Em Microelectronic-marin Sa

Em(us) Design, Inc

Em Microelectronics-us, Inc

Kevin Scott Buescher

James Harold Lauffenburger

Gil Afriat

Robert Rudolf Rotzoll

Lawrence Bieber

Michel Willemin

John William Arachtingi

Nicolas Chauvin

Sylvain Grosjean

André Grandjean

Matthijs Pardoen

Marc Morin

Michal Prokes

Jiri Buryanec

James Harlod Lauffenburger

Milos Becvar

Larry Bieber

James Harold Lauffenberger

A rectifier circuit () for a passive RFID circuit (), including: a first rectifier stage () having a positive stage input () connectable to a first antenna port () and a negative stage input () connectable to a second antenna port (); a first rectifying unit () connected to the positive stage input () and to a positive stage output (); a second rectifying unit () connected to the negative stage input () and to a negative stage output (); and a trimming capacitor () connected to the positive stage input () and to the negative stage input (). The trimming capacitor () is electronically switchable to a first capacitance and to a second capacitance, and a voltage dependent variable capacitor () is connected to the positive stage input () and to the negative stage input ().

Rectifier circuit for an RFID tag

A detector circuit being part of a Radio Frequency Identification (RFID) device is provided, including: a bias current generator circuit configured to generate an output bias current that is proportional to the square of a temperature-dependent input current; first and second Field-Effect Transistor (FET) devices; at least one of the first and the second FET devices is biased by means of the output bias current of the bias current generator circuit so that FET device(s) operates in a sub-threshold region; an incoming Radio Frequency (RF) signal being coupled into at least one of the first and the second FET devices; a current source configured to generate a variable threshold current; and a comparator configured to determine, based on the variable threshold current and the incoming RF signal, whether a value of the incoming RF signal exceeds a threshold value.

Detector circuit for an RFID-device

The present invention concerns a programmable power amplifier comprising: an amplifier core transistor circuit connected to an amplifier output node; a switch connected to the amplifier core transistor circuit, the switch being configured to switch on and off the amplifier core transistor circuit; and a feedback circuit of the amplifier core transistor circuit. The feedback circuit comprises a digital-to-analog converter and an operational amplifier having a first input node configured to receive a first reference signal; a second input node connected to the digital-to-analog converter; and an output node for outputting an operational amplifier output signal and connected to the amplifier core transistor circuit for controlling the amount of current flowing in the amplifier core transistor circuit. The digital-to-analog converter has a programmable resistance value for controlling the resistance of the digital-to-analog converter to thereby adjust a digital-to-analog converter output signal fed to the second input node of the operational amplifier for controlling an amplifier output signal at the amplifier output node.

Programmable power amplifier

A method for improving threshold accuracy in an RFID-device through offset cancellation, and including the steps of providing a comparator including a first and a second amplifiers, providing a current output digital-to-analogue converter, AC-coupling in an RF-signal into the detector circuit, during a first phase, applying a signal based on the RF-signal into the first amplifier while a current of the DAC is set to zero, and applying a current of the DAC into the second amplifier while a signal based on the RF-signal is set to zero, during a second phase, applying the current of the DAC into the first amplifier while the signal based on the RF-signal is set to zero, and applying the signal based on the RF-signal into the second amplifier while the current of the DAC is set to zero.

Method for improving threshold accuracy in an RFID-device through offset cancellation

The present invention relates in one aspect to a voltage regulation circuit for an RFID circuit (), the voltage regulation circuit comprising:

Voltage regulation circuit for an RFID circuit

The present invention relates in one aspect to an auxiliary charge pump for a RFID rectifier, the charge pump, which comprises a first charge pump stage () connected to an input (), a second charge pump stage () connected to the input, a diode clamp () connected to an output (), and a regulating transistor () having a gate connected with an output () of the first charge pump stage and having a source and a drain, wherein one of the source and the drain is coupled to the diode clamp. In further aspects the invention relates to a RFID transponder, to a multistage rectifier and to a rectifier stage comprising such an auxiliary charge pump.

Auxiliary charge pump for a rectifier of an RFID transponder

The present invention relates to a transponder, which comprises an antenna and a multi-stage rectifier. The antenna is connected to an input of the multi-stage rectifier having m rectifier stages, and a shunt limiter is connected to an output of the rectifier and connected to an nstage of the multi-stage rectifier, wherein n&#x3c;m.

RFID transponder with rectifier and voltage limiter

The voltage regulator comprises a regulation loop (), which comprises at least a pass transistor (), a source transistor (), a sensing transistor () and a retention transistor (), and a stability compensation circuit (), which comprises a first MOS resistor () and a second MOS resistor () coupled with the first MOS resistor (). The gate of the second MOS resistor () is coupled to the gate of the pass transistor ().

