Datasheet

MetalGroundBarrel
ProbeTip
TP9 TP10
TipandBarrelOutputRippleMeasurement
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ChannelA
ChannelB
LOG20
Test Set Up www.ti.com
Figure 3. Output Ripple Measurement
4.3 Start Up and Test Procedure
1. Ensure LOAD is set to constant current mode and to sink 0 Adc.
2. Increase V
IN
from 0 V to 10.8 Vdc, V
OUT
should be in regulation per Table 1. Continue increasing V
IN
to
12 V.
3. Vary LOAD from 0 to 32 Adc, V
OUT
should remain in regulation per Table 1.
4. Vary V
IN
from 10.8 Vdc to 13.2 Vdc, V
OUT
should remain in regulation per Table 1.
5. For various V
IN
settings vary LOAD from 0 to 32 Adc. V
OUT
should remain in regulation per Table 1 for
all combinations of load on LOAD up to 32 A.
4.4 Control Loop Gain and Phase Measurement Procedure
1. Connect 1 kHz–1 MHz Isolation Transformer to test points marked CHA and CHB.
2. Connect Input Signal Amplitude Measurement Probe (Channel A) to CHA.
3. Connect Output Signal Amplitude Measurement Probe (Channel B) to CHB.
4. Connect Ground Lead of Channel A and Channel B to AGND
5. Inject 25 mV or less signal through the Isolation Transformer.
6. Sweep Frequency from 100 Hz to 1 MHz with 10 Hz 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. Disconnect Isolation Transformer from the bode plot test points before making other measurements
(Signal Injection into Feedback may interfere with accuracy of other measurements).
8
Using the TPS40140EVM-003 A 32-A Single Output Two-Phase Stackable SLVU219A–August 2007–Revised November 2010
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