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AS5130

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 AS5130 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 AS5130

The total propagation delay of the AS5130 is the delay in the analog signal path and the tracking rate of the ADC:

15.6µs + 1.15µs = 16.75µs

(EQ 4)

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 5)

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

Δ

(EQ 6)

Reduced Power Modes

The AS5130 can be operated in three reduced power modes. All three 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

AS5130 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 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, but slower start-

up than Polling Mode. Ideal for sampling intervals 200ms.

Polling Mode: for reduction of the average power consumption; especially suited for battery powered applications.

Low Power Mode

The AS5130 can be put in Low Power Mode by simple serial commands, using the regular SSI commands. The

required serial command is WRITE CONFIG (17H, Figure 3 on page 10). The angle data is valid, as soon as the

LOCK- Flag is 1 (see Table 8).

In Reduced Power Modes, the AS5130 is inactive. The last state, e.g. the angle, AGC value, etc. is frozen and the chip

starts from this frozen state when it resumes active operation. This method provides much faster start-up than a “cold

start” from zero.

Table 10. 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