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US 8,570,199 B2Granted
Digital to analog converter circuits and methods
AssigneeMarvell World Trade Ltd.
InventorSasan Cyrusian
Life of this patent
Estimating the term…
Abstract
The present disclosure provides for improved DAC circuits and methods. In one embodiment, a digital-to-analog converter receives a digital signal and outputs a first analog output signal corresponding to the digital signal. A current buffer receives the first analog output signal and generates an analog output current. The current output digital-to-analog converter and the current buffer are constructed on an integrated circuit, and the analog output current is coupled to a pin of the integrated circuit. The pin of the integrated circuit receives the analog output current and provides the analog output current to additional circuitry external to the integrated circuit.
Claims24
A circuit, comprising:
- an integrated circuit including a pin configured to communicate with circuitry external to the integrated circuit;
- a current output digital-to-analog converter constructed on the integrated circuit, wherein the current output digital-to-analog converter is configured to i) receive a digital signal, ii) convert the digital signal to a first analog output current corresponding to the digital signal, and iii) convert the first analog output current to an analog voltage;
- a current buffer constructed on the integrated circuit, wherein the current buffer is configured to i) receive the analog voltage and ii) convert the analog voltage to a second analog output current,
- wherein the second analog output current is coupled to the pin of the integrated circuit, and wherein the pin is configured to i) receive the second analog output current and ii) output the second analog output current from the integrated circuit to the circuitry external to the integrated circuit.
1 more element
A circuit, comprising:
- a current output digital-to-analog converter, wherein the current output digital-to-analog converter is configured to i) receive a digital signal and ii) output a first analog output current corresponding to the digital signal;
- and
- a current buffer, wherein the current buffer is configured to i) receive the first analog output current and ii) generate a second analog output current,
- wherein the current output digital-to-analog converter and the current buffer are constructed on an integrated circuit, and wherein the second analog output current is coupled to a pin of the integrated circuit, and wherein the pin is configured to i) receive the second analog output current and ii) provide the second analog output current to circuitry external to the integrated circuit,
- and wherein the current buffer comprises
- an amplifier having a first input, second input, and an output, wherein an output of the current output digital-to-analog converter is coupled to the first input of the amplifier;
- a first resistor coupled between the output of the current output digital-to-analog converter and a power supply terminal;
- a second resistor coupled between the second input of the amplifier and the power supply terminal;
- and
- a transistor having a control terminal coupled to the output of the amplifier, a first terminal coupled to the second input of the amplifier, and a second terminal coupled to the pin of the integrated circuit.
7 more elements
A circuit, comprising:
- a current output digital-to-analog converter, wherein the current output digital-to-analog converter is configured to i) receive a digital signal and ii) output a first analog output current corresponding to the digital signal;
- and
- a current buffer, wherein the current buffer is configured to i) receive the first analog output current and ii) generate a second analog output current,
- wherein the current output digital-to-analog converter and the current buffer are constructed on an integrated circuit, and wherein the second analog output current is coupled to a pin of the integrated circuit, and wherein the pin is configured to i) receive the second analog output current and ii) provide the second analog output current to circuitry external to the integrated circuit,
- wherein the circuitry comprises
- a first external resistor coupled between the pin and ground;
- a transmission path having an input coupled to the pin;
- and
- a second external resistor coupled between an output of the transmission path and ground.
6 more elements
A method comprising:
- receiving a digital signal in a current output digital-to-analog converter, wherein the digital-to-analog converter is constructed on an integrated circuit;
- converting, on the integrated circuit, the digital signal to a first analog output current representation of the digital signal;
- converting, on the integrated circuit, the first analog output current to an analog voltage;
- converting, on the integrated circuit, the analog voltage to a second analog output current;
- and
- coupling the second analog output current to a pin of the integrated circuit, wherein the pin receives the second analog output current and provides the second analog output current to circuitry external to the integrated circuit.
3 more elements
A circuit, comprising:
- a current output digital-to-analog converter, the current output digital-to-analog converter receiving a digital signal and outputting a first analog output current corresponding to the digital signal;
- means for buffering the first analog output current and generating a second analog output current, wherein the current output digital-to-analog converter and said means for buffering are constructed on an integrated circuit, and wherein the second analog current signal is coupled to a pin of the integrated circuit, and wherein the pin receives the second analog current signal and provides the second analog current signal to circuitry external to the integrated circuit;
- and
- means for changing the offset of the second analog output current to control an offset at the pin.
1 more element
A circuit comprising:
- a digital-to-analog converter, the digital-to-analog converter receiving a digital signal and outputting a first analog output signal corresponding to the digital signal;
- a current buffer, wherein the current buffer receives the first analog output signal and generates an analog output current, wherein the digital-to-analog converter and the current buffer are constructed on an integrated circuit, and wherein the analog output current is coupled to a pin of the integrated circuit;
- and
- a double terminated transmission path external to the integrated circuit, the double terminated transmission path having near termination coupled to the pin and a far termination.
1 more element
Dependencies are inferred from the claim text.