lm393 regulator works without switching?

[jrshedden]

Hi All,

I've attached a circuit that should be a switching regulator. I see regulation, but I don't see any switching going on during interactive simulation.

Thanks in Advance for any help. My Multisim skills haven't been used in some time, and I could use a boost.

Regards,

Jim S.

[Tayyab_R]

Hi,

I think you should double check the circuit as I see a comparator for which no output is connected. This could be why it is not swithching.

Hope this helps.

[jrshedden]

Hi Tayyab,

Thanks for having a look and taking the time to reply.

I did have another look at the schematic and I think it is correct. The comparator without the output connected  is not used in the circuit. It is there because it has the power connections and should be properly tied at the inputs to avoid oscillation. I probably should have used that one first and left the other one out of the picture. It's been a long time, so maybe I was using it and stopped.

Regards,

Jim Shedden