Open-Loop ADC Amplifier Gain Compensation for Parasitic Coupling
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Solution Overview
Problem
Existing amplifiers in pipelined analog-to-digital converters face challenges in maintaining gain due to the coupling effect of parasitic capacitors, which requires high open-loop gain and bandwidth, leading to high power consumption and unsuitability for advanced semiconductor manufacturing processes.
Innovation Solution
The proposed amplifier includes a differential input pair, a reset circuit, and compensation circuits that provide compensation voltages to offset the negative feedback from parasitic capacitors, ensuring the gain is not reduced and reducing power consumption by alleviating bandwidth and gain requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback paths are used to form closed loops with high open-loop gain and bandwidth, then gain accuracy is improved, but power consumption increases and it becomes unsuitable for advanced semiconductor manufacturing processes
Solution Approach 1:
The patent extracts and eliminates the feedback paths that form closed loops, transitioning from a closed-loop amplifier architecture to an open-loop amplifier architecture. This removal of the feedback mechanism eliminates the need for high open-loop gain and bandwidth, thereby reducing power consumption while maintaining acceptable gain accuracy through alternative means.
Solution Approach 2:
The patent changes the operating parameters of the amplifier by transitioning from closed-loop operation requiring high gain and bandwidth to open-loop operation with lower gain and bandwidth requirements. This parameter change allows the amplifier to function effectively in advanced semiconductor processes with reduced power consumption.
2Use of energy by moving object
If open-loop amplifier is used to save power consumption, then power consumption is reduced, but gain is reduced due to coupling effect of parasitic capacitors
Solution Approach 1:
The patent converts the harmful coupling effect of parasitic capacitors into a beneficial compensation mechanism. By intentionally introducing compensation capacitors that mimic the parasitic effects, the circuit generates compensation voltages that counteract the gain reduction caused by parasitic capacitance, thereby maintaining accurate gain measurement while operating in low-power open-loop mode.
Solution Approach 2:
The patent introduces compensation capacitors and compensation voltage sources as intermediary elements between the input and output of the open-loop amplifier. These intermediaries generate compensation voltages that offset the negative effects of parasitic capacitors, allowing the amplifier to maintain accurate gain without requiring high open-loop gain or feedback mechanisms.
3Measurement precision
If high open-loop gain and bandwidth are designed, then gain accuracy is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent removes the complex feedback network and high-gain amplifier stages from the design, simplifying the overall amplifier architecture. By eliminating the closed-loop feedback mechanism, the design becomes less complex and more suitable for advanced semiconductor manufacturing processes while maintaining gain accuracy through the open-loop configuration with compensation.
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
The solution effectively compensates for the gain reduction caused by parasitic capacitors, maintaining amplifier performance while reducing power consumption, making it suitable for advanced semiconductor processes.
Implementation Method 1
a portion of the non-inverting output wire is disposed adjacent to the first non-inverting input wire to form a first compensation capacitor with the first non-inverting input wire
Implementation Method 2
a gain of an open-loop amplifier may be reduced due to a coupling effect of parasitic capacitors
Implementation Method 3
a portion of the inverting output wire is disposed adjacent to the first inverting input wire to form a second compensation capacitor with the first inverting input wire
Implementation Method 4
a gain of an open-loop amplifier may be reduced due to a coupling effect of parasitic capacitors
Data Source
AI summary
An amplifier includes a first differential input pair, a reset circuit, a first compensation circuit and a second compensation circuit. First differential input pair includes a first non-inverting input terminal and a first inverting input terminal, and is configured to amplify a voltage difference between first non-inverting input terminal and first inverting input terminal to generate a non-inverting output voltage and an inverting output voltage of amplifier. Reset circuit is coupled with first differential input pair, and is configured to reset non-inverting output voltage and inverting output voltage of amplifier according to a reference voltage. First compensation circuit is configured to provide a first compensation voltage to first non-inverting input terminal, and first compensation voltage is positively correlated with non-inverting output voltage. Second compensation circuit is configured to provide a second compensation voltage to first inverting input terminal, and second compensation voltage is positively correlated with inverting output voltage.