Nxp B.v.

Nxp Usa, Inc.

Frederic Benoist

Ulrich Andreas Muehlmann

Srikanth Jagannathan

Stefan Mendel

Radha Srinivasan

Steve Charpentier

Kumar Abhishek

A low voltage differential signaling (LVDS) receiver includes a receiver circuit including first and second inputs coupled to first and second conductive pads, respectively, and an output coupled to an input of a digital controller, and a dummy transmitter circuit including a first input coupled to receive a common mode voltage (VCM) tune signal, a second input coupled to a loopback input signal, a third input coupled to a loopback enable signal, a first output coupled to the first input of the receiver circuit, and a second output coupled to the second input of the receiver circuit. When a test mode of operation is enabled, the digital controller asserts the loopback enable signal, and the dummy transmitter circuit generates a pair of test differential signals based on the VCM tune signal, wherein the VCM tune signal varies to test the LVDS receiver over a range of common mode voltages.

Differential input receiver circuit testing with a loopback circuit

A near-field communication (NFC) receiver includes first and second input terminals for receiving first and second input signals having a modulated signal portion and a carrier signal portion. The receiver includes a digital-to-analog converter (DAC), a mixer, a track-and-hold (T&H) circuit, an amplifier, and an analog-to-digital converter. The mixer has a first input coupled to receive the first and second input signals and a second input coupled to receive a low frequency current from the DAC. The mixer subtracts the carrier portion from the first and second input signals using the DAC current at a level determined using a DSP in a feedback loop to approximate the carrier. The T&H circuit has an input coupled to receive the combined current and an output to provide a series of output samples. The ADC is coupled to receive the amplified output signal and to provide a digital representation of the amplified output signal.

Carrier supression in a NFC receiver

Embodiments are provided for a method of operating a receiver system, the receiver system comprising one or more channels, the method comprising: monitoring a residual DC (direct current) offset in a present channel by sampling an output of an analog-to-digital converter (ADC) of the present channel; adjusting a DCO (direct current offset) correction signal that corresponds to the residual DC offset in response to an absolute value of the residual DC offset exceeding a programmable DCO threshold; and subtracting the DCO correction signal from an analog signal provided to the ADC to reduce the residual DC offset below the programmable DCO threshold.

Adaptive NFC receiver

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Saint Paul de Vence, France

Frederic Benoist