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US 5,327,134 AGranted
D-A converter
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsYasuyuki Nakamura, Toshio Kumamoto
Life of this patent
Estimating the term…
Abstract
In order to improve linearlity of analog current outputs with respect to input digital codes in a D-A converter formed by a matrix array of unit current sources, respective current source cells forming the matrix are connected by analog ground wires (101 to 105 ) along respective rows. Analog ground wires (301, 302 ) connect left sides of the analog ground wires (102, 104) and right sides of the analog ground wires (101, 103, 105) to pads (41, 42 ) respectively, to ground the same. Thus, large-small relations of current distributions are reversed in respective rows, whereby influences by the current distributions are cancelled.
Claims45
A D-A converter comprising:
- (a) a plurality of complementary output cells being arranged in the form of a matrix, each said complementary output cell having:
- (a-1) a changeover switch having a common terminal and first and second terminals, and
- (a-2) a unit current source having a first end being connected to said common terminal and a second end;
- (b) a plurality of first analog lines connecting prescribed ones of said second ends of said unit current sources in common;
- (c) a pair of second analog lines connecting prescribed ones of said first analog lines to fixed potentials in common;
- (d) first and second output current terminals being connected to all said first and second terminals of said changeover switches respectively;
- and
- (e) a decoder receiving a digital signal and generating a control signal for controlling switching of said changeover switches on the basis of said digital signal and successively working said complementary output cells one by one with increase of a value indicated by said digital signal,
- (b-1) each said first analog lines connecting all said second ends of said unit current sources of said complementary output cells being row-directionally arranged in each row,
- (b-2) adjacent ones of said first analog lines being connected to different ones of said second analog lines,
- (c-1) said pair of second analog lines extending on the opposite side of said complementary output cells in different directions being substantially parallel to the column direction.
8 more elements
A D-A converter comprising:
- (a) a plurality of complementary output cells being arranged in the form of a matrix, each said complementary output cell having:
- (a-1) a changeover switch having a common terminal and first and second terminals, and
- (a-2) a unit current source having a first end being connected to said common terminal and a second end;
- (b) a plurality of first analog lines-connecting prescribed ones of said second ends of said unit current sources in common;
- (c) a pair of second analog lines connecting prescribed ones of said first analog lines to fixed potentials in common;
- (d) first and second output current terminals being connected to all said first and second terminals of said changeover switches respectively;
- and
- (e) a decoder receiving a digital signal and generating a control signal for controlling switching of said changeover switches on the basis of said digital signal and successively working said complementary output cells one by one with increase of a value indicated by said digital signal,
- (b-1) each said first analog lines connecting all said second ends of said unit current sources of said complementary output cells being column-directionally arranged in each column,
- (b-2) adjacent ones of said first analog lines being connected to different ones of said second analog lines,
- (c-1) said pair of second analog lines extending on the opposite side of said complementary output cells in different directions being substantially parallel to the row direction.
8 more elements
A D-A converter comprising:
- (a) a plurality of complementary output cells being arranged in the form of a matrix, each said complementary output cell having:
- (a-1) a changeover switch having a common terminal and first and second terminals, and
- (a-2) a unit current source having a first end being connected to said common terminal and a second end;
- (b) a plurality of first and second analog lines connecting prescribed ones of said second ends of said unit current sources in common;
- (c) a pair of third analog lines connecting prescribed ones of said first analog lines to fixed potentials in common and a pair of fourth analog lines connecting prescribed ones of said second analog lines to fixed potentials in common;
- (d) first and second output current terminals being connected to all said first and second terminals of said changeover switches respectively;
- and
- (e) a decoder receiving a digital signal and generating a control signal for controlling switching of said changeover switches on the basis of said digital signal and successively working said complementary output cells one by one with increase of a value indicated by said digital signal,
- said first analog lines
- (b-1) connecting all said second ends of said unit current sources of said complementary output cells belonging to odd columns in common in each odd row, while
- (b-2) connecting all said second ends of said unit current sources of said complementary output cells belonging to even columns in common in each even row,
- said second analog lines
- (b-3) connecting all said second ends of said unit current sources of said complementary output cells belonging to even rows in common in each odd column, while
- (b-4) connecting all said second ends of said unit current sources of said complementary output cells belonging to odd rows in common in each even column,
- (c-1) adjacent ones of said first analog lines being connected to different ones of said third analog lines,
- (c-2) said pair of third analog lines extending on the opposite side of said complementary output cells in different directions substantially parallel to the column direction,
- (c-3) adjacent ones of said second analog lines being connected to different ones of said fourth analog lines,
- (c-4) said pair of fourth analog lines extending on the opposite side of said complementary output cells in different directions substantially parallel to the row direction.
15 more elements
Dependencies are inferred from the claim text.