Amplifier Load Resistance Correction With Dual Digital-Analog Control
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Solution Overview
Problem
Existing amplifier circuits face challenges in accurately controlling resistance values and maintaining noise immunity due to limitations in variable resistance circuits, which suffer from discrete resistance value adjustments and sensitivity to environmental changes like temperature fluctuations.
Innovation Solution
The amplifier circuit employs a dual-control mechanism, using digital codes to make rough adjustments and analog control voltages for fine tuning of resistance values, incorporating NMOS and PMOS transistors with resistors in series and parallel configurations, along with a correction circuit that adjusts resistance values through digital and analog methods to achieve precise control and reduce noise sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If digital control is used to adjust resistance values, then ease of operation is improved, but manufacturing precision deteriorates due to discrete adjustment steps
Solution Approach 1:
The resistance adjustment is divided into two independent segments: digital control for coarse adjustment and analog control for fine adjustment. The digital control section handles large-step resistance changes through discrete control signals, while the analog control section handles small-step refinements through continuous voltage control, allowing both ease of operation and high precision to be achieved simultaneously
Solution Approach 2:
The patent merges digital control and analog control into a unified resistance adjustment system. The digital control output and analog control output are combined to jointly regulate the resistance value, enabling the system to benefit from both the operational simplicity of digital control and the precision of analog control
2Manufacturing precision
If analog control is used to adjust resistance values, then manufacturing precision is improved, but ease of operation deteriorates due to sensitivity to noise and environmental changes
Solution Approach 1:
The digital control acts as an intermediary that provides stable, noise-resistant baseline control. By handling the coarse adjustment through digital signals that are inherently more resistant to noise and environmental interference, the system reduces the burden on the analog control section, allowing it to focus solely on precise fine-tuning without being overwhelmed by operational complexity
Solution Approach 2:
The control function is segmented such that digital control handles the noisy, environmentally-sensitive aspects of resistance adjustment through robust discrete signaling, while analog control handles only the clean, precision-oriented fine-tuning portion, isolating the precision function from operational complexities
3Reliability
If variable resistance circuit is used to correct resistance variations, then reliability is improved, but device complexity increases due to additional control circuits
Solution Approach 1:
The resistance control system is made dynamic and adaptive through dual control mechanisms. Rather than using a static single-control approach, the system dynamically switches between digital and analog control modes depending on the adjustment requirements, allowing reliable resistance correction while managing complexity through intelligent control strategy rather than hardware redundancy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for accurate resistance value control, improving noise immunity by combining digital and analog control methods, enabling robust resistance value adjustments that are less sensitive to environmental changes, thus maintaining circuit stability and performance.
Implementation Method 1
a PMOS transistor 613 as a variable resistance is connected in parallel to the resistor 611. A gate voltage VG is supplied to a gate of the PMOS transistor 613, and by controlling the voltage VG, the PMOS transistor 613 controls on-resistance corresponding to a gate-source voltage.
Implementation Method 2
an input circuit including NMOS transistors 11A, 11B
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
An amplifier circuit includes: an input circuit (10) configured to receive an input signal; a load circuit (10) that is provided in series with the input circuit and includes a first variable resistance unit and a second variable resistance unit, a resistance value of the first variable resistance unit being controlled by a digital code, a resistance value of the second variable resistance unit being controlled by an analog control voltage; and a correction circuit (30) and including a third variable resistance unit (35) having a circuit configuration corresponding to the first variable resistance unit and a fourth variable resistance unit (36) having a circuit configuration corresponding to the second variable resistance unit, a resistance value of the third variable resistance unit being controlled by the digital code, a resistance value of the fourth variable resistance unit being controlled by the analog control voltage, the correction circuit being configured to correct a resistance value of the load circuit, the amplifier circuit makes it possible to roughly adjust the resistance value by the digital code and finely adjust the resistance value by the analog control voltage.