Floating Switched-Capacitor Front End for Beyond-Rail Sampling
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Solution Overview
Problem
Traditional approaches face challenges in implementing beyond-the-rails switching in switched capacitor circuits, which limits their ability to sample input signals higher in magnitude than the available supply rails.
Innovation Solution
A switched-capacitor analog front end with a bootstrap generation network that generates a floating supply voltage and bootstrap sampling clock, enabling beyond-the-rails signal sampling with over-voltage protection using bootstrapped switches and a charge-pump-based circuitry for ultra-low-power operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional bootstrapped switching is used in switched capacitor circuits, then the circuit can operate with standard supply rails, but it cannot sample input signals higher in magnitude than the available supply rails
Solution Approach 1:
The patent introduces a floating supply voltage dimension by generating a bootstrap voltage that elevates the entire switched-capacitor circuit's reference level. This allows the circuit to sample signals beyond the original supply rails by adding a voltage offset dimension, enabling beyond-the-rails operation without fundamentally changing the switching mechanism.
Solution Approach 2:
The patent introduces an intermediary bootstrap generation network that creates a floating supply voltage. This intermediary voltage source acts as a mediator between the standard supply rails and the high-magnitude input signals, allowing the switches to operate within their voltage limits while sampling signals that exceed the original supply range.
2Adaptability or versatility
If beyond-the-rails switching is implemented to sample high-magnitude signals, then signal sampling capability is improved, but over-voltage protection becomes necessary to protect downstream circuitry
Solution Approach 1:
The patent implements beforehand cushioning by generating a floating supply voltage that creates a voltage buffer between the high-magnitude input signals and the downstream low-voltage circuitry. This pre-established voltage offset protects downstream components from over-voltage damage while enabling the front-end to sample high-magnitude signals.
Solution Approach 2:
The floating supply voltage acts as an intermediary that isolates downstream circuitry from high-voltage signals. This mediator allows the system to sample high-magnitude signals while preventing voltage damage to sensitive downstream components by maintaining proper voltage level separation.
3Use of energy by moving object
If a floating supply voltage is generated to enable beyond-the-rails operation, then ultra-low-power operation is achieved, but additional circuitry for voltage generation is required
Solution Approach 1:
The patent merges the bootstrap clock generation and floating supply voltage generation into a single integrated bootstrap generation network. This combination achieves ultra-low-power operation by sharing circuit resources and eliminating redundant functionality, while the merged structure manages complexity through functional integration rather than separate independent circuits.
Solution Approach 2:
The bootstrap generation network performs multiple functions simultaneously: generating the bootstrap clock signal and creating the floating supply voltage. This multi-functionality reduces overall power consumption by using a single circuit to accomplish what would otherwise require separate dedicated circuits, achieving energy efficiency without proportionally increasing complexity.
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
Enables ultra-low-power beyond-the-rails switched-capacitor front end for high voltage sensing with input tracking and over-voltage protection, protecting downstream low-voltage circuitry and providing highly linear sampling.
Implementation Method 1
a bootstrap generation network that generates a floating supply voltage and bootstrap sampling clock, enabling beyond-the-rails signal sampling with over-voltage protection using bootstrapped switches and a charge-pump-based circuitry
Data Source
AI summary
A system may include a switched-capacitor analog front end comprising a plurality of switches for sampling an analog physical quantity and a bootstrap generation network electrically coupled to the plurality of switches and configured to generate a bootstrap sampling clock for controlling the plurality of switches and generate a floating supply voltage for the bootstrap sampling clock based on the analog physical quantity.