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Micropower switches are integrated Hall-effect sensor ICs designed specifically for use in battery-operated devices, providing low power consumption for longer battery life. They are typically used for on/off switches (open/close) in cellular flip-phones, PDAs, and laptop computers, or for detecting motion or tampering in utility meters.
During operation (awake mode), these ICs compare the actual magnetic field detected with the internally compensated thresholds and switch the output on in the presence of sufficient magnetic field. During sleep mode, the output stage is latched. Current consumption is significantly reduced by cycling the awake and sleep periods.
The switching behavior of micropower switches is omnipolar, which means they can be switched on with either the North or South pole of a magnet.
Allegro offers unique 3D omnipolar sensor ICs that can detect magnetic fields of either polarity and in any direction. They are highly sensitive, making them ideal for detecting tampering via magnetic fields in applications such as smart meters, ATMs, gambling/gaming machines, ticket machines, electronic locks, etc. They can also be used as highly flexible proximity sensors, as they are insensitive to magnet orientation/direction.
Hall-effect latches are most comm in sensing multi-pole ring magnets for motor commutation, because they require a south pole of sufficient strength to turn the output on and a north pole of sufficient strength to turn the output off. These contactless senonly usedsing solutions require few external components and can withstand the hostile operating conditions of automotive applications.
This section includes products developed for very specific application needs. Please consult with your local Allegro Field Applications Engineer to confirm if one of these products is the best choice for your design.
Dual element devices are integrated circuits that contain two independent Hall-effect switches. The digital outputs are out of phase so that the outputs are in quadrature when interfaced with the proper ring magnet design (alternating pole ring magnet). This allows either the user to externally process the output signals to determine speed and direction of an encoder ring magnet or certain devices to internally process these signals and output speed and direction signals. Extremely low-drift amplifiers guarantee symmetry between the switches to maintain signal quadrature. The Allegro patented, high-frequency chopper-stabilization technique cancels offsets in each channel providing stable operation over the full specified temperature and voltage ranges.
Allegro MicroSystems, LLC offers a wide variety of lighting solutions. By combining industry-leading Hall-effect sensor technology with proven LED driver technology, Allegro offers LED lighting solutions for automotive, industrial, commercial, and consumer applications.
Littelfuse offers the widest selection of magnetically operated reed switches. Reed switches are available in bare glass or over-molded packages with a variety of mechanical, electrical, and magnetic characteristics. Options for customization, such as lead cutting and forming, are available.
With a broad range of reed sensor offerings, Littelfuse has the solutions for your proximity, level, speed and flow sensing needs. Our reed sensors employ the latest in reed switch technology, packaged in a variety of capsules suitable for mounting in a wide array of applications. Options for customization are available.