is127-overview-and-comparison-board-chargers-topologies-semiconductors-choices-and-synchronous-recti
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DC/DC stage:<br />
LLC resonant<br />
› Usually Full Bridge configuration for higher energy density<br />
› Most popular working above resonance (ZVS mode)<br />
› S1-S4: Typically Superjunction or SiC<br />
› D1-D4: Ultrafast Diode or SiC Schottky<br />
› Frequency range < 200kHz typically<br />
Vbus<br />
S1<br />
S2<br />
Lr<br />
Cr<br />
D1<br />
D3<br />
D2<br />
D4<br />
Lo<br />
Co<br />
Vbatt<br />
HV<br />
batt.<br />
Input <strong>and</strong> Output sinusoidal current =><br />
easier filtering <strong>and</strong> lower EMI<br />
50% duty cycle control<br />
Small or no output inductor => lower<br />
overvoltage on secondary diodes May<br />
allow 600V mosfet <strong>synchronous</strong><br />
<strong>recti</strong>fication<br />
Needs low value high voltage capacitor<br />
for resonance, also providing DC<br />
decoupling<br />
Simpler control strategy than ZVS-PS<br />
(frequency variation)<br />
Synchronous <strong>recti</strong>fication at secondary<br />
would require extra current or voltage<br />
sensing, since phase shift with input<br />
changes with load <strong>and</strong> Vbus<br />
S3<br />
S4<br />
Relevant losses on output bridge<br />
<strong>recti</strong>fier<br />
2017-05-11 Copyright © Infineon Technologies AG 2017. All rights reserved.<br />
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