Transconductance-enhancing passive frequency mixer

Abstract

The invention discloses a transconductance-enhancing passive frequency mixer, which comprises a mixing stage and a biasing circuit, and further comprises a transconductance stage with a transconductance-enhancing function, a passive mixing switch pair and an enhanced load output stage, wherein the transconductance stage with a transconductance-enhancing function transforms an input radio-frequency voltage into a radio-frequency current; and frequency mixing of the radio-frequency current is achieved through the double-balance mixing switch pair, and the current after frequency mixing is transformed into a mid-frequency voltage for output through the transconductance-enhanced load output stage. As the transconductance stage uses a pre-amplifying transconductance-enhancing structure, transconductance is greatly enhanced, thus the same transconductance value can be achieved at a lower bias current, and an output mid-frequency current signal is generated after the radio-frequency current is modulated through the mixing stage. Voltage output is generated through a transresistance amplifier, and finally the mid-frequency voltage signal is obtained. As the transresistance amplifier uses a transconductance-enhancing structure, input impedance is reduced, and current utilization efficiency and port isolation are improved. The transconductance-enhancing passive frequency mixer provided by the invention has the characteristics of low power consumption, high conversion gain, good port isolation and the like.

Description

technical field [0001] The invention relates to a transconductance enhanced passive mixer, which belongs to the technical field of mixers. Background technique [0002] The indicators of the traditional Gilbert mixer are relatively balanced, and the work is reliable, and the port isolation is good. However, with the continuous improvement of the monolithic requirements of radio frequency receivers and the continuous progress of radio frequency technology, in many practical applications, the performance of traditional Gilbert mixers is sometimes difficult to meet the current needs. For example, when the mixing stage adopts an active mixing structure, in the zero-IF receiver structure, its flicker noise will have a certain impact, and if a passive mixing structure can be used, since the passive mixer has no quiescent current, its Flicker noise is also greatly reduced, and passive mixers are generally more linear than active mixers. [0003] In the classic frequency mixing st...

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Problems solved by technology

[0003] In the classic frequency mixing structure, when the RF voltage is converted into RF current in the transconductance stage, since the signal received by the receiver is generally small, and the traditional transconductance is generally only the transconductance value of the input transistor, at low bias current The transconductance value is limited, and the conversion gain is low

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