scholarly journals Comparative Assessment of Gate Drive Control Schemes in High Frequency Converter

2011 ◽  
Vol 1 (4) ◽  
pp. 76-83 ◽  
Author(s):  
N. Z. Yahaya ◽  
K. M. Begam ◽  
M. Awan
Keyword(s):  
High Frequency ◽  
Frequency Converter ◽  
Buck Converter ◽  
Duty Ratio ◽  
Gate Delay ◽  
Switching Loss ◽  
Conduction Loss ◽  
Drive Control ◽  
Control Schemes ◽  
High Level

Several gate drive control schemes are simulated and the results show that the Fixed Duty ratio (FDR) can help drive synchronous rectifier buck converter (SRBC) correctly with low dead time and hence reduce body diode conduction loss. Even though FDR is prone to cross-conduction effects, the design is simple. Apart from that, Adaptive Gate Delay (AGD) and Predictive Gate Delay (PGD) control schemes have also shown high level of efficiency. However, AGD generates more losses. Even though the total switching loss in PGD has not improved much of only 1 %, more than 82 % efficiency has been achieved in spite of the advantage in FDR and AGD schemes.

Design and Implementation of a Dimmable LED Driver with Low-Frequency PWM Control

2013 ◽  
Vol 284-287 ◽  
pp. 2538-2542
Author(s):  
Hung Liang Cheng ◽  
Chun An Cheng ◽  
Chao Shun Chen ◽  
Kuan Lung Huang
Keyword(s):  
High Frequency ◽  
High Efficiency ◽  
Low Frequency ◽  
Buck Converter ◽  
Duty Ratio ◽  
Buck Converters ◽  
Resonant Converter ◽  
Switching Loss ◽  
Led Driver ◽  
Frequency Pulse

This paper proposes a high-efficiency dimmable LED driver for light emitting diodes (LED). The developed LED driver consists of a full-bridge resonant converter and six buck converters. The function of the full-bridge resonant converter is to obtain a smooth dc-link voltage for the buck converters by phase-shift modulation (PSM) while that of the six buck converters is to drive six LED modules, respectively. The gate voltage of the active switch of each buck converter is a combination of high-frequency and low-frequency pulses. The duty ratio of the high-frequency pulse controls the LED voltage and thereby, controls the amplitude of LED current. LEDs are dimmed by low-frequency pulse-width modulation (PWM) to vary the average current flowing through LED. Circuit equations are derived and circuit parameters are designed. High circuit efficiency is ensured by operating the active switches at zero-voltage switching-on to reduce the switching loss. Finally, a prototype circuit was built to verify the accuracy and feasibility of the proposed LED driver.

scholarly journals Performance Analysis of Trench Power MOSFETs in High-Frequency Synchronous Buck Converter Applications

2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Yali Xiong ◽  
Xu Cheng ◽  
Xiangcheng Wang ◽  
Pavan Kumar ◽  
Lina Guo ◽  
...  
Keyword(s):  
Figure Of Merit ◽  
Buck Converter ◽  
Switching Frequency ◽  
Circuit Modeling ◽  
Buck Converters ◽  
Switching Loss ◽  
Frequency Range ◽  
Power Mosfets ◽  
Conduction Loss ◽  
Obvious Benefit

This paper investigates the performance perspectives and theoretical limitations of trench power MOSFETs in synchronous rectifier buck converters operating in the MHz frequency range. Several trench MOSFET technologies are studied using a mixed-mode device/circuit modeling approach. Individual power loss contributions from the control and synchronous MOSFETs, and their dependence on switching frequency between 500 kHz and 5 MHz are discussed in detail. It is observed that the conduction loss contribution decreases from 40% to 4% while the switching loss contribution increases from 60% to 96% as the switching frequency increases from 500 KHz to 5 MHz. Beyond 1 MHz frequency there is no obvious benefit to increase the die size of either SyncFET or CtrlFET. The RDS(ON)×QG figure of merit (FOM) still correlates well to the overall converter efficiency in the MHz frequency range. The efficiency of the hard switching buck topology is limited to 80% at 2 MHz and 65% at 5 MHz even with the most advanced trench MOSFET technologies.

scholarly journals Cochlear compound action potentials from high-level tone bursts originate from wide cochlear regions that are offset toward the most sensitive cochlear region

2019 ◽  
Vol 121 (3) ◽  
pp. 1018-1033 ◽  
Author(s):  
C. Lee ◽  
J. J. Guinan ◽  
M. A. Rutherford ◽  
W. A. Kaf ◽  
K. M. Kennedy ◽  
...  
Keyword(s):  
High Frequency ◽  
Action Potentials ◽  
Tuning Curve ◽  
Low Frequency ◽  
Sound Level ◽  
Frequency Tone ◽  
Compound Action Potentials ◽  
High Level ◽  
Level Tone ◽  
Compound Action

Little is known about the spatial origins of auditory nerve (AN) compound action potentials (CAPs) evoked by moderate to intense sounds. We studied the spatial origins of AN CAPs evoked by 2- to 16-kHz tone bursts at several sound levels by slowly injecting kainic acid solution into the cochlear apex of anesthetized guinea pigs. As the solution flowed from apex to base, it sequentially reduced CAP responses from low- to high-frequency cochlear regions. The times at which CAPs were reduced, combined with the cochlear location traversed by the solution at that time, showed the cochlear origin of the removed CAP component. For low-level tone bursts, the CAP origin along the cochlea was centered at the characteristic frequency (CF). As sound level increased, the CAP center shifted basally for low-frequency tone bursts but apically for high-frequency tone bursts. The apical shift was surprising because it is opposite the shift expected from AN tuning curve and basilar membrane motion asymmetries. For almost all high-level tone bursts, CAP spatial origins extended over 2 octaves along the cochlea. Surprisingly, CAPs evoked by high-level low-frequency (including 2 kHz) tone bursts showed little CAP contribution from CF regions ≤ 2 kHz. Our results can be mostly explained by spectral splatter from the tone-burst rise times, excitation in AN tuning-curve “tails,” and asynchronous AN responses to high-level energy ≤ 2 kHz. This is the first time CAP origins have been identified by a spatially specific technique. Our results show the need for revising the interpretation of the cochlear origins of high-level CAPs-ABR wave 1. NEW & NOTEWORTHY Cochlear compound action potentials (CAPs) and auditory brain stem responses (ABRs) are routinely used in laboratories and clinics. They are typically interpreted as arising from the cochlear region tuned to the stimulus frequency. However, as sound level is increased, the cochlear origins of CAPs from tone bursts of all frequencies become very wide and their centers shift toward the most sensitive cochlear region. The standard interpretation of CAPs and ABRs from moderate to intense stimuli needs revision.

High Frequency Conducted EMI Investigation on Packaging and Modulation for a SiC-Based High Frequency Converter

2019 ◽  
Vol 7 (3) ◽  
pp. 1789-1804 ◽  
Author(s):  
Yue Xie ◽  
Cai Chen ◽  
Zhizhao Huang ◽  
Teng Liu ◽  
Yong Kang ◽  
...  
Keyword(s):  
High Frequency ◽  
Frequency Converter ◽  
Conducted Emi
Sign in / Sign up

Export Citation Format

Share Document