Lowest possible working voltage with Innoswitch-3
This is a more general question, regarding the Innoswitch-3 (EP) family:
What is the absolute lowest possible working voltage on the primary side?
I know the datasheet says 30V on the primary drain to charge BPP. The PI designer says 36V. But what if I supply the BPP externally with the appropriate current?
Of course, a suitable transformer must be used and the V-pin must be driven well. However, the secondary side should not be critical.
A starting voltage of 10V should be achieved. Is this possible?
Comments
This is very helpful!
I want to achieve 36W (24V@1.5A) and be aware of this challenge. I will build a prototype within the next weeks and share my results.
36W is very ambitious - the device may hit current limit and go into autorestart at the low input voltage you contemplate using. Be careful and monitor the drain current closely. You may be forced to use the largest InnoSwitch in the family in order to satisfy the peak current requirement.
Hi
We do have a proven design idea wherein we will tap from the rectified AC input and have a current source circuit to supply the bypass capacitor to achieve a low input voltage that can allow the controller to switch without issue.
Aside from transformer constraints, the main factor for implementing this idea is your required output power. We do have a design idea that can use 18VAC as input to power up a 3W design for TinySwitch and not for InnoSwitch.
Kindly let me know first your output requirements and other factors that need to be considered to see whether we can verify it on the bench.
You can also check out the report for the design idea I mentioned using this link: DI-152 rev A.indd (power.com)
Thank you and I will be waiting for your response.
Regards