Is there any problem if we leave one of the secondaries in a flyback converter floating?
I have two secondaries: 24V & 18V. My application needs only 24V. What happens if the 18V winding is left floating?
Electronic – ny problem if one of secondary windings is left floating in a flyback converter
flyback
Related Solutions
There may be a couple of things wrong in your picture: -
Firstly, the diode maybe the wrong way round if you are expecting a positive output and secondly the phasing of your transformer may need inverting - try reversing the connections on the secondary - a flyback must have the correct phase relationship between primary and secondary for it to work.
I would also say that your FET appears to be upside down - look at the parasitic diode - it will always be conducting from the battery through the primary.
You feedback signal is the 5V_SMPS, but I don't see anywhere in your schematic where SMPS_GND is connected to POWER_GND.
The transformer could be a contributor to this error since it is not single sided (3.5V instead of 5V and 20V instead of 15V).
Related Topic
- Electronic – Transformer maximum voltage rating specifications
- Electronic – High Step-up Ratio DC-DC Convert (12V-to-150V) – Boost, Flyback, Coupled-inductor Boost
- Electrical – How to calculate secondary RMS current of each winding in multiplre output flyback converter
- Electrical – Measure leakage inductance of flyback transformer with multiple secondary windings
- Electronic – How to calculate air gap in flyback transformer
- Electronic – Why is there a huge difference between Is2(peak) and Is2(rms) in flyback converter
Best Answer
All windings will float - that's the beauty of a flyback design so, if in fact you mean you want to leave the 18 volt winding unconnected to anything then...
There shouldn't be any problem in a standard flyback circuit providing that the 24 volt output is properly connected and, the feedback stabilization is from the 24 volt DC output.