A buck DC-DC switching regulator with high efficiency is implemented by automatically altering the modulation mode according to load current,and it can operate with an input range of 4.5 to 30 V.At light load current,...A buck DC-DC switching regulator with high efficiency is implemented by automatically altering the modulation mode according to load current,and it can operate with an input range of 4.5 to 30 V.At light load current,the converter operates in skip mode.The converter enters PWM mode operation with increasing load current.It reduces the switching loss at light load and standby state,which results in prolonging battery lifetime and stand-by time.Meanwhile, externally adjustable soft-start minimizes the inrush supply current and avoids the overshoot of output voltage at initial startup.The regulator is fabricated by a 0.6μm CDMOS process.The test results show that,under the condition of 3.3 V output,the efficiency is up to 64%at 5 mA and the maximum efficiency is 95.5%.展开更多
为了进一步降低高性能视频编码(HEVC)的输出码率,针对基于上下文的自适应算术编码(CABAC),提出了一种改进算法。利用大尺寸变换单元(TU)和变换跳过模式系数块大值系数较多的特点,首先在32×32变换单元中,根据已编码4×4系数组(...为了进一步降低高性能视频编码(HEVC)的输出码率,针对基于上下文的自适应算术编码(CABAC),提出了一种改进算法。利用大尺寸变换单元(TU)和变换跳过模式系数块大值系数较多的特点,首先在32×32变换单元中,根据已编码4×4系数组(CG)系数值的分布特性,自适应决定下一个CG的哥伦布-莱斯(Golomb-Rice)初始参数值;其次,在变换跳过模式系数块中设置初始Golomb-Rice参数为1,再利用相邻系数的相关性,根据已编码系数绝对值大小自适应决定下一系数的编码参数值。实验结果表明,与HEVC标准算法HM16.0相比,所提算法能达到0.09%~2.75%的比特率下降,平均有效率90%以上,且峰值信噪比(PSNR)无损失,编码时间平均只增加了0.08%。与代表文献相比,所提算法平均节省0.49%比特率,PSNR平均提高0.01 d B。展开更多
A unique high efficiency photovoltaic(PV)system is presented. It uses partial sine wave tracking for a pulse-width modulation(PWM) boost converter as well as a full-bridge inverter. The boost converter and full-bridge...A unique high efficiency photovoltaic(PV)system is presented. It uses partial sine wave tracking for a pulse-width modulation(PWM) boost converter as well as a full-bridge inverter. The boost converter and full-bridge inverter are connected via a compact intermediate film capacitor(i.e. non-smoothing DC link stage). PWM switching is activated by a dual mode control technique. In the proposed topology, simultaneous switching of both power conversion stages is avoided and therefore this increases the power conversion efficiency. The distinctive operating principles of these two power processing stages are discussed and analyzed with the experimental results for single-phase loading of the PV system.展开更多
高性能视频编码(HEVC)作为最新的视频编码标准,有赖于各种新技术的引入,其中Merge模式利用部分相邻块运动信息的相关性对其的压缩性能有显著贡献,然而HEVC在显著提升编码效率的同时复杂度也有所提高,限制了它在实际中的应用。由于需要...高性能视频编码(HEVC)作为最新的视频编码标准,有赖于各种新技术的引入,其中Merge模式利用部分相邻块运动信息的相关性对其的压缩性能有显著贡献,然而HEVC在显著提升编码效率的同时复杂度也有所提高,限制了它在实际中的应用。由于需要遍历多个Merge候选点使Merge模式带来一定的复杂度,为降低Merge模式的编码复杂度,本文分析了不同编码单元深度和量化系数值所对应的率失真代价值(RD cos t)变化特点,提出使用自适应阈值的方法减少Merge模式中的率失真优化计算次数,从而快速选择最优的Merge候选点。基于HM14.0的仿真结果显示,所提方法能平均减少15.38%的编码时间,而在相同客观质量下码率只增加了0.37%。展开更多
基金Project supported by the National Natural Science Foundation of China(No.60876023)
文摘A buck DC-DC switching regulator with high efficiency is implemented by automatically altering the modulation mode according to load current,and it can operate with an input range of 4.5 to 30 V.At light load current,the converter operates in skip mode.The converter enters PWM mode operation with increasing load current.It reduces the switching loss at light load and standby state,which results in prolonging battery lifetime and stand-by time.Meanwhile, externally adjustable soft-start minimizes the inrush supply current and avoids the overshoot of output voltage at initial startup.The regulator is fabricated by a 0.6μm CDMOS process.The test results show that,under the condition of 3.3 V output,the efficiency is up to 64%at 5 mA and the maximum efficiency is 95.5%.
文摘为了进一步降低高性能视频编码(HEVC)的输出码率,针对基于上下文的自适应算术编码(CABAC),提出了一种改进算法。利用大尺寸变换单元(TU)和变换跳过模式系数块大值系数较多的特点,首先在32×32变换单元中,根据已编码4×4系数组(CG)系数值的分布特性,自适应决定下一个CG的哥伦布-莱斯(Golomb-Rice)初始参数值;其次,在变换跳过模式系数块中设置初始Golomb-Rice参数为1,再利用相邻系数的相关性,根据已编码系数绝对值大小自适应决定下一系数的编码参数值。实验结果表明,与HEVC标准算法HM16.0相比,所提算法能达到0.09%~2.75%的比特率下降,平均有效率90%以上,且峰值信噪比(PSNR)无损失,编码时间平均只增加了0.08%。与代表文献相比,所提算法平均节省0.49%比特率,PSNR平均提高0.01 d B。
文摘A unique high efficiency photovoltaic(PV)system is presented. It uses partial sine wave tracking for a pulse-width modulation(PWM) boost converter as well as a full-bridge inverter. The boost converter and full-bridge inverter are connected via a compact intermediate film capacitor(i.e. non-smoothing DC link stage). PWM switching is activated by a dual mode control technique. In the proposed topology, simultaneous switching of both power conversion stages is avoided and therefore this increases the power conversion efficiency. The distinctive operating principles of these two power processing stages are discussed and analyzed with the experimental results for single-phase loading of the PV system.
文摘高性能视频编码(HEVC)作为最新的视频编码标准,有赖于各种新技术的引入,其中Merge模式利用部分相邻块运动信息的相关性对其的压缩性能有显著贡献,然而HEVC在显著提升编码效率的同时复杂度也有所提高,限制了它在实际中的应用。由于需要遍历多个Merge候选点使Merge模式带来一定的复杂度,为降低Merge模式的编码复杂度,本文分析了不同编码单元深度和量化系数值所对应的率失真代价值(RD cos t)变化特点,提出使用自适应阈值的方法减少Merge模式中的率失真优化计算次数,从而快速选择最优的Merge候选点。基于HM14.0的仿真结果显示,所提方法能平均减少15.38%的编码时间,而在相同客观质量下码率只增加了0.37%。
