DESIGN AND FPGA IMPLEMENTATION OF AREA OPTIMIZED 16-BIT DELTA-SIGMA DIGITAL TO ANALOG CONVERTER FOR PORTABLE AUDIO APPLICATIONS

Abstract

The evolution of Digital Signal Processing (DSP) has revolutionized- the field of communications and signal processing which allows high speed processing of input data. However, it is required to convert these processed digital data into analog domain for real world applications. Digital to Analog Converters (DACs), which are a mixture of analog and digital circuits are employed to perform this task of digital to analog conversion. In-order to fully utilize the advantages provided by DSP, it is very much required to implement these DACs completely using digital circuits, which is possible only by using Delta-Sigma Converters. This thesis presents the design of an area optimized, oversampled, 16-bit Delta-Sigma Digital to Analog Converter (DAC) for portable audio applications. A new style of architecture without multipliers is presented to save hardware and improve system throughput. CIC interpolator and Error Feedback modulator structures have been employed to optimize and achieve low area, thus leading to low power consumption. Most of the implementation is done using digital blocks which greatly reduce the effect of process variations in ultra deep sub-micron technology. With recent improvements in the density of Field Programmable Gate Array (FPGA) devices, it is becoming possible to integrate systems with an increasingly higher level of functionality. The entire Delta-Sigma DAC is initially modeled and simulated in MATLAB. The Designed DAC is implemented on Spartan 3E (xc3s500e-4fg320) FPGA kit employing the latest Xilinx System Generator model based design methodology. The results obtained were satisfactory and showed reduction in area in terms of the number of slices used on FPGA. iii