I'm designing a powerboard which needs multiple positive and negative output levels. In such I need a +-40V output.
Therefore I used a setup which first generates a stable 12V input (by using http://www.ti.com/lit/ds/symlink/lm1085.pdf, verified 12V stable level) going into a lt3463, which is designed as the second example of Design Note 359.
First to be sure: I'm not entirely sure if this topology is the inverting charge pump regulator, yet if I read the specs voltage in this design example outreaches the max voltage at pin SW2 (42V) so inverting charge pump design is suggested. As I don't see any inductor in the output stage I'm guessing this should be the inverting charge pump topology, correct?
My design would otherwise put 52V at SW2 pin, which would kill it ofcourse.
Now I get the positive side of the output (+40V) yet my output stays around 0V (some mVs, so guessing multimeter error). All connections have been verified and I tried swapping even all components which influence the negative side of the LT3463.
When checking the internal diode (D2) I get a reading of approx. 0.7V so seems correct functioning.
SW1 as well as SW2 measure approx 50Ohms to ground.
shdn1 & sdhn2 are tied high (at the 12V input).
All resistors, input inductors and schottky diode are chosen equally as in the design paper. Output caps I did choose larger, 0.47uF instead of 0.22uF but shouldn't have influence.
Is there any way to verify where it's going wrong if not for the design?
In attach my LTSPICE file and a picture of eagle layout of this part.