This was achieved by having a green/active boot strap circuit internal to the control IC that was similar to that presented in Figure 2, which only dissipates/applies power to the controller during startup and turning off once the bias winding
of the transformer could deliver energy to power the control IC.
If voltage increases at the output, it will result in increased voltage at the output of the bias winding across C10.
The power supply also features a time-triggered overload protection function which is sensed from the primary side bias winding.
Using the company's integrated EcoSmart technology, TinySwitch-II enables a power supply design with high standby efficiency and low noload power consumption of under 250 mW at 265V AC input without a bias winding
on the transformer.