Abstract: A method for operating an optical sensing device having a light source and a photodetector device with at least one photosensitive element. A surface portion is illuminated with radiation by the light source and the radiation reflected from the illuminated surface portion is detected with a photosensitive element. While said surface portion is being illuminated, an output signal of the photosensitive element over time is integrated, the output signal integration level is compared with a first integration reference level during integration; the integration step is interrupted if the output signal integration level has reached the first integration reference level, or the comparison step is repeated until a first integration period has elapsed if the output signal integration level has not reached the first integration reference level.

Abstract: A method for detecting lift from a surface portion of an optical pointing device comprising a coherent light source, a photodetector device including an array of pixels, and means for extracting motion features including comparators with an adjustable offset value, the method comprising the steps of: (i) illuminating said surface portion with radiation by means of said coherent light source; (ii) detecting radiation patterns reflected from the illuminated surface portion by means of said photodetector device; (iii) comparing light intensity between neighbouring pixels in said detected radiation patterns; (iv) extracting motion features as a function of the result of said comparison; (v) counting the total number of motion features extracted; (vi) increasing, respectively decreasing, said comparator offset value when said total number of motion features increases, respectively decreases; wherein the method further comprises the steps of: (vii) comparing said comparator offset value with an offset threshold; (v

Abstract: A method for measuring relative motion between an illuminated portion of a surface and an optical sensing device comprising a coherent light source and a photodetector device comprising an array of pixels and comparators for extracting motion features, said method comprising the steps of: a) illuminating by means of said coherent light source said surface portion at a determined flash rate; b) detecting by means of said array of pixels a speckled light intensity pattern of said illuminated portion of the surface for each flash; c) extracting edge direction data of two different types from said detected speckled light intensity patterns by comparing light intensity between pixels; d) determining a measurement of the relative motion between said optical sensing device and said illuminated portion of the surface based on extracted edge direction data; wherein the extracting edge direction data step comprises a preliminary step consisting of introducing a selecting factor which promotes detection of one ty

Abstract: There is described a method as well as a device for motion detect ion in an optical sensing device, such as an optical mouse. A photodetector array comprising a plurality of pixels is used to detect successive light intensity patterns of an illuminated portion of a surface with respect to which a measurement of relative motion is to be determined. Light intensity between neighbouring pixels is compared in order to determine edge direction data descriptive of light intensity differences between the pixels, such data including (i) a first edge condition, or positive edge, defined as a condition wherein light intensity of a first pixel is less than light intensity of a second pixel, and (ii) a second edge condition, or negative edge, defined as a condition wherein light intensity of the first pixel is greater than light intensity of the second pixel.

Abstract: There is described an integrating circuit for converting light energy produced by a photodetector into a voltage signal, this integrating circuit comprising an amplifier having an input coupled to a terminal of the photodetector and an output for outputting the voltage signal, and an integration capacitor having a first electrode connected to the amplifier input and a second electrode connected to the amplifier output. The first electrode of the capacitor is formed by the terminal of the photodetector connected to the amplifier input and the second electrode is formed by a layer of conductive material deposited on top of the photodetector and separated from this photodetector by a layer of insulating material, these layers of conductive material and of insulating material being transparent or nearly transparent at least for a given range of wavelengths of light. There is also described a method of forming the integration capacitor as well as a photodetector including the integration capacitor.

Abstract: There is described an integrating circuit (20) for use with a photodetector (10) and an optical sensor (1) including such an integrating circuit. The integrating circuit comprises an operational amplifier (30) having a non-inverting input (32) connected to a non-zero bias voltage (VPD-BIAS), an inverting input (31) coupled to the photodetector (10), and at least one output (33). This integrating circuit further includes an integrating voltage storage device (25) having a first terminal coupled to the operational amplifier output and a second terminal coupled to the operational amplifier inverting input, and switching circuitry for controlling timing of the integrating circuit and switching the integrating circuit between a reset phase and an integration phase.

Abstract: There is described a method, a sensing device as well as an optical pointing device including a sensing device for comparing light intensity between pixels. Light intensity between pairs of pixels of a photodetector array is compared as follows. First and second output signals generated by the photosensitive elements of a first and a second pixel of each pair are integrated over time to respectively provide first and second integrated signals. Integration of the first output signal is interrupted at the end of a first time period and the resulting first integrated signal is stored. Integration of the second output signal is continued until the end of a second time period and the resulting second integrated signal is compared to the stored first integrated signal to provide an output signal representative of an edge condition between the first and second pixel.

