单电源宽带高增益放大器的设计

Design of Broadband High Gain Amplifier with Single Power Supply

采用OPA820作为增益G=5的前级放大器，中间级采用两片THS3001级联各实现G=10的中级放大器，末级采用THS3091作为增益G=2的末级放大器，该放大器在频率为10^-4～20MHz的通频带中可以实现放大增益为60dB。该放大器将系统提供的5V单电源通过升压芯片TPS61087和降压芯片MC34063A产生±18．2V的电压，进而使用可调输出的三端稳压管LM317和LM337得到±5V和±15V的电压，用来给放大器供电。放大器末级输出电压经过精密峰值检波电路可得到信号的峰峰值，经过信号调理后送至A／D转换器ADS1286，通过MSP430单片机进行数据采集后，将相关信息送至液晶屏进行显示。

In this paper, an amplifier is designed. The OPA820 is used as amplifier of first stage gain G = 5, intermediate level is used two pieces of THS3001 cascade to implement intermediate amplifier gain G = 10, lastly by THS3091 is used as gain 2 final amplifier. The amplifier works at a frequency of 10^-4 to 20 MHz bandwidth and achieves amplification gain of 60 dB. At the same time, the system provides a 5 V single power supply through the boosting chip TPS61087, and buck chip MC34063A produces ± 18.2 V voltage and adjustable output of three terminal voltage regulator tube LM317 and LM337 to be ± 5 V and ± 15 V voltages used to supply power to the amplifier. Finally, amplifier output voltage after precision peak detector circuit can get the signal peak, after signal conditioning evacuation the signal is sent to the A/D converter ADS1286 and through MSP430f2274 MCU for data acquisition. All data can eventually be sent to the liquid crystal for display.