Datasheet

L6599A Application information
Doc ID 15308 Rev 7 29/35
Equation 13
where Qg is the gate charge of the external Power MOSFET, R
(DS)ON
is the on-resistance of
the bootstrap DMOS (150 W, typ.) and T
charge
is the ON-time of the bootstrap driver, which
equals about half the switching period minus the deadtime T
D
. For example, using a
MOSFET with a total gate charge of 30 nC, the drop on the bootstrap driver is about 3 V at a
switching frequency of 200 kHz:
Equation 14
If a significant drop on the bootstrap driver is an issue, an external ultra-fast diode can be
used, therefore saving the drop on the R
(DS)ON
of the internal DMOS.
Fon)DS(
eargch
g
Fon)DS(eargchDrop
VR
T
Q
VRIV +=+=
V7.26.0150
1027.0105.2
1030
V
66
9
Drop
=+
⋅−⋅
⋅
=
−−
−