Return to open DAC with resistor bypass on reset
AssigneeNXP B.V.
InventorsSelcuk Ersoy, Dobson Paul Parlindungan Simanjuntak, Robert van Veldhoven
Life of this patent
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Abstract
An analog to digital circuit that includes a feedback circuit with a return to open (RTO), digital to analog converter (DAC) that provides an analog signal that is indicative of an output of an ADC component of the ADC. During a data phase, the output of the DAC is provided to a combiner input through a resistive circuit. The combiner also receives an analog input signal at another input and provides a combined output signal to the ADC component. During a reset phase, the output of the DAC is provided to the combiner through a lower resistance bypass circuit to bypass the resistive circuit.
Claims20
An analog to digital converter (ADC) comprising:
- an analog to digital converter (ADC) component;
- a combiner, including a first input coupled to receive an analog input signal, a second input, and an output, the output of the combiner is coupled to an input of the ADC component;
- a feedback circuit comprising:
- a digital to analog converter (DAC) including an input coupled to an output of the ADC component wherein the DAC is characterized as a return to open DAC wherein an output of the DAC is at a high impedance state during a reset phase;
- a resistive circuit including a first terminal coupled to the output of the DAC and a second terminal coupled to the second input of the combiner to provide a resistance between the output of the DAC and the second input of the combiner during a data phase;
- a reset bypass circuit that when enabled during the reset phase provides a bypass path to electrically short the output of the DAC to the second input of the combiner.
A method for converting an analog signal to a digital signal, the method comprising:
- in a data phase, producing by an output of a digital to analog converter (DAC) of a feedback circuit, an analog signal indicative of a voltage state produced by an analog to digital converter (ADC) component, wherein the DAC is characterized as a return to open DAC;
- in the data phase, providing through a resistive circuit, the analog signal produced by the DAC to a first input of a combiner, wherein the resistive circuit provides a resistance to the analog signal produced by the DAC;
- in the data phase, providing an analog input signal to a second input of the combiner and providing an output of the combiner to an input of the ADC component;
- in a reset phase, enabling a reset bypass path from the output of the DAC to the first input of the combiner to electrically short the output of the DAC to the first input of the combiner, wherein the output of the DAC is at a high impedance state during the reset phase.
A feedback circuit for an analog to digital converter (ADC), the feedback circuit comprising:
- a digital to analog converter (DAC) including an output for providing an analog signal representative of digital signal received at an input of the DAC during a data phase, wherein the DAC is characterized as a return to open DAC wherein the output of the DAC is at a high impedance state during a reset phase;
- a resistive circuit including a first terminal coupled to the output of the DAC and a second terminal coupled to a combiner node of an ADC to provide a resistance between the output of the DAC and the combiner node during a data phase;
- a reset bypass circuit that when enabled during the reset phase, provides a bypass path between the output of the DAC and the combiner node to electrically short the output of the DAC to the combiner node.
Dependencies are inferred from the claim text.