Switched-Capacitor Time-to-Voltage Conversion Beyond Supply Rails
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional time-to-voltage converters face challenges with reduced available voltage due to decreasing power supply levels, leading to increased thermal noise, decreased output impedance, and nonlinearity, which affects jitter performance and requires additional voltage margins to maintain linear operation.
Innovation Solution
A level-shifting time-to-voltage converter using a switched-capacitor circuit that shifts the output voltage beyond the power supply voltage range by employing a capacitive level-shift, increasing the available voltage and improving linearity and noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power supply voltage levels are decreased, then energy consumption is reduced, but thermal noise increases and output impedance decreases
Solution Approach 1:
The patent extends the output voltage range beyond the power supply voltage rails by using a level-shifting circuit. The switched-capacitor circuit generates output voltages that can exceed VDD and go below VSS, effectively adding a dimensional extension to the voltage range. This allows the time-to-voltage converter to maintain high output impedance and low thermal noise even when operating from low-voltage power supplies.
2Use of energy by moving object
If power supply voltage levels are decreased, then energy consumption is reduced, but linearity deteriorates
Solution Approach 1:
By extending the output voltage range beyond the power supply rails through level-shifting, the patent creates additional voltage headroom that improves the linearity of the current source. The extended range allows for better voltage allocation to the current source transistor, ensuring it operates in a more linear region even at low supply voltages.
Solution Approach 2:
The patent changes the voltage parameters by generating output voltages that exceed the power supply voltage levels. The level-shifting circuit modifies the voltage parameters available to the time-to-voltage converter, allowing the current source to operate with improved linearity by providing greater voltage swing capability.
3Adaptability or versatility
If voltage range is extended beyond power supply levels, then available voltage increases and linearity improves, but device complexity increases
Solution Approach 1:
The patent segments the voltage generation function into two parts: the core time-to-voltage conversion circuit that operates within the power supply rails, and a separate level-shifting circuit that extends the output range. This segmentation allows each part to be optimized independently, managing complexity by dividing the overall function.
Solution Approach 2:
The switched-capacitor level-shifting circuit acts as an intermediary between the core converter and the external circuitry. It mediates the voltage level transformation, allowing the core circuit to operate simply within supply rails while the intermediary handles the complexity of extending the voltage range beyond those rails.
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 enhances the output voltage range, reducing jitter and improving linearity by increasing the slew rate and voltage allocated to the current source, thereby enhancing the performance of time-to-digital and digital-to-time converters.
Implementation Method 1
a switched-capacitor circuit configured to charge an output node to a reset voltage level
Implementation Method 2
configured to shift a voltage on the output node from the reset voltage level to a shifted reset voltage level... employing a capacitive level-shift
Data Source
AI summary
A time-to-voltage converter includes a switched-capacitor circuit configured to charge an output node to a reset voltage level in a first interval of a conversion period and configured to shift a voltage on the output node from the reset voltage level to a shifted reset voltage level in a second interval of the conversion period. The time-to-voltage converter includes a current source selectively coupled to the output node. The current source is configured to provide a constant current to the output node in a third interval of the conversion period. The shifted reset voltage level is outside a voltage range defined by a first power supply voltage level on a first voltage reference node and a second power supply voltage level on a second voltage reference node.