Signal detection circuit, integrated circuit and electronic device

Abstract

Embodiments of the present application provide a signal detection circuit, an integrated circuit, and an electronic device. The signal detection circuit includes: a conversion circuit for receiving an external background current and outputting a first voltage conversion signal based on the background current; a logic control circuit connected to the conversion circuit and configured to output a control signal based on the first voltage conversion signal, wherein the control signal includes N digital bits; a correction circuit connected to the logic control circuit and the conversion circuit, respectively, and configured to output a compensation current to the conversion circuit based on the control signal, so that the conversion circuit outputs a second voltage conversion signal based on the background current and the compensation current, wherein the voltage value of the second voltage conversion signal is less than or equal to a preset value; and the logic control circuit is further configured to adjust the code values of some of the N digital bits based on the first voltage conversion signal to adjust the current value of the compensation current. The signal detection circuit provided by the embodiments of the present application can effectively improve the compensation effect in scenarios where the ambient light changes rapidly.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a signal detection circuit, an integrated circuit, and an electronic device. Background Art

[0002] In recent years, with the continuous development of science and technology, the application of semiconductor-related products has become more and more extensive. As an important component of them, photosensitive devices have always received a high degree of attention in the market. In some application scenarios of photosensitive devices (such as pulse meters and smart bracelets), it is usually necessary to compensate for the ambient light in which the photosensitive device is located so that the target light can be accurately detected. In the prior art, in order to eliminate the influence of ambient light on the detection of target light by the photosensitive device, the background current generated by the ambient light is usually compensated. However, in situations where the ambient light changes frequently, the compensation value may deviate greatly from the actual background current, resulting in poor compensation effect. Summary of the Invention

[0003] In view of the above problems, embodiments of the present application provide a signal detection circuit, an integrated circuit, and an electronic device to solve the above technical problems.

[0004] This application specifically adopts the following technical solutions:

[0005] A signal detection circuit includes a conversion circuit, a logic control circuit, and a correction circuit; the conversion circuit is used to receive an external background current and output a first voltage conversion signal according to the background current; the logic control circuit is connected to the conversion circuit and is used to output a control signal according to the first voltage conversion signal, the control signal including N digital bits, where N is a positive integer greater than 0; the correction circuit is respectively connected to the logic control circuit and the conversion circuit, and is used to output a compensation current to the conversion circuit according to the control signal, so that the conversion circuit outputs a second voltage conversion signal according to the background current and the compensation current, and the voltage value of the second voltage conversion signal is less than or equal to a preset value; the logic control circuit is also used to adjust the code value of the first to Mth digital bits from low to high in the N digital bits according to the first voltage conversion signal, so as to adjust the current value of the compensation current, where M is a positive integer greater than 0 and M is less than N.

[0006] In some embodiments, the signal detection circuit also includes a comparison circuit, which is used to compare the first voltage conversion signal with a preset voltage threshold signal; the logic control circuit is also used to adjust the code values of the first to Mth digital bits from low to high among the N digital bits according to the first voltage conversion signal when the first voltage conversion signal is greater than the voltage threshold signal.

[0007] In some embodiments, the logic control circuit is further used to output a control signal according to the first voltage conversion signal within a first correction cycle; and to adjust the code values of the first to Mth digital bits from low to high in the N digital bits according to the first voltage conversion signal within a second correction cycle, wherein each two adjacent second correction cycles are separated by a preset number of first correction cycles.

[0008] In some embodiments, the logic control circuit is also used to determine the maximum value of multiple first voltage conversion signals within a preset number of first correction cycles, and adjust the code values of the first to Mth digital bits from low to high among the N digital bits according to the maximum value within the second correction cycle.

[0009] In some embodiments, the logic control circuit is also used to determine the increment of the first voltage conversion signal within the second correction period. If the current value corresponding to the increment is greater than the maximum value of the current adjustment range corresponding to the first to M-th digital bits from low to high in the N digital bits, the code values of the 1+P to M+P-th digital bits from low to high in the N digital bits are adjusted according to the first voltage conversion signal, where P is a positive integer greater than 0, and M+P is less than or equal to N.

[0010] In some embodiments, the correction circuit is a digital-to-analog converter.

[0011] In some embodiments, the conversion circuit includes a transconductance amplifier, an input terminal of the transconductance amplifier is connected to the digital-to-analog converter, and an output terminal of the transconductance amplifier is connected to the comparison circuit.

