Evm Performance Validation - Texas Instruments TPSF12C3QEVM User Manual

EVM Setup, Connections and Validation
Connect INJ to the inject capacitor, C
X-capacitor star-point for a three-wire system). The X-capacitors at this position set a low impedance between
the power lines from a CM standpoint – this means that a single inject capacitor is adequate for AEF current
injection. Finally, connect a nominal 12-V bias supply from VDD to GND to power the AEF circuit.

4.3 EVM Performance Validation

1. Before plugging in the EVM to the EMI filter board, connect the bottom terminals of the sense and inject
Y-caps to GND (Earth or chassis ground connection).
2. Turn the regulator ON. Perform measurements of the common-mode and total EMI to benchmark the
existing passive filter solution. Extract the common-mode component using a DM/CM separator between the
LISN and EMI test receiver.
3. Turn the regulator OFF. Wait for all high-voltage capacitors to fully discharge.
4. Plug in the EVM to the main filter board.
5. Apply a VDD bias supply voltage of 8 V to 16 V (nominal 12 V) with ripple voltage less than 50 mV
peak-to-peak.
6. Probe the INJ pin of the EVM with respect to GND – it must be stable with a DC level of V
pin voltage is oscillating, some of the passive components on the EVM must be modified.
7. If the INJ pin voltage is stable, turn the regulator ON. Repeat the measurements for common-mode and total
EMI.
8. Power down the regulator and EVM.
9. If the EMI measurement in step 5 is lower compared to the result in step 2, the AEF circuit functions
correctly. Conversely, if the EMI measurement in step 5 is NOT lower than that from step 2, probe the INJ pin
voltage while the regulator is operational. Ensure that the INJ pin voltage is not getting clipped close to the
positive or negative supply rails (within 2 V of each rail).
• If the INJ pin voltage is getting clipped, increase the inject capacitance or the regulator-side Y-
capacitance values.
The sense and inject capacitors are Y-rated components supplied by the user, and the EVM as
provided is essentially a low-voltage design. Typical values for the sense and inject capacitances
are 680 pF and 4.7 nF, respectively. Depending on the EMI filter implementation in the target
application, the default damping and compensation component values installed on the EVM can
require suitable modification by the user to achieve acceptable loop stability. Check the variation
of effective capacitance values (of the inject capacitor in particular) over the applicable operating
temperature range.
Refer to the TPSF12C3-Q1 Standalone Active EMI Filter for Common-mode Noise Mitigation in
Three-Phase AC Automotive Power Systems
additional context pertaining to EVM component selection and optimization.
8 TPSF12C3QEVM Active EMI Filter Evaluation Module for Three-Phase AC
Power Systems
, whose opposite terminal then connects to the NEUTRAL line (or to the
INJ
Note
data sheet and
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/2. If the INJ
VDD
for
SLVUCM2 – JANUARY 2023
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