Abstract: An amplifier circuit (10) having a rotating input stage has a switching network (12) connected to an input (14). A number of parallel transconductance gain stages (16) are connected to the switching network (12). An auto-zeroing circuit (18) is connected to the switching network (12). A second transconductance gain stage (20) is connected to the parallel transconductance gain stages (16).

Abstract: There is described an integrating circuit (20) for use with a photodetector (10) and an optical sensor (1) including such an integrating circuit. The integrating circuit comprises an operational amplifier (30) having a non-inverting input (32) connected to a non-zero bias voltage (VPD-BIAS), an inverting input (31) coupled to the photodetector (10), and at least one output (33). This integrating circuit further includes an integrating voltage storage device (25) having a first terminal coupled to the operational amplifier output and a second terminal coupled to the operational amplifier inverting input, and switching circuitry for controlling timing of the integrating circuit and switching the integrating circuit between a reset phase and an integration phase.

Abstract: There is described a method, a sensing device as well as an optical pointing device including a sensing device for comparing light intensity between pixels. Light intensity between pairs of pixels of a photodetector array is compared as follows. First and second output signals generated by the photosensitive elements of a first and a second pixel of each pair are integrated over time to respectively provide first and second integrated signals. Integration of the first output signal is interrupted at the end of a first time period and the resulting first integrated signal is stored. Integration of the second output signal is continued until the end of a second time period and the resulting second integrated signal is compared to the stored first integrated signal to provide an output signal representative of an edge condition between the first and second pixel.

Abstract: A low-corner frequency high pass filter circuit (10) includes an operational amplifier (12). The operational amplifier (12) has an inverting input (14) and a non-inverting input (24). A series capacitor (26) has a first end connected to the non-inverting input (24) of the operational amplifier (12). A second end of the series capacitor (26) is connected to an input signal (28). A low gain amplifier (30) has an input connected to an output (22) of the operational amplifier (12) and has an output (32) connected to the non-inverting input (24) of the operational amplifier (12). The low gain amplifier (30) performs the function of large value resistor.

Abstract: An injection current test circuit for an amplifier (24) includes a test current input pad (16). One (14) of a plurality of current mirrors (12) is connected to the test current input pad (16). A switch (20) is connected to a second (18) of the plurality of current mirrors (12) and connected to the amplifier (24). A test current output pad (22) is connected to the switch (20).

Abstract: A low-corner frequency high pass filter circuit (10) includes an operational amplifier (12). The operational amplifier (12) has an inverting input (14) and a non-inverting input (24). A series capacitor (26) has a first end connected to the non-inverting input (24) of the operational amplifier (12). A second end of the series capacitor (26) is connected to an input signal (28). A low gain amplifier (30) has an input connected to an output (22) of the operational amplifier (12) and has an output (32) connected to the non-inverting input (24) of the operational amplifier (12). The low gain amplifier (30) performs the function of large value resistor.

Abstract: A parasitically compensated resistor (50) for integrated circuits includes a substrate (52). A polysilicon resistor (54) is formed in the substrate (52). The polysilicon resistor (54) has a first end connected to a first lead (56) and a second end connected to a second lead (58). A conductive layer (62) is capacitively connected to the polysilicon resistor (54).

Abstract: An amplifier circuit (10) having a rotating input stage has a switching network (12) connected to an input (14). A number of parallel transconductance gain stages (16) are connected to the switching network (12). An auto-zeroing circuit (18) is connected to the switching network (12). A second transconductance gain stage (20) is connected to the parallel transconductance gain stages (16).

Abstract: An amplifier circuit (20) for a photodetector includes a transconductance variable gain stage (32). The transconductance variable gain stage (32) has an input (34) capable of connecting to the photodetector and an output (40). A transconductance gain stage (44) has an input (42) connected to the output (40) of the transconductance variable gain stage (32). A feedback resistor (46) is connected between an output (48) of the transconductance gain stage (44) and the input (42) of the transconductance gain stage (44).

Abstract: An amplifier circuit (20) for a photodetector includes a transconductance variable gain stage (32). The transconductance variable gain stage (32) has an input (34) capable of connecting to the photodetector and an output (40). A transconductance gain stage (44) has an input (42) connected to the output (40) of the transconductance variable gain stage (32). A feedback resistor (46) is connected between an output (48) of the transconductance gain stage (44) and the input (42) of the transconductance gain stage (44).