Matching Items (3)
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- All Subjects: Audio amplifiers--Design and construction.
- All Subjects: efficiency
- Member of: Theses and Dissertations
- Member of: ASU Electronic Theses and Dissertations
- Status: Published
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, 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
Description
Class D Amplifiers are widely used in portable systems such as mobile phones to achieve high efficiency. The demands of portable electronics for low power consumption to extend battery life and reduce heat dissipation mandate efficient, high-performance audio amplifiers. The high efficiency of Class D amplifiers (CDAs) makes them particularly attractive for portable applications. The Digital class D amplifier is an interesting solution to increase the efficiency of embedded systems. However, this solution is not good enough in terms of PWM stage linearity and power supply rejection. An efficient control is needed to correct the error sources in order to get a high fidelity sound quality in the whole audio range of frequencies. A fundamental analysis on various error sources due to non idealities in the power stage have been discussed here with key focus on Power supply perturbations driving the Power stage of a Class D Audio Amplifier. Two types of closed loop Digital Class D architecture for PSRR improvement have been proposed and modeled. Double sided uniform sampling modulation has been used. One of the architecture uses feedback around the power stage and the second architecture uses feedback into digital domain. Simulation & experimental results confirm that the closed loop PSRR & PS-IMD improve by around 30-40 dB and 25 dB respectively.
ContributorsChakraborty, Bijeta (Author) / Bakkaloglu, Bertan (Thesis advisor) / Garrity, Douglas (Committee member) / Ozev, Sule (Committee member) / Arizona State University (Publisher)
Created2012
Description
The Performance Based Studies Research Group (PBSRG) uses a leading model that helps people and procurement projects alike minimize risk while maximizing productivity. While there are a multitude of factors that propel this model, Information Measurement Theory (IMT) is the main element of the Best Value approach the group takes. I wanted to take the dominant information elements of IMT that helped me find my true self and increase my level of efficiency, and use them to find what it takes to become a successful veterinarian. In order to do this, the Kashiwagi Solution Model (KSM) within IMT was the perfect way to distinguish more successful, higher performing veterinarians from the less successful, lower performing veterinarians. In order to do this, a number of KSM-designed questions were created to score each veterinarian's level of perception. These, along with other background and performance questions, were put into a short survey and sent out. Once this was done, other elements of the veterinarians' lives could be compared side by side to their perception level. The results, of which 970 surveys were returned, found that the more expert a veterinarian is, the lower number of animals they will see per day and the better they know their customer satisfaction rating. These are both then theorized to work in conjunction to form the final correlation that the more perceptive the veterinarian, the higher their performance, aka their clinic's rating. In addition to this, no correlation was found between a veterinarian's level of thinking and their GPA from graduate school. It was concluded that though these correlations are found, I would recommend another project to be done in which all veterinarians of each surveyed clinic could be analyzed in order to gain more insight into any trends that exist between a veterinarian's level of thinking and their performance.
ContributorsBoon, Kurtis Ventry (Author) / Kashiwagi, Jacob (Thesis director) / Finney, Gina Lee (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12