AN1660 Datasheet, PDF (1/13 Pages) STMicroelectronics – ZVS RESONANT CONVERTER

AN1660
APPLICATION NOTE
ZVS RESONANT CONVERTER
FOR CONSUMER APPLICATION USING L6598 IC
by Helen Ding
In this paper we study the details of the Multi-resonant Zero-current-switching converter which has
smaller size and higher efficiency, and low noise operation. It will shown the design equations and
demoboard results of a high-end TV power supply using ST L6598.
The small size, high efficiency, and low noise operation makes the half bridge resonant topology
actrative for converters.
It will shown the design equations and demoboard test results of a high-end TV power supply us-
ing ST L6598.
1 CIRCUIT DESCRIPTION
The simplified schematic and operating waveforms are shown in Fig.1 and Fig.2.
Figure 1. Simplified Schematic
+BUS
DRIVER-H
Q1
DRIVER-L
Q2
VOUT
D1
C1
OUT
Time
L-1
L.2Mag
LOAD
D2
V@CRES
C2
Time
D03IN1425
This half-bridge converter consists of switching devices Q₁ & Q₂, resonant inductor L₁, magnetizing induc-
tor of transformer L₂, resonant capacitors C₁ & C₂, transformer T, rectifier diodes D₁ & D₂, output capac-
itor Cout. CQ₁ & CQ₂ are the parasitic capacitors of the Q₁ & Q₂. D_Q1 & D_Q2 are the parasitic reverse
diodes of Q₁ & Q₂.
Switching devices Q₁ & Q₂ repeat on and off alternately, and the on- and off-times are the same. 50% duty
cycle.
September 2003
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