Adaptive Photodiode Circuit for Wide Dynamic Range
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Solution Overview
Problem
Conventional photodetector circuits face challenges in achieving linear operation over a large dynamic range of input currents, leading to high power consumption, especially in battery-powered applications, due to the need for amplifiers to handle a wide range of input swing.
Innovation Solution
The proposed photodiode circuit includes a transimpedance amplifier with a receive signal strength indicator that adaptively adjusts the current through an amplifier stage based on the DC component of the input current, and uses a shielded resistor and switchable parallel current sinks to reduce power consumption and noise levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the linear input range of the amplifier is adjusted to a high value to handle high input amplitude, then the amplifier can operate linearly over a wide dynamic range, but the power consumption increases significantly
Solution Approach 1:
The patent implements adaptive linearization that dynamically adjusts the linear input range of the amplifier based on the detected signal level. When the input signal amplitude is high, the system expands the linear range to maintain linearity; when the input signal is low, the system reduces the linear range to minimize power consumption. This dynamic adaptation allows the amplifier to operate efficiently across varying signal conditions without continuously consuming high power.
Solution Approach 2:
The system changes the operational parameters of the amplifier based on the input signal characteristics. By detecting the signal level and adjusting the linear input range parameter accordingly, the system optimizes the trade-off between linearity performance and power consumption. This parameter adaptation enables the amplifier to switch between different operating modes to match the actual signal conditions.
2Reliability
If post amplifiers are designed to be linear for a wide range of input swing, then they can handle large dynamic range signals, but power consumption increases
Solution Approach 1:
The patent employs dynamic linearization techniques that adjust the linearity characteristics of post amplifiers based on the actual input signal swing. Instead of maintaining fixed wide-range linearity, the system adaptively modifies the amplifier's linear operating range to match the current signal conditions, thereby reducing power consumption while maintaining adequate linearity when needed.
Solution Approach 2:
The system uses feedback mechanisms to monitor the input signal characteristics and adjust the amplifier operation accordingly. By continuously detecting the signal level and feeding this information back to control the amplifier's linearization, the system ensures optimal linearity performance only when required, rather than maintaining it continuously at the cost of high power consumption.
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 solution allows for efficient operation across a wide range of input currents with reduced power usage and improved noise performance, enabling more efficient detection of electromagnetic radiation in battery-powered devices.
Implementation Method 1
Photodetectors have multiple uses. Essentially, any application that benefits from detection of electromagnetic radiation (photons) can use a photodetector to detect that radiation.
Data Source
AI summary
In accordance with aspects of the present invention, embodiments of a photodiode circuit. A photodiode circuit according to some embodiments includes a transimpedance amplifier; a resistor coupled across the transimpedance amplifier; and an amplifier stage coupled to receive an output from the transimpedance amplifier, wherein the photodiode circuit provides dynamic range across a current range of the photodiode circuit. In some embodiments, the transimpedance amplifier includes a receive signal strength indicator that provides a DC current signal to a tail of a first amplifier stage, the tail providing a current that is adaptively related to the DC current. In some embodiments, the resistor is a shielded resistor. In some embodiments, the adaptive current sink includes a plurality of switchable parallel current sinks.