The present disclosure relates to fields of semiconductor devices, integrated circuits and image sensing technology, and in particular, to a complementary phototransistor pixel unit capable of simultaneously calculating positive and negative weight values, a complementary phototransistor sensing and computing array structure adapted for high parallel vector-matrix multiplication and an operation method thereof, and a high parallel convolution implementation method adapted for in-sensor computing applications.
The traditional sensing and computing architecture generally consists of three parts: a sensing unit, a storage medium, and a computing core, which are interconnected through the bus. With the development of Internet of Things and big data, the amount of redundant data transmission between the sensing unit, the storage medium, and the computing core is increasing greatly, which severely limits hardware computing efficiency and increasing system power consumption.
In-sensor computing aims to achieve the fusion of sensing and computing functions through the devices and circuits co-optimization. This approach reduces data movement, lowers latency and power consumption, thereby improves system energy efficiency, making it an important technical pathway for edge sensing and computing. Currently, array structures composed of novel photo-sensitive devices are used to perform vector-matrix multiplication in conjunction with peripheral circuits, representing an important implementation form of in-sensor computing.
However, existing solutions face two main problems. Firstly, implementing positive and negative weights requires the design of different readout and control circuits, increasing the complexity of the array structure and operation methods. Secondly, to meet the requirements of reusing the operational matrix, the array interconnection structure and timing operations are highly complex, resulting in low computational parallelism.
In view of the above, the present disclosure proposes a complementary phototransistor pixel unit capable of simultaneously calculating positive and negative weight values, a complementary phototransistor sensing and computing array structure adapted for high parallel vector-matrix multiplication and an operation method thereof, and a high parallel convolution implementation method adapted for in-senor computing, so as to simplify the complexity of array structures and operation methods, improve the operational parallelism, and meet the requirement of reusing the operational matrix.
According to one aspect of embodiments of the present disclosure, there is provided a complementary phototransistor pixel unit capable of simultaneously calculating positive and negative weight values, where the complementary phototransistor pixel unit includes: a first photoelectric field effect transistor, where the first photoelectric field effect transistor is a photoelectric field effect transistor based on an ultra-thin body and buried oxide layer (UTBB); and a second photoelectric field effect transistor, where the second photoelectric field effect transistor is a photoelectric field effect transistor based on an ultra-thin body and buried oxide layer, and a type of the second photoelectric field effect transistor is different from a type of the first photoelectric field effect transistor, where each of the first photoelectric field effect transistor and the second photoelectric field effect transistor is a four-terminal device and has a gate electrode G, a source electrode S, a drain electrode D, and a well base electrode B, and the source electrode S or the drain electrode D of the first photoelectric field effect transistor is connected to the source electrode S or the drain electrode D of the second photoelectric field effect transistor.
In above-mentioned solutions, each of the first photoelectric field effect transistor and the second photoelectric field effect transistor includes: a doped well, and a UTBB field effect transistor formed on the doped well, where a doping type of the doped well is n-type or p-type, and the UTBB field effect transistor is an NMOS transistor or a PMOS transistor.
In above-mentioned solutions, for the first photoelectric field effect transistor and the second photoelectric field effect transistor, when the doping types of the doping wells of the first photoelectric field effect transistor and the second photoelectric field effect transistor are the same, the types of the UTBB field effect transistors of the first photoelectric field effect transistor and the second photoelectric field effect transistor are different, and when the doping types of the doping wells of the first photoelectric field effect transistor and the second photoelectric field effect transistor are different, the types of the UTBB field effect transistors of the first photoelectric field effect transistor and the second photoelectric field effect transistor are the same.
In above-mentioned solutions, a type of the first photoelectric field effect transistor is N-p (NMOS on p-type well), a type of the second photoelectric field effect transistor is N-n (NMOS on n-type well), and the source electrode S of the first photoelectric field effect transistor is connected to the source electrode S of the second photoelectric field effect transistor to form a common source electrode, denoted as IOUT.
