Shared Spiral Inductor Layout for Multi-Band On-Chip Oscillators
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Solution Overview
Problem
Conventional integrated circuits with multiple LC oscillators require separate inductors, which occupy significant device area and compromise power efficiency and phase noise performance due to the use of serial switches.
Innovation Solution
The implementation of a shared spiral inductor that can be tapped at different locations to form multiple LC circuits, allowing unused portions to be electrically isolated without using serial switches, thereby improving power consumption and phase noise performance while saving device area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate inductors are used for each LC oscillator, then each oscillator can operate independently, but device area is significantly increased
Solution Approach 1:
Multiple LC oscillators share a common spiral inductor structure, merging what would traditionally be separate inductor components into a single integrated element. The inductor has multiple taps at different locations along its conductive path, allowing each oscillator to access different inductance values from the same physical structure, thereby reducing overall device area while maintaining independent operation.
Solution Approach 2:
The shared spiral inductor serves multiple functions simultaneously by providing different inductance values to different oscillators through its tap points. A single inductor structure performs the role of multiple separate inductors, enabling the system to achieve frequency multiplication and band coverage without proportionally increasing component count or area.
2Adaptability or versatility
If serial switches are used in separate inductors, then frequency tuning is achieved, but power efficiency deteriorates and phase noise increases
Solution Approach 1:
The patent extracts and eliminates the serial switches from the inductor structure entirely. Instead of using switches to tune frequency by connecting/disconnecting inductor segments, the design uses direct tap points along the continuous conductive path of the spiral inductor. This removes the source of switch-induced power consumption and phase noise while preserving frequency tuning capability through selective tap activation.
Solution Approach 2:
The tap points serve as intermediary connection points along the inductor's conductive path, allowing oscillators to access different inductance values without requiring active switching elements. The continuous conductive structure with accessible taps provides a passive, low-loss method for frequency selection that mediates between the need for tuning and the desire for low power consumption.
3Reliability
If separate inductors are used for each oscillator, then each oscillator has dedicated components, but device area is consumed
Solution Approach 1:
The patent implements a nested structure where multiple oscillator circuits are integrated around a central shared inductor. Different oscillator cores are positioned to access different portions of the inductor through taps, creating a compact nested arrangement that maximizes component density while maintaining electrical isolation between oscillators when not in use.
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
This approach enables efficient use of device area, enhances power consumption, and reduces phase noise, allowing for multiple frequency bands to be achieved with improved performance compared to conventional designs.
Implementation Method 1
an inductor including a conductive path formed in an integrated circuit device
Data Source
AI summary
Some embodiments include apparatuses and methods of using the apparatuses. One of the apparatuses includes an inductor included in an integrated circuit device, and a first oscillator and a second oscillator included in the integrated circuit device. The first oscillator includes a first terminal coupled to a conductive path of the inductor to provide a first signal. The second oscillator includes a second terminal coupled to the conductive path to provide a second signal. The first and second signals have different frequencies.