Stmicroelectronics S.a.

Stmicroelectronics France

Stmicroelectronics Razvoj Polprevodnikov D.o.o.

St-ericsson Sa

Stmicroelectronics (grenoble 2) Sas

Marc Houdebine

Sebastien Dedieu

Maksimiljan Stiglic

Florent Sibille

Sébastien Dedieu

Laurent Jean Garcia

Nejc Suhadolnik

Kosta Kovacic

Sebastien Rieubon

Jerome Lajoinie

Julien Kieffer

Gregoire Montjaux

A device is configured to receive a first carrier signal, and deliver a second carrier signal, and has a phase-locked loop including a first domain including an oscillator configured to generate a signal at a given frequency, and a circuit configured to generate information representative of the frequency of the signal generated by the oscillator, and to generate the second carrier signal and a clock signal, the first domain being clocked by the first carrier signal, a second domain, clocked by the clock signal, including a circuit configured to compare the frequency of the signal generated by the oscillator with the frequency of the first carrier signal and to control the oscillator, a matching circuit configured to transfer information representative of the frequency of the signal generated by the oscillator from the first domain to the second domain.

Device comprising a synchronization circuit for performing near field communication

In one embodiment, an object can communicate contactlessly with a reader using active load modulation. The method includes detecting a sensing magnetic field emitted by the reader, initializing a phase-locked loop of the object, detecting a stopping of the sensing magnetic field emitted by the reader before initializing the phase-locked loop of the object is complete, calibrating an oscillator of the phase-locked loop on the basis of an internal clock of the object, detecting a new sensing magnetic field of the reader after calibrating the oscillator, and implementing the phase-locked loop to adjust the phase of the oscillator after detecting a new sensing magnetic field.

Contactless communication method between an object and a reader using active load modulation

A clock generator circuit includes an oscillator circuit coupled to a bias circuit. The bias circuit includes a current mirror, third and fourth transistors, and a cascode transistor. The current mirror includes a reference transistor and a set of copy transistors that are programmable. The third transistor has a source connected to a cold spot, a drain and a gate connected to this drain. The fourth transistor has a source connected to the drain of the third transistor, a drain, and a gate connected to that drain. The cascode transistor has a source connected to a drain of at least one of the copy transistors, a drain, and a gate connected to the gate of the fourth transistor. The gates of the fourth transistor and the cascode transistor are thicker than the gates of the reference transistor, each copy transistor, and the third transistor.

Clock generator circuit for near field communication device

An embodiment device comprises a phase locked loop and a frequency locked loop having in common the same controlled oscillator. The device is firstly placed in the card emulation mode at the beginning of a communication between the contactless communication device and a contactless reader, the firstly placing comprising synchronizing within the contactless device, an ALM carrier frequency with a reader carrier frequency by operating at least the phase locked loop, and upon reception by the contactless communication device of an indication sent by the reader indicating a further communication in a peer to peer mode with the reader, the device is secondly placed in the peer to peer mode, the secondly placing including deactivating the phase locked loop and operating the frequency locked loop with a reference clock signal and a frequency set point depending on the reader carrier frequency and the frequency of the reference clock signal.

Contactless communication device mode switching management

An embodiment near-field communication device using active load modulation, in card emulation mode and intended to communicate with a reader, comprises a digital phase-locked loop configured to generate a carrier signal, having an oscillator configured to generate the carrier signal in a manner controlled by an analog control signal, a feedback circuit configured to generate a digital control signal, a digital-to-analog converter configured to convert the digital control signal into the analog control signal, and an integrator assembly configured to integrate the analog control signal.

NFC device emulated in card mode comprising a digital phase locked loop, and corresponding communication method

A transponder communicates with a reader using active load modulation. The transponder includes a digital phase locked loop (DPLL), which, in operation, generates an active load modulation (ALM) carrier clock synchronized to carrier clock of the reader. Between transmission of data frames, the DPLL is placed in a lock mode of operation in which a feedback loop of the DPLL is closed. Within a transmitted data frame having a duration, the DPLL is placed, for the duration of the transmitted data frame, in a hold mode of operation in which the feedback loop is opened. A phase of the ALM carrier clock is adjusted at least once during the duration of the transmitted data frame.

