Texas Instruments TPS54291EVM-431, Руководство пользователя, Страница: 10 / 18

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TPS54291EVM-431 Typical Performance Data and Characteristic Curves
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2. Vary LOAD1 from 0 – 1.5Adc
3. Vary LOAD2 from 0 – 2.5Adc
4. Vary V
IN
from 9.6Vdc to 13.2Vdc
5. Decrease V
IN
to 0Vdc
6. Decrease LOAD1 to 0A
7. Decrease LOAD2 to 0A
4.4 Output Ripple Voltage Measurement Procedure
See Section 5.4 for more information on measuring output ripple.
1. Increase V
IN
from 0V to 12Vdc
2. Adjust LOAD1 to desired load between 0Adc and 1.5Adc
3. Adjust LOAD2 to desired load between 0Adc and 2.5Adc
4. Adjust V
IN
to desired load between 9.6Vdc and 13.2Vdc
5. Connect Oscilloscope Probe to TP3 and TP4 or TP18 and TP19 as shown in Figure 3
6. Measure Output Ripple
7. Decrease V
IN
to 0Vdc
8. Decrease LOAD1 to 0A
9. Decrease LOAD2 to 0A
4.5 Control Loop Gain and Phase Measurement Procedure
1. Connect 1kHz–1MHz Isolation Transformer to TP6 and TP8 as show in Figure 4
2. Connect Input Signal Amplitude Measurement Probe (Channel A) to TP8 as shown in Figure 4
3. Connect Output Signal Amplitude Measurement Probe (Channel B) to TP6 as shown in Figure 4
4. Connect Ground Lead of Channel A and Channel B to TP5 and TP7 as shown in Figure 4
5. Inject 30mV or less signal across R1 through Isolation Transformer
6. Sweep Frequency from 1kHz to 1MHz with 10Hz or lower post filter
7. Control Loop Gain can be measured by
8. Control Loop Phase is measured by the Phase difference between Channel A and Channel B
9. Control Loop for Channel 2 can be measured by making the following substitutions
(a) Change TP6 to TP16
(b) Change TP8 to TP14
(c) Change TP5 to TP17
(d) Change TP7 to TP15
10. Disconnect Isolation Transformer before making any other measurements (Signal Injection into
Feedback may interfere with accuracy of other measurements)
4.6 Equipment Shutdown
1. Shut Down Oscilloscope
2. Shut down V
IN
3. Shut down LOAD1
4. Shut down LOAD2
5. Shut down FAN
5 TPS54291EVM-431 Typical Performance Data and Characteristic Curves
Figure 5 through Figure 7 present typical performance curves for the TPS54291EVM-431. Since actual
performance data can be affected by measurement techniques and environmental variables, these curves
are presented for reference and may differ from actual field measurements.
10 Using the TPS54291EVM-431 A 12V Input, 3.3V 1.5A and 1.2V 2.5A SLVU356 – January 2010
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