In above-mentioned solutions, the complementary phototransistor pixel unit utilizes complementary photoelectric characteristics of the first photoelectric field effect transistor and the second photoelectric field effect transistor to input a negative weight into an exposed first photoelectric field effect transistor to complete operation, and input a positive weight into an exposed second photoelectric field effect transistor to complete operation, thereby allowing positive and negative weight operations to be compatible within one pixel unit.
In above-mentioned solutions, the complementary phototransistor pixel unit is capable of performing exposure, readout, and reset functions in operation, including: during exposure, a collection and conversion of an optical signal in the pixel unit is implemented by controlling a flip of a voltage of the well base electrode; during readout, the device is turned on or off by controlling a flip of a voltage of the gate electrode, a weight value input is completed by controlling a flip of a voltage of the drain electrode, an analog operation is completed inside the pixel unit, and a result is represented by a common source current; and during reset, a reset function of the pixel unit is completed by controlling a level signal of each port to return to zero, so as to prepare for a next exposure.
In above-mentioned solutions, a type of the first photoelectric field effect transistor is P-p (PMOS on p-type well), a type of the second photoelectric field effect transistor is P-n (PMOS on n-type well), and the drain electrode D of the first photoelectric field effect transistor is connected to the drain electrode D of the second photoelectric field effect transistor to form a common drain electrode, denoted as IOUT.
In above-mentioned solutions, the complementary phototransistor pixel unit utilizes complementary photoelectric characteristics of the first photoelectric field effect transistor and the second photoelectric field effect transistor to input a positive weight into an exposed first photoelectric field effect transistor to complete operation, and input a negative weight into an exposed second photoelectric field effect transistor to complete operation, thereby allowing positive and negative weight operations to be compatible within one pixel unit.
In above-mentioned solutions, the complementary phototransistor pixel unit is capable of performing exposure, readout, and reset functions in operation, including: during exposure, a collection and conversion of an optical signal in the pixel unit is implemented by controlling a flip of a voltage of the well base electrode; during readout, the device is turned on or off by controlling a flip of a voltage of the gate electrode, a weight value input is completed by controlling a flip of a voltage of the source electrode, an analog operation is completed inside the pixel unit, and a result is represented by a common drain current; and during reset, a reset function of the pixel unit is completed by controlling a level signal of each port to return to zero, so as to prepare for a next exposure.
In above-mentioned solutions, a type of the first photoelectric field effect transistor is N-p (NMOS on p-type well), a type of the second photoelectric field effect transistor is P-p (PMOS on a p-type well), and the source electrode S of the first photoelectric field effect transistor is connected to the drain electrode D of the second photoelectric field effect transistor to form a common output, denoted as IOUT.
In above-mentioned solutions, the complementary phototransistor pixel unit utilizes complementary photoelectric characteristics of the first photoelectric field effect transistor and the second photoelectric field effect transistor to input a negative weight into an exposed first photoelectric field effect transistor to complete operation, and input a positive weight into an exposed second photoelectric field effect transistor to complete operation, thereby allowing positive and negative weight operations to be compatible within one pixel unit.
In above-mentioned solutions, the complementary phototransistor pixel unit is capable of performing exposure, readout, and reset functions in operation, including: during exposure, a collection and conversion of an optical signal in the pixel unit is implemented by controlling a flip of a voltage of the well base electrode; during readout, the device is turned on or off by controlling a flip of a voltage of the gate electrode, a weight value input is completed by controlling a flip of a voltage of the drain electrode of the first photoelectric field effect transistor or a flip of a voltage of the source electrode of the second photoelectric field effect transistor, an analog operation is completed inside the pixel unit, and a result is represented by a common output current; and during reset, a reset function of the pixel unit is completed by controlling a level signal of each port to return to zero, so as to prepare for a next exposure.
In above-mentioned solutions, a type of the first photoelectric field effect transistor is N-n (NMOS on n-type well), a type of the second photoelectric field effect transistor is P-n (PMOS on n-type well), and the source electrode S of the first photoelectric field effect transistor is connected to the drain electrode D of the second photoelectric field effect transistor to form a common output, denoted as IOUT.
