Current reuse high linearity folding current mirror mixer

Abstract

The invention discloses a current reuse high linearity folding current mirror mixer. A double balanced frequency mixing switch pair is embedded into a current mirror, under common effect of the current mirror and the double balanced switch pair, radio frequency current of a transconductance grade generates an intermediate frequency current signal after frequency conversion, amplitude is consistent with the radio frequency current of the transconductance level, and output voltage is formed on a load resistor. According to the structure based on the current mirror, linearity deterioration of a traditional foldable Gilbert mixer caused by cascade is avoided, simultaneously, input and output static bias current of the current mirror are reused, and an inductance capacitor parallel network is used to realize isolation of a radiofrequency signal. According to the series connected gate tube, on one hand, isolation of an output terminal intermediate frequency signal from a radio frequency transconductance grade output terminal is realized, on the other hand, voltage fluctuation of a current mirror output terminal is stabilized, and accuracy of current mirror duplication is raised. The input and output static bias current of the current mirror is injected to the transconductance grade, current utilization efficiency is raised, and power consumption is reduced.

Description

technical field [0001] The invention relates to a folded current mirror mixer with high linearity for current multiplexing, which adopts the structure of double-balanced switch pairs embedded in the current mirror and the technique of static bias current multiplexing. Background technique [0002] In the RF signal receiving chain, the role of the mixer is to down-convert the input RF signal to an intermediate frequency or baseband for processing by subsequent modules. Considering the entire receiving chain, the mixer should have a high conversion gain to suppress the impact of the noise of the subsequent intermediate frequency amplifier circuit and filter circuit on the noise figure of the entire receiving chain. In addition, the mixer itself should have a lower noise figure than the IF module to relieve the design pressure of the low-noise amplifier. With the application of multi-carrier technology and complex modulation technology in wireless communication more and more, ...

AI Technical Summary

Problems solved by technology

However, due to the limited output impedance and parasitic capacitance of the transconductance transistor, there is a shunt phenomenon of RF current between the transconductance stage and the local oscillator stage

The entire folded mixer can be regarded as a cascade of the transconductance stage, the local oscillator stage and the load stage. According to the linearity cascade formula, the linearity of the entire mixer is deteriorated

This is also the main reason why the linearity of the folded structure is not high

[0004] At the same time, the large transconductance required by the input transconductance stage can only be achieved by increasing the bias current, and the current mirror replication makes the output stage have the same large bias current as the input transconductance stage

The high bias current of the output stage does not provide an effective boost to the circuit performance, so it is wasted

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