Panasonic DMR-E75VP Service Manual page 13

Startup Circuit Timing Chart
Function of Z/C Terminal
When voltage of Z/C reaches 0.25V, Gate signal is output and Drain current starts to flow.
Function of F/B terminal
F/B signal decides Switching ON width in low voltage controlling.
The Switching ON width responds to change of F/B Voltage.
Standby Function
When Z/C Voltage becomes less than 3V, the unit changes to Standby mode.
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DMR-E75VP