EP0458659A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Semiconductor integrated circuit device for supplying a bias current to DA converters
Assignee: Fujitsu VLSI Ltd
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Filing: 1991-02-22
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Granted: —
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Expires: 2011-02-22
Abstract
Abstract A semiconductor integrated circuit device comprising a bias generating circuit having an operational amplifier connected to receive an input voltage at its inverting input terminal to produce a gate voltage, a field effect transistor having its gate connected to receive the gate voltage from said operational amplifier and its drain connected to a resistor and to a noniverting input terminal of said operational amplifier, and further field effect transistor having its gate connected to receive the gate voltage from said operational amplifier to produce a current corresponding to the input voltage, one group of current sources responsive to an output voltage of said bias generating circuit to produce a plurality of currents of an equal magnitude and one switching circuit responsive to an input digital value to selectively output the currents from said group of current sources to its common output.
Inventors
- 👤 Kunihiko Gotoh
- 👤 Yuuji Sekido
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 14:39
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/06; H03M1/0602; H03M1/0604; H03M1/66; G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/26; G05F3/262; H03M1/74; H03M1/662; H03M1/742
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
96 words
A semiconductor integrated circuit device comprising: - a bias generating circuit having means for producing a gate voltage, a first field effect transistor having its gate connected to receive the gate voltage from said producing means to produce a current - at least one group of current sources responsive to an output voltage of said bias generating circuit to produce a plurality of currents of an equal magnitude; and - at least one switching circuit responsive to an input digital value to selectively output the currents from said group of current sources to its common output.
Claim 2
Dependent Claim
31 words
The semiconductor integrated circuit device according to claim 1, in which said common output of said switching circuit is connected to a resistor adapted to convert a current to a voltage.
Claim 3
Dependent Claim
30 words
The semiconductor integrated circuit device according to claim 1, in which said bias generating circuit, said group of current sources and said switching circuit are formed on a semiconductor chip.
Claim 4
Dependent Claim
61 words
The semiconductor integrated circuit device according to claim 1, in which said switching circuit has as many switches as there are current sources in said current source group, each of said switches forming a pair with a respective one of said current sources and the number of pairs being smaller by one than the maximum value of an input digital value.
Claim 5
Dependent Claim
28 words
The semiconductor integrated circuit device according to claim 4, in which, in said switching circuit, switches corresponding in number to the input digital value are turned on simultaneously.
Claim 6
Dependent Claim
34 words
The semiconductor integrated circuit device according to claim 1, in which the input digital data are ON signals obtained by decoding input data of plural bits and correspond in number to the input data.
Claim 7
Dependent Claim
38 words
The semiconductor integrated circuit device according to claim 6, in which, when the input data has bit, the number of said switches and the number of said current sources each equal the ℓth power of 2 minus 1.
Claim 8
Dependent Claim
80 words
The semiconductor integrated circuit device according to claim 1, wherein - said producing means comprises an operational amplifier connected to receive an input voltage at its inverting input terminal and said first field effect transistor produces said current coresponding to the input voltage and further comprising a second field effect transistor having its gate connected to the gate voltage from said operational amplifier and its drain connected to a resistor and to a non-inverting input terminal of said operational amplifier.
Claim 9
Dependent Claim
26 words
The semiconductor integrated circuit device according to claim 8, wherein - said first and second field effect transistors have their sources connected to a power supply.
Claim 10
Dependent Claim
30 words
The semiconductor integrated circuit device according to claim 8, wherein - said bias generating circuit, said group of current sources and said switching circuit are formed on a semiconductor chip.
Claim 11
Dependent Claim
28 words
The semiconductor integrated circuit device according to claim 10, wherein - said first and second field effect transistors are formed close to each other on said semiconductor chip.
Claim 12
Dependent Claim
46 words
The semiconductor integrated circuit device according to claim 1, further comprising data conversion means responsive to digital data to produce the select signal, and load resistors connected to outputs of said current selecting and outputting circuits, whereby the digital data are converted to an analog voltage.
Claim 13
Dependent Claim
106 words
A semiconductor integrated circuit device comprising: - a number n of current selecting and outputting circuits each having m current sources and m switches responsive to a select signal for selectively outputting currents from said current sources; and - current bias generating means for supplying each of said current selecting and outputting circuits with a bias current, - said current selecting and outputting circuits being formed on a semiconductor chip, - said current bias generating means comprising bias voltage generating means responsive to an external control signal to generate a bias voltage and operation setting transistors responsive to said bias voltage to generate a bias current.
References Cited (Backward Citations)
No citation records indexed.
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