HBT自热效应对功率放大器偏置电路的影响及补偿

Effect of HBT Self-Heating Effect on Bias Circuit for Power Amplifier and Its Compensation

研究了GaAs HBT的自热效应对功率放大器镜像电流源偏置电路性能的影响.HBT自热效应使得这种偏置电路的镜像精度和温度特性变差.利用HBT器件特有的集电极电流热电负反馈理论,通过优化基极偏置电阻的方法,对自热效应进行了有效补偿,偏置电路的电流镜像精度得到有效提高,偏置电流温度漂移由9.5%减小到0.5%.

The effect of GaAs hbt Self-Heating effect on current mirror bias circuit for power amplifier was studied. The effect of self-heating degraded the mirror accuracy and the temperature characteristic of the bias circuit. According to the novel electrical-thermal negative feedback of hbt, a simple method of optimizing a base bias resistor was used to compensate the self-heating in this bias circuit. The results showed that the mirror accuracy was improved and the variation of the bias current as temperature was reduced from 9.5 % to 0. 5 %.