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Design and analysis of a dual supply class H audio amplifier

Description
Efficiency of components is an ever increasing area of importance to portable applications, where a finite battery means finite operating time. Higher efficiency devices need to be designed that don't compromise on the performance that the consumer has come to expect. Class D amplifiers deliver on the goal of increased…

Efficiency of components is an ever increasing area of importance to portable applications, where a finite battery means finite operating time. Higher efficiency devices need to be designed that don't compromise on the performance that the consumer has come to expect. Class D amplifiers deliver on the goal of increased efficiency, but at the cost of distortion. Class AB amplifiers have low efficiency, but high linearity. By modulating the supply voltage of a Class AB amplifier to make a Class H amplifier, the efficiency can increase while still maintaining the Class AB level of linearity. A 92dB Power Supply Rejection Ratio (PSRR) Class AB amplifier and a Class H amplifier were designed in a 0.24um process for portable audio applications. Using a multiphase buck converter increased the efficiency of the Class H amplifier while still maintaining a fast response time to respond to audio frequencies. The Class H amplifier had an efficiency above the Class AB amplifier by 5-7% from 5-30mW of output power without affecting the total harmonic distortion (THD) at the design specifications. The Class H amplifier design met all design specifications and showed performance comparable to the designed Class AB amplifier across 1kHz-20kHz and 0.01mW-30mW. The Class H design was able to output 30mW into 16Ohms without any increase in THD. This design shows that Class H amplifiers merit more research into their potential for increasing efficiency of audio amplifiers and that even simple designs can give significant increases in efficiency without compromising linearity.
ContributorsPeterson, Cory (Author) / Bakkaloglu, Bertan (Thesis advisor) / Barnaby, Hugh (Committee member) / Kiaei, Sayfe (Committee member) / Arizona State University (Publisher)
Created2013
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Process Improvement and Sustainability: Restructuring the Leadership Scholarship Program Cohort Selection

Description
Although the Leadership Scholarship Program has seen successful recruiting processes throughout changes in leadership of the program; the organization expressed a need for major overhaul to reevaluate the decisions of the process and to establish backing for those decisions. By asking current and alumni members of the program about what…

Although the Leadership Scholarship Program has seen successful recruiting processes throughout changes in leadership of the program; the organization expressed a need for major overhaul to reevaluate the decisions of the process and to establish backing for those decisions. By asking current and alumni members of the program about what they would like to see in a future member of the program as well as which parts of the process they found most important, the qualities of a future member of the program could be established and weighted. The goals of the reevaluation were to help eliminate bias, discrepancies between applications with extremely different uncontrollable factors, define points of discrepancies, and establish organizational sustainability while achieving a 100% acceptance rate from offered students. Each of these goals was achieved through methods outlined in the LSP Selection Process Manual that was written as a result of this reevaluation. The manual also outlines ways to improve the process going forward.
ContributorsCassidy, Delilah R. (Author) / Kappes, Janelle (Thesis director) / Klinkner, Lara (Committee member) / Walter Cronkite School of Journalism and Mass Communication (Contributor) / Department of Marketing (Contributor) / Sandra Day O'Connor College of Law (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05