DRV2605L Datasheet, PDF (42/69 Pages) Texas Instruments – DRV2605L 2 to 5.2 V Haptic Driver for LRA and ERM With Effect Library and Smart-Loop Architecture

DRV2605L
SLOS854C – MAY 2014 – REVISED SEPTEMBER 2014
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8.6.17 Overdrive Clamp Voltage (Address: 0x17)
Figure 46. Overdrive Clamp Voltage Register
7
R/W-1
6
R/W-0
5
R/W-0
4
3
OD_CLAMP[7:0]
R/W-1
R/W-1
2
R/W-1
1
R/W-0
Table 20. Overdrive Clamp Voltage Register Field Descriptions
0
R/W-0
BIT FIELD
7
OD_CLAMP[7:0]
TYPE
R/W
DEFAULT
0x8C
DESCRIPTION
During closed-loop operation the actuator feedback allows the output voltage
to go above the rated voltage during the automatic overdrive and automatic
braking periods. This register sets a clamp so that the automatic overdrive is
bounded. This bit also serves as the full-scale reference voltage for open-loop
operation.
See the Overdrive Voltage-Clamp Programming section for calculating the
correct register value.
8.6.18 Auto-Calibration Compensation Result (Address: 0x18)
Figure 47. Auto-Calibration Compensation-Result Register
7
R/W-0
6
R/W-0
5
R/W-0
4
3
A_CAL_COMP[7:0]
R/W-0
R/W-1
2
R/W-1
1
R/W-0
0
R/W-0
Table 21. Auto-Calibration Compensation-Result Register Field Descriptions
BIT FIELD
7-0 A_CAL_COMP[7:0]
TYPE
R/W
DEFAULT
0x0C
DESCRIPTION
This register contains the voltage-compensation result after execution of auto
calibration. The value stored in the A_CAL_COMP bit compensates for any
resistive losses in the driver. The calibration routine checks the impedance of
the actuator to automatically determine an appropriate value. The auto-
calibration compensation-result value is multiplied by the drive gain during
playback.
Auto-calibration compensation coefficient = 1 + A_CAL_COMP[7:0] / 255
8.6.19 Auto-Calibration Back-EMF Result (Address: 0x19)
Figure 48. Auto-Calibration Back-EMF Result Register
7
R/W-0
6
R/W-1
5
R/W-1
4
3
A_CAL_BEMF[7:0]
R/W-0
R/W-1
2
R/W-1
1
R/W-1
0
R/W-1
Table 22. Auto-Calibration Back-EMF Result Register Field Descriptions
BIT FIELD
7-0 A_CAL_BEMF[7:0]
TYPE
R/W
DEFAULT
0x6F
DESCRIPTION
This register contains the rated back-EMF result after execution of auto
calibration. The A_CAL_BEMF[7:0] bit is the level of back-EMF voltage that the
actuator gives when the actuator is driven at the rated voltage. The DRV2605L
playback engine uses this the value stored in this bit to automatically determine
the appropriate feedback gain for closed-loop operation.
Auto-calibration back-EMF (V) = (A_CAL_BEMF[7:0] / 255) × 1.22 V /
BEMF_GAIN[1:0]
42
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