The VDD-VEE output is the main output of the module. The power stage operation is determined by the sensed VDD-VEE voltage on FBVDD pin. As shown in Figure 7-1, the VDD-VEE voltage is sensed through a voltage divider R_{FBVDD_TOP} and R_{FBVDD_BOT}. When FBVDD voltage stays below the turn-off threshold, roughly 10 mV above the V_{FBVDD_REF}, the power stage operates, delivers power to the secondary side and makes the VDD-VEE output voltage rise. After the output reaches the turn-off threshold, the power stage turns off. Output voltage drops because of the load current. After the output voltage drops below the turn-on threshold, roughly 10 mV below the V_{FBVDD_REF}, the power stage is turned on again. With the accurate voltage reference and hysteresis control, the VDD-VEE output voltage can be regulated with high accuracy. To improve the noise immunity, a small capacitor of 330 pF should be added between FBVDD and VEE pins. Excessive capacitor slows down the hysteresis loop and can cause excessive output voltage ripple or even stability issue.