Information
5
Portable Power Conversion Design Guide
DC/DC Conversion
Step-Down (Buck) Switch Mode Power Converters
MCP16311 12V Buck-Boost Application
Some power supplies require the ability step the voltage up or down from the input to the output. This is particularly useful
in battery-powered applications where the battery voltage may be above or below the desired output voltage, depending on
the type of battery used or battery charge remaining. By adding a few additional circuit components, the MCP16311 can be
adapted to work in a buck-boost topology that would address this issue. The application can either buck or boost the input
voltage in order to maintain the output voltage, operating from a 6V to 18V input and providing up to 300 mA of output current.
MCP16311 Buck-Boost Application Circuit
BOOST
A
GND PGND
VCC
VIN
SW
EN
FB
56 μH
L
1
30V n-Channel
MOSFET
Q
1
40V Schottky Diode
D
1
C
1
10 µF
RT
10 kΩ
RB
140 kΩ
C
4
10 µF
C
3
10 µF
C
2
10 µF
C
VCC
1 µF
GND
1
VOUT
VIN = 4.5V to 18V
GND
REN 1 MΩ
S
D
G
R
6
4.7Ω