7.2.3 Regulation Comparator

The feedback voltage at the FB pin is compared to a 0.6 V internal reference. In normal operation (the output voltage is regulated), an on-time period is initiated when the voltage at the FB pin falls below 0.6 V. The main MOSFET stays on for the programmed on-time, causing the output voltage to rise and consequently the voltage of the FB pin to rise above 0.6 V. After the on-time period, the main MOSFET stays off until the voltage of the FB pin falls below 0.6 V again. Bias current at the FB pin is nominally 1 nA.