Patrick...
A few comments
- You need a connection from the 10/25W safety resistor to chassis ground.
- I like to put the HV sense on the PA rather than in the Power supply and
feed a sample of the
HV back to the protection circuit...because it protects the PA if I forget to
connect the HV lead.
- Suggest two resistors in parallel for R19. This prevents a fail/open of
one resistor from
letting HV get on the HV measure line.
- If you want to use isolated HV current sense with the 4N33, put MOV's on
the Ifault lines to
prevent HV getting into the logic if there's a fault.
- Cut out a slot in the PCB under the 4N33 to provide a longer sneak path
for HV.
- You can also put the Ipa current fault in the return line and avoid the HV
issue. Ian GM3SEK
describes this well in his TCB manual,
http://www.ifwtech.co.uk/g3sek/boards/triode/triode-manual.pdf
- But then you might want to use a lower value series resistor. Take a
look at
http://wa1hco.net/uTCB/uTCB_sch.pdf for an idea. R21 and R21 in parallel make
a 0.5 ohm sense
resistor in the HV return line. R17-R20 add an offset to move the sense
voltage into the positive
region. The PSOC chip has an op-amp to measure the small drop across the
resistor.
- I've had problems with step start circuits and large relays because they
draw too much current
and require a high power dropping resistor and vary large capacitor value to
get enough RC time
constant. You might consider using a small relay with high coil resistance to
drive the relay that
shorts the step start resistor.
hope this helps...
jeff, wa1hco
Patrick Egloff wrote:
> Hi all,
>
> I'm back in the "business" after several very busy months and i'm continuing
> my 2m amplifier project. (4CX1500B)
> I'm still collecting parts and i will start with the power supplies.
>
> I made a diagram of my HV supply and i'ld be happy if you could look on it
> and say if everything seems OK.
>
> I added :
> - step-start
> - glitch protection
> - current overload detection
> - voltage lack detection
> - current measure
> - voltage measure (both with external meters)
>
> I used the components i've actualy found. For example, the K1 ON/OFF relay
> could better be a DPST instead of a SPST...
>
> The diagram can be seen here :
> http://tk5ep.free.fr/tech/PA2m/datas/HV%20supply.gif
>
> Any comments are welcome.
>
> 73 and a very happy new year to all readers,
> Patrick
>
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