Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/62160
Full metadata record
DC FieldValueLanguage
dc.contributor.authorJin, Chongfeien
dc.date.accessioned2015-02-10T09:26:14Zen
dc.date.available2015-02-10T09:26:14Zen
dc.date.copyright2015en
dc.date.issued2015en
dc.identifier.citationJin, C. (2015). Class D amplifier with pseudo-randomized carrier frequency modulation (PRCFM) for EMI mitigation. Doctoral thesis, Nanyang Technological University, Singapore.en
dc.identifier.urihttps://hdl.handle.net/10356/62160en
dc.description.abstractClass D amplifiers are found in nearly all portable electronic products for their small size and power efficiency. Due to their high frequency switching operation, they generate significant amount of electromagnetic interference (EMI) and usually off-chip filters are necessary in order for them to comply with the international regulatory EMI limits. With the continuous trend of product miniaturization, filter-less Class D amplifiers are gaining attention recently. Without the off-chip filter, designing a fully integrated filter-less Class D amplifier to meet the EMI requirements can be challenging. This thesis develops and implements a pseudo-randomized carrier frequency modulation (PRCFM) technique in both analog and digital filterless Class D audio power amplifiers for EMI mitigation purposes so that these amplifiers fulfill the electromagnetic compatibility (EMC) requirement without the needs of off-chip filters. The PRCFM circuit is implemented with a frequency divider and a linear feedback shift register (LFSR). The proposed amplifier also features a peak detector to improve the power conversion efficiency when it operates under low audio input condition. An analog filter-less Class D amplifier is designed and fabricated using 0.18 µm CMOS process technology with a size of 1 mm2 and the proposed PRCFM circuit occupies only less than 1% of the total chip area. The effectiveness of the PRCFM scheme for EMI mitigation is demonstrated experimentally. The PRCFM circuit consumes very little additional power and therefore has little impact on the power efficiency of the amplifier. In addition, the amplifier still maintains excellent total harmonic distortion (THD) over the audio band of interest (100 Hz - 6 kHz) and the typical modulation index range. With the encouraging results, the PRCFM technique is further extended to a digital Class D amplifier and similar EMI mitigation performance has also been demonstrated. The digital Class D amplifier consists of a digital pulse width modulation (DPWM) circuit, a power stage, a PRCFM circuit and a low pass filter (LPF). Moreover, an efficient algorithmic sampling process and a hybrid pulse generation method are proposed to improve THD performance. The circuit is first simulated in Matlab Simulink and then implemented with field-programmable gate array (FPGA). Both simulated and measured results have shown that the PRCFM spreads the switching frequency of the Class D amplifier from 145 kHz to 295 kHz in 31 frequency steps using a pseudo-random (PR) pattern, which results in EMI reduction of 7.4 dB, with acceptable THD.en
dc.format.extent137 p.en
dc.language.isoenen
dc.subjectDRNTU::Engineering::Electrical and electronic engineering::Electronic circuitsen
dc.titleClass D amplifier with pseudo-randomized carrier frequency modulation (PRCFM) for EMI mitigationen
dc.typeThesisen
dc.contributor.supervisorSee Kye Yaken
dc.contributor.schoolSchool of Electrical and Electronic Engineeringen
dc.description.degreeDOCTOR OF PHILOSOPHY (EEE)en
dc.identifier.doi10.32657/10356/62160en
item.fulltextWith Fulltext-
item.grantfulltextopen-
Appears in Collections:EEE Theses
Files in This Item:
File Description SizeFormat 
Thesis_JCF_11.pdfthesis2.87 MBAdobe PDFThumbnail
View/Open

Page view(s) 50

442
Updated on Mar 26, 2024

Download(s) 5

657
Updated on Mar 26, 2024

Google ScholarTM

Check

Altmetric


Plumx

Items in DR-NTU are protected by copyright, with all rights reserved, unless otherwise indicated.