Datasheet
Bootstrap driver L6387E
10/17 DocID13990 Rev 4
For example: using a power MOSFET with a total gate charge of 30 nC the drop on the
bootstrap DMOS is about 1 V, if the T
charge
is 5s. In fact:
Equation 3
V
drop
has to be taken into account when the voltage drop on C
BOOT
is calculated: if this drop
is too high, or the circuit topology doesn’t allow a sufficient charging time, an external diode
can be used.
Figure 3. Bootstrap driver
V
drop
30nC
5s
-------------- - 125 0.8V=
TO LOAD
D99IN1056
H.V.
HVG
a
b
LVG
HVG
LVG
C
BOOT
TO LOAD
H.V.
C
BOOT
D
BOOT
V
BOOT
V
S
V
S
V
OUT
V
BOOT
V
OUT