One problem I see with non isolated capacitor-coupled PSU's is that if
a transient hits the line, then the capacitor will happily pass it..


At 09.50 2011.09.20, you wrote:
>> Yep.  Then note that there are two capacitors that bridge the
>> isolation boundary - treat them as being in parallel.
>
>In series, I think, in this context.
>
>_____________
>
>Added factor here is ratio of pump capacitor to floating store cap.
>Affects delta change which output can achieve per cycle. (Obvious but
>can cause issues in some applications). Here where a power supply is
>being created there is no problem. For using this as a FET gate drive
>the response time will be affected. (Again, obvious, but ...)
>________________
>
>The higher the pump frequency the lower that the capacitor sizes can
>be and the higher the achievable mains rejection.
>
>__________
>
>This circuit is useful for eg powering the simple digital panel meter
>IC's which demand that the IC float at the measuring voltage
>potential. Many such panel meters are offered for sale without enough
>information provided on how to power them.
>
>
>
>
>
>                 Russell
>
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