Approximate arithmetic modules are attractive solutions to save power consumption in error-resilient applications. The full adder (FA), as the core computing module, contributes a major part of arithmetic modules in digital systems. However, designing the FA module to be applied in both approximate and exact modes has become a major goal in low-power integrated circuit design. In this paper, we present a new configurable FA with runtime configurability between exact and approximate modes at the transistor level. The configurability of the proposed FA is achieved using embedded switches in the internal nodes of the circuit. Our circuit provides an output accuracy of 6 in approximate mode. We implemented our adder using GPDK 45-nm technology node and evaluated it with Cadence Virtuoso. Our proposed adder consumes 23% less power compared to the Mirror Adder when operating in approximate mode.
