Circuit structure utilizing adjustable inductor and improving linearity of power amplifier as well as method

Abstract

The invention discloses a circuit structure which utilizes an adjustable inductor and improves linearity of a power amplifier as well as a method. The circuit structure contains an on-chip transformercoupling input network, a transistor amplifier circuit, an output network, a control and bias generating circuit and an envelope detection circuit; the transistor amplifier circuit is respectively connected with the on-chip transformer coupling input network and the output network; the transistor amplifier circuit is provided with a capacitor-inductor parallel resonance loop as well as a capacitor and the adjustable inductor connected in parallel in the capacitor-inductor parallel resonance loop; and the envelope detection circuit is connected with the control and bias generating circuit, detects an envelope signal of a radio frequency signal of the input network or output network and generates the required bias signal and a control signal for the adjustable inductor. The circuit structure disclosed by the invention realizes dynamic and adjustable low-resistance bias loop by adopting a parallel adjustable LC loop way, AM-AM nonlinearity is improved, and the adjustable inductor eliminates AM-PM nonlinearity; and the circuit structure can be conveniently used in an inter-stage matching and impedance transformer network of a multistage amplifier, and cascade connection of a multistage radio frequency power amplifier can be realized conveniently.

Description

Technical field [0001] The present invention relates to the field of radio frequency power amplifier circuits, in particular to a circuit structure and method that utilizes adjustable inductance and improves the linearity of a power amplifier. Background technique [0002] The radio frequency power amplifier (hereinafter abbreviated as radio frequency power amplifier) ​​is a decisive component that determines the signal and power consumption of the wireless communication transmitter. In order to effectively utilize spectrum resources, non-constant envelope modulation methods are widely used in modern wireless digital communications, which places high requirements on the linearity of radio frequency power amplifiers. [0003] The linearity index of the radio frequency power amplifier can be investigated from two aspects, namely input amplitude-output amplitude characteristic (hereinafter abbreviated as AM-AM characteristic) and input amplitude-output phase characteristic (hereinafte...

AI Technical Summary

Problems solved by technology

The disadvantage of this solution is that the inductor is on the signal path, which is inconvenient to isolate the high-frequency signal and the DC bias signal, and it is expensive to design a low-impedance bias voltage circuit.

However, the impedance of the bias loop itself is too high, which will cause nonlinear effects such as adjacent channel leakage and upper and lower sideband asymmetry of the RF power amplifier.

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