Browse Prior Art Database

Diagnostic Device for Conducted Noise Emissions

IP.com Disclosure Number: IPCOM000061217D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Hardin, KB: AUTHOR [+2]

Abstract

A device is attached directly to phase and neutral outputs of a line impedance stabilization network (LISN) to enable separate viewing with a spectrum analyzer of differential and common-mode components of a power supply filter to indicate which component is dominant. This indication of the dominant component of the power supply filter enables changes to be made to cause a reduction in the total conducted noise emission. A power supply 1 (Fig. 1) is connected through a power supply filter 2 to an LISN 3. A device 4 is connected between the LISN 3 and a spectrum analyzer 5 to enable the spectrum analyzer 5 to determine whether a common-mode current (ICM) or a differential-mode current (IDM) is dominant. IDM flows out of the filter 2 on a phase conductor 6 (Fig. 2) and returns on a neutral conductor 7.

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Diagnostic Device for Conducted Noise Emissions

A device is attached directly to phase and neutral outputs of a line impedance stabilization network (LISN) to enable separate viewing with a spectrum analyzer of differential and common-mode components of a power supply filter to indicate which component is dominant. This indication of the dominant component of the power supply filter enables changes to be made to cause a reduction in the total conducted noise emission. A power supply 1 (Fig. 1) is connected through a power supply filter 2 to an LISN 3. A device 4 is connected between the LISN 3 and a spectrum analyzer 5 to enable the spectrum analyzer 5 to determine whether a common-mode current (ICM) or a differential-mode current (IDM) is dominant. IDM flows out of the filter 2 on a phase conductor 6 (Fig. 2) and returns on a neutral conductor 7. ICM flows out of the filter 2 on each of the conductors 6 and 7 and returns on a ground conductor 8. Capacitors 9 and 10 are intended to affect only noise produced by IDM. Capacitors 11-14 and a common choke, which comprises coils 15 and 16, are intended to affect only noise produced by ICM. If noise produced by ICM is dominant for a specific product, changing the values and/or placements of the capacitors 9 and 10 would have little effect on the total noise emissions. If noise produced by IDM is dominant, changing the values and/or placements of the capacitors 11-14 or the choke would have little effect on the total no...