In above-mentioned solutions, the complementary phototransistor pixel unit utilizes complementary photoelectric characteristics of the first photoelectric field effect transistor and the second photoelectric field effect transistor to input a positive weight into an exposed first photoelectric field effect transistor to complete operation, input a negative weight into an exposed second photoelectric field effect transistor to complete operation, thereby allowing positive and negative weight operations to be compatible within one pixel unit.
In above-mentioned solutions, the complementary phototransistor pixel unit is capable of performing exposure, readout, and reset functions in operation, including: during exposure, a collection and conversion of an optical signal in the pixel unit is implemented by controlling a flip of a voltage of the well base electrode; during readout, the device is turned on or off by controlling a flip of a voltage of the gate electrode, a weight value input is completed by controlling a flip of a voltage of the drain electrode of the first photoelectric field effect transistor or a flip of a voltage of the source electrode of the second photoelectric field effect transistor, an analog operation is completed inside the pixel unit, and a result is represented by a common output current; and during reset, a reset function of the pixel unit is completed by controlling a level signal of each port to return to zero, so as to prepare for a next exposure.
According to another aspect of embodiments of the present disclosure, there provides a complementary phototransistor sensing and computing array structure adapted for high parallel vector-matrix multiplication, including: a plurality of complementary phototransistor pixel units, where the plurality of complementary phototransistor pixel units are arranged in an array structure.
In above-mentioned solutions, in order to implement row gating and weight value input functions, the connection relationship of a plurality of complementary phototransistor pixel units located in a same row of the complementary phototransistor sensing and computing array structure is as follows: The VBn ends of the plurality of complementary phototransistor pixel units located in the same row are all connected to a first exposure enabling control line EN+, and VBp ends of the plurality of complementary phototransistor pixel units located in the same row are all connected to a second exposure enabling control line EN−; VGn ends of the plurality of complementary phototransistor pixel units located in the same row are all connected to a first word line WL+, and VGp ends of the plurality of complementary phototransistor pixel units located in the same row are all connected to a second word line WL−. Additionally, the VDn ends of the plurality of complementary phototransistor pixel units located in the same row are all connected to a first bit line BL+, and VDp ends of the plurality of complementary phototransistor pixel units located in the same row are all connected to a second bit line BL−.
In above-mentioned solutions, a connection relationship of a plurality of complementary phototransistor pixel units located in a same column of the complementary phototransistor sensing and computing array structure is as follows to implement the current collection along column direction: IOUT ends of the plurality of complementary phototransistor pixel units located in the same column are all connected to a source line SL.
According to another aspect of embodiments of the present disclosure, there is further provided a method of operating the complementary phototransistor sensing and computing array structure, where the method includes: during parallel vector-matrix operation, flipping levels of a first exposure enabling control line EN+, a second exposure enabling control line EN−, a first word line WL+, and a second word line WL− of a specific row to implement exposure and selection of pixel units of the specific rows, inputting a weight value into the specific row through the bit line, and completing an analog operation inside each pixel unit, where operation results are represented by the source line current of each column.
In above-mentioned solutions, the method further includes: during the exposure period, flipping a level of a second exposure enabling control line EN− or a level of a first exposure enabling control line EN+ of the specific row to implement exposure to the pixel units of the specific row.
In above-mentioned solutions, during the exposure period, for positive weights, the level of the first exposure enabling control line EN+ is controlled to flip; and for negative weights, the level of the second exposure enabling control line EN− is controlled to flip.
In above-mentioned solutions, the method further includes: during the readout period, flipping the level of the second word line WL− or the first word line WL+ of the specific row to implement selection of the pixel units in the specific row; and controlling the level of the second bit line BL− or the first bit line BL+ of the specific row to flip to implement weight input; and during the period, collecting the current in source line SL of each column, so that an operation result is read out.
In above-mentioned solutions, during the readout period, when implementing the selection of the pixel units in the row, for positive weights, the level of the first word line WL+ is controlled to flip; for negative weights, the level of the second word line WL− is controlled to flip. During the readout period, when implementing weight input, for positive weights, the level of the first bit line BL+ is controlled to flip; for negative weights, the level of the second bit line BL− is controlled to flip.
