Cascaded active electro-magnetic interference filter
AssigneeTexas Instruments Incorporated
InventorsYongbin CHU, Yogesh RAMADASS, Saurav BANDYOPADHYAY, Todd Allen TOPORSKI, Jeffrey Anthony MORRONI
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Abstract
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.
Claims20
An active feedback electromagnetic interference (EMI) filter, comprising:
- a first amplifier coupled to a power conductor at a first node;
- and
- a second amplifier coupled to the first amplifier and the power conductor, wherein the output of the second amplifier is coupled to the first node and an output impedance of the second amplifier is lower than an output impedance of the first amplifier.
An electromagnetic interference (EMI) filter, comprising:
- a sense amplifier configured to:
- sense noise on a power conductor;
- and
- generate, based on sensed noise, a cancellation signal to counteract the sensed noise;
- and
- an injection amplifier coupled to the sense amplifier and configured to inject the cancellation signal onto the power conductor;
- wherein an output impedance of the injection amplifier is lower than an output impedance of the sense amplifier.
A switch mode power supply, comprising:
- a switching DC-DC converter configured to convert an input voltage to an output voltage, wherein the switching DC-DC converter receives the input voltage via a power conductor;
- an active electromagnetic interference (EMI) filter coupled to the power conductor, the active EMI filter comprising:
- a sense amplifier configured to:
- sense noise on the power conductor;
- and
- generate, based on sensed noise, a cancellation signal to counteract the sensed noise;
- and
- an injection amplifier coupled to the sense amplifier, the injection amplifier configured to inject the cancellation signal onto the power conductor;
- wherein an output impedance of the injection amplifier is lower than an output impedance of the sense amplifier.
Dependencies are inferred from the claim text.