Abstract: The present disclosure provides methods of protecting ribonucleic acid (RNA) from degradation under certain conditions by contacting the RNA with an amino acid. The present disclosure also provides compositions comprising such amino acid(s) and RNA.

Abstract: A photoplethysmographic (PPG) device is disclosed. The PPG device can include one or more light emitters and one or more light sensors to generate the multiple light paths for measuring a PPG signal and perfusion indices of a user. The multiple light paths between each pair of light emitters and light detectors can include different separation distances to generate both an accurate PPG signal and a perfusion index value to accommodate a variety of users and usage conditions. In some examples, the multiple light paths can include the same separation distances for noise cancellation due to artifacts resulting from, for example, tilt and/or pull of the device, a user's hair, a user's skin pigmentation, and/or motion. The PPG device can further include one or more lenses and/or reflectors to increase the signal strength and/or and to obscure the optical components and associated wiring from being visible to a user's eye.

Abstract: A photoplethysmographic (PPG) device is disclosed. The PPG device can include one or more light emitters and one or more light sensors to generate the multiple light paths for measuring a PPG signal and perfusion indices of a user. The multiple light paths between each pair of light emitters and light detectors can include different separation distances to generate both an accurate PPG signal and a perfusion index value to accommodate a variety of users and usage conditions. In some examples, the multiple light paths can include the same separation distances for noise cancellation due to artifacts resulting from, for example, tilt and/or pull of the device, a user's hair, a user's skin pigmentation, and/or motion. The PPG device can further include one or more lenses and/or reflectors to increase the signal strength and/or and to obscure the optical components and associated wiring from being visible to a user's eye.

Abstract: A method comprises coupling a charge phase circuit and a battery phase circuit to a battery, in a charge mode, turning on a plurality of first switches and turning off a plurality of second switches to connect the charge phase circuit to the battery and in a battery mode, turning on the plurality of second switches and turning off the plurality of first switches to connect the battery phase circuit to the battery.

Abstract: A portable electronic device include one or more electrodes for calculating distances and rotational angles between the device and the user is disclosed. Based on the calculated distances and rotational angles, a physical activity of the user can be determined. Additionally, the calculated distances and rotational angles can be used for compensation of optical artifacts in one or more signals detected by the device. User movement or physical activity can introduce optical artifacts, which can lead to erroneous determination of the one or more characteristics. The calculated distances and rotational angles can be used to reduce or remove the optical artifacts, leading to a more accurate determination of the one or more characteristics of the user.

Abstract: A photoplethysmographic (PPG) device is disclosed. The PPG device can include one or more light emitters and one or more light sensors to generate the multiple light paths for measuring a PPG signal and perfusion indices of a user. The multiple light paths between each pair of light emitters and light detectors can include different separation distances to generate both an accurate PPG signal and a perfusion index value to accommodate a variety of users and usage conditions. In some examples, the multiple light paths can include the same separation distances for noise cancellation due to artifacts resulting from, for example, tilt and/or pull of the device, a user's hair, a user's skin pigmentation, and/or motion. The PPG device can further include one or more lenses and/or reflectors to increase the signal strength and/or and to obscure the optical components and associated wiring from being visible to a user's eye.

Abstract: A method comprises coupling a charge phase circuit and a battery phase circuit to a battery, in a charge mode, turning on a plurality of first switches and turning off a plurality of second switches to connect the charge phase circuit to the battery and in a battery mode, turning on the plurality of second switches and turning off the plurality of first switches to connect the battery phase circuit to the battery.

Abstract: A photoplethysmographic (PPG) device is disclosed. The PPG device can include one or more light emitters and one or more light sensors to generate the multiple light paths for measuring a PPG signal and perfusion indices of a user. The multiple light paths between each pair of light emitters and light detectors can include different separation distances to generate both an accurate PPG signal and a perfusion index value to accommodate a variety of users and usage conditions. In some examples, the multiple light paths can include the same separation distances for noise cancellation due to artifacts resulting from, for example, tilt and/or pull of the device, a user's hair, a user's skin pigmentation, and/or motion. The PPG device can further include one or more lenses and/or reflectors to increase the signal strength and/or and to obscure the optical components and associated wiring from being visible to a user's eye.

Abstract: A battery fuel gauge apparatus comprises a protection device coupled to a battery pack, a current mirror device, wherein a first terminal of the current mirror device is connected to a first terminal of the protection device through a first switch and a second terminal of the current mirror device is connected to a second terminal of the protection device through a second switch, a sensing device coupled to the current mirror device, a transistor coupled to the sensing device and an operational amplifier comprising a first input coupled to the protection device, a second input coupled to the current mirror device and an output coupled to the transistor.

Abstract: A regulator includes a controller, a driving unit, a digital-to-analog converter, and a comparator. The controller outputs a digital reference voltage and a control signal responsive to a comparison signal. The driving unit generates an output voltage at a first node responsive to the control signal. The digital-to-analog converter generates an analog reference voltage responsive to the digital reference voltage. The comparator generates the comparison signal based on the analog reference voltage and the output voltage.

