SLVSDA7E February 2017 – August 2019 TPS61178
The TPS61178 integrates a Power Save Mode with pulse frequency modulation ( PFM ) at the light load. When a light load condition occurs, the COMP pin voltage naturally decreases and reduces the peak current. When the COMP pin voltage further goes down with the load lowered and reaches the pre-set low threshold, the output of the error amplifier is clamped at this threshold and does not go down any more. If the load is further lowered, the output voltage of TPS61178 exceeds the nominal voltage and the device skips the switching cycles and regulate the output voltage at a higher threshold (typical 101%*VOUT_NORMAL).
The Auto PFM mode reduces the switching losses and improves efficiency at the light load condition by reducing the average switching frequency.