Jim said:
What do you mean by "reverse" voltage? Opposite of normal operation?
If so, as soon as you pass thru zero **collector-base** it will start
to forward conduct just like a diode. Depending on what's happening
at the base in your circuit you can get inverse PNP action.
You might want to limit the impedance on the base (to avoid the diode
clamp to OV), so that Vce can go negative without clamping. For example,
in driving a push-pull centre taped transformer. You might want one side
to spike up to 2*Vcc + Vclamp, whence the other side will want to go
to -Vclamp, i.e. a reverse voltage. This is to allow for an extra
voltage to reset the core duing dead time to eliminate flux imbalance.
Kevin Aylward
[email protected]
http://www.anasoft.co.uk
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