TW201142568A - Direct current (DC) correction circuit for a time of flight (TOF) photodiode front end - Google Patents

Abstract

A system and method that compensates for the effects of ambient light in a time of flight (TOF) sensor front end is provided. Moreover, a direct current (DC) correction loop is utilized at the front end, which removes a DC component from a current generated by the TOF sensor and accordingly prevents saturating the front end. The DC correction loop attenuates the DC component without adding significant thermal noise at a modulation frequency and provides a corrected signal to the front end circuitry. The corrected signal is processed and utilized to detect a position of an object within the optical field of the sensor.

Description

201142568 VI. Description of the Invention: [Technical Field] The present invention relates to a time-of-flight photodiode preamplifier, and more particularly to a DC correction circuit for use in a flight time photodiode preamplifier. CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to US Provisional Patent Application Serial No. 61/298,895, filed Jan. The ARCHITECTURE FOR A REFLECTION BASED LONG RANGE PROXIMITY AND MOTION DETECTOR HAVING AN INTEGRATED AMBIENT LIGHT SENSOR) is incorporated herein by reference. Further, the present application is also related to the following U.S. Patent Application: copending U.S. Patent Application Serial No. 12/979,726, filed on Dec. 28, 2010. ), the case titled "DISTANCE SENSING BY IQ DOMAIN DIFFERENTIATION OF TIME OF FLIGHT (TOF) MEASUREMENTS"; _____月__曰提申Co-pending U.S. Patent Application Serial No. __________ (legal file number SE-2785-AN/INTEP105USC), titled "Photodiode Front Stage with Improved Power Supply Rejection Ratio (PHOTODIODE FRONT END) WITH IMPROVED POWER SUPPLY REJECTION RATIO(PSRR))"; ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ /INTEP105USD), the case titled "AUTOMATIC ZERO CALIBRATION TECHNIQUE FOR TIME OF FLIGHT (TOF) TRANSCEIVERS"; ____ __月__日提申U.S. Patents pending in the same case, please Serial No. __________ (legal file number

