Texas Instruments UCC29950EVM-631, Руководство пользователя, Страница: 18 / 38

Frequency (Hz)
Gain
(dB)
Phase (
°)
10 100 1000 10000
-180 -180
-140 -140
-100 -100
-60 -60
-20 -20
20 20
60 60
100 100
140 140
180 180
D001 D008 D002
Gain
Phase
Frequency (Hz)
Gain
(dB)
Phase (
°)
10 100
-40 -50
-20 0
0 50
20 100
D001 D008 D002
Gain
Phase
Frequency (Hz)
Gain
(dB)
Phase (
°)
10 100
-40 -50
-20 0
0 50
20 100
D001 D008 D002
Gain
Phase
Performance Data and Typical Characteristic Curves
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7 Performance Data and Typical Characteristic Curves
Figure 12 through Figure 33 present typical performance curves for the UCC9950EVM-631.
7.1 PFC Stage Loop Stability
The UCC29950 uses a new Hybrid Average Current control method. The loop compensation is
implemented digitally thus eliminating the need for external compensation components. The Bode Plots
below were taken from a typical EVM and show a loop crossover frequency of 9Hz with a phase margin of
greater than 60°.
Figure 9. PFC Loop Gain/Phase at 300 W, 115 V Figure 10. PFC Loop Gain/Phase at 300 W, 230 V
7.2 LLC Stage Loop Stability
The gain and phase characteristic of the LLC stage is dominated by the external components in the
feedback loop rather than by the UCC29950 itself. The Bode Plots below were taken from a typical EVM
and show a loop crossover frequency of approximately 1.1kHz with a phase margin of greater than 45°.
Figure 11. Gain/Phase vs. Frequency
18 Using the UCC29950EVM-631 300-W PFC/LLC Off-Line PSU Module SLUUB69A – March 2015 – Revised March 2015
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