This post asked a similar question to mine, but the problems that I have noticed are distinctly different.
I have a PCB that uses a buck converter to supply 12V from a 24V source, and I am boosting the 12V to 36V. The boost converter works well on its own from a power supply's 12V (150mA), but only outputs 12V (4.32mA) when supplied with the output of the buck converter.
Why might the boost converter be working incorrectly when supplied from the buck converter?
The buck converter should be able to supply up to 3A, and when a 68 Ohm resistor is connected 170mA are seen through the resistor.
When a 1 Ohm resistor is put between the converters, the characteristics worsen - more current drawn, output voltage of boost converter reduced.
I'm sure that the 24V source would have been sufficient to boost to 36V but no appropriate parts were found for this function.
Are there any other investigative steps I should make to ascertain the source of the issue?
The buck converter is connected as seen in the following schematic, where Vin is 24V.
The boost converter is connected using Cin=220uF, Cout=100uF, Ctune=10nF, Rtune=30.1kOhm, Rtrim=6.98kOhm