Radio-frequency front-end circuit with single-ended input differential output applied to ultra-wideband system

Abstract

The invention belongs to the technical field of integrated circuits of a radio-frequency wireless receiver, and in particular relates to a radio-frequency front-end circuit with single-ended input differential output applied to an ultra-wideband system. The radio-frequency front-end circuit consists of a low noise amplifier (LNA) and an orthogonal mixer, wherein the LNA has a single-ended input differential output structure and consists of two stages so as to adapt to a larger input signal range required by the ultra-wideband system; the orthogonal mixer consists of an I path and a Q path, and the two paths share an input amplifying tube; the mixer adopts a current injection technique and a current injection tube is used as part of the input amplifying tube so as to improve the performance of the mixer; and the LNA and the mixer are connected with each other through a unit gain buffer so as to reduce the influence of large input capacitance of the mixer on the load of the LNA. The radio-frequency front-end circuit has the advantages of simple structure, variable gain, low power consumption, wide using band, small chip area, reduction in the use of an off-chip element, and contribution to realizing singlechip integration.

Description

technical field [0001] The invention belongs to the technical field of radio frequency wireless receiver integrated circuits, and specifically relates to a radio frequency front-end circuit (RF front-end ). Background technique [0002] In recent years, with the rapid development of various mobile communication systems and wireless data transmission technologies such as IEEE802.11a / b / g, WLAN, UWB, etc., the demand for high-performance radio frequency signal receivers is also increasing. The front-end module in the receiver includes a low-noise amplifier and a mixer, which are respectively responsible for amplifying and down-mixing the received weak signal to the low frequency band, and then handing it over to the baseband part of the subsequent stage for filtering and amplification. Since the carrier frequency of the UWB standard data transmission technology is relatively high and the signal bandwidth used is relatively large, the radio frequency receiver needs to amplify a...

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Problems solved by technology

[0003] For traditional radio frequency receivers, a low-noise amplifier (LNA) with a differential structure is generally connected to a mixer with a differential structure (Mixer) to form a front-end circuit with differential input and differential output, so that when the front-end circuit is connected to the antenna, It is necessary to add an additional off-chip single-to-dual device, namely balun, which will introduce a large loss and is not conducive to the realization of single-chip integration; another traditional RF receiver is a low-noise amplifier with single-ended input and single-ended output As the first stage, an on-chip single-to-dual circuit is cascaded, and finally a down-mixer is cascaded to form the front-end circuit. Such circuits are not good at suppressing noise from power supplies, substrates, and other sources of interference. Great, because the first-stage LNA uses a single-ended structure, which cannot convert noise from the power supply, substrate, and other interference into common-mode noise to eliminate it like a differential structure

For the cascading of the two, the traditional structure is to connect the LNA and the Mixer directly or through a DC blocking capacitor, and usually due to the large input capacitance of the Mixer, the performance of the LNA will be greatly affected by the subsequent stage.

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