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I am looking how to minimize switching interference on an smps that is powering an AB class amplifier.
Measuring at the amplifier output there is about 0.8 to 1v parasitic high frequency oscillation, then measuring on the DC supply rails there is also a parasitic ripple around 0.8v amplitude, I cannot read the waveform exactly (my older scope can't focus on very spikey waveforms) but they appear to be small very "sharp" spikes seemingly at or near the switching frequency of the smps (around 50 Khz)
I already have ceramics parallel to secondary filter caps , also snubbers across the secondary DC output.I tried wrapping the DC output wires that supply the amp around a ferrite choke, toroidal ferrite two turns per core. This seems to remedy the situation a little by "rounding" the spikes into a bit lower amplitude sine-like oscillations at the amp output, audibly it help by almost eliminating the sharp crackling noise but still the scope shows an ugly output.
I wonder how to design a choke that can deal with such spikes as best as possible?
Any advice is welcome.
thanks.
Measuring at the amplifier output there is about 0.8 to 1v parasitic high frequency oscillation, then measuring on the DC supply rails there is also a parasitic ripple around 0.8v amplitude, I cannot read the waveform exactly (my older scope can't focus on very spikey waveforms) but they appear to be small very "sharp" spikes seemingly at or near the switching frequency of the smps (around 50 Khz)
I already have ceramics parallel to secondary filter caps , also snubbers across the secondary DC output.I tried wrapping the DC output wires that supply the amp around a ferrite choke, toroidal ferrite two turns per core. This seems to remedy the situation a little by "rounding" the spikes into a bit lower amplitude sine-like oscillations at the amp output, audibly it help by almost eliminating the sharp crackling noise but still the scope shows an ugly output.
I wonder how to design a choke that can deal with such spikes as best as possible?
Any advice is welcome.
thanks.