Hi all,

on my journey to try and create my 12 to 24V boost converter from scratch I've followed these equations (http://www.ti.com/lit/an/slva372c/slva372c.pdf) to come up with the circuit attached and as you can see it doesn't really boost anything (+11.16V relative to ground)

In Falstad I seem to get an oscillating voltage between +20V and +11V.

I feel like there's something basic I'm not getting and any help would be helpful to get a better start at this.

 

hi CD,
Use a MOSFET capable of switching ON 'hard' with a 5V Gate voltage.
This circuit works, but it is not optimised for best performance, but it should help in your design.
E

 

See

 

I feel like there's something basic I'm not getting

V1 is not connected to ground! Add a ground symbol to the bottom of V1.
V1 Von=5V which is a little small for most MOSFETs. Change to Von=10V
I changed to a real MOSFET. (pick anyone from the list, 50V)

 

V1 Von=5V which is a little small for most MOSFETs. Change to Von=10V
I changed to a real MOSFET. (pick anyone from the list, 50V)

Thanks, I read in another thread that LTSpice can have unexpected behavior on default components. And Thanks @ericgibbs, makes sense. Also thanks @Bordodynov, still learning the commands with LTspice but your curves make much more sense.

@ronsimpson, your note about ground connection pushed me to experiment in Falstad and I have a question I'll be posting in a new thread.