Design of a High-Power, High-Efficiency, Low-Distortion Direct from Digital Amplifier

For the process of converting low-power digital signals into their high-power analog counterparts, the functions of digital-to-analog conversion (at low power) and analog power amplification are separately implemented. This thesis proposes a new “STAC-DAC” circuit topology which directly realizes high-power analog output from low-power digital input signals. The ability to achieve a “direct from digital” high-power analog output in a single high-efficient, low-distortion design has significant potential in audio reproduction, and flexible signal generation applications. In this thesis, the “STAC-DAC” is described and its implementation via MATLAB and LTSpice is discussed. The results of simulations are used to prove the concept of the design. The 16-bit design features a high-power output of 100 watts or more at an efficiency of 93%. The design is optimized to feature low total harmonic distortion (THD) of 0.055% for a 1 kHz signal at 100 watts into an 8 Ω load and low phase distortion of less than 10° for a 20 kHz signal and only 1° at 1 kHz. The “STAC-DAC” design is applicable to any design which requires a high-power analog output that is controlled by a logic level digital input. The results validated that the “STAC-DAC” can produce low-level THD figures over the audio frequency range. If very low THD figures are not necessary, high-power analog operation can be achieved into the hundreds of kilohertz while maintaining high efficiency. These results show that the power “STAC-DAC” is capable of simultaneously achieving the highly efficient circuitry associated with digital-to-analog converters with the low harmonic and phase distortion requirements associated with high fidelity analog audio amplifiers