Test Procedure

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6.3

VDD Pin Supply Selection

The controller can be enabled and disabled by J7.

Table 4. Enable Selection

SET ON CONNECTION

ENABLE SELECTION

R19 = 0

Ω

(1)

VDD pin connected to VIN pins

(1)

R19 = Open

VDD pin disconnected to VIN pins

(1)

Default setting: the VDD pin connected to the VIN pins through R19.

For power-up, input J7 with proper voltage. The VDD pin input voltage range is from 4.5 V to 25 V.

7

Test Procedure

7.1

Line and Load Regulation and Efficiency Measurement Procedure

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

2. Ensure the load is set to constant-resistance mode and to sink at 0 ADC.

3. Ensure all jumper setting are configured as shown in Section 6.

4. Ensure the jumper provided in the EVM shorts on J2 before VIN is applied.

5. Increase VIN from 0 to 12 V. Use V1 to measure input voltage.

6. Remove the jumper on J2 to enable the controller.

7. Use V2 to measure the VOUT voltage.

8. Vary the load from 0 to 10 ADC, VOUT must remain in load regulation.

9. Vary VIN from 8 to 14 V, VOUT must remain in line regulation.

10. To disable the converter, place the jumper on J2.

11. Decrease the load to 0 A

12. Decrease VIN to 0 V.

7.2

Control-Loop Gain and Phase-Measurement Procedure

The TPS53515EVM-PWR587 contains a 10-

Ω series resistor in the feedback loop for loop response

analysis.

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

2. Connect the isolation transformer to the test points marked TP5 and TP8.

3. Connect the input-signal amplitude-measurement probe (channel A) to TP10. Connect the output-

signal amplitude-measurement probe (channel B) to TP11.

4. Connect the ground lead of channel A and channel B to TP15.

5. Inject around 20 mV or less signal through the isolation transformer.

6. To measure control-loop gain and phase margin, change the frequency from 100 Hz to 1 MHz using a

10-Hz or less post filter.

7. Disconnect the isolation transformer from the bode-plot test points before making other measurements.

•

Signal injection into feedback can interfere with the accuracy of other measurements.

8

High Performance 12-A, Single-Synchronous, Step-Down Converter Using

SLUUAS1B – October 2013 – Revised February 2014

the TPS53515EVM-PWR587

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