Advanced Micro Devices Corporation

Fujitsu Corporation

Vincent C Leung

Pau-Ling Chen

Binh Quang Le

Shane Charles Hollmer

Michael S Chung

Masaru Yano

Shoichi Kawamura

Michael Van Buskirk

The present invention discloses an embedded and test mode timer circuit that is used to perform operations in an embedded mode and a plurality of test modes in a memory device. When the memory device is operating in the embedded mode, the embedded and test mode timer circuit is activated to automatically direct at least one logic circuit to execute logic tasks at predetermined times. When the memory device is operating in a test mode, the embedded and test mode timer circuit is activated to automatically direct a portion of the logic circuits to execute logic tasks at predetermined times and the remaining portion of the logic circuit are manually directed.

Integration of embedded and test mode timer

A non-volatile memory device includes a plurality of MOS transistors 34 and 36 connected to respective word lines 16 and 18 to allow individual pages of memory stored in the memory cells 8a, 10a and 8b, 10b on the respective word lines 16 and 18 to be erased and erase verified. A method of erasing a page of memory cells includes the steps of applying an erase voltage to one of the MOS transistors 16 and 18 to erase the page of memory cells along the respective word line, and applying an initial erase-inhibit floating voltage to other MOS transistors which are connected to the word lines unselected for page erase. In an erase verify mode, an erase verify voltage is applied to the word line which was selected for page erase in the erase mode, and an erase verify unselect voltage is applied to the word lines which was not selected for page erase.

Scheme for page erase and erase verify in a non-volatile memory array

In the programming of a non-volatile memory device, such as a NAND flash memory device 100, a positive bias voltage V.sub.bias is applied to a bit line 44 to set a respective memory gate 44a in a programmed state. In a further embodiment, the positive bias voltage V.sub.bias is obtained by dividing the select drain gate voltage V.sub.cc using two resistors 56 and 58 connected in series.

Bit line biasing method to eliminate program disturbance in a

Two NMOS boost transistors have their sources connected to the high voltage input while their drains and gates are cross-connected. Two coupling capacitors connect two alternate phase clocks to the gates of the two cross-connected boost transistors. An NMOS pass transistor has its gate connected to the drain of one of the NMOS boost transistors, its source connected to the high voltage input, and its drain connected to the output. In an embodiment, two diode-connected regulation transistors connect the gates of the boost transistors to the high voltage input. These connections insure that the gates of the boost transistors and the gate of the pass transistor never reach voltages higher than one threshold voltage above the high voltage input. In another embodiment, two discharge transistors have their drains connected to a decode input, their sources connected to the gates of the boost transistors, and their gates connected to the positive power supply. By setting the decode input at zero volts, the voltages at the gates of the boost transistors and of the pass transistor are held at zero volts, thus disabling them. In the preferred embodiment, both the regulation transistors and the discharge transistors are included in the high voltage pass gate.

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Mountain View, CA, United States of America

Vincent C Leung