Radio-frequency power amplifier power control circuit utilizing NMOS (N-channel metal oxide semiconductor field-effect transistor) regulating tube

Abstract

The invention discloses a radio-frequency power amplifier power control circuit compact in square. In a radio frequency power amplifier controlled by collector electrode power, output voltage of a collector electrode directly controls output voltage amplitude of radio frequency. A PMOS (P-channel metal-oxide-semiconductor field-effect transistor) regulating tube normally used for power control is replaced by an NMOS (N-channel metal oxide semiconductor field-effect transistor) regulating tube, and driving voltage of the NMOS regulating tube is boosted by a boost-type charge pump circuit. Range of control voltage can be enlarged by boosting the driving voltage of the NMOS regulating tube. By utilizing the NMOS regulating tube, output of a power control circuit is low in impedance, a compensation circuit is simple, and stable voltage output can be realized without externally connecting large output capacitance. Secondly, under the same condition with identical breakover capability, the square of the NMOS regulating tube is smaller than that of the PMOS regulating tube, so that area of a chip is saved, and design cost is reduced.

Description

technical field [0001] The invention relates to a method for reducing the area of ​​a power control circuit of a radio frequency power amplifier. technical background [0002] In today's mobile communication system, the transmission power of the handheld mobile terminal needs to be dynamically controlled according to the distance from the base station or the strength of the signal. When using constant envelope modulation, RF power amplifiers generally work in saturation to obtain the highest power efficiency. The power control of the power amplifier in the saturated state is generally realized by controlling the power supply voltage of the power amplifier, because theoretically the saturated output voltage amplitude of the power amplifier is proportional to the power amplifier power supply voltage amplitude. Usually, the collector power control method is adopted in the design, that is, the output power is controlled by controlling the collector voltage of the power amplifie...

AI Technical Summary

Problems solved by technology

[0003] The problem solved by the present invention is to overcome a series of problems caused by using a PMOS adjustment tube in the power control circuit of the radio frequency power amplifier

Overcome the disadvantage of low output voltage of NMOS tube

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