Abstract: A comparator circuit includes a comparator, a first selection circuit, and a switched-capacitor circuit. The comparator has a first terminal, a second terminal, and an output terminal. The comparator is configured to generate an output signal at the output terminal based on a first signal on the first terminal and a second signal on the second terminal. The first selection circuit is coupled with the first terminal of the comparator and configured to selectively set a first input signal or a first calibration signal as the first signal in response to a control signal. The switched-capacitor circuit is coupled with the output terminal and the second terminal of the comparator. The switched-capacitor circuit is configured to adjust and output the second signal based on the output signal.

Abstract: A power converter includes a first stage voltage modulator configured to receive an input voltage and provide a modulated voltage. A second stage power converter is configured to receive the modulated voltage and vary a switching frequency of the second stage power converter in accordance with the modulated voltage to provide an output voltage.

Abstract: A power management circuit and method are described. In the method, whether a first voltage and/or a voltage source are present is determined. Based on a first result of the determination, the first voltage is converted to a second voltage. A boost converter is used to convert the second voltage to a third voltage. Alternatively, based on a second result of the determination, a buck converter is used to convert the third voltage to the second voltage.

Abstract: A DC to DC converter includes a switching circuit and a controller. The switching circuit includes an inductor coupled to first and second voltage supply nodes and to a plurality of output loads. The controller is configured to monitor a current through the inductor and to selectively couple the inductor to each of the plurality of output loads such that at least one of the following criteria is met: 1) an average current through the inductor is minimized for the particular output loads coupled to the switching circuit, or 2) minimize a number of times the switching circuit is switched during a charging period for the particular output loads coupled to the switching circuit.

Abstract: A portable electronic device include one or more electrodes for calculating distances and rotational angles between the device and the user is disclosed. Based on the calculated distances and rotational angles, a physical activity of the user can be determined. Additionally, the calculated distances and rotational angles can be used for compensation of optical artifacts in one or more signals detected by the device. User movement or physical activity can introduce optical artifacts, which can lead to erroneous determination of the one or more characteristics. The calculated distances and rotational angles can be used to reduce or remove the optical artifacts, leading to a more accurate determination of the one or more characteristics of the user.

Abstract: A circuit includes an analog-to-digital converter (ADC). The ADC is configured to receive an analog feedback signal and an analog input signal and generate a digital output. The circuit further includes a digital filter configured to filter the digital output and a noise shaper. The noise shaper is configured to truncate the filtered digital output and generate a noise shaper output, and to shape quantization noise generated during truncation. The circuit further includes a pulse width modulation digital-to-analog converter (PWM DAC) configured to process the truncated digital output of the noise shaper output and generate a PWM DAC output.

Abstract: A photoplethysmographic (PPG) device is disclosed. The PPG device can include one or more light emitters and one or more light sensors to generate the multiple light paths for measuring a PPG signal and perfusion indices of a user. The multiple light paths between each pair of light emitters and light detectors can include different separation distances to generate both an accurate PPG signal and a perfusion index value to accommodate a variety of users and usage conditions. In some examples, the multiple light paths can include the same separation distances for noise cancellation due to artifacts resulting from, for example, tilt and/or pull of the device, a user's hair, a user's skin pigmentation, and/or motion. The PPG device can further include one or more lenses and/or reflectors to increase the signal strength and/or and to obscure the optical components and associated wiring from being visible to a user's eye.

Abstract: An apparatus for controlling slew rate is coupled to two adjustable voltage rails. The output of the apparatus is coupled to the gate of a switching element. By employing two adjustable voltage rails, the slew rate of the switching element is proportional to the voltage difference between the first adjustable rail and the second adjustable rail. The slew rate control apparatus can be applied to a variety of switching elements including N channel Field Effect Transistors (NFETs), P channel Field Effect Transistors (PFETs), current mode logic circuits and level shifter circuits.

Abstract: A battery fuel gauge apparatus comprises a protection device coupled to a battery pack, a current mirror device, wherein a first terminal of the current mirror device is connected to a first terminal of the protection device through a first switch and a second terminal of the current mirror device is connected to a second terminal of the protection device through a second switch, a sensing device coupled to the current mirror device, a transistor coupled to the sensing device and an operational amplifier comprising a first input coupled to the protection device, a second input coupled to the current mirror device and an output coupled to the transistor.

Abstract: A circuit includes an analog-to-digital converter (ADC). The ADC is configured to receive an analog feedback signal and an analog input signal and generate a digital output. The circuit further includes a digital filter configured to filter the digital output and a noise shaper. The noise shaper is configured to truncate the filtered digital output and generate a noise shaper output, and to shape quantization noise generated during truncation. The circuit further includes a pulse width modulation digital-to-analog converter (PWM DAC) configured to process the truncated digital output of the noise shaper output and generate a PWM DAC output.