Mitsubishi Denki Kabushiki Kaisha

Motoharu Ishii

Shinichi Kobayashi

Atsushi Ohba

Tomoshi Futatsuya

Akira Hosogane

Hiroaki Nakai

Masashi Wada

Akinori Matsuo

Kayoko Omoto

A charge pump circuit comprising: a first reverse current prevention circuit connected between an external power supply and a first internal node; a first output node, connected to the first internal node, for outputting a first output potential; a second reverse current prevention circuit connected between a second power supply node receiving ground potential and a second internal node; and power supply generation circuit, connected between the first internal node and second internal node, for enhancing the potential of the second internal node as compared to that of the first internal node, wherein the power supply generation circuit is formed on or within a semiconductor substrate, and includes a diode element provided so as to flow a current from the first internal node to the second internal node, and a capacitor having one electrode connected to the first and second nodes, and the other electrode provided with a clock signal, thereby enabling higher outputs on both positive and negative voltages.

Charge pump circuit for generating positive and negative voltage with reverse current prevention circuit and a nonvolatile memory using the same

In response to complementary clock signals provided from a driver, a charge pump operates to provide an output voltage which is a down-converted negative voltage. The voltage between this output voltage and a predetermined positive reference voltage is capacitance-divided by capacitors. The capacitance-divided positive voltage is applied to a comparator, whereby a reference voltage is compared with the above positive voltage. An output signal of the comparator is applied to the driver. In response, the driver controls the operation of the charge pump, whereby the output voltage is clamped at a predetermined voltage level for output.

Semiconductor device allowing generation of desired internal voltage at

It is assumed that, in each memory cell array, a first bit line corresponds to a selected address. In this case, a potential on only the first bit line attains H-level. Data to be loaded is supplied to a latch circuit corresponding to the first bit line through a data line arranged independently of the bit line. All the bit lines are reset upon every completion of loading of data of 1 byte. Therefore, rapid data reading can be performed even when data is to be read from a memory cell array immediately after the data is loaded into a latch circuit, or destruction of data already loaded into the latch circuit can be prevented. Further, a circuit area can be reduced.

Nonvolatile semiconductor memory device having data line dedicated to

A bit line reset transistor resets every second bit line of a plurality of bit lines to be write-verified. At this time, a transfer gate disconnects a column latch from the unreset bit line. Then, the unreset bit line is precharged in accordance with data of the column latch, while applying a verify voltage to a word line. Then, a source line transistor grounds a source line, and the bit line is connected to the column latch, so that data corresponding to a value of a threshold voltage of the memory cell is held by the column latch, and a write verifying operation is performed.

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Hyogo, Japan

Motoharu Ishii