Patent EP0113216A2 successfully refreshed from Google Patents.
EP0113216A2
Expired / Lapsed
EP
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Digital analog converter
Assignee: Fujitsu Ltd
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Filing: 1983-12-13
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Granted: —
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Expires: 2003-12-13
Abstract
Abstract Switching circuits (15; I 1 ; 2R; 1 2 ,2R; etc) are connected to respective branch points, of an IC D/A converter, constituted by an output terminal (V out ) of the converter and connection points between series connected first resistors (R) and a second, terminating resistor (2R). At least one switching circuit (15), for example dealing with the most significant bit (A o ) of a digital signal input, has a configuration in which the relevant branch point (0') is supplied from a first voltage supply level (V REF ) and from a second voltage supply level (ground) respectively through different resistors (2R', 2R"), in dependence upon the value of the most significant bit. The different resistors have slightly different nominal resistance values so as to compensate for the effects of substrate bias voltage.
Inventors
- 👤 Youzi C/O Fujitsu Limited Hino
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 01:35
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/66; H03M1/74; H03M1/78; H03M1/785; H03M1/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
158 words
A digital-analog converter, comprising a resistance network having at least one first resistor connected, connected in series when more than one first resistor is provided, between an output terminal of the inverter and a second, terminating, resistor, the output terminal and the or each connecting point between those resistors constituting respective branch points of the network, a plurality of switching circuits, connected to respective branch points, operable to supply respective branch points from a first supply voltage level, or from a second supply voltage level, in dependence upon the values (1 or 0) of respective bits of a digital signal input to the converter, wherein at least one of the switching circuits has a configuration including third and fourth resistors and operable such that the branch point connected to the switching circuit concerned is supplied from the first supply voltage level through the third resistor and is supplied from the second supply voltage level through the fourth resistor.
Claim 2
Dependent Claim
158 words
A digital-analog converter, comprising a resistance network having at least one first resistor connected, connected in series when more than one first resistor is provided, between an output terminal of the inverter and a second, terminating, resistor, the output terminal and the or each connecting point between those resistors constituting respective branch points of the network, a plurality of switching circuits, connected to respective branch points, operable to supply respective branch points from a first supply voltage level, or from a second supply voltage level, in dependence upon the values (1 or 0) of respective bits of a digital signal input to the converter, wherein at least one of the switching circuits has a configuration including third and fourth resistors and operable such that the branch point connected to the switching circuit concerned is supplied from the first supply voltage level through the third resistor and is supplied from the second supply voltage level through the fourth resistor.
Claim 3
Dependent Claim
55 words
A converter as claimed in claim 1, wherein the said one of the switching circuits is operable to supply the branch point connected thereto, from the first supply voltage level or from the second supply voltage level, in dependence upon the value of the most significant bit of the digital signal input to the converter.
Claim 4
Dependent Claim
18 words
A converter as claimed in claim 2, wherein each switching circuit of the plurality has the said configuraton.
Claim 5
Dependent Claim
43 words
A converter as claimed in claim 1, wherein switching circuits of the plurality connected to branch points corresponding to the output terminal and to one or more of said connecting points neighboring the output terminal in the resistance network have the said configuration.
Claim 6
Dependent Claim
81 words
A converter as claimed in any one of claims 1 to 4, wherein the nominal resistance of the or each third resistor differs slightly from the nominal resistance of the or each forth resistor, both those resistances being close to twice the resistance of the or each first resistor, and the terminating resistor having the same resistance as the or a third resistor or as the or a fourth resistor, or a resistance twice that of the or a first resistor.
Claim 7
Dependent Claim
106 words
A converter as claimed in any preceding claim, wherein the said configuration further includes a p-channel MOS transistor and an n-channel MOS transistor, the gates of the MOS transistors being connected in common to receive a bit of the digital signal input to the converter, the source of the p-channel MOS transistor being connected for receiving the first supply voltage level, the drain of the p-channel MOS transistor being connected to the relevant branch point, the source of the n-channel MOS transistor being connected to the relevant branch point, and the drain of the n-channel MOS transistor being connected for receiving the second supply voltage level.
Claim 8
Dependent Claim
27 words
A converter as claimed in claim 6, wherein the resistors are constituted by p or n-type conductive semiconductor channels embedded in semiconductor material of opposite conductivity type.
Claim 9
Dependent Claim
85 words
A converter as claimed in claim 7, wherein the first supply voltage level is a positive level and the second supply voltage level is ground, and wherein if the resistors are p-type conductive channels, the nominal resistances of the third and fourth resistors are respectively lesser and greater than the resistance of the terminating resistor, and wherein if the resistors are n-type conductive channels, the nominal resistances of the third and fourth resistors are respectively greater and lesser than the resistance of the terminating resistor.
Claim 10
Dependent Claim
25 words
A converter as claimed in claim 7 or 8, wherein the resistor channels are each strip-shaped and are layed out in parallel to one another.
Claim 11
Dependent Claim
30 words
A converter as claimed in any one of claims 6 to 9, wherein all resistors are provided from two basic resistor types, corresponding to the third and fourth resistors respectively.
References Cited (Backward Citations)
No citation records indexed.
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