Current output type digital-to-analog converter capable of suppressing output current fluctuation using a current mirror
First Claim
1. A digital-to-analog converter comprising:
- a plurality of input terminals;
an output terminal;
a plurality of input signal lines connected to said input terminals, respectively;
a plurality of output signal lines;
a logic circuit including a plurality of MOS transistors each having a gate connected to one of said input signal lines, a drain connected to a first power supply terminal and a source which has one of a connection state where said source which has one of a connection state where said source is connected to one of said output signal lines and a disconnection state where said source is not connected to said output signal lines;
a reference current source including a constant current source and a first transistor connected to said constant current source;
a digital-to-analog conversion section including a plurality of second transistors each connected to one of said output signal lines and to said first transistor, each of said second transistors forming a current mirror circuit with said first transistor, and a plurality of third transistors each connected between said output terminal and one of said output signals lines, said first, second and third transistors being bipolar transistors.
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Accused Products
Abstract
In a digital-to-analog converter, a logic circuit includes a plurality of MOS transistors each having a gate connected to one of input signal lines, a drain connected to a first power supply terminal and a source which has one of a connection state where the source is connected to one of output signal lines and a disconnection state where the source is not connected to the output signal lines. A reference current source includes a constant current source and a first transistor connected in series. A digital-to-analog conversion section includes a plurality of second transistors each connected to one of the output signal lines and to the first transistor. Each of the second transistors forming a current mirror circuit with the first transistor. The digital-to-analog conversion section also includes a plurality of third transistors each connected between an output terminal and one of the output signal lines.
5 Citations
2 Claims
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1. A digital-to-analog converter comprising:
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a plurality of input terminals; an output terminal; a plurality of input signal lines connected to said input terminals, respectively; a plurality of output signal lines; a logic circuit including a plurality of MOS transistors each having a gate connected to one of said input signal lines, a drain connected to a first power supply terminal and a source which has one of a connection state where said source which has one of a connection state where said source is connected to one of said output signal lines and a disconnection state where said source is not connected to said output signal lines; a reference current source including a constant current source and a first transistor connected to said constant current source; a digital-to-analog conversion section including a plurality of second transistors each connected to one of said output signal lines and to said first transistor, each of said second transistors forming a current mirror circuit with said first transistor, and a plurality of third transistors each connected between said output terminal and one of said output signals lines, said first, second and third transistors being bipolar transistors. - View Dependent Claims (2)
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Specification
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- Resources
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Current AssigneeNEC Electronics Corporation (Renesas Electronics Corporation)
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Original AssigneeNEC Corporation
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InventorsHirasawa, Shinichi
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Primary Examiner(s)Young, Brian
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Assistant Examiner(s)Wamsley, Patrick
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Application NumberUS08/969,349Time in Patent Office921 DaysField of Search323/313, 323/315, 341/144, 341/120, 341/145, 341/153, 341/135, 341/118US Class Current341/144CPC Class CodesH03M 1/745 with weighted currents
