Datasheet

Test Procedure

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7 Test Procedure

7.1 Line/Load Regulation and Efficiency Measurement Procedure

1. Set up EVM as described in Section 5 and Figure 3.

2. Ensure Load is set to constant resistance mode and to sink 0 A

3. Ensure all jumpers set per Section 6.

4. Increase VIN from 0 V to 12 V. Using V1 to measure VIN voltage.

5. Open jumper J1 to enable the controller.

6. Use V2 to measure VOUT voltage, A1 to measure VIN current.

7. Vary load from 0 A

to 6 A

, VOUT should remain in load regulation.

8. Vary VIN from 8.0 V to 14 V, VOUT should remain in line regulation.

9. Short jumper J1 to disable the controller.

10. Decrease load to 0 A.

11. Decrease VIN to 0 V.

7.2 Control Loop Gain and Phase Measurement Procedure

TPS53313EVM-078 contains a 10-Ω series resistor in the feedback loop for loop response analysis.

1. Set up EVM as described in Section 5 and Figure 3.

2. Connect isolation transformer to test points marked TP12 and TP11.

3. Connect input signal amplitude measurement probe (channel A) to TP12. Connect output signal

amplitude measurement probe (channel B) to TP11.

4. Connect ground lead of channel A and channel B to TP13.

5. Inject around 10-mV or less signal through the isolation transformer.

6. Sweep the frequency from 500 Hz to 500 kHz with 10-Hz or lower post filter. The control loop gain and

phase margin can be measured.

7. Disconnect isolation transformer from bode plot test points before making other measurements (Signal

injection into feedback may interfere with accuracy of other measurements).

6-A Step-Down Regulator with Integrated Switcher SLUU819–December 2011

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