Hewlett Packard Enterprise Development LP

Brent Buchanan

Le Zheng

John Paul Strachan

Emmanuelle J Merced Grafals

Ning Ge

Naveen Muralimanohar

Richard James Auletta

Martin Foltin

Yoocharn Jeon

Ali Shafiee Ardestani

Richard Stanley Williams

Jianhua Yang

Gregg Bernard Lesartre

Gary A Gibson

Erik Ordentlich

Adam L Ghozeil

Catherine Graves

Miao Hu

Robert J Brooks

Hans S Cho

James Ignowski

Clinton Harold Parker

Jeffrey Alan Lucas

Sity Lam

Phillip David Misek

Jacquelyn M Ingemi

Richard J Auletta

In one example in accordance with the present disclosure a device is described. The device includes at least two memristive cells. Each memristive cell includes a memristive element to store one component of a complex weight value. The device also includes a real input multiplier coupled to the memristive element to multiply an output signal of the memristive element with a real component of an input signal. An imaginary input multiplier of the device is coupled to the memristive element to multiply the output signal of the memristive element with an imaginary component of the input signal.

Performing complex multiply-accumulate operations

An example electronic device includes a crossbar array, row driver circuitry, and column output circuits for each of the column lines of the crossbar array. The crossbar array may include row lines, column lines, and memristors that each are connected between one of the row lines and one of the column lines. The row driver circuitry may be to apply a plurality of analog voltages to a first node during a plurality of time periods, respectively, and, for each of the row lines, selectively connect the row line to the first node during one of the plurality of time periods based on a digital input vector. The column output circuits may each include: an integration capacitor, a switch that is controlled by an integration control signal, and current mirroring circuitry. The current mirroring circuitry may be to, when the switch is closed, flow an integration current to or from an electrode of the integration capacitor whose magnitude mirrors a current flowing on the corresponding column line. The integration control signal may be to close the switch for a specified amount of time during each of the plurality of time periods.

Analog multiplier-accumulators

A circuit for a neuron of a multi-stage compute process is disclosed. The circuit comprises a weighted charge packet (WCP) generator. The circuit may also include a voltage divider controlled by a programmable resistance component (e.g., a memristor). The WCP generator may also include a current mirror controlled via the voltage divider and arrival of an input spike signal to the neuron. WCPs may be created to represent the multiply function of a multiply accumulate processor. The WCPs may be supplied to a capacitor to accumulate and represent the accumulate function. The value of the WCP may be controlled by the length of the spike in signal times the current supplied through the current mirror. Spikes may be asynchronous. Memristive components may be electrically isolated from input spike signals so their programmed conductance is not affected. Positive and negative spikes and WCPs for accumulation may be supported.

Memristor spiking architecture

In one example in accordance with the present disclosure a memristive bit cell is described. The memristive bit cell includes a memristive device switchable between states. The memristive device is to store information. The memristive bit cell also includes a first switch regulating component coupled to the memristive device. The first switch regulating component enforces compliance of the memristive device with a first property threshold when switching between states in a first direction. The first property threshold corresponds to a state of the memristive device. The memristive bit cell also includes a second switch regulating component coupled to the memristive device. The second switch regulating component enforces compliance of the memristive device with a second property threshold when switching between states in a second direction. The second property threshold corresponds to a state of the memristive device.

Memristive bit cell with switch regulating components

In the examples provided herein, an apparatus has a memristive element coupled to a pin of an integrated circuit, wherein the memristive element switches from a first resistance within a first range of resistance values to a second resistance within a second range of resistance values in response to an electrostatic discharge (ESD) event at the pin. The apparatus also has read circuitry coupled to the memristive element to determine whether a resistance of the memristive element is in the first or second range of resistance values, wherein the read circuitry includes a first transistor. Further, the coupling between the read circuitry and the memristive element does not include a direct path for current from the ESD event to a gate terminal of the first transistor.

Read circuitry for electrostatic discharge switching memristive element

The present disclosure provides a memristive array. The array includes a number of memristive devices. A memristive device is switchable between states and is to store information. The memristive array also includes a parallel reset control device coupled to the number of memristive devices in parallel. The parallel reset control device regulates a resetting operation for the number of memristive devices by regulating current flow through target memristive devices.

