Qualcomm Incorporated

Fairchild Semiconductor Corporation

Yonsei University

Mehdi Hamidi Sani

Sei Seung Yoon

Seung Hyuk Kang

De Dzwo Hsu

Willard Kraig Bucklen

Seong-Ook Jung

Nan Chen

Cheng Zhong

Gurkanwal Singh Sahota

Gregory Ameriada Uvieghara

Sassan Shahrokhinia

Jisu Kim

Mohamed Hassan Abu-Rahma

Esin Terzioglu

Anil Chowdary Kota

Ritu Chaba

Abhay S Dixit

Vivek Mohan

Anosh Bomi Davierwalla

Dongkyu Park

Jee-Hwan Song

Gregory A Uvieghara

Anosh B Davierwalla

Memory devices and methods of reducing leakage current therein are disclosed. The memory device includes a memory core array including a plurality of bitlines, and peripheral logic configured to interface with the memory core array. The memory device further includes a footswitch configured to isolate the peripheral logic from a ground voltage, and a headswitch configured to isolate a precharge current path from the plurality of bit lines of the memory core array. Leakage current within the memory device may be reduced via the isolation provided by the footswitch and the headswitch.

Reducing leakage current in a memory device

In a particular embodiment, an apparatus includes a one-time programmable (OTP) memory circuit configured to be responsive to a programming voltage. The OTP memory circuit includes an OTP memory array including OTP memory cells, a first power switch configured to decouple the OTP memory array from the programming voltage, and a second power switch configured to decouple a subset of the OTP memory cells from the programming voltage.

Circuits configured to remain in a non-program state during a power-down event

In a particular embodiment, a memory device is disclosed that includes a memory cell including a resistance-based memory element coupled to an access transistor. The access transistor has a first oxide thickness to enable operation of the memory cell at an operating voltage. The memory device also includes a first amplifier configured to couple the memory cell to a supply voltage that is greater than a voltage limit to generate a data signal based on a current through the memory cell. The first amplifier includes a clamp transistor that has a second oxide thickness that is greater than the first oxide thickness. The clamp transistor is configured to prevent the operating voltage at the memory cell from exceeding the voltage limit.

Memory device for resistance-based memory applications

Systems, circuits and methods for controlling write operations in Spin Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM) are disclosed. A reduced bit cell size is achieved by arranging the source lines (SL) substantially in parallel with the word lines (WL) and substantially perpendicular to the bit lines (BL). Further, in one embodiment during a write operation, a high logic/voltage level is applied to the bit lines of unselected bit cells to prevent an invalid write operation.

Write operation for spin transfer torque magnetoresistive random access memory with reduced bit cell size

Systems, circuits and methods for controlling the word line voltage applied to word line transistors in Spin Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM) are disclosed. One embodiment is directed to a STT-MRAM including a bit cell having a magnetic tunnel junction (MTJ) and a word line transistor. The bit cell is coupled to a bit line and a source line. A word line driver is coupled to a gate of the word line transistor. The word line driver is configured to provide a word line voltage greater than a supply voltage below a transition voltage of the supply voltage and to provide a voltage less than the supply voltage for supply voltages above the transition voltage.

Word line voltage control in STT-MRAM

Circuitry that generates an interface signal between a first and a second integrated circuit (IC). The circuitry includes a reference circuit that provides a reference signal, an interface circuit, and a circuit element. The interface circuit is implemented on the first IC, operatively couples to the reference circuit, receives the reference signal and a data input, and generates the interface signal. The circuit element is implemented on the second IC, operatively couples to the control circuit, receives the interface signal, and provides an output signal. The reference signal can be a voltage or a current signal, and can be generated in the first or second IC. The interface circuit can be implemented with a current mirror coupled to a switch array, and can be oversampled to ease the filtering requirement. The interface signal can be a differential current signal having multiple (e.g., four, eight, or more) bits of resolution. The circuit element can be, for example, a VGA, a modulator, or other circuits.