[0012] In some embodiments, the voltage threshold signal includes a first threshold signal and a second threshold signal, the output end of the transconductance amplifier includes a first output end and a second output end, and the comparison circuit includes a first comparator and a second comparator; the first input end of the first comparator is used to access the first threshold signal, the second input end of the first comparator is connected to the first output end of the transconductance amplifier, and the output end of the first comparator is connected to the logic control circuit; the first input end of the second comparator is used to access the second threshold signal, the second input end of the second comparator is connected to the second output end of the transconductance amplifier, and the output end of the second comparator is connected to the logic control circuit; the logic control circuit is also used to determine whether to adjust the code values of the first to Mth digital bits from low to high in the N digital bits according to the first voltage conversion signal based on the comparison results of the first comparator and the second comparator.

[0013] An embodiment of the present application further provides an integrated circuit, comprising any of the signal detection circuits described above.

[0014] An embodiment of the present application further provides an electronic device, comprising a device body and an integrated circuit such as any one of the above items provided in the device body.

[0015] The signal detection circuit provided in the embodiment of the present application includes a conversion circuit, a logic control circuit and a correction circuit; the conversion circuit is used to receive an external background current and output a first voltage conversion signal according to the background current; the logic control circuit is connected to the conversion circuit and is used to output a control signal according to the first voltage conversion signal, and the control signal includes N digital bits, where N is a positive integer greater than 0; the correction circuit is respectively connected to the logic control circuit and the conversion circuit, and is used to output a compensation current to the conversion circuit according to the control signal, so that the conversion circuit outputs a second voltage conversion signal according to the background current and the compensation current, and the voltage value of the second voltage conversion signal is less than or equal to a preset value; the logic control circuit is also used to adjust the code value of the first to Mth digital bits from low to high in the N digital bits according to the first voltage conversion signal to adjust the current value of the compensation current, where M is a positive integer greater than 0, and M is less than N. The signal detection circuit in the present application adjusts the current value of the compensation current by adjusting the code values of the first to M-th digital bits from low to high in N digital bits through a first voltage conversion signal. During the compensation current adjustment process, the voltage value of the second voltage conversion signal always remains less than or equal to the preset value, so that when the ambient light changes rapidly and causes the background current to change, the background current can be adaptively compensated in real time according to the change in the background current, thereby effectively improving the compensation effect in the scenario of rapid changes in ambient light.

[0016] These and other aspects of the present application will become more readily apparent from the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A module block diagram of a signal detection circuit provided in an embodiment of the present application is shown.

[0019] Figure 2 Another module block diagram of the signal detection circuit provided in an embodiment of the present application is shown.

[0020] Figure 3 A circuit diagram of a signal detection circuit provided in an embodiment of the present application is shown.

[0021] Figure 4 A schematic diagram of the correction period and the measurement period provided in an embodiment of the present application is shown.

[0022] Figure 5A schematic diagram of a first correction period and a second correction period provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0023] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0024] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0025] In recent years, with the continuous development of science and technology, the application of semiconductor-related products has become increasingly widespread. As an important component of this, photosensitive devices have always received high attention in the market. In some application scenarios of photosensitive devices (such as pulse monitors and smart bracelets), it is often necessary to compensate for the ambient light in which the photosensitive device is located so that the target light can be accurately detected. In the existing technology, in order to eliminate the influence of ambient light on the detection of target light by the photosensitive device, the background current generated by the ambient light is usually compensated. However, in situations where the ambient light changes frequently, there may be a significant deviation between the compensation value and the actual background current, resulting in poor compensation effect. For example, in pulse wave measurement, to eliminate the photodiode (PD) deviation current caused by ambient light, a digital-to-analog converter (DAC) is usually used to adjust and offset the background current generated by the ambient light. Specifically, during the power-on calibration process, the DAC current output range is scanned to make the output of the trans-impedance amplifier (TIA) close to zero. When the ambient light changes rapidly, the background current generated by the ambient light changes accordingly, making it impossible for the DAC current to accurately compensate for the background current.

[0026] Furthermore, during pulse wave measurement, the DAC current needs to be recalibrated at regular intervals to prevent TIA saturation. Currently, TIA saturation is determined using an ADC (Analog to Digital Converter). Rapid changes in ambient light can cause saturation during the ADC's measurement cycle. In this case, some ADC code values of the pulse wave signal must be discarded, resulting in a loss of pulse wave signal continuity.