In above-mentioned solutions, the method further includes: during the reset period, resetting levels of the first exposure enabling control line EN+, the second exposure enabling control line EN−, the first word line WL+, the second word line WL−, the first bit line BL+ and the second bit line BL−, and returning array state to the initial state.
According to another aspect of embodiments of the present disclosure, a high parallel convolution operation method for the complementary phototransistor sensing and computing array structure is provided. The method includes the following steps: during the readout period and the reset period, under the readout clock signal, the first word line WL+ or the second word line WL− is selectively activated based on the positive or negative values in the first column vector of the queue, and controlling a weight value of the vector to be input into the array through the first bit line BL+ or the second bit line BL− of 1 to k rows, outputting results of analog operations completed in the array in parallel through the source line SL of each column, and selecting effective data columns SLk to SLn to store in a register; controlling the second column vector of the queue to be input into the array to complete operation under a next readout clock signal, and selecting effective data columns SLk-1 to SLn-1 to store in the register; repeating the above process under the control of a readout clock until the last column vector of the queue is input into the array to complete operation, and selecting effective data columns SL1 to SLn-k to store in the register, and correspondingly adding effective data of each column vector operation by an addition circuit for operation results of the whole queue, so as to obtain 1×(n-k) row vector which is the first row of output matrix; and then controlling the selected row of the array to move downwards row by row, repeating the above process, sequentially inputting k column vectors of the queue into the array for operation, correspondingly adding effective data of each column vector operation by the addition circuit, sequentially obtaining the second row to the (n-k)th row of the output matrix, and finally obtaining a (n-k)×(n-k) output matrix.
In above-mentioned solutions, the method further includes: after completing the above process, resetting signals of each control line and waiting for a next operation process.
In above-mentioned solutions, the method adopts a one-exposure multi-reading mode when the convolution operation is performed on the array, so that the second exposure enabling control line EN− and the first exposure enabling control line EN+ of a specific row are exposed simultaneously during exposure period to adapt to the readout of positive and negative weight values during the readout period.
In above-mentioned solutions, for a case that the convolution step size is not 1, the method adjusts the selection and storage of operation result of the source line SL when a convolution operation is performed on the array.
In above-mentioned solutions, the method further includes: during a preprocessing period, dividing a k×k convolution kernel into k column vectors, and sequentially arranging the k column vectors from right to left, where a rightmost vector of the convolution kernel is the first vector in a queue, and k is a natural number.
In above-mentioned solutions, the method further includes: during the exposure period, for a m×n input matrix, exposing m rows of the m×n input matrix by the first exposure enabling control line EN+ or the second exposure enabling control line EN to complete a collection and conversion of the optical signal, where m and n are natural numbers.
In above-mentioned solutions, during the exposure period, a partial exposure of non-global exposure or a drum exposure method is used for a larger array.
For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, which are incorporated in the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure and together with the description serve to explain the principle of the present disclosure.
In order to make objectives, technical solutions and advantages of the present disclosure more apparent and understandable, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.
Embodiments of the present disclosure will be described below with reference to the accompanying drawings. It should be understood, however, that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed descriptions, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. It is obvious, however, that one or more embodiments may be implemented without these specific details. In addition, in the following descriptions, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concept of the present disclosure.
Due to the differences in the types of UTBB field effect transistors (NMOS/PMOS) and well doping (n-type and p-type), the optoelectronic field effect transistor provided in the present disclosure has four types in total, i.e., N-p (NMOS on p-type well) unit, N-n (NMOS on n-type well) unit, P-p (PMOS on p-type well) unit, and P-n (PMOS on n-type well) unit. The four types of photoelectric field effect transistors exhibit different photosensitive characteristics under lighting conditions, where the source/drain current IDS decreases when N-p unit and P-n unit are exposed, and the source/drain current IDS increases when N-n unit and P-p unit are exposed.
