The quantization noise leakage of the first stage in a MASH21 sigma-delta modulator is analyzed. The results show that the finite DC gain of the opamp is the main reason for noise leakage, and finite GBW and SR only g...The quantization noise leakage of the first stage in a MASH21 sigma-delta modulator is analyzed. The results show that the finite DC gain of the opamp is the main reason for noise leakage, and finite GBW and SR only generate harmonic distortion. The relationship between DC gain and leakage is modeled and conclusions on design criteria are reached. As an example, a MASH21 modulator for a digital audio application is realized. This modulator, fabricated in an 0.18 μm mixed signal process, achieves an SNDR of 91 dB with 1.8 V supply, which verifies the analysis and design criteria.展开更多
设计了5 V/1 A 4‰精度低压差直流线性稳压源,能够实现5.5~25 V宽电压输入。采用德州仪器（TI）TL431B精度4‰并联电压基准,作为电压闭环反馈控制主IC,从而确保整个电路的输出电压5‰精度。其中意法半导体的Cortex-M3内核STM32 AM7采用...设计了5 V/1 A 4‰精度低压差直流线性稳压源,能够实现5.5~25 V宽电压输入。采用德州仪器（TI）TL431B精度4‰并联电压基准,作为电压闭环反馈控制主IC,从而确保整个电路的输出电压5‰精度。其中意法半导体的Cortex-M3内核STM32 AM7采用外部高精度基准源,通过内置12 bit AD实时的对工作电流、工作电压、漏电流、输出功率、漏电流功耗采样,处理完有效数据在显示器件上显示,同时控制相关部件对电源进行软、硬件的短路和漏电保护。经过对实际电路的测试,能够实现最低输入电压5.3 V,最高输入电压45 V 0.2%的输出精度,漏电流采样精度的绝对值≤5%。展开更多
基金supported by the Shenzhen Science and Technology Plan,China(No.QK200610).
文摘The quantization noise leakage of the first stage in a MASH21 sigma-delta modulator is analyzed. The results show that the finite DC gain of the opamp is the main reason for noise leakage, and finite GBW and SR only generate harmonic distortion. The relationship between DC gain and leakage is modeled and conclusions on design criteria are reached. As an example, a MASH21 modulator for a digital audio application is realized. This modulator, fabricated in an 0.18 μm mixed signal process, achieves an SNDR of 91 dB with 1.8 V supply, which verifies the analysis and design criteria.
文摘设计了5 V/1 A 4‰精度低压差直流线性稳压源,能够实现5.5~25 V宽电压输入。采用德州仪器（TI）TL431B精度4‰并联电压基准,作为电压闭环反馈控制主IC,从而确保整个电路的输出电压5‰精度。其中意法半导体的Cortex-M3内核STM32 AM7采用外部高精度基准源,通过内置12 bit AD实时的对工作电流、工作电压、漏电流、输出功率、漏电流功耗采样,处理完有效数据在显示器件上显示,同时控制相关部件对电源进行软、硬件的短路和漏电保护。经过对实际电路的测试,能够实现最低输入电压5.3 V,最高输入电压45 V 0.2%的输出精度,漏电流采样精度的绝对值≤5%。