[0027] In order to solve the above technical problems, the inventors have proposed, after long-term research, a signal detection circuit, an integrated circuit and an electronic device in the embodiments of the present application. The signal detection circuit includes a conversion circuit, a logic control circuit and a correction circuit; the conversion circuit is used to receive an external background current and output a first voltage conversion signal according to the background current; the logic control circuit is connected to the conversion circuit and is used to output a control signal according to the first voltage conversion signal, and the control signal includes N digital bits, where N is a positive integer greater than 0; the correction circuit is respectively connected to the logic control circuit and the conversion circuit, and is used to output a compensation current to the conversion circuit according to the control signal, so that the conversion circuit outputs a second voltage conversion signal according to the background current and the compensation current, and the voltage value of the second voltage conversion signal is less than or equal to a preset value; the logic control circuit is also used to adjust the code values of the first to Mth digital bits from low to high in the N digital bits according to the first voltage conversion signal to adjust the current value of the compensation current, where M is a positive integer greater than 0, and M is less than N. The signal detection circuit in the present application adjusts the current value of the compensation current by adjusting the code value of the first to Mth digital bits from the lowest to the highest of N digital bits through a first voltage conversion signal. During the compensation current adjustment process, the voltage value of the second voltage conversion signal always remains less than or equal to a preset value. This allows the compensation current to be dynamically corrected when the ambient light changes rapidly, causing changes in the background current. Furthermore, the background current is adaptively compensated in real time based on the changes in the background current, effectively improving the compensation effect in scenarios with rapidly changing ambient light. Furthermore, because the compensation current output by the first correction circuit can be dynamically corrected when the ambient light changes rapidly, it is ensured that the conversion circuit will not saturate during the sampling process, eliminating the need to discard ADC code values, thereby improving signal continuity.

[0028] like Figure 1 As shown, Figure 1The following is a block diagram of a signal detection circuit 100 provided in an embodiment of the present application. The signal detection circuit 100 includes a conversion circuit 110, a logic control circuit 120, and a correction circuit 130. The conversion circuit 110 is configured to receive an external background current; the input of the logic control circuit 120 is connected to the output of the conversion circuit 110, and the output of the logic control circuit 120 is connected to the input of the correction circuit 130; and the output of the correction circuit 130 is connected to the input of the conversion circuit 110.

[0029] Typically, a photoelectric sensor detects target light emitted by a light-emitting diode (LED) and reflected by the subject's skin, converting the target light signal into an electrical signal to obtain the subject's pulse wave signal. In actual detection, the presence of ambient light can affect the accuracy of target light conversion, thereby affecting the measurement accuracy of the pulse wave signal. In this embodiment, background current is generated by ambient light, which is also known as the deviation current caused by ambient light. Specifically, when the LED is off, the photoelectric sensor detects ambient light and converts the ambient light signal into background current.

[0030] The conversion circuit 110 is configured to receive the background current and output a first voltage conversion signal based on the background current. This first voltage conversion signal may represent the amount of deviation caused by ambient light. The logic control circuit 120 is configured to output a control signal based on the first voltage conversion signal. The correction circuit 130 is configured to output a compensation current to the conversion circuit 110 based on the control signal. This compensation current is used to ensure that the voltage value of the second voltage conversion signal output by the conversion circuit 110 based on the background current and the compensation current is less than or equal to a preset value. The preset value can be understood as the maximum allowable deviation. In other words, the compensation current is used to reduce the background current so that the output voltage of the conversion circuit 110 is within the allowable deviation range. In this embodiment, the preset value may be zero. When the preset value is zero, the compensation current can completely offset the background current, thereby completely eliminating the deviation caused by ambient light. In some embodiments, the preset value may be non-zero. When the preset value is non-zero, the compensation current can partially offset the background current, thereby reducing the deviation caused by ambient light to within the allowable deviation range.

[0031] In this embodiment, the control signal output by the logic control circuit 120 is a digital signal including N digital bits, where N is a positive integer greater than 0. For example, the control signal may be "000001100100." Furthermore, the logic control circuit 120 is further configured to adjust the code values of the first to Mth digital bits, from the lowest to the highest bit, of the N digital bits according to the first voltage conversion signal, to adjust the current value of the compensation current.

[0032] When ambient light changes rapidly, the magnitude of the background current also changes accordingly. At this point, the voltage value of the first voltage-converted signal output by the conversion circuit 110 based on the background current also changes accordingly. In this embodiment, when the voltage value of the first voltage-converted signal changes, the logic control circuit 120 dynamically adjusts the code values of the first through Mth digits of the N digital bits of the control signal, from the lowest to the highest, based on the change in the first voltage-converted signal. This dynamically adjusts the current value of the compensation current when ambient light changes rapidly, where M is a positive integer greater than 0 and less than N.

[0033] Specifically, when the ambient light increases, the background current increases, and the first voltage conversion signal output by the conversion circuit 110 also increases accordingly. At this time, the logic control circuit 120 can increase the code value of the first to M-th digital bits from low to high in the N digital bits of the control signal, so that the compensation current output by the correction circuit 130 increases; when the ambient light decreases, the background current decreases, and the first voltage conversion signal output by the conversion circuit 110 also decreases accordingly. At this time, the logic control circuit 120 can decrease the code value of the first to M-th digital bits from low to high in the N digital bits of the control signal, so that the compensation current output by the correction circuit 130 decreases.

