Invention Grant
- Patent Title: Offset cancellation in a transimpedance amplifier (TIA) circuit
- Patent Title (中): 跨阻放大器(TIA)电路中的偏移消除
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Application No.: US14282011Application Date: 2014-05-20
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Publication No.: US09148094B1Publication Date: 2015-09-29
- Inventor: Robert Swoboda
- Applicant: Avago Technologies General IP (Singapore) Pte. Ltd.
- Applicant Address: SG Singapore
- Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
- Current Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
- Current Assignee Address: SG Singapore
- Main IPC: H03F3/08
- IPC: H03F3/08 ; H03F1/02

Abstract:
Offset measurement and cancellation circuitry is employed in a transimpedance amplifier (TIA) circuit for directly measuring the offset in the TIA input voltage and for canceling the offset from the TIA output voltage. Employing the offset measurement and cancellation circuitry eliminates the need to use large transistors in the input stage of the TIA in order to reduce or eliminate the offset, which can increase noise and reduce Rx sensitivity. The offset measurement and cancellation circuitry of the invention obviate the need of making a tradeoff between the amount of noise and the magnitude of the offset that will be tolerated. The offset measurement and cancellation circuitry also eliminate the need for additional overhead in the decision threshold in order to avoid false triggering of the decision circuitry of the optical receiver due to noise.
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