346
Soft Start
Soft Start
AGND
Compare
Power-OK
Revision 1.01
Logic
Control
Control
PGND
Mosfet
Mosfet
Logic
Logic
VDD
LOAD
Current
Current
Sense
Sense
increases, V
VDD
FB
decreases slightly relative
PVIN
PVIN
PK
SW2
SW1
LBO
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) at which
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