SE-2877-AN/INTEP105USE), the title of the case is "SERIAL-CHAINING PROXIMITY SENSORS FOR GESTURE RECOGNITION"; and ____ years __月__曰提The copending U.S. Patent Application Serial No. __________ (Legal No. SE-2878-AN/INTEP105USF), titled "GESTURE RECOGNITION WITH PRINCIPAL COMPONENT ANALYSIS" . Each of the previous applications is incorporated by reference in its entirety. [Prior Art] 201142568 [Invention] There is an emerging integrated device that allows electronic products to sense their environment. These devices include a wide variety of devices, such as accelerometers, monolithic gyroscopes, light sensors, and imagers. Ming Ball said that light sensors are the simplest and cheapest ones, which allows them to be incorporated into many consumer products, for example, nightlights, cameras, cellular phones, laptops. Computer,...etc. In general, light sensors can be used in a wide variety of applications related to proximity sensing, for example, but not limited to: detecting the presence of a user and/or detecting the user to The distance of the product for the purpose of controlling power, display, or other interface options. The infrared (InfraRed' IR) proximity detector uses ir light to sense the objects in the sensing area of the IR sensor. Furthermore, the IR light is emitted by the _IR Lighting Emitting Diode (LED) emitter, which deflects off at objects in the surrounding area and is reflected by a detector. Furthermore, the detector may be a diode (for example, a PIN diode), and/or any other type of device that converts IR light into an electrical signal. The sensed signal is analyzed to determine if an object is present in the sensing area. Some conventional systems emit an IR light pulse and detect if the pulse returns to the PIN diode. However, observing this ignorance is very confusing because of the existing IR light, for example, 201142568 said, ambient light, sunlight, _. Moreover, such conventional systems are also incapable of distinguishing between non-sense reflections from static objects (eg, 'chairs, tables, soda cans, etc.) and from the objects (eg, humans, animals, etc.) Reflection. Thus, in order to compensate for the existing light, the conventional system measures the data twice: once when the IR emitter is turned on and emits the -ir pulse; and once when the emitter is turned off. Furthermore, the IR responses in both cases are measured and subtracted. However, implementing such calculations is a cumbersome and time consuming process. & In addition, the range of such conventional detectors is only about 10 to 30 cm (cm, i隹 'half knives 1) progress, for a larger range (for example, Overcoming the effects of ambient light in the range of 20 to 30 cm, the xenon LED must also emit a large amount of power. The systems and methods disclosed herein provide a novel signal processing technique for active long range distance sensors that prevents DC (Direct Cunrent, DC) saturation of the front stage without causing significant noise (example: Said, noise spectrum density). For example, the distance sensor disclosed herein may range from 1 to 2 meters. In one of the views, the light emitted by an IR is modulated at the frequency, for example, 1 MHz to 50 MHz. Then, the received ir response, for example, is demodulated by using a quadrature amplitude demodulator (I/Q demodulation) and processed to confirm an object and the sensor. The distance between them. It will be understood that although the specification of the present invention is described herein with reference to IR light; however, the systems and methods disclosed herein can utilize most of any wavelength. For example, the system and/or method steps of the present invention can be used in sonic proximity applications and/or ultrasonic range finding applications. Further, although the interpretation and description of this book 7 201142568 is the light / _, to the alpha state (for example, the light diode); however, the system can be understood, and ',,, and also shame Convert a physical input to most of the electrical requirements of the electrical §fl number. This article will refer to the schema to illustrate the main content of this issue + praise, in which all the same component symbols in the schema are to be used for 矣 _ now you are used to distinguish components. For the purposes of explanation, many specific details are set forth in the description which follows. However, it can be implemented in the main inner valley of I Feng Ming, even if there is no clear details. In other instances, well-known structures and devices are shown in the form of block diagrams to help illustrate the invention. Of course, those skilled in the art will appreciate that modifications may be made to this configuration without departing from the scope or spirit of the subject matter of the invention as claimed herein. ... Again, the term "exemplary" as used in this document means "as an example, an instance" or an explanation. The (4) views or designs described herein as "exemplary" are not necessarily considered to be preferred views or designs or superior to other ideas or designs. To be precise, "the use of exemplary words is intended to present various concepts in a concrete form. The term "or" used in this application is intended to mean an inclusive "or" rather than a repulsive one. "." That is, unless explicitly mentioned, or the meaning of the text is very clear; otherwise, "X uses A or B" hopes to mean any essentially inclusive arrangement. That is, if X uses Α; χ uses B; or χ uses 8 and 6; then, in any of the above cases, it conforms to "X use Α or Β". In addition, unless expressly stated to the 'or the singular form, the singular form is used in the context of the application and the scope of the accompanying claims, the term "one" 201142568 should be considered to mean "one or Multiple". Furthermore, the term "coupled" as used herein refers to a direct or indirect electrical or mechanical coupling. Further, unless there is a special distinction between the terms "sensearea", "visionfield", "optical field" and the similar terms in the text; otherwise, Words and similar terms can be used interchangeably in this application. Furthermore, the term "environment" as used herein may refer to light having most of any reasonable spectrum, for example, but not limited to: white hot light, fluorescent 'sunlight', any black body temperature, and / Or a combination of them. Furthermore, the term "ambient light" as used herein may encompass most of any light from a constant source of light. [Embodiment] The figure is shown in accordance with an aspect of the present disclosure. The dc saturation example system 100 is reduced in the front stage of a long range proximity detector. In general, System 1 can be used in most of any light sensing applications and/or optical proximity applications. For example, a laptop or a personal computer may be powered on by using the system 1 when the debt is measured to a usage (for example, '1 from sleep, standby, etc.) or, § When the operator is too close to a machine, the machine will use the system 100 to alert the operator if the user is in danger. In another example, the hive = phone or personal digital assistant (p_nal Digital Assis, PDA) may turn off the display by using the system 1GG when detecting that the phone/pDA is being held at the user's ear. (to save battery life). 201142568 In general, System 100 uses the TIME OF FLIGHT 'TOF measurement, which relies on the limited speed of light. This limited speed causes a delay between the emission of an electromagnetic wave and its reflection from an object. 'This delay will be proportional to the distance of the object. In System 1 该, the distance may be measured with a phase delay of the IR LED signal that is modulated (for example, at 5 MHz). Furthermore, for proximity sensing based on IR signal detection, system 100 utilizes an IR LED 102 and an ir sensor 104. For example, the system 1 may utilize a high frequency (e.g., 5 MHz) modulated LED 102 and a tuned pin detector 104' to optimize the detection range. In general, an LED driver 106 may be used to provide an input signal (e.g., a frequency modulated signal) to the LED 102. In general, in synchronous detection (for example, by the sensor pre-stage circuitry 11 8), a local oscillator (not shown) that is synchronized to the LED driver may be employed. For example, the IR LED 102 will have a typical spike wavelength that matches the proximity sensor spectrum; a narrow viewing angle with higher radiation intensity that can help gather energy that is well suited for proximity sensing. It can be understood that most of the IR LEDs (or arrays) can be applied based on the following coefficients, for example, but not limited to: viewing angle, mechanical height, coverage, radiant intensity, current Consumption, ..., etc. Further, the ir LED 102 can transmit the modulated IR signal 108 to the sensing object 丨10; and the IR sensor 104 can receive a portion of the transmitted signal 1 i 2 from the subtracted object 11 The surface of the crucible is reflected back. The object 11 may be a majority of any entity of interest, such as 'but not limited to: human body, from 10 201142568 kinetic elements, devices, articles, animals, ... and the like. In general, the size of the reflection H2 will depend on the size of the object 110, the color of the object 1 10, and the distance separating the object 1 10 from the IR sensor 1〇4. For example, a white shirt may produce a higher reflection than a black shirt. In addition to the reflections 112 from the object 110, the sensor 104 may also receive various other signals 114, such as, but not limited to, electrical crosstalk, optical crosstalk, and/or environmental backscattering ( Environmental backscatter). Each of these signals represents interference caused by speculation of the object of interest. The electrical crosstalk and optical crosstalk among the interferers may be approximately constant during the life of the device and can be corrected at the manufacturing or development stage of the application. The ambient backscatter 114 may be from various sources in the range of light received from the sensor 1〇4 and may include most of the signals detected by the object 10 that are not of interest. For example, objects such as table surfaces, couches, television displays, soda cans, etc. are not practical targets, but are detected as an important component of the signals received at the sensor 104. . In one embodiment, the constant light sources (for example, fluorescent, electric light, sunlight, etc.) will collectively become ambient light incident on the sensor 104.

