This paper describes the design and performance of a 90 nm CMOS SAW-less receiver with DigRF interface that supports 10 WCDMA bands (I, II, III, IV, V, VI, VIII, IX, X, XI) and 4 GSM bands (GSM850, EGSM900, DCS1800, PCS1900). The receiver is part of a single-chip SAW-less transceiver reference platform IC for mass-market smartphones, which has been designed to meet Category 10 HSDPA (High Speed Downlink Packet Access) requirements. The novel receiver core consists of a single-stage transconductance amplifier (TCA) with large gain control range, a current commutating passive mixer enhanced for automatic on chip IIP2 calibration with 25% duty-cycle LO injection and threshold adjust, and current-input complex Direct Coupled Filter (DCF). The low noise TCAs are designed without inductive loads to save area. A self-contained on chip automatic IIP2 calibration system with algorithm routine, implemented in firmware, is used to optimize IIP2 performance. This topology eliminates the external LNA, inter-stage SAW filter and transimpedance amplifier (TZA) in conventional WCDMA designs and results in current drain and die area savings as well as improved noise. The 25% duty-cycle LO injection, with threshold adjustment, into a current driven passive double-balanced mixer results in 3 dB additional gain, lower noise figure and lower intermodulation distortion. Large signal blocking and 1/f noise performance are improved significantly by eliminating the 0 and 180deg LO signal crossover at the mixer. The full receiver achieves 2.2 dB/2.39 dB simplex/duplex NF (with - 24.5 dBm TX leakage), > 90 dBm complex two-tone IIP2, 60 dB gain and - 1/+ 5 dBm half/full-duplex image IIP3. The receiver core consumes only 15.1 mA from a 1.5 V supply.

A Single–Chip 10-Band WCDMA/HSDPA 4-Band GSM/EDGE SAW-less CMOS Receiver With DigRF 3G Interface and ${+}$ 90 dBm IIP2

Apparatus and methods for envelope tracking are disclosed. In one embodiment, a power amplifier system including a power amplifier and an envelope tracker is provided. The power amplifier is configured to amplify a radio frequency (RF) signal, and the envelope tracker is configured to control a supply voltage of the power amplifier using an envelope of the RF signal. The envelope tracker includes a buck converter for generating a buck voltage from a battery voltage and a digital-to-analog conversion (DAC) module for adjusting the buck voltage based on the envelope of the RF signal to generate the supply voltage for the power amplifier.

Apparatus and methods for envelope tracking

The present invention provides for an improved scanning process having microwave arrays comprised of microwave transmitters in radiographic alignment with microwave receivers. The microwave array emits controllably directed microwave radiation toward an object under inspection. The object under inspection absorbs radiation in a manner dependent upon its metal content. The microwave radiation absorption can be used to generate a measurement of metal content. The measurement, in turn, can be used to calculate at least a portion of the volume and shape of the object under inspection. The measurement can be compared to a plurality of predefined threats. The microwave screening system is used in combination with other screening technologies, such as NQR-based screening, X-ray transmission based screening, X-ray scattered based screening, or Computed Tomography based screening.

Methods and systems for the rapid detection of concealed objects

Properties of the current-driven passive mixer are explored to maximize its performance in a zero-IF receiver. Since there is no reverse isolation between the RF and baseband sides of the mixer, the mixer reflects the baseband impedance to the RF and vice versa through simple frequency shifting. It is also shown that in an IQ down-conversion system the lack of reverse isolation causes a mutual interaction between the two quadrature mixers, which results in different high- and low-side conversion gains, and unexpected IIP2 and IIP3 values. With a thorough and accurate mathematical analysis it is shown how to design this mixer and its current buffer, and how to size components to get the best linearity, conversion gain and noise figure while alleviating the IQ cross-talk problem.

Analysis and Optimization of Current-Driven Passive Mixers in Narrowband Direct-Conversion Receivers

The present invention is directed to perform fine low-voltage control without largely increasing the circuit layout area in a low-power consumption structure. In the case of shifting a region to a low-speed mode, a system controller outputs a request signal and an enable signal to a power switch controller and a low-power drive circuit, respectively, to turn off a power switch and to perform a control so that the voltage level of a virtual reference potential becomes about 0.2 V to about 0.3V. The region operates on voltages between a power supply voltage and a virtual reference potential, so that it is controlled in the low-speed mode.

