Photoplethysmography sensor and semiconductor device including the same

A semiconductor device comprising:

• a light source configured to output light during a first time section, and configured not to output the light during a second time section following the first time section;
• and
• a detector configured to receive light outputted from the light source and reflected from a blood vessel, and configured to generate a first output voltage corresponding to light received during the first and second time sections,
• wherein the detector includes:
• a photoelectric conversion element configured to generate electric charges corresponding to the received light;
• and
• a storage unit configured to store the generated electric charges and generate the first output voltage, and
• wherein an amount of electric charges in the storage unit increases corresponding to electric charges generated by the photoelectric conversion element during the first time section, and decreases corresponding to electric charges generated by the photoelectric conversion element during the second time section.

A semiconductor device comprising:

• a light source configured to output light according to a first control signal having a first period, and modulate and output the light according to a second control signal having a second period shorter than the first period;
• a photoelectric conversion element configured to receive light outputted from the light source and reflected from a blood vessel, and generate a current corresponding to the received light;
• a current-to-voltage converter configured to generate an output voltage corresponding to the current generated from the photoelectric conversion element;
• and
• a switch configured to perform a first connection between the photoelectric conversion element and the current-to-voltage converter in response to the second control signal of a first level, and perform a second connection different from the first connection between the photoelectric conversion element and the current-to-voltage converter in response to the second control signal of a second level different from the first level.