Texas Instruments TPS54331, Руководство пользователя

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2.8 Input Voltage Ripple
The TPS54331EVM-232 input voltage ripple is shown in Figure 2-8 . The output current for each device is at full
rated load of 3 A.
V
IN
PH
t - Time - 1 s/div
m
Figure 2-8. TPS54331 Input Ripple
2.9 Powering Up
The start-up waveform is shown in Figure 2-9 and Figure 2-10 . In Figure 2-9 , the top trace shows Vin, and the
bottom trace shows Vout. In Figure 2-9 , the top trace shows EN (enable) whereas the bottom trace shows Vout.
Initially, the input voltage is applied and the output is inhibited by using a jumper at J2 to tie EN to GND. When
the jumper is removed, EN is released. When the EN voltage reaches the enable-threshold voltage of 1.25 V, the
start-up sequence begins and the internal reference voltage begins to ramp up at the internally set rate toward
0.8 V and the output voltage ramps up to the externally set value of 3.3 V.
V
IN
V
OUT
t - Time - 5 ms/div
Figure 2-9. TPS54331 Start-Up Relative to Vin
Test Setup and Results www.ti.com
8 TPS54331 Step-Down Converter Evaluation Module User's Guide SLVU247A – JULY 2008 – REVISED OCTOBER 2021
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