Magnetic Sensor Pulse Control for Low Power Consumption
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Solution Overview
Problem
The power consumption of magneto-electric conversion elements in magnetic sensors has increased with the reduction in size of MR element films, and existing intermittent power supply control methods are limited by the operating speed and power consumption of external control components, making it difficult to further reduce the average consumption current.
Innovation Solution
A magnetic sensor that includes a pulse generator producing pulses with a width shorter than the external intermittent power supply's power-on time and a switch that controls the signal application time to the magneto-electric conversion element within the power-on time, reducing the power consumption by shortening the signal application time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the on-time of external intermittent power supply is shortened to reduce average consumption current, then power consumption decreases, but the operating speed and power consumption of external control components increase
Solution Approach 1:
The magnetic sensor generates its own internal pulse signal to control the power supply timing, eliminating the need for external control components. The pulse generator creates a pulse with width shorter than the external power supply's power-on time, and the switch uses this internal pulse to control the signal application time to the magneto-electric conversion element, making the system self-sufficient and removing the bottleneck of external control component performance
Solution Approach 2:
The system uses periodic pulsing of the power supply signal to the magneto-electric conversion element, where the pulse width is deliberately kept shorter than the external power supply's power-on time. This periodic action with optimized pulse width reduces the average consumption current while the internal pulse generator ensures the timing is precisely controlled without external component limitations
2Area of stationary object
If the area of MR element film is reduced to reduce sensor size, then sensor size decreases, but resistance value and power consumption increase
Solution Approach 1:
Instead of continuously powering the magneto-electric conversion element, the system applies power periodically through pulsed signals. The pulse width is optimized to be shorter than the external power supply's power-on time, reducing the duty cycle and thereby reducing the average power consumption of the MR element while maintaining its small area
Solution Approach 2:
The system changes the temporal parameters of power supply to the MR element by controlling the pulse width and pulse frequency. By adjusting these parameters, the average power consumption is reduced while the physical area of the MR element remains small, resolving the contradiction between size and power consumption
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 effectively reduces the overall power consumption of the magneto-electric conversion element by generating pulses internally to control the power supply, minimizing the power consumption and extending the on-time of the external intermittent power supply.
Implementation Method 1
a pulse generator that generates a pulse having a pulse width shorter than the power-on time of an intermittent power supply signal
Implementation Method 2
a switch that controls, based on the pulse, a signal application time of the intermittent power supply signal to the magneto-electric conversion element within the power-on time
Implementation Method 3
Each of magneto-electric conversion elements such as a Hall element and a magnetic resistance (MR) element is an element for detecting a magnetic field and converting it into an electrical signal
Data Source
AI summary
A magnetic sensor includes: a pulse generation circuit that generates a pulse having a pulse width shorter than the power-on time of an intermittent power supply signal from an external intermittent power supply; a magneto-electric conversion element; and a switch that controls, based on the pulse, a signal application time of the intermittent power supply signal to the magneto-electric conversion element within the power-on time. The magneto-electric conversion element is, for example, an MR element that outputs two detection signals, magnitude relation between signal levels of the two detection signals changing by field intensity of an external magnetic field. The magnetic sensor may further include an amplifier that amplifies the two detection signals and a comparator that compares the two amplified detection signals.