DA7280 datasheet(39/80 Pages) RENESAS

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DA7280-Automotive

Wideband LRA/ERM Haptic Driver for Automotive

Applications

Datasheet

Revision 1.4

01-Mar-2022

CFR0011-120-00

39 of 79

The timing of the sequence can be described as follows in Figure 20 where Amplitude X denotes

consecutive different output drive values:

Time [s]

OUTP

OUTN

POLARITY

OVERRIDE_VAL

I2C Update

Amplitude

Figure 20: Polarity Timing Relationship

5.7.9

Loop Filter Configuration

Haptic actuators (both ERM and LRA) can be modelled as a series combination of a resistor (Series

R) and inductor (Series L) followed by a BEMF voltage source, see Figure 21.

RSERIES

LSERIES

BEMF

Figure 21: Equivalent Electrical Model of an Actuator

The usual variation of RSERIES is from 8

Ω to 50 Ω and LSERIES is from 20 µH to either 2 mH or 3 mH.

The current regulation loop in the output drive must be kept stable by applying the correct setting in

the loop's filter. While the defaults cover the vast majority of available LRAs and ERMs further tuning

is possible by adjusting LOOP_FILT_CAP_TRIM, LOOP_FILT_RES_TRIM, and

LOOP_FILT_LOW_BW.

For LOOP_FILT_CAP_TRIM apply the settings in Table 14.

Table 14: LOOP_FILT_CAP_TRIM Register Trim Settings

Actuator

Series Resistance (Ω)

< 18

18 to 28

28 to 41

> 41

LOOP_FILT_CAP_TRIM

DA7280 Datasheet(PDF) 39 Page - Renesas Technology Corp