Hi everyone, hope you’re surviving the coldness of winter °3°
Today i will talk about a concept that I’ve built a few month ago about voltage conversion.
I was in the need of an high voltage source but could only afford a low voltage supply. In the field of well-known High Voltage converters there are a bunch of heavy transformer, expensive DC Boost converters (but very stable and with a good current supply) and pure Voltage multipliers.
Finally, I’ve chose the third option (In the end, I’ve mainly combined the two last options..) which is designed for simple a DC DC Conversion, exactly what i want.
For example, the main schematic for a “Dickson Bridge” works like this :
It’s an multiplier bridge that you can (quite) extend at will . That voltage multiplier do the job by adding the voltage supply value at each step.
For example, if you bring a 5 volts supply with 5v-Ov complementary oscillations on a 4 step bridge you will have 20 volts on the output :
An easy what to manage the oscillation and make them complementary is an “Astable” oscill. like the NE555 with two OP-Amp on the output.
The first OP-Amp will have Vcc/2 on the “+” and the second one on the “-“, so when the square-wave comes they will react in a complementary way.
As always , we can search for new ways of using this concept !
For example, the two OP-amp could have an 5v-0v in input (with the 5v/2 comparator-limit) BUT be supplied in 40v – 0v. That will produce a medium voltage oscillation (38v-2v [because an comparator output equals approx Vsupply – 0v]) that can manage a 40v bridge-supply with only a single 5v input (be careful of the Slow Rate !) .
It allows you to keep you’re (5v) NE555 for your wave-generation instead of building a complex high voltage oscillator.
With a x4 Dickson Bridge it will bring 160v (approx.) on the output !
But keep in mind that the system is not a current supply so don’t expect much more than 10mA (depends of the capacitor)
Also, if you put a resistor on the output, the output-capacitor will discharge in it, so you need to have a good value for your capacitor and a good frequency oscillation if you don’t want to have spikes instead of a flat DC output (but in involve less multiplication step because the system is slower !).
Hope that gives you some ideas !