Semiconductor Integrated Circuit Device

An integrated circuit is described for providing a power supply to a radio frequency (RF) power amplifier (PA). The integrated circuit includes a low-frequency power supply path including a switching regulator and a high-frequency power supply path arranged to regulate an output voltage of a combined power supply at an output port of the integrated circuit for coupling to a load. The combined power supply is provided by the low-frequency power supply path and high-frequency power supply path. The high-frequency power supply path includes: an amplifier including a voltage feedback and arranged to drive a power supply signal on the high-frequency power supply path; and a capacitor operably coupled to the output of the amplifier and arranged to perform dc level shifting of the power supply signal.

Integrated circuit wireless communication unit and method for providing a power supply

With growing WCDMA adoption there is a strong demand to reduce the cost of WCDMA terminals. Contributing to the relatively high WCDMA terminal cost is the low integration of today's WCDMA radios. Since WCDMA is an FDD system the transmitter and receiver are on simultaneously. A duplexer is used to isolate the receiver from the transmit signal but the isolation of small low-cost duplexers is limited, with a guaranteed isolation at the TX frequency of not more than 52dB. For a Class-3 terminal with 2dB TX path loss due to duplexer and switch, the power at the PA output is +26dBm and the receiver will see a TX leakage of up to -26dBm. Today's state-of- the-art WCDMA transceivers deal with the TX blocking problem by using an external TX SAW filter to eliminate TX noise in the RX band and an external LNA and RX SAW filter to achieve sufficient RX linearity. A typical tri-band transceiver requires 6 SAW filters and 3 LNAs. The tri-band WCDMA transceiver presented here eliminates all external SAW filters and LNAs and achieves excellent performance with standard low-cost duplexers.

Single-Chip Tri-Band WCDMA/HSDPA Transceiver without External SAW Filters and with Integrated TX Power Control

A frequency agile voltage controlled oscillator is provided in which amplitude control is performed by digitally controlling the current supplied to the oscillator from a current source (10). The use of digital control means that phase noise performance of the oscillator is not degraded by the introduction of noise from the current source controller.

Voltage controlled oscillator having improved phase noise

High-data-rate wireless technologies such as HSUPA and LTE are power-hungry because of the fundamental correlation between data rate and transmit power. Furthermore, the high peak-to-average power ratio (PAPR) of the modulated signals causes a degradation in PA efficiency, since the supply voltage of the PA must be high enough to provide the peak output voltage without loss of linearity. Envelope tracking modulators have been proposed to improve the efficiency and linearity of transmitters. Modulators using multiple input voltages have been shown to improve efficiency, but generating multiple supplies imposes substantial overhead. Several recent works have demonstrated a hybrid modulator, combining the output current of a buck output stage with that of a linear amplifier. The hybrid modulator has the notable advantage that the low-frequency power (which constitutes the majority of power, even in high-PAPR scenarios) can be provided through the efficient buck stage. The inherently less efficient linear amplifier stage needs only to supply the high-frequency power. The efficiency of hybrid modulators degrades at moderate power levels, when the ac amplitude is much less than the supply voltage of the linear amplifier. At low power levels, the power savings afforded by the modulator do not offset its own quiescent current, resulting in a lower efficiency than can be achieved using a fixed-drain, average-power-tracking (FD-APT) supply.

An AC-coupled hybrid envelope modulator for HSUPA transmitters with 80% modulator efficiency

An integrated circuit for providing a differential interface for an envelope tracking signal is described. The integrated circuit includes a subtraction module having a first input for receiving a digital envelope tracking signal and a second input for receiving a second signal, wherein the subtraction module is arranged to subtract the second signal from the digital envelope tracking signal and produce an envelope tracking signal with a reduced average direct current (DC) component; a digital-to-analog converter (DAC) arranged to receive the envelope tracking signal with the reduced average DC component and produce a differential analog version thereof; and a modulator operably coupled to a differential output of the DAC, wherein the modulator comprises a DC input point arranged to insert a DC component into the differential analog version of the envelope tracking signal.

Paul Fowers

Papers

Integrated circuit wireless communication unit and method for providing a power supply

Single-Chip Tri-Band WCDMA/HSDPA Transceiver without External SAW Filters and with Integrated TX Power Control

Voltage controlled oscillator having improved phase noise

An AC-coupled hybrid envelope modulator for HSUPA transmitters with 80% modulator efficiency

Integrated circuit, wireless communication unit and method for a differential interface for an envelope tracking signal