Abstract: A pixelated monolithic photoplethysmographic (PPG) sensor with a spiking neural network structure and a driving method thereof are disclosed. The pixelated monolithic photoplethysmographic (PPG) sensor according to an exemplary embodiment of the present disclosure includes a plurality of input neurons which generates spike signals and is disposed in at least one of a row direction and a column direction, a plurality of output neurons which adds the spike signals applied from the plurality of input neurons based on the column direction or the row direction and generates an output spike signal when the added result is equal to or higher than a predetermined reference value, and a synchronizer which converts each of the output spike signals into a digital signal.

Abstract: A light-to-digital converter of the present invention includes: a plurality of light-to-digital conversion units each creating a first clock signal by performing delta-sigma conversion on a photodiode voltage created from an unbiased photodiode, and outputting a unit output signal obtained by synchronizing the first clock signal with a second clock signal that is a reference clock signal; and an adder outputting a digital output signal by adding up the unit output signals of the plurality of light-to-digital conversion units.

Abstract: A light-to-digital converter of the present invention includes: a plurality of light-to-digital conversion units each creating a first clock signal by performing delta-sigma conversion on a photodiode voltage created from an unbiased photodiode, and outputting a unit output signal obtained by synchronizing the first clock signal with a second clock signal that is a reference clock signal; and an adder outputting a digital output signal by adding up the unit output signals of the plurality of light-to-digital conversion units.

Abstract: The present invention relates to a time digital converter, and more particularly, to a noise-shaping time to digital converter (TDC) that has a 1-bit output and uses a delta-sigma modulation method. The noise-shaping time to digital converter (TDC) that has the 1-bit output and uses the delta-sigma modulation method in accordance with the present invention eliminates the need for a large number of D flip-flops or counters and a plurality of delay units connected in series to one another because the time to digital converter is fabricated such that a delay element has a resolution of the effective delay time in a semiconductor process, unlike the conventional time to digital converter. Therefore, the time to digital converter of the present invention has an advantage in that an extremely high resolution and high linearity can be achieved with an efficient circuit configuration and low power consumption.

Abstract: The present invention relates to a time digital converter, and more particularly, to a noise-shaping time to digital converter (TDC) that has a 1-bit output and uses a delta-sigma modulation method. The noise-shaping time to digital converter (TDC) that has the 1-bit output and uses the delta-sigma modulation method in accordance with the present invention eliminates the need for a large number of D flip-flops or counters and a plurality of delay units connected in series to one another because the time to digital converter is fabricated such that a delay element has a resolution of the effective delay time in a semiconductor process, unlike the conventional time to digital converter. Therefore, the time to digital converter of the present invention has an advantage in that an extremely high resolution and high linearity can be achieved with an efficient circuit configuration and low power consumption.