RICO: A low power repetitive iteration CORDIC for DSP applications in portable devices

COordinate Rotation DIgital Computer (CORDIC) is a unit that is widely used in the applications such as scientific calculators, signal/image processing, communication systems, robotics, 3-D graphics etc. exhibits huge computations and requires large power. This paper presents an approximate low power Repetitive Iteration CORDIC (RICO) architecture that calculates sine/cosine values very efficiently. In the proposed RICO, number of iterations are fixed and a specific iteration is repeated to reduce the implementation complexity. An additional comparator based logic that evaluates direction of micro-rotation within RICO reduces the data dependency between each iterations. The efficiency of the proposed RICO is evaluated in Discrete Cosine Transform (DCT) by implementing DCT using only three RICO units. Post-synthesis simulation results show that the proposed RICO achieves area and power savings of 37.19% and 94.05% respectively over the Conventional CORDIC at the cost of 29.39% increase in latency.