Direct conversion device with compensation means for a transmission path of a wireless communication equipment

Abstract

A conversion device (CD) is dedicated to conversion of baseband analog I / Q input signals into RF signals in a transmitting path of a wireless communication equipment. This device (CD) comprises i) first (PP1) and second (PP2) processing paths each comprising i1) an input node (IN1, IN2) receiving an input signal (I / Q), i2) an input path (IP1, IP2) connected to the input node and delivering an input current representative of the input signal (I / Q), i3) an amplification means (A1, A2) having first and second inputs fed with the input current and a common-mode current and outputting an amplified signal, and i4) a transconductor (T1, T2) delivering first and second currents from the amplified signal, the first current feeding a negative feedback path connected to the first input of the amplification means and being essentially equal to the input current, and the second current being a chosen scaled copy of the first current and representative of a voltage difference between the input signals (I / Q), H) a common-mode input path (CIP) connected to the input nodes (IN1, IN2) and delivering the common-mode current from the input signals (I / Q) to feed the second input of each amplification means (A1, A2), and iii) a switch core (SC) for mixing the second current delivered by a chosen one of the transconductors (T1, T2) with a local oscillator RF carrier to deliver output RF signals representative of the input signals (I / Q).

Description

technical field [0001] The present invention relates to the transmit path of a wireless communication device, and more particularly to radio frequency (RF) conversion of baseband analog I / Q signals in the transmit path with a direct conversion architecture. [0002] Here, "I signal" represents an in-phase component signal, and "Q signal" represents a quadrature component signal. Background technique [0003] In some conversion devices with direct conversion architectures, the input baseband signal in the form of a differential analog I / Q voltage is converted to an RF signal by multiplying it by a sine and cosine RF carrier, which is composed of a pair of Generated by the local oscillator (LO) in the switch core of the quadrature mixer. [0004] This type of direct conversion can produce RF signals including phase and amplitude information, suitable for a wide range of radio standards, such as GSM, EDGE, WCDMA and OFDM. This type of direct conversion results in a simplified...

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Problems solved by technology

For example, larger matched transistor sizes can be chosen i) to reduce random lithography errors, which then reduce mismatch, and ii) to increase device area and reduce 1 / f noise contribution, but at the same time must choose smaller matching Transistor size to reduce parasitic capacitance and thus increase the open-loop gain x bandwidth product

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