Texas Instruments TPS54614EVM 1.8-V SWIFT, User Manual, Page: 15 / 33

Efficiency
2-3 Setup and Test Results
2.2 Efficiency
The TPS54614 efficiency peaks at around 1.5 A of load current. At a full 6-A
load the efficiency drops to around 83% with a 5-V input source. The efficiency
shown in Figure 2–2 is typical for an ambient temperature of 25
°
C. The
efficiency is lower at higher ambient temperatures, due to temperature
variation in the drain-to-source resistance of the MOSFETs. The total board
losses are shown in Figure 2–3. The plots of Figure 2–4 and Figure 2–5 are
extended out to current levels where the TPS54614 junction temperature
reaches 125
°
C at 25
°
C ambient. When operating the TPS54614 past the 6-A
maximum current rating, care should be taken to ensure that the maximum
junction temperature does not exceed 125
°
C.
Figure 2–2. Measured Efficiency
60
65
70
75
80
85
90
95
0 1 2 3 4 5 6 7 8 9 10
Efficency – %
IL– Load Current – A
VI = 5 V
VI = 3.3 V
TA = 25
°
C
Figure 2–3. Measured Board Losses
0
1
2
3
4
5
6
0 1 2 3 4 5 6 7 8 9 10
Losses – W
VI = 3.3 V
VI = 5 V
IL– Load Current – A
TA = 25
°
C