MC34067, MC33067
The maximum duty cycle is controlled by the leakage
so that the output switch is activated while the primary
current is slewing but before the current changes polarity.
The resonant stage should then be designed to be as long as
the time for the primary current to go to 0 A.
inductance, not by the MC34067. The One−Shot in the
MC34067 only assures that the power switch is turned on
under a zero voltage condition. Adjust the one−shot period
5.1 V
C
OSC
3.6 V
5.1 V
3.6 V
One−Shot
Drive Output A
Drive Output B
V
in
Input Voltage 1/2 V
in
0 V
+ I
primary
0 A
Primary Current
− I
primary
V /Turns Ratio
in
Output Rectifier Voltage
Figure 21. Application Timing Diagram
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