
IR11672AS
V TH3
I DS
V DS
T1
V TH1
V TH2
Gate Drive
Blanking
T2
MOT
t BLANK
time
Figure 8: Resonant half-bridge operation waveform
MOT Protection Mode
The MOT protection prevents reverse current in SR MOSFET which could happen at light load if the MOT time is set very
long. The IC disables the gate output in the protection mode and automatically resume to normal operation as the load
increasing to a level where the SR current conduction time is longer than MOT.
This function works in both flyback and resonant half-bridge topologies. Figure 9 is an example in Flyback converter.
V DS
I SEC
Gate Drive
time
MOT
Sensed VD>V TH1 at
the end of MOT
Disable the next gate output
Figure 9: MOT Protection Mode
17
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? 2013 International Rectifier
Nov 6, 2013