Amplifier Gain Tracking Circuit for Stable Bandwidth Control
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Solution Overview
Problem
Existing amplifier circuits face challenges in maintaining consistent performance across process, voltage, and temperature variations, particularly in high-bandwidth applications, where controlling forward gain and feedback resistance is difficult, leading to degraded bandwidth and sensitivity.
Innovation Solution
A control circuit using a pair of NMOS transistors, synchronized by PMOS current mirrors, simultaneously controls feedback resistance and forward gain, maintaining a constant ratio and stabilizing the transfer function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional separate control methods are used for forward gain and feedback resistance, then individual parameters can be adjusted, but consistent performance across process, voltage, and temperature variations cannot be maintained
Solution Approach 1:
The patent merges the control of forward gain and feedback resistance into a single synchronized control mechanism. By using a common control signal to adjust both parameters simultaneously, the system maintains their ratio relationship and achieves consistent performance across PVT variations while preserving the ability to adapt to different operating conditions.
Solution Approach 2:
The patent changes the control parameters from independent adjustment of forward gain and feedback resistance to synchronized adjustment based on a common control signal. This parameter change approach allows the system to maintain performance consistency by ensuring that both parameters change in a coordinated manner that preserves their relationship.
2Speed
If high bandwidth operation is implemented, then communication speed is improved, but control of amplifier forward gain and feedback resistance becomes more difficult
Solution Approach 1:
The patent combines the control of forward gain and feedback resistance into a unified control scheme that operates synchronously. This merging of control functions simplifies the operation at high bandwidth by ensuring that both parameters are adjusted together, maintaining stability and performance without requiring complex independent control mechanisms.
3Measurement precision
If photodiode capacitance is present at the input, then optical signal detection is enabled, but bandwidth is significantly degraded
Solution Approach 1:
The patent changes the amplifier parameters (forward gain and feedback resistance) in a synchronized manner to compensate for the effect of photodiode capacitance. By dynamically adjusting these parameters together, the system maintains optimal bandwidth while preserving the ability to detect optical signals accurately.
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 ensures consistent amplifier performance by synchronously adjusting feedback and forward gain, enhancing stability and maintaining bandwidth in high-bandwidth applications.
Implementation Method 1
The pair of NMOS transistors may be controlled by a pair of PMOS current mirrors, which duplicate current flows into the pair of NMOS transistors. The duplicate current flows can help achieve a similar or identical gate-source voltage at both of the NMOS transistors in the pair of NMOS transistors.
Data Source
AI summary
Systems, circuits, and methods for amplifying signals are provided. An illustrative amplifier circuit may include an amplifier that amplifies an input signal received at an input node of the amplifier and provides an amplified version of the input signal as an output signal at an output node of the amplifier, a feedback loop connected between the input node of the amplifier and the output node of the amplifier, and a synchronized gain tracking sub-circuit provided in the feedback loop, where the synchronized gain tracking sub-circuit synchronously controls both a feedback resistance and forward gain of the amplifier circuit.