| 摘要 |
PURPOSE: An operation power control circuit of a mobile telecommunication amplifier is provided, which maintains constant efficiency without regard to an output change of the amplifier by controlling an operation voltage level of the amplifier. CONSTITUTION: If an RF signal is inputted through an input port(201), an amplifier(202) supplied with an operation power from a power supply part(203) amplifies the RF signal. Accordingly, an amplified signal of the amplifier is output to an output port(205) through a coupler(206) and an isolator(204) in sequence and then is transmitted to the external through an antenna. The coupler transmits the output signal of the amplifier to the isolator, and samples and transmits a part of the above output signal to a detector(207). And the detector converts a signal transmitted from the coupler into a DC value and then inputs it to a comparator part(208). And the operation voltage from the power supply part is dropped through a resistor(R) and is supplied to the amplifier. The comparator part detects a voltage on both ends of the resistor, and compares a difference value of the both ends voltage of the resistor with the DC value in the detector and then outputs a value corresponding to the comparison result to a control part(209). Thus, the control part maintains a constant voltage level by controlling a level of the operation voltage supplied to the amplifier from the power supply part.
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