I'd use a DC - DC transformer to generate the +/- 300 volts.  (TY-79 
comes to mind.)
In the past I've used these Torroids to generate HV for Ham Radio 
applications from 12 VDC.
The transformer solution provides the isolation from the heater supply.
There are likely to be better transformers available today, the TY 
series is OLD...

BTW: I usually associate CRT anodes with MUCH higher voltages, could you 
have meant 3KV?

philpem@dsl.pipex.com wrote:

>Hi folks,
>  I'm trying to design a HV power supply to drive a DG7-32 CRT tube. I need the following outputs:
>    +6V AC/DC - heater supply. Isolated from everything else. 300mA minimum.
>    +400V DC  - deflection amplifiers
>    +300V DC  - CRT anode
>    -300V DC  - brightness and focus control
>    -200V DC  - cathode
>
>  Basically, what I want is something like the power supply circuit at <http://www.webx.dk/oz2cpu/clock-scope/scope.htm> but without the huge mains transformer. Ideally I want to run it off a 12V (or thereabouts) supply - i.e. a rechargeable battery pack (probably NiMH but equally likely a 14.4V 2AH Li-ion).
>
>  Does anyone have any suggestions? I was thinking of using a switchmode supply for the HV, but I haven't heard of any decent books or webpages that cover HV switcher design. Current requirements for the HVs are pretty meagre - less than 10mA total. The big problem is the 6V heater supply that needs to be isolated from (at the very least) the HVs.
>
>('scuse the "posted by Oakmailer" tag; I'm sending this through webmail and Oakmailer insists on tagging outbound mail)
>
>Thanks,
>Phil.
>
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>

-- 
  *
  |  __O    Thomas C. Sefranek   WA1RHP@ARRL.net
  |_-\<,_   Amateur Radio Operator: WA1RHP  
  (*)/ (*)  Bicycle mobile on 145.41, 448.625 MHz

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