Figure 4-3 shows the efficiency of TPS61299 with Vout =5 V, under different input voltage. As is seen, the efficiency under 1uA ultra light load can still keep above 70% when Vin higher than 3.0 V. Especially, the efficiency when output current higher than 6mA can maintain as high as 95% ( when Vin=4.3 V) , which is the same with normal mode.

Figure 4-4 shows the regulation of TPS61299 with Vout =5 V, under different input voltage.