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AS5134

Data Sheet - D e ta i l e d D e s c r i p t i o n

Digital Readout Rate

Aside from the chip-internal propagation delay, the time required to read and process the angle data must also be

considered. Due to its nature, a PWM signal is not very usable at high speeds, as you get only one reading per PWM

period. Increasing the PWM frequency may improve the situation but causes problems for the receiving controller to

resolve the PWM steps. The frequency on the AS5134 PWM output is typ. 1.95kHz with a resolution of 2µs/step. A

more suitable approach for high speed absolute angle measurement is using the serial interface. With a clock rate of

up to 6MHz, a complete set of data (21bits) can be read in >3.5µs.

Total Propagation Delay of the AS5134

The total propagation delay of the AS5134 is the delay in the analog signal path and the tracking rate of the ADC:

15.6µs + 1.4µs = 17µs

(EQ 2)

If only the SIN-/COS-outputs are used, the propagation delay is the analog signal path delay only (typ. 15.6µs).

Position Error Over Speed:

The angle error over speed caused by the propagation delay is calculated as:

(EQ 3)

In addition, the anti-aliasing filter causes an angle error calculated as:

Δ

(EQ 4)

Reduced Power Modes

The AS5134 can be operated in two reduced power modes. Both these modes have in common that they switch off or

freeze parts of the chip during intervals between measurements. In Low Power Mode or Ultra Low Power Mode, the

AS5134 is not operational, but due to the fast start-up, an angle measurement can be accomplished very quickly and

the chip can be switched to reduced power immediately after a valid measurement has been taken. Depending on the

intervals between measurements, very low average power consumption can be achieved using such a strobed

measurement mode.

Low/Mid Power Mode: Reduced current consumption, very fast start-up. Ideal for short sampling intervals (<3ms).

Power Cycling mode: Zero power consumption (externally switched off) during sampling intervals. Ideal for sam-

pling intervals 200ms.

Low/Mid Power Mode

The AS5134 can be put in Low/Mid Power Mode by simple serial commands, using the regular connection for 2-wire or

3-wire serial data transmission.

Table 9. Examples of the Overall Position Error caused by Speed (includes both propagation delay and filter delay)

Speed (rpm)

Total Position Error (

100

0,0175º

1000

0,175º

10000

1,75º