US5410186A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Programmable digital to analog converter
Assignee: International Business Machines Corp
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Filing: 1994-03-04
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Granted: 1995-04-25
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Expires: 2014-03-04
Abstract
Abstract By providing data to a selection switch via a multiplexor so it can be programmed to supply either a current programmably controlled by a shift register or a current fixed by a fused resistor. Selected signals coupled to the multiplexor control the selection of either the resistor or the shift register thus, providing an improved current selection device which is capable of automatically selecting and programming the current supplied to circuits such as digital to analog converters.
Inventors
- 👤 Anthony R. Bonaccio
- 👤 John E. Gersbach
- 👤 Christian J. Goetschel
- 👤 Sharon L. Von Bruns
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:35
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/66; H03M1/74; H03M1/742
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
126 words
A current setting digital to analog convertor circuit comprising: a plurality of output transistors coupled to a common output, a clock driven shift register having a plurality of outputs, a respective programmable current selection circuit coupled between each of said respective one of said pluralities of shift register outputs and said plurality of output transistors, characterized by each of said programmable current selection circuits comprising, a multiplexor having an output, a first input coupled to a voltage source, a second input coupled to said shift register and means for selecting between said first and second inputs, and selection switching means coupled to the output of said multiplexor, including a current source, to either selectively turn on or turn off a respective one of said output transistors.
Claim 2
Dependent Claim
126 words
A current setting digital to analog convertor circuit comprising: a plurality of output transistors coupled to a common output, a clock driven shift register having a plurality of outputs, a respective programmable current selection circuit coupled between each of said respective one of said pluralities of shift register outputs and said plurality of output transistors, characterized by each of said programmable current selection circuits comprising, a multiplexor having an output, a first input coupled to a voltage source, a second input coupled to said shift register and means for selecting between said first and second inputs, and selection switching means coupled to the output of said multiplexor, including a current source, to either selectively turn on or turn off a respective one of said output transistors.
Claim 3
Dependent Claim
37 words
The circuit of claim 1 wherein each multiplexor can be selected to selectively couple either the second input coupled to the shift register or the first input coupled to the voltage sources to the selection switching means.
Claim 4
Dependent Claim
27 words
The circuit of claim 1 wherein said first input of said multiplexor is coupled to the voltage source through a fuse and to ground through a resistor.
Claim 5
Dependent Claim
27 words
The circuit of claim 1 wherein said first input of said multiplexor is coupled to the voltage source through a resistor and to ground through a fuse.
Claim 6
Dependent Claim
133 words
A current setting circuit having an output comprising: a shift register having a plurality of inputs and outputs, a clock coupled to a first input of said shift register for driving said shift register, a processor coupled to a second input of said shift register for controlling said shift register, a plurality of multiplexors, each multiplexor having an output, a pair of inputs, and means for selecting between said pair of inputs, and each multiplexor coupled to a respective output of said shift register, a plurality of switch selection circuits each having an output, and each switch selection circuit coupled to the output of a respective multiplexor, and a plurality of output transistors each coupled to the output of a respective switch selection circuit and to the output of the current setting circuit.
Claim 7
Dependent Claim
133 words
A current setting circuit having an output comprising: a shift register having a plurality of inputs and outputs, a clock coupled to a first input of said shift register for driving said shift register, a processor coupled to a second input of said shift register for controlling said shift register, a plurality of multiplexors, each multiplexor having an output, a pair of inputs, and means for selecting between said pair of inputs, and each multiplexor coupled to a respective output of said shift register, a plurality of switch selection circuits each having an output, and each switch selection circuit coupled to the output of a respective multiplexor, and a plurality of output transistors each coupled to the output of a respective switch selection circuit and to the output of the current setting circuit.
Claim 8
Dependent Claim
20 words
The circuit of claim 5 wherein said output transistors are bipolar transistors having an emitter, a base and a collector.
Claim 9
Dependent Claim
43 words
The circuit of claim 6 wherein all of said plurality of transistors have their emitters commonly coupled to ground, their collectors commonly coupled to the current setting circuit output and the base of each transistor is coupled to a respective switch selection circuit.
Claim 10
Dependent Claim
14 words
The circuit of claim 7 wherein each switch selection circuit includes a current source.
