基于有源镇流改善射频功率管的热稳定性

Improvement of Thermal Stability of RF Power BJT with Ballast Circuits

提出一种基于有源电路的基极镇流方案,用以解决射频功率晶体管的电流集中和热稳定性问题。采用传感器检测非均匀结温分布,后级相邻触发电路触发功率器件子单元基极和发射极之间的镇流MOS管,通过分流来缓解电流集中,进而完成器件子单元的过温保护。模拟结果表明,该方案可以有效地实现对功率器件的保护,与传统的无源镇流电阻方法相比,改进后的器件具有更优良的增益特性。单个有源镇流电路仅消耗功率6.5 mW,占用面积为2 530μm2。

To improve thermal instability and relieve current convergence in RF power BJT,an active ballast solution based on CMOS circuit was proposed.By detecting the inhomogeneous temperature distributions through distributed temperature sensors,the adjacent ballast circuit was triggered to shunt the base convergence current of the power BJT cell,which provided over-temperature protection for the device.Simulation results validated the effectiveness of the proposed ballast circuit in improving the thermal stability of device.Compared to conventional ballast resistor schemes,the improved devices with ballast circuits exhibited a predominant electrical performance.An individual ballast circuit only consumes 6.5 mW of power,and occupies an additional chip area of 2 530 μm2.