Speaking in Hamburg, Cameron added that it is in the EU's interests for the UK to stay in a reformed EU, stating the changes he is seeking will make Europe "more outward looking, competitive and dynamic".
He said he wanted to address Britain's concerns but also make reforms work for Europe as a whole.
However, critics have said that Cameron's reform demands are thin, and will not change the UK's relationship with the EU.
But Cameron sought to address some of those concerns, stating: "We have the character of an island nation - independent, forthright, passionate in defence of our sovereignty - and of institutions that have served us well for many hundreds of years."
"And the need to protect our sovereignty has always been paramount for us, but we are also an open nation."
He added: "I never want us to pull up the drawbridge, and retreat from the world."
Cameron is engaged in last minute dialogue with his European counterparts ahead of the summit next week, where he aims to make a deal. If a deal is made the referendum could be held as early as June.
However, it won't be easy. Donald Tusk, the European Council president has warned that the political process remains "very fragile", with some leaders still uncertain about some aspects of the draft proposals.