DRV2603_14 Datasheet, PDF (10/19 Pages) Texas Instruments – Haptic Drive with Auto-Resonance Detection for Linear Resonance Actuators (LRA)

DRV2603
SLOS754A – JUNE 2012 – REVISED JANUARY 2014
www.ti.com
The full-scale, open-load output voltage of the DRV2603 in ERM mode is 3.6V. The output stage has a total
nominal R_DS of 1.9 Ω. When driving a 20 Ω ERM at full-scale, the differential voltage seen at the outputs is
approximately 3.3 V. When driving a 10 Ω ERM at full-scale, the output voltage is approximately 3.0 V.
The voltage seen at the outputs as a function of input duty cycle is given by this equation.
spacer
V V OUT = OUT (FULL-SCALE)
éInput Duty Cycle
êë
50
%
-
ù
1_úû
(2)
Since the DRV2603 includes constant output drive over supply voltage, the output PWM duty cycle will be
adjusted so that the relationship in the above equation will hold true regardless of the supply voltage. The output
duty cycle in ERM mode can be approximated by the following equation.
spacer
Output Duty Cycle (%) = ^{VOUT(FULL-SCALE)}
VDD
éInput Duty Cycle % ù
êë
50
- 1_úû 100%
(3)
EDGE RATE CONTROL
The DRV2603 output driver implements Edge Rate Control (ERC). This ensures that the rise and fall
characteristics of the output drivers do not emit levels of radiation that could interfere with other circuitry common
in mobile and portable platforms. Because of ERC, no output filter or ferrites are necessary.
DECOUPLING CAPACITOR
The DRV2603 has a switching output stage which pulls transient currents through the VDD pin. A 0.1 µF, low
equivalent-series-resistance (ESR) decoupling capacitor of the X5R or X7R type is recommended for smooth
operation of the output driver and the digital portion of the device.
SENDING A HAPTIC EFFECT
Sending a haptic effect with the DRV2603 is straightforward. The procedure is the same for both ERM and LRA
drive. The ERM/LRA pin should be tied high or low as shown in the system diagrams. Optimum performance is
achieved by using the following steps.
1. At or very near the same time, bring the EN pin high and start sourcing PWM waveform. No delays are
required. The best startup behavior is usually achieved when momentarily overdriving the actuator for 20 ms
to 50 ms. Reference the specifications of the actuator for optimum overdrive characteristics.
2. Change the PWM level as needed to achieve the desired effect.
3. When the effect is complete, set the PWM duty cycle to 0% if braking is desired. The EN pin must remain
high to actively brake the actuator. When braking is complete, set the EN pin low, concluding the haptic
effect. When braking an ERM, the user should take care not to brake the actuator for too long, or counter-
rotation can occur. When braking an LRA, the auto-resonance engine automatically drives the actuator to
zero vibration, so no significant reverse-phase vibration will ever occur.
10
Submit Documentation Feedback
Product Folder Links :DRV2603
Copyright © 2012–2014, Texas Instruments Incorporated