[Elecraft] KPA500 Curiosity Question

[hawley, charles j jr]

The 270 volts is bias for the pin diode switching. It’s generated with a voltage triplet off the 60 volt supply transformer.

Chuck KE9UW
c-hawley at illinois.edu

Sent from my iPad

> On Mar 22, 2018, at 11:24 AM, Phil Hystad <phystad at mac.com> wrote:
> 
> Is there a published circuit diagram of the KPA500, in particular the power supply?  I was curious about the design of the power supply and had a few questions.  Note:  these are motivated merely by my curiosity and interest.  I have no real need to know.
> 
> For example, the KPA500 shows a block diagram of the amplifier & power supply and one of the voltage outputs is +270 and I was wondering what part of the amp circuit needs 270 volts, or 60 volts for that matter.
> 
> In idle mode, the HV display on my KPA500 reads 71 volts.  Thus, not 60 and not 270 volts.
> 
> Another question -- the other voltages from the supply are +5, -12, and +12.  I assume these are regulated voltages.  But, is the +60 and +270 regulated?  If these are regulated, what kind of voltage regulator is used.  I am likely ignorant and even possibly naive in this area as I have only used low-voltage regulator chips and so do not even know if HV regulator chips even exist (would they be stacked devices?).
> 
> End of questions for now.  Yes, a circuit diagram would answer all my questions.
> 
> 73, phil, K7PEH
> 
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