Interface between digital and analog circuits

A resistance based memory circuit is disclosed. The circuit includes a first transistor load of a data cell and a bit line adapted to detect a first logic state. The bit line is coupled to the first transistor load and coupled to a data cell having a magnetic tunnel junction (MTJ) structure. The bit line is adapted to detect data having a logic one value when the bit line has a first voltage value, and to detect data having a logic zero value when the bit line has a second voltage value. The circuit further includes a second transistor load of a reference cell. The second transistor load is coupled to the first transistor load, and the second transistor load has an associated reference voltage value. A characteristic of the first transistor load, such as transistor width, is adjustable to modify the first voltage value and the second voltage value without substantially changing the reference voltage value.

Balancing a signal margin of a resistance based memory circuit

Systems, circuits and methods for determining read and write voltages for a given word line transistor in Spin Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM) are disclosed. A first voltage can be supplied to the write operations so that the write operations occur in the saturation region of the word line transistor. A second voltage, which is less than the first voltage, can be supplied for read operations so that the read operations occur in the linear region of the word line transistor.

Spin transfer torque magnetoresistive random access memory and design methods

A transceiver interface for data transfer between two integrated circuits (ICs or 'chips') utilizes a current mode technique rather than conventional voltage mode differential signaling techniques. A current pulse is injected into one of two transmission wires based on a signal value to be transmitted (e.g., logic '0' or &#x201c;1&#x201d;) by a driver on a transmitting chip. The current pulse is received as a differential current signal at a receive block in a receiving chip. The differential signal is converted to a low swing differential voltage signal by current comparators. The differential voltage signal may be detected by an op-amp receiver which outputs the appropriate signal value.

Current mode interface for off-chip high speed communication

A CMOS integrated circuit (e.g., an SRAM or a DRAM) is partitioned into a core block, a peripheral block, and a retention block. The core block includes circuits (e.g., memory cells) that are powered on at all times and is coupled directly to power supply and circuit ground. The peripheral block includes circuits that may be powered on or off and are coupled to the power supply via a head switch and/or to circuit ground via a foot switch. The switches and the core block may be implemented with high threshold voltage (high-Vt) FET devices to reduce leakage current. The peripheral block may be implemented with low-Vt FET devices for high-speed operation. The retention block includes circuits (e.g., pull-up devices) that maintain signal lines (e.g., word lines) at a predetermined level so that the internal states of the core block are retained when the peripheral block is powered off.

Leakage current reduction for CMOS memory circuits

A VGA to analog video converter is useful e.g. for displaying video and/or graphics data from a computer onto a large screen television or television monitor. The RGB video signals output from the personal computer are first converted to digital form. The analog-to-digital converter which does this is clocked by a clock signal generated by a phase-locked loop using the horizontal synchronizing signal from the personal computer. The digital RGB signals are then converted to a YCbCR format. A flicker filter eliminates the flickering appearing on the TV monitor by operating on the luminance (Y) component. The YCbCr signals are encoded into NTSC or PAL Standard, and output in composite analog video or S-VHS format. A color subcarrier synthesizer generates the color subcarrier signal to generate an accurate subcarrier frequency for the video output signals. An analog-to-digital clock phase adjustment is used to ensure that the input RGB signals are sampled at the proper instant by the analog-to-digital converters.

Video signal converter for converting non-interlaced to composite video

Techniques for replacing and eliminating paths causing channel leakage current. In one embodiment, one or more precharge enable transistors and a precharge enable signal are added to a circuit configuration. The precharge enable transistors are designed to remain on and simply pass a signal in a properly functioning path. When a leakage path is identified, such as during IDDQ testing, the precharge enable signal is set to turn off the precharge enable transistors. When the precharge enable transistors are off, the leakage path is disrupted, and the leakage current stopped. The path may be replaced with a redundant path.

Memory bit line leakage repair

An integrated circuit including a Multi-Threshold CMOS (MTCMOS) latch combining low voltage threshold CMOS circuits with high voltage threshold CMOS circuits. The low voltage threshold circuits including a majority of the circuits in the signal path of the latch to ensure high performance of the latch. The latch further including high voltage threshold circuits to eliminate leakage paths from the low voltage threshold circuits when the latch is in a sleep mode. A single-phase latch and a two-phase latch are provided. Each of the latches is implemented with master and slave registers. Data is held in either the master register or the slave register depending on the phase or phases of the clock signals. A multiplexer may alternatively be implemented prior to the master latch for controlling an input signal path during sleep and active modes of the latch and for providing a second input signal path for test.

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San Diego, CA, United States of America

Mehdi Hamidi Sani