Texas Instruments TPSF12C1QEVM User Manual page 4

Hardware
2 Hardware
2.1 EVM Description
The TPSF12C1QEVM, a daughter-card design that attaches to an existing passive EMI filter circuit in a single-
phase AC power system, showcases the CM EMI performance improvement or size reduction achievable with
the TPSF12C1, a single-phase power-supply filter IC.
The EVM can be used for evaluation and for system development of a single-phase EMI filter circuit and
application. The AEF circuit effectively replaces the two Y-capacitors normally placed between the CM chokes
(and tied to chassis ground) in a conventional two-stage, fourth-order passive CM filter design. The design uses
a recommended PCB layout
The damping and compensation component values included with this EVM can require modification
if the passive filter components (the CM chokes in particular) are changed. Refer to the
Standalone Active EMI Filter for Common-mode Noise Mitigation in Three-Phase AC Power Systems
data sheet and TPSF12C1 quickstart calculator
operation, loop gain and stability analysis, passive component selection, and expected common-mode
EMI performance.
2.2 Setup
Figure 2-1 shows a typical EMI measurement setup. A line impedance stabilization network (LISN) in series with
each supply line and a good EMI receiver provide a measurement of the total EMI that includes DM and CM
propagation components. Appropriate addition or subtraction of the total noise measurement from each LISN,
designated as V and V
1 2
V
L 1
LISN
V
N
2
LISN
V = V – V
DM 1 2
V + V
1 2 LISNs are
V =
CM
2
bonded to the
GND plane
PE
Figure 2-1. EMI Measurement Setup for a Single-Phase System
4 Active EMI Filter Evaluation Module for Single-Phase AC Power Systems
to minimize the overall noise signature and required board area.
in Figure 2-1, enables an examination of CM and DM noise signatures, respectively.
EMI
receiver
i /2
CM
+
V
+
DM
–
i /2
CM
V
CM loop
CM
i
–
CM
Reference ground plane
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Note
for additional guidance pertaining to AEF circuit
Hot surface. Contact can cause burns. Do not touch.
High Voltage. Risk of electric shock.
Chassis
DM loop area
i
DM
EMI
filter
i
DM
Y caps
tied to
chassis
GND
CM loop area
SLVUCK7A – NOVEMBER 2022 – REVISED JULY 2023
TPSF12C1
CAUTION
CAUTION
AC/DC
switching
V
OUT+
regulator Load
V
OUT–
(EMI source)
The load may
V
SW
be floating or
tied to chassis
GND for safety
Chassis bonded
to the GND plane
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