MIC4100BM Micrel Inc, MIC4100BM Datasheet - Page 11

• Manufacturer Part Number: MIC4100BM
• Description: IC,Dual MOSFET Driver,SOP,8PIN,PLASTIC
• Manufacturer: Micrel Inc

Specifications of MIC4100BM

• Configuration: Half Bridge
• Input Type: Non-Inverting
• Delay Time: 27ns
• Current - Peak: 2A
• Number Of Configurations: 1
• Number Of Outputs: 2
• High Side Voltage - Max (bootstrap): 118V
• Voltage - Supply: 9 V ~ 16 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

High-Side Driver and Bootstrap Circuit
A block diagram of the high-side driver and bootstrap
circuit is shown in Figure 4. This driver is designed to drive
a floating N-channel MOSFET, whose source terminal is
referenced to the HS pin.
C
A low power, high speed, level shifting circuit isolates the
low side (VSS pin) referenced circuitry from the high-side
(HS pin) referenced driver. Power to the high-side driver
and UVLO circuit is supplied by the bootstrap circuit while
the voltage level of the HS pin is shifted high.
The bootstrap circuit consists of an internal diode and
external capacitor, C
Micrel, Inc.
B
March 2006
Vss
Vdd
Vdd
B
. In a typical application, such as the
LO
HS
Figure 3
Figure 4
HB
HO
External
FET
External
FET
11
synchronous buck converter shown in Figure 5, the HS pin
is at ground potential while the low-side MOSFET is on.
The internal diode allows capacitor C
Vdd-Vd during this time (where Vd is the forward voltage
drop of the internal diode). After the low-side MOSFET is
turned off and the HO pin turns on, the voltage across
capacitor C
MOSFET. As the upper MOSFET turns on, voltage on the
HS pin rises with the source of the high-side MOSFET until
it reaches Vin. As the HS and HB pin rise, the internal
diode is reverse biased preventing capacitor C
discharging.
C
VDD
HI
LI
Level
shift
Vdd
B
is applied to the gate of the upper external
Vss
HB
Figure 5
HO
C
HS
LO
B
Vin
B
Q1
Q2
to charge up to
Lout
M9999-031506
MIC4100/1
B
from
Cout
Vout