Intersil Americas Inc.

Itaru Hiromi

David W Ritter

Steven G Herbst

Philip V Golden

Warren Craddock

Pradeep Bhardwaj

An optical proximity detector includes a driver, light detector, analog front-end and digital back end. The driver drives the light source to emit light. The light detector produces a light detection signal indicative of a magnitude and a phase of a portion of the emitted light that reflects off an object and is incident on the light detector. The analog front-end includes amplification circuitry, and one or more analog-to-digital converters (ADCs) that output a digital light detection signal, or digital in-phase and quadrature-phase signals indicative thereof. The digital back-end includes a distance calculator and a precision estimator. The distance calculator produces a digital distance value in dependence on the digital light detection signal, or the digital in-phase and quadrature-phase signals, output by the ADC(s) of the analog front-end. The precision estimator produces a precision value indicative of a precision of the digital distance value.

Precision estimation for optical proximity detectors

An optical proximity detector includes a driver, light detector, analog front-end, sensor(s) that sense correction factor(s) (e.g., temperature, supply voltage and/or forward voltage drop), and a digital back end. The driver drives the light source to emit light. The light detector produces a light detection signal indicative of a magnitude and a phase of a portion of the emitted light that reflects off an object and is incident on the light detector. The analog front-end receives the light detection signal and outputs a digital light detection signal, or digital in-phase and quadrature-phase signals, which are provided to the digital back-end. The digital back-end performs closed loop correction(s) for dynamic variation(s) in gain and/or phase caused by a portion of the analog front-end, uses polynomial equation(s) and sensed correction factor(s) to perform open loop correction(s) for dynamic variations in temperature, supply voltage and/or forward voltage drop, and outputs a distance value.

Open loop correction for optical proximity detectors

A system and method for identifying a position of a moving object, regardless of static objects present in the optical field of an active infrared (IR) proximity detector, is provided. Moreover, a modulated light emitting diode (LED) signal is captured and processed through I/Q demodulation. Specifically, the reflections received at an IR sensor are demodulated to generate in-phase (I) and quadrature phase (Q) signals and the derivative of I/Q signals is obtained to isolate motion. For example, an I/Q domain differentiator or a high pass filter is employed to calculate the derivative, which actively remove the effects of all forms of static interference. Further, the phase of the derivative I/Q signals is determined and is utilized to reconstruct the distance at which the motion occurred.

Distance sensing by IQ domain differentiation of time of flight (TOF) measurements

Described herein are optical proximity detectors, methods for use therewith, and systems including an optical proximity detector. Such optical proximity detectors include an analog front-end and a digital back-end. In certain embodiments, the digital back-end includes a dynamic gain and phase offset corrector, a cross-talk corrector, a phase and magnitude calculator, and a static phase offset corrector. The dynamic gain and phase offset corrector corrects for dynamic variations in gain and phase offset of the analog front-end due to changes in temperature and/or operating voltage levels. The crosstalk corrector corrects for electrical and/or optical crosstalk associated with the analog front-end. The phase and magnitude calculator calculates phase and magnitude values in dependence on the corrected versions of digital in-phase and quadrature-phase signals received from the analog front-end. The static phase offset corrector corrects for a static phase offset of the optical proximity detector.

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Sunnyvale, CA, United States of America

Itaru Hiromi