AS5045-ASST datasheet(31/47 Pages) AMSCO

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[v2-01] 2017-Jul-13

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AS5045 − Detailed Description

Failure Diagnostics

The AS5045 also offers several diagnostic and failure detection

features:

Magnetic Field Strength Diagnosis

By Software: The MagINC and MagDEC status bits will both be

high when the magnetic field is out of range.

By Hardware: Pins #1 (MagINCn) and #2 (MagDECn) are

open-drain outputs and will both be turned on (= low with

external pull-up resistor) when the magnetic field is out of

range. If only one of the outputs are low, the magnet is either

moving towards the chip (MagINCn) or away from the chip

(MagDECn).

Power Supply Failure Detection

By Software: If the power supply to the AS5045 is interrupted,

the digital data read by the SSI will be all “0”s. Data is only valid,

when bit OCF is high, hence a data stream with all “0”s is invalid.

To ensure adequate low levels in the failure case, a pull-down

resistor (~10k

Ω) should be added between pin DO and VSS at

the receiving side.

By Hardware: The MagINCn and MagDECn pins are open drain

outputs and require external pull-up resistors. In normal

operation, these pins are high ohmic and the outputs are high

(see Figure 15). In a failure case, either when the magnetic field

is out of range of the power supply is missing, these outputs

will become low. To ensure adequate low levels in case of a

broken power supply to the AS5045, the pull-up resistors

(~10k

Ω) from each pin must be connected to the positive

supply at pin 16 (VDD5V).

By Hardware, PWM Output: The PWM output is a constant

stream of pulses with 1kHz repetition frequency. In case of

power loss, these pulses are missing.

AS5045-ASST Datasheet(PDF) 31 Page - ams AG