Stmicroelectronics International N.v.

Stmicroelectronics (crolles 2) Sas

Stmicroelectronics Pvt. Ltd.

Harsh Rawat

Kedar Janardan Dhori

Promod Kumar

Nitin Chawla

Manuj Ayodhyawasi

Praveen Kumar Verma

Abhishek Pathak

Tanuj Kumar

Hitesh Chawla

Bhupender Singh

Piyush Jain

Tanmoy Roy

Nitin Jain

Swapnil Bahl

Vinay Kumar

Amit Chhabra

Gangaikondan Subramani Visweswaran

Anand Kumar Mishra

Christophe Lecocq

PraveenKumar Verma

Jatin Fultaria

An in-memory computation circuit includes a memory array with SRAM cells connected in rows by word lines and in columns by bit lines. A row controller circuit simultaneously actuates word lines in parallel for an in-memory compute operation. A column processing circuit includes a read circuit that operates to reduce sensitivity to variation in bit line read current. Additionally, a testing circuit senses analog signals on the complementary bit lines to identify one of the complementary bit lines as having a less variable read current. That identified one of the complementary bit lines is coupled to the read circuit for the in-memory compute operation.

Enhanced accuracy of bit line reading for an in-memory compute operation by accounting for variation in read current

An in-memory computation circuit includes a memory array with SRAM cells connected in rows by word lines and in columns by bit lines. A row controller circuit simultaneously actuates word lines in parallel for an in-memory compute operation. A column processing circuit includes a current mirroring circuit that mirrors the read current developed on each bit line in response to the simultaneous actuation to generate a decision output for the in-memory compute operation. A bias voltage for word line driver and a configuration of the current mirroring circuit to inhibit drop of a voltage on the bit line below a bit flip voltage during execution of the in-memory compute operation. The mirrored read current is integrated by an integration capacitor to generate an output voltage that is converted to a digital signal by an analog-to-digital converter circuit.

Bit line read current mirroring circuit for an in-memory compute operation where simultaneous access is made to plural rows of a static random access memory (SRAM)

A memory circuit includes an address port, a data input port and a data output port. An upstream shadow logic circuit is coupled to provide address data to the address port of the memory circuit and input data to the data input port of the memory circuit. A downstream shadow logic circuit is coupled to receive output data from the data output port of the memory circuit. The memory circuit includes a bypass path between the address port and the data output port. This bypass path is activated during a testing operation to pass bits of the address data (forming test data) applied by upstream shadow logic circuit from the address port to the data output port.

At-speed transition fault testing for a multi-port and multi-clock memory

An in-memory computation circuit includes a memory array including sub-arrays of with SRAM cells connected in rows by word lines and in columns by local bit lines. A row controller circuit selectively actuates one word line per sub-array for an in-memory compute operation. A global bit line is capacitively coupled to many local bit lines in either a column direction or row direction. An analog global output voltage on each global bit line is an average of local bit line voltages on the capacitively coupled local bit lines. The analog global output voltage is sampled and converted by an analog-to-digital converter (ADC) circuit to generate a digital decision signal output for the in-memory compute operation.

In-memory computation circuit using static random access memory (SRAM) array segmentation

The memory array of a circuit includes sub-arrays with memory cells arranged in a row-column matrix where each row includes a word line and each sub-array column includes a local bit line. A control circuit supports two modes of circuit operation: a first mode where only one word line in the memory array is actuated during a memory read and a second mode where one word line per sub-array are simultaneously actuated during the memory read. An input/output circuit for each column includes inputs to the local bit lines of the sub-arrays, a column data output coupled to the bit line inputs, and a sub-array data output coupled to each bit line input. In memory computation operations are performed in the second mode as a function of feature data and weight data stored in the memory.

Memory architecture supporting both conventional memory access mode and digital in-memory computation processing mode

An in-memory computation circuit includes a memory array with SRAM cells connected in rows by word lines and in columns by bit lines. Each row includes a word line drive circuit powered by an adaptive supply voltage. A row controller circuit simultaneously actuates word lines in parallel for an in-memory compute operation. A column processing circuit processes analog voltages developed on the bit lines in response to the simultaneous actuation to generate a decision output for the in-memory compute operation. A voltage generator circuit generates the adaptive supply voltage for powering the word line drive circuits during the simultaneous actuation. A level of the adaptive supply voltage is modulated dependent on integrated circuit process and/or temperature conditions in order to optimize word line underdrive performance and inhibit unwanted memory cell data flip.

Adaptive word line underdrive control for an in-memory compute operation where simultaneous access is made to plural rows of a static random access memory (SRAM)

A memory circuit includes an array of memory cells arranged in rows and columns. A word line is connected to the memory cells of each row. A row decoder circuit operates in response to an internal clock and an address to selectively apply a word line signal to one word line and further generate a dummy word line signal. A control circuit includes a clock generator that generates the internal clock which is reset in response to a reset signal. A first delay circuit receives the dummy word line signal and outputs a first delayed dummy word line signal. A second delay circuit receives the dummy word line signal and outputs a second delayed dummy word line signal. A multiplexer circuit selects between the first and second delayed dummy word line signals for output as the reset signal in response to a logic state of a mode control signal.

