SLOS754C June 2012 – August 2016 DRV2603
Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.
The DRV2603 is designed to drive ERM and LRA actuators used for haptic feedback. ERM and LRA actuators can be used for numerous haptic feedback applications including vibration alerts, advanced vibration communication, button replacement, and tactile feedback for touch surface or screens.
The DRV2603 output is controlled using PWM input. The duty-cycle of the PWM determines the amplitude of the output waveform. By varying the duty cycle, advanced haptic patterns and sequences can be created such as click, bumps, pulses, ramps and many more.
If a PWM port is not available, the DRV2603 PWM pin can be controlled with a GPIO; however, the DRV2603 will only function as an ON-OFF driver. In the case of an ERM, when the GPIO is ON the output is 100% and when the GPIO is OFF the output is -100% (opposite direction). In the case of an LRA, when the GPIO is ON the output is 100% and when the GPIO is OFF the driver automatically brakes and will automatically bring the actuator to rest.
The DRV2603 supports both ERM and LRA actuators. The operating mode can be selected by pulling the LRA/ERM pin either HIGH or LOW. Figure 13 shows the LRA configuration and Figure 14 shows the ERM configuration.
This design assumes the values listed in Table 1.
|DESIGN PARAMETER||EXAMPLE VALUE|
|Actuator Type||ERM / LRA|
|Input Power Source||Battery|
The actuator decision is based on many factors including cost, form factor, vibration strength, power consumption requirements, haptic sharpness, reliability, and audible noise performance. The actuator selection is one of the most important design considerations of a haptic system and therefore the actuator should be the first component to consider when designing the system.
The following can be used to select the minimum required supply voltage.
A minimum supply current is also required based on the load. To ensure enough current can be sourced divide the supply voltage above by the load resistance in the actuator datasheet. Compare this number with the current capability of the battery or voltage supply.
The DRV2603 supports supply voltages from 2.5 to 5.2V. The DRV2603 can be directly connected to many battery types including common batteries like Lithium-Ion and Lithium-Polymer. The supply rejection feature of the DRV2603 eliminates the need for a voltage regulator between the battery and VDD.
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.