High voltage boost circuit

For the Dutchforce Electronics Forum / Weekly Electronics Challenge.

The challenge is to convert a supply of about 15V or less to as high a voltage as possible, using a single stage boost converter. This circuit goes right up to the transistor's limit, which is pretty accurately 800V as rated.

Schematic:
http://myweb.msoe.edu/williamstm/Images/Boost1.jpg
Picture:
http://myweb.msoe.edu/williamstm/Images/Boost2.jpg

Category:

Science & Technology

Tags:

• electronics
• boost
• converter
• high
• voltage
• switching
• supply

[xenarian]

I'm trying to do something very similar. I've got a 12v battery I'm trying to switch up to 600v or so; I guess I could also use my bench power supply as you did.

How did you calculate your inductance needed? It looks like you've got about 25 turns of 20AWG around a toilet paper roll. How did you decide on this particular value?

[T3sl4]

@xenarian The inductance is not critical in this example because the frequency and duty cycle are variable. For 600V at low current, I would recommend a flyback converter, rather than boost. Ridiculously high ratios such as these are only of academic interest, because the transistor ratings required increase astronomically with both output power and voltage ratio. Better to use a transformer to achieve the ratio, so your duty cycle is more reasonable (around 50%, ideally, not like ~95% here).

[T3sl4]

Sure, but keep in mind it's voltage mode (no short circuit protection -- dangerous), open loop (no regulation), and low efficiency due to the high voltage ratio / lack of secondary winding.

Added links to the description.

[barryforever]

could you post any links to your circuitry , Im trying to work one like this