Renesas Electronics Corporation

Toyota Jidosha Kabushiki Kaisha

Nec Electronics Corporation

Masahiko Kashimura

Masakazu Amanai

Masato Taki

Yoshihiro Nagai

Kazushi Yamanaka

Norihiro Honda

Hirofumi Oga

Booster circuit comprising: first transistor that is connected to first node; capacitor that has one end connected to first node, and that is charged with voltage of first node when first transistor is activated; and control signal generating circuit that provides control terminal of first transistor with control signal being in accordance with first clock, wherein when first transistor is de-activated, capacitor boosts voltage of first node to first voltage by voltage being applied to or end of capacitor, voltage applied to or end being at least &#xbd; as great as first supply voltage, and control signal generating circuit sets voltage of control signal when first transistor is de-activated to be first voltage of first node, and sets voltage of control signal when first transistor is activated to be voltage, difference between voltage and first voltage being equal to or smaller than value of first supply voltage.

Booster circuit

A nonvolatile memory device includes a memory cell that stores data by presence or absence of electrons accumulated in a floating gate, a read reference current generator that generates a read reference current for reading data from the memory cell based on a constant current from a constant current generator included therein, and a read voltage generator that generates a read voltage to be applied to a control gate of the memory cell during data reading. The read reference current generator generates a monitor voltage that varies according to variation of the read reference current and a threshold voltage of the memory cell. The read voltage generator generates the read voltage based on the monitor voltage.

Nonvolatile semiconductor memory device

A nonvolatile semiconductor memory includes a memory cell, a first gate control circuit that is coupled to the memory cell, and a second gate control circuit that is coupled to the memory cell. The memory cell includes a first gate electrode that is formed above a channel region in a semiconductor substrate, a second gate electrode that is formed beside the first gate electrode, and that is capacitively coupled with the first gate electrode through a first insulating layer, and a charge trapping layer that is formed between the channel region and the second gate electrode, and that includes a second insulating layer for trapping a charge. Data stored in a memory cell transistor including the second gate electrode changes depending on an amount of the charge trapped in the charge trapping layer. The first gate control circuit applies a potential to the first gate electrode, when reading the data stored in the memory cell transistor. The second gate control circuit brings the second gate electrode into a floating state, when the potential is applied to the first gate electrode.

Nonvolatile semiconductor memory, and method for reading data

A non-volatile memory device comprises a plurality of bit lines extending in a first direction, a plurality of word lines extending in a second direction substantially perpendicular to the first direction, a plurality of memory cells provided respectively so as to correspond to the positions of the intersections between the plurality of bit lines and the plurality of word lines, a plurality of source lines corresponding to a plurality of memory cells which are connected to a same bit line, a current source capable of supplying the constant current to a selected memory cell and the corresponding bit line and a voltage control circuit which keeps a voltage of a selected bit line equal to or higher than a predetermined voltage.

Growing community of inventors

Kawasaki, Japan

Masahiko Kashimura