Claim 11
Dependent Claim
43 words
The circuit of claim 5 wherein in each said multiplexor, one of said pair of inputs is coupled to said shift register and the other of said inputs is coupled to a voltage source through a fuse and to ground through a resistor.
Claim 12
Dependent Claim
39 words
The circuit of claim 9 wherein said current setting circuit further includes a signal source coupled to each of said plurality of multiplexors for selectively coupling one of said inputs of said multiplexor to said output of said multiplexor.
Claim 13
Dependent Claim
15 words
The circuit of claim 10 wherein said signal source is a source providing complementary signals.
Claim 14
Dependent Claim
46 words
The circuit of claim 5 wherein said multiplexor includes a pair of inputs, one of said pair of inputs being coupled to said shift register and the other of said inputs being coupled to a voltage source through a resistor and to ground through a fuse.
Claim 15
Dependent Claim
134 words
A current setting digital to analog convertor circuit comprising: a plurality of output transistors coupled to a common output, a register having a plurality of outputs, a respective programmable current selection circuit coupled between each of said respective one of said pluralities of said register outputs and said plurality of output transistors, characterized by each of said programmable current selection circuits comprising, a multiplexor having an output, a first input coupled to ground and, through a first selection means, to a voltage source, a second input coupled to said shift register, and second selection means for selectively switching between said first and second inputs, and selection switching means coupled to the output of said multiplexor, including a current source, to either selectively turn on or turn off a respective one of said output transistors.
Claim 16
Dependent Claim
134 words
A current setting digital to analog convertor circuit comprising: a plurality of output transistors coupled to a common output, a register having a plurality of outputs, a respective programmable current selection circuit coupled between each of said respective one of said pluralities of said register outputs and said plurality of output transistors, characterized by each of said programmable current selection circuits comprising, a multiplexor having an output, a first input coupled to ground and, through a first selection means, to a voltage source, a second input coupled to said shift register, and second selection means for selectively switching between said first and second inputs, and selection switching means coupled to the output of said multiplexor, including a current source, to either selectively turn on or turn off a respective one of said output transistors.
Claim 17
Dependent Claim
155 words
A current setting circuit having an output comprising: a shift register having a plurality of inputs and outputs, a clock coupled to a first input of said shift register for driving said shift register, a processor coupled to a second input of said shift register for controlling said shift register, a plurality of multiplexors, each multiplexor having an output, a first and a second input, and means for selecting between said first and second input, said first input being coupled to means for selectively setting one of two distinct voltage levels thereon and said second input being coupled to a respective output of said shift register, a plurality of switch selection circuits each having an output, and each switch selection circuit coupled to the output of a respective multiplexor, and a plurality of output transistors each coupled to the output of a respective switch selection circuit and to the output of the current setting circuit.
Claim 18
Dependent Claim
155 words
A current setting circuit having an output comprising: a shift register having a plurality of inputs and outputs, a clock coupled to a first input of said shift register for driving said shift register, a processor coupled to a second input of said shift register for controlling said shift register, a plurality of multiplexors, each multiplexor having an output, a first and a second input, and means for selecting between said first and second input, said first input being coupled to means for selectively setting one of two distinct voltage levels thereon and said second input being coupled to a respective output of said shift register, a plurality of switch selection circuits each having an output, and each switch selection circuit coupled to the output of a respective multiplexor, and a plurality of output transistors each coupled to the output of a respective switch selection circuit and to the output of the current setting circuit.
Claim 19
Dependent Claim
28 words
The circuit of claim 14 wherein in each said multiplexor the first input is coupled to a voltage source through a fuse and to ground through a resistor.
Claim 20
Dependent Claim
38 words
The circuit of claim 15 wherein said current setting circuit further includes, in each of said plurality of multiplexors, a signal source for selectively coupling one of said inputs of said multiplexor to said output of said multiplexor.
Claim 21
Dependent Claim
15 words
The circuit of claim 16 wherein said signal source is a source supplying complementary signals.
Claim 22
Dependent Claim
40 words
The circuit of claim 14 wherein said means for selectively setting one of two distinct voltage levels thereon comprises a resistor coupled between said first input and a voltage source and a fuse coupled between said first input and ground.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-04-24 | 1998-10-24 | 1999-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-04-24 | 2002-10-24 | 2003-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-04-24 | 2006-10-24 | 2007-04-25 | $7700.00 | Window Closed / Lapsed |