Abstract: An ECG signal acquisition system includes a first amplifier which has a non-inverting input adapted to be coupled to a first differential input, an inverting input adapted to be coupled to a second differential input, and an output. The system includes first and second biasing resistors coupled between the non-inverting and inverting inputs of the first amplifier. The system includes an average estimation circuit which has a first input coupled to the non-inverting input of the first amplifier and a second input coupled to the inverting input of the first amplifier. The system includes a driver amplifier which has an inverting input coupled to the output of the average estimation circuit, a non-inverting input coupled to receive a reference common-mode voltage, and an output. The system includes a low-pass filter coupled between the output of the driver amplifier and the biasing resistors.

Abstract: A bio-sensing device (and method) calibrates a time period used to make bio-physical measurements. The device initiates a light source sense phase followed by a first ambient sense phase and a second ambient sense phase. In the light source sense phase, the device is configured to receive a digital value indicative of current through a photodetector while the light source circuit is enabled and in each of the first and second ambient sense phases, the device is configured to receive digital values while the light source circuit is disabled. The device iteratively varies the time period between the phases until the digital value received during the first ambient sense phase is within a threshold of the digital value received during the second ambient sense phase. It then applies the same time separation between the light source sense phase and the ambient phase thereby equalizing the magnitude of the ambient light in the two phases.

Abstract: At least some embodiments are directed to a light detection system comprising a photodiode, a transimpedance amplifier (TIA) having a differential output and a differential input coupled across the photodiode, a first bias current source coupled to an anode of the photodiode, and a second bias current source coupled to a cathode of the photodiode. The system also comprises a dynamic control logic coupled to the first and second bias current sources and configured to vary bias currents provided by the first and second bias current sources based on the differential output such that the photodiode is reverse-biased.

Abstract: At least some embodiments are directed to a light detection system comprising a photodiode, a transimpedance amplifier (TIA) having a differential output and a differential input coupled across the photodiode, a first bias current source coupled to an anode of the photodiode, and a second bias current source coupled to a cathode of the photodiode. The system also comprises a dynamic control logic coupled to the first and second bias current sources and configured to vary bias currents provided by the first and second bias current sources based on the differential output such that the photodiode is reverse-biased.

Abstract: A bio-sensing device (and method) calibrates a time period used to make bio-physical measurements. The device initiates a light source sense phase followed by a first ambient sense phase and a second ambient sense phase. In the light source sense phase, the device is configured to receive a digital value indicative of current through a photodetector while the light source circuit is enabled and in each of the first and second ambient sense phases, the device is configured to receive digital values while the light source circuit is disabled. The device iteratively varies the time period between the phases until the digital value received during the first ambient sense phase is within a threshold of the digital value received during the second ambient sense phase. It then applies the same time separation between the light source sense phase and the ambient phase thereby equalizing the magnitude of the ambient light in the two phases.