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INN3977CQ Minimum Input voltage

Posted by: jannik on 10/13/2022

what is the minimum turn on voltage of the INN3977CQ? We have a product that requires a galvanically isolated converter from 16-30VDC to 15V/0.5A with 5000Vrms.
Is an external supply (as in DI-152) required for the BPS pin?


Submitted by PI-Coffee on 10/18/2022

Hi Jannik,

InnoSwitch can turn on at 16V input however, it might have difficulty in providing your rated power at 16V minimum input voltage.

The IC will already operate near the maximum frequency and minimum off time at 16V input 7.5W output. Please see the last page of the PI Expert attached file for set point analysis.

The BPS is supplied via the FWD and VOUT pins passing thru an internal regulator, you would only need an external capacitor across BPS pin. Please see image below from secondary controller block diagram.

 Image removed.



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Jannik_INN3977Q_VIN16-30_15V_7W5.pdf 593.65 KB