Signal adjustment circuit and imaging device

Abstract

The present invention discloses a signal adjustment circuit and an imaging device. The signal adjustment circuit comprises a photosensitive module, which is used for converting a light signal into an initial electric signal; an adjustment module, which is used for comparing the initial electric signal with a reference threshold value and adjusting the initial electric signal according to the comparison result until the adjusted electric signal is within the reference threshold value range; an analog-to-digital conversion module, which is used for converting the adjusted electric signal into a digital signal; and a processing module, which is used for restoring the digital signal to obtain the initial electric signal. The present invention adjusts the light signal by adding the adjustment module, ensures that the light signal is within the threshold range of the analog-to-digital conversion module before conversion and output, thereby effectively expanding the dynamic range of the analog-to-digital conversion module in a strong light environment and improving the application range of TOF.

Description

Technical Field

[0001] The present application relates to the field of TOF technology, and in particular to a signal adjustment circuit and an imaging device. Background Art

[0002] 3D Time of flight (TOF) technology provides 3D distance depth map by using CMOS (Complementary Metal Oxide Semiconductor) pixel array or CCD (charge coupled device) pixel array and active modulated light source technology. In this technology, each pixel of the array can measure the brightness of the corresponding target and the arrival time of the modulated light reflected back, so as to calculate the distance depth corresponding to that point. TOF methods include indirect time of flight (I-TOF) and direct time of flight (D-TOF). Whether based on I-TOF or D-TOF, it is necessary to receive reflected light for imaging.

[0003] TOF technology uses reflected light as the input light source of the sensor. The light is emitted by the transmitter. The farther the object is, the greater the attenuation of the reflected light. Therefore, for image sensors, such a passive signal source is relatively weak compared to noise, that is, the signal-to-noise ratio is relatively low. Ambient light accounts for the largest proportion of noise, especially when the ambient light is strong, the dynamic range of photosensitivity is very large, but the dynamic range of photosensitivity of existing analog-to-digital conversion circuits is limited and cannot meet application requirements. Summary of the invention

[0004] The object of the present invention is to provide a signal adjustment circuit and an imaging device, which can effectively solve the problem that the analog-to-digital conversion circuit cannot meet the application requirements in a strong light environment due to the limited dynamic range of photosensitivity.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An embodiment of the present application provides a signal adjustment circuit, including:

[0007] A photosensitive module, used for converting light signals into initial electrical signals;

[0008] An adjustment module, used for comparing the initial electrical signal with a reference threshold, and adjusting the initial electrical signal according to the comparison result until the adjusted electrical signal is within the reference threshold range;

[0009] An analog-to-digital conversion module, used for converting the adjusted electrical signal into a digital signal;

[0010] The processing module is used to restore the digital signal to obtain the initial electrical signal.

[0011] In the signal adjustment circuit of some embodiments, the adjustment module is specifically used to compare the initial electrical signal with the first reference signal, and when the initial electrical signal is greater than the first reference signal, adjust the initial electrical signal until the adjusted electrical signal is less than or equal to the first reference signal.

[0012] In the signal adjustment circuit of some embodiments, the adjustment module is further used to adjust the initial electrical signal when the initial electrical signal is smaller than the second reference signal until the adjusted electrical signal is greater than or equal to the second reference signal; wherein the first reference signal is greater than the second reference signal.

[0013] In some embodiments of the signal adjustment circuit, the adjustment module includes:

[0014] an attenuation unit, used for attenuating the initial electrical signal according to the current attenuation coefficient and then outputting the signal to the first comparison unit;

[0015] A first comparison unit is used to compare the attenuated electrical signal with a first reference signal, and when the attenuated electrical signal is less than or equal to the first reference signal, trigger the analog-to-digital conversion module to start, and output the attenuated electrical signal to the analog-to-digital conversion module; or when the attenuated electrical signal is greater than the first reference signal, output an adjustment signal to the attenuation unit;

[0016] The attenuation unit is also used to adjust the attenuation coefficient according to a preset step size based on the adjustment signal when the attenuated electrical signal is greater than the first reference signal, and to attenuate the initial electrical signal again according to the adjusted attenuation coefficient until the attenuated electrical signal is less than or equal to the first reference signal.

[0017] In some embodiments of the signal adjustment circuit, the adjustment module includes:

[0018] an attenuation unit, used for attenuating the initial electrical signal according to the current attenuation coefficient and then outputting the signal to the first comparison unit;

[0019] A first comparison unit is used to compare the attenuated electrical signal with the current first reference signal, and when the attenuated electrical signal is smaller than the current first reference signal, trigger the analog-to-digital conversion module to start, and output the attenuated electrical signal to the analog-to-digital conversion module; or when the attenuated electrical signal is larger than the current first reference signal, output an adjustment signal to the first adjustment unit;

[0020] A first regulating unit, configured to output a current reference voltage to the attenuation unit after regulating the first reference signal according to the regulating signal;

[0021] A first counter, used to trigger the attenuated signal to the attenuation unit and then count up by 1 when the attenuated electrical signal is greater than the current reference signal, or to output the count value when the attenuated electrical signal is less than the current first reference signal;

[0022] The attenuation unit is further used to, when the attenuated electrical signal is greater than the first reference signal, subtract the attenuation step length from the initial electrical signal according to the attenuation signal and output the result to the first comparison unit.

[0023] In some embodiments of the signal adjustment circuit, the adjustment module includes:

[0024] A charge release unit, used for releasing the charge according to the initial electrical signal;

[0025] A first comparison unit is used to compare the current released charge number of the charge release unit with the reference charge number, and when the current released charge number is less than the upper reference charge number, trigger the analog-to-digital conversion module to turn on, and output the current released charge number to the analog-to-digital conversion module; or when the current released charge number is greater than the reference charge number, turn off the charge release unit and trigger the first counter to count;

[0026] The first counter is used to count up by 1 when the current released charge number is greater than the reference charge number, and trigger the charge release unit to release the charge again; or output the count value when the current released charge number is less than the reference charge number.

[0027] In some embodiments of the signal adjustment circuit, the adjustment module further includes:

[0028] an amplifying unit, used for amplifying the initial electrical signal according to a current amplification factor and then outputting the amplified signal to the second comparing unit;

[0029] A second comparison unit is used to compare the amplified electrical signal with a second reference signal, and when the amplified electrical signal is greater than the second reference signal, trigger the analog-to-digital conversion module to start, and output the amplified electrical signal to the conversion module; or when the amplified electrical signal is less than the second reference signal, output an adjustment signal to the amplification unit;

[0030] The amplification unit is also used to adjust the amplification factor according to a preset step size according to the adjustment signal when the amplified electrical signal is smaller than the second reference signal, and to amplify the initial electrical signal again according to the adjusted amplification factor until the amplified electrical signal is larger than the second reference signal.

[0031] In some embodiments of the signal adjustment circuit, the adjustment module further includes:

[0032] an amplifying unit, used for amplifying the initial electrical signal according to a current amplification factor and then outputting the amplified signal to the second comparing unit;

[0033] A second comparison unit is used to compare the amplified electrical signal with the current second reference signal, and when the amplified electrical signal is greater than the current second reference signal, trigger the analog-to-digital conversion module to start, and output the amplified electrical signal to the analog-to-digital conversion module; or when the amplified electrical signal is less than the current second reference signal, output the adjustment signal to the second adjustment unit;

[0034] A second regulating unit, configured to output a current reference voltage to the amplifying unit after regulating the second reference signal according to the regulating signal;

[0035] A second counter, used to trigger the amplified signal to the amplifying unit and then count up by 1 when the amplified electrical signal is smaller than the current second reference signal, or to output a count value when the amplified electrical signal is larger than the current second reference signal;

[0036] The amplifying unit is further used to add the current second reference signal to the initial electrical signal according to the amplified signal and output the result to the second comparing unit when the amplified electrical signal is smaller than the second reference signal.

[0037] In some embodiments of the signal conditioning circuit, the attenuation unit includes a first switch, a second switch, a third switch, a first capacitor, a variable capacitor, and a first operational amplifier;

[0038] One end of the first switch is connected to the photosensitive module, the other end of the first switch is connected to one end of the second switch and one end of the first capacitor, the other end of the first capacitor, one end of the third switch and the first end of the variable capacitor are all connected to the inverting input of the first operational amplifier, the other end of the second switch is grounded, the non-inverting input of the first operational amplifier is grounded, the output of the operational amplifier is connected to the first comparison unit, the other end of the third switch and the second end of the variable capacitor are both connected to the output of the operational amplifier, and the third end of the variable capacitor is connected to the first comparison unit.

[0039] An embodiment of the present application further provides an imaging device, comprising the above-mentioned signal adjustment circuit.

[0040] Compared with the prior art, the present invention provides a signal adjustment circuit and an imaging device, which adjust the optical signal by adding an adjustment module to ensure that the optical signal is within the threshold range of the analog-to-digital conversion module before conversion and output, thereby effectively expanding the dynamic range of the analog-to-digital conversion module in a strong light environment and improving the application scope of TOF. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a structural block diagram of the signal adjustment circuit provided by the present invention.

[0042] Figure 2 This is a structural block diagram of a first embodiment of an adjustment module in a signal adjustment circuit provided by the present invention.

[0043] Figure 3 This is a working principle diagram of the first embodiment of the adjustment module in the signal adjustment circuit provided by the present invention.

[0044] Figure 4 This is a logic principle diagram of the first embodiment of the adjustment module in the signal adjustment circuit provided by the present invention.

[0045] Figure 5 This is a structural block diagram of a second embodiment of an adjustment module in a signal adjustment circuit provided by the present invention.

[0046] Figure 6 This is a working principle diagram of the second embodiment of the adjustment module in the signal adjustment circuit provided by the present invention.

[0047] Figure 7 This is a logic principle diagram of the second embodiment of the adjustment module in the signal adjustment circuit provided by the present invention.

[0048] Figure 8 This is a structural block diagram of a third embodiment of an adjustment module in a signal adjustment circuit provided by the present invention.

[0049] Fig. 9 This is a working flow chart of the third embodiment of the adjustment module in the signal adjustment circuit provided by the present invention.

[0050] Fig.10 This is a working principle diagram of the fourth embodiment of the signal adjustment circuit provided by the present invention.

[0051] Fig.11 This is a structural block diagram of a fourth embodiment of an adjustment module in a signal adjustment circuit provided by the present invention.

[0052] Fig.12 This is a working principle diagram of the fourth embodiment of the adjustment module in the signal adjustment circuit provided by the present invention.

[0053] Fig.13 This is a structural block diagram of a fifth embodiment of an adjustment module in a signal adjustment circuit provided by the present invention.

[0054] Fig.14 This is the working principle of the fifth embodiment of the adjustment module in the signal adjustment circuit provided by the present invention.

[0055] Fig.15 This is a logic principle diagram of a fifth embodiment of an adjustment module in a signal adjustment circuit provided by the present invention. DETAILED DESCRIPTION

[0056] In view of the deficiencies of the prior art, an object of the present invention is to provide a signal adjustment circuit and an imaging device, which can effectively solve the problem that the analog-to-digital conversion circuit cannot meet the application requirements in a strong light environment due to the limited dynamic range of photosensitivity.

[0057] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0058] See also Figure 1 The signal adjustment circuit provided by the present invention includes a photosensitive module 100, an adjustment module 200, an analog-to-digital conversion module 300 and a processing module 400. The photosensitive module 100 is connected to the adjustment module 200, the adjustment module 200 is connected to the analog-to-digital conversion module 300 and the processing module 400, and the analog-to-digital conversion module 300 is also connected to the processing module 400. The analog-to-digital conversion module 300 is connected to the photosensitive module 100; wherein, the photosensitive module 100 is used to convert the optical signal into an initial electrical signal, the adjustment module 200 is used to compare the initial electrical signal with a reference threshold, and adjust the initial electrical signal according to the comparison result until the adjusted electrical signal is within the reference threshold range; the analog-to-digital conversion module 300 is used to convert the adjusted electrical signal into a digital signal; the processing module 400 is used to restore the digital signal to obtain the initial electrical signal, and the initial electrical signal corresponds to the optical signal, thereby completing the imaging process.

[0059] The present invention can effectively expand the dynamic processing range of the analog-to-digital conversion module 300 by setting the adjustment module 200 to adjust the initial electrical signal before converting and outputting it, thereby improving the application range of TOF.

[0060] In a specific implementation, the adjustment module 200 is specifically used to compare the initial electrical signal with the first reference signal, and when the initial electrical signal is greater than the first reference signal, adjust the initial electrical signal until the adjusted electrical signal is less than or equal to the first reference signal.

[0061] In the present invention, the adjustment module 200 compares the received initial electrical signal with the first reference signal. It should be noted that, in this embodiment, the first reference signal is the upper limit value of the threshold range, i.e., the reference threshold, in the analog-to-digital conversion module 300. When the initial electrical signal is less than or equal to the first reference signal, i.e., the initial electrical signal received by the adjustment module 200 is not saturated and is within the threshold range of the analog-to-digital conversion module 300, then the adjustment module 200 does not need to adjust the initial electrical signal, and directly outputs the initial electrical signal to the analog-to-digital conversion module 300, and the analog-to-digital conversion module 300 directly converts the initial electrical signal into a digital signal and outputs it to the processing module 400, and the processing module 400 restores the digital signal to obtain the initial electrical signal. If the current ambient light intensity is too large, the initial electrical signal obtained by the photosensitive module 100 is greater than the first reference signal and exceeds the dynamic range of the analog-to-digital conversion module 300. Then, the adjustment module 200 sets the corresponding adjustment parameters to adjust the initial electrical signal until the adjusted electrical signal is less than or equal to the first reference signal. Then, the adjusted electrical signal is output to the analog-to-digital conversion module 300 for conversion into a digital signal, and the corresponding adjustment parameters are output to the processing module 400. The analog-to-digital conversion module 300 also outputs the obtained digital signal to the processing module 400, so that the processing module 400 reversely restores the actual electrical signal, i.e., the initial electrical signal, according to the adjustment parameters and the digital signal, and then obtains the corresponding image information. The present invention can effectively expand the dynamic range of the analog-to-digital conversion module 300 in a strong light environment by setting the adjustment module 200 to adjust the initial electrical signal before converting and outputting it, thereby improving the application range of TOF.

[0062] For specific implementation, please refer to Figure 2 In the first embodiment of the present invention, the adjustment module 200 includes an attenuation unit 210 and a first comparison unit 220. The attenuation unit 210 is connected to the photosensitive module 100 and the first comparison unit 220 respectively. The first comparison unit 220 is connected to the analog-to-digital conversion module 300. The processing module 400 is connected to the attenuation unit 210.

[0063] In specific implementation, the attenuation unit 210 is used to attenuate the initial electrical signal according to the current attenuation coefficient and then output it to the first comparison unit 220; the first comparison unit 220 is used to compare the attenuated electrical signal with the first reference signal, and when the attenuated electrical signal is less than or equal to the first reference signal, trigger the analog-to-digital conversion module 300 to start, and output the attenuated electrical signal to the analog-to-digital conversion module 300; when the first comparison unit 220 compares that the attenuated electrical signal is greater than the first reference signal, it outputs an adjustment signal to the attenuation unit 210. Then, when the attenuated electrical signal is greater than the first reference signal, the attenuation unit 210 will adjust the attenuation coefficient according to the preset step size according to the adjustment signal, and attenuate the initial electrical signal again according to the adjusted attenuation coefficient until the attenuated electrical signal is less than or equal to the first reference signal.

[0064] Please also read Figure 3In this embodiment, the first reference signal is a reference voltage. The photosensitive module 100 performs photoelectric conversion to convert the optical signal into an electrical signal and then outputs it to the attenuation unit 210. The attenuation unit 210 attenuates the initial electrical signal according to the attenuation coefficient and then outputs a voltage signal to the first comparison unit 220. The first comparison unit 220 compares the voltage signal with the reference voltage to determine whether it is saturated. If the voltage signal is less than the reference voltage, it indicates that the current optical signal is not saturated, then the analog-to-digital conversion module 300 is directly triggered to start, and the voltage signal is output to the analog-to-digital conversion module 300. The analog-to-digital conversion module 300 converts the voltage signal into a digital signal and outputs it to the processing module 400. At the same time, the attenuation unit 210 outputs the corresponding attenuation coefficient to the processing module 400, so as to facilitate the subsequent reverse deduction to obtain the actual electrical signal. If the voltage signal output by the attenuation unit 210 is greater than the reference voltage, it indicates that the current optical signal is saturated, and then an adjustment signal is output to the attenuation unit 210, so that the attenuation unit 210 adjusts the attenuation coefficient according to the preset step size according to the adjustment signal. For example, if the attenuation is 1 / 2 for the first time, it can be attenuated by 1 / 4 for the second time. Then the attenuation unit 210 attenuates the initial electrical signal again according to the adjusted attenuation coefficient. The first comparison unit 220 compares the voltage signal output by the attenuation unit 210 again to determine whether it is saturated. If the voltage signal is still greater than the reference voltage, the adjustment signal is output to the attenuation unit 210 again, and the attenuation coefficient is adjusted to attenuate the initial electrical signal again. This process is repeated until the voltage signal output by the attenuation unit 210 is less than the reference voltage. The first comparison unit 220 triggers the analog-to-digital conversion module 300 to start, converts the attenuated voltage and outputs it to the processing module 400, and the attenuation unit 210 outputs the attenuation coefficient of the last attenuation of the initial electrical signal to the processing module 400. Since the reference voltage in this embodiment is the upper limit value of the threshold range of the analog-to-digital conversion module 300, when in an environment with strong light, the optical signal is converted to within the threshold range of the analog-to-digital conversion module 300 through the adjustment module 200, and then the actual signal is restored by reverse calculation according to the attenuation coefficient during subsequent processing. The specific restoration process is to multiply the obtained digital signal by the attenuation coefficient to obtain the actual image data, thereby effectively expanding the dynamic range of the analog-to-digital conversion module 300 in a strong light environment and improving the application range of TOF.

[0065] Please also refer to Figure 4In this embodiment, the attenuation unit 210 includes a first switch Ph1, a second switch Ph2, a third switch Ph3, a first capacitor C1, a variable capacitor C0 and a first operational amplifier A1; one end of the first switch Ph1 is connected to the photosensitive module 100, the other end of the first switch Ph1 is connected to one end of the second switch Ph2 and one end of the first capacitor C1, the other end of the first capacitor C1, one end of the third switch Ph3 and the first end of the variable capacitor C0 are all connected to the inverting input end of the first operational amplifier A1, the other end of the second switch Ph2 is grounded, the non-inverting input end of the first operational amplifier A1 is grounded, the output end of the operational amplifier is connected to the first comparison unit 220, the other end of the third switch Ph3 and the second end of the variable capacitor C0 are both connected to the output end of the operational amplifier, and the third end of the variable capacitor C0 is connected to the first comparison unit 220; wherein, by adjusting the size of the variable capacitor C0, the attenuation coefficient in the attenuation unit 210 can be adjusted, so as to achieve multiple attenuation of the initial electrical signal, thereby ensuring that the optical signal is within the threshold range of the analog-to-digital conversion module 300.

[0066] Furthermore, in the present embodiment, the first comparison unit 220 includes a first comparator CM1, a non-inverting input terminal of the first comparator CM1 is connected to the dual output terminals of the first operational amplifier A1, an inverting input terminal of the first comparator CM1 is connected to the first input terminal, and an output terminal of the first comparator CM1 is respectively connected to the third terminal of the variable capacitor C0 and the analog-to-digital conversion module 300. In the present embodiment, the voltage signal output by the attenuation unit 210 is compared by setting the first comparator, so as to convert the optical signal after attenuating it to within the threshold range. The circuit setting structure is simple, thereby ensuring that the complexity of the analog-to-digital conversion module 300 is not increased.

[0067] For further information, see Figure 5 In the second embodiment of the present invention, the adjustment module 200 includes an attenuation unit 210, a first comparison unit 220, a first adjustment unit 230 and a first counter 240; the attenuation unit 210 is respectively connected to the photosensitive module 100, the first comparison unit 220 and the first counter 240, the first comparison unit 220 is connected to the first counter 240, and the first counter 240 is also connected to the processing module 400.

[0068] In specific implementation, the attenuation unit 210 is used to attenuate the initial electrical signal according to the current attenuation coefficient and then output it to the first comparison unit 220; the first comparison unit 220 is used to compare the attenuated electrical signal with the current first reference signal, and when the attenuated electrical signal is less than the current first reference signal, trigger the analog-to-digital conversion module 300 to turn on and output the attenuated electrical signal to the analog-to-digital conversion module 300; or when the attenuated electrical signal is greater than the current first reference signal, output the adjustment signal to the first adjustment unit 230; the first adjustment unit 230 is used to adjust the first reference signal according to the adjustment signal and then output the current reference voltage to the attenuation unit 210; the first counter 240 is used to trigger the attenuation signal to the attenuation unit 210 when the attenuated electrical signal is greater than the current first reference signal and then count up by 1, or output the count value when the attenuated electrical signal is less than the current first reference signal; the attenuation unit 210 is also used to, when the attenuated electrical signal is greater than the current first reference signal, subtract the attenuation step from the initial electrical signal according to the attenuation signal and then output it to the first comparison unit 220.

[0069] Please also read Figure 6In this embodiment, different from the first embodiment, the initial electrical signal is attenuated by changing the reference voltage, i.e., the upper limit value in the threshold range of the analog-to-digital conversion module 300. Specifically, the attenuation unit 210 attenuates the input initial electrical signal according to the initial attenuation coefficient and outputs a voltage signal to the first comparison unit 220. The first comparison unit 220 compares the voltage signal with the current reference voltage, i.e., the current upper limit value of the analog-to-digital conversion module 300. When the voltage signal is greater than the current reference voltage, an adjustment signal is output to the first adjustment unit 230, so that the first adjustment unit 230 adjusts the reference voltage and outputs the adjusted reference voltage to the attenuation unit 210. At the same time, the first counter 240 triggers the attenuation signal to the attenuation unit 210 and counts by 1. The attenuation unit 210 will subtract the attenuation step from the initial voltage signal according to the attenuation signal, and then output the attenuated voltage to the first comparison unit 220; the first comparison unit 220 will compare the voltage with the adjusted reference voltage, that is, the current reference voltage, and again determine whether it is greater than the current reference voltage. If so, the adjustment signal will be output to the first adjustment unit 230 again; the first adjustment unit 230 will adjust the reference voltage again according to the adjustment signal, and output the adjusted reference voltage to the attenuation unit 210; similarly, at this time, the first counter 240 will trigger the attenuation signal to the attenuation unit 210, and the count will increase by 1. Then the attenuation unit 210 will attenuate the initial electrical signal again by subtracting the attenuation step length according to the attenuation signal, until the first comparison unit 220 compares that the voltage signal output by the attenuation unit 210 is less than the current reference voltage, then the first comparison unit 220 directly triggers the start of the analog-to-digital conversion module 300, and the analog-to-digital conversion module 300 converts the current reference voltage, i.e., the current upper limit value, and outputs the digital signal to the processing module 400; and the first counter 240 will output the final calculated value to the processing module 400. The processing module 400 reversely restores the actual signal according to the count value and the digital signal, and the specific restoration process is that the processing module 400 adds the product of the count value and the attenuation step length to the obtained digital signal to obtain the initial electrical signal.

[0070] In this embodiment, by dynamically changing the upper limit value of the threshold range of the analog-to-digital conversion module 300, the initial electrical signal is attenuated by subtracting the attenuation step from the initial electrical signal, thereby ensuring that the optical signal is within the threshold range of the analog-to-digital conversion module 300, thereby effectively expanding the dynamic range of the analog-to-digital conversion module 300 in a strong light environment and improving the application range of TOF.

[0071] For further information, please also refer to Figure 7In this embodiment, the attenuation unit 210 includes a fourth switch Ph4, a fifth switch Ph5, a sixth switch Ph6, a second capacitor C2, a third capacitor C3 and a second operational amplifier A2; one end of the fourth switch Ph4 is connected to the photosensitive unit, the other end of the fourth switch Ph4 and one end of the fifth switch Ph5 are both connected to one end of the second capacitor C2, the other end of the second capacitor C2, one end of the sixth switch Ph6 and one end of the third capacitor C3 are all connected to the inverting input end of the second operational amplifier A2, the other end of the sixth switch Ph6 and the other end of the third capacitor C3 are both connected to the output end of the second operational amplifier A2, the non-inverting input end of the second operational amplifier A2 is grounded, the other end of the fifth switch Ph5 is connected to the first adjustment unit 230, and the output end of the second operational amplifier A2 is connected to the first comparison unit 220. In this embodiment, when the fifth switch Ph5 is turned on, the attenuation unit 210 receives the reference voltage output by the first adjustment unit 230, and uses the voltage as the current reference voltage to implement the process of attenuating the initial electrical signal.

[0072] Furthermore, in the present embodiment, the first adjustment unit 230 includes a first resistor R1, a second resistor R2 and a third operational amplifier A3; the first end of the first resistor R1 and one end of the second resistor R2 are both connected to the inverting input end of the third operational amplifier A3, the second end of the first resistor R1 is grounded, the third end of the first resistor R1 is connected to the first comparison unit 220, the other end of the second resistor R2 and the output end of the third operational amplifier A3 are connected to the attenuation unit 210, and the non-inverting input end of the third operational amplifier A3 is connected to the second input end; in the present embodiment, the second resistor R2 is an adjustable resistor, and the first adjustment unit 230 adjusts the resistance value of the adjustable resistor according to the adjustment signal, thereby realizing effective adjustment of the upper limit value of the threshold range in the analog-to-digital conversion module 300.

