When the TPS563201 and TPS563208 are in the normal CCM operating mode and the switch current falls to 0 A, the TPS563201 begins operating in pulse skipping Eco-mode. Each switching cycle is followed by a period of energy saving sleep time. The sleep time ends when the VFB voltage falls below the Eco-mode threshold voltage. As the output current decreases, the perceived time between switching pulses increases.