Utilize the shift‐and‐add architecture to approximate multiple nonlinear functions
Botao Xiong, Yuanfeng Sui, Zhi Ning Jia, Sicun Li, Yuchun Chang · International Journal of Circuit Theory and Applications · 2021
Summary The piecewise linear approximation method is used to estimate the non‐linear functions, which is implemented by the shift‐and‐add architecture consisting of three blocks: “adder tree,” “multiplexer,” and “segment index encoder.” Compared with state of the art, the design flow in this letter enables the “adder tree” and “multiplexer” blocks can be shared by multiple nonlinear functions. In other words, the shift‐and‐add architecture can approximate multiple nonlinear functions with a slight overhead. The fused Log and Antilog converter demonstrates the feasibility of the proposed method. The Antilog function is implemented by the Log converter at the cost of 14% cell area and 6% delay.