Open/Close switch

Development of open/close switches that excel in durability and reliability and are not affected by design reflects the recent trend toward diversification of electronic equipment, refrigerators, washing machines, etc.. Here, we provide an example of how to satisfy such requirements by combining the Hall effect IC and a magnet.

 

Position detection with a Hall effect IC

Advantages
1. High precision
   Accuracy of detection is high and design is simple due to the unique signal processing technology.
2. Extremely high sensitivity
   Sensitivity is very high, and it is possible to minimize the size of the magnet and increase flexibility for the mounting position.
3. Comprehensive choice
   We offer a range of types, including micro types, selectable polarity of magnetism detection, low−voltage driving types, etc.


Principle

On/off output can be obtained from a switch type Hall effect IC, depending on the intensity of the magnetic field. This is achieved by integrating a Hall element and an IC that converts the output of the Hall element into a digital signal.The Hall element outputs a voltage VΗ that is proportional to the external magnetic flux density B. This is a Hall effect IC that outputs on/off signals at the predetermined magnetic flux density B after processing the output of the Hall element through an amplifier and a reshaping circuit.

     [Distance between Hall effect IC and magnet]            [Magnetic flux density]

                        


Example of application

This is a typical switch type. Because it provides a variety of position detections and works across a wide range of supply voltage, it can be used in a variety of products, from refrigerators and washing machines to electronic equipment.

 

Door switch
Comprises one monopole magnet and one Hall element. This is a typical open/close switch and is very simple in construction.
Because magnetism is detected, the device is more resistant to tiny particles of dirt, dust, or oil and is not affected by the installation environment.

     [Drawers]                    [Refrigerator]       [Dish washer]

       


Cellular phone
The door switch application includes OPEN/CLOSE detection of the main LCD panel of the cellular phone. A variety of opening and closing methods can be achieved by combining Hall ICs with magnets.
Because no contact is involved in detection of the magnetic field, long−life durability is enhanced. Furthermore, leakage flux from the magnet is minimized because it operates with small magnetic flux density, and the magnetic effect on peripheral electronics, etc., can be minimized.

 

Recommended products for this application

Switch

 

Selection of composition and product

Recognizing that different customers will have different applications for Hall effect ICs, we undertake to provide proposals for optimum design based on magnetic simulation and measurement of various magnetic field−generating parts (magnetic noise).
In the design stage, we suggest appropriate magnets, Hall effect ICs and layouts. In the prototype production stage, we measure various parts in their actual mounted states.
 

About design of switches using Hall effect ICs

> Example of design for switches using Hall effect ICs

 

List of applications

Information devices such as cellular phones and notebook PCs, and household appliances such as refrigerators.

 

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