TPSF12C3 Active EMI Filter (AEF)

Texas Instruments' TPSF12C3 is an active filter IC that is designed to reduce common-mode (CM) electromagnetic interference (EMI) in three-phase AC power systems.

The AEF is configured with voltage sense and the current inject (VSCI) uses a capacitive multiplier circuit to emulate the Y-capacitors in a conventional passive filter design. The device senses the high-frequency noise on each power line using a set of sense capacitors and injects noise-canceling currents back into the power lines using an injection capacitor. The effective active capacitance is set by the circuit gain and the injection capacitance. The AEF sensing and injection impedances use relatively low capacitance values with small component footprints. The device includes integrated filtering, compensation, protection circuitry, and an enable input.

The TPSF12C3 provides a very low impedance path for CM noise in the frequency range of interest for EMI measurement. Enabling up to 30 dB of CM noise reduction at the lower end of specified frequency ranges significantly reduces the size, weight, and cost of the CM filter implementation.