Oscillator Temperature Compensation Using Same-TCR Resistors
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Solution Overview
Problem
Conventional oscillators in semiconductor manufacturing technologies like FinFET face frequency variations due to temperature changes, as resistors with opposing temperature coefficients are not available on the same substrate, leading to inaccurate frequency outputs.
Innovation Solution
A Frequency Regulated Oscillator (FRO) circuit is designed with a resistor configuration that couples a frequency-to-voltage converter to a common gate amplifier, using resistors with matching temperature coefficients to cancel out temperature effects, thereby stabilizing the output frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistors with positive and negative temperature coefficients are used for temperature compensation, then frequency stability is improved, but manufacturing availability deteriorates
Solution Approach 1:
The patent changes the temperature coefficient parameter from mixed (positive and negative) to uniform (both positive), enabling manufacturing availability while maintaining temperature compensation through circuit topology and resistor ratio selection
Solution Approach 2:
The common-gate amplifier acts as an intermediary that transforms the temperature characteristics of resistors with the same temperature coefficient into a compensated frequency output, mediating between the resistors and the frequency signal
2Device complexity
If conventional RC oscillator design is used, then circuit simplicity is maintained, but frequency accuracy deteriorates
Solution Approach 1:
The patent introduces feedback mechanisms where the frequency-to-voltage converter and common-gate amplifier create a regulated loop that compensates for temperature-induced frequency variations, improving accuracy while maintaining reasonable complexity
Solution Approach 2:
The patent replaces the direct RC frequency determination with an electronic regulation system using frequency-to-voltage conversion and amplifier feedback, substituting a simple passive circuit with an active regulated system
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 FRO circuit significantly reduces frequency variation to less than ±1% across temperature and voltage changes, meeting precision demands in modern IC designs, particularly in FinFET technologies.
Implementation Method 1
a first resistor having a positive temperature coefficient of resistance and a second resistor having a negative temperature coefficient of resistance. The resistors may be arranged in a way such that the effects of temperature upon the latter cancel out opposing effects upon the former.
Data Source
AI summary
Systems and methods for providing temperature compensation in oscillators circuits are discussed. In various embodiments, these systems and methods may be implemented in technologies where only resistors with the same type (positive or negative) of temperature coefficients of resistance are available. For example, in some implementations, an oscillator circuit may include a voltage generator coupled to an input terminal of a common gate amplifier through a first resistor, and a frequency-to-voltage converter coupled to another input terminal of the common gate amplifier through a second resistor, where the second resistor may be configured to reduce a frequency variation of the oscillator circuit in response to temperature changes.