Op-Amp Output Isolation by Switching Off Miller Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Operational amplifiers experience performance degradation due to load signal coupling via the Miller compensation module, leading to undesired spikes and notches in computation results, which delays the charging procedure of the load signal.
Innovation Solution
A coupling isolation method that involves switching off the Miller compensation signal path at a first time point and electrically connecting the output end of the operational amplifier to the load at a second time point, using a delay unit to generate interruption and output indication signals, thereby preventing the load signal from coupling into the operational amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the output switch is closed to output the computation result, then the computation result can be accessed by external circuits, but load signal couples into the operational amplifier through the Miller compensation module causing performance degradation
Solution Approach 1:
The Miller compensation signal path is switched off before the output switch is closed. The delay unit generates a switching control signal that activates the switching off action in advance, preventing the load signal from coupling into the operational amplifier through the Miller compensation module when the output is accessed.
Solution Approach 2:
The signal path is segmented into the Miller compensation signal path and the output signal path. By independently controlling the Miller compensation signal path through a separate switching mechanism, the patent prevents interference between the compensation function and the output function, eliminating the coupling problem.
2Stability of the object's composition
If the Miller compensation signal path is kept on to maintain frequency response compensation, then frequency response is compensated correctly, but load signal couples into the operational amplifier causing spikes and notches in computation result
Solution Approach 1:
The Miller compensation signal path is switched off in advance before the output switch closes. The delay unit ensures that the switching off action occurs before the potential harmful coupling can occur, preventing spikes and notches in the computation result while maintaining frequency response compensation during normal operation.
3Ease of operation
If charges stored in output switch are redistributed when output switch is closed, then output can be accessed, but singularities are induced in computation result and voltages of nodes N1 and N2
Solution Approach 1:
The Miller compensation signal path is switched off before the output switch is closed to prevent charge redistribution from inducing singularities. By performing this switching action in advance, the patent eliminates the harmful effects of charge redistribution on computation result accuracy while preserving output accessibility.
4Speed
If restoration of computation result accelerates recovery of voltages VN1 and VN2, then computation result restores quickly, but leakage current is generated delaying charging procedure of load signal
Solution Approach 1:
The harmful second coupling effect is extracted and eliminated by switching off the Miller compensation signal path. This prevents the acceleration of voltage recovery that would otherwise generate leakage current and delay load signal charging, while allowing the computation result to be output correctly.
Data Source
AI summary
A coupling isolation method for preventing a load signal from coupling into an operational amplifier is disclosed. The coupling isolation method includes generating a system signal before the operational amplifier outputs a computation result, switching off a Miller compensation signal path of the operational amplifier at a first time point according to the system signal, and electrically connecting an output end of the operational amplifier and a load at a second time point according to the system signal to output the computation result.