AS5147 datasheet(21/35 Pages) AMSCO

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ams Datasheet: 2014-Jun-27 [v1-04]

AS5147 – 21

Detaile d Desc rip t ion

Hysteresis

The hysteresis can be programmed in the HYS bits of the

SETTINGS register. The hysteresis can be 1, 2, or 3 LSB bits, in

which the LSB is defined by the ABI resolution setting (ABIRES).

Figure 35:

Hysteresis Settings

Automatic Gain Control (AGC) and CORDIC

Magnitude

The AS5147 uses AGC to compensate for variations in the

magnetic field strength due to changes of temperature, air gap

between the chip and the magnet, and demagnetization of the

magnet. The automatic gain control value can be read in the

AGC field of the DIAAGC register. Within the specified input

magnetic field strength (Bz), the Automatic Gain Control keeps

the CORDIC magnitude value (MAG) constant. Below the

minimum input magnetic field strength, the CORDIC

magnitude decreases and the MAGL bit is set.

Diagnostic Features

The AS5147 supports embedded self-diagnostics.

MAGH: magnetic field strength too high, set if AGC = 0x00. This

indicates the non-linearity error may be increased.

MAGL: magnetic field strength too low, set high if AGC = 0xFF.

This indicates the output noise of the measured angle may be

increased.

COF: CORDIC overflow. This indicates the measured angle is not

reliable.

LF: offset compensation completed. At power-up, an internal

offset compensation procedure is started, and this bit is set

when the procedure is completed.

HYS

HYSTERESIS with 11BIT ABI

Resolution

HYSTERESIS with 10BIT ABI

Resolution

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