[0034] As an example, assuming N=12, M=4, and the initial value of the control signal is "000001100100." When the ambient light increases, the logic control circuit 120 may increase the code value of the last four bits of the control signal, for example, adjusting the control signal to "000001101100." When the ambient light decreases, the logic control circuit 120 may decrease the code value of the last four bits of the control signal, for example, adjusting the control signal to "000001100010."

[0035] It should be noted that when the code values of the first to Mth digital bits from low to high in the N digital bits of the dynamically adjusted control signal are adjusted, the voltage value of the second voltage conversion signal output by the conversion circuit 110 based on the background current and the dynamically adjusted compensation current is always less than or equal to the preset value.

[0036] Therefore, when the ambient light changes rapidly, the dynamically adjusted compensation current in the embodiment of the present application offsets the changing background current, so that the deviation caused by the ambient light is always within the allowable deviation range, thereby effectively improving the compensation effect in the scenario where the ambient light changes rapidly.

[0037] In addition, in the process of dynamically adjusting the compensation current, the adjustment time is associated with the number of bits of the control signal. The more bits the control signal has, the longer it takes to adjust the compensation current. In an embodiment of the present application, when dynamically adjusting the compensation current, only the code values of the first to Mth digital bits from low to high in the N digital bits of the control signal are adjusted. At this time, the number of bits of the control signal adjusted is less than the original number of bits of the control signal, that is, only M digital bits need to be adjusted without adjusting N digital bits. Therefore, each adjustment of the compensation current only takes a short time, thereby enabling the compensation current to be adjusted quickly when the ambient light changes rapidly, ensuring that the conversion circuit 110 will not be saturated during the sampling process, thereby eliminating the need to discard the ADC code value and improving the continuity of the signal.

[0038] Furthermore, if Figure 2 As shown, the signal detection circuit 100 further includes a comparison circuit 140, which is connected to the conversion circuit 110 and the logic control circuit 120, respectively, and is configured to compare the first voltage conversion signal with a preset voltage threshold signal. In this embodiment, the logic control circuit 120 is further configured to adjust the code values of the first to Mth digital bits of the N digital bits, from the lowest to the highest bit, according to the first voltage conversion signal when the first voltage conversion signal is greater than the voltage threshold signal.

[0039] In this embodiment, the voltage threshold signal can represent the maximum value allowed by the first voltage conversion signal. When the first voltage conversion signal is greater than the voltage threshold signal, it indicates that the first voltage conversion signal exceeds the allowable deviation range, that is, the change in ambient light exceeds the allowable range. When the first voltage conversion signal is less than or equal to the voltage threshold signal, it indicates that the first voltage conversion signal is within the allowable deviation range, that is, the change in ambient light does not exceed the allowable range. Therefore, in this embodiment, when the change in ambient light exceeds the allowable range, the logic control circuit 120 adjusts the code value of the first to Mth digital bits of the N digital bits of the control signal from the lowest to the highest bit according to the first voltage conversion signal. When the change in ambient light does not exceed the allowable range, there is no need to adjust the code value of the control signal, thereby saving circuit power consumption.

[0040] As an example, Figure 3As shown, the conversion circuit 110 can be a trans-impedance amplifier (TIA). The input of the conversion circuit 110 can be connected to the external photosensor 10, and the conversion circuit 110 includes a first output terminal and a second output terminal. The voltage threshold signal includes a first voltage threshold signal and a second voltage threshold signal. The comparison circuit 140 includes a first comparator A1 and a second comparator A2. The first input terminal of the first comparator A1 is preset with the first threshold signal, the second input terminal of the first comparator A1 is connected to the first output terminal of the conversion circuit 110, and the output terminal of the first comparator is connected to the logic control circuit 120. The first input terminal of the second comparator A2 is preset with the second threshold signal, the second input terminal of the second comparator A2 is connected to the second output terminal of the conversion circuit 110, and the output terminal of the second comparator is connected to the logic control circuit 120. The logic control circuit 120 can determine whether to adjust the code values of the first to Mth digital bits of the N digital bits from the lowest to the highest bit according to the first voltage conversion signal based on the comparison results between the first comparator A1 and the second comparator A2. The correction circuit 130 is a digital-to-analog converter, and specifically may be a current-type digital-to-analog converter.

[0041] In the pulse wave signal measurement, there are correction period and measurement period. Figure 4 As shown, the calibration cycle and the measurement cycle can be performed alternately. The calibration cycle is used to compensate for ambient light, and the calibration cycle is used to measure the pulse wave signal based on the target light emitted by the LED. It is worth noting that during the calibration cycle, the LED is off, and the voltage value of the second voltage conversion signal output by the conversion circuit 110 based on the background current and the compensation current is less than or equal to a preset value. During the measurement cycle, the LED is on, and the current value of the compensation current output by the calibration circuit remains unchanged. Because the compensation current can reduce the background current generated by ambient light, the influence of ambient light can be eliminated during the measurement of the pulse wave signal.

[0042] like Figure 4 and Figure 5 As shown, in the embodiment of the present application, the correction period includes a first correction period and a second correction period. During the first correction period, the conversion circuit 110 outputs a first voltage conversion signal based on the background current. The first voltage conversion signal can be directly output to the logic control circuit 120 after ADC conversion. The logic control circuit 120 then outputs a control signal to the correction circuit 130 based on the first voltage conversion signal. The correction circuit 130 outputs a compensation current based on the control signal, so that the voltage value of the second voltage conversion signal output by the conversion circuit 110 based on the background current and the compensation current is less than or equal to a preset value.

[0043] During the second correction cycle, the logic control circuit 120 adjusts the code values of the first to Mth digital bits from low to high among the N digital bits in the control signal according to the first voltage conversion signal, and the correction circuit 130 outputs a compensation current according to the adjusted control signal, so that the voltage value of the second voltage conversion signal output by the conversion circuit 110 according to the background current and the compensation current is always less than or equal to the preset value.

[0044] Furthermore, a preset number of first calibration cycles may be present between each two adjacent second calibration cycles. That is, a second calibration cycle may be performed after each preset number of first calibration cycles. In this embodiment, the second calibration cycle may be performed immediately after the preset number of first calibration cycles have completed. For example, three first calibration cycles may be present between two adjacent second calibration cycles. Since the calibration cycles and measurement cycles are performed alternately, the order of the first and second calibration cycles during pulse wave signal measurement may be: first calibration cycle, measurement cycle, first calibration cycle, measurement cycle, first calibration cycle, and second calibration cycle.

[0045] During the second correction cycle, the logic control circuit 120 fine-tunes the code values of some digital bits in the control signal. In this embodiment, by fine-tuning the code values of some digital bits in the control signal every preset number of first correction cycles, circuit power consumption can be saved and resource consumption time can be reduced, thereby further effectively coping with compensation in scenarios where ambient light changes rapidly.

[0046] Furthermore, during the second correction cycle, the logic control circuit 120 is also used to determine the maximum value of multiple first voltage conversion signals within a preset number of first correction cycles, and adjust the code values of the first to Mth digital bits from low to high in the N digital bits according to the maximum value of the multiple first voltage conversion signals during the second correction cycle.

[0047] Because a second calibration cycle is performed after each preset number of first calibration cycles, the logic control circuit 120 can determine multiple first voltage conversion signals corresponding to the preset number of first calibration cycles. The logic control circuit 120 compares the multiple first voltage conversion signals and determines the maximum value among the multiple first voltage conversion signals. This maximum value among the multiple first voltage conversion signals can be used to represent the maximum change in ambient light during the preset number of first calibration cycles. If the maximum value among the multiple first voltage conversion signals is greater than the voltage threshold signal, the logic control circuit 120 adjusts the code values of the first through Mth digital bits of the N digital bits, from the lowest to the highest, according to the maximum value of the multiple first voltage conversion signals during the second calibration cycle. Specifically, the first threshold signal and the second threshold signal are a pair of differential signals. When the maximum value of the first voltage conversion signal is within the threshold window of the first threshold signal and the second threshold signal, it indicates that the maximum value of the first voltage conversion signal is within the allowable deviation range, that is, the maximum change of the ambient light is within the allowable variation range. When the maximum value of the first voltage conversion signal is outside the threshold window of the first threshold signal and the second threshold signal, it indicates that the maximum value of the first voltage conversion signal exceeds the allowable deviation range, that is, the maximum change of the ambient light exceeds the allowable variation range. At this time, the logic circuit adjusts the code value of the first to Mth digital bits of the N digital bits in the control signal from the lowest to the highest bit according to the maximum value of the first voltage conversion signal. In this embodiment, the maximum values of multiple first voltage conversion signals are used as the estimated value of the adjustment control signal, so that the accuracy of the compensation is guaranteed during the dynamic compensation process of the changing background current.