The signal generated by the benefit. For example, most of the circuits 201142568 that can be used by the latter stage may contain one or more amplifiers, one or more Analog-to-Digital Converters (ADCs), and / Or a signal processor. In one of the views, 'system 100 will use Dc correction circuit 116', which will adaptively adjust the thermal noise of different ambient light conditions and eliminate the DC saturation current introduced by the % i-light. System 1 is connected to noise/popular noise (for example, thermal noise. In one example, the DC correction circuit 丨16 may mimic a correction error signal generated by ambient light. The inductors are explained in more detail below with reference to Figures 2, 3, and 4. It will be appreciated that the mechanical design of system 100 may include different component selections, different component placement methods, different dimensions, different glasses. Cover features, different led selections, different isolation techniques between sensor 104 and LED 1〇2, etc., for optimal proximity sensing. Furthermore, LED 102 may be the majority of any source. For example, but not limited to. LED, organic LED (〇rganic LED, OLED), body-emitting LED, surface-emitting LED, vertical cavity surface emitting laser (VCSEL), ultra-cold light emission Super luminescent Light Emitting Diode (SLED), laser diode diode, or the like. It is understood that the light source can generate IR light or have most of the other wavelengths. It is also understood that the sensor may also contain most of the light detecting requirements that can be used to generate a current or voltage that is indicative of the magnitude of the detected light, such as However, it is not limited to · photoresistors, photovoltaic cells, photodiodes, optoelectronic crystals, charge coupled devices (CCD), or the like. 12 201142568 Into - step, you can also It will be appreciated that the LED driver 1 〇 6 and the pre-stage circuitry 118 may contain most of any of the electrical circuit(s), which may include components and circuitry requirements having any convenient values to implement the practice of the present invention. In addition, LED driver 1, DC correction circuit 116, and pre-stage circuitry 118 may also be implemented on one or more integrated circuit (IC) wafers and possibly It is incorporated in the same or different package(s). In general, various IR bands (for example, near-band, medium-wave IR, and long-wave IR bands) can be utilized in the imaging system. There may be unique LEDs and sensors for each frequency band. Typically, some visible light detectors will operate in the near IR band and may contain detectors integrated into the system ic. In addition, it is also understandable that the system is not limited to the use of IR forces, and the LED/sensor/detector can also use signals with most of any wavelength. Referring now to Figure 2, there is shown an exemplary system in accordance with one aspect of the present specification including an IC 2 〇 2 that corrects an error signal generated by a sensor due to ambient light during distance sensing. . Furthermore, IC 2〇2 can also be considered as a primary distance monitoring system and/or as a component for correcting legacy systems. Specifically, the IC 202 includes a Dc correction loop ιι6, an amplifier 204, and a distance determining circuit 〇6 which confirms the distance between an object and the PIN diode. It will be appreciated that the correction loop 116 may include, for example, the functionality fully described herein for the system. Further, although a single IC (202) is illustrated in Fig. 2; however, the system can be implemented using a plurality of ICs or devices. 13 201142568 The active IR proximity detector disclosed in this paper uses a 1R LED emitter to emit IR light, which is reflected away from objects in the sensing area, and reflections from such objects are detected. A device (for example, a PIN diode) is sensed. In general, ambient light is also incident on the detector together with the reflected light. In particular, the ambient light and/or other error signals (e.g., leakage current from the photodiode) provide a DC value in the current generated by the detector. For example, ambient light may contain most of any low frequency light, including: sunlight, artificial light (for example, intended to illuminate a room or an area), and/or from a movement that may not be of interest. The shadow/light of the object. In another example, ambient light may also include higher frequency light from an artificial light source, such as 100 Hz or 120 Hz light with various higher resonances emitted by light directly driven by the power line. The higher frequency of the light emitted by the fluorescent illumination driven by the small transformer circuit in the frequency range of 1 kHz and the resonant frequency. Traditionally, the gain switching system is used. (where the system gain is adaptive) I to correct the DC error caused by ambient light in response to ambient light. Alternatively, a switched capacitor cancellation technique or a TransImpedance Amplifier (TIA) II C L positive with a bypass circuit may be used. However, some complex systems may introduce significant noise (for example, noise spectral density) in the detector month. Conversely, the Shen correction circuit 116 uses a simple, cost-effective, and low-noise circuit that maintains a constant gain at the front of the detector, thus simplifying the design. In the middle view, the DC correction loop 116 can be adapted to the full range of DC current at the modulation frequency 9 9201142568 (for example, 5 MHz) (for example, due to ambient light and/or most of any error signals) ), the result of the unfavorable is only a small amount of noise. Furthermore, the 帛DC correction circuit i 16 also provides a circuit for transmitting high frequency optical signals (for example, reflected from an object) to the amplifier 204 or to a wave filter (not shown), which simultaneously reduces/decreases A lower frequency signal produced by ambient light incident on the detector. In one example, the DC correction loop i 16 mimics an inductor that removes the DC component of the diode current and prevents saturation of the front stage of the proximity detection circuit. Specifically, the DC correction loop 116 utilizes a architecture that achieves DC correction, but does not add thermal §fl (for example, 'low noise spectral density') at the modulation frequency. An example circuit for the DC correction loop will be described in detail in Figures 3 and 40. The Dc correction loop can contain two amplifiers, for example, transconductance amplifiers (gmi and gm2). In addition, a 'capacitor resistor pair (Cf, Rf) can be used to attenuate the noise transfer function of the first transconductance amplifier (gm!), and the bias of the second transconductance amplifier (gm2) is automatic and Dynamically adjusted to reduce noise. The high frequency signal from the DC correction loop is then transmitted to one or more preamplifiers 204. The amplified signal is provided to a distance decision circuit 206 for proximity/motion detection. In one example, the distance decision circuit 206 may include a demodulator, for example, a demodulation circuit for demodulating the amplified signal; and a method for confirming the solution. The circuit that modulates the phase of the signal to the purpose of TOF measurement. 3 is an exemplary circuit diagram 300 for compensating for DC current generated by an optical sensor, in accordance with an aspect of the present invention. In one of the examples 15 201142568, the circuit 300 can operate in the presence of ambient light (for example, up to lOOklux), and the transport 300 is not at the modulation frequency / " In addition to this, the circuit adds significant noise to the 5th level (for example, the noise power spectral density). Furthermore, the "obvious noise" and / or "substantial noise" used in this article. The number of spectral power spectral densities of the known noise is above the pre-defined threshold, and the error is introduced in the call. The boundary value will be in the proximity/transport (4). The photodiode 302 will respond to the incident. The light on it produces a current Iambient+Signal and is supplied to the capacitor Cd 3 〇. Incident above the photodiode %2 = the light contains light reflected from an object (which causes and is not a good source of light (which causes Iambient). The current generated by the photodiode is due to ambient light The resulting part introduces a Μ composition in the diode current. In general, 'the DC composition may cause an error, which has the risk of saturating the front stage of the detector. _point of view, DC The correction loop 3〇8, which is provided parallel to the photodiode 3Q2, mimics the inductor and thus suppresses the DC composition of the diode current due to ambient light. Again, the DC correction Loop 308 also corrects the Dc composition without adding significant noise at the modulation frequency (for example, 5 MHz). The DC correction loop 308 includes amplifiers gml (3〇4) and (4) and one A pair of capacitor resistors (cF, rf) connected at the opposite terminal of gml (304). Specifically, CfRf attenuates the noise transfer function of gml (3〇4). Connected to resistor Rf The reference voltage Vref (for example, ground) establishes the bias point of the photodiode 3〇2 It is an important factor for the operation of a piN photodiode. In addition, gm2 is adaptively changed by adjusting its bias voltage to adjust/control/lower (4) spectral density & H > (3〇6) will adapt to the change of the ambient current, so that the noise contribution of the sink correction circuit 3(10) will be properly maintained below the noise contribution of the ambient light itself. Specifically, when the value of the ambient current changes The value of Chat 2 will be changed based on the bias applied by the output of grnl to ensure that the noise level of circuit 300 is not too noticeable. In one aspect, the DC correction circuit 3〇8 is ideally The DC conversion function will be zero at the photodiode node (N), and no DC can be passed through the remaining circuitry, for example, the voltage amplifier(s), filter(s) Furthermore, because the 〇 (: correction circuit 3 〇 8 imitates / acts as an inductor, it will provide a short circuit to the ground for the DC component. Accordingly, the DC correction circuit 308 is at Dc Will produce a zero point and prohibit the DC group The signal enters the front stage of the sensor (for example, a voltage amplifier(s). The signal output from the circuit 300 is supplied to the (equal) voltage amplifier, and further assists in proximity/motion debt testing. Analog and/or digital signal processing ◎ Furthermore, the output signal does not include a DC component caused by ambient light, and thus the front stage is protected from saturation. Furthermore, the loop gain of the DC correction loop 308 Can be calculated as follows: -gml (l + 5CFi?F) sCj^ sC pRp

Loopgain = where Capacitance of CF Capacitor CF 314; Resistance of RF Capacitor RF 3 12; 17 201142568 Gm2 Gain of Gamm2 Gain; C 〇3 1 0 Capacitance of Capacitor 3 〇2; constant. According to one embodiment, Rf 3 12 can be implemented as a Metal-Oxide Semiconductor (MOS) transistor capable of tracking gm2 (3〇6) with temperature. The MOS transistor will be there! ^ΕΙ) A more accurate frequency response control is achieved in the loop near the modulation frequency. The tracking technique is described in detail in the US Patent Application No. 4458212 to Brehmer et al. for the amplifier compensation. The title of the case is "COMPENSATED AMPLIFIER HAVING POLE ZERO TRACKING", It is incorporated by reference. Furthermore, the Rj? tracking of §〇12(3〇2) provides better control of the loop frequency response with temperature and process. Referring to Figure 4, there is shown another aspect of a low noise Dc correction circuit for use in TOF measurement in accordance with a perspective of the specification disclosed herein. Further, for example, DC The correction loop 4〇2 is capable of controlling the signal noise ratio (Signai.t()_Noise Rati., SNR) at a particular frequency (for example, modulation frequency (5 MHz)) and is reduced/removed in response to ambient light. It consists of DC in the diode current generated by the photodiode 302. Similar to the DC correction circuit 3〇8, the DC correction circuit 4〇2 is provided in parallel with the photodiode 3〇2 to compensate for the diode generated by the ambient light incident on the photodiode 302. Current. Again, the Dc correction back 02 will also mimic/become an inductor and thus provide a path to the ground for the composition. Specifically, the Dc correction loop is at 18 201142568

A zero point is generated at the DC and the dc component signal is prohibited from entering the sensing bandit level (e.g., voltage amplifier(s)). For example, a non-inverting input of a first amplifier gm 1 (304) may be connected to a reference voltage (Vref), for example 'grounded'; and the reverse input may be connected through a resistor RF 312 To node N. Further, Vref connected to the non-inverting input of the amplifier establishes a bias point of the photodiode 302. Progress 5, a capacitor cf314 will be incorporated into a feedback loop of gml (304) '俾 (^1^ will attenuate the noise conversion function of §1111(3()4). The output of gml(3〇4) is also supplied to the non-inverting input of gm2(3〇6) and used to control the bias of gm2(3〇6). Accordingly, when the value of the ambient current is changed to 'inflammation When the value of gm2 (3〇6) is changed, the noise introduced by the DC correction circuit 402 will be less than the noise introduced by the ambient current. In one of the views, the Rf 312 can be implemented. For a M〇s transistor, its t with > benefits and processes provide better control of the loop frequency response. Indeed, the MOS transistor is capable of tracking gm2 (3〇6) with temperature and A more accurate frequency s in the loop in the vicinity of the LED modulation frequency is to be controlled. The tracking technique is described in detail in the U.S. Patent Application Serial No. (U S 44,582, [2) to Brehmer et al. This is incorporated herein by reference. Figure 5 shows an example frequency domain curve of effective photodiode impedance in accordance with one aspect of the present invention. Figure 5 〇〇β In circuit 3〇〇 and/or 4〇〇, photodiode 302 is capable of converting incident light into a current. The effective impedance of the photodiode, |Zdiode|, is plotted against the frequency. 5. In addition, the 201142568 effective impedance ' |Zdicdej, can also calculate the following gm2

Vin lin gml + sCfRf +1 where

Vin is the input voltage; lin is the input current;

The capacitance of the Cf capacitor cF 314;

The resistance of the Rf-type resistor rf 3 1 2; the gain of the gm2-type amplifier gm2; the capacitance of the CD 310-based photodiode 3〇2; and the S-system constant. As seen in diagram 500, at ultra low frequencies, the effective impedance of the photodiode, |Zdiode|, is zero. In other words, at low frequencies, no voltage is generated at node N. Further, the effect of the ambient light can be seen from the characteristic curve of the frequency response of the sink correction loop (3〇8 and/or 402). Furthermore, the impedance represents the gain, which is considered to be zero in the Dc process (this means that the DC will be completely removed by the DC correction circuit 3〇8 and/or 4〇2, and the gain will increase as the frequency increases. And at the desired frequency, the gain will be significantly higher than DC. In the step - at a specific frequency (f, to f2), the frequency response will first stagnate, and then roll again (at G). In general, if the necessary signal is provided within the stagnation frequency range (for example, in response to a signal generated by light reflected from the object), it will pass normally. In other words, the necessary signal and The attenuation coefficient between DCs is very noticeable between fi and G. 20 201142568

Referring now to Figure 1 of the accompanying drawings, an exemplary circuit 6 of a _pM snubber channel oxide semiconductor device is implemented in a Dc correction loop for DC attenuation in accordance with an aspect of the present invention. According to an embodiment, gm2 (306) can be implemented as most of any pM〇s device, for example, but not subject to (d) PM〇S transistor pass. The bias of the PM〇s electro-crystals 〇6 is controlled by the output of gml, as shown in Figures 3 and 4. The noise caused by the dc correction loop is dominated by the value of gm2 (the gain of pM〇s transistor 3 (8)). Accordingly, if the value of gm2 increases, the power spectral density noise generated by the DC correction loop will increase. By adapting the system to change the value of the card 2, the DC correction circuit ensures that the noise caused by the relationship of the PMOS transistor 306 is substantially less than the noise caused by the ambient current. Moreover, the bias voltage of the PMOS transistor 306 is also adaptively changed based on the ambient light signal to adaptively change the value of gm2 so that the noise caused by the PMOS transistor 306 is substantially It will be less than the noise caused by the 凛% apostrophe. Further, when the current source 602 drops, low noise is introduced at the low ambient signal; conversely, when the ambient signal increases, the shot noise is dominant. However, the noise caused by the D C t positive loop is always less than the noise caused by the ambient current. In one aspect, the PMOS transistor 3〇6 may comprise a more complex circuit element (for example, a complex amplifier) than a field-effect transistor (FET), such that The conductivity of complex elements can be controlled and scaled. The output current is controlled by the PMOS transistor 306, which is then controlled by the amplifier gml 21 201142568. Furthermore, the amplifier gml will first compare the reference voltage (for example, ground) with the feedback from the output and then amplify the difference. If the feedback voltage is lower than the reference voltage, the gate of the pM〇S device will be pulled low, allowing more current to pass and increasing the output voltage. If the feedback voltage is higher than the reference voltage, the gate of the PM〇s device is pulled high, allowing less current to pass and lowering the output voltage. Figure 7 illustrates method steps and/or flowcharts in accordance with the main teachings disclosed herein. To simplify the explanation, the method steps are described and illustrated as a series of actions. It should be understood and appreciated that the present invention is not intended to be in the <Desc/Clms Page number> Other actions not mentioned and described. Moreover, it is not necessary to use all of the illustrated acts to implement the method steps in accordance with the subject matter disclosed herein. Moreover, those skilled in the art will understand and appreciate that such steps can also be represented by a series of interrelated states via a state diagram = or by multiple events. In addition, it should be further understood that the method steps disclosed in the specification and the entire specification are as follows: and in the manufacture of goods, to assist in the steps of the computer. The article of manufacture used in this document is intended to be a computer program obtained at any f-reading device or computer-readable material. Difficulty Figure 7 is not able to distinguish the distance or distance of an object and will not let people from + 疋 赞 赞 赞 m Step 700. In general, method step 7 can be used in a variety of applications, such as, but not limited to, consumer electronic devices (eg, cellular phones, laptops, media players, gaming systems) , night vision systems, etc.), mechanical systems (for example, door/window mechanisms), industrial automation systems, robots, etc. At 702, for example, a signal input to a transmitter (e.g., an IR LED) may be modulated at a high frequency in the range of millions of Hertz (e.g., 1 MHz to 50 MHz). For example, most of any modulation techniques can be used for modulation. At 704, the frequency modulated signal may be used by the IR LED to illuminate. In general, the range of the IR LEDs can be selected depending on the application (for example, up to 2 meters). The emitted IR signal is reflected back from the object(s) (moving and/or stationary) in the light range, and the reflected signals are combined with ambient light (for example, sunlight, Fluorescent, electric light, light bulbs, etc.) are received at an optical sensor (for example, an 'IR sensor'). At 7〇6, the signal is received from the sensor; and at 7〇8, the DC in the received signal is composed (for example, due to ambient light incident on the sensor) Generated) will be attenuated' while controlling the noise caused by the attenuation circuit. Further, at 710, the signal is processed, for example, amplified, filtered, demodulated, etc., to confirm the location of the object and/or the location at which the motion occurred. Typically, the signal is amplified by the use of one or more amplifiers and demodulated by the use of a quadrature amplitude demodulator. Furthermore, the phase data is also found based on the demodulation. Then, the phase data can be used to confirm the proximity of an object or the motion of 201142568. To provide additional background information for the various aspects of the present specification, FIG. 8 shows an exemplary functional block diagram of architecture 800 of the present invention. In one of these points, the systems disclosed herein (for example, Figures 4 and 4) can be used with or without integrated ambient light sensors (Ambient Light Sensor, ALS). A reflection-based approach to proximity and motion detectors. The rack 800 includes an LED and associated driver circuitry (not shown in the 'not shown'), a photodiode sensor 302, an analog front stage and signal processing 8〇2, data conversion Circuitry (for example, analog to digital converter 804), digital control and signal processing 8〇6 (for example, complex computer programmable logic devices (c〇mputer)

Programmable Logic Device, cpld)), interface circuitry (not shown in the figure, not shown), and/or result display (not shown, not shown). The architecture will adaptively optimize sensitivity and power for a given environment. Furthermore, the architecture will also provide significant performance improvements and reduce the risk of pre-saturation. According to an aspect of the invention, the architecture 8〇〇 includes a pre-stage (Fr〇nd

End ' FE) 'It includes a Trans-Inductance Amplifier (TIAh, for example, the DC correction circuits 300, 400, and 600 disclosed above can be implemented in the DC correction circuit of the segment 8〇8 In addition, the DC correction circuit 116 attenuates the DC component of the electrical signal generated by the detector (for example, an error signal). Further, the DC correction circuit 16 causes a noise meeting. Less than the noise caused by one or more signal processing components in the front stage of the reflection-based proximity detector (for example, 24, 2011, 468, 'Amplifier 810, analog FE 802, ADC 804, ..., etc.). The output of the front stage 808 may be subject to multiple levels of voltage boosting to maximize the SNR of the output signal. For example, the voltage gain will be received by the signal from the previous stage 808 (which contains the amount to be measured The size of the measured signal is adaptively set. The interference is dynamically corrected in the measurement to improve sensitivity (for example, by the Dc correction circuit 116^ the architecture 800 may still contain : A low pass filter (Low Pass Fiiter, LPF) demodulator (not shown in the figure, not shown) for frequency demodulation; converter (ADC) 8〇4; Universal seriai Bus (USB) processor for control &face; and a computer programmable logic device (CPLD), which contains several modules. Furthermore, digital signal processor (Digital Signal Pr) The 〇cess(>r, DSP) 8〇6 also processes the digital signal to confirm that the proximity of the object, the motion of an object, and/or an object is present within the sensing range of the sensor 302. The architecture 800 of the present invention can be used in many applications, including computers, automobiles, industrial, television displays, and other applications. For example, 'the architecture _ 彳 for (4) - the user has entered the room And automatically wake up the laptop in sleep mode and enter the active mode, so that the user can use it. According to the present invention - the view 'Butterfly 800 can be in the range of up to i to 2 meters Implement motion sensing and near Sensing. According to another aspect of the present invention, the architecture of the present invention is capable of implementing its operation 25 201142568 using less than twenty milliwatts (mw) of power. In one embodiment of the present invention, the entire architecture 800 will be implemented in a single-integrated circuit chip (IC) along with the (four) driving n (four) system and the LED. In another embodiment of the invention, in addition to the LED driver circuit system and the LED Outside (they may be implemented outside of the IC) 'all components of the architecture 800 can be implemented in the Ic. In still another embodiment of the present invention, various components of the architecture 8 can be disposed inside or outside the 1C. The various examples of the invention have been described above. Of course, it is not possible to clarify various combinations of elements or method steps that can be considered for the purpose of illustrating the main content claimed herein; however, those skilled in the art will appreciate that the present invention may have many further The combination and arrangement. Accordingly, the main content claimed herein is intended to cover all such changes, modifications, and variations that fall within the spirit and scope of the appended claims. In particular, and in connection with the functions of the elements, devices, circuits, systems, and the like described above, unless specifically stated otherwise, the structural aspects are not equivalent to the embodiments disclosed herein. The structure of the exemplary aspects of the main content claimed herein, however, the various terms used to describe such elements (including references to "components") are intended to correspond to the specified functions of the elements described. Any of the components (for example, in terms of: equivalent in terms of 'in this respect', the invention includes a package of money and a computer readable medium having a medium for reading The actions of the various methods claimed in this document and/or the computer executable instructions of 201142568. This article has explained the system/circuit/module mentioned above for the interaction between several components. It is understood that such systems/circuits/modules γ and 7L components may include such elements or specified sub-elements, such as _ portions of the specified _ or sub-components, and/or additional components, and According to the various arrangements and combinations described above, the sub-elements can also be implemented as components that are communicatively coupled to other components, rather than being incorporated into the parent component (hierarchical). a system, or multiple elements may be twisted into a single element to provide a collective function; or, may be divided into several separate sub-elements' and any one or more intermediate layers (eg, a management layer) may be provided. It is used to communicate (4) to such sub-elements to facilitate U-ports. Any of the elements described herein may also interact with one or more other elements that are not commonly described herein but are generally known to those skilled in the art.爯 , μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ μ The positive resistance of the positive band Α β, the capacitor may have any suitable capacitance, the amplifier may provide any suitable gain, etc. In addition, although this article is only possible for the number One of the basins in the embodiments reveals a particular feature of the invention; however, in a fixed or special application, this feature can be combined with the 仃 amp amp · · · 仍 仍 仍 仍 仍 仍 仍 仍 仍 仍One or more other features, and are said to be quite advantageous. Also, to some extent, the words "including", "having", "containing", etc., are used in the detailed description or patent application scope herein. Words, and other similar terms, and open transitions are similar to (4) "including". These words are all hoped that 27 201142568 is a Baogu type. It does not exclude any additional or other elements. [Simplified illustration] Figure 1 does not An exemplary system for reducing direct current (DC) saturation in the front stage of a long range proximity detector that does not introduce significant noise. Figure 1 shows an integrated circuit (IC) An exemplary system of wafers that corrects for error signals generated by an optical sensor due to ambient light during distance sensing. Figure 3 is an exemplary circuit diagram for compensating for direct current (DC) current generated by an optical sensor. 4 is an exemplary circuit of a low noise DC correction circuit that is utilized in time-of-flight (TOF) measurements in accordance with one aspect of the specification disclosed herein. Figure 5 is an exemplary frequency domain plot of effective photodiode impedance in accordance with an aspect of the present invention. Figure ό shows an exemplary circuit for implementing a P-Ch_el Metal-Oxide-Semiconductor (PMOS) device in a DC correction loop for DC attenuation. What is not shown in Figure 7 is an exemplary method step of being able to resolve the distance of an object or the distance at which the motion occurs while ignoring the effects of ambient light incident on a sensor. An exemplary functional block circle of the architecture of the present invention is shown in FIG. [Major component symbol description] 28 201142568 100 102 104 106 108 110 112 114 116 118 202 204 206 300 302 304 306 308 310 312 314 400 402 500

Example System IR LED IR Sensor or PIN Detector LED Driver Modulated IR Signal Sensing Object Reflection

Other signal or environmental backscatter DC correction loop pre-stage circuit 1C Amplifier distance decision circuit example circuit photodiode / sensor amplifier amplifier DC correction loop capacitor resistor capacitor example circuit DC correction loop example frequency domain curve 29 201142568 600 Example Circuit 602 Current Source 700 Example Method 702-710 Step 800 Architecture 802 Analog Front Stage 804 Analog to Digital Converter 806 Digital Signal Processing 808 Preamp 810 Amplifier 30

Claims (1)

201142568 VII. Patent application scope: 1 - A device comprising: a sensor; and a DC (DC) correction circuit coupled to the sensor; wherein the DC correction circuit is used to reduce a part of a DC error generated by an environmental signal incident on the sensor; and the noise correction density generated by the DC correction circuit is lower than that generated by one or more signal processing components included in the pre-stage Spectrum density. 2) The device of claim 1, wherein the D C correction circuit is coupled in parallel to the sensor. 3 _ The device of claim 1, wherein the sensor is a light diode. 4. The device of claim 1, wherein the DC correction circuit mimics an inductor. The apparatus of claim 1, wherein the DC correction circuit includes a first amplifier that controls a bias voltage of a second amplifier. 6. The device of claim 5, wherein the DC correction circuit includes a resistor and a capacitor pair that attenuates a ff conversion function of the first amplifier. 7. The device of claim 5, wherein the second amplifier comprises at least one of a P-channel metal oxide semiconductor (PMOS) device or a buffer. 8. The device of claim 5, wherein the resistor is implemented as a metal oxide semiconductor (MOS) transistor. 31. The device of claim 5, wherein an output of the second amplifier provides a feedback as an input to the first amplifier. 10. The device of claim 3, further comprising: a light emitting diode (LED) that emits light associated with a frequency modulated signal, wherein the light is reflected from an object and the sensor receives At least a portion of the reflected light from the object. 11 . A method of reducing direct current (DC) saturation in a sensor system, comprising: generating a sensor signal comprising a DC component; substantially subtracting the DC component from the sensor signal; and adapting The value of a thermal noise introduced during the subtraction step is reduced 俾 such that the thermal noise value is less than a different thermal noise value introduced by subsequent signal processing. 12_ The method of claim 11, further comprising: frequency modulating an electrical signal; and emitting light associated with the frequency modulated signal. 13. The method of claim 12, further comprising: at the sensor' receiving at least a portion of the light reflected from one or more objects within the range of light. 14. The method of claim 13 wherein the adaptively reducing the thermal noise value comprises adaptively controlling the amount of thermal noise introduced at a modulation frequency during the subtracting step. 15. The method of claim 13, further comprising: processing the sensor signal to confirm at least one of: one distance of the one or more objects 32 201142568 or a distance at which a motion occurs. The method of claim 11, wherein the subtracting comprises emulating an inductor that removes or reduces at least the DC composition. 17. A system comprising: a sensor that generates an electrical signal comprising a portion of a low frequency component based on ambient light and a phase frequency component based on light reflected from an object; Parallel to the feedback loop of the sensor, which transmits the high frequency component to a level device and at least eliminates or reduces the low frequency component without introducing a signal in a preamplifier of one of the s Xuan systems Handling thermal noise at one of the thermal noise introduced by the circuit system. 1 8 · The system of claim 7, wherein the feedback loop comprises a resistor and a capacitor pair, which attenuates a noise conversion function of the first amplifier, the first amplifier controls a first A bias of the two amplifiers. 19. The system of claim 5, wherein a cathode of the sensor is coupled to a non-inverting input of the first amplifier; the resistor is coupled to a reference voltage and a first amplifier Between the inverting inputs, the capacitor is coupled between an output of the first amplifier and the inverting input of the first amplifier; the output of the first amplification is coupled to a reverse of the second amplifier The input, and an output of the first magnifying thief, are fed back to the cathode of the sensor. 33. The system of claim 18, wherein the circuit is connected between the cathode of the sensing and an inverting input of the first amplification thin; the electric grid is connected An output of the first amplifier is coupled to the inverting input of the first amplifier; a non-inverting input of the first amplifier is coupled to a reference voltage; the output of the first amplifier is coupled to the second A non-inverting input of the amplifier; and an output of the second amplifier is fed back to the cathode of the sensor. Eight, schema · (such as the next page) 34