What charges could I face if I have sex with someone and do not inform them of my positive COVID-19 status?

That depends on the person you had sex with. There's no evidence yet that I know of that covid 19 can be sexually transmitted. It's passed through droplets when an infected person coughs, or by touching contaminated surfaces. If you have it, then you should be staying away from other people as much as possible. If you have it and you cough on some one, you can infect them. 
https://www.theguardian.com/us-news/2020/apr/05/can-i-have-sex-a-guide-to-intimacy-during-the-coronavirus-outbreak

And this is why some people deserve the corona. 

If you tested positive and were supposed to be at home in quarantine then possibly assault. If the person died you could possibly face murder charges.

Impossible to answer without any details.  Did your victim catch the virus?  Did they survive the virus or die?  Were you aware of your infection at the time?  All these things matter.