Capacitor-Less Oscillator Circuit with NTC Bias Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Low-power-consumption oscillators in existing technologies require multiple sub-blocks, leading to high overall power consumption and are temperature-sensitive due to the variability of capacitors, which affects frequency stability.
Innovation Solution
An oscillator circuit utilizing a negative-temperature-coefficient (NTC) bias current generating circuit and a set of oscillator sub-block circuits that share transistors, eliminating the need for capacitors and achieving temperature insensitivity through current reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple sub-blocks are used in the oscillator circuit, then the oscillator functionality is achieved, but the overall power consumption increases
Solution Approach 1:
The patent combines the bias current generating circuit with the oscillator sub-blocks by sharing transistors between them. Specifically, transistors in the oscillator sub-blocks also function as transistors in the NTC bias current generating circuit, merging two previously separate functional blocks into one integrated structure that achieves both bias generation and oscillation with reduced power consumption
Solution Approach 2:
The shared transistors perform multiple functions simultaneously: they operate as active devices in the oscillator sub-blocks to generate oscillation signals, and at the same time function as transistors in the NTC bias current generating circuit to provide temperature-compensated bias currents. This multi-functionality eliminates the need for separate dedicated bias circuitry
2Reliability
If capacitors are used in the oscillator circuit, then the oscillation frequency can be controlled, but the frequency varies tremendously due to capacitor characteristic variations
Solution Approach 1:
The patent extracts and eliminates the capacitor component from the oscillator circuit entirely. Instead of using traditional RC or LC oscillation mechanisms that require capacitors, the invention employs a capacitor-less oscillation mechanism based on transistor switching and NTC bias current control, thereby removing the source of frequency instability associated with capacitor variations
Solution Approach 2:
The patent changes the fundamental operating parameters of the oscillator by using NTC (negative temperature coefficient) bias currents to control the oscillation frequency. By varying the bias current parameters through temperature compensation mechanisms, the circuit achieves frequency control without relying on capacitor values, thus eliminating frequency drift caused by capacitor characteristic variations
3Reliability
If traditional oscillator architecture is used, then the oscillator functions properly, but the circuit is temperature-sensitive
Solution Approach 1:
The patent employs NTC (negative temperature coefficient) bias current generating circuits that produce currents with opposite temperature dependence to the PTC (positive temperature coefficient) characteristics of transistor threshold voltages and other parameters. By carefully designing the NTC current parameters, the circuit achieves temperature compensation where the NTC current variations counteract the PTC effects, maintaining stable oscillation frequency across temperature ranges
Solution Approach 2:
The NTC bias current generating circuit provides automatic temperature compensation feedback to the oscillator sub-blocks. As temperature changes affect the oscillator parameters, the NTC circuit generates compensating bias currents that automatically adjust to counteract these changes, creating a negative feedback loop that stabilizes the oscillation frequency against temperature variations
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 results in a compact, power-efficient oscillator circuit that is insensitive to temperature variations and reduces frequency drift, achieving optimal performance without the need for capacitors and minimizing power consumption.
Implementation Method 1
An oscillator circuit utilizes a negative-temperature-coefficient (NTC) bias current generating circuit and a set of oscillator sub-block circuits that share transistors
Data Source
AI summary
The present invention provides an oscillator circuit and associated oscillator device. The oscillator circuit comprises a negative-temperature-coefficient (NTC) bias current generating circuit and a set of oscillator sub-block circuits. The NTC bias current generating circuit is coupled between a supply voltage and a ground voltage, and is arranged to generate at least one NTC bias current. The set of oscillator sub-block circuits are coupled to each other to form an oscillator. Each oscillator sub-block circuit of the set of oscillator sub-block circuits comprises a plurality of transistors coupled between the supply voltage and a node within the NTC bias current generating circuit, wherein the NTC bias current generating circuit and the aforementioned each oscillator sub-block circuit share at least one transistor in the plurality of transistors.