Care in design of the transformer and VC bias circuit is required to obtain hiccup overload protection. Leading-edge voltage overshoot on the bias winding may cause VC to peak-charge, preventing the expected tracking with output voltage. Some method of controlling this is usually required. This may be as simple as a series resistor, or an R-C filter in front of DVC1. Good transformer bias-to-output-winding coupling results in reduced overshoot and better voltage tracking.
RVC as shown in Figure 29 helps to reduce peak charging from the bias winding. This becomes especially important when tuning hiccup mode operation during output overload. Typical values for RVC will be from 10 Ω to 100 Ω.