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www.ti.com Efficiency
5 Efficiency
Figure 1. Efficiency
Figure 1 illustrates the efficiency of the converter vs. input voltage and output current. These curves
highlight the high efficiency of the converter, especially considering the simplicity of design offered by a
non synchronous implementation. Note the discontinuity in the curves at approximately 17 V and 13 V
which represent mode transition boundaries. The lower efficiencies in the buck-boost region reflect
additional losses at higher input and inductor currents. The decrease in efficiency at higher input voltages
represents higher switching losses.
6 Air Flow
Prolonged operation without airflow at low input voltage and at at full power will cause the MOSFET’s and
Diodes to overheat. A fan with a minimum of 200 LFM should always be provided. Figure 2 illustrates the
temperature rise of various components with no airflow. The ambient was 25°C, and V
IN
was 8 V.
Figure 2. Temperature vs Load Current With No Airflow – 25°C Ambient
3
SNVA614B–January 2012–Revised January 2014 AN-2205 LM25118 Evaluation Board
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