DAB射频接收机中的高性能电荷泵设计

Design of high performance charge pump for DAB RF tuner

实现了一种用于DAB数字广播射频接收机的改进型电荷泵电路.电路核心部分采用带有运算放大器的改进型的共源共栅极电流镜结构实现,以改善电荷泵的电流匹配度.电荷泵中的带隙基准源采用自偏置宽摆幅电流镜结构以增加输出电压的范围.电荷泵中的运算放大器采用叠式共源共栅极结构以获得更大的输入共模范围与更高的增益.芯片采用0.18μm CMOS工艺实现.测试结果显示,电荷泵的电流为0.3 mA.电流失配率在0.3～1.6 V输出电压范围内小于1%.在1.8 V供电电压下,芯片功耗约为4 mW.实验结果显示,所设计的电路结构实现了充放电电流的匹配,且功耗较低.

A type of improved charge pump for digital audio broadcasting（DAB） radio frequency（RF） tuner is realized.An improved cascode current mirror with operational amplifier is used to enable the charge pump current to be well matched in the core part of the proposed circuit.The self-biasing wide-swing current mirror is adopted in the band-gap of the proposed charge pump to offer a wider range output voltage.The folded operational amplifier in the circuit is realized with folded cascode topology for wider common-mode input range and higher gain.The chip is realized in 0.18 μm complementary metal oxide semiconductor（CMOS） process.Measurement results show that the charge pump current is 0.3 mA.The measured current mismatching can be less than 1% in the output voltage range of 0.3 to 1.6 V.The power consumption is 4 mW under a 1.8 V supply voltage.The experimental results show that the proposed topology structure has realized the match of the charge and discharge current and the lower power consumption.