Toshiba Memory Corporation

Kabushiki Kaisha Toshiba

Junji Musha

Mizuki Kaneko

Mizuho Yoshida

A charge pump includes a capacitor, a first transistor that is electrically connected between a first terminal of the first capacitor and ground, and a second transistor that is electrically connected between a second terminal of the first capacitor and an output node. During a first operation mode of the charge pump, a voltage that is boosted using the capacitor is output through the output node, and during a second operation mode of the charge pump, the first transistor and the second transistor are maintained in an ON state.

Charge pump and voltage generation circuit

A semiconductor memory device includes a first word line and a second word line that are adjacent to each other, a first voltage boosting circuit configured to generate a first voltage based on a clock signal, a second voltage boosting circuit configured to generate a second voltage lower than the first voltage based on the clock signal, a counter, and a determination circuit. The counter counts a first number of clock cycles of the clock signal during a first period in which the first voltage boosting circuit generates the first voltage and applies the first voltage to the first word line while the second voltage boosting circuit generates the second voltage and applies the second voltage to the second word line, and a second number of clock cycles of the clock signal during a second period in which the first voltage boosting circuit generates the first voltage while the first word line is electrically disconnected from the first voltage boosting circuit. The determination circuit compares the first number of clock cycles and the second number of clock cycles to determine whether or not a leakage exists in the word lines.

Semiconductor memory device and memory system

A semiconductor memory device includes a memory cell array, a voltage generation circuit that generates a voltage applied to the memory cell array, the voltage generation circuit including a plurality of boosting circuits connected in series between an input terminal and an output terminal, and a switching circuit configured to short-circuit one or more of the boosting circuits to the input terminal, and a control circuit that controls a conduction state of the switching circuit to vary the number of boosting circuits that are driven to generate the voltage applied to the memory cell array.

Growing community of inventors

Yokohama Kanagawa, Japan

Junji Musha