The fully-funded £135m project will involve construction of two new buildings each extending to around 120,000 sq ft at a brownfield site at Maindy Park.
This latest third phase, which includes the Innovation Central building, will also involve building a bridge linking Cardiff Business School with the Innovation Campus.
Cardiff University now hopes to start work on site early in 2017 with completion scheduled for summer 2018, before being ready for occupancy in 2019.