Feedback Buck SMPS - with Integrator

389

05:32:40

Close the switch to start the circuit.

Based on...
 http://everycircuit.com/circuit/5419355125579776

...but with the addition of an intergrator into the control loop. 

The "ground" for the control loop is now 5v to allow inverting amps required for integrator to run on a single 12v supply.

Comments and suggestions welcome.

published 6 years ago

PrathikP

6 years ago

I haven't checked your control circuit, but your basic buck converter is wrong. It's missing a freewheeling diode. And the inductor have no effect. An appropriate value would be 100uH. The capacitor is too big. An appropriate value would be 470uF. Ofcourse, these values depend on switching frequency, input/output voltage and load current.

mlira

6 years ago

Thanks for your comment, the diode and inductor are that way because EC falls over if I change it and I was mainly looking at the control side. If you know of a way to get it working properly please let me know. I need to draw ~50a and don't really want to run higher than 20kHz (my scope only runs at 1MHz), so the cap bank needs to be fairly big for my needs and I'm not sure if 470uF will be enough to keep the ripple low enough.

PrathikP

6 years ago

I didnt know you wanted to draw 50A. So for such high currents, you cannot use a simple asynchronous buck converter. You will need a multiphase synchronous buck converter, with is difficult to build (as you can tell from the name of it).

PrathikP

6 years ago

And a 1nH inductor is as good as nothing

fatcat2

6 years ago

What about the control circuitry?

PrathikP

6 years ago

Ofcourse, the control circuit has to be designed accordingly. It's far more complex.

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