Based on complementary optoelectronic characteristics of the UTBB photoelectric field effect transistor described above, i.e., the source/drain current IDS decreases when N-p unit and P-n unit are exposed, and the source/drain current IDS increases when N-n unit and P-p unit are exposed. The present disclosure provides a complementary phototransistor pixel unit capable of simultaneously calculating positive and negative weight values, where the complementary phototransistor pixel unit includes: a first photoelectric field effect transistor, where the first photoelectric field effect transistor is a photoelectric field effect transistor based on an ultra-thin body and buried oxide layer; and a second photoelectric field effect transistor, where the second photoelectric field effect transistor is a photoelectric field effect transistor based on an ultra-thin body and buried oxide layer, and a type of the second photoelectric field effect transistor is different from a type of the first photoelectric field effect transistor, where the first photoelectric field effect transistor and the second photoelectric field effect transistor are both four-end devices and are provided with a gate electrode G, a source electrode S, a drain electrode D, and a well base electrode B, and the source electrode S or the drain electrode D of the first photoelectric field effect transistor is connected to the source electrode S or the drain electrode D of the second photoelectric field effect transistor.
According to embodiments of the present disclosure, the first photoelectric field effect transistor and the second photoelectric field effect transistor each include: a doped well; and a UTBB field effect transistor formed on the doped well, where a doping type of the doped well is n-type or p-type, and the UTBB field effect transistor is an NMOS transistor or a PMOS transistor.
According to embodiments of the present disclosure, for the first photoelectric field effect transistor and the second photoelectric field effect transistor, when the doping types of the doping wells of the first photoelectric field effect transistor and the second photoelectric field effect transistor are the same, the types of the UTBB field effect transistors of the first photoelectric field effect transistor and the second photoelectric field effect transistor are different, and when the doping types of the doping wells of the first photoelectric field effect transistor and the second photoelectric field effect transistor are different, the types of the UTBB field effect transistors of the first photoelectric field effect transistor and the second photoelectric field effect transistor are the same.
The present disclosure adopts a pair of different types of photoelectric field effect transistors to form a complementary phototransistor pixel unit, which may simultaneously calculate positive and negative weight values without the need to design different readout and control circuits, simplifying the complexity of array structure and operation method.
In the complementary phototransistor pixel unit composed of N-p unit and N-n unit shown in
The complementary phototransistor pixel unit utilizes complementary photoelectric characteristics of the first photoelectric field effect transistor and the second photoelectric field effect transistor to input a negative weight into the exposed first photoelectric field effect transistor to complete operation, and input a positive weight into the exposed second photoelectric field effect transistor to complete operation, thereby allowing positive and negative weight operations to be compatible within one pixel unit.
The complementary phototransistor pixel unit could perform exposure, readout, and reset functions in operation, specifically including: during exposure, a collection and conversion of an optical signal in the pixel unit is implemented by controlling a flip of a voltage of the well base electrode; during readout, a device is turned on or off by controlling a flip of a voltage of the gate electrode, and a weight value input is completed by controlling a flip of a voltage of the drain electrode, then an analog operation is completed inside the pixel unit, and a result is represented by a common source current; and during reset, a reset function of the pixel unit is completed by controlling a level signal of each port to return to zero, so as to prepare for a next exposure.
An operation method is that: VBp and VBn complete an exposure process by regulating a well voltage, achieving the collection and conversion of light signal in the pixel unit; VGp and VGn determine the gating on and off of the device by regulating a gate voltage; VDp and VDn respectively carry positive and negative weight information in a form of voltage (if the weight is a negative value, the weight is input into the N-p unit through VDp; if the weight is a positive value, the weight is input into the N-n unit through VDn), so as to complete the operation process of positive/negative weight and input inside the unit; and the operation result is collected by IOUT.
Specifically, when the weight is a positive value, the exposure is implemented by regulating the well base voltage VBn of the N-n unit, the device selection is implemented by regulating the gate voltage VGn, the weight input is implemented by regulating the drain voltage VDn, and the operation result is collected at the common source electrode. Similarly, when the weight is a negative value, the calculation process is completed by regulating the voltage of each port of the N-p unit, and the process is similar, which will not be described in detail here.
