Patent JPS5614837A successfully refreshed from Google Patents.
US5483150A
Expired / Lapsed
US
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Transistor current switch array for digital-to-analog converter (DAC) including bias current compensation for individual transistor current gain and thermally induced base-emitter voltage drop variation
Assignee: Microelectronics Technology Inc
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Filing: 1993-02-05
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Granted: 1996-01-09
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Expires: 2013-02-05
Abstract
Abstract A bias voltage source (20) produces a variable bias voltage (VBREF) which regulates the bias currents in an array (30) of transistor current switch cells (34,36) in an digital-to-analog converter (DAC). The bias voltage (VBREF) is applied to the bases of the regulating transistors (Q8') in the cells (34,36) to regulate the bias currents in their respective main transistors (Q6',Q7') to values proportional to the main bias current (IBIAS). Each main transistor (Q6,Q6',Q7,Q7') and regulating transistor (Q8,Q8') is provided with a compensating transistor (Q10,Q10')(Q11,-Q11') which sinks the emitter-base current thereof and cancels deviation of the actual current gain from the design current gain. Another compensating transistor (Q9,Q9') is connected to each regulating transistor (Q8,Q8') to cancel the effect of base-emitter voltage variation with temperature.
Inventors
- 👤 Phillip L. Elliott
- 👤 Dwight D. Birdsall
- 👤 Lloyd F. Linder
- 👤 Kelvin T. Tran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:52
CPC Classifications
G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/205; H; H03; H03M; H03M1/00; H03M1/06; H03M1/08; H03M1/089; H03M1/66; H03M1/74; H03M1/742
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
111 words
A transistor bias voltage source, comprising: a main transistor having a predetermined design current gain; reference voltage means for producing a predetermined reference voltage which causes a main bias current to flow through the main transistor; a regulating transistor for regulating said main bias current; feedback amplifier means for sensing said main bias current and generating a variable bias voltage which causes the regulating transistor to regulate said main bias current to a predetermined value; and compensation means for substantially canceling at least one of a deviation of the actual current gain of the main transistor from said design current gain and a thermally variable voltage drop in the regulating transistor.
Claim 2
Dependent Claim
111 words
A transistor bias voltage source, comprising: a main transistor having a predetermined design current gain; reference voltage means for producing a predetermined reference voltage which causes a main bias current to flow through the main transistor; a regulating transistor for regulating said main bias current; feedback amplifier means for sensing said main bias current and generating a variable bias voltage which causes the regulating transistor to regulate said main bias current to a predetermined value; and compensation means for substantially canceling at least one of a deviation of the actual current gain of the main transistor from said design current gain and a thermally variable voltage drop in the regulating transistor.
Claim 3
Dependent Claim
53 words
A bias voltage source as in claim 1, in which: the main transistor is a bipolar transistor including an emitter, a base and a collector; and the compensation means comprises a compensating element connected to the emitter of the main transistor for causing the base-emitter current of the main transistor to flow therethrough.
Claim 4
Dependent Claim
86 words
A bias voltage source as in claim 2, in which: the compensating element comprises a bipolar transistor which includes an emitter, a base and a collector and has the same predetermined design current gain as the main transistor; the base of the compensating transistor is connected to the emitter of the main transistor; and the compensation means further comprises current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the compensating transistor.
Claim 5
Dependent Claim
46 words
A bias voltage source as in claim 1, in which: the regulating transistor has a predetermined design current gain; and the compensation means further comprises means for substantially canceling a deviation of the actual current gain of the regulating transistor from said design current gain thereof.
Claim 6
Dependent Claim
53 words
A bias voltage source as in claim 4, in which: the regulating transistor is a bipolar transistor including an emitter, a base and a collector; and the compensation means comprises a compensating element connected to the emitter of the regulating transistor for causing the emitter-base current of the regulating transistor to flow therethrough.
Claim 7
Dependent Claim
86 words
A bias voltage source as in claim 5, in which: the compensating element comprises a compensating transistor which includes an emitter, a base and a collector and has the same predetermined design current gain as the regulating transistor; the base of the compensating transistor is connected to the emitter of the regulating transistor; and the compensation means further comprises current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the compensating transistor.
