Band-gap current repeater
AssigneeQUALCOMM Incorporated
InventorsNam Van Dang, Rajeev Jain, Terrence Brian Remple, Jingcheng Zhuang, Mong Chit Wong
Life of this patent
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Abstract
A series of current repeaters with localized feedback is provided. Each current that precedes a subsequent current repeater in the series is configured to receive a feedback current from the subsequent current repeater and generate an error signal accordingly with a differential amplifier so as to reduce current repetition errors that would otherwise result from an offset voltage in the differential amplifier.
Claims20
A current repeater in a series of current repeaters, comprising:
- a plurality of first transistors coupled in parallel to share an internal reference current so as to generate a reference voltage at the gates of the first transistors;
- a plurality of second transistors coupled in parallel to share a feedback reference current from a successive current repeater in the series, wherein the reference voltage is coupled to the gates of the first transistors and to the gates for a majority of the second transistors, and wherein the gates of a remainder of the second transistors are configured to generate a feedback voltage;
- an error amplifier configured to compare the reference voltage to the feedback voltage to generate an error signal;
- and
- a first current source configured to drive a forwarded reference current to the successive current repeater responsive to the error signal.
A method for a current repeater in a series of current repeaters, comprising:
- driving an internal reference current to a plurality of first transistors coupled in parallel so as to drive a portion of the internal reference current through each first transistor;
- driving a feedback reference current from a subsequent current repeater in the series to a plurality of second transistors coupled in parallel so as to drive a portion of the feedback reference current through each second transistor;
- generating an error signal responsive to a difference between a reference voltage developed at the gates of each first transistor and at the gates of a majority of the second transistors and a feedback voltage developed at the gates of a remaining minority of the second transistors;
- generating a forwarded reference current responsive to the error signal;
- and
- driving the forwarded reference current to a subsequent current repeater in the series.
A current repeater in a series of current repeaters, comprising;
- a first current source configured to generate a forwarded reference current for a subsequent current repeater in the series responsive to an error signal;
- a differential amplifier configured to amplify a difference between a reference voltage and a feedback voltage to generate the error signal, the differential amplifier having an offset voltage;
- and
- means for generating the reference voltage and the feedback voltage so as to reduce an effect of the offset voltage on a difference between the forwarded reference current and a received reference current from a previous current repeater in the series.
Dependencies are inferred from the claim text.