Canesta, Inc.

Cadence Design Systems, Inc.

Edoardo Charbon

Cyrus Soli Bamji

Ilhami Torunoglu

Shiraz Shivji

An approach is provided for detecting EM waves using a photodetector coupled to an amplifier stage. The amplifier stage uses capacitive feedback to reduce or cancel intrinsic capacitance of the photodetector. A variety of capacitance structures may be used to provide the capacitive feedback such as shielded capacitors and capacitor arrays. The amplifier stage may be either single-ended or fully differential, depending upon the requirements of a particular application. Noise cancellation circuitry may also be included to reduce noise and offset sources present in the amplifier stage. The approach is applicable to a variety of contexts and applications. Example applications include, without limitation, detection of both brightness and Time of Flight (TOF) in 3D sensing applications. The approach may also be used to detect EM wave intensity in 2D sensing systems and, in general, for any application requiring simultaneously high speed and high sensitivity EM detection.

Electromagnetic wave detection arrangement with capacitive feedback

A system and method for protecting circuit designs from unauthorized use involves techniques for watermarking by embedding a hidden, recognizable input/output signature or code into the circuit design. An internal sequential function, such as a finite state machine, within the circuit design is used to generate a predictable output sequence when a known input sequence is applied. The free input configurations in the internal sequential function of the circuit design are identified and modified to generate the desired output sequence when the known input sequence is applied. A path among the free input configurations is selected, with output values in the desired output sequence being assigned the various state transitions. If there are not enough free input configurations to meet specified watermarking robustness criteria, then additional free input configurations may be added by, for example, adding one or more inputs, outputs or states to the finite state machine. Various techniques for arriving at an optimal path so as to minimize overhead caused by the addition of the watermark are also disclosed.

Watermarking based protection of virtual component blocks

High dynamic range brightness information is acquired by inputting detection current to a high (adjustable) gain resettable integrator whose output V(t) is compared to a Vth threshold by a comparator whose output is counted by a reset counter as V(t)&gE;Vth. When a desired count is attained, data acquisition ends, the counter is read, and the entire circuit is reset. A TOF data acquisition circuit includes first and second sequences of series-coupled delay units, and a like number of latch units coupled between respective delay units. A phase discriminator compares output from each chain and feedback a signal to one of the chains and to a comparator and can equalize delay through each chain. A control voltage is coupled to the remaining chain to affect through-propagation delay time. The latch units can capture the precise time when V(t)&gE;Vth. Successive measurement approximation can enhance TOF resolution.

Method and system to enhance dynamic range conversion useable with CMOS three-dimensional imaging

A three-dimensional time-of-flight (TOF) system includes a low power optical emitter whose idealized output S &equals;cos(&ohgr;&middot;t) is reflected by a target distance z away as S &equals;A&middot;cos(&ohgr;&middot;t&plus;&PHgr;), for detection by a two-dimensional array of pixel detectors and associated narrow bandwidth detector electronics and processing circuitry preferably fabricated on a common CMOS IC. Phase shift &PHgr; is proportional to TOF or z, z&equals;&PHgr;&middot;C/2&middot;&ohgr;&equals;&PHgr;&middot;C/&lcub;2&middot;(2&middot;&pgr;&middot;f)&rcub;, and A is brightness. &PHgr;, z, and A are determined by homodyne-mixing S with an internally generated phase-delayed version of S , whose phase is dynamically forced to match the phase of S by closed-loop feedback. Idealized mixer output per each pixel detector is 0.5&middot;A&middot;&lcub;cos(2&ohgr;&middot;t&plus;&PHgr;)&plus;cos(&PHgr;)&rcub;. On-chip circuitry can use TOE data to simultaneously measure distance, object point velocity, object contours, including user interface with virtual input devices.

CMOS-compatible three-dimensional image sensing using reduced peak energy

A preferably CMOS-implementable system measures distance and/or brightness by illuminating a target with emitted optical energy having a modulated periodic waveform whose high frequency component may be idealized as S &equals;cos(&ohgr;&middot;t). A fraction of the emitted optical energy is reflected by a target and detected with at least one in a plurality of semiconductor photodetectors. Photodetector quantum efficiency is modulated to process detected signals to yield data proportional to the distance z separating the target and photodetector. Detection includes measuring phase change between the emitted optical energy and the reflected fraction thereof. Quantum efficiency can be modulated with fixed or variable phase methods and may be enhanced using enhanced photocharge collection, differential modulation, and spatial and temporal multiplexing. System power requirements may be reduced with inductors that resonate with photodetector capacitance at the operating frequency. The system includes on-chip photodetectors, associated electronics, and processing.

Systems for CMOS-compatible three-dimensional image sensing using quantum efficiency modulation

A three-dimensional imaging system is fabricated on a single IC. The system includes a two-dimensional array of pixel light sensing detectors and dedicated electronics and associated processing circuitry, all preferably fabricated on a single IC using CMOS fabrication techniques. The system includes a detector array comprising a plurality of pixel photodiodes and photodiode circuits, wherein each pixel photodiode acquires delay time data and pulse brightness data simultaneously. The system emits an energy pulse at time t0 and a fraction of the energy is returned to the array by a target object. Photodiodes in the array output a brightness signal B(t) that is integrated. An elapsed time ET from t0 to when said B(t) attains a predetermined threshold value is determined, where the slope of B(t) is B/PW, where B is B(t) after integrating over a time equal to the emitted pulse width PW. Time-of-flight TOF representing time from t0 to when a photodiode begins to detect energy is determined, where TOF&equals;ET&minus;IT, where IT is proportional to PW/B. A system processor determines distance from the system to the target object, from TOF and the velocity of light, and can translate TOF into commands to control electronic devices.

Noise reduction techniques suitable for three-dimensional information acquirable with CMOS-compatible image sensor ICS

A preferably CMOS-implementable method measures distance and/or brightness by illuminating a target with emitted optical energy having a modulated periodic waveform whose high frequency component may be idealized as S &equals;cos(&ohgr;&middot;t). A fraction of the emitted optical energy is reflected by a target and detected with at least one in a plurality of semiconductor photodetectors. Photodetector quantum efficiency is modulated to process detected signals to yield data proportional to the distance z separating the target and photodetector. Detection includes measuring phase change between the emitted optical energy and the reflected fraction thereof. Quantum efficiency can be modulated with fixed or variable phase methods and may be enhanced using enhanced photocharge collection, differential modulation, and spatial and temporal multiplexing. System power requirements may be reduced with inductors that resonate with photodetector capacitance at the operating frequency. The method can be implemented with on-chip photodetectors, associated electronics, and processing.

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Berkeley, CA, United States of America

Edoardo Charbon