T
Tim Williams
- Jan 1, 1970
- 0
Now, on a switching supply, you're supposed to have a Y-type cap between
input and output commons, to shunt the RFI coupled across the transformer's
interwinding capacitance (and maybe a common mode choke on input and/or
output to improve that isolation with respect to the surroundings). But
what should you do if the output side is also bouncing (different frequency,
out of phase)?
Specifically, imagine a high side gate drive circuit powered by a DC-DC
converter. The driver's "common" is bouncing at, let's say 320Vp-p, so it's
not really "common" in any useful sense. What then? Should there be CM
chokes anywhere, or would those only make things worse (e.g., resonating
with the parasitic capacitances)?
Tim
input and output commons, to shunt the RFI coupled across the transformer's
interwinding capacitance (and maybe a common mode choke on input and/or
output to improve that isolation with respect to the surroundings). But
what should you do if the output side is also bouncing (different frequency,
out of phase)?
Specifically, imagine a high side gate drive circuit powered by a DC-DC
converter. The driver's "common" is bouncing at, let's say 320Vp-p, so it's
not really "common" in any useful sense. What then? Should there be CM
chokes anywhere, or would those only make things worse (e.g., resonating
with the parasitic capacitances)?
Tim