Magnetic Field Sensor Angle Detection Phase-Locked Loop
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Solution Overview
Problem
Existing magnetic field sensors face challenges in achieving high angular refresh rates and accuracy, particularly in applications where the magnetic field angle changes rapidly, due to limitations in processing output signals from angle sensing elements.
Innovation Solution
A magnetic field sensor system that includes a phase-locked loop (PLL) circuit to process output signals from multiple magnetic field sensing elements, such as vertical Hall Effect elements, to generate an angle signal with a high refresh rate. The PLL compares the phase of the measured magnetic field signal with a feedback signal, using a phase detector and a proportional-integral controller to minimize phase differences and provide an accurate angle signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional signal processing methods are used for angle sensing elements, then the device complexity remains low, but the angular refresh rate is limited and cannot achieve high speed detection
Solution Approach 1:
The patent implements a phase-locked loop (PLL) with feedback mechanism where the output signal is fed back through a divider and phase comparator to continuously adjust and lock onto the input signal phase. This feedback system enables high-speed angle detection by dynamically tracking rapid phase changes while maintaining system stability through closed-loop control.
Solution Approach 2:
The patent replaces conventional mechanical or simple electronic signal processing methods with a PLL-based system that uses phase detection and feedback control. This substitution enables higher angular refresh rates by utilizing electronic phase comparison and frequency division rather than traditional signal processing approaches.
2Speed
If the magnetic field angle changes rapidly, then the application requirements for speed increase, but the measurement accuracy deteriorates due to processing limitations
Solution Approach 1:
The PLL feedback mechanism continuously compares the phase of the divided output signal with the input signal, automatically adjusting to maintain accurate phase relationship even during rapid angle changes. This ensures high measurement accuracy is maintained despite increased detection speed requirements.
Solution Approach 2:
The patent employs a dynamic phase-locked system that can adapt to rapidly changing input conditions. The PLL continuously adjusts its output frequency and phase to match the input signal, enabling the system to maintain accuracy during dynamic, rapidly changing magnetic field conditions rather than being limited to static or slowly varying fields.
3Productivity
If a phase-locked loop is implemented to achieve high refresh rate, then the angular detection speed improves, but the device complexity increases
Solution Approach 1:
The PLL circuit performs multiple functions simultaneously: phase detection, frequency division, signal generation, and feedback control. By integrating these functions into a single unified system, the patent achieves high angular refresh rates without proportionally increasing overall device complexity, as the same circuit components serve multiple purposes in the angle detection process.
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 system achieves a high and constant angular refresh rate, improving the accuracy and speed of angle detection, even in rapidly changing magnetic field conditions, thereby enhancing performance in applications like motor control systems.
Implementation Method 1
The PLL compares the phase of the measured magnetic field signal with a feedback signal, using a phase detector and a proportional-integral controller to minimize phase differences
Implementation Method 2
A planar Hall element tends to be responsive to magnetic field perpendicular to a surface of a substrate on which the planar Hall element is formed. A vertical Hall element tends to be responsive to magnetic field parallel to a surface of a substrate on which the vertical Hall element is formed.
Data Source
AI summary
A magnetic field sensor includes a phase-locked loop to receive a measured magnetic field signal formed from sensing element output signals of a plurality of magnetic field sensing elements in response to a magnetic field. The phase-locked loop is configured to generate an angle signal having a value indicative of the angle of the magnetic field. Associated methods are also described.