Charge transfer circuit for compact modulators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Delta-Sigma modulation circuits face challenges in achieving high-speed charge transfer and maintaining signal integrity, particularly in large arrays of modulators, where supply spikes and clock jitter lead to noise and reduced signal-to-noise ratios, especially when dealing with low-impedance detectors and high signal currents.
Innovation Solution
A charge transfer circuit using a current generation element with NMOS and PMOS FET transistors in a push-pull configuration, allowing for bi-directional charge transfer and rejecting supply-induced errors, which sets the charge packet magnitude independently of supply voltage and reduces noise by controlling current flow through gate biases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional charge transfer circuits are used in large arrays of modulators, then charge transfer speed can be increased, but supply spikes and clock jitter lead to increased noise and reduced signal-to-noise ratios
Solution Approach 1:
The patent introduces a current generation element as an intermediary between the charge transfer circuit and the supply voltage. This current source generates charge packets with magnitudes independent of supply voltage variations, thereby mediating the harmful effects of supply spikes and clock jitter while maintaining fast charge transfer capability
Solution Approach 2:
The patent changes the parameter of charge packet magnitude generation from being supply-voltage-dependent to being current-source-dependent. By using a current generation element, the charge packet magnitude is determined by current integration over time rather than direct voltage sampling, which fundamentally changes how supply variations affect the system
2Productivity
If high signal currents are used to achieve faster integration, then integration speed is improved, but supply-induced errors and noise increase
Solution Approach 1:
The current generation element acts as an intermediary that decouples the relationship between signal current magnitude and supply voltage. High signal currents can be used for fast integration without directly coupling to supply voltage variations, as the current source provides a stable reference that is independent of supply spikes
Solution Approach 2:
The patent segments the charge transfer function into discrete charge packets generated by the current source. Each charge packet is independently generated with a magnitude determined by current integration, allowing high-speed operation while maintaining precision through the segmented, controlled delivery of charge
3Area of moving object
If smaller pixel sizes are used to increase array density, then area is reduced, but maintaining signal integrity and rejecting noise becomes more difficult
Solution Approach 1:
The patent changes the fundamental parameter of charge packet generation from voltage-based to current-based. This allows smaller pixels to maintain signal integrity because the current generation mechanism is inherently more resistant to area-related parasitic effects and supply variations, which become more significant as pixel size decreases
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 enhances signal-to-noise ratios and allows for faster integration with reduced noise, enabling higher resolution and smaller pixel sizes while minimizing supply-induced errors and clock jitter effects.
Implementation Method 1
A charge transfer circuit using a current generation element with NMOS and PMOS FET transistors in a push-pull configuration, allowing for bi-directional charge transfer and rejecting supply-induced errors, which sets the charge packet magnitude independently of supply voltage and reduces noise by controlling current flow through gate biases
Data Source
AI summary
The present disclosure provides a current generation circuit. In one aspect, the circuit includes a current source transistor and a current sink transistor connected to the current source transistor in series, with respective sources of the current source and sink transistors being connected with each other at a common node. A voltage difference between respective gates of the current source and sink transistors defines a current value flowing through the series, the voltage difference being variable such that the current value is either time-dependent or time-independent. Respective drains of the current source and sink transistors provide a high resistance output necessary to provide a current source or sink function thereby rejecting influence of drain variation or error on the current value.