UCC3818: How to add mitigation for mains zero crossing distortion?

Hi Andrew,

Thank you for the query on UCC3818.

The crossover distortion is caused by current amplifier offset.  The UCC3818 devices also require some added offset to prevent audible noise. 

Generally this is added from VREF and created added crossover distortion. The following app note suggests the method to add the resistor.

https://www.ti.com/lit/an/slua309c/slua309c.pdf?ts=1669431592850&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FUCC3818

Further tuning can be done by larger current sense signal and may require more boost inductance.

Regards,

Harish