buck converter using LM3477A

[reiniheini]

Hi there,

i built an dc-dc converter using a LM3477A.
In generous I used the components similar to that which are mentoned in the datasheet application.
The main difference in my design is that the output voltage should be adjustable.

But murphys law means: Everything else is swinging but not an oscilator. (or so)
So my circuit too!

The gate driving voltage is an quite ideal rectangle wave.
But the current/voltage of the sense resistor swings at very high frequency.
I double checked my circuit ad variated different parts.
But I can not determine where it comes from.

Please let me know if somebody has an idea!

Thanks in advance.

Regards
reiniheini

 

[IanP]

One picture is sometimes better than one million words ..
Would you be able to post the circuit diagram?