Battery-buffered 40-bit Hall multi-turn encoder

October 26, 2016 // By Julien Happich
The iC-PVL is a battery-buffered configurable Hall multi-turn encoder, drawing less than 10µA, allowing battery operation for several years. Designed in a 4x4mm² flat QFN package, the iC-PVL reads magnetic linear scales or tapes, or discs or magnet wheels with pole widths of 1.0 to 5.0mm.

The chip can be configured for linear applications as a pure period counter. In rotary applications, the FlexCount circuitry enables 1 to 256 magnetic pole pairs to be interpreted as one mechanical rotation. The position within the rotation (angle) can also be read out in this case. Rated for operation in the -40 to 125°C temperature range, the iC-PVL can read rotational velocities of up to 15 000 RPM (with a 32 pole-pair disc or wheel) or linear motion up to 24 m/s (with a 1.5 mm pole width scale or tape).

The device switches over to battery operation automatically when power fails and continues tracking the multi-turn count without disruption. A configurable battery voltage warning feature makes maintenance predictable and thus avoids downtime. The iC-PVL counts correctly despite low battery voltage, but indicates that the battery must be changed using both the error output and the status register. Current consumption in battery operation is configurable and can be adjusted for the maximum expected acceleration of the axis being tracked. The iC-PVL’s mode of operation is programmable. Depending on the configuration, position data is available as AB quadrature encoder signals or as a 3-bit parallel word and over SSI or I²C. The device can be operated by a microcontroller as an I²C slave with or without a battery. In this case an external EEPROM is unnecessary.

 

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