Differential Transimpedance Amplifier With Shared Current Source
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Solution Overview
Problem
Known transimpedance amplifiers face issues with high power consumption and noise, as well as bandwidth limitations, which affect their performance in applications such as optical communication.
Innovation Solution
The proposed solution involves sharing a current source between two transimpedance amplifiers, each with a MOS transistor amplification stage, allowing for reduced power consumption and improved signal-to-noise ratio through differential operation and optimized photodiode configuration, which also enhances spatial sensitivity and radiation diagram aperture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a single current source is used to bias one amplification stage, then the device complexity is low, but the power consumption is high and the signal-to-noise ratio is poor
Solution Approach 1:
The patent merges two transimpedance amplifier channels into a single integrated device, allowing them to share common components including the current source, thereby reducing overall power consumption while maintaining differential operation for improved signal-to-noise ratio
Solution Approach 2:
The shared current source serves multiple functions by providing bias current to both amplification stages simultaneously, making it a universal component that reduces total power consumption while supporting differential amplification operation
2Use of energy by moving object
If a single current source is shared between two amplification stages, then the power consumption is reduced, but the noise performance may deteriorate
Solution Approach 1:
The patent converts the potential harmful effect of shared current noise into a benefit by using differential operation, where the noise appears as a common-mode signal that is rejected at the differential output, thereby improving the signal-to-noise ratio
Solution Approach 2:
The differential configuration provides implicit feedback rejection of common-mode noise signals from the shared current source, as the differential output subtracts the common noise component, effectively filtering out the harmful noise
3Adaptability or versatility
If traditional single-channel transimpedance amplifiers are used, then the device structure is simple, but the spatial sensitivity and radiation diagram aperture are limited
Solution Approach 1:
The patent combines two transimpedance amplifier channels into a single device with shared components, enabling differential operation that improves spatial sensitivity and radiation diagram aperture while maintaining a compact integrated structure
Solution Approach 2:
The patent transitions from single-ended to differential operation, adding a dimensional aspect to the signal processing that enhances spatial sensitivity and allows for improved radiation pattern characteristics
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 reduces power consumption and enhances the signal-to-noise ratio by 3 dB compared to traditional designs, while improving spatial sensitivity and communication capabilities through differential operation and shared current source utilization.
Implementation Method 1
a current delivered by one photodiode is read by a corresponding transimpedance amplifier
Data Source
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AI summary
The present disclosure relates to a device (1) comprising a first transimpedance amplifier (TIA1) comprising a first amplification stage (S1) with a first MOS transistor (T1), a second transimpedance amplifier (TIA2) comprising a second amplification stage (S2) with a second MOS transistor (T2), and a current source (100) series-connected with the first and second amplification stages (S1, S2), the current source (100) having a first terminal coupled to the drain of the first MOS transistor (T1) and a second terminal coupled to the drain of the second MOS transistor (T2).