Semiconductor device and electronic device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorJun Koyama
Life of this patent
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Abstract
To provide a semiconductor device with such a new structure that the effect of variation in transistor characteristics can be reduced to achieve less variation in the output voltage of a memory cell. A memory cell includes a source follower (common drain) transistor for reading data held in a gate. A voltage applied to a transistor generating a reference current flowing through the memory cell is determined so that a gate-source voltage is approximately equal to the threshold voltage of the transistor. With such a structure, data stored in the memory cell can be read as a voltage that is less influenced by variation of transistors such as the field-effect mobility and the size.
Claims19
A semiconductor device comprising:
- a memory cell including a first transistor configured to write data and a second transistor configured to hold the data in a gate and read the data in accordance with a potential of the gate;
- and
- a reference current generation circuit including a third transistor configured to determine a current flowing between a source and a drain of the second transistor,
- wherein a voltage source is provided between a gate and a source of the third transistor, and
- wherein the second transistor is a common drain transistor.
A semiconductor device comprising
- a memory cell including a first transistor configured to write data and a second transistor configured to hold the data in a gate and read the data in accordance with a potential of the gate;
- and
- a reference current generation circuit including a third transistor configured to determine a current flowing between a source and a drain of the second transistor,
- wherein the second transistor is a common drain transistor,
- wherein a voltage source is provided between a gate and a source of the third transistor, and
- wherein the reference current generation circuit determines a voltage applied between the gate and the source of the third transistor so as to be substantially equal to a threshold voltage of the third transistor, thereby determining the current.
A semiconductor device comprising:
- a memory cell including a first transistor configured to write data, a second transistor configured to hold the data in a gate and read the data in accordance with a potential of the gate, and a capacitor electrically connected to the gate of the second transistor;
- and
- a reference current generation circuit including a third transistor configured to determine a current flowing between a source and a drain of the second transistor,
- wherein a voltage source is provided between a gate and a source of the third transistor, and
- wherein the second transistor is a common drain transistor.
Dependencies are inferred from the claim text.