一种低电压恒定跨导轨到轨运算放大器的设计  

Design of Low Voltage and Rail to Rail Operational Amplifier with Constant Transconductance

作　　者：曹正州 孙佩 CAO Zhengzhou;SUN Pei(China Key System&Integrated Circuit Co.,Ltd.,Wuxi 214072,China)

机构地区：[1]中科芯集成电路有限公司

出　　处：《电子与封装》2019年第11期22-25,共4页Electronics & Packaging

摘　　要：设计了一种低电压恒定跨导的轨到轨运算放大器,作为误差放大器用在BUCK型DC-DC上实现对输出电压的调节。该运算放大器采用两级结构,输入级采用互补差分对的结构,实现了轨到轨电压的输入,并且利用2倍电流镜技术实现了跨导的恒定;输出级采用AB类放大器的结构,提高了输出电压摆幅和效率,实现了轨到轨电压的输出。该电路基于CSMC 0.25μm EN BCDMOS工艺进行设计,仿真结果表明:电源电压为2.8 V时,在输出端负载电容为160 pF、负载电阻为10 kΩ的情况下,增益为124 dB,单位增益带宽积为5.76 MHz,相位裕度为59.9℃,输入跨导为5.2 mΩ-1,共模抑制比为123 dB,输入共模信号范围为0~2.8V,输出电压摆幅为0~2.8 V。A low voltage and rail to rail operational amplifier with constant transconductance, as an error amplifier used for BUCK type DC-DC to adjust the output voltage is designed. This operational amplifier is compiled with two stages. The input stage is adopted by complementary differential pairs to realize the input voltage rail to rail, and a double current mirror is used to realize the constant transconductance. In the output stage, the class AB amplifier is adopted to improve output voltage swing and efficient, and rail to rail output voltage is realized. Using CSMC 0.25 μm EN BCDMOS process to design this circuit, the experimental results show that, the gain is 124 dB, unit gain bandwidth is 5.76 MHz, the phase margin is 59.9 ℃, the input transconductance is 5.2 mΩ-1, the CMRR is 123 dB, the input common signal range is 0-2.8 V, and the output voltage swing is 0-2.8 V, when the supply voltage is 2.8 V and output load capacitance is 160 pF, the load resistance is 10 kΩ.

关 键 词：低电压 轨到轨 恒定跨导 

分 类 号：TN402[电子电信—微电子学与固体电子学]