EP0037285A2
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EP
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A memory device, more particularly word line drive circuitry for a memory device
Assignee: Fujitsu Ltd
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Filing: 1981-03-31
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Granted: —
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Expires: 2001-03-31
Abstract
Abstract Word lines Wo to Wn of the memory device are connected to work line drivers WDo to WDn to which are supplied selection signals Vxo to Vxn. When a section signal Vxo is high the word line Wo is selected, and when the selection signal Vxn is low the word line Wn is non-selected. The level of Vxo (for selected word line Wo) is different for write and read operations. In a write operation Vxo is higher than in a read operation. This is provided by word line selection level switching circuit comprising transistors T 1 , T 2 and current source lxw, and diodes Do to Dn. In a read operation a signal WE is high, and a current lxw flows through a load Rx connected to selected word driver WDo, thereby reducing selection voltage Vxo. In a write operation WE is relatively low so that current lxw does not flow through load Rx, so that Vxo has a high level (Vcc). The level of non-selected word lines is maintained independent of write and read operations.
Inventors
- 👤 Kazuhiro Toyoda
- 👤 Haruo Shimada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 18:51
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/41; G11C11/413; G11C11/414; G11C11/415; G11C8/00
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
222 words
A memory device, having an array of memory cells with word lines connected to the memory cells, comprising word drivers, for driving respective word lines of the device, operable to cause the potential of a selected word line to differ from that of a non-selected word line in dependence upon selection signals supplied to input terminals of the respective word drivers from respective word decoders, the word decoders being operable so that the potential of a selection signal supplied to the input terminal of a word driver of a selected word line differs from the potential of a selection signal supplied to the input terminal of a word driver of a non-selected word line, wherein the memory device further comprises a word line selection level switching circuit so connected in common to the word drivers via respective switching parts and so arranged as to cause the potential of a selection signal supplied to the input terminal of a word driver of a selected word line to differ from the potential of a selection signal supplied to the input terminal of a word driver of a non-selected word line by a greater amount in write operation than in read operation, whereby the potential difference between a selected and a non-selected word line is greater in a write operation than in a read operation.
Claim 2
Dependent Claim
222 words
A memory device, having an array of memory cells with word lines connected to the memory cells, comprising word drivers, for driving respective word lines of the device, operable to cause the potential of a selected word line to differ from that of a non-selected word line in dependence upon selection signals supplied to input terminals of the respective word drivers from respective word decoders, the word decoders being operable so that the potential of a selection signal supplied to the input terminal of a word driver of a selected word line differs from the potential of a selection signal supplied to the input terminal of a word driver of a non-selected word line, wherein the memory device further comprises a word line selection level switching circuit so connected in common to the word drivers via respective switching parts and so arranged as to cause the potential of a selection signal supplied to the input terminal of a word driver of a selected word line to differ from the potential of a selection signal supplied to the input terminal of a word driver of a non-selected word line by a greater amount in write operation than in read operation, whereby the potential difference between a selected and a non-selected word line is greater in a write operation than in a read operation.
Claim 3
Dependent Claim
109 words
A device as claimed in claim 1, wherein each word driver comprises a driver transistor having a collector connected to a first power supply line, an emitter connected to a respective one of the word lines,and a base, acting as the input terminal of the word driver, connected to the first power supply line via a load, and connected to one terminal of a respective one of the switching parts, which switching part has another terminal connected in common with such other terminals of all the switching parts and connected to the word line selection level switching circuit, which circuit is connected also to a second power supply line.
Claim 4
Dependent Claim
46 words
A device as claimed in claim 1 or 2, wherein each switching part comprises a rectifying circuit, and the word line selection level switching circuit has a current source, such that in a read operation the rectifying circuit and the current source form a current switch.
Claim 5
Dependent Claim
61 words
A device as claimed in claim 1, 2 or 3; wherein each switching part comprises a diode, a first terminal of which is connected to the input terminal of a respective word driver and a second terminal of which is connected to the word line selection level switching circuit, in common with the second terminals of all the other switching parts.
Claim 6
Dependent Claim
63 words
A device as claimed in claim 1, 2 or 3, wherein each switching part comprises a Schottky barrier diode, a first terminal of which is connected to the input terminal of a respective word driver and a second terminal of which is connected to the word line selection level switching circuit, in common with the second terminals of all the other switching parts.
Claim 7
Dependent Claim
62 words
A device as claimed in claim 1, 2 or 3, wherein each switching part comprises a transistor with a base and a collector interconnected, and with the collector connected to the input terminal of a respective word driver, and with an emitter connected to the word line selection level switching circuit, in common with the emitters of all the other switching parts.
Claim 8
Dependent Claim
73 words
A device as claimed in claim 1, 2 or 3, wherein each switching part comprises a transistor with resistors connected respectively between a base and a collector thereof and between the base and an emitter thereof, with the collector connected to the input terminal of a respective word driver, and with the emitter connected to the word line selection level switching circuit, in common with the emitters of all the other switching parts.
Claim 9
Dependent Claim
23 words
A device as claimed in claim 3, operable so that, in a read operation, the current source is connected to a rectifying circuit.
Claim 10
Dependent Claim
140 words
A device as claimed in claim 3 or claim 8, or any one of claims 4 to 7 read as appended to claim 3, - wherein the word line selection level switching circuit comprises a first transistor having a collector connected to a first power supply line, an emitter connected to an emitter of a second transistor and to the current source, which current source is connected between the emitters of the first and second transistors and a second power supply line, and a base connected for receiving a reference voltage, a collector of the second transistor being connected in common to the rectifying circuits and a base of the second transistor being connected to receive a control signal which is higher than the reference voltage in a read operation and lower than the reference voltage in a write operation.
Claim 11
Dependent Claim
98 words
A device as claimed in claim 3 or claim 8, or any one of claims 4 to 7 when read as appended to claim 3, wherein the word line selection level switching circuit comprises a transistor having a collector connected to a first power supply line, an emitter connected in common to the current source, which current source is connected between the emitter and a second power supply line, and to the rectifying circuits, and a base connected to receive a control signal which is relatively high in a write operation and relatively low in a read operation.
Claim 12
Dependent Claim
79 words
A device as claimed in claim 3 or claim 8 when read as appended to claim 2, or as claimed in any one of claims 4 to 7 when read as appended to claims 3 and 2, wherein the current provided by the current source flows in the load of a selected word driver in a read operation, whilst a current larger than the current provided by the current source flows in the load of a non-selected word driver.
Claim 13
Dependent Claim
178 words
A device as claimed in claim 1 or 2, or any one of claims 4 to 7 read as appended to claim 1 or 2, wherein the word line selection level switching circuit comprises a first transistor having a collector connected to a first power supply line, an emitter connected via a first resistor to a collector of a second transistor and to a base of a third transistor, a second resistor connected between the first power supply line and a base of the second transistor, and a diode connected between the base of the second transistor and a second power supply line, the emitter of the second transistor being connected to the second power supply line, the emitter of the third transistor being connected to the second power supply line via a third resistor, the collector of the third transistor being connected in common to the switching parts, and the base of the first transistor being connected to receive a control signal which is relatively high in a read operation and relatively low in a write operation.
References Cited (Backward Citations)
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