[0048] In some embodiments, after the correction circuit 130 outputs the compensation current for the first time within the second correction period, the second voltage conversion signal output by the conversion circuit 110 can be sequentially compared by the comparison circuit 140 to ensure that the voltage value of the second voltage conversion signal is less than or equal to a preset value. Specifically, the first comparator A1 and the second comparator A2 compare the second voltage conversion signal. If the second voltage conversion signal is within the threshold window between the first threshold signal and the second threshold signal, it indicates that the second voltage conversion signal is less than or equal to the preset value, indicating that the compensation circuit output by the correction circuit 130 has reduced the background current to within an allowable range. If the second voltage conversion signal is outside the threshold window between the first threshold signal and the second threshold signal, the logic control circuit 120 again adjusts the code value of some digital bits in the control signal according to the second voltage conversion signal to further adjust the current value of the compensation current output by the correction circuit 130. Then, the first comparator A1 and the second comparator A2 again compare the second voltage conversion signal output by the conversion circuit 110 according to the background current and the compensation current, so that the voltage value of the second voltage conversion signal sequentially approaches less than or equal to the preset value. It should be noted that the second voltage conversion signal represents the voltage signal output by conversion circuit 110 under the compensation of the compensation current. During the successive comparison process, the voltage signal output by conversion circuit 110 based on the background current and the compensation current is collectively referred to as the second voltage conversion signal. In this embodiment, by performing successive comparisons on the second voltage conversion signal output by conversion circuit 110, the voltage value of the second voltage conversion signal is ensured to be less than or equal to a preset value, thereby improving the accuracy of background current compensation.

[0049] In addition, the logic control circuit 120 is also used to determine the increment of the first voltage conversion signal within the second calibration period. If the current value corresponding to the increment is greater than the maximum value of the current adjustment range corresponding to the first to M-th digital bits from the low bit to the high bit in the N digital bits, the code values of the 1+P-th to M+P-th digital bits from the low bit to the high bit in the N digital bits are adjusted according to the first voltage conversion signal, where P is a positive integer greater than 0, and M+P is less than or equal to N.

[0050] Specifically, during the second calibration period, the logic control circuit 120 is further configured to determine the increment of the maximum value among the multiple first voltage conversion signals relative to the voltage value corresponding to the current control signal. This increment is also referred to as the voltage offset of the maximum value among the multiple first voltage conversion signals, which can also represent the change in ambient light. Furthermore, the increment of the first voltage conversion signal represents the value to be adjusted for the control signal. The logic control circuit 120 converts the increment of the first voltage conversion signal into a current value and adjusts the code values of the first through Mth digital bits of the N digital bits of the control signal, from the lowest to the highest bit, based on this current value.

[0051] It is worth noting that in this embodiment, the correction circuit 130 is a DAC, and N is the number of bits of the DAC. Taking a 12-bit DAC as an example, the control signal output by the logic control circuit 120 is a 12-bit binary code.

[0052] Furthermore, the first to M-th digital bits in the control signal correspond to a current adjustment range. For example, assuming that M is 4 and the minimum step size of the adjustment current corresponding to the control signal is 1A, the adjustment range corresponding to the first to fourth digital bits in the 12-bit control signal is 1 to 15A. When the current value corresponding to the increment of the first voltage conversion signal is greater than the maximum value of the current adjustment range corresponding to the first to M-th digital bits from low to high in the N digital bits of the control signal, the current value corresponding to the increment cannot be represented by the first to M-th digital bits. In this embodiment, the logic control circuit 120 can adjust the code value of the 1+P to M+P-th digital bits from low to high in the N digital bits according to the first voltage conversion signal, which is equivalent to changing the minimum step size of the adjustment current corresponding to the control signal in the second correction period, thereby expanding the current adjustment range.

[0053] As an example, taking a 12-bit digital-to-analog converter as an example, the control signal is a 12-bit binary code. Assuming that M is 4, and the minimum step size of the initial adjustment current corresponding to the control signal in the second correction cycle is 1A, the initial current adjustment range of the control signal is 1 to 15A; when the current value corresponding to the increment of the first voltage conversion signal is greater than 15A, for example, 20A, the logic control circuit 120 can represent the increment of the first voltage conversion signal by adjusting the code value of the 2nd to 5th digital bits from low to high in the control signal. At this time, the minimum step size of the adjustment current corresponding to the control signal in the second correction cycle is 2A, and the current adjustment range of the control signal is extended to 2 to 31A.

[0054] It can be seen that the signal detection circuit 100 provided in the embodiment of the present application compensates for the background current within the first correction period, and adjusts the code value of some digital bits in the control signal when the increment of the first voltage conversion signal caused by the rapid change of ambient light is greater than the voltage threshold signal within the second correction period, so as to adaptively compensate for the changing background current, thereby effectively improving the compensation effect in the scenario of rapid change of ambient light, and ensuring that the conversion circuit 110 will not be saturated during the sampling process, so that there is no need to discard the ADC code value, thereby improving the continuity of the signal.

