Re: SMPS inverter voltage feedback methods

MooseFET wrote:
On Jan 27, 4:09 pm, Terry Given <my_n...@xxxxxxxx> wrote:
Joerg wrote:
MooseFET wrote:
[...]
To monitor the waveform? Why not just sample it? Send sampling pulse
through toroid xfmr,
[....]

I cant quite picture it, would you care to cough up an ascii schematic?
didnt unitrode make a chipset that did prettty much this?
Here's what was rattling through my mind while I was thinking about
how to do this.



ACFB+ ! ! ACFB-
+-/\/\--+
! !
(((((((
=======
(((((((
! ! !
! -- ! ---------+--/\/\/---- +Vout
! ! !
!/ \! \
!! ----------! !---- /
Drive ---- !! ( !\e e/! ! \
) !! ( ! ! ! !
) !! ------------+-------+----- ! --+----------- -Vout
) !! ( !
GND ------ !! ( !
!! ---------------------------


This works even in the AC case if the resistors bring the voltage low
enough that the EB junctions aren't breaking down while the
transistors trade off conducting.


Hi,

I put this schematic into ltspice and it seems to kind of work, the AC
voltage is being chopped by the Drive signal to Vout, but it is 90
degrees out of phase with the input AC signal, and also very low
amplitude. Any ideas how to get the output phase to match the AC input?

Heres the circuit and waveform:

http://rocketresearch.nekrom.com/new/transformer%20chopper%20voltage%20measurement/circuit1.jpg
http://rocketresearch.nekrom.com/new/transformer%20chopper%20voltage%20measurement/waveform1.jpg

ltspice file:
http://rocketresearch.nekrom.com/new/transformer%20chopper%20voltage%20measurement/circuit1.asc

cheers,
Jamie
.