Infineon Technologies Ag

Luigi Grimaldi

Dmytro Cherniak

Fabio Padovan

Giovanni Boi

Matteo Bassi

Thomas Bauernfeind

Andreas Schwarz

Francesco Lombardo

Nicolo Guarducci

Qianqian Ha

Andrew Wightwick

Fabio Versolatto

Alessandro Garghetti

A calibration circuit may include a calibration signal generator configured to receive an oscillator signal provided by an oscillator and generate a calibration signal based on the oscillator signal. The calibration signal may be generated to have a predetermined amplitude. The calibration circuit may include a calibration peak detector configured to detect a peak amplitude of the calibration signal. The calibration circuit may include a logic circuit configured to calibrate a peak detector connected to the oscillator based at least in part on the peak amplitude of the calibration signal.

Peak detector calibration

A digital phase-locked loop (DPLL) may include a delta-sigma modulator (DSM). The DSM may include a delay component configured to perform noise shaping of a quantization error introduced by the DSM. The DSM may include a noise transfer function (NTF) component configured to perform filtering of the quantization error introduced by the DSM. The DSM may include an adjustment transfer function (ATF) component configured to cause the filtering of the quantization error to be applied on top of the noise shaping such that an impact of the NTF component on the noise shaping is reduced.

Delta-sigma modulator with modified quantization error shaping

A digital phase-locked loop (DPLL) circuit includes: a first time-to-digital converter (TDC) and a first digital loop filter (DLF) that are configured to be coupled between a reference clock source and a digitally controlled oscillator (DCO), where the first TDC is configured to, during an acquisition mode, generate a phase error by: receiving a reference clock signal from the reference clock source; receiving a clock signal that is based on an output of the DCO divided by a dividing factor, computing a phase error using the reference clock signal and the clock signal; detecting cycle slipping in the computed phase error; and in response to detecting the cycle slipping, modifying the computed phase error to reduce the impact of cycle slipping on the DPLL circuit; and a first frequency divider circuit configured to generate the clock signal by dividing the output of the DCO by the dividing factor.

Digital coarse locking in digital phase-locked loops

A method of applying digital pre-distortion includes: outputting, by a look-up table, a first table value based on an input digital signal; adding the first table value and the input digital signal to generate a first combined signal comprising a first combined value having a first integer coefficient and a first fractional coefficient; separating the first integer coefficient from the first fractional coefficient to generate a first integer signal representing the first integer coefficient and a first fractional signal representing the first fractional coefficient; generating a delta-sigma modulated signal based on the first fractional signal; converting, by a first digital-to-analog, a first digital signal into a first analog signal, wherein the first digital signal is representative of the first integer signal; and converting, by a second DAC, a second digital signal into a second analog signal, wherein the second digital signal is representative of the delta-sigma modulated signal.

Delta-sigmal modulator-based multi-rate digital-to-analog converter with digital pre-distortion

A dynamic element matching (DEM) encoder is provided that converts an N-bit digital codeword into a pattern of 1-bit values. The DEM encoder includes a binary switching tree that includes plurality of switching blocks interconnected between an encoder input and a plurality of encoder outputs. The plurality of switching blocks are configured to receive a plurality of first control signals such that each switching block receives a respective first control signal and is independently programmable based on the respective first control signal into a first mode or a second mode. Each switching block includes a splitting circuit programmed into the first mode or the second mode to split a digital input into two digital outputs using either both a first splitting operation and a second splitting operation that is different from the first splitting operation or the first splitting operation over the plurality of sampling intervals.

Programmable dynamic element matching encoder for a digital-to-analog converter (DAC) and method of programming for a plurality of sampling intervals

A digital phase-locked loop (DPLL) may include a time-to-digital converter (TDC) to provide a phase error signal, a frequency-divider to perform frequency division on an output signal to generate a frequency-divided output signal, a delta-sigma-modulator (DSM) to provide a test signal that represents a quantization error of the DSM, and a digital-to-time converter (DTC) to at least partially remove the quantization error from the frequency-divided output signal based on the test signal to generate the feedback signal. The DPLL may include a circuit to cause the DTC to provide a percentage of the quantization error such that the percentage of the quantization error is in the phase error signal, and a TDC calibration component to calibrate the TDC by applying a gain adjustment factor to the TDC. The gain adjustment factor may be based on the test signal and the phase error signal including the percentage of the quantization error.

Time-to-digital converter calibration

In accordance with an embodiment, a method of operating a fractional-N phase locked loop (FN-PLL) includes: dividing a first clock signal using a multi-modulus divider (MMD) based on a modulus control signal to form a frequency-divided clock signal, where the first clock signal is based on an output clock of the PLL; generating the modulus control signal based on a divider control input value using a delta-sigma modulator (DSM); and when a fractional portion of the divider control input value is within a first range of values, and repeatedly removing a first number of clock cycles from the first clock signal before dividing the first clock signal using the MMD, where the first number of clock cycles is a non-integer number of clock cycles.

System and method of FN-PLL with multi modulus divider

An oscillator includes: a first inductor; and a programmable capacitor bank coupled between a first terminal of the first inductor and a second terminal of the first inductor, where the programmable capacitor bank includes a plurality of cells concatenated together, where each cell of the plurality of cells includes a first node, a second node, a third node, a second inductor, and a programmable capacitor, where the second inductor is coupled between the first node and the third node, and the programmable capacitor is coupled between the third node and the second node, where a first inductance of the first inductor is larger than a sum of the inductances of the second inductors of the programmable capacitor bank.

Oscillator with inductor and programmable capacitor bank

A method of operating a phase-locked loop (PLL) having a dynamic element matching (DEM)-driven digitally controlled oscillator (DCO) includes calibrating the PLL, where calibrating the PLL includes opening a loop of the PLL and performing linearity measurements of the DEM-driven DCO when the loop of the PLL is open and when dynamic matching of the DEM-driven DCO is activated, where performing the linearity measurements includes: applying test control words to the DEM-driven DCO to obtain frequencies in a first range of frequencies; and measuring output frequencies of the DEM-driven DCO corresponding to the test control words. Calibrating the PLL further includes calculating calibration information based on the test control words and the measured output frequencies.

Digital phase-locked loop with a dynamic element matching circuit and a digitally controlled oscillator

In accordance with an embodiment, a ring oscillator includes a plurality of stages coupled in a ring configuration, where stage of the plurality of stages has an input node coupled to an output node of a previous stage of the plurality of stages. Each stage of the plurality of stages includes: a ring oscillator transistor having a control node coupled to the input node, and a load path coupled to the output node; a direct injection circuit having a load path coupled between the control node of the ring oscillator transistor and the output node, and a control node coupled to a first oscillator input node; and a tail injection circuit having a load path coupled between the output node and a first power supply node, and a control node coupled to a second oscillator input node.

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Villach, Austria

Luigi Grimaldi