[0055] As one approach, the increment of the first voltage conversion signal may be determined by the following equation (1):

[0056]

[0057] Among them, V OSis the increment of the first voltage conversion signal; FS is the reference voltage of the analog-to-digital converter; ADC max is the maximum value of multiple first voltage conversion signals; N is the number of bits of the analog-to-digital converter.

[0058] Furthermore, the current value corresponding to the increment of the first voltage conversion signal, that is, the current value of the compensation current, can be determined by the following formula (2):

[0059]

[0060] Among them, I OS is the current value corresponding to the increment of the first voltage conversion signal; R F is the transimpedance value of the transconductance amplifier.

[0061] As a method, the voltage value of the voltage threshold signal can be determined by the following formula (3):

[0062] V th =VCM±2*I LSB *R F (3)

[0063] Among them, V th is the voltage value of the voltage threshold signal; VCM is the common mode voltage of the transconductance amplifier; I LSB is the minimum step size of the regulating current corresponding to the control signal.

[0064] The signal detection circuit provided in the embodiment of the present application includes a conversion circuit, a logic control circuit and a correction circuit; the conversion circuit is used to receive an external background current and output a first voltage conversion signal according to the background current; the logic control circuit is connected to the conversion circuit and is used to output a control signal according to the first voltage conversion signal, and the control signal includes N digital bits, where N is a positive integer greater than 0; the correction circuit is respectively connected to the logic control circuit and the conversion circuit, and is used to output a compensation current to the conversion circuit according to the control signal, so that the conversion circuit outputs a second voltage conversion signal according to the background current and the compensation current, and the voltage value of the second voltage conversion signal is less than or equal to a preset value; the logic control circuit is also used to adjust the code value of the first to Mth digital bits from low to high in the N digital bits according to the first voltage conversion signal to adjust the current value of the compensation current, where M is a positive integer greater than 0, and M is less than N. The signal detection circuit in the present application adjusts the current value of the compensation current by adjusting the code values of the first to M-th digital bits from low to high in N digital bits through a first voltage conversion signal. During the compensation current adjustment process, the voltage value of the second voltage conversion signal always remains less than or equal to the preset value, so that when the ambient light changes rapidly and causes the background current to change, the background current can be adaptively compensated in real time according to the change in the background current, thereby effectively improving the compensation effect in the scenario of rapid changes in ambient light.

[0065] An embodiment of the present application further provides an integrated circuit, comprising the above-mentioned signal detection circuit.

[0066] The integrated circuit provided in the embodiment of the present application includes a conversion circuit, a logic control circuit and a correction circuit; the conversion circuit is used to receive an external background current and output a first voltage conversion signal according to the background current; the logic control circuit is connected to the conversion circuit and is used to output a control signal according to the first voltage conversion signal, and the control signal includes N digital bits, where N is a positive integer greater than 0; the correction circuit is respectively connected to the logic control circuit and the conversion circuit, and is used to output a compensation current to the conversion circuit according to the control signal, so that the conversion circuit outputs a second voltage conversion signal according to the background current and the compensation current, and the voltage value of the second voltage conversion signal is less than or equal to a preset value; the logic control circuit is also used to adjust the code value of the first to Mth digital bits from low to high in the N digital bits according to the first voltage conversion signal to adjust the current value of the compensation current, where M is a positive integer greater than 0, and M is less than N. The signal detection circuit in the present application adjusts the current value of the compensation current by adjusting the code values of the first to M-th digital bits from low to high in N digital bits through a first voltage conversion signal. During the compensation current adjustment process, the voltage value of the second voltage conversion signal always remains less than or equal to the preset value, so that when the ambient light changes rapidly and causes the background current to change, the background current can be adaptively compensated in real time according to the change in the background current, thereby effectively improving the compensation effect in the scenario of rapid changes in ambient light.

[0067] An embodiment of the present application further provides an electronic device, comprising a device body and the above-mentioned integrated circuit provided in the device body.

[0068] In this embodiment, electronic devices include but are not limited to smart bracelets, smart watches, steering wheels, electronic scales, and electrocardiogram detection devices.

[0069] The electronic device provided in an embodiment of the present application includes a conversion circuit, a logic control circuit and a correction circuit; the conversion circuit is used to receive an external background current and output a first voltage conversion signal according to the background current; the logic control circuit is connected to the conversion circuit and is used to output a control signal according to the first voltage conversion signal, and the control signal includes N digital bits, where N is a positive integer greater than 0; the correction circuit is respectively connected to the logic control circuit and the conversion circuit, and is used to output a compensation current to the conversion circuit according to the control signal, so that the conversion circuit outputs a second voltage conversion signal according to the background current and the compensation current, and the voltage value of the second voltage conversion signal is less than or equal to a preset value; the logic control circuit is also used to adjust the code value of the first to Mth digital bits from low to high in the N digital bits according to the first voltage conversion signal to adjust the current value of the compensation current, where M is a positive integer greater than 0, and M is less than N. The signal detection circuit in the present application adjusts the current value of the compensation current by adjusting the code values of the first to M-th digital bits from low to high in N digital bits through a first voltage conversion signal. During the compensation current adjustment process, the voltage value of the second voltage conversion signal always remains less than or equal to the preset value, so that when the ambient light changes rapidly and causes the background current to change, the background current can be adaptively compensated in real time according to the change in the background current, thereby effectively improving the compensation effect in the scenario of rapid changes in ambient light.