Memristive array with parallel reset control devices

An example device in accordance with an aspect of the present disclosure includes a first module, a second module, and a third module. The first module is coupled to an element whose status is to be determined, and the first module is to receive an input current that increases over time. The second module is to perform a temporal derivative of a voltage across the element. The third module is to provide an output signal based on a current behavior of the element, according to a change in voltage as a function of a change in current.

Current behavior of elements

In one example in accordance with the present disclosure a device is described. The device includes a cross-bar array of memristive elements. Each memristive element has a conductance value. The device also includes a column of offset elements. An offset element is coupled to a row of memristive elements and has a conductance value. The device also includes a number of accumulation elements. An accumulation element is coupled to a column of memristive elements. The accumulation element collects an intermediate output from the column and subtracts from the intermediate output an output from the column of offset elements.

Memristive arrays with offset elements

An example finite state machine may include a content-addressable memory. The content-addressable memory may include blocks that respectively store input-terms of the finite state machine. The finite state machine may be configured to, for each received input: select a subset of the blocks of the content addressable memory to enable for searching, the subset being selected based on a current state of the finite state machine, and determine a next state of the finite state machine by searching the currently enabled subset of blocks of the content addressable memory based on the input.

Finite state machines

A memristive array includes a number of bit cells, each bit cell including a memristive element and a selecting transistor serially coupled to the memristive element. The array also includes a waveform generation device coupled to the number of bit cells. The waveform generation device generates a shaped waveform to be applied to the number of bit cells to switch a state of the memristive element. The waveform generation device passes the shaped waveform to gates of the selecting transistors of the number of bit cells.

Memristive arrays with a waveform generation device

Examples disclosed herein relate to a circuit having first and second analog processors and an analog-to-digital converter coupled to the first and second analog processors. The first analog processor provides a first analog signal having a voltage representing a function of a first vector and a second vector. The second analog processor provides a second analog signal having a voltage representing a function of a binary inverse of the first vector and the second vector. The analog-to-digital converter receives the first analog signal and the second analog signal, compares a signal selected from a group consisting of the first analog signal and the second analog signal to a reference voltage and based on the comparison to the reference voltage, determines a digital result representing the function of the first vector and the second vector.

Signal conversion based on complimentary analog signal pairs

In one example in accordance with the present disclosure a control circuit is described. The control circuit includes a source following component to receive an input voltage and output a switching voltage. The circuit also includes an input leg of a current mirror coupled to the source following component. The input leg of the current mirror replicates the switching voltage to an output leg of the current mirror of a memristive bit cell. The circuit also includes a number of current control components. At least one of the current control components enforces a constant current through the source following component and other current control components maintain the input leg of the current mirror and the output leg of the current mirror at the same current.

Memristive control circuits with current control components

In the examples provided herein, an electrostatic discharge (ESD) recording circuit has a first memristive element coupled to a pin of an integrated circuit. The first memristive element switches from a first resistance to a second resistance when an ESD event occurs at the pin, and the first resistance is less than the second resistance. The ESD recording circuit also has shunting circuitry to shunt energy from an additional ESD event away from the first memristive element.

Electrostatic discharge memristive element switching

According to examples, an apparatus may include a ternary content addressable memory (TCAM) including a plurality of TCAM bit cells connected in a row along a match line. Each of the TCAM bit cells may store a bit of a TCAM word and the TCAM bit cells may drive a digital signal over the match line in response to a search word matching the TCAM word. The apparatus may include a resistive random-access memory (RRAM) comprising a row of RRAM bit cells connected to the TCAM via the match line. Each of the RRAM bit cells may store a bit of a RRAM word. The RRAM bit cells may output the RRAM word in response to the TCAM bit cells driving the digital signal over the match line.

TCAM-driven RRAM

According to an example, discrete-time analog filtering may include receiving an input signal, and sampling the input signal to determine sampled input signal values related to the input signal.

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Palo Alto, CA, United States of America

Brent Buchanan