IXTP220N04T2 View Datasheet(PDF) - IXYS CORPORATION
Part Name
Description
Manufacturer
IXTP220N04T2 Datasheet PDF : 11 Pages
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DC to DC Synchronous Converter Design
Abdus Sattar, IXYS Corporation
IXAN0068
The estimated efficiency, η = 39.6 = 0.93 = 93% %,
42.6
Estimated input current:
If we assume only 93% efficiency, then the estimated input current can be obtained,
Estimated
input
current,
I in
=
VoIo
Vin •η
=
3.3 •12
12 • 0.93
=
3.5A A
Bootstrap Circuit Design: [3]
Selecting bootstrap circuit components are done with consideration of the electrical rating
and characteristics of the high-side MOSFET (Q1).
The capacitance is defined by datasheet of IXS839 driver,
C BST
= QG(total )
ΔVBST
(24)
Where QG(total) is the total gate charge of high-side MOSFET (Q1), and ΔVBST is the
allowable voltage droop in Q1. Assume this voltage droop equal to 0.1V.
C BST
=
42nC
200mV
= 0.210uF
The bootstrap diode and capacitor voltage rating should be
V > V + V Bootstrap _ DiodeandCapacitor
IN
DD
The average forward current is defined by,
I F ( Avg ) = QG(total) • f SW
(25)
= 42 •10−9 • 250 •103 = 10.5mA
Bibliography
[1] “Synchronous Buck MOSFETs loss calculation” AN-6005, Jon Klein, Fairchild
Semiconductor, 01/04/2006, www.fairchildsemi.com
[2] “Examination of reverse recovery losses in a synchronous buck converter circuit”
Application Note from Silicon Semiconductor, 2003, www.siliconsemi.com
[3] Datasheet for ISL6594D “Advanced Synchronous Rectified Buck MOSFET Driver”
from Intersil Corporation, 2007, www.intersil.com
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