Texas Instruments Corporation

David Hernandez-Garduno

David John Baldwin

Mayank Garg

Mohammad A Al-Shyoukh

Brett Earl Forejt

Brandon J Beckham

A method for driving a Linear Resonant Actuator (LRA) is provided. During a first off interval, the back-emf of the LRA is measured. During a first off interval, a timer is started when the back-emf reaches a predetermined threshold, and after a predetermined delay has lapsed following the back-emf reaching the predetermined threshold during the first off interval, the LRA is driven over a drive interval having a length and drive strength. A second off interval is entered following the drive interval, and during the second off interval, the back-emf of the LRA is measured. During the second off interval, the timer is stopped when the back-emf reaches the predetermined threshold. The value from the timer that corresponds to the duration between the back-emf reaching the predetermined threshold during the first off interval and the back-emf reaching the predetermined threshold during the second off interval determines the length.

Method and apparatus to drive a linear resonant actuator at its resonant frequency

Multistage charge pumps with diode loss compensation are disclosed. In one example, a pre-regulated charge pump to generate a voltage is described. The example pre-regulated charge pump includes a charge pump having a plurality of stages and one or more diodes. The stages are configured to generate an output voltage at an output terminal based on an input voltage and a number of the multiplier stages. The example pre-regulated charge pump also includes a pre-regulator stage configured to adjust the input voltage to remove dependency on supply voