Optical sensor for feedback on light quantity control and method for controlling the same

Abstract

The present invention relates to a light sensor that performs feedback for light intensity control and a control method thereof. A light sensor according to one embodiment of the present invention may include: a light-emitting driving unit that determines a light-emitting parameter including at least one of a light-emitting time, a light-emitting frequency, and a light-emitting amount according to a control signal and transmits the determined light-emitting parameter to a light-emitting unit; and a light intensity control unit that feeds back the control signal, which is linked to the intensity of an input signal received from a light-receiving unit, to the light-emitting driving unit.

Description

Technology Field

[0001] The present invention is a light sensor that performs feedback for light intensity control and a method for controlling the same. Background Technology

[0002] Recently, optical sensors are being commercialized by integrating light-emitting elements, photodetectors, and semiconductor ROICs into a single package. In particular, for True Wireless Stereo (TWS) devices, product miniaturization and low power consumption have become key design elements for ICs, following performance. To accommodate a size small enough to be worn in the ear and to house complex components for various functions, miniaturization and low power consumption have become increasingly important factors in recent years. However, given the limitations on the size of light-emitting and photodetectors, miniaturization of the ROIC and securing low-power performance are crucial.

[0003] As illustrated in FIG. 1, in the case of a conventional ROIC, the driver (3) controlling the light-emitting unit (10) and the AFE (1) and ADC (2) processing the amount of light received by the light-receiving unit (20) were separated, and the controller (4) controlled the driver (3) to drive it with a preset light-emitting time and amount of light. Although the above configuration was intuitive for emitting light for a set time and changing the amount of received light into a digital value, it had the problem of a large area and high power consumption. In particular, when attempting to expand the number of bits of the digital value to accurately and finely control the light-emitting signal in a conventional semiconductor ROIC, the area of ​​the semiconductor ROIC increased rapidly, making it difficult to perform control of more than 1 bit.

[0004] In addition, as shown in FIG. 2, the time value input to the driver (3) is fixed, so the driver (3) drives a fixed current pulse according to the input enable, and the receiving unit (20) can receive a photo current in a reduced state depending on the difference in distance from the object. In order to integrate the received photo current and convert it into voltage, an AFE (1) implemented with complex analog blocks such as a PRE-gain amp or integrator must be used, which has the problem of high power consumption and occupying a large area.

[0005] The problem is that the AFE (1) is complex and large because the received photocurrent must be integrated as is, but the ADC (2) must also perform excessive sampling to digitally process the integrated voltage, and consequently, power is consumed excessively, resulting in a problem of even greater power consumption.

[0006] In addition, when the switched voltage (ADC input) exceeds the saturation value, the controller (4) can be reset to reduce the pulse width of the light-emitting element (10) through the determined digital value, but when the received photocurrent does not exceed the saturation, there is no way to control the pulse width of the light-emitting element according to the received photocurrent.

[0007] Meanwhile, conventional patent documents disclose a comparator circuit that compares a light-emitting unit and a PWM signal driving the light-emitting unit with a control waveform, but they do not disclose a configuration in which feedback is received using the photocurrent received by the comparator circuit, so the above problem could not be solved.

[0008] (Patent Document 1) KR 10-2226432 B1 The problem to be solved

[0009] To solve the conventional problem, the present invention aims to provide a light sensor and a control method thereof that perform feedback for light intensity control, which can continuously and precisely control the pulse width (on-time width) of the light-emitting unit by providing a control signal linked to a light signal received from a light-receiving unit to a light-emitting driving unit. means of solving the problem

[0010] As a first aspect of the present invention, a light sensor performing feedback for light intensity control according to one embodiment of the present invention may include: a light emission driving unit that determines a light emission parameter including at least one of a light emission time, a light emission frequency, and a light emission amount according to a control signal; a light emission unit that emits light according to the determined light emission parameter; a light receiving unit that receives light emitted by the light emission unit; and a light intensity control unit that feeds back the control signal, which is linked to the intensity of an input signal received by the light receiving unit, to the light emission driving unit.

[0011] In addition, as a second aspect of the present invention, a semiconductor ROIC for a light sensor according to one embodiment of the present invention may include a light emission driving unit that determines a light emission parameter including at least one of a light emission time, a light emission frequency, and a light emission amount according to a control signal, and transmits the determined light emission parameter to a light emitting unit, and a light amount control unit that feeds back the control signal, which is linked to the intensity of an input signal received from a light receiving unit, to the light emission driving unit.

[0012] Meanwhile, as a third aspect of the present invention, a control method for a light sensor that performs feedback for light intensity control according to one embodiment of the present invention may include: a step of determining a light emission parameter including at least one of a light emission time, a light emission frequency, and a light emission amount according to a control signal, and transmitting the determined light emission parameter to a light-emitting unit; and a step of feeding back the control signal, which is linked to the intensity of an input signal received from a light-receiving unit, to a light-emitting driving unit.

[0013] In addition, as a fourth aspect of the present invention, a computer-readable recording medium storing a computer recording medium for executing the above-described method on a computer may be provided. Effects of the invention

[0014] According to one embodiment of the present invention, a semiconductor ROIC can be implemented with a simple integrator and a simple ADC that omits the sampling and hold processes, thereby reducing the ROIC size and power consumption and lowering costs.

[0015] In addition, the signal from the light receiving unit can be linked to the light emitting driver to control the light emission parameters of the light-emitting element in real time, and since multi-bit control can be performed without increasing the ROIC size, noise removal is easy and the light-emitting unit can be controlled in detail. Brief explanation of the drawing

[0016] Figure 1 is a block diagram briefly illustrating the configuration of a conventional optical sensor. Figure 2 is a waveform diagram briefly illustrating the signal waveform of a conventional optical sensor. FIG. 3 is a block diagram briefly illustrating the configuration of a light sensor according to one embodiment of the present invention. FIG. 4 is a timing diagram briefly illustrating the signal waveform of a light sensor according to one embodiment of the present invention. FIG. 5 is a block diagram briefly illustrating the configuration of a light sensor according to another embodiment of the present invention. FIG. 6 is a timing diagram briefly illustrating the signal waveform of a light sensor according to another embodiment of the present invention. FIG. 7 is a block diagram briefly illustrating the configuration and signal input / output of a light-emitting driving unit according to one embodiment of the present invention. FIG. 8 illustrates a specific circuit diagram of a light-emitting driving unit according to one embodiment of the present invention. FIG. 9 is a timing diagram briefly illustrating the signal processing of a light-emitting driving unit according to one embodiment of the present invention. FIG. 10 illustrates a flowchart for a control method of an optical sensor according to one embodiment of the present invention. Specific details for implementing the invention

[0017] Embodiments of the present invention will be described below with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited only to the embodiments described below. The shapes and sizes of elements in the drawings may be exaggerated for clearer explanation, and elements indicated by the same reference numerals in the drawings are the same elements.

[0019] FIG. 3 is a block diagram briefly illustrating the configuration of a photosensor according to one embodiment of the present invention, and FIG. 4 is a timing diagram briefly illustrating the signal waveform of a photosensor according to one embodiment of the present invention.

[0020] As illustrated in FIG. 3, a semiconductor ROIC (100) for a light sensor according to one embodiment of the present invention may include a light emission driving unit (110) that determines a light emission parameter including at least one of a light emission time, a light emission frequency, and a light emission amount according to a control signal and transmits the determined light emission parameter to a light emission unit (10), and a light amount control unit (200) that feeds back the control signal, which is linked to the intensity of an input signal received from a light receiving unit (20), to the light emission driving unit (110).

[0021] According to one embodiment of the present invention, a light sensor can be manufactured by implementing a semiconductor ROIC (100), a light emitting unit (10), and a light receiving unit (20) in one PACKAGE. That is, the light sensor according to one embodiment of the present invention may include a light emitting driving unit (110) that determines a light emitting parameter including at least one of a light emitting time, a light emitting frequency, and a light emitting amount according to a control signal, a light emitting unit (10) that emits light according to the determined light emitting parameter, a light receiving unit (20) that receives light emitted by the light emitting unit (10), and a light amount control unit (200) that feeds back the control signal, which is linked to the intensity of the input signal received by the light receiving unit (20), to the light emitting driving unit (110).

[0022] At this time, according to one embodiment of the present invention, the light receiving unit (20) can output at least one bit logic, and the light emitting driving unit (110) can control the on / off of the pulse generator (112, shown in FIG. 7) to adjust the width, frequency, etc. of the current or voltage pulse to be output. Through this, the light emission time can be finely adjusted, making it possible to perform accurate feedback control.

[0023] Additionally, a light intensity control unit (200) according to one embodiment of the present invention may include an integrator (210) that converts a current proportional to the intensity of an input signal received by the light receiving unit (20) into a voltage, and a comparator (220) that compares the converted voltage with a reference voltage and outputs at least one bit of output bit.

[0024] In addition, a light-emitting driving unit (110) according to one embodiment of the present invention is connected to the comparator (220), and can control the on / off switching according to a control signal based on the output bit of the comparator (220) to adjust the pulse width of the current.

[0025] Specifically, as illustrated in FIG. 3, a light-emitting unit (10), for example, a VCSEL (Vertical-Cavity Surface-Emitting Laser), converts electrical energy into light energy according to a PWM current pulse received from a light-emitting driving unit (110) and emits light.

[0026] This is received by the light receiving unit (PD, 20), and a photocurrent is generated by the electron-hole pair generated by the received light energy, and the light intensity control unit (200) can determine whether the distance to an object is close or far depending on the received photocurrent.

[0027] For example, if the distance from the object increases, the photocurrent received by the light receiving unit (20) decreases, and if the distance decreases, the photocurrent may increase.

[0028] At this time, if the input photocurrent decreases, the light emission must be increased to detect the location of the object because the object is located far away; if the input photocurrent increases, the object is located close, so a large light emission is not strictly necessary, and thus the light emission or emission time can be reduced to reduce power consumption.

[0029] That is, according to the photocurrent received from the light receiving unit (20), the light quantity control unit (200) determines a control signal to control light emission parameters including light emission time, light emission frequency, light emission amount, etc., and can feed back the control signal to the light emission driving unit (110).

[0030] As illustrated in FIG. 4, the light-emitting driver (110) starts driving based on Enable (En) transmitted by the controller (120) and can generate current pulses according to the on / off signal by controlling the on / off inside the light-emitting driver (110).

[0031] In one embodiment, the current pulse may be a PWM current pulse.

[0032] When the above current pulse strikes an object and is received, a photocurrent illustrated in FIG. 4 can be obtained, and the light intensity control unit (200) can signal process information of the received photocurrent and transmit the signal-processed control signal back to the light-emitting driving unit (110) to control the light-emitting state of the light-emitting unit (10).

[0033] A light intensity control unit (200) according to one embodiment of the present invention may include an integrator (210) and a comparator (220), and may input the acquired photocurrent to the integrator (210) to obtain a voltage, and input the voltage to the comparator (220) to obtain an output bit.

[0034] In one embodiment, the integrator (210) can generate voltage in a simple integrator (1 / s) manner without the need to use a complex analog block such as a pre-gain amp, and can also quickly obtain voltage for the received photocurrent by omitting sampling and hold and implementing it in a simple comparator operation using a comparator (220).

[0035] Additionally, when the above voltage is input to a comparator (220), the comparator can compare the reference voltage with the received voltage and output the comparison result as n bits. Preferably, the n bits may be 1 bit.

[0036] As illustrated in FIG. 4, for a preset reference voltage, the comparator (220) can output a digital signal 1 (high section) if the input voltage exceeds half (1 / 2Ref) of the reference voltage, and output 0 (low section) if it does not exceed it. That is, the light-emitting driving unit (110) can be controlled with a single 1-bit containing information on the amount of light received by the light-receiving unit (20). This modulates the control signal to be fed back.

[0037] That is, the light receiving unit (20) can output 1 to n bit logic, and the comparator (220) can process the received input voltage to output an n bit, preferably 1 bit, digital signal.

[0038] Through this, the light intensity control unit (200) can generate a digital signal, which is a control signal to be transmitted to the light-emitting driving unit (110), using light-related information received from the light receiving unit (20).

[0039] The above control signal can finely adjust the light emission time (on time width), which is the current pulse width, by performing internal on / off control of the light emission driving unit (110).

[0040] Meanwhile, according to one embodiment of the present invention, as shown in FIG. 3, the light intensity control unit (200) may further include a digital signal processing unit (230) and can receive n bits, preferably 1 bit, output from a comparator (220) and generate a desired digital value of bits.

[0041] Specifically, as illustrated in signal waveforms 4 and 5 of FIG. 4, the output of the comparator (220) is determined according to the slope of the input signal waveform of the comparator (220). If the distance to the object is close and the photocurrent signal is large, the slope at the input of the comparator (220) increases, and if the distance to the object is far and the photocurrent signal is small, the slope at the input of the comparator (220) decreases. Even if the photo amount of the light-emitting part (10) is the same, the slope of the input signal of the comparator (220) may differ.

[0042] When the slope increases, the time exceeding 1 / 2 Ref becomes longer, and the high section of the output of the comparator (220) becomes longer; when the slope decreases, the time exceeding 1 / 2 Ref becomes shorter, and the high section of the output of the comparator (220) becomes shorter. That is, when the high section and the low section are viewed as one cycle, the length of the high section changes, and the cycle changes, in other words, a 1 bit is obtained in which the frequency changes.

[0043] That is, the period of the signal that is repeatedly generated at the output of the comparator (220) changes, and if counting is performed for a long time to secure multi-bits, bits with different frequencies are generated depending on the distance between the object and the light sensor, and the digital signal processing unit (230) can count the bits with different frequencies.

[0044] In one embodiment, the digital signal processing unit (230) may count the bits received for a certain period of time using a simple counter and output a digital signal of the desired bit. In this case, even if a small-sized and slow-speed ADC is used, bits with different frequencies can be obtained.

[0045] Alternatively, as another embodiment, the digital signal processing unit (230) can perform noise shaping by oversampling the input signal in a filter and inputting the oversampled 1 bit or multi-bit to a delta-sigma ADC, and the delta-sigma modulator can output a bitstream digital signal which is a 1-bit signal.

[0046] That is, a 1 bit with a changing frequency can be secured in a short time to form a multi-bit and transmitted to the light-emitting driving unit (110).

[0047] In the case of a delta-sigma ADC, sampling must be performed at a frequency much faster than the output of the comparator (220), and counting the number of high intervals must be done in a shorter time. To obtain more 1s, the sigma-delta ADC must sample at a frequency faster than the frequency of the 1 bit, and digital signal processing can be performed using oversampling and decimation.

[0048] Accordingly, the digital signal processing unit (230) can transmit a multi-bit with an expanded number of bits in the above-described method to the light-emitting driving unit (110) to control the pulse width generated by the light-emitting driving unit (110) in more detail.

[0050] Alternatively, according to another embodiment of the present invention, the digital signal processing unit (230) may further include an up-down counter to search for the on-off time of the light-emitting driving unit (110).

[0051] FIGS. 5 and 6 are block diagrams briefly illustrating the configuration of a photosensor according to another embodiment of the present invention and timing diagrams briefly illustrating the signal waveform of the photosensor.

[0052] As illustrated in FIG. 5, a digital signal processing unit (230) according to another embodiment of the present invention may further include an up-down counter. The up-down counter can control the pulse on / off time to be output from the light-emitting driving unit (110) according to the output signal of the received comparator (220), for example, if there is a toggle, the pulse on time can be lowered, and if there is no toggle, the pulse on time can be increased.

[0053] As illustrated in FIG. 6, the comparator (220) may output a toggle only for signals that exceed a reference voltage and transmit 1 bit of the toggle to the digital signal processing unit (230). The digital signal processing unit (230) can check whether a toggle is generated through an up-down counter, and if there is no toggle, it is known that the current pulse width received by the light receiving unit (20) has not exceeded the reference voltage, and if there is a toggle, it is known that the current pulse width received by the light receiving unit (20) has exceeded the reference voltage.

[0054] When the digital signal processing unit (230) counts whether a toggle occurs through an up-down counter and feeds back the counted on / off control signal to the light-emitting driving unit (110), the light-emitting driving unit (110) can control the on / off time.

[0055] As shown in FIG. 6, when the on / off time is initially turned on for N periods and no toggle occurs in the comparator (220), the next time can be increased to N+1 hours, and if no toggle still occurs, the next time can be increased to N+2. However, if a toggle occurs when the time is increased to N+3, the reference voltage is detected to have been exceeded, and the next time can be lowered back to N+2.

[0056] That is, by utilizing the information from the light receiving unit (20), an appropriate current pulse width can be directly searched, and the on / off time of the light-emitting driving unit (110) can be appropriately controlled. By performing feedback tailored to the current situation rather than a preset value, an accurate pulse can be detected, and at the same time, the SNR can be improved and power consumption reduced.

[0057] That is, the digital signal processing unit (230) can provide feedback to the control signal in various ways, such as increasing or decreasing the pulse width of the PWM current pulse to be output from the light-emitting driving unit (110) by 1 through the counted digital value, performing a binary search, or adding or subtracting the difference from the previous pulse width.

[0058] Accordingly, according to one embodiment of the present invention, the light intensity control unit (200) may further include a digital signal processing unit (230) that receives an output bit of a comparator (220), and may output a digital control signal that determines whether a reference voltage is exceeded according to the received output bit and determines whether to increase or decrease the pulse width of the current, and the light emission driving unit (110) may control a pulse generation unit (112) to increase or decrease the pulse width of the current according to the digital control signal.

[0059] Specifically, the digital signal processing unit (230) can output a control signal that increases the pulse width of the current when the output bit is 0, and output a control signal that decreases the pulse width of the current when the output bit is 1.

[0061] FIG. 7 is a block diagram briefly illustrating the configuration and signal input / output of a light-emitting driving unit (110) according to one embodiment of the present invention.

[0062] A light-emitting driving unit (110) according to one embodiment of the present invention can generate a pulse using a digital signal or digital value generated from a comparator (220) or a digital signal processing unit (230) and an Enable value of a controller (120).

[0063] The pulse generation unit (112) can generate a voltage pulse according to the Enable and a digital signal which is a control signal, and can generate a current pulse according to the voltage pulse generated by the driving unit (111). For example, it can output a PWM current pulse.

[0064] That is, the pulse generation unit (112) can control the pulse width or pulse frequency, etc., according to the received digital signal to control the light emission of the light-emitting element (10).

[0065] As illustrated in FIG. 7, the pulse generator (112) can control the output according to a clock, or can generate pulses using an internal delay without a separate clock.

[0066] However, when using a clock in the digital signal processing unit (230) implemented in Fig. 5, as described above, in order to obtain multi-bits and perform light intensity control, a very fast clock must be used, and in that case, power consumption may increase.

[0067] Accordingly, a pulse generation unit (112) as shown in FIGS. 8 and 9 can be implemented to secure a small-scale, low-power optical sensor and simultaneously secure multiple bits to perform detailed light intensity control. The illustrated multiplex block is illustrated using 10 bits as an example, and the scope of the claim is not limited to the number described above.

[0068] As illustrated in FIG. 8(a), the pulse generation unit (121) may include a block that adjusts the pulse width using MX[9:0]. That is, the light signal received from the light receiving unit (20) is input as a control signal processed by the light intensity control unit (200) and used as a select signal, and the n bits of the control signal are divided into MX[9], MX[8]... and input to form a signal path that performs matching downwards when a digital value 0 is input and upwards when a digital value 1 is input.

[0069] FIG. 8(b) shows one of the 127 select blocks shown in (a), which contains 127 buffers with 50 pico delays inside, and the multiplexer includes its own multiplexer delay, but this is not shown.

[0070] In the above buffer, the signal path is configured to flow downward when the digital signal is 0 and upward when the digital signal is 1, so that a value can be added whenever a digital signal 1 appears. Whenever a digital signal 1 is added, an output signal with a 50 pico delay added can be obtained. The output signal is input to a decoder to generate a start signal to be input to the driving unit (111).

[0071] As described above, the select block performs multiplex switching, and the ununiformity of the multiplex switching can be improved. Through this, it is possible to accurately perform uniformity or matching while adjusting 1000 delays in one step using a delay cell, and to generate pulses by adjusting even the minute width of the pulse without a clock.

[0072] FIG. 9 can perform a preset fixed MUX delay from the moment ENABLE appears through the start signal output from the select block used in FIG. 8(a) and the ENABLE signal received from the controller (120), and then add a pulse width determined to be 10 bits as determined in FIG. 8. This value is a value determined by the number of bits used in FIG. 9, and as an exemplary embodiment, the scope of the claim is not limited by the above value.

[0073] As an example, the fixed multiplexer delay may be omitted and a pulse width determined to be 10 bits may be generated directly.

[0074] Through the aforementioned structure, a small-scale, low-power optical sensor can be implemented, and light intensity control based on multi-bit is possible using only cell delay without using a clock that performs fast operation.

[0076] Meanwhile, FIG. 10 illustrates a flowchart of a control method for a semiconductor ROIC (100) for a light sensor according to one embodiment of the present invention.

[0077] A semiconductor ROIC control method (100) for a light sensor according to one embodiment of the present invention may include, as illustrated in FIG. 8, a step (S810) of determining a light emission parameter including at least one of a light emission time, a light emission frequency, and a light emission amount according to a control signal, and transmitting the determined light emission parameter to a light emitting unit (10), and a step (S820) of feeding back the control signal, which is linked to the intensity of an input signal received from a light receiving unit (20), to a light emission driving unit (110). Content that overlaps with the above description is omitted for clarity of explanation.

