DRV2605L-Q1 Datasheet, PDF (27/67 Pages) Texas Instruments – Automotive Haptic Driver for LRA and ERM

www.ti.com
DRV2605L-Q1
SLOS874A – OCTOBER 2015 – REVISED OCTOBER 2015
Programming (continued)
7.5.7 Waveform Playback Programming
7.5.7.1 Data Formats for Waveform Playback
The DRV2605L-Q1 smart-loop architecture has three modes of operation. Each of these modes can drive either
ERM or LRA devices.
1. Open-loop mode
2. Closed-loop mode (unidirectional)
3. Closed-loop mode (bidirectional)
Each mode has different advantages and disadvantages. The DRV2605L-Q1 device brings new cutting-edge
actuator control with closed-loop operation around the back-EMF for automatic overdrive and braking. However,
some existing haptic implementations already include overdrive and braking that are embedded in the waveform
data. Open-loop mode is used to preserve compatibility with such systems.
The following sections show how the input data for each DRV2605L-Q1 interface is translated to the output drive
signal.
7.5.7.1.1 Open-Loop Mode
In open-loop mode, the reference level for full-scale drive is set by the OD_CLAMP[7:0] bit in Register 0x17. A
mid-scale input value gives no drive signal, and a less-than mid-scale gives a negative drive value. For an ERM,
a negative drive value results in counter-rotation, or braking. For an LRA, a negative drive value results in a 180-
degree phase shift in commutation.
The RTP mode has 8 bits of resolution over the I²C bus. The RTP data can either be in a signed (2s
complement) or unsigned format as defined by the DATA_FORMAT_RTP bit.
Steady-State
Output Magnitude
Open Loop
ERM_OPEN_LOOP = 1 OR LRA_OPEN_LOOP = 1
OD_CLAMP[7:0]
0V
-OD_CLAMP[7:0]
Input Interface
PWM
0%
RTP (8-bit) DATA_FORMAT_RTP = 0 0x81
RTP (8-bit) DATA_FORMAT_RTP = 1 0x00
Figure 25.
50%
0x00
0x7F
Input
100%
0x7F
0xFF
Copyright © 2015, Texas Instruments Incorporated
Product Folder Links: DRV2605L-Q1
Submit Documentation Feedback
27