Wireless transmission device in which transmission output is controlled in feedback control
View Patent ↗A wireless transmission device includes a RF power amplification section for amplifying a transmit RF signal and outputting the amplified signal to a transmission antenna, a detector section, and a control section. The RF power amplification section includes a plurality of stages of amplification, the transmit RF signal is input to an input of a first one of the plurality of stages of amplification, and an output of a last one of the plurality of stages of amplification is output to the transmission antenna. The detector section includes a plurality of detectors provided so as to correspond to the plurality of stages of amplification, each for detecting an input level of a corresponding one of the stages of amplification, and a synthesizer for synthesizing together detection outputs from the plurality of detectors. The control section controls, in a feedback control, an output level of the RF power amplification section based on an output level of the synthesizer.
1. A wireless transmission device, comprising:
a RF power amplification section for amplifying a transmit RF (Radio Frequency) signal and outputting the amplified signal to a transmission antenna;
a detector section; and
a control section, wherein:
the RF power amplification section includes a plurality of stages of amplification;
the transmit RF signal is input to an input of a first one of the plurality of stages of amplification;
an output of a last one of the plurality of stages of amplification is output to the transmission antenna;
the detector section includes:
a plurality of detectors provided so as to correspond to the plurality of stages of amplification, each for detecting an input level of a corresponding one of the stages of amplification; and
a synthesizer for synthesizing together detection outputs from the plurality of detectors; and
the control section controls, in a feedback control, an output level of the RF power amplification section based on an output level of the synthesizer.
2. The wireless transmission device of claim 1 , wherein each of the plurality of detectors includes:
a peak hold detector section for detecting a peak voltage of a signal that is input to a corresponding one of the plurality of stages of amplification;
a reference signal section for generating a reference signal of a predetermined level; and
a comparator for outputting a current based on a comparison between a detection output of the peak hold detector section and the reference signal,
wherein the synthesizer includes a current-voltage converter for converting a sum of output currents from the comparators of the plurality of detectors to a voltage.
3. The wireless transmission device of claim 1 , wherein the RF power amplification section further includes at least one inter-stage matching network inserted between the plurality of stages of amplification.
4. The wireless transmission device of claim 2 , wherein each of the plurality of detectors further includes:
a first low-pass filter provided between an output of the peak hold detector section and an input of the comparator; and
a second low-pass filter provided between an output of the reference signal section and the input of the comparator.
5. The wireless transmission device of claim 1 , wherein the detector section and the RF power amplification section each employ a CMOS (Complementary Metal-Oxide Semiconductor) configuration.