Method for synchronizing an active load modulation clock within a transponder, and corresponding transponder

Data frames, including bursts of an active load modulation (ALM) carrier signal generated from a modulation of an underlying carrier, are transmitted from an object to a reader. Synchronizing a reader carrier signal and the ALM carrier signal includes: prior to transmission of each data frame and between some of the bursts of the ALM carrier signal of each data frame, performing a closed-loop control of an output signal of a main oscillator onto a phase and a frequency of the reader carrier signal; estimating a ratio between a frequency of the output signal of the main oscillator and a frequency of a reference signal produced by a reference oscillator; and during each burst of the ALM carrier signal of each data frame, performing a closed-loop control in frequency only of the output signal of the main oscillator onto the reference frequency of the reference signal corrected by the ratio.

Synchronization between a reader and an object in contactless communication with the reader by active load modulation

A method includes a) counting whole periods of a signal during a first period of a reference signal, b) repeating step a) for each period of the reference signal until a first duration is equal to a first quantity of periods of the reference signal, and c) determining a first average of the whole periods. The method also includes repeating at least one of steps a) to c) and at each repetition shifting a start of the counting of step a) by at least one period of the reference signal, and in steps b) and c) accounting for whole periods of the signal already counted during the at least one preceding group of steps a) and b). The method includes determining a second average of the first averages, and determining the frequency of the signal from the second average and the frequency of the reference signal.

Method and device for measuring the frequency of a signal

A method of contactless communication can be performed between an object and a reader using active load modulation. A synchronization process is performed between a first carrier signal transmitted by the reader and having a reference frequency, and a second carrier signal extracted from an output signal of a controlled oscillator of a digital phase-locked loop of the object. In the synchronization process, as long as a locking of the loop has not been detected, the frequency of the output signal of the oscillator is latched on a frequency that is a multiple of the reference frequency. Once the locking has been detected, the latching continues while controlling the oscillator with a second control signal generated from a second value obtained.

Synchronization between an object and a reader contactlessly communicating by active load modulation

In some embodiments, a phase locked loop includes a voltage-controlled oscillator whose output is fed back to a first input of a phase comparator via a fractional divider controlled by a delta-sigma modulator. The method of doubling the frequency of the initial reference signal of the phase locked loop involves generating, from the initial reference signal and the output signal furnished by the voltage-controlled oscillator, a secondary reference signal having edges of a first type synchronized with each of the rising and falling edges of the initial reference signal and edges of a second type between the edges of the first type, and a furnishing of the secondary reference signal at a second input of the phase comparator operating on the edges of the first type.

Method and device for doubling the frequency of a reference signal of a phase locked loop

A method can be used for contactless communication of an object with a reader using active load modulation. A main clock signal is generated within the object. The generating includes a calibration phase and a transmission phase. The calibration phase includes locking an output signal of a controlled main oscillator onto a phase and frequency of a secondary clock signal received from the reader and estimating a frequency ratio between a frequency of the output signal of the main oscillator and a reference frequency of a reference signal originating from a reference oscillator. The transmission phase includes only frequency-locking the output signal of the main oscillator onto the frequency of the reference signal corrected by the estimated frequency ratio.

Method of contactless communication between an object and a reader by active load modulation

According to embodiments, dual path loop filter circuits are described which have, for example, a single charge pump. The current flow in the DPLF circuit is architected to source, during an injection time period, a first current to the loop filter, sink, also during the injection time period, a second current from the loop filter, wherein the first current has a magnitude of &#x3b1;*I and the second current has a magnitude of &#x3b2;*I, and sink, during a linearization time period, a third current from the loop filter, wherein the third current has a magnitude of (&#x3b1;&#x2212;&#x3b2;)*I.

Double output linearized low-noise charge pump with loop filter area reduction

A phase-locked loop circuit having a comparator that receives a target digital word representative of a non-integer target ratio between a main signal and a reference signal having a reference frequency. The circuit also includes digitally-controlled oscillator coupled to the comparator to deliver an output signal. One return loop is coupled between the output of the oscillator and the comparator. The latter includes a device to generate a digital word representing the non-integer ratio between the period of the reference signal and the period of the output signal, the reference signal and the output signal respectively corresponding to the first and second signal, and the fixed integer part N being equal to the integer part of the target non-integer ratio. The comparator compares the digital word and target digital word. The oscillator adjusts the frequency of the output signal as a function of the result delivered by the comparator.

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Crolles, France

Marc Houdebine