Texas Instruments TPS40190EVM-001, User Manual

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4.4 Control Loop Gain and Phase Measurement Procedure
1. Connect a 1-kHz to 1-MHz isolation transformer to TP2 and TP3 as shown in Figure 4-1 .
2. Connect an input signal amplitude measurement probe (Channel A) to TP2 as shown in Figure 4-1 .
3. Connect an output signal amplitude measurement probe (Channel B) to TP3 as shown in Figure 4-1 .
4. Connect the ground lead of Channel A and Channel B to TP 4 as shown in Figure 4-1 .
5. Inject 25-mV or less signal across R7 through an isolation transformer.
6. Sweep frequency from 1 kHz to 1 MHz with 10-Hz or lower post filter.
7. Control loop gain can be measured by
20 × LOG
CℎannelB
CℎannelA
.
8. Control loop phase is measured by the phase difference between Channel A and Channel B.
9. Disconnect the isolation transformer from TP2 and TP3 before making other measurements (signal injection
into feedback can interfere with accuracy of other measurements).
4.5 Equipment Shutdown
1. Shut down the oscilloscope.
2. Shut down LOAD1.
3. Shut down V
12V_IN
.
4. Shut down FAN.
5 TPS40190EVM Typical Performance Data and Characteristic Curves
Figure 5-1 and Figure 5-2 present typical performance curves for the TPS40190EVM-001. Since the actual
performance data can be affected by measurement techniques and environmental variables, these curves are
presented for reference and can differ from actual field measurements.
5.1 Efficiency
Figure 5-1. TPS40190EVM-001 Efficiency, V
IN
= 10 V to 14 V, V
OUT
= 1.5 V, I
OUT
= 0 A to 10 A
Test Setup www.ti.com
8 TPS40190 Buck Controller Evaluation Module User's Guide SLUU232A – SEPTEMBER 2005 – REVISED JANUARY 2022
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