In the complementary phototransistor pixel unit composed of P-p unit and P-n unit shown in
The complementary phototransistor pixel unit utilizes complementary photoelectric characteristics of the first photoelectric field effect transistor and the second photoelectric field effect transistor to input a positive weight into the exposed first photoelectric field effect transistor to complete operation, and input a negative weight into the exposed second photoelectric field effect transistor to complete operation, thereby allowing positive and negative weight operations to be compatible within one pixel unit.
The complementary phototransistor pixel unit could perform exposure, readout, and reset functions in operation, specifically including: during exposure, a collection and conversion of an optical signal in the pixel unit is implemented by controlling a flip of a voltage of the well base electrode; during readout, a device is turned on or off by controlling a flip of a voltage of the gate electrode, and a weight value input is completed by controlling a flip of a voltage of the source electrode, then an analog operation is completed inside the pixel unit, and a result is represented by a common drain current; and during reset, a reset function of the pixel unit is completed by controlling a level signal of each port to return to zero, so as to prepare for a next exposure.
In the complementary phototransistor pixel unit composed of N-p unit and P-p unit shown in
The complementary phototransistor pixel unit utilizes complementary photoelectric characteristics of the first photoelectric field effect transistor and the second photoelectric field effect transistor to input a negative weight into the exposed first photoelectric field effect transistor to complete operation, and input a positive weight into the exposed second photoelectric field effect transistor to complete operation, thereby allowing positive and negative weight operations to be compatible within one pixel unit.
The complementary phototransistor pixel unit could perform exposure, readout, and reset functions in operation, specifically including: during exposure, a collection and conversion of an optical signal in the pixel unit is implemented by controlling a flip of a voltage of the well base electrode; during readout, a device is turned on or off by controlling a flip of a voltage of the gate electrode, and a weight value input is completed by controlling a flip of a voltage of the drain electrode of the first photoelectric field effect transistor or a flip of a voltage of the source electrode of the second photoelectric field effect transistor, then an analog operation is completed inside the pixel unit, and a result is represented by a common output current; and during reset, a reset function of the pixel unit is completed by controlling a level signal of each port to return to zero, so as to prepare for a next exposure.
In the complementary phototransistor pixel unit composed of N-n unit and P-n unit shown in
The complementary phototransistor pixel unit utilizes complementary photoelectric characteristics of the first photoelectric field effect transistor and the second photoelectric field effect transistor to input a positive weight into the exposed first photoelectric field effect transistor to complete operation, input a negative weight into the exposed second photoelectric field effect transistor to complete operation, thereby allowing positive and negative weight operations to be compatible within one pixel unit.
The complementary phototransistor pixel unit could perform exposure, readout, and reset functions in operation, specifically including: during exposure, a collection and conversion of an optical signal in the pixel unit is implemented by controlling a flip of a voltage of the well base electrode; during readout, a device is turned on or off by controlling a flip of a voltage of the gate electrode, and a weight value input is completed by controlling a flip of a voltage of the drain electrode of the first photoelectric field effect transistor or a flip of a voltage of the source electrode of the second photoelectric field effect transistor, then an analog operation is completed inside the pixel unit, and a result is represented by a common output current; and during reset, a reset function of the pixel unit is completed by controlling a level signal of each port to return to zero, so as to prepare for a next exposure.
Based on the four complementary phototransistor pixel units composed of N-p unit and N-n unit, P-p unit and P-n unit, N-p unit and P-p unit, and N-n unit and P-n unit shown in
In the complementary phototransistor sensing and computing array structure adapted for high parallel vector-matrix multiplication provided in the present disclosure, a plurality of complementary phototransistor pixel units are arranged into an array structure to form a scale array. By utilizing the photoelectric complementary characteristics, an input matrix (such as an image) may be mapped into the array during exposure, and the specific row selection can be achieved through word lines (WL), a weight vector could be applied to bit lines (BL) of the rows with voltage, the current could be collected in source line (SL) of each column as an operation result, and therefore the calculation of the vector is completed.