[0079] In addition, a semiconductor ROIC control method for an optical sensor according to one embodiment of the present invention may be produced as a program to be executed on a computer and stored on a computer-readable recording medium. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc. Furthermore, the computer-readable recording medium may be distributed across networked computer systems, allowing computer-readable code to be stored and executed in a distributed manner. Moreover, functional programs, codes, and code segments for implementing the above method can be easily inferred by programmers skilled in the art to which the present invention belongs.

[0080] In addition, in describing the present invention, a 'module' or 'part' may be implemented in various ways, for example, by a processor, program instructions executed by the processor, a software module, microcode, a computer program product, a logic circuit, an application-specific integrated circuit, firmware, etc.

[0081] The present invention is not limited by the embodiments described above and the attached drawings. The scope of rights is intended to be limited by the attached claims, and it will be obvious to those skilled in the art that various substitutions, modifications, and changes can be made within the scope of the technical concept of the present invention as described in the claims. Explanation of the symbols

[0082] 100: Semiconductor ROIC 110: Light-emitting driving unit 120: Controller 200: Light intensity control unit 210: Integrator 220: Comparator 230: Digital signal processing unit 10: Light-emitting part 20: Gwangbu

Claims

Claim 1 A light-emitting driving unit that determines a light-emitting parameter including at least one of a light-emitting time, a light-emitting frequency, and a light-emitting amount according to a control signal, and generates a current pulse applied to a light-emitting unit according to the determined light-emitting parameter; and a light-receiving unit that receives light emitted by the light-emitting unit; A light intensity control unit that feeds back a control signal to a light-emitting driving unit based on a photocurrent received from the light receiving unit; wherein the light intensity control unit comprises: an integrator that converts a current proportional to the intensity of an input signal received by the light receiving unit into a voltage; a comparator that determines an output such that the period or high interval length of the output signal varies according to the rate of change of the voltage signal over time by comparing the voltage signal output from the integrator with a reference voltage; a digital signal processing unit that generates a digital value by counting the repetition period or high interval length of the signal output from the comparator for a predetermined time and outputs a control signal to the light-emitting driving unit that increases or decreases the pulse width of the current pulse based on the generated digital value; and wherein the light-emitting driving unit comprises a pulse generation unit that finely adjusts the pulse width of the current pulse by selecting at least one of a plurality of delay paths according to the control signal from the digital signal processing unit. Claim 2 In claim 1, the light-emitting driving unit is a light sensor that performs feedback for light intensity control, which incrementally increases or decreases the pulse width of the current pulse by changing the selection of a delay cell or a selection path according to a digital control signal output from the comparator or the digital signal processing unit. Claim 3 In claim 2, the digital signal processing unit determines whether a reference voltage is exceeded based on the count result of a 1-bit bitstream, and outputs a digital control signal that increases or decreases the pulse width of the current pulse according to the determination result, thereby performing feedback for light intensity control on the optical sensor. Claim 4 In claim 3, the digital signal processing unit outputs a control signal that increases the pulse width of the current pulse when the count result of a 1-bit bitstream is less than a reference value, and outputs a control signal that decreases the pulse width of the current pulse when the count result is greater than or equal to the reference value, thereby performing feedback for light intensity control of the optical sensor. Claim 5 In claim 1, a semiconductor ROIC including the light-emitting driving unit and the light-intensity control unit, and a light sensor that performs feedback for light-intensity control in which the light-emitting unit and the light-receiving unit are integrated into a single package. Claim 6 In claim 5, the light intensity control unit is a light sensor that performs feedback for light intensity control by generating a 1-bit bitstream or a multi-bit digital value based on the photocurrent received from the light receiving unit. Claim 7 A method for controlling a light sensor that performs feedback for light quantity control, comprising: determining a light emission parameter including at least one of a light emission time, a light emission frequency, and a light emission amount according to a control signal, and generating a current pulse applied to a light emitting unit according to the determined light emission parameter; receiving light emitted by the light emitting unit to a light receiving unit to obtain a photocurrent; integrating the photocurrent to generate a voltage signal; comparing the voltage signal with a reference voltage to determine an output such that the period or high section length of the output signal changes according to the rate of change over time of the voltage signal; counting the repetition period or high section length of the output signal for a predetermined time to generate a digital value; and selecting at least one of a plurality of delay paths based on the digital value to finely adjust the pulse width of the current pulse. Claim 8 A computer-readable recording medium storing a computer program for executing the method according to paragraph 7 on a computer.

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