Invalidity dossier
US 5619203
Current source driven converter
Current assignee: Avago Technologies International Sales Pte Ltd
Added 9/23/2026, 12:07:03 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US 5,619,203 A — "Current Source Driven Converter"
Patent number: US 5,619,203 A
Title: Current source driven converter
Application number: US 08/327,162
Priority/filing date: 1994-10-21
Publication (grant) date: 1997-04-08
Original assignee: Lucent Technologies Inc. (earlier assignment to AT&T Corp.; later AT&T IPM Corp. and Lucent Technologies Inc. per the record)
Inventors: George F. Gross, Jr.; Thayamkulangara R. Viswanathan
Classification: H03M 1/66, 1/74, 1/76, 1/765
Status listed: Expired – Lifetime (anticipated expiration 2014-10-21)
Purpose. The invention relates generally to digital-to-analog converters (DACs), particularly ones driven by a current source. A stated problem is that in voltage-driven resistor-string DACs, noise voltage in series with the reference voltage source changes the voltage across each resistor and thus at each intermediate tap, producing an erroneous analog output.
Plain-language scope. An integrated circuit includes a DAC in which a resistor string is driven by a current source. Intermediate taps are defined at resistor junctions and at the resistor–current-source junctions. Switching transistors (shown as MOS transistors) couple between a common output node and respective intermediate taps, controlled by a selection/driver circuit responsive to a digitally encoded signal. Because the current source has high impedance, noise voltage induced in the current-source–resistor-string loop does not alter the current, so the output voltage depends only on that current and the resistor values. The illustrative embodiments cover a single-ended mode (FIG. 1), a differential mode with sample-and-hold capacitors and a differential amplifier (FIG. 2), a differential version achieving an additional bit with the same resistors and switches (FIG. 3), and an analog-to-digital converter incorporating such a DAC (FIG. 4). Voltages intermediate the tap voltages may be obtained by switching on multiple transistors. The text states the DAC is suitable for monolithic integrated-circuit fabrication.
Source: https://patents.google.com/patent/US5619203/en
What the excerpt does not establish. The supplied excerpt omits the claims, full detailed description, and prior-art discussion. It therefore does not establish claim scope, claim count, or the specific references relied upon; nor does it verify the machine-generated assignee/reassignment history or legal status.
Generated 10/1/2026, 9:53:49 PM
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Assignment history
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Prior art
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