Re: 600V supply (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Wed, 21 Jul 2004 08:53:51 +1200
From: Malcolm Watts <m.j.watts@xxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: 600V supply (fwd)

On 20 Jul 2004, at 14:21, High Voltage list wrote:

> Original poster: Steven Roys <sroys@xxxxxxxx>
>
>
>
> ---------- Forwarded message ----------
> Date: Tue, 20 Jul 2004 10:42:40 -0600
> From: Hydrogen18 <hydrogen18@xxxxxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: Re: 600V supply (fwd)
>
> Tom,
> full bridge rectify a dispoable camera flash, and put a couple of
> series electrolytic caps from switching power supplies on the output.
> Should charge up to around 600 VDC

Unfortunately not. The inverter in the cameras is a forward type with
output proportional to the turns ratio - i.e. it is largely pegged by
the battery voltage. Since the camera normally charges a (fairly
hefty already) capacitor to around 300 VDC a better option might be
to remove the existing capacitor and replace it with a voltage
doubler if the circuit configuration allows it. I say this because in
a lot of these designs, correct inverter operation is dependent on a
heavy capacitive load on the the output and a common configuration
actually relies on pushing capacitor charging current through the
base of the switching transistor.

Malcolm