Current Detection Device with Reconfigurable Capacitor Network
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Solution Overview
Problem
Current spectrometer detection circuits face challenges in accurately and efficiently detecting currents over a large dynamic range, particularly in miniaturized and portable devices, due to high noise levels and slow detection speeds, which limits their ability to detect ion currents as low as 10 femto-ampere.
Innovation Solution
A high-speed and low-noise current detection device comprising an integrating circuit with a network of capacitors for gain setting, an analog-to-digital converter, and a processor that converts current to a voltage ramp, digitizes it, and reconfigures the capacitors to adjust gain settings and integration time, enabling precise detection of currents across a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a detection circuit using an op-amp with very high open-loop gain is used, then the current detection sensitivity is improved, but the noise level increases and recovery time from saturation lengthens
Solution Approach 1:
The patent applies dynamics by making the gain setting adjustable and reconfigurable rather than fixed. The detection circuit can dynamically change its gain setting to match the expected signal level, allowing high gain to be used only when necessary for small signals, while using lower gain for larger signals to avoid saturation and reduce noise impact.
Solution Approach 2:
The patent changes the gain parameter of the detection circuit by providing multiple selectable gain settings. This allows the system to adapt the amplification level according to the signal magnitude, improving detection sensitivity for small currents while preventing saturation and excessive noise amplification for larger currents.
2Measurement precision
If the gain setting is increased to detect smaller currents, then the detection sensitivity is improved, but the detection range and speed are reduced
Solution Approach 1:
The patent makes the gain setting dynamic and adjustable, allowing the system to switch between different gain levels based on the expected signal magnitude. This enables fast detection for large signals using low gain while maintaining high sensitivity for small signals using high gain, resolving the trade-off between sensitivity and speed.
Solution Approach 2:
The patent applies preliminary action by predicting or estimating the expected signal level before detection and pre-configuring the appropriate gain setting. This allows the system to be ready with the optimal gain level already set, avoiding the need to wait for signal arrival before adjusting gain, thus maintaining both speed and sensitivity.
3Device complexity
If a fixed gain setting is used, then the device complexity is reduced, but the adaptability to different current magnitudes is limited
Solution Approach 1:
The patent introduces dynamic reconfigurability to the gain setting through switches and control logic, allowing the circuit to adapt to different current magnitudes. While this increases complexity compared to a fixed gain circuit, the added complexity is minimal and enables the system to handle a wide dynamic range from 100 nA to 10 fA effectively.
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 significantly improves detection speed and accuracy, allowing for the detection of ion currents as low as 10 pico-ampere and reduces noise interference, enhancing the performance of spectrometers by trading measurement speed for sensitivity and immunity to offset errors.
Implementation Method 1
an integrating circuit including a network of capacitors for providing a gain setting and configured to convert the current to a voltage ramp over a length of integration time
Implementation Method 2
a reset switch configured to connect an input and an output of the network of capacitors when the reset switch is turned on
Implementation Method 3
an analog-to-digital converter (ADC) configured to digitize the voltage ramp into a plurality of voltage samples
Data Source
AI summary
A device of detecting a current from a sensor is disclosed. The device includes an integrating circuit including a network of capacitors for providing a gain setting and configured to convert the current to a voltage ramp over a length of integration time, the integrating circuit further including a reset switch configured to connect an input and an output of the network of capacitors; an ADC configured to digitize the voltage ramp into a plurality of voltage samples; and a set of modules including an analyzing module configured to analyze the plurality of voltage samples to determine a slope of the voltage ramp; an outputting module configured to determine a magnitude of the current based on the slope of the voltage ramp and the gain setting; and a reconfiguring module that is configured to reconfigure the network of capacitors and reset the voltage ramp via the reset switch.