According to the invention, a bandgap reference voltage module unit is connected to a threshold value unit of an amplitude limiting unit to realize the dynamic continuous control on the conductive voltage of the threshold value unit, the output voltage value of the bandgap reference voltage module unit is freely set according to the work needs of a circuit, when the voltage of an antenna end is higher than the sum of the bandgap reverence output voltage value and the threshold value voltage of a serially connected MOS (metal oxide semiconductor) tube, the threshold value unit is conducted to open a grounding access, so charges at the antenna end are output to the ground, the quantity of electric charges of the antenna end is reduced, and the rectified direct current voltage is reduced; when the voltage of the antenna end is smaller than the sum of the bandgap reference output voltage value and the threshold value voltage of serially connected MOS tube, the threshold value unit is cut off to enable the grounding access to be positioned at the cut off state, and the rectifying circuit rectifies all charges of the antenna end into a direct current power supply which is used by a load circuit, so the continuous adjusting function on the amplitude limiting voltage is realized, the amplitude-limited voltage values have continuity and precision and the stability of work voltage values of all circuits is ensured.