I searched and couldn't find anything relating to this...

I looked at my tax return last year and say for instance my total tax due is $1600 and I have a hybrid tax credit of $2100. Do I get a refund of $500 or do I just not pay taxes for that year? From the looks of it I would just get $1600 for the hybrid tax credit and not get any refund for the other $500. Is that correct?