A study of the interference potential of spread spectrum clock generation techniques

Hardin, K.B.; Fessler, J.T.; Bush, Donald R.

doi:10.1109/isemc.1995.523633

Cited by 22 publications

(12 citation statements)

References 1 publication

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“…The following researches focused on exploring PWM-based random switching modulation techniques and chaotic switching modulation techniques [19]; these techniques have demonstrated satisfactory performance in reducing EMI amplitude and got considerable progress in this regard. However, the harmonic energy spread during modulation became too wide, thus deteriorating the low-frequency characteristics; moreover, it still suffers from uncontrollable energy spread and is inapplicable on QRF converters.…”

Section: Experimental Studymentioning

confidence: 99%

Novel Frequency Swapping Technique for Conducted Electromagnetic Interference Suppression in Power Converter Applications

Kuo

Tsou²

2016

Energies

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Quasi-resonant flyback (QRF) converters have been widely applied as the main circuit topology in power converters because of their low cost and high efficiency. Conventional QRF converters tend to generate higher average conducted electromagnetic interference (EMI) in the low-frequency domain due to the switching noise generated by power switches, resulting in the fact they can exceed the EMI standards of the European Standard 55022 Class-B emission requirements. The presented paper develops a novel frequency swapping control method that spreads spectral energy to reduce the amplitude of sub-harmonics, thereby lowering average conducted EMI in the low-frequency domain. The proposed method is implemented in a control chip, which requires no extra circuit components and adds zero cost. The proposed control method is verified using a 24 W QRF converter. Experimental results reveals that conducted EMI has been reduced by approximately 13.24 dBµV at 498 kHz compared with a control method without the novel frequency swapping technique. Thus, the proposed method can effectively improve the flyback system to easily meet the CISPR 22/EN55022 standards.

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Section: Experimental Studymentioning

confidence: 99%

Novel Frequency Swapping Technique for Conducted Electromagnetic Interference Suppression in Power Converter Applications

Kuo

Tsou²

2016

Energies

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“…where A dB is the EMI attenuation, SR is the frequency spreading ratio, FC is the center frequency, and I; J; K are modulation parameters [3]. Based on 1, under the same center frequency, EMI can be reduced further by increasing spreading ratio.…”

Section: B Spread Spectrum Algorithmmentioning

confidence: 99%

A Low-Power and Portable Spread Spectrum Clock Generator for SoC Applications

Sheng

Chung

Lee

2011

IEEE Trans. VLSI Syst.

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In this paper, a novel portable and all-digital spread spectrum clock generator (ADSSCG) suitable for system-on-chip (SoC) applications with low-power consumption is presented. The proposed ADSSCG can provide flexible spreading ratios by the proposed rescheduling division triangular modulation (RDTM). Thus it can provide different EMI attenuation performance for various system applications. Furthermore, the proposed ADSSCG employs a low-power digitally controlled oscillator (DCO) to save overall power consumption significantly. Measurement results show that power consumption of the proposed ADSSCG is 1.2 mW (@54 MHz), and it provides 9.5 dB EMI reductions with 1% spreading ratio. Besides, the proposed ADSSCG has very small chip area as compared with conventional SSCGs which often required large on-chip loop filter capacitors. In addition, the proposed ADSSCG is implemented only with standard cells, making it easily portable to different processes and very suitable for SoC applications.

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“…Two most important SSCG specification parameters are EMI reduction and clock period deviation at the central frequency f c . In 5, an equation is proposed to project the SSCG EMI attenuation: where δ is the spectrum‐spread ratio, f c is the central frequency in MHz. This equation has been adopted in SSCG designs 5, 6.…”

Section: Introductionmentioning

confidence: 99%

Analytic model for spread‐spectrum clock generator circuit characterization

Xia

2010

Circuit Theory & Apps

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SUMMARYThe spread-spectrum clock generator (SSCG) is one of the most efficient techniques to reduce the radiated emission of electronic devices. Despite its popularity, there exists no analysis that can be used as the design guidance to accurately project SSCG performance. In this paper, we develop a mathematical model to analyze SSCG EMI reduction and the clock period deviation performance. For model validation, Cadence Spectre simulations are conducted.

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A study of the interference potential of spread spectrum clock generation techniques

Cited by 22 publications

References 1 publication

Novel Frequency Swapping Technique for Conducted Electromagnetic Interference Suppression in Power Converter Applications

Novel Frequency Swapping Technique for Conducted Electromagnetic Interference Suppression in Power Converter Applications

A Low-Power and Portable Spread Spectrum Clock Generator for SoC Applications

Analytic model for spread‐spectrum clock generator circuit characterization

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