用于功率放大器的随温度可调负压偏置电路

Negative Voltage Bias Circuit Adjustable with the Temperature for Power Amplifier Applications

设计了一种应用于GaN功率放大器栅极调制的随温度可调负压偏置电路。电路由电压基准模块、温度传感器模块、比较器阵列以及误差放大器及其对应的功率管与反馈电阻等组成,通过基准电压与温度传感器输出电压的比较,输出数字控制信号到反馈电阻中的可变电阻模块,改变可变电阻阻值进而改变电路输出电压,实现芯片电压随温度可调。电路结构简单、易于实现、应用方便,同时电路中引入了修调电阻结构,极大提高了基准输出精度。电路芯片面积为1.10 mm×0.64 mm,采用0.5μm CMOS工艺进行了流片并完成了后期测试验证。结果表明,芯片可实现输出电压的随温度可调,有效解决了GaN功率放大器在相同的栅极偏置电压下输出功率随温度升高而减小的问题。

A negative voltage bias circuit adjustable with the temperature was designed for the gate modulation of GaN power amplifiers.The circuit consists of a voltage reference module,a temperature sensor module,a comparator array,an error amplifier and its corresponding power transistor and feedback resistors.By comparing the reference voltage with the output voltage of the temperature sensor,a digital control signal is outputted to the variable resistor module in the feedback resistors.The variable resistance is used to change the output voltage of the circuit,and finally the chip voltage is adjusted with the temperature.The structure of the circuit is simple,easy to realize and convenient to apply,and the trim resistor structure was introduced in the circuit,which greatly improved the output reference accuracy.The chip was fabricated in the 0.5 μm CMOS process with an area of 1.10mm×0.64mm and the post-test verification was completed.The test results show that the output voltage of the chip can be adjusted with the temperature,and the problem that the output power of the GaN amplifier decreases with the increase of the temperature under the same gate bias voltage is solved effectively.