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AS5134

Datasheet - Application In form atio n

8.4.2 Digital Readout Rate

Apart from the chip-internal propagation delay, the chip requires time to read and process the angle data. Due to its nature, a PWM signal is not

usable at high speeds, as you get only one reading per PWM period. Increasing the PWM frequency improves it. But problems will occur at the

receiving controller to resolve the PWM steps. The frequency on the AS5134 PWM output is typical 1.33kHz 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.

8.4.3 Low Power Mode

The target of this mode is to reduce the long time power consumption of the device for battery powered applications, without losing the actual

angle information.

In Low Power Mode, the AS5134 is inactive. The last state (for 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. If the AS5134 is cycled between

active and reduced current mode, a substantial reduction of the average supply current can be achieved. The minimum dwelling time is <0.5 ms.

The actual active time depends on how much the magnet has moved while the AS5134 was in reduced power mode. The angle data is valid,

when the status bit LOCK has been set. Once a valid angle has been measured, the AS5134 can be put back to reduced power mode. The

average power consumption can be calculated as:

(EQ 2)

Where:

To access the Low Power Mode, the bit ‘LP’ <15> of the digital interface has to be set to “1”.

Figure 20. Low Power Mode Connection

add an RC-filter (R1/C1) to avoid peak currents at power supply. The value of R1 is set that it maintains a VDD voltage of 4.5V – 5.5V and

especially during long active periods the R1 must maintain the charge which C1 has expired. C1 can be set in such a way as it can support peak

currents during the active operation period. In case of long active periods, C1 has a great value and R1 has a small value.

+

+

---------------------------------------------------------------------

=

R1

AS5134

VDD

C1

C2

100nF

VSS

+5V

VDD

Micro

Controller

CS

DCLK

DIO

VSS

VSS

VDD

on/off

S

N