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Katholieke Universiteit Leuven

Katholieke Universiteit Leuven, Ku Leuven R&d

Katholieke Universiteit Leuven, K.u. Leuven Research & Development

Shuang Song

Nick Van Helleputte

Jiawei Xu

Roland Van Wegberg

Qiuyang Lin

Filip Tavernier

A light-to-digital converter () comprises a light-to-current converter (); a current integrator () with an integrator output () resettable to a baseline level; and a counter () with a digital output (), wherein the light-to-current converter () is switchably connectable as a positive integration input to the current integrator (), for, during a light-collecting phase (-), integrating a current from the light-to-current converter (), the integrator output () starting from the baseline value and ending at a value to be digitized; a reference current source () is switchably connectable as a negative integration input to the current integrator (), for, during a counting phase (-) subsequent to the light-collecting phase (-), integrating a reference current from the reference current source (), the integrator output () starting from the value to be digitized and ending at the baseline value, the time spent integrating the reference current corresponding to the value to be digitized; and the counter () is configured for measuring the time.

Light-to-digital converter

An analog-to-digital converter, ADC, circuitry, comprises: an integrator connected to a capacitor, the integrator being configured to switch between integrating an analog input signal for ramping an integrator output and integrating a reference input signal for returning integrator output towards a threshold; a comparator for comparing integrator output to the threshold; and a timer for determining a time duration during which the reference input signal is integrated, the time duration providing a digital representation of an analog input signal value; the ADC circuitry further comprising a feedforward noise shaping loop configured to store a quantization error signal based on digitizing a first sample, the comparator being configured to receive a feedforward noise shaping signal for changing the threshold for digitizing a later sample of the analog input signal following the first sample.

Analog-to-digital converter circuitry, an integrated circuit device, a photoplethysmogram detector, a wearable device and a method for analog-to-digital conversion

A device for read-out of a photoplethysmography (PPG) signal comprises: a photodiode, which is configured to detect a PPG signal, the photodiode comprising a first and a second terminal; and a read-out circuitry for reading out the PPG signal, wherein an input stage is connected to receive a first and a second input signal from the terminals and a DC bias voltage, and wherein the input stage is configured for current sensing to provide a fully differential amplification of the input signals to a first and a second current signal, and wherein an output stage is configured to receive the current signals, wherein the current signals comprise an AC and a DC component of the PPG signal, and wherein the output stage is configured to generate a differential output voltage through a gain component.

Device for read-out of a photoplethysmography signal and a wearable sensor

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Leuven, Belgium

Shuang Song