Texas Instruments TPS40422 Dual Output or Multiphase Synchronous Buck Controller Evaluation Module TPS40422EVM-091 TPS40422EVM-091 데이터 시트
제품 코드
TPS40422EVM-091
Test Procedure
NOTE:
The IOUT_CAL_GAIN parameter is used by the TPS40422 in the calculation of output
current level, and this number is the dc resistance of the output inductor. Although this
number can be reconfigured, a number entry that does not match the actual DCR of the
inductor on the EVM will result in current reporting inaccuracy. This also affects OC Fault
and OC Warn performance.
number can be reconfigured, a number entry that does not match the actual DCR of the
inductor on the EVM will result in current reporting inaccuracy. This also affects OC Fault
and OC Warn performance.
The TON_RISE parameter may affect proper start-up if the rise time and output capacitance
bank result in a current that exceeds the OC Fault level. The start-up surge current in the
output capacitance bank is added to the load current, so the sum of these two currents must
be less than the OC Fault level for proper start-up.
bank result in a current that exceeds the OC Fault level. The start-up surge current in the
output capacitance bank is added to the load current, so the sum of these two currents must
be less than the OC Fault level for proper start-up.
6
Test Procedure
6.1
Line/Load Regulation and Efficiency Measurement Procedure
1. Set up the EVM as described in
and
2. Ensure that both electronic loads are set to draw 0 Adc.
3. Increase Vin from 0 V to 12 V using DMM1 to measure input voltage.
4. Use DMM2 to measure output voltage Vout1.
5. Vary the load from 0 Adc to 20 Adc. Vout1 must remain in regulation as defined in
.
6. Vary Vin from 8 V to 14 V. Vout1 must remain in regulation as defined in
7. Decrease the load to 0 A.
8. Use DMM3 to measure output voltage Vout2.
9. Vary the load from 0 Adc to 15 Adc. Vout1 must remain in regulation as defined in
.
10. Vary Vin from 8 V to 14 V. Vout2 must remain in regulation as defined in
11. Decrease the load to 0 A.
12. Decrease Vin to 0 V.
6.2
Control Loop Gain and Phase Measurement Procedure
The PWR091EVM includes a 49.9-
Ω
series resistor in the feedback loop for both Vout1 and Vout2. These
resistors are used for loop response analysis and are accessible at the test points TP8 and TP9 for Vout1,
and TP10 and TP12 for Vout2. Those test points must be used during loop response measurements as
the injection points for the loop perturbation. See the short descriptions listed in
and TP10 and TP12 for Vout2. Those test points must be used during loop response measurements as
the injection points for the loop perturbation. See the short descriptions listed in
Table 4. List of Test Points for Loop Response Measurements
Test Point
Node Name
Description
Comment
Input to feedback divider of
The amplitude of the perturbation at this node must be limited to
TP8
INPUT1
Vout1
less than 100 mV.
Bode plot data can be measured by a network analyzer as
TP9
OUTPUT1
Resulting output of Vout1
TP9/TP8.
Input to feedback divider of
The amplitude of the perturbation at this node must be limited to
TP12
INPUT2
Vout2
less than 100mV.
Bode plot data can be measured by a network analyzer as
TP10
VOUT2
Resulting output of Vout2
TP10/TP12.
Measure only one output at a time with the following procedure:
1. Set up the EVM as described in
and
2. For Vout1, connect the network analyzer
’
s isolation transformer from TP8 to TP9.
3. Connect the input signal measurement probe to TP8. Connect output signal measurement probe to
TP9.
4. Connect the ground leads of both probe channels to TP4.
5. On the network analyzer, measure the Bode plot data as TP9/TP8 (Out/In). The frequency sweep must
15
SLVU638
–
January 2012
Using the PWR091EVM Dual-Output DC/DC Analog With PMBus Interface
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©
2012, Texas Instruments Incorporated