Amplifier Offset Correction Using Dual Bias Voltage Sources
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Solution Overview
Problem
Existing methods for correcting offset voltage in amplifier circuits require high-precision, expensive variable voltage sources to achieve precise correction, which is not economically feasible with existing techniques.
Innovation Solution
A semiconductor device utilizing two variable voltage sources to set an ideal operating point and correct offset voltage, where one source adjusts the operating point and the other corrects the shift amount, allowing for high-precision correction using low-precision, cost-effective voltage sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single variable voltage source is used to correct offset voltage, then the correction can be achieved, but high-precision voltage sources are required which increases cost
Solution Approach 1:
The patent divides the offset voltage correction into two independent stages: coarse correction and fine correction. Each stage uses a separate variable voltage source with different precision requirements. The coarse correction voltage source handles large offset adjustments, while the fine correction voltage source handles small residual offsets. This segmentation allows each voltage source to be optimized for its specific function, reducing overall system cost while maintaining high correction precision.
2Measurement precision
If bias voltage is adjusted to correct offset voltage, then offset correction is achieved, but the correction component is amplified and output requiring high-precision correction
Solution Approach 1:
The correction system is segmented into two independent correction paths: a coarse correction path that handles large bias adjustments and a fine correction path that handles small residual adjustments. This segmentation reduces the precision requirement for each individual correction component, as the fine correction only needs to handle the remaining small offset after coarse correction, simplifying the overall correction system design.
Solution Approach 2:
The patent introduces an intermediary fine correction voltage source that acts as a mediator between the coarse correction stage and the final output. This fine correction voltage source compensates for any remaining offset errors after coarse correction, ensuring high overall precision without requiring the coarse correction source to be extremely precise, thus reducing system complexity.
Data Source
AI summary
A semiconductor device includes: an amplifier circuit that has an inverting input terminal, a non-inverting input terminal, and an output terminal; a first variable voltage source that generates a first bias voltage having a voltage value corresponding to a first set value; a second variable voltage source that generates a second bias voltage having a voltage value corresponding to a second set value; a first resistor whose one end is connected to the inverting input terminal; a second resistor that is connected between the output terminal and the inverting input terminal; a third resistor whose one end is connected to the non-inverting input terminal; and a fourth resistor that is connected between the second variable voltage source and the non-inverting input terminal. The first bias voltage is provided to the other end of the first resistor. An input signal is provided to the other end of the third resistor.