Current-Controlled Oscillator Using One Comparator for Accurate Duty Cycle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional current-controlled oscillators require multiple current sources and comparators, leading to high power consumption and large area occupancy, with duty cycle accuracy compromised by mismatches in these components.
Innovation Solution
A current-controlled oscillator design utilizing a single comparator and a single current source in the frequency generation path, with capacitors controlling the duty cycle, reducing power consumption and area while maintaining high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional architecture with two current sources and two comparators is used, then the oscillator can generate clock signals, but power consumption and area occupancy increase significantly
Solution Approach 1:
The patent merges the functions of two comparators into a single comparator by using a single frequency-generation path. The comparator compares the voltage across a switched capacitor against a reference voltage, eliminating the need for duplicate comparator circuits and reducing power consumption while maintaining oscillation functionality.
Solution Approach 2:
The single comparator in the patent serves multiple functions: it determines the oscillation frequency by comparing capacitor voltage against reference, generates the oscillating signal, and controls the switching of capacitors. This multi-functional approach replaces the traditional architecture where two comparators performed similar functions independently.
2Area of stationary object
If traditional architecture with two current sources is used, then the oscillator can maintain frequency, but area occupancy increases for low cost designs
Solution Approach 1:
The patent combines the frequency-determining function into a single capacitor and single comparator circuit, eliminating the need for two separate current sources. The switched capacitor configuration allows one current source to control the charging/discharging cycles that determine oscillation frequency, reducing area occupancy while maintaining frequency stability.
3Manufacturing precision
If two comparators are used in traditional architecture, then frequency generation is achieved, but duty cycle accuracy deteriorates due to component mismatches
Solution Approach 1:
By using a single comparator to determine the oscillation frequency through voltage comparison against a reference, the patent eliminates mismatches between two comparators that would otherwise cause duty cycle variations. The single comparator ensures consistent threshold comparison, improving duty cycle accuracy to within 0.5% variation.
4Manufacturing precision
If two current sources with precise matching are used, then duty cycle accuracy improves, but power consumption and area increase
Solution Approach 1:
The patent achieves high duty cycle accuracy (within 0.5% variation) by using a single comparator and single current source configuration, eliminating the need for precisely matched pairs of components. The single comparator compares voltage against a reference threshold, ensuring accurate frequency determination without requiring component matching, thereby reducing power consumption and area.
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 design achieves significantly reduced power consumption and area, with duty cycle accuracy improved to within 0.5% variation, compared to 5% in traditional designs, and operates efficiently at various frequencies.
Implementation Method 1
capacitor 111, capacitor 112
Data Source
AI summary
A current-controlled oscillator receives an input current. Ramp voltage generating circuitry generates first and second ramp voltages in response to the input current. Selecting circuitry selects one of the first and second ramp voltages depending on their relative values. Switching circuitry receives a selected ramp voltage, generates a signal based on the selected ramp voltage relative to a reference voltage, and outputs a clock signal. In one embodiment, a comparator receives the reference voltage, one of the first and second ramp voltages, and outputs a comparison signal. Logic circuitry controls the ramp voltage generating circuitry to output one of the ramp voltages during one half of a clock cycle and to output the other ramp voltage during another half cycle of the clock signal based on the comparison signal and logic states of the logic circuitry.