Tuning of read/write cycle time delay for a memory circuit dependent on operational mode selection

A read-modify-write operation is performed, within a single cycle of a clock signal, by: decoding an address to select a word line of a memory; applying a word line signal at a first voltage level to the selected word line; reading a current data word from a data word location in the memory; reducing the word line signal from the first voltage level to the second voltage level; performing a mathematical modify operation internally within the memory on the current data word to generate a modified data word; increasing the word line signal from the second voltage level to the first voltage level; and writing the modified data word back to the location in the memory.

Static random access memory supporting a single clock cycle read-modify-write operation with a modulated word line assertion

A circuit includes a memory array with SRAM cells connected in rows by word lines and in columns by bit lines. A row controller circuit simultaneously actuates, through a word line driver circuit for each row, word lines in parallel for an in-memory compute operation. A column processing circuit processes analog voltages developed on the bit lines in response to the simultaneous actuation to generate a decision output for the in-memory compute operation. A bit line clamping circuit includes a sensing circuit that compares the analog voltages on a given pair of bit lines to a threshold voltage. A voltage clamp circuit is actuated in response to the comparison to preclude the analog voltages on the given pair of bit lines from decreasing below a clamping voltage level.

Selective bit line clamping control for an in-memory compute operation where simultaneous access is made to plural rows of a static random access memory (SRAM)

A memory array includes a plurality of bit-cells arranged as a set of rows of bit-cells intersecting a plurality of columns. The memory array also includes a plurality of in-memory-compute (IMC) cells arranged as a set of rows of IMC cells intersecting the plurality of columns of the memory array. Each of the IMC cells of the memory array includes a first bit-cell having a latch, a write-bit line and a complementary write-bit line, and a second bit-cell having a latch, a write-bit line and a complementary write-bit line, wherein the write-bit line of the first bit-cell is coupled to the complementary write-bit line of the second bit-cell and the complementary write-bit line of the first bit-cell is coupled to the write-bit line of the second bit-cell.

Bit-cell architecture based in-memory compute

An in-memory computation circuit includes a memory array with SRAM cells connected in rows by word lines and in columns by bit lines. Body bias nodes of the transistors in each SRAM cell are biased by a modulated body bias voltage. A row controller circuit simultaneously actuates word lines in parallel for an in-memory compute operation. A column processing circuit processes analog voltages developed on the bit lines in response to the simultaneous actuation to generate a decision output for the in-memory compute operation. A voltage generator circuit switches the modulated body bias voltage from a non-negative voltage level to a negative voltage level during the simultaneous actuation. The negative voltage level is adjusted dependent on integrated circuit process and/or temperature conditions in order to optimize protection against unwanted memory cell data flip.

Adaptive body bias management for an in-memory compute operation where simultaneous access is made to plural rows of a static random access memory (SRAM)

The memory array of a memory includes sub-arrays with memory cells arranged in a row-column matrix where each row includes a word line and each sub-array column includes a local bit line. A row decoder circuit supports two modes of memory circuit operation: a first mode where only one word line in the memory array is actuated during a memory read and a second mode where one word line per sub-array are simultaneously actuated during the memory read. An input/output circuit for each column includes inputs to the local bit lines of the sub-arrays, a column data output coupled to the bit line inputs, and a sub-array data output coupled to each bit line input. Both BIST and ATPG testing of the input/output circuit are supported. For BIST testing, multiple data paths between the bit line inputs and the column data output are selectively controlled to provide complete circuit testing.

Built-in self test circuit for segmented static random access memory (SRAM) array input/output

A method of corrupting contents of a memory array includes asserting a signal at a reset node to thereby cause starving of current supply to the memory array, and selecting bit lines and complementary bit lines associated with desired columns of the memory array that contain memory cells to have their contents corrupted. For each desired column, a logic state of its bit line and complementary bit line are forced to a same logic state. Each word line associated with desired rows of the memory array that contains memory cells to have their contents corrupted is simultaneously asserted, and then simultaneously deasserted to thereby place each memory cell to have its contents corrupted into a metastable state during a single clock cycle.

SRAM with fast, controlled peak current, power efficient array reset, and data corruption modes for secure applications

SRAM cells are connected in columns by bit lines and connected in rows by first and second word lines coupled to first and second data storage sides of the SRAM cells. First the first word lines are actuated in parallel and then next the second word lines are actuated in parallel in first and second phases, respectively, of an in-memory compute operation. Bit line voltages in the first and second phases are processed to generate an in-memory compute operation decision. A low supply node reference voltage for the SRAM cells is selectively modulated between a ground voltage and a negative voltage. The first data storage side receives the negative voltage and the second data storage side receives the ground voltage during the second phase. Conversely, the second data storage side receives the negative voltage and the first data storage side receives the ground voltage during the first phase.

Serial word line actuation with linked source voltage supply modulation for an in-memory compute operation where simultaneous access is made to plural rows of a static random access memory (SRAM)

A method of memory reset includes precharging bit lines of a memory array, asserting a signal at a reset node to remove the precharge voltage, and selecting write drivers associated with the bit lines associated with columns of the memory array that contain memory cells to be reset, with the assertion of the signal at the reset node also resulting in application of desired logic states to inputs of the selected write drivers to cause those selected write drivers to change a logic state of the bit lines associated with those write drivers. The method continues with asserting each word line associated with a row of the memory that contains memory cells to be reset to write desired logic states to all of the memory cells of the columns and rows of the memory to be reset during a single clock cycle, and then deasserting those word lines.

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Haryana, India

Harsh Rawat