Micro Magnetic Sensor Linearity via Opposite Pulse Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rising pulse detection in GSR sensors suffers from inferior linearity compared to falling pulse detection, limiting its sensitivity and power efficiency, while existing methods struggle to isolate induced voltage from coil voltage effectively.
Innovation Solution
Arranging two magnetic wires in a coil with opposite pulse current directions allows for zero coil induced voltage at zero magnetic field, enabling detection of only the external magnetic field voltage with improved linearity and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rising pulse detection is used to reduce power consumption and increase sensitivity, then detection sensitivity is improved and power consumption is reduced, but linearity deteriorates to 1-2%
Solution Approach 1:
The coil is divided into two separate coils (first coil and second coil) wound in opposite directions around the magnetic wire. Each coil detects voltage independently, allowing the system to segment the detection process and cancel out unwanted induced voltages by combining signals from both coils.
Solution Approach 2:
The two coils are intentionally designed with asymmetric winding directions (one clockwise, one counterclockwise). This asymmetry causes the induced voltages from pulse current to have opposite polarities, enabling cancellation when signals are combined, while the magnetic field signal remains additive.
2Volume of moving object
If sensor size is reduced to provide in motion devices, then device integration is improved, but detection sensitivity deteriorates inversely proportional
Solution Approach 1:
The patent combines multiple functions into a single integrated structure: the magnetic wire serves as both the sensing element and the core around which coils are wound. The dual-coil configuration merges signal generation and signal detection functions in one compact assembly, maximizing sensitivity within minimal volume.
Solution Approach 2:
The patent optimizes critical parameters including coil pitch (distance between adjacent windings), coil diameter, and wire diameter to achieve maximum detection sensitivity in a minimized sensor volume. By carefully controlling these geometric parameters, the sensor maintains high sensitivity despite reduced overall size.
3Use of energy by stationary object
If pulse time is shortened to reduce power consumption, then power consumption is reduced, but the induced voltage from pulse current becomes harder to cancel
Solution Approach 1:
The patent creates a duplicate detection path using two coils wound in opposite directions. Each coil generates a copy of the detection signal, but with the pulse-induced voltage component having opposite polarity. By combining these copies, the unwanted induced voltage cancels out while the magnetic field signal reinforces, maintaining accuracy even with short pulse durations.
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 achieves five times higher magnetic field detection sensitivity with 1/10th the power consumption of traditional methods, enhancing the sensitivity and downsizing potential of GSR sensors for in-vivo motion devices.
Implementation Method 1
a ultra high-sensitivity micro magnetic sensor based on the GHz spin rotation effect
Implementation Method 2
the coil voltage occurred when the pulse current is applied to the magnetic wires in opposite directions
Implementation Method 3
the pulse current applied to the magnetic wire has a pulse frequency of 0.2 GHz to 4 GHz and a strength required to generate over a 1.5 times larger circumferential magnetic field than the magnetic anisotropy field on a surface of the wire
Data Source
Figure 1
Figure 2
Figure 3
AI summary
To achieve magnetic field sensitivity and linearity that are advantages of rising pulse detection while improving the linearity of the rising pulse detection to 0.5% or lower. On the basis of the knowledge that if two magnetic wires are provided for one coil and a pulse current is applied thereto in opposite directions, the coil induced voltage in rising pulse detection becomes zero, the pulse current applied to the magnetic wire having a magnetic anisotropy field of 20 G or less, with a two-phase magnetic domain structure of a surface magnetic domain with circumferential spin alignment and a center core magnetic domain with longitudinal spin alignment, has a pulse frequency of 0.2 to 4.0 GHz and a strength required to generate over a 1.5 times larger circumferential magnetic field than the anisotropy field on a surface of the wire. The coil has a coil pitch of 10 µm or less.