Texas Instruments Corporation

Yongbin Chu

Yogesh Kumar Ramadass

Jeffrey Anthony Morroni

Saurav Bandyopadhyay

Vijaylaxmi Gumaste Khanolkar

Zhemin Zhang

Robert Martinez

Todd Allen Toporski

In some examples, a circuit includes an amplifier, a resistor, and a damping network. The amplifier has an amplifier output and first and second amplifier inputs. The first amplifier input is adapted to be coupled to a first terminal, and the second amplifier input is configured to receive a reference voltage. The resistor is coupled between the amplifier output and the first amplifier input. The damping network is coupled between the amplifier output and the first terminal.

Active electromagnetic interference filter with damping network

An active electromagnetic interference (EMI) filter includes a first amplifier and a second amplifier. The first amplifier is configured to sense noise signals on a power conductor. The second amplifier is coupled to the first amplifier and is configured to drive a cancellation signal onto the power conductor. The cancellation signal is to reduce the amplitude of the noise signals sensed by the first amplifier. An output impedance of the second amplifier is lower than an output impedance of the first amplifier.

Cascaded active electro-magnetic interference filter

A packaged electronic device includes first conductive leads and second conductive leads at least partially exposed to an exterior of a package structure, and a multilevel lamination structure in the package structure. The multilevel lamination structure includes a first patterned conductive feature having multiple turns in a first level to form a first winding coupled to at least one of the first conductive leads in a first circuit, a second patterned conductive feature having multiple turns in a different level to form a second winding coupled to at least one of the second conductive leads in a second circuit isolated from the first circuit, and a conductive shield trace having multiple turns in a second level spaced apart from and between the first patterned conductive feature and the second patterned conductive feature, the conductive shield trace coupled in the first circuit.

Isolated transformer with integrated shield topology for reduced EMI

In described examples, a system (e.g., a light-emitting diode dimmer system) includes a switching device coupled to a switching controller. The switching controller generates a control signal, which includes a low frequency signal (e.g., for controlling a dimming function) and a switching signal. An active electromagnetic interference filter (AEF) is coupled to the DC source. An active shunt is coupled to a power input node of the switching device and is configured to selectively couple a shunt current to the power input node of the switching device in synchronization with the low frequency signal (e.g., which can reduce, if not also eliminate, a saturation time of the AEF and improve the performance of the AEF).

Active shunt filtering

An active electromagnetic interference (EMI) filter includes an amplifier configured to sense noise signals on a power conductor, and drive a cancellation signal onto the power conductor. The cancellation signal is to reduce the amplitude of the noise signals. Some embodiments of the active EMI filter include a high frequency compensation network that improves the high frequency phase margin of the active EMI filter and improves the stability of the active EMI filter at high frequencies. Some embodiments of the active EMI filter include a low frequency compensation capacitor that increases the phase margin of the active EMI filter at low frequencies. Some embodiments of the active EMI filter include low frequency compensation circuitry that increases the low frequency tolerance of the active EMI filter.

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Plano, TX, United States of America

Yongbin Chu