Empty Capacitor Bank

In what way is it not working ?

MK

I am not sure what exactly is going on, the Light Emiting Diode is not lighting, therefor the circuit is not complete. I have everything in the correct places and the circuit made, nothing is working...

I am not sure what exactly is going on, the Light Emiting Diode is not lighting, therefor the circuit is not complete. I have everything in the correct places and the circuit made, nothing is working...

It looks like the LED should only come on after the high voltage is reached - which could take a long time - depending on how big the capacitor bank is.

The IRF540 is only rated for 100 volts - I don't see how this circuit can generate 500 volts without damaging the IRF540.

What voltage is on each pin of the 555?

Please take time to fully understand your entire rig, including ratings and tolerances on all high voltage parts - this circuit can have dangerous voltages and energy.

IRFP450 is rated 500V (VDS) in Vishay data sheet so should be OK.

@Conor - do you have any test gear (DMM, Scope)  - no point suggesting measurements you cant do.

Have you tried simulating this circuit - you can get  a free simulator from Linear technology and it will show you the kind of waveforms to expect.

Can you post a picture of your prototype.

MK

Did some quick simulating myself - it's not a good ciruit - the boost factor is affected by the mark/space ratio of the 555 output so you can't get a very high voltage with the 4k7 and 15k values. If you reduce the 15k you can get more boost but the lack of current control in the FET means that you will get very large start up currents.

How many volts do you want on the big capacitor and what value is it ?

MK

I have 4 400 volt 47uF capacitors that my bank consists of. In replacement of the 10uF capacitor, I have a 1nF capacitor, That could be part of my problem too...

1nF 50V Capacitor as a place filler for the 10uF

There is no 10uF cap, just a 10nF on the original scheamatic.

I've made (simulated)  a version that works - without any silly currents anywhere. I've used the nearest bits in LTSpice that would work, the comaprator and MOSFET you have should be OK. Not sure about your diode because you don't give  a proper part number.

I've reduced the cap to 4.7uF to speed up the simulation - with 4 x 47 it will take 40x as long to charge up, ie about 4 seconds. The 4.7 ohms resistor limits the current in the FET, crude but simple, needs to be rated for 10W, will get hot. L1 must be able to take 4A without saturating.

If you want to do this kind of stuff then download LTSPice and learn how to use it - much cheaper than buying bits and frying them.

Finally:

TAKE CARE - 188uF @ 400V CAN EASILY KILL YOU !!

MK

Thank you so much for your help! I will change up what I have test it. I'll let you know if it works or not.

Does the LM311 work the same as the LT1011?

It should work the same but it has better specifications, so if some marginal design depends on poor performance, this part might perform too well..