high voltage switch mode power supplies

[tillu]

Hi all,

what are the various techniques that one can use for making high voltage (4kV/7 mA) dc switch mode power supplies. anything specific about fly back scheme used here. also suggest me some vendors who can provide high voltage fast recovery diodes for this application. here i am not intrested in using any multiplier stage.

Thanks and Regards,

 

[v_c]

Take a look at the application notes at Texas Instruments (http://www.ti.com) and international rectifier (http://www.irf.com). IR will have the MOSFETs and diodes that you need whereas TI is mostly for control ICs. You can also look at the notes from ON semiconductor (http://www.onsemi.com), they have both the control IC and the devices.

Best regards,
v_c

P.S. If this is for a Laser power supply -- I suggest you check out http://www.repairfaq.org/sam/laseraps.htm

 

[nlulani]

the general technique that i have come accross for the power supply of the kind you are stating is as follows: -
a buck regulator based low voltage power supply which is followed by a chopper and multiplier section. here the adavnatge is that you can use 1 kV fast recoverry diodes which are cheaply avalable.
be specific about the ripple and regulation(load and line).

 

[jodokus]

Diodes for this purpose are made by EDI and VMI. The topology that I know of is a transistor based harmonic oscillator that drives a tranformer. With miniature transformers (ER9.5 shape) one can reach approx. 1000Vpp. this is followed by the neede number of multipliers. I anyone kwows a more efficient method or knows about othe brands of diodes I am interested.

 

[vdaniel]

There are different possibilities to build such HV converter, but the most problematic part is the high voltage transformer. If you find a standard transformer, you can then implement the converter architecture according to it.
For example for power up to 6W and voltage up to 3kV one can use standard transformers from, say, Coilcraft, for Cold Cathode luminescent lamps, used in LCD displays. Accordingly the schematic of the converter is current-driven push-pull resonance conveter.
Varuzhan