ZHCSCA8A March 2014 – April 2019 TPS65286
PRODUCTION DATA.
When a synchronous buck converter operates at light load condition, TPS65286 operates with pulse skipping mode (PSM) to reduce the switching loss by keeping the power transistors in the off-state for several switching cycles, while maintaining a regulated output voltage. The output voltage, load and inductor current diagrams are shown in Figure 30. When the VCOMP falls lower than VGS, the COMP terminal voltage is clamped to VGS internally, typical 350 mV, the device enters pulse skipping mode and high side MOSFET stops switching, then the output falls and the VCOMP rises. When the VCOMP rises larger than VGS, the high side MOSFET starts switching, then the output rises and the VCOMP falls. When the VCOMP falls lower than VGS, the high side MOSFET stops switching again. If the peak inductor current rise above typical 600 mA (VIN = 24 V, VOUT = 5 V) and the COMP terminal voltage to rise above VGS, the converter exits pulse skipping mode. Since converter detects the peak inductor current for pulse skip mode, the average load current entering pulse skipping mode varies with the applications and external output filters.
Figure 30. Pulse Skipping Mode