Microsoft Technology Licensing, LLC

Genesis Microchip Corporation

Lawrence Albert Prather

Barry Thompson

Stefan M Wurster

Dane Snow

Richard McCauley

Charles Walter Boecker

Jouya Jadidian

Abdullah Ahmed

Ram Chilukuri

Niranjan Achugundla Puttaswamy

Ramakrishna R Venuthurupalli

Sami Bizzan

Examples are provided that relate to determining a capacitance based on a charge accumulated on a sense capacitor electrode. One example provides a head-mounted device comprising a facial-tracking sensor, a controller, and a charge sensing circuit connected to the facial-tracking sensor. The facial-tracking sensor includes a sense capacitor electrode configured to be positioned proximate to a surface of a face and form a capacitance based upon a distance between the sense capacitor electrode and the surface of the face, and the controller configured to apply a reference voltage to the sense capacitor electrode. The charge sensing circuit is configured to determine the capacitance of the sense capacitor electrode by determining an amount of charge accumulated on the sense capacitor electrode resulting from the reference voltage.

Determining charge on a facial-tracking sensor

A time-of-flight image sensor including a readout circuit is provided. The readout circuit may include a pixel array including multiple pixels. The pixel array may be configured to produce a pixel signal for each of one or more pixels over a series of timesteps. The pixel signal may include an illuminated value and a reset value. The readout circuit may further include a plurality of gain selection comparators configured to receive the pixel signal and select an amplifier gain value. The readout circuit may further include analog correlated double sampling circuitry. The readout circuit may further include a programmable gain amplifier configured to generate an amplified pixel signal from the pixel signal, which may be amplified at the selected amplifier gain value. The readout circuit may further include a plurality of analog-to-digital converters. Each of the analog-to-digital converters may have a common ramp generated by a global ramp generator.

Time-of-flight sensor readout circuit

A voltage mode laser diode driver selectively turns on and off a laser diode. An output stage has an output node configured to be connected to one of the terminals of the laser diode. Depending upon implementation, an active swing controller drives the output stage in a manner that substantially prevents inductive kickback from causing the output node voltage to swinging above the voltage level at the voltage output of the power supply, or swing below ground. The output stage provides a discharge path around the laser diode to shunt current associated with the inductive kickback, and substantially eliminates ringing on the output node of the output stage while the laser diode is off. A power supply controller adjusts the voltage level of the voltage output of the power supply so that current through the laser diode when on and emitting light is substantially equal to a predetermined desired current.

Power efficient laser diode driver circuit and method

An apparatus and method for processing Hsync and Vsync signals in graphic controllers to avoid a false reading of pulses caused by glitches. The apparatus and method involve detecting when the synch signal crosses the threshold for the first time. When this occurs, the output of the detection circuit is held for the predetermined period of time, even if subsequent transitions across threshold occur during this period. After the predetermined period expires, the output is released and may assume the same state as the input sync signal at that time. In this manner, a misinterpretation of the resolution format caused by the reading of a 'false' pulse caused by a glitch on a sync signal can be avoided.

Apparatus and method for processing synch signals in graphic controllers

A programmable delay element is provided for delaying a digital input signal. The programmable delay element comprises a discharge capacitor adapted to be precharged to a predetermined voltage in response to a first transition of the digital input signal. A transistor switch of a first type is provided for precharging the discharge capacitor to a predetermined voltage. A discharge current source is connected via a sense node to the discharge capacitor for discharging the capacitor in response to a subsequent opposite transition of the digital input signal. A transistor switch of a second type is provided for connecting the discharge capacitor to the discharge current source and thereby discharging the discharge capacitor. A reference voltage source is provided for applying a reference voltage to a reference node. A comparator is provided having a first input connected to the sense node and a second input connected to the reference node, such that an output of the comparator generates a delayed version of the digital input signal such that the subsequent opposite transition is delayed by an amount equal to the time for the capacitor to discharge to a voltage equal to the reference voltage.

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Boulder Creek, CA, United States of America

Lawrence Albert Prather