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AS5132

Datasheet - Detailed Descri p ti on

7.3.6 Multi Turn Counter

A 9-bit register is used for counting the magnet’s revolutions. With each zero transition in any direction, the output of a special counter is

incremented or decremented. The initial value after reset is 0 LSB. Clockwise rotation gives increasing angle values and positive turn count.

Counter clockwise rotation exhibits decreasing angle values and a negative turn count respectively.

The counter output can be reset by using command 20 – SET MT Counter. It is immediately reset by the rising clock edge of this bit. Any zero

crossing between the clock edge and the next counter readout changes the counter value.

7.3.7 High Speed Operation

The AS5132 is using a fast tracking ADC (TADC) to determine the angle of the magnet. The TADC is tracking the angle of the magnet with cycle

time of 2μs (typ. 1.4). Once the TADC is synchronized with the angle, it sets the LOCK bit in the status register. Once it is locked, it requires only

one cycle [2μs (typ. 1.4)] to track the moving magnet. The AS5132 can operate in locked mode at rotational speeds up to max.72,900 rpm.

7.3.8 Propagation Delay

The propagation delay is the time required from reading the magnetic field by the Hall sensors to calculating the angle and making it available on

the serial or PWM interface. While the propagation delay is usually negligible on low speeds, it is an important parameter at high speeds. The

longer the propagation delay, the larger becomes the angle error for a rotating magnet as the magnet is moving while the angle is calculated. The

position error increases linearly with speed.

7.3.9 Error Detection

The following errors are detected by the system:



Lock bit  the TADC has not yet found a valid angular position



AGC alarm  the AGC value is 63, magnetic field is too weak

By default, Lock bit error should activate the error condition at the outputs. The AGC alarm is permanently available at the DIAG pin.

Error condition at commutation and incremental outputs:



U, V and W outputs all ‘0’



A, B and I outputs all ‘1’