AC coupling circuit integrated with receiver with hybrid stable common-mode voltage generation and baseline wander compensation
First Claim
1. In association with a receiver configured to receive a first input signal, an input signal compensation circuit comprising:
- a first feedback loop adapted to receive a feedback signal, corresponding to data detected from said first input signal, and further adapted to generate a baseline wander correction component in response to said feedback signal;
a second feedback loop configured to generate a common-mode voltage related to a selected reference voltage associated with said first input signal;
a combining mechanism for combining said baseline wander correction component with said common-mode voltage, for use in providing a reconstructed correction component for said first input signal;
wherein said feedback signal is a digital feedback signal;
wherein said first feedback loop further comprises one or more switches, wherein each of said switches is operated by said digital feedback signal to generate a pulsed current that represents said feedback signal, and further represents a selected gain adjustment to compensate for baseline wander in said first input signal;
wherein said combining mechanism includes a summer for combining said pulsed current with a current supplied by said second feedback loop that represents said common-mode voltage; and
wherein said second feedback loop comprises a comparator and a dynamic common-mode current injection device connected to receive an output of the comparator, and to supply current that represents said common-mode voltage in response to said output of the comparator.
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Accused Products
Abstract
In a receiver, an AC-coupling solution uses a fully integrated circuit for simultaneously providing both baseline wander compensation and common-mode voltage generation. Usefully, an integrated capacitor is placed between the receiver input pin and the input buffer, and a high resistive impedance element is connected to the internal high-speed data node after the capacitor. An on-chip voltage generation and correction circuit is connected to the other side of the impedance element to generate a common-mode voltage, and to provide dynamic, fine adjustment for the received data voltage level. The voltage correction circuit is controlled by the feedback of data detected by the clock and data recovery unit (CDRU) of the receiver. The feedback data passes through a weighting element, wherein the amount of feedback gain is adjustable to provide a summing weight and thereby achieve a desired BLW compensation. Register bits are used to control an on-chip reference voltage generator that consists of a resistor ladder to generate the reference voltage.
112 Citations
19 Claims
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1. In association with a receiver configured to receive a first input signal, an input signal compensation circuit comprising:
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a first feedback loop adapted to receive a feedback signal, corresponding to data detected from said first input signal, and further adapted to generate a baseline wander correction component in response to said feedback signal; a second feedback loop configured to generate a common-mode voltage related to a selected reference voltage associated with said first input signal; a combining mechanism for combining said baseline wander correction component with said common-mode voltage, for use in providing a reconstructed correction component for said first input signal; wherein said feedback signal is a digital feedback signal; wherein said first feedback loop further comprises one or more switches, wherein each of said switches is operated by said digital feedback signal to generate a pulsed current that represents said feedback signal, and further represents a selected gain adjustment to compensate for baseline wander in said first input signal; wherein said combining mechanism includes a summer for combining said pulsed current with a current supplied by said second feedback loop that represents said common-mode voltage; and wherein said second feedback loop comprises a comparator and a dynamic common-mode current injection device connected to receive an output of the comparator, and to supply current that represents said common-mode voltage in response to said output of the comparator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. For use in a receiver configured to receive a transmitted input signal affected by baseline wander (BLW) during transmission, a circuit apparatus comprising:
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a first circuit component configured to generate a feedback signal representing data contained in said transmitted input signal; a first set of circuit elements operable by said feedback signal to produce a first signal provided with a BLW compensation value; a second set of circuit elements for generating a second signal representing a common-mode voltage adaptable to said receiver; a second circuit component for producing a reconstructed correction component from said first and second signals, and for combining said reconstructed correction component with said transmitted input signal to compensate said transmitted input signal for BLW effects; and said second set of circuit elements comprises a reference voltage generator, a comparator, and a dynamic common-mode current injection device connected to receive an output of the comparator, and to supply current that represents said common-mode voltage in response to said output of the comparator. - View Dependent Claims (10, 11)
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12. In association with a receiver configured to receive a first input signal, a method comprising the steps of:
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receiving a feedback signal by a first feedback loop, wherein the feedback signal corresponds to data detected from said first input signal; generating a baseline wander correction component in response to said feedback signal; generating a common-mode voltage related to a selected reference voltage associated with said first input signal using a second feedback loop; combining, using a combining mechanism, said baseline wander correction component with said common-mode voltage for use in providing a reconstructed correction component for said first input signal; wherein said feedback signal is a digital feedback signal; wherein said first feedback loop further comprises one or more switches, wherein each of said switches is operated by said digital feedback signal to generate a pulsed current that represents said feedback signal, and further represents a selected gain adjustment to compensate for baseline wander in said first input signal; wherein said combining mechanism includes a summer for combining said pulsed current with a current supplied by said second feedback loop that represents said common-mode voltage; and wherein said second feedback loop comprises a comparator and a dynamic common-mode current injection device connected to receive an output of the comparator, and to supply current that represents said common-mode voltage in response to said output of the comparator. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification