采用二重闭环互锁调控技术的BiCMOS VFC

A kind of BiCMOS voltage to frequency converter using double closed-loop interlock and adjustment control technologies

针对主要的压频转换器调控范围窄、线性误差大和静态功耗较高的问题,设计了0.25μmBiCMOS压/频转换器(VFC).电压/电流转换电路(VCC)选用两级套筒式CMOS共源-共栅运放;在VCC和充放电回路、电压检测电路中分别引入负反馈,且二者级连成双重闭环系统;CMOS反馈选通电路和BJT电子开关单元设计成互锁结构,将整个电路构成互锁调控BiCMOS VFC.对所设计的VFC进行了仿真和硬件电路试验.结果表明:在输入电压0～1.0 V范围内,理想输出频率线性调控范围为0～60 MHz,实际范围约为100 Hz～58.5 MHz,线性度误差低于1%;整个电路静态功耗仅为230μW,虽比CMOS VFC略高一些,但带宽、线性度和抗干扰能力等性能却得以改善,因此适用于低压、高精度调控的远程信号测量系统.

To solve the problems of narrow adjustment control range,large linearity error and high power consumption of current voltage to frequency converter（VFC）,a kind of 0.25 μm BiCMOS VFC was designed.Two-stage low voltage cascode operational amplifier was adopted in voltage to current converter（VCC）.Negative feedback was respectively introduced into VCC,charge and discharge circuit and vol-tage testing circuit,which formed two closed-loop systems.BJT electronic switching cell and CMOS feedback gate circuit were linked to form interlock and the whole circuit consisted BiCMOS VFC with adjustment control.The simulation and hardware circuit experiments were carried out.The results show that the ideal linear range of output frequency is 0-60 MHz for a given input voltage range of 0-1.0 V,while the real linear range is 100 Hz-58.5 MHz with the linear error lower than 1%.The power consumption of 230 μW is a litter higher than the same kind CMOS VFC,but the performances of bandwidth,linearity and anti-jamming are greatly improved.The proposed VFC is suitable for low voltage and remote measurement systems with high precision control.