MCP16301 MICROCHIP [Microchip Technology], MCP16301 Datasheet - Page 14

• Manufacturer Part Number: MCP16301
• Description: High Voltage Input Integrated Switch Step-Down Regulator
• Manufacturer: MICROCHIP [Microchip Technology]

MCP16301
FIGURE 4-3:
Shunt Boost Supply Regulation is used for low output
voltage converters operating from a wide ranging input
source. A regulated 3.0V to 5.5V supply is needed to
provide high side-drive bias. The shunt uses a Zener
diode to clamp the voltage within the 3.0V to 5.5V
range using the resistance shown in
To calculate the shunt resistance, the boost drive
current can be estimated using
DS25004A-page 14
12V
12V
V
V
C
IN
C
IN
IN
Shunt and External Boost Supply.
IN
R
SH
C1
Equation
EN
V
EN
V
Figure
IN
IN
4-1.
MCP16301
MCP16301
4-3.
VZ = 5.1V
GND
GND
Boost Diode
BOOST
BOOST
SW
SW
3.0V to 5.5V External Supply
FB
FB
I
I
EQUATION 4-1:
BOOST_TYP
BOOST_TYP
FW Diode
FW Diode
C
I
C
Boost Diode
BOOST
B
B
L
L
for 3.3V Boost Supply = 0.6 mA
for 5.0V Boost Supply = 0.8 mA.
=
C
I
C
BOOST_TYP
BOOST CURRENT
OUT
OUT
© 2011 Microchip Technology Inc.
R
R
R
R
V
TOP
BOT
TOP
BOT
V
OUT
OUT
×
2V
2V
1.5
mA