4

AK Protocol

TLE5046iC-AK-LR and TLE5046iC-AK-ERR devices are compliant with: “Requirement Specifications for

Standardized Interface for Wheel Speed Sensors with Additional Information ‘AK-Protocol’ Version: 4.0” dated

13.02.2008 of Daimler AG, unless otherwise stated in this document or in the valid Technical Datasheets.

The following illustration defines the meaning of the data protocol. The bits 0 - 8 in the illustration are

designated as the data protocol and their purpose is to transfer additional information to the speed pulse.

Bit position #0 can be used as an indication for air gap reserve (LR), or can be interpreted by the ECU as an

“error bit” and treated in a special way (ERR). The two different variants TLE5046iC-AK-LR and TLE5046iC-AK-

ERR, respectively, perform accordingly.

Figure 4

Data protocol

5

Safety Mechanisms

The TLE5046iC offers safety features to support the Automotive Safety Integrity Level ASIL B and is designed to

be used in ASIL D systems.

An embedded safety concept was developed to notify the Control System in case of an internal error by setting

An embedded safety concept was developed to minimize the effect of hard and soft random errors by the

introduction of specific safety mechanisms. In case of an internal error a notification to the ECU is transmitted

via the protocol.

Following safety mechanisms have been implemented:

•

Undervoltage detection: This safety mechanism detects voltage drops to values where the correct

functionality of the circuitry is no more ensured. The sensor remains in this state until the error condition is

•

Detection of discrepancy between number of active fuses and internally stored number of fuses: This safety

mechanism compares the active fuse bits against the internal stored quantity. The sensor remains in this

present any longer.

•

Detection of clock malfunction: This safety mechanism forces the failure indication state if the clock is

either stuck or below 25% of the nominal value

•

Detection of different numbers between speed and direction path: This safety mechanism verifies if more

than two consecutive electric events are generated without any detected event in the direction path or vice

versa

•

Detection of critical air gap, ADC clipping and temperature monitoring: This safety mechanisms verifies

critical states inside the ASIC itself.

TLE5046iC

Technical product description

4 AK Protocol

Technical Product Description

8

Revision 2.0

2020-06-30