[0070] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present application. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A signal detection circuit, characterized in that: The signal detection circuit includes: a conversion circuit, configured to receive an external background current and output a first voltage conversion signal according to the background current; a logic control circuit connected to the conversion circuit and configured to output a control signal according to the first voltage conversion signal, wherein the control signal includes N digital bits, where N is a positive integer greater than 0; and a correction circuit, connected to the logic control circuit and the conversion circuit, respectively, and configured to output a compensation current to the conversion circuit according to the control signal, so that the conversion circuit outputs a second voltage conversion signal according to the background current and the compensation current, wherein the voltage value of the second voltage conversion signal is less than or equal to a preset value; the logic control circuit is further configured to increase the code value of the first to M-th digits from the low bit to the high bit of the N digits according to the first voltage conversion signal when the voltage value of the first voltage conversion signal increases, so as to increase the current value of the compensation current; and decrease the code value of the first to M-th digits from the low bit to the high bit of the N digits according to the first voltage conversion signal when the voltage value of the first voltage conversion signal decreases, so as to decrease the current value of the compensation current, wherein M is a positive integer greater than 0 and M is less than N; The logic control circuit is also used to output a control signal according to the first voltage conversion signal within a first correction cycle; and to adjust the code values of the first to M-th digital bits from low to high in the N digital bits according to the first voltage conversion signal within a second correction cycle, wherein each two adjacent second correction cycles are separated by a preset number of first correction cycles.

2. The signal detection circuit according to claim 1, wherein: The signal detection circuit further includes a comparison circuit, wherein the comparison circuit is configured to compare the first voltage conversion signal with a preset voltage threshold signal; The logic control circuit is further configured to adjust the code values of the first to Mth digital bits from low to high among the N digital bits according to the first voltage conversion signal when the first voltage conversion signal is greater than the voltage threshold signal.

3. The signal detection circuit according to claim 1, wherein: The logic control circuit is also used to determine the maximum value of multiple first voltage conversion signals within the preset number of first correction cycles, and adjust the code values of the first to Mth digital bits from low to high in the N digital bits according to the maximum value within the second correction cycle.

4. The signal detection circuit according to claim 1, wherein: The logic control circuit is further used to determine an increment of the first voltage conversion signal within the second correction period. If the current value corresponding to the increment is greater than the maximum value of the current adjustment range corresponding to the first to M-th digital bits from low to high in the N digital bits, the code values of the 1+P to M+P-th digital bits from low to high in the N digital bits are adjusted according to the first voltage conversion signal, where P is a positive integer greater than 0, and M+P is less than or equal to N.

5. The signal detection circuit according to any one of claims 2 to 4, wherein: The correction circuit is a digital-to-analog converter.

6. The signal detection circuit according to claim 5, wherein: The conversion circuit includes a transimpedance amplifier, an input end of the transimpedance amplifier is connected to the digital-to-analog converter, and an output end of the transimpedance amplifier is connected to a comparison circuit.

7. The signal detection circuit according to claim 6, wherein: The voltage threshold signal includes a first threshold signal and a second threshold signal, the output end of the transimpedance amplifier includes a first output end and a second output end, and the comparison circuit includes: a first comparator, wherein a first input terminal of the first comparator is used to receive the first threshold signal, a second input terminal of the first comparator is connected to a first output terminal of the transimpedance amplifier, and an output terminal of the first comparator is connected to the logic control circuit; and a second comparator, wherein a first input terminal of the second comparator is used to receive the second threshold signal, a second input terminal of the second comparator is connected to the second output terminal of the transimpedance amplifier, and an output terminal of the second comparator is connected to the logic control circuit; The logic control circuit is further configured to determine whether to adjust the code values of the first to Mth digital bits from low to high among the N digital bits according to the first voltage conversion signal based on the comparison results of the first comparator and the second comparator.

8. An integrated circuit, characterized in that: The device comprises the signal detection circuit according to any one of claims 1 to 7.

9. An electronic device, characterized in that: The device comprises a device body and the integrated circuit according to claim 8 provided in the device body.

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