One provisional may serve the basis to as many non-provisionals as you would like. As long as you file at least one non-provisional within 12 months of the provisional, you can continue to file additional non-provisional claiming priority back to the same provisional SO LONG AS you do not add ‘new subject matter’ that was not covered/anticipated by the provisional.
This means that you can split the provisional into two or more non-provisional utility patent filings claiming priority back to the same provisional, so long as you don’t add anything new to any application. If you have additional subject matter you would like to include, the additional subject matter should be filed in a separate filing known as a Continuation-in-Part (CIP). For CIPs, the new subject matter gets a patent priority date even with the CIP’s filing date, while the originally presented subject matter keeps its original patent priority date.
Exception: if you come up with NEW ideas that aren’t covered by the provisional, but it’s still too soon to file the non-provisional (your product isn’t at its final stage), it would be advisable to file a second provisional. Then, a non-provisional utility patent can claim patent priority back to multiple provisional applications. In this way, you get the earliest possible priority date for each of your inventions.
If you are interested in more detail related to your situation it is best to speak with an attorney.
Yuri Eliezer heads the intellectual property practice group at Founders Legal. As an entrepreneur who saw the importance of early-stage patent protection, Yuri founded SmartUp®. Clients he has served include Microsoft, Cisco, Cox, AT&T, General Electric, the Georgia Institute of Technology, and Coca-Cola.