Test Procedure
6
Test Procedure
6.1
Line/Load Regulation and Efficiency Measurement Procedure
1. Set up EVM as described in
and
2. Ensure Load is set to constant resistance mode and to sink 0Adc
3. Ensure all jumpers configuration settings per section 5.
4. Ensure the jumper provided in the EVM shorts on J6 before Vin is applied.
5. Increase Vin from 0V to 12V. Using V1 to measure input voltage.
6. Remove the jumper on J6 to enable the controller.
7. Use V2 to measure Vout voltage.
8. Vary Load from 0-14Adc, Vout should be remain in load regulation.
9. Vary Vin from 8V to 20V, Vout should remain in line regulation.
10. Put the jumper on J6 to disable the controller.
11. Decrease Load to 0A
12. Decrease Vin to 0V.
6.2
Control Loop Gain and Phase Measurement Procedure
TPS53319EVM-136 contains a 10
Ω
series resistor in the feedback loop for loop response analysis.
1. Set up EVM as described in
and
2. Connect isolation transformer to test points marked TP6 and TP7.
3. Connect input signal amplitude measurement probe (channel A) to TP6. Connect output signal
amplitude measurement probe (channel B) to TP7.
4. Connect ground lead of channel A and channel B to TP9.
5. Inject around 20mV or less signal through the isolation transformer.
6. Sweep the frequency from 100Hz to 1MHz with 10Hz 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).
6.3
List of Test Points
Table 6. The Functions of Each Test Points
Test Points
Name
Description
TP1
VIN
Controller input
TP2
Vout
Output Voltage
TP3
VREG
5V LDO output
TP4
PGOOD
Power Good
TP5
EN
Enable
TP6
CHA
Input A for loop injection
TP7
CHB
Input B for loop injection
TP8
LL
Switching node
TP9
GND
Ground
TP10
GND
Ground
TP11
GND
Ground
TP12
GND
Ground
8
High Efficiency 14A Synchronous Buck Converter with Eco-Mode™
SLVU728 – May 2012
Copyright © 2012, Texas Instruments Incorporated
