Difference Amplifier Reset Circuit for Offset and Noise Suppression
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Solution Overview
Problem
Existing circuit designs for difference amplifiers in event-based vision sensors suffer from offset errors and device noise, leading to increased power consumption and reduced signal processing efficiency, as they attempt to cancel offsets and reduce noise, resulting in larger circuit sizes and higher power consumption.
Innovation Solution
A circuit configuration that includes an amplifier with an input stage and an output stage connected via a switch, utilizing a transistor to reset the amplifier and a diode to form a current path, which reduces leakage currents and effectively cancels DC offsets and device noise, thereby improving signal amplification and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing circuit design schemes are used to cancel offset and reduce device noise, then offset cancellation and noise reduction are achieved, but circuit size increases and power consumption increases due to added circuits
Solution Approach 1:
The patent merges the offset cancellation function into the amplifier's reset mechanism by connecting the reset switch between the output terminal and the body terminal of the transistor. This integration eliminates the need for separate offset cancellation circuits, thereby reducing circuit size while maintaining signal accuracy.
Solution Approach 2:
The reset switch serves multiple functions: it resets the amplifier output to a reference voltage, cancels DC offsets, and reduces device noise. By making the reset mechanism multi-functional, the patent avoids adding separate circuits for each function, thus reducing overall circuit complexity.
2Measurement precision
If existing circuit design schemes are used to cancel offset and reduce device noise, then offset cancellation and noise reduction are achieved, but power consumption increases in each pixel
Solution Approach 1:
The patent combines offset cancellation and noise reduction functions into the existing amplifier reset mechanism, eliminating the need for additional active circuits that would consume power. This integration reduces power consumption while maintaining signal accuracy.
Solution Approach 2:
The amplifier uses its own reset mechanism to perform offset cancellation and noise reduction, rather than relying on external dedicated circuits. This self-service approach reduces the overall power consumption of the pixel circuit.
3Ease of operation
If reset switch is connected between output terminal and ground, then amplifier is reset to ground voltage, but DC offset cannot be effectively cancelled and leakage current increases
Solution Approach 1:
Instead of connecting the reset switch to ground voltage, the patent connects it to the body terminal of the transistor, which is at a different potential. This inverted connection approach enables effective DC offset cancellation by referencing the reset voltage to the transistor's body potential rather than ground.
Solution Approach 2:
The body terminal of the transistor serves as an intermediary reference point for the reset switch connection. This intermediary connection allows the reset mechanism to effectively cancel DC offsets by using the body terminal's potential as a reference, rather than directly grounding the output.
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 proposed solution effectively removes systematic false events and inhibits random false events, reducing power consumption and enhancing processing efficiency in event-based vision sensors by suppressing noise and maintaining signal integrity.
Implementation Method 1
the transistor is configured to form a current path between the body node of the transistor and the input stage of the amplifier
Implementation Method 2
a first diode configured to form a current path between the input stage and the output stage of the amplifier so that a leakage current generated by the amplifier flows through the current path
Data Source
AI summary
A circuit configured to amplify a signal from which an offset is cancelled includes an amplifier including an input stage configured to receive an input signal, the amplifier configured to amplify the input signal and output the amplified signal, and a switch including a transistor configured to reset the amplifier in response to a reset signal, the transistor including a body node connecting the transistor to the circuit, the transistor being configured to form a current path between the body node of the transistor and the input stage of the amplifier.