Mixer Offset Calibration Feedback for DC Offset Reduction
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Solution Overview
Problem
Conventional wireless device mixer circuits face issues with DC offsets leading to carrier leakage, which corrupts modulation and increases device size, cost, and power consumption, making it difficult to sense and reduce these offsets effectively.
Innovation Solution
A mixer circuit with a feedback mechanism that measures and generates a calibration signal to reduce DC offsets between differential signals, using a subcircuit and feedback circuit configuration to adjust currents and minimize chip area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If devices in the circuit are made large to improve matching, then DC offset reduction is improved, but die area increases
Solution Approach 1:
The patent implements a feedback circuit that senses the differential output signals from the mixer and generates calibration signals to adjust the input stage, creating a closed-loop system that automatically compensates for DC offsets without requiring oversized devices
Solution Approach 2:
The patent changes the operating parameters by introducing可调 calibration signals that modify the input differential signals to counteract the DC offsets, allowing standard-sized devices to achieve proper matching through parameter adjustment rather than physical size increase
2Manufacturing precision
If devices in the circuit are made large to improve matching, then DC offset reduction is improved, but power consumption increases
Solution Approach 1:
The feedback mechanism continuously monitors output signals and adjusts calibration signals in real-time, enabling standard-sized devices to maintain proper matching without the excessive power consumption that would result from using oversized devices throughout the circuit
3Measurement precision
If DC offset sensing circuitry is added to the output, then offset measurement capability is improved, but circuit loading increases
Solution Approach 1:
The patent introduces an intermediary feedback circuit that couples to the output stage and provides offset sensing capability without directly loading the main signal path, using the feedback topology to isolate the measurement function from the primary signal processing path
Data Source
AI summary
A circuit including a subcircuit having differential signals, and a feedback circuit coupled to the subcircuit. The feedback circuit is configured to measure an offset between the differential signals, to generate a calibration signal in response to the measurement, and to reduce the offset in response to the calibration signal.