Ring Oscillator Clock Circuit for PVT-Stable Duty Cycle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dynamic Random-Access Memory (DRAM) oscillators face challenges in generating high-speed clock signals due to frequency and duty cycle deviations caused by process, voltage, and temperature variations (PVT), leading to instability and increased redundancy in design and testing.
Innovation Solution
An oscillation circuit with a power supply generation module producing a positive temperature coefficient voltage, which is used to power an oscillator with multiple ring topological structures, allowing for adjustable transmission speeds and duty cycles to compensate for temperature and voltage changes, reducing PVT deviations and improving frequency stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional oscillator is used to generate clock signals, then the circuit structure is simple, but the frequency and duty cycle deviate under PVT variations leading to instability
Solution Approach 1:
The oscillator is divided into multiple ring topological structures with different transmission speeds. Each ring structure processes the oscillation signal independently, allowing the system to maintain stable frequency and duty cycle under PVT variations while keeping individual ring structures relatively simple
Solution Approach 2:
The circuit uses dynamic element activation based on detected signal characteristics. When frequency or duty cycle deviation is detected, specific ring structures are dynamically activated or deactivated to compensate for PVT variations, maintaining stability without requiring a completely complex fixed structure
2Speed
If the transmission speed of the oscillation signal is increased to meet high-speed requirements, then the clock frequency increases, but the duty cycle deviation increases under PVT variations
Solution Approach 1:
The high-speed transmission path is segmented into multiple ring structures with different speed characteristics. The first ring structure handles high-speed transmission while the second ring structure processes the signal at a lower speed to correct duty cycle deviations, allowing the system to achieve high overall speed while maintaining duty cycle accuracy
Solution Approach 2:
The second ring structure acts as an intermediary that receives the high-speed oscillation signal from the first ring structure, processes it at a lower transmission speed to correct duty cycle deviations, and then outputs the corrected signal, thereby mediating between high-speed requirements and duty cycle accuracy
3Reliability
If redundant test signals and delay units are added to compensate for PVT deviation, then the frequency stability improves, but the device complexity and testing requirements increase
Solution Approach 1:
The multiple ring topological structures serve multiple functions: they generate the oscillation signal, compensate for frequency deviations under PVT variations, correct duty cycle inaccuracies, and provide high-speed transmission. This multi-functionality reduces the need for separate redundant test signals and delay units that would otherwise be required
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 stability of the oscillator frequency by compensating for temperature and voltage changes, reducing the impact of PVT variations and maintaining frequency stability across different conditions, while also enabling the generation of high-speed oscillation signals.
Implementation Method 1
a power supply generation module, configured to generate a positive temperature coefficient voltage based on a positive temperature coefficient current
Data Source
AI summary
An oscillation circuit includes: a power supply generation module and an oscillator. The power supply generation module is configured to generate a positive temperature coefficient voltage based on a positive temperature coefficient current; and the positive temperature coefficient voltage serves as a power supply of the oscillator. The oscillator includes: a first ring topological structure and a second ring topological structure. The first ring topological structure is formed by a plurality of first inverters connected end to end and configured to transmit an oscillation signal at a first transmission speed; and the second ring topological structure is formed by a plurality of second inverters connected end to end and configured to transmit the oscillation signal at a second transmission speed. The first ring topological structure is electrically connected with the second ring topological structure, and the second transmission speed is less than the first transmission speed.