Load detection circuit and amplifier circuit

The invention provides a load detection circuit and an amplifier circuit to accurately detect the load impedance. The load detection circuit (10) includes a first detection part and a second detection part. The first detection part includes a capacitor (113) and a capacitor (114), and forms capacitive coupling with a signal transmission line (101) connecting an output port of an RF amplifier (20) and a load (ZLD) to output a first signal. The second detection part includes a inductor (111) and a second inductor (112), and forms inductive coupling with the signal transmission line (101) to output a second signal. 本发明提供负载检测电路及放大电路，高精度地检测负载阻抗。负载检测电路(10)具备第一检测部和第二检测部。第一检测部具备电容器(113)及电容器(114)，与将RF放大器(20)的输出端与负载(ZLD)之间连接的信号传输线路(101)进行容性耦合而输出第一信号。第二检测部具备电感器(111)及电感器(112)，与信号传输线路(101)进行感性耦合而输出第二信号。