0-300V DC signal generator

impedances.

by

converter.

Our machines at work use a fullwave CW multiplier and at ~ 7k volt ,100khz at the input, we can get over 2Mvolts at the other end.

We use a litz pie stack transformer to obtain the split phase at the start of the CW chain.

Jamie

i've made something close to that.. I didn't need to supply the actual power supply but I did make the control amplifier output..

The requirement was to have up to 1 amp of current at 350VDC max and be able to proportionally control it. I guess the supplied HV DC varied with some other settings on another piece of equipment and the control point here needed to set the 0..100% scale of what ever was coming in at the HV terminals.

So what I did was use a complementary HV output bjts with a HV pair of small signal transistors to form a differential circuit as a feed back to maintain output.

This was optically coupled and PWM driven to the HV side where I formed a clean 0..100% DC signal to inject into one side of the differential circuit and the other side, like I said was of the feed back.

Input side had a PWN generator via an analog 0..10V.

I experimented with different base frequencies because they needed a minimum response time that had to be met.

I have assembled and sold 11 of these so far.. Not bad for a home base side job..

Don't ask me exactly what it was they were using these for because I couldn't get that information out of them. This was being install by a hired contractor that was updating equipment as a needed item. The control point was coming from a PLC.

Jamie

Well you could take off the shelf wall wart flyback transformer and use it backwards, but this looks like overkill for what you doing.

A multiplier should do just fine for 1ma of current.

Vladimir Vassilevsky DSP and Mixed Signal Designs

Il 05/05/2013 21:33, Tim Wescott ha scritto:

Well, let's call it an "amplifier".

I have no other details, until now. Perhaps it will be a piezo-electric actuator but they just asks me some ideas to "generate a DC voltage between 0 and 300V with a max current of 1 mA". That's all for now.

I would like to know those requirements too. I don't know they at the moment.

Interesting, thanks Marco

Oh boy! Six months from now when your slow, power efficient 300VDC supply won't drive their actuator at 1000Hz they'll have you hanging by your thumbs for not knowing how to design circuits.

Or, six months from now when your fast, big, hot, 300V, 10kHz bandwidth amplifier is working perfectly, they'll hang you by your thumbs for gilding the lily.

Either way, you'll feel like a Real Engineer.

I think that it controls something rather than powers it is the correct question. Since control is the goal, the task statement is to take a DAC signal and amplify it to 0 to 300 V with a mA or so of current capability all from a 24 V power rail. No?

?-)

and

You may be on to something here. Use 3 or 4 MSB to control the "higher voltage" generator in say 50 or 25 volt steps and a series and shunt regulator to provide the resolution, two quadrants and speed.

?-)

That's what I was doing some 55 years ago ;-) ...Jim Thompson

Il 11/05/2013 05:25, josephkk ha scritto:

The DAC is not mandatory. I'm trying to make an isolated flyback with an LT3748. I will change the output voltage changing the feedback resistor using an i2c digital potentiometer.

Marco

This uses an ISDN transformer and a doubler to make about +120 volts. Q4 is a current limiter, about 1 mA, and then it's shunt regulated by the zener stack.

That IR half-bridge driver is spiffy.

The Brat did the board layout...

is a

tack.

They have similar 100V driver that goes to 500KHz and has 1A gate drive: ir2085 not pin compatible though

-Lasse

stack.

That one must be speffy.

From the estimable Steve Roberts, who is off installing a fancy laser someplace exotic where his data plan doesn't work:

"Send Marco to Emco high voltage. They make what he needs off the shelf."

Cheers

Phil Hobbs

Wow, a 600V bootstrapped half-bridge 555 timer. Obviously a 'legacy part' that nobody ought to be using if they had the intelligence of a patch of blue-green algae. ;)

Cheers

Phil Hobbs

Il 11/05/2013 19:12, Phil Hobbs ha scritto:

He's right! Thank you (and him) very much, I'm reading through their products datasheets.

Marco

stack.

The IRS thing is a nice part. It has a shunt-regulated power supply, oscillator, anti-shoot-through timing, and the highside and lowside gate drivers. SO8, 90 cents.

Marco Trapanese wrote in news:kmlef7$eae$ snipped-for-privacy@tdi.cu.mi.it:

Now explain the difference between a DAC and a i2c digital potentiometer. As far as I know , there is no difference.

snipped-for-privacy@tdi.cu.mi.it:

a DAC generally has a variable voltage or current output, a digital potentiometer a variable resistance. I'd say there's quite a difference

-Lasse

That will change the loop gain and dynamics.