Datasheet

V (ac coupled) = 50mV/div
OUT
I = 1A/div
La
I = 1A/div
Lb
SW = 10V/div
Time - 2 s/divm
V = 5V/div
OUT
V = 2V/div
IN
EN = 2V/div
SW = 20V/div
Time - 1ms/div
50
55
60
65
70
75
80
85
90
95
100
0 0.2 0.4 0.6 0.8 1 1.2
Output Current (A)
Efficiency (%)
V
IN
= 6 V
V
IN
= 12 V
V
IN
= 18 V
G026
V (ac coupled) = 200mV/div
OUT
I = 500mA/div
OUT
Time - 500 s/divm
100 1k 10k 100k
−60
−40
−20
0
20
40
60
−180
−120
−60
0
60
120
180
Frequency (Hz)
Gain (dB)
Phase (°)
6 V Input Gain
6 V Input Phase
G025
TPS55340
SLVSBD4B –MAY 2012–REVISED OCTOBER 2012 www.ti.com
Figure 25. SEPIC Power Stage Gain and Phase
As there are no changes in the transconductance amplifier, the equations used to calculate the external
compensation components in a boost design can be used in the SEPIC design. Using the maximum Gea from
the electrical specification of 440 µmho, Equation 38 calculates the nearest standard value of R3 to be 2.37 kΩ.
Using Equation 39, C4 is calculated to the nearest standard value of 0.1 µF.
CHARACTERISTICS OF THE SEPIC CONVERTER
Figure 26. Efficiency vs Output Current Figure 27. Load Transient Response
Figure 28. CCM PWM Operation Figure 29. Output Voltage Soft-start
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