Filter Cap Directly from Rail to Rail, excluding Center Tap

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What is the disadvantage associated with implementing the Filter Capacitor directly from rail to rail , excluding Center Tap which is usually Ground.......
This thought came into my mind while preparing to design a SMPS for Class-D amp........

Apart from High Voltage Rating of Capacitor, which is the other thing to be taken into consideration
 

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Hi

The disadvantage is that your ground impedance will be dictated by whatever the center tap is made of: batteries in your example, which may be aceptable. If you try the same trick with a transformer + diodes, you'll get some nasty surprises: during the blocking periods of the diodes, the center tap will be left floating, and therefore pretty useless for most applications.
LV
 
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Workhorse said:
What is the disadvantage associated with implementing the Filter Capacitor directly from rail to rail , excluding Center Tap which is usually Ground.......

Is this for a single ended or bridged output stage? High currents flow between the supply rails in a bridged design and between each rail and ground in a single ended design.
 
Re: Re: Filter Cap Directly from Rail to Rail, excluding Center Tap

BWRX said:


Is this for a single ended or bridged output stage? High currents flow between the supply rails in a bridged design and between each rail and ground in a single ended design.

Its for the Half Bridge Class-D amp....so i think Split capacitor is mandatory!!
 
Workhorse said:
What is the disadvantage associated with implementing the Filter Capacitor directly from rail to rail , excluding Center Tap which is usually Ground.......
This thought came into my mind while preparing to design a SMPS for Class-D amp........

Apart from High Voltage Rating of Capacitor, which is the other thing to be taken into consideration


i have done this on atx psu's that had half-bridge topology, whereas there were two 220ufd/200volt caps in series, i added a 470ufd/450 volt cap across and the power supply seemed to be able to deliver more evidenced by the pc's being overclocked, wheras before it could not.

:D

haven't tried it on an amp though...
 
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