Understanding the Currency Board vs Central Bank

Like a central bank, a currency board is a country's monetary authority that issues notes and coins. Unlike a central bank, however, a currency board is not the lender of last resort, nor is it what some call 'the government's bank.' A currency board can function alone or work in parallel with a central bank, although the latter arrangement is uncommon. This little-known type of monetary system has been around just as long as the more widely used central bank and has been used by many economies, big and small.

Reference: https://www.investopedia.com/articles/03/051503.asp