[Amps] My HV supply design.

[jeff millar]

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
>