Low drop-out voltage regulator

The automatic gain control unit for a radiofrequency receiver includes a first current source for charging a storage capacitor by a first current, four comparators for comparing on the lower side an in-phase positive intermediate signal, an in-phase negative intermediate signal, a quarter-phase positive intermediate signal, a quarter-phase intermediate signal with a first reference threshold to a high amplitude level of the intermediate signals. Each comparator controls a MOS transistor connected in series between a second current source and the storage capacitor in order to discharge the storage capacitor when each transistor is in a conductive state. A bi-stable trigger element is connected to the storage capacitor and to provide an AGC signal depending on the voltage level on the storage capacitor for attenuating or not the gain of the low noise amplifier or of a mixer unit amplifier of the receiver.

Automatic gain control unit for a low power receiver or transceiver

A method performs a comparison of input signals in a window comparator circuit. In a first phase, input, ground and offset voltages are stored on capacitors. A comparison is performed between a first adapted input voltage and a second adapted input voltage added to an adapted offset voltage, to provide a first output signal. In a second phase, the voltages are stored on the capacitors in a different manner. A comparison is performed between the first adapted input voltage added to the adapted offset voltage and the second adapted input voltage, to provide a second output signal. Finally, a control of the state of the output signals is performed to determine if the comparison is in a low or high state if the output signals have a same low or high output level, or in an intermediate state if the output signals have a different output level.

Method for performing a tri-state comparison of two input signals in a window comparator circuit, and window comparator circuit for implementing the method

A method for measuring relative motion between an illuminated portion of a surface and an optical sensing device comprising a coherent light source and a photodetector device comprising an array of pixels and comparators for extracting motion features. The method includes the steps (a)-(d). Step (a) includes illuminating with the coherent light source the surface portion at a determined flash rate. Step (b) includes detecting, using the array of pixels a speckled light intensity pattern of the illuminated portion of the surface for each flash. Step (c) includes extracting edge direction data of two different types from the detected speckled light intensity patterns. Step (d) includes measuring relative motion between the optical sensing device and the illuminated portion of the surface based on extracted edge direction data. The step of extracting edge direction data further includes a preliminary step of introducing a selecting factor, which promotes detection of one type of edge direction data rather than another type.

Optimization of statistical movement measurement for optical mouse, with particular application to laser-illuminated surfaces

A power amplifier circuit can be linked to an antenna arrangement of a communication system for transmission of ASK RF data signals. The power amplifier circuit includes an amplifier core with several cascode amplifier cells in parallel. Each cascode amplifier cell is composed of three NMOS transistors in triode mounting between an output terminal connected to the antenna arrangement, and an earth terminal. A first transistor of each cascode amplifier cell is controlled by a carrier frequency signal, whereas a second transistor of each cascode amplifier cell is controlled by a smoothing control loop in order to modulate data to be transmitted on carrier frequency by amplitude shift keying. The smoothing control loop is provided for generating an increasing gate voltage for the second transistors on the basis of an increasing current ramp from a first minimum current value to a second maximum current value during a '0' to '1' data transition. The smoothing control loop is provided for generating a decreasing gate voltage for the second transistors on the basis of a decreasing current ramp from the second maximum current value to the first minimum current value during a &#x201c;1&#x201d; to &#x201c;0&#x201d; data transition for shaping the envelope of ASK RF data signals to be transmitted.

Power amplifier circuit with means for tuning wave shape of ASK RF signal envelope, and method for implementing the power amplifier circuit

It is described a method for measuring the movement of an optical pointing device on a work surface, which includes a pixel photo-detector array to pick-up reflected light on the work surface, a window comparator array receiving pixel voltages and providing comparison signals to a processing circuit. Light intensity between neighboring pixels is compared to determine edge direction data, which includes a positive edge for a first pixel voltage smaller than a second pixel voltage by more than a half of a window voltage, a no-edge, with the difference between the pixel voltages smaller than the half of the window voltage, and a negative edge, for which the first pixel voltage is greater than the second pixel voltage by more than the half of the window voltage. Two edge direction data from two successive flash are compared to determine the relative motion of the pointing device on the work surface.

Method for measuring the movement of an optical pointing device on a work surface

The invention concerns an optical pointing device comprising a coherent light source for illuminating a surface portion with radiation, a driver of the coherent light source for controlling coherent light emissions, a photodetector device responsive to radiation reflected from the illuminated surface portion, processing means for determining, based on the photodetector device response, a measurement of relative motion between the optical pointing device and the illuminated portion of the surface, wherein the coherent light source driver is a fault-tolerant driver comprising redundant power control means for limiting the output power of coherent light emissions.

Single fault laser driver control for optical mouse

A method for detecting lift from a surface portion of an optical pointing device comprising a coherent light source, a photodetector device including an array of pixels, and extracting motion features including comparators with an adjustable offset value, the method comprising the steps of: (i) illuminating the surface portion with radiation by the coherent light source; (ii) detecting radiation patterns reflected from the illuminated surface portion with the photodetector device; (iii) comparing light intensity between neighbouring pixels in the detected radiation patterns; (iv) extracting motion features as a function of the result of the comparison; (v) counting the total number of motion features extracted; (vi) increasing or decreasing the comparator offset value when the total number of motion features increases or decreases; (vii) comparing the comparator offset value with an offset threshold; (viii) enabling detection of a lift condition if the comparator offset value is lower than the offset threshold.

Growing community of inventors

Colorado Springs, CO, United States of America

Kevin Scott Buescher