Claim 8
Dependent Claim
96 words
A bias voltage source as in claim 1, in which: the regulating transistor is a bipolar transistor including an emitter, a base and a collector; said thermally variable voltage drop is a base-emitter voltage drop of the regulating transistor; the amplifier means comprises an output for producing said bias voltage; and the compensation means comprises a compensating element which is connected between the output of the amplifier means and the base of the regulating transistor and has a thermally variable compensating voltage drop which is substantially equal to said base-emitter voltage drop of the regulating transistor.
Claim 9
Dependent Claim
67 words
A bias voltage source as in claim 7, further comprising: current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the compensating element; and current sink means for sinking said compensation bias current from the output of the amplifier means such that substantially no current flows through the output of the amplifier means.
Claim 10
Dependent Claim
34 words
A bias voltage source as in claim 7, in which: the compensating element comprises a diode-connected compensating transistor; and said thermally variable compensating voltage drop is a base-emitter voltage drop of the compensating transistor.
Claim 11
Dependent Claim
42 words
A bias voltage source as in claim 9, in which: the compensation means further comprises current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the compensating transistor.
Claim 12
Dependent Claim
39 words
A bias voltage source as in claim 10, further comprising current sink means for sinking said compensation bias current from the output of the amplifier means such that substantially no current flows through the output of the amplifier means.
Claim 13
Dependent Claim
212 words
A transistor cell array, comprising: a bias voltage source, including: a source main transistor having a predetermined design current gain; reference voltage means for producing a predetermined reference voltage which causes a main bias current to flow through the source main transistor; a source regulating transistor for regulating said main bias current; feedback amplifier means for sensing said main bias current and generating a variable bias voltage which causes the source regulating transistor to regulate said main bias current to a predetermined value; and source compensation means for substantially canceling at least one of a deviation of the actual current gain of the source main transistor from said design current gain and a thermally variable voltage drop in the source regulating transistor; and a plurality of transistor cells, each including: a cell main transistor which is substantially identical to the source main transistor; a cell regulating transistor which is substantially identical to the source regulating transistor for regulating bias current flow through the cell main transistor to a value corresponding said bias voltage; and cell compensation means for substantially canceling at least one of a deviation of the actual current gain of the cell main transistor from said design current gain and a thermally variable voltage drop in the cell regulating transistor.
Claim 14
Dependent Claim
212 words
A transistor cell array, comprising: a bias voltage source, including: a source main transistor having a predetermined design current gain; reference voltage means for producing a predetermined reference voltage which causes a main bias current to flow through the source main transistor; a source regulating transistor for regulating said main bias current; feedback amplifier means for sensing said main bias current and generating a variable bias voltage which causes the source regulating transistor to regulate said main bias current to a predetermined value; and source compensation means for substantially canceling at least one of a deviation of the actual current gain of the source main transistor from said design current gain and a thermally variable voltage drop in the source regulating transistor; and a plurality of transistor cells, each including: a cell main transistor which is substantially identical to the source main transistor; a cell regulating transistor which is substantially identical to the source regulating transistor for regulating bias current flow through the cell main transistor to a value corresponding said bias voltage; and cell compensation means for substantially canceling at least one of a deviation of the actual current gain of the cell main transistor from said design current gain and a thermally variable voltage drop in the cell regulating transistor.
Claim 15
Dependent Claim
104 words
An array as in claim 12, in which: the source main transistor is a bipolar transistor including an emitter, a base and a collector; and the source compensation means comprises a source compensating element connected to the emitter of the source main transistor for causing the emitter-base current of the source main transistor to flow therethrough; each cell main transistor is a bipolar transistor including an emitter, a base and a collector; and each cell compensation means comprises a cell compensating element connected to the emitter of the cell main transistor for causing the emitter-base current of the cell main transistor to flow therethrough.
Claim 16
Dependent Claim
170 words
An array as in claim 13, in which: the source compensating element comprises a bipolar transistor which includes an emitter, a base and a collector and has the same predetermined design current gain as the source main transistor; the base of the source compensating transistor is connected to the emitter of the source main transistor; the compensation means further comprises current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the source compensating transistor; each cell compensating element comprises a bipolar transistor which includes an emitter, a base and a collector and has the same predetermined design current gain as the cell main transistor; the base of the cell compensating transistor is connected to the emitter of the cell main transistor; and the cell compensation means further comprises current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the cell compensating transistor.
Claim 17
Dependent Claim
85 words
An array as in claim 12, in which: the source regulating transistor has a predetermined design current gain; the source compensation means further comprises means for substantially canceling a deviation of the actual current gain of the source regulating transistor from said design current gain thereof; each cell regulating transistor has a predetermined design current gain; and each cell compensation means further comprises means for substantially canceling a deviation of the actual current gain of the cell regulating transistor from said design current gain thereof.
Claim 18
Dependent Claim
101 words
An array as in claim 15, in which: the source regulating transistor is a bipolar transistor including an emitter, a base and a collector; the source compensation means comprises a compensating element connected to the emitter of the source regulating transistor for causing the emitter-base current of the source regulating transistor to flow therethrough; each cell regulating transistor is a bipolar transistor including an emitter, a base and a collector; and each cell compensation means comprises a compensating element connected to the emitter of the cell regulating transistor for causing the emitter-base current of the cell regulating transistor to flow therethrough.
Claim 19
Dependent Claim
172 words
An array as in claim 16, in which: the source compensating element comprises a source compensating transistor which includes an emitter, a base and a collector and has the same design current gain as the source regulating transistor; the base of the source compensating transistor is connected to the emitter of the source regulating transistor; and the source compensation means further comprises current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the source compensating transistor; each cell compensating element comprises a cell compensating transistor which includes an emitter, a base and a collector and has the same design current gain as the cell regulating transistor; the base of the cell compensating transistor is connected to the emitter of the cell regulating transistor; and the cell compensation means further comprises current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the cell compensating transistor.
Claim 20
Dependent Claim
182 words
An array as in claim 12, in which: the source regulating transistor is a bipolar transistor including an emitter, a base and a collector; said thermally variable voltage drop of the source regulating transistor is a base-emitter voltage drop thereof; the amplifier means comprises an output for producing said bias voltage; the source compensation means comprises a source compensating element which is connected between the output of the amplifier means and the base of the source regulating transistor and has a thermally variable compensating voltage drop which is substantially equal to said base-emitter voltage drop of the source regulating transistor; each cell regulating transistor is a bipolar transistor including an emitter, a base and a collector; said thermally variable voltage drop of each cell regulating transistor is a base-emitter voltage drop thereof; and each cell compensation means comprises a cell compensating element which is connected between the output of the amplifier means and the base of the cell regulating transistor and has a thermally variable compensating voltage drop which is substantially equal to said base-emitter voltage drop of the cell regulating transistor.
Claim 21
Dependent Claim
94 words
An array as in claim 18, further comprising: current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the source compensating element; current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through each cell compensating element; and current sink means for sinking said compensation bias currents from the output of the amplifier means such that substantially no current flows through the output of the amplifier means.
Claim 22
Dependent Claim
63 words
An array as in claim 18, in which: the source compensating element comprises a diode-connected source compensating transistor; said thermally variable compensating voltage drop of the source compensating transistor is a base-emitter voltage drop thereof; each cell compensating element comprises a diode-connected cell compensating transistor; and said thermally variable compensating voltage drop of the cell compensating transistor is a base-emitter voltage drop thereof.
Claim 23
Dependent Claim
77 words
An array as in claim 20, in which: the source compensation means further comprises current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the source compensating transistor; and each cell compensation means further comprises current source means for causing a compensation bias current which is substantially equal to said predetermined value of main bias current to flow through the cell compensating transistor.
Claim 24
Dependent Claim
37 words
An array as in claim 21, further comprising current sink means for sinking said compensation bias currents from the output of the amplifier means such that substantially no current flows through the output of the amplifier means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-01-08 | 1999-07-10 | 2000-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-08 | 2003-07-10 | 2004-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-08 | 2007-07-10 | 2008-01-09 | $7700.00 | Window Closed / Lapsed |