Qualcomm Incorporated

Yonsei University

Youngdon Jung

Seung Hyuk Kang

Jung Pill Kim

Seong-Ook Jung

Jisu Kim

Kyungho Ryu

A low sensing current non volatile flip flop includes a first stage to sense a resistance difference between two magnetic tunnel junctions (MTJs) and a second stage having circuitry to amplify the output of the first stage. The output of the first stage is initially pre-charged and determined by the resistance difference of the two MTJs when the sensing operation starts. The first stage does not have a pull-up path to a source voltage (VDD), and therefore does not have a DC path from VDD to ground during the sensing operation. A slow sense enable (SE) signal slope reduces peak sensing current in the first stage. A secondary current path reduces the sensing current duration of the first stage.

Low sensing current non-volatile flip-flop

A flip-flop has an output control node and an isolation switch selectively couples a retention sense node to the output control node. A sense circuit selectively couples an external sense current source to the retention sense node and to magnetic tunneling junction (MTJ) elements. Optionally a write circuit selectively injects a write current through one MTJ element and then another MTJ element. Optionally, a write circuit injects a write current through a first MTJ element concurrently with injecting a write current through a second MTJ element.

Non-volatile flip-flop

A resistance based memory sensing circuit has reference current transistors feeding a reference node and a read current transistor feeding a sense node, each transistor has a substrate body at a regular substrate voltage during a stand-by mode and biased during a sensing mode at a body bias voltage lower than the regular substrate voltage. In one option the body bias voltage is determined by a reference voltage on the reference node. The substrate body at the regular substrate voltage causes the transistors to have a regular threshold voltage, and the substrate body at the body bias voltage causes the transistors to have a sense mode threshold voltage, lower than the regular threshold voltage.

Growing community of inventors

Seoul, South Korea

Youngdon Jung