Oscillator Circuit Using Dual Reference Currents for Temperature Compensation
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Solution Overview
Problem
Existing oscillator designs face challenges in stabilizing frequency against temperature variations due to the lack of two temperature coefficient types of resistors, which are not available for cost-effective processes.
Innovation Solution
An oscillator device that compensates for temperature coefficient using a current generating circuit to generate multiple currents with different temperature coefficients, and a current source to create reference currents, allowing the oscillator circuit to generate an oscillating signal with stabilized frequency without requiring two types of temperature coefficient resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two temperature coefficient types of resistors are used to compensate for frequency variation, then frequency stability is improved, but manufacturing cost increases and component availability decreases
Solution Approach 1:
The patent changes the parameter type from resistance to current, using current sources with different temperature coefficients (positive and negative TC currents) to achieve temperature compensation. This eliminates the need for special temperature coefficient resistors while maintaining frequency stability across temperature variations.
Solution Approach 2:
The patent replaces the passive resistor-based temperature compensation mechanism with an active current-based compensation system. By using current sources and transconductance amplifiers, the system achieves temperature compensation through electrical parameter control rather than relying on physical resistor properties.
2Reliability
If two temperature coefficient types of resistors are used to compensate for frequency variation, then frequency stability is improved, but device complexity increases
Solution Approach 1:
The patent merges the temperature compensation function with the oscillation generation function by integrating the current sources into the oscillator circuit core. The same circuit blocks that generate oscillation also provide temperature compensation through their inherent temperature-dependent current characteristics, eliminating the need for separate compensation components.
Solution Approach 2:
The current sources in the oscillator circuit serve dual purposes: they generate the oscillation signal and simultaneously provide temperature compensation. The transconductance amplifiers and current mirrors perform multiple functions including signal generation, amplification, and temperature-dependent compensation within a unified circuit architecture.
Data Source
AI summary
An oscillator device includes a current generating circuit, a current source and an oscillator circuit. The current generating circuit generates first, second, third and fourth currents. The current source generates a first reference current according to the first current and the second current and a second reference current according to the third current and the fourth current. The oscillator circuit receives the first reference current and the second reference current and generates an oscillating signal. The temperature coefficient of the oscillator circuit is compensated for by the first reference current and the second reference current. At least two of the first current, the second current, the third current and the fourth current are different. The first reference current is different from the second reference current.