Gain compensation for an open loop programmable amplifier for high speed applications
First Claim
1. A circuit for maintaining constant gain in an open loop gain stage amplifier, the circuit comprising:
- a reference signal generator configured to generate a plurality of reference voltages;
a gain compensation circuit, including;
a reference selector configured to select one of the plurality of reference voltages for each of a plurality of gain stages;
an error amplifier configured to output a control voltage signal to a selector, where the control voltage signal keeps gain constant over process/voltage/temperature (PVT) and adjusts a bias current of a differential pair of transistors;
a selector configured to select which of a plurality of degeneration resistors in the open loop gain stage amplifier to apply the control voltage signal, wherein the control voltage signal is applied to a gate of at least one of the plurality of degeneration resistors in the open loop gain stage amplifier.
1 Assignment
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Accused Products
Abstract
Various embodiments relate to a method and apparatus for maintaining constant gain in an open loop gain stage amplifier, the circuit including a reference signal generator configured to generate a plurality of reference voltages, a gain compensation circuit, including a reference selector configured to select one of the plurality of reference voltages for each of a plurality of gain stages, an error amplifier configured to output a control voltage signal to a selector, a selector configured to select which of a plurality of degeneration resistors in the open loop gain stage amplifier to apply the control voltage signal wherein the voltage signal is applied to the gate of at least one of the plurality of degeneration resistors in the open loop gain stage amplifier.
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Citations
12 Claims
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1. A circuit for maintaining constant gain in an open loop gain stage amplifier, the circuit comprising:
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a reference signal generator configured to generate a plurality of reference voltages; a gain compensation circuit, including; a reference selector configured to select one of the plurality of reference voltages for each of a plurality of gain stages; an error amplifier configured to output a control voltage signal to a selector, where the control voltage signal keeps gain constant over process/voltage/temperature (PVT) and adjusts a bias current of a differential pair of transistors; a selector configured to select which of a plurality of degeneration resistors in the open loop gain stage amplifier to apply the control voltage signal, wherein the control voltage signal is applied to a gate of at least one of the plurality of degeneration resistors in the open loop gain stage amplifier. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for maintaining constant gain in an open loop gain stage amplifier, the method comprising the steps of:
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generating, by a reference signal generator, a plurality of reference voltages; selecting, by a reference selector in a gain compensation circuit, one of the plurality of reference voltages for each of a plurality of gain stages; outputting, by an error amplifier, a control voltage signal to a selector, where the control voltage signal keeps gain constant over process/voltage/temperature (PVT) and adjusts a bias current of a differential pair of transistors; selecting, by a selector, which of a plurality of degeneration resistors in the open loop gain stage amplifier to apply the control voltage signal, wherein the control voltage signal is applied to a gate of at least one of the plurality of degeneration resistors in the open loop gain stage amplifier. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification