# US 5,706,242 A · Semiconductor device having a controllable voltage supply

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- Number: US 5,706,242 A
- Document ID: US5706242A
- Status: Granted
- Kind: A
- Application number: 08/697,508
- Filed: 1996-08-26
- Granted: 1998-01-06
- Earliest claimed: 1994-06-28
- Assignees: Matsushita Electric Industrial Co., Ltd.
- Inventors: Hiroshige Hirano; Toshiyuki Honda
- Web page: https://patentgrep.com/patent/US5706242A

## CPC

- G11C 7/067: {Single-ended amplifiers}
- G11C 5/143: {Detection of memory cassette insertion or removal; Continuity checks of supply or ground lines; Detection of supply variations, interruptions or levels (G11C5/148 takes precedence); Switching between alternative supplies (G11C5/141 takes precedence)}
- G11C 16/26: Sensing or reading circuits; Data output circuits
- G11C 2207/063: Current sense amplifiers
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

A semiconductor device includes a nonvolatile memory cell and a current detecting type sense amplifier for detecting a current flowing through a data line into the memory cell. The semiconductor device is further provided with an element for outputting a first voltage detecting signal when a detected supply voltage exceeds a set value and outputting a second voltage detecting signal when the detected supply voltage does not exceed the set value. The sense amplifier includes an element for switching a dependent characteristic of a level sensing current upon the supply voltage to be a higher response to the first voltage detecting signal. Thus, error reading of a data from the memory cell, which can be otherwise caused under application of a low supply voltage, can be avoided.

## Claims

### Claim 1

A semiconductor device comprising:
a memory cell;
a signal line connected to the memory cell;
voltage supplying means for supplying a supply voltage to the signal line;
supply voltage detecting means connected to the voltage supply means, for outputting a first voltage detecting signal when the supply voltage exceeds a set value and outputting a second voltage detecting signal when the supply voltage does not exceed the set value; and
controlling means for setting a potential of the signal line equal to the supply voltage when the first voltage detecting signal is received, while boosting a potential of the signal line higher than the supply voltage when the second voltage detecting signal is received.

### Claim 2 (depends on 1)

The semiconductor device of claim 1, wherein the signal line is a word line of the memory cell.

### Claim 3 (depends on 1)

The semiconductor device of claim 1, wherein the signal line is a data line of the memory cell.

### Claim 4

A semiconductor device comprising:
a memory cell;
a signal line connected to the memory cell;
voltage supplying means for supplying a supply voltage to the signal line;
supply voltage detecting means connected to the voltage supplying means, for outputting a first voltage detecting signal when the supply voltage exceeds a set value and outputting a second voltage detecting signal when the supply voltage does not exceed the set value;
controlling means for setting a potential of the signal line equal to the supply voltage when the first voltage detecting signal is received, while boosting a potential of the signal line higher than the supply voltage when the second voltage detecting signal is received; and
limiting means for limiting the potential of the signal line to be set by the controlling means to any potential that is higher than the supply voltage by a given value.

### Claim 5 (depends on 4)

A semiconductor device of claim 4, wherein the signal is a word line of the memory cell.

### Claim 6 (depends on 4)

A semiconductor device of claim 4, wherein the signal is a data line of the memory cell.