Patent US4990916A successfully refreshed from Google Patents.
US4990916A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single-supply digital-to-analog converter for control function generation
Assignee: Analog Devices Inc
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Filing: 1990-01-30
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Granted: 1991-02-05
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Expires: 2010-01-30
Abstract
Abstract A converter for producing the function V out =V bias =V swing (1-2D), in which a DAC is combined with an operational amplifier and (typically) three or four resistors. A function of the voltage V swing , or a current corresponding thereto, is applied to the reference voltage input terminal of the DAC. The variable D is the DAC's digital input code, expressed as a decimal or fraction in the range between 0 and 1. The DAC output provides a suitably scaled and signed signal which is added to or subtracted from the offset signal V bias to produce V out .
Inventors
- 👤 John M. Wynne
- 👤 Michael Byrne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:42
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/66; G; G06; G06J; G06J1/00; H03M1/74; H03M1/78; H03M1/785
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
211 words
A circuit for producing the function V out = V bias + V swing (1-2D), where D represents the decimal or fractional equivalent of a digital code and may range in value between zero and one, and V bias and V swing are input variables, the circuit comprising: a. a digital-to analog converter (DAC) having a reference voltage input, an analog ground terminal, a digital input port for receiving said digital code, and an analog output terminal; b. an operational amplifier having inverting and non-inverting inputs and an output; c. the DAC output being provided to the non inverting input of the operational amplifier through a resistor of resistance R; d. the non inverting input of the operational amplifier also being connected to one lead of a resistor of resistance 2R, the other lead of said resistor being connected to receive the input voltage V bias ; e. means for supplying a voltage V swing /2 to the inverting input of the operational amplifier through an incremental resistance R; f. the output of the operational amplifier being connected to the inverting input of the operational amplifier through a resistor of resistance 2R; and g. the reference voltage input of the DAC being connected to receive the input voltage V swing .
Claim 2
Dependent Claim
211 words
A circuit for producing the function V out = V bias + V swing (1-2D), where D represents the decimal or fractional equivalent of a digital code and may range in value between zero and one, and V bias and V swing are input variables, the circuit comprising: a. a digital-to analog converter (DAC) having a reference voltage input, an analog ground terminal, a digital input port for receiving said digital code, and an analog output terminal; b. an operational amplifier having inverting and non-inverting inputs and an output; c. the DAC output being provided to the non inverting input of the operational amplifier through a resistor of resistance R; d. the non inverting input of the operational amplifier also being connected to one lead of a resistor of resistance 2R, the other lead of said resistor being connected to receive the input voltage V bias ; e. means for supplying a voltage V swing /2 to the inverting input of the operational amplifier through an incremental resistance R; f. the output of the operational amplifier being connected to the inverting input of the operational amplifier through a resistor of resistance 2R; and g. the reference voltage input of the DAC being connected to receive the input voltage V swing .
Claim 3
Dependent Claim
213 words
A circuit for producing the function V out = V bias ± V swing (1-2D), where D represents the decimal or fractional equivalent of a digital code and may range in value between zero and one, and V bias and V swing are input variables, the circuit comprising: a. an MOS digital to analog converter (DAC) having a reference voltage terminal, a digital input port for receiving said digital code, a first output terminal for supplying a first analog output current, and a second output terminal for supplying a second analog output current; b. an operational amplifier having inverting and non-inverting inputs and an output; c. the second DAC output being connected to the non inverting input of the operational amplifier; d. the non-inverting input of the operational amplifier also being connected to one lead of a resistor of resistance R m , the other lead of said resistor being connected to receive the input voltage V bias ; e. the inverting input of the operational amplifier being connected to the first output of the DAC and to the output of the operational amplifier through a resistor of resistance R m ; and f. means connected to the reference voltage terminal of the DAC a current equal to V swing /R m .
Claim 4
Dependent Claim
213 words
A circuit for producing the function V out = V bias ± V swing (1-2D), where D represents the decimal or fractional equivalent of a digital code and may range in value between zero and one, and V bias and V swing are input variables, the circuit comprising: a. an MOS digital to analog converter (DAC) having a reference voltage terminal, a digital input port for receiving said digital code, a first output terminal for supplying a first analog output current, and a second output terminal for supplying a second analog output current; b. an operational amplifier having inverting and non-inverting inputs and an output; c. the second DAC output being connected to the non inverting input of the operational amplifier; d. the non-inverting input of the operational amplifier also being connected to one lead of a resistor of resistance R m , the other lead of said resistor being connected to receive the input voltage V bias ; e. the inverting input of the operational amplifier being connected to the first output of the DAC and to the output of the operational amplifier through a resistor of resistance R m ; and f. means connected to the reference voltage terminal of the DAC a current equal to V swing /R m .
Claim 5
Dependent Claim
289 words
A circuit for producing the function V out = V bias + V swing (1-2D), where D represents the decimal or fractional equivalent of a digital code and may range in value between zero and one, and V bias and V swing are input variables, the circuit comprising: a. a digital to analog converter (DAC) having a reference voltage terminal, a digital input port for receiving said digital code, a first output terminal for supplying a first analog output current, and a second output terminal for supplying a second analog output current; b. an operational amplifier having inverting and non inverting inputs and an output; c. the second DAC output being connected to the non inverting input of the operational amplifier; d. the non inverting input of the operational amplifier also being connected to one lead of a resistor of resistance R m , the other lead of said resistor being connected to receive the input voltage V bias ; e. the inverting input of the operational amplifier being connected to the first output of the DAC and to the output of the operational amplifier through a resistor of resistance R m ; f. the DAC comprising an R-2R resistive ladder, a drive transistor in series with each 2R resistor in the ladder and, for each leg of the 2R resistors, a switch responsive to the digital code to connect the series transistor collector current to the appropriate one of the first and second DAC outputs, and a reference transistor connected to the last R resistor in the ladder; and g. means connected to the reference transistor to cause the current through the last R resistor in the ladder to be substantially equal to V swing /R m .
Claim 6
Dependent Claim
289 words
A circuit for producing the function V out = V bias + V swing (1-2D), where D represents the decimal or fractional equivalent of a digital code and may range in value between zero and one, and V bias and V swing are input variables, the circuit comprising: a. a digital to analog converter (DAC) having a reference voltage terminal, a digital input port for receiving said digital code, a first output terminal for supplying a first analog output current, and a second output terminal for supplying a second analog output current; b. an operational amplifier having inverting and non inverting inputs and an output; c. the second DAC output being connected to the non inverting input of the operational amplifier; d. the non inverting input of the operational amplifier also being connected to one lead of a resistor of resistance R m , the other lead of said resistor being connected to receive the input voltage V bias ; e. the inverting input of the operational amplifier being connected to the first output of the DAC and to the output of the operational amplifier through a resistor of resistance R m ; f. the DAC comprising an R-2R resistive ladder, a drive transistor in series with each 2R resistor in the ladder and, for each leg of the 2R resistors, a switch responsive to the digital code to connect the series transistor collector current to the appropriate one of the first and second DAC outputs, and a reference transistor connected to the last R resistor in the ladder; and g. means connected to the reference transistor to cause the current through the last R resistor in the ladder to be substantially equal to V swing /R m .
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) | 1994-02-04 | 1994-08-06 | 1995-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-04 | 1998-08-06 | 1999-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-04 | 2002-08-06 | 2003-02-05 | $7700.00 | Window Closed / Lapsed |