5.2

Interfaces

5.2.1

PWM Interface

The PWM interface is a uni-directional interface with the angle information coded in the length of a pulse. The angle

value is proportional to the duty cycle of the output frequency. The duty cycle is calculated as the ratio of the “high”

time to the period length. An increasing angle results in an increased duty cycle with an angle of 0° having the

smallest duty cycle. The starting edge of the PWM protocol can be programmed as rising or falling edge. In case the

protocol starts with a rising edge (LOW level start), a pull-down resistor is required. For the start-up condition with a

falling edge (HIGH level start), a pull-up resistor instead has to be implemented. The protocol works in push/pull and

open drain configuration.

The tolerance of the programmed PWM frequency over temperature and lifetime is given in the table "PWM Frequency

tolerance".

The PWM protocol also allows to use the characteristic curves function, which is primarily utilized in chassis position

sensor applications. This function allows the measurement range of 360° to be divided into smaller segments of 90° or

120° (see Programmable measurement range), however the quadrant information is not transmitted.

 

Error indication

For diagnostic purpose and to indicate internal sensor failures, the output duty cycle of the PWM is limited. Within

this reserved lower and upper duty cycle range, no valid angle information is provided. Instead, this duty cycle range

is used for error indication with defined duty cycles which are clearly separated from the usable data duty cycle

range. The following events are indicated:

•

Occurrence of internal or external fault

•

Sensor reset occurred

 

Configuration

The PWM interface enables to configure the frequency, to define a data duty cycle range and a low and high value of

the diagnostic duty cycle. It has to be ensured by proper device configuration that there is no overlap of data duty

cycle range and low or high value of diagnostic duty cycle.

A possible and valid configuration is:

•

Data duty cycle: 12.5% ...87.5%:  the 12bit angle value is mapped to this duty cycle

•

Diagnostic duty cycle, low: 5%: Low diagnostic duty cycle for indicating firmware safety check errors, details

available in the TLE49SRPx safety manual

•

Diagnostic duty cycle, high: 95%: High diagnostic duty cycle for indicating hardware related errors, details

available in the TLE49SRPx safety manual

The PWM interface with data duty cycle range and reserved duty cycle for diagnostics is shown in figure "PWM

interface with duty cycle range starting with a rising edge".

TLE49SR

Datasheet

5  Specific module descriptions

Datasheet

16

Rev. 1.1.1

2024-03-13