Based on the above-mentioned principle, taking the complementary phototransistor sensing and computing array structure composed of complementary phototransistor pixel units as shown in
A connection relationship of the plurality of complementary phototransistor pixel units located in a same column of the complementary phototransistor sensing and computing array structure is as follows to achieve a collection of current along a column direction: IOUT ends of the plurality of complementary phototransistor pixel units located in the same column are all connected to a source line SL of the column. That is, the IOUT ends are connected to the source line SL of the column to achieve a collection of current along a column direction.
The above is an example of the complementary phototransistor sensing and computing array structure composed of complementary phototransistor pixel units shown in
Based on the complementary phototransistor sensing and computing array structure composed of complementary phototransistor pixel units shown in
Based on the complementary phototransistor sensing and computing array structure adapted for high parallel vector-matrix multiplication provided in the present disclosure, the present disclosure further provides a high parallel convolution operation method adapted for in-sense computation, and in the method a convolution kernel slides in an input matrix to complete an convolution operation, which may be divided into sub processes of sliding column vectors forming the convolution kernel slides in the input matrix to complete a product accumulation, and the timing sequence control may be adjusted through a form of vector-product accumulation operation to complete a convolution operation.
Based on the above principle, the high parallel convolution operation method adapted for in-sense computation proposed in the present disclosure includes following steps:
After completing the above-mentioned process, reset signals of each control line are reset to wait for a next operation process.
It should be noted that a one-exposure multi-reading mode is adopted when a convolution operation is performed on the array, so that a second exposure enabling control line EN− and a first exposure enabling control line EN+ of a specific row are exposed simultaneously during the exposure period to adapt to a readout of positive and negative weight values during the readout period, which is different from the above-mentioned single vector-matrix multiplication operation in which only EN− is selected or only EN+ is selected. In addition, for a case that a convolution step size is not 1, the array and method may still complete the operation, and only a selection and storage of the operation result at the source line SL needs to be adjusted.
In step S0, according to the polarity of the weight values of the convolution kernel to be input, the word line WL+ or WL− of the specific row is controlled to achieve row-wise selection. Then the rightmost column vector of the convolution kernel is input into the array through the bit line BL+ or BL−.
In step S1, the analog operation is completed inside the pixel unit. The results are output in parallel through the source line SL of each column. Then the filtered results are stored in registers.
In step S2, the remaining column vectors of the convolution kernel are input into the array from right to left. Repeat steps S0 and S1 until the leftmost column vector of the convolutional kernel completes the computation and the filtered results are stored.
In step S3, the addition circuit sums up the corresponding computing results obtained from each operation in the registers, resulting in an output row vector.
In step S4, by sequentially moving the operation rows downwards and repeating the calculations according to steps S0, S1, S2, and S3, until reaching the last row of the array, multiple output row vectors can be obtained. These output row vectors can be concatenated together to obtain the final output matrix.
Compared with the related art, the complementary phototransistor pixel unit capable of simultaneously calculating positive and negative weight values, the complementary phototransistor sensing and computing array structure adapted for high parallel vector-matrix multiplication and an operation method thereof, and the high parallelism convolution operation implementation method adapted for in-sensor computing provided in the present disclosure have following beneficial effects:
Those skilled in the art will appreciate that although the present disclosure has been illustrated and described with reference to specific exemplary embodiments of the present disclosure, they should understand that without departing from the spirit and scope of the present disclosure defined by the appended claims and their equivalents, various changes in forms and details may be made to the present disclosure. Therefore, the scope of the present disclosure should not be limited to the aforementioned embodiments, but should be determined not only by the appended claims, but also by the equivalents of the appended claims.
This application is a Section 371 National Stage Application of International Application No. PCT/CN2022/128624, filed on Oct. 31, 2022, entitled “COMPLEMENTARY PHOTOTRANSISTOR PIXEL UNIT, SENSING AND COMPUTING ARRAY STRUCTURE AND OPERATION METHOD THEREOF”, the content of which is hereby incorporated by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/CN2022/128624 | 10/31/2022 | WO |