[0073] Further, in this embodiment, the first comparison unit 220 includes a second comparator CM2, the non-inverting input terminal of the second comparator CM2 is connected to the output terminal of the second operational amplifier A2, the inverting input terminal of the second comparator CM2 is connected to the first input terminal, and the output terminal of the second comparator CM2 is connected to the third terminal of the first resistor R1; when the attenuation unit 210 outputs a voltage signal to the second comparator CM2 after attenuating the initial electrical signal, the second comparator CM2 compares the voltage signal with the current reference voltage, and the current reference voltage corresponds to the upper limit value in the threshold range of the analog-to-digital conversion module 300. When the attenuated voltage signal is less than the current reference voltage, the second comparator CM2 directly triggers the analog-to-digital conversion module 300 to turn on, and outputs the attenuated voltage signal to the analog-to-digital conversion module 300 for analog-to-digital conversion. When the attenuated voltage signal is greater than the current reference voltage, the second comparator CM2 outputs an adjustment signal to the first adjustment unit 230, and the current reference voltage, i.e., the upper limit value of the threshold range in the analog-to-digital conversion module 300, is adjusted by the first adjustment unit 230, and the adjusted upper limit value is output by the first adjustment unit 230 to the attenuation unit 210, and the attenuation unit 210 uses the adjusted upper limit value as the current reference voltage to attenuate the initial electrical signal again and then outputs the voltage signal to the first comparison unit 220. The second comparator CM2 uses the adjusted upper limit value as the current reference voltage to compare with the voltage signal, and again determines the magnitude of the voltage signal and the current reference voltage. If the voltage signal is less than the current reference voltage, the analog-to-digital conversion module 300 is directly triggered to start working, and the threshold range does not need to be adjusted. If the voltage signal is greater than the current reference voltage, the adjustment signal needs to be continuously output to adjust the upper limit value of the threshold range, and the attenuation continues until the voltage signal output by the attenuation unit 210 is less than the current reference voltage, i.e., the voltage signal output by the attenuation unit 210 is within the threshold range. In this embodiment, a comparator is provided to compare the voltage signal output by the attenuation unit 210 so as to convert the optical signal after attenuating it to within a threshold range. The circuit configuration is simple, thereby ensuring that the complexity of the analog-to-digital conversion module 300 is not increased.

[0074] For further information, see Figure 8 In the third embodiment of the present invention, the adjustment module 200 includes a charge release unit 250, a first comparison unit 220 and a first counter 240; the charge release unit 250 is respectively connected to the photosensitive module 100, the first comparison unit 220 and the first counter 240, and the first comparison unit 220 is respectively connected to the first counter 240 and the analog-to-digital conversion module 300.

[0075] Specifically, the charge release unit 250 is used to release charges according to the initial electrical signal, and stops releasing when the first comparison unit 220 is working; the first comparison unit 220 is used to compare the current released charge number of the charge release unit 250 with the reference charge number, and when the current released charge number is less than the reference charge number, trigger the analog-to-digital conversion module 300 to turn on, and output the current released charge number to the analog-to-digital conversion module 300; or when the current released charge number is greater than the reference charge number, turn off the charge release unit 250 and trigger the first counter 240 to count; the first counter 240 is used to count plus 1 when the current released charge number is greater than the reference charge number, and trigger the charge release unit 250 to release the charge again; or output the count value when the current released charge number is less than the reference charge number.

[0076] Please also read Fig. 9 In this embodiment, the photosensitive module 100 corresponds to a photoelectric conversion unit, which converts the optical signal into an initial electrical signal and outputs it to the charge release unit 250. The charge release unit 250 gradually releases the charge of the initial electrical signal to the first comparison unit 220 until all the charges of the initial electrical signal are released. After each release of the charge release unit 250, the first comparison unit 220 compares the current released charge number with the reference charge number. If the current released charge number is less than the reference charge number, the first comparison unit 220 directly triggers the analog-to-digital conversion module 300 to start, and outputs the current released charge number to the analog-to-digital conversion module 300 for analog-to-digital conversion. If the current released charge number is greater than the reference charge number, the charge release unit 250 is closed and the first counter 240 is triggered to count. Correspondingly, the first counter 240 will count plus 1. When the first counter 240 counts plus 1, the charge release unit 250 will be triggered to start the next charge release. Similarly, the first comparison unit 220 will compare the current released charge number with the reference charge number again. When the current released charge number is less than the reference charge, the analog-to-digital conversion module 300 will be triggered to perform analog-to-digital conversion on the current released charge number. If the current released charge number is greater than the reference charge, the charge release unit 250 will be triggered to close, and the first counter 240 will be triggered to count plus 1. After the first counter 240 counts plus 1, the charge release unit 250 will be triggered to start the next charge release, and so on, until all the charges of the initial electrical signal are released. The first counter 240 will output the final count value to the processing module 400, and the processing module 400 will reversely deduce the actual signal, that is, the initial electrical signal, based on the count value and the digital signal output by the analog-to-digital conversion module 300, so as to obtain the corresponding optical signal for imaging.

[0077] In the present embodiment, for the photosensitive module 100 for charge transfer, the charge transfer timing is controlled. When the first comparison unit 220 and the first counter 240 are working, no charge transfer is performed and no signal is omitted. The charge number is reduced to a reasonable range before analog-to-digital conversion is performed. During subsequent processing, the actual signal is obtained by reverse deduction based on the count value and the digital signal. This can expand the dynamic range of the analog-to-digital conversion module 300 in a strong light environment and ensure that the design complexity of the analog-to-digital conversion module 300 is not increased.

[0078] Furthermore, in the fourth embodiment of the present invention, the adjustment module 200 is also used to adjust the initial electrical signal when the initial electrical signal is less than the second reference signal until the adjusted electrical signal is greater than or equal to the second reference signal; wherein the first reference signal is greater than the second reference signal. In this embodiment, the second reference signal corresponds to the lower limit value of the threshold range, i.e., the reference threshold value, in the analog-to-digital conversion module 300. When the initial electrical signal is less than the second reference signal, it indicates that the initial electrical signal is not within the threshold range of the analog-to-digital conversion module 300. At this time, the initial electrical signal is adjusted by the adjustment module 200 to ensure that the electrical signal input to the analog-to-digital conversion module 300 is converted within its threshold range.

[0079] See also Fig.10 That is to say, in this embodiment, when the adjustment module 200 receives the initial electrical signal, it will determine whether the initial electrical signal is greater than the threshold range or less than the threshold range. If it is greater than the threshold range, that is, the initial electrical signal is greater than the first reference signal (the upper limit of the threshold range), then the adjustment module 200 will attenuate the initial signal, which is the processing process in Embodiments 1, 2 or 3. If the initial electrical signal is less than the threshold range, that is, the initial electrical signal is less than the second reference voltage (the lower limit of the threshold range), then the adjustment module 200 will amplify it.

[0080] For more details, please refer to Fig.11In this embodiment, the adjustment module 200 also includes an amplification unit 260 and a second comparison unit 270. The amplification unit 260 is connected to the photosensitive module 100 and the second comparison unit 270 respectively, and the second comparison unit 270 is also connected to the analog-to-digital conversion module 300. Among them, the amplification unit 260 is used to amplify the initial electrical signal according to the current amplification factor and output it to the second comparison unit 270; the second comparison unit 270 is used to compare the amplified electrical signal with the second reference signal, and when the amplified electrical signal is greater than or equal to the second reference signal, trigger the analog-to-digital conversion module 300 to start, and output the amplified electrical signal to the conversion module; or when the amplified electrical signal is less than the second reference signal, output an adjustment signal to the amplification unit 260; the amplification unit 260 is also used to adjust the amplification factor according to a preset step size according to the adjustment signal when the amplified electrical signal is less than the second reference signal, and amplify the initial electrical signal again according to the adjusted amplification factor until the amplified electrical signal is greater than or equal to the second reference signal. Please refer to Fig.12In this embodiment, the second reference signal is a reference voltage. The photosensitive module 100 performs photoelectric conversion to convert the light signal into an electrical signal and then outputs it to the amplifying unit 260. The amplifying unit 260 amplifies the initial electrical signal according to the amplification factor and then outputs a voltage signal to the second comparing unit 270. The second comparing unit 270 compares the voltage signal with the reference voltage to determine whether it is less than the lower limit of the threshold range. If the voltage signal is greater than the second reference voltage, it indicates that the current electrical signal is within the threshold range, then the analog-to-digital conversion module 300 is directly triggered to start, and the voltage signal is output to the analog-to-digital conversion module 300. The analog-to-digital conversion module 300 converts the voltage signal into a digital signal and outputs it to the processing module 400. At the same time, the amplifying unit 260 outputs the corresponding amplification factor to the processing module 400, so as to facilitate the subsequent reverse deduction to obtain the actual electrical signal. If the voltage signal output by the amplifier unit 260 is less than the reference voltage, it indicates that the current electrical signal is not within the threshold range, and then the adjustment signal is output to the amplifier unit 260, so that the amplifier unit 260 adjusts the amplification factor according to the preset step size according to the adjustment signal. For example, if the amplification is 2 times for the first time, then it can be amplified 4 times for the second time. Then the amplifier unit 260 amplifies the initial electrical signal again according to the adjusted amplification factor, and the second comparison unit 270 compares the voltage signal output by the amplifier unit 260 again. If the comparison shows that the voltage signal is still less than the reference voltage, then the adjustment signal is output to the amplifier unit again. The first comparison unit 270 will trigger the analog-to-digital conversion module 300 to start, convert the amplified voltage and output it to the processing module 400, and the second comparison unit 270 will trigger the analog-to-digital conversion module 300 to start, and the amplified voltage will be converted and output to the processing module 400, and the amplification unit 260 will output the amplification factor of the last amplification of the initial electrical signal to the processing module 400, and the processing module 400 will restore the actual signal according to the digital signal and the amplification factor output by the analog-to-digital conversion module 300, and the specific restoration process is to divide the digital signal by the amplification factor. Because the reference voltage in this embodiment is the lower limit value of the threshold range of the analog-to-digital conversion module 300, when in an environment with low light intensity, the optical signal is changed to the threshold range of the analog-to-digital conversion module 300 by the adjustment module 200 for conversion, and the actual signal is subsequently restored according to the amplification factor during processing, thereby effectively expanding the dynamic range of the analog-to-digital conversion module 300 in a weak light environment and improving the application range of TOF.

[0081] It should be noted that the circuit structure of the adjustment module 200 in this embodiment is the same as that in the first embodiment, that is, the circuit structure of the amplifying unit 260 and the circuit structure of the second comparison unit 270 in this embodiment are the same as the circuit structure of the attenuation unit 210 and the first comparison unit 220 in the first embodiment. Therefore, the specific structure of the amplifying unit 260 and the second comparison unit 270 in this embodiment will not be repeated here.

[0082] For further information, see Fig.13 In the fifth embodiment of the present invention, the adjustment module 200 also includes an amplifying unit 260, a second comparing unit 270, a second regulating unit 280 and a second counter 290. The amplifying unit 260 is respectively connected to the second regulating unit 280, the second comparing unit 270 and the second counter 290. The second comparing unit 270 is also connected to the analog-to-digital conversion module 300 and the second counter 290. Among them, the amplification unit 260 is used to amplify the initial electrical signal according to the current amplification factor and output it to the second comparison unit 270; the second comparison unit 270 is used to compare the amplified electrical signal with the current second reference signal, and when the amplified electrical signal is greater than the current second reference signal, trigger the analog-to-digital conversion module 300 to start, and output the amplified electrical signal to the analog-to-digital conversion module 300; or when the amplified electrical signal is less than the current second reference signal, output the adjustment signal to the second adjustment unit 280; the second adjustment unit 280 is used to adjust the second reference signal according to the adjustment signal and output the current reference voltage to the amplification unit 260; the second counter 290 is used to trigger the amplification signal to the amplification unit 260 when the amplified electrical signal is less than the current second reference signal and then count up by 1, or output the count value when the amplified electrical signal is greater than the current second reference signal; the amplification unit 260 is also used to add the initial electrical signal to the current second reference signal according to the amplification signal and output it to the second comparison unit 270 when the amplified electrical signal is less than the second reference signal.

[0083] In specific implementation, the amplifier unit 260 is used to amplify the initial electrical signal according to the current amplification factor and then output it to the second comparison unit 270; the second comparison unit 270 is used to compare the amplified electrical signal with the current second reference signal, and when the amplified electrical signal is greater than the current second reference signal, trigger the analog-to-digital conversion module 300 to turn on and output the amplified electrical signal to the analog-to-digital conversion module 300; or when the amplified electrical signal is less than the current second reference signal, output the adjustment signal to the second adjustment unit 280; the second adjustment unit 280 is used to adjust the second reference signal according to the adjustment signal and then output the current reference voltage to the amplifier unit 260; the first counter 240 is used to trigger the amplification signal to the amplifier unit 260 when the amplified electrical signal is less than the current second reference signal and then count up by 1, or output the count value when the amplified electrical signal is greater than the current second reference signal; the amplifier unit 260 is also used to subtract the current second reference signal from the initial electrical signal according to the amplification signal and then output it to the second comparison unit 270 when the amplified electrical signal is greater than the current second reference signal.

[0084] Please also read Fig.14In this embodiment, unlike the fourth embodiment, the initial electrical signal is amplified by changing the reference voltage, i.e., the lower limit value in the threshold range of the analog-to-digital conversion module 300. Specifically, the amplifying unit 260 amplifies the input initial electrical signal according to the initial amplification factor and outputs a voltage signal to the second comparing unit 270. The second comparing unit 270 compares the voltage signal with the current reference voltage, i.e., the current lower limit value of the analog-to-digital conversion module 300. When the voltage signal is less than the current reference voltage, an adjustment signal is output to the second adjusting unit 280, so that the second adjusting unit 280 adjusts the reference voltage and outputs the adjusted reference voltage to the amplifying unit 260. At the same time, the first counter 240 triggers the amplification signal to the amplifying unit 260 and counts by 1. The amplifying unit 260 will add the input reference voltage, i.e., the current reference voltage, to the initial voltage signal according to the amplified signal. The current reference voltage corresponds to the lower limit value of the analog-to-digital conversion module 300, and then output the amplified voltage to the second comparing unit 270; the second comparing unit 270 compares the voltage with the adjusted reference voltage, i.e., the current reference voltage, and determines again whether it is greater than the current reference voltage. If so, the adjusting signal is output again to the second adjusting unit 280; the second adjusting unit 280 adjusts the reference voltage again according to the adjusting signal, and outputs the adjusted reference voltage to the amplifying unit 260; similarly, at this time, the first counter 240 will trigger the amplified signal to the amplifying unit 260, and the count will be increased by 1. Then the amplification unit 260 will increase the amplification step size of the initial electrical signal again according to the amplified signal to amplify it, until the second comparison unit 270 compares that the voltage signal output by the amplification unit 260 is greater than the current reference voltage, then the second comparison unit 270 directly triggers the start of the analog-to-digital conversion module 300, and the analog-to-digital conversion module 300 converts the current reference voltage, that is, the current lower limit value, and outputs the digital signal to the processing module 400; and the first counter 240 outputs the final calculated value to the processing module 400. The processing module 400 reversely restores the count value and the digital signal to obtain the actual signal, and the specific restoration process is to multiply the count value and the amplification step size into the digital signal output by the analog-to-digital conversion module 300, so as to obtain the initial electrical signal.

[0085] In this embodiment, by dynamically changing the lower limit value of the threshold range of the analog-to-digital conversion module 300, the initial electrical signal is amplified by adding the amplification step, ensuring that the optical signal is within the threshold range of the analog-to-digital conversion module 300, thereby effectively expanding the dynamic range of the analog-to-digital conversion module 300 in a low-light environment and improving the application scope of TOF.

[0086] Specifically, see Fig.15In this embodiment, the amplification unit 260 includes a seventh switch Ph7, an eighth switch Ph8, a ninth switch Ph9, a tenth switch Ph10, an eleventh switch Ph11, a fourth capacitor C4, a fifth capacitor C5 and a fourth operational amplifier A4; one end of the seventh switch Ph7 is grounded, the other end of the seventh switch Ph7 and one end of the eighth switch Ph8 are both connected to one end of the fifth capacitor C5, the other end of the fifth capacitor C5 is connected to one end of the ninth switch Ph9 and one end of the tenth switch Ph10, the other end of the ninth switch Ph9 is powered, the other end of the eighth switch Ph8 is connected to the second adjustment unit 280, the other end of the tenth switch Ph10, one end of the fourth capacitor C4 and one end of the eleventh switch Ph11 are all connected to the inverting input terminal of the fourth operational amplifier A4, the non-inverting input terminal of the fourth operational amplifier A4 is grounded, and the output terminal of the fourth operational amplifier A4, the other end of the eleventh switch Ph11 and the other end of the fourth capacitor C4 are all connected to the second comparing unit 270. In this embodiment, the second comparison unit 270 includes a third comparator CM3, a non-inverting input terminal of the third comparator CM3 is connected to the output terminal of the fourth operational amplifier A4, an inverting input terminal of the third comparator CM3 is connected to the first input terminal, and an output terminal of the third comparator CM3 is connected to the second adjustment unit 280. In this embodiment, the voltage signal output by the amplification unit 260 is compared by setting the third comparator CM3, so as to facilitate conversion after amplifying the optical signal to within the threshold range. The circuit setting structure is simple, thereby ensuring that the complexity of the circuit is not increased.

[0087] Among them, the second adjustment unit 280 includes a fifth operational amplifier A5, a third resistor R3 and a fourth resistor R4, the non-phase input terminal of the fifth operational amplifier A5 is connected to the second input terminal, the inverting input terminal of the fifth operational amplifier A5 is connected to one end of the fourth resistor R4 and the first end of the third resistor R3, the second end of the third resistor R3 is connected to the output end of the third comparator CM3, the third end of the third resistor R3 is grounded, and the other end of the fourth resistor R4 and the output end of the fifth operational amplifier A5 are both connected to the other end of the eighth resistor; in this embodiment, the third resistor R3 is an adjustable resistor, and the second adjustment unit 280 adjusts the resistance value of the adjustable resistor according to the adjustment signal, thereby realizing effective adjustment of the lower limit value of the threshold range in the analog-to-digital conversion module 300.

[0088] Furthermore, the present invention also provides an imaging device, which includes the above-mentioned signal adjustment circuit and a processing module, wherein the processing module is used to output an initial electrical signal according to the digital signal obtained by the signal adjustment circuit and the adjustment parameter, so as to obtain corresponding image information. In this embodiment, the adjustment parameter may be an attenuation coefficient or a count value of a counter. In this embodiment, the adjustment parameter may be an amplification coefficient or a count value of a counter. A proportional coefficient greater than 1 is an amplification coefficient, and a proportional coefficient less than 1 is an attenuation coefficient. It should be noted that the adjustment module embodiment of the present invention may only compare the upper limit value in the threshold range for attenuation processing, that is, the adjustment module only includes an attenuation part (such as the structure of the adjustment module in the first embodiment, the second embodiment or the third embodiment), or may compare the lower limit value in the threshold range for amplification processing, that is, the adjustment module only includes an amplification part (such as the part of the adjustment module in the fourth embodiment and the fifth embodiment). Of course, the adjustment module may include an amplification part and an attenuation part at the same time, so as to realize both the amplification function and the attenuation function, which is not limited by the present invention. The processing module reversely deduces the actual electrical signal according to the attenuation coefficient and the digital signal or the count value and the digital signal, so as to obtain the image information corresponding to the optical signal. The present invention expands the dynamic range that can be quantified by the analog-to-digital conversion module in a strong light environment by designing the structure of the analog-to-digital conversion module in the signal adjustment circuit, so that when the ambient light is very strong, the dynamic range will be very wide, thereby increasing the scope of application. Since the signal adjustment circuit is described in detail above, it will not be repeated here.

[0089] In summary, the present invention provides a signal adjustment circuit and an imaging device, wherein the signal adjustment circuit includes a photosensitive module, which is used to convert a light signal into an initial electrical signal; an adjustment module, which is used to compare the initial electrical signal with a reference threshold, and adjust the initial electrical signal according to the comparison result until the adjusted electrical signal is within the reference threshold range; an analog-to-digital conversion module, which is used to convert the adjusted electrical signal into a digital signal; and a processing module, which is used to restore the digital signal to obtain the initial electrical signal. The present invention adjusts the light signal by adding an adjustment module to ensure that the light signal is within the threshold range of the analog-to-digital conversion module before being converted and output, thereby effectively expanding the dynamic range of the analog-to-digital conversion module in a strong light environment and improving the application range of TOF.

[0090] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the claims attached to the present invention.

Claims

1. A signal adjustment circuit, characterized in that: include: A photosensitive module, used for converting light signals into initial electrical signals; an adjustment module, configured to compare the initial electrical signal with a reference threshold, and adjust the initial electrical signal according to the comparison result until the adjusted electrical signal is within the reference threshold range; An analog-to-digital conversion module, used for converting the adjusted electrical signal into a digital signal; A processing module, used for restoring the digital signal to obtain the initial electrical signal; The adjustment module comprises: an attenuation unit, configured to attenuate the initial electrical signal according to a current attenuation coefficient and then output the signal to the first comparison unit; A first comparison unit is used to compare the attenuated electrical signal with a first reference signal, and when the attenuated electrical signal is smaller than the first reference signal, trigger the analog-to-digital conversion module to start, and output the attenuated electrical signal to the analog-to-digital conversion module; or when the attenuated electrical signal is larger than the first reference signal, output an adjustment signal to the first adjustment unit; A first regulating unit, configured to output a current reference voltage to the attenuation unit after regulating the first reference signal according to the regulating signal; A first counter, used to trigger the attenuation signal to the attenuation unit and then count up by 1 when the attenuated electrical signal is greater than the current reference signal, or to output the count value when the attenuated electrical signal is less than the current first reference signal; The attenuation unit is further configured to, when the attenuated electrical signal is greater than the first reference signal, subtract the attenuation step length from the initial electrical signal according to the attenuation signal and output the resultant signal to the first comparison unit.

2. The signal conditioning circuit according to claim 1, characterized in that: The adjustment module is specifically used to adjust the initial electrical signal when the initial electrical signal is smaller than a second reference signal until the adjusted electrical signal is greater than or equal to the second reference signal; wherein the first reference signal is greater than the second reference signal.

3. The signal conditioning circuit according to claim 2, characterized in that: The adjustment module also includes: an amplifying unit, configured to amplify the initial electrical signal according to a current amplification factor and then output the amplified signal to a second comparing unit; A second comparison unit is used to compare the amplified electrical signal with a second reference signal, and when the amplified electrical signal is greater than the second reference signal, trigger the analog-to-digital conversion module to start, and output the amplified electrical signal to the conversion module; or when the amplified electrical signal is less than the second reference signal, output an adjustment signal to the amplification unit; The amplification unit is also used to adjust the amplification factor according to a preset step size based on the adjustment signal when the amplified electrical signal is smaller than the second reference signal, and to amplify the initial electrical signal again according to the adjusted amplification factor until the amplified electrical signal is larger than the second reference signal.

4. The signal conditioning circuit according to claim 2, characterized in that: The adjustment module also includes: an amplifying unit, configured to amplify the initial electrical signal according to a current amplification factor and then output the amplified signal to a second comparing unit; A second comparison unit is used to compare the amplified electrical signal with the current second reference signal, and when the amplified electrical signal is greater than the current second reference signal, trigger the analog-to-digital conversion module to start, and output the amplified electrical signal to the analog-to-digital conversion module; or when the amplified electrical signal is less than the current second reference signal, output an adjustment signal to the second adjustment unit; A second regulating unit, configured to output a current reference voltage to the amplifying unit after regulating the second reference signal according to the regulating signal; A second counter, used to trigger the amplified signal to the amplifying unit and then count up by 1 when the amplified electrical signal is smaller than the current second reference signal, or to output a count value when the amplified electrical signal is larger than the current second reference signal; The amplifying unit is further configured to add the current second reference signal to the initial electrical signal according to the amplified signal and output the result to the second comparing unit when the amplified electrical signal is smaller than the second reference signal.

5. The signal conditioning circuit according to claim 1, characterized in that: The attenuation unit includes a first switch, a second switch, a third switch, a first capacitor, a variable capacitor and a first operational amplifier; One end of the first switch is connected to the photosensitive module, the other end of the first switch is connected to one end of the second switch and one end of the first capacitor, the other end of the first capacitor, one end of the third switch and the first end of the variable capacitor are all connected to the inverting input of the first operational amplifier, the other end of the second switch is grounded, the non-inverting input of the first operational amplifier is grounded, the output of the operational amplifier is connected to the first comparing unit, the other end of the third switch and the second end of the variable capacitor are both connected to the output of the operational amplifier, and the third end of the variable capacitor is connected to the first comparing unit.

6. An imaging device, characterized in that: The invention comprises the signal adjustment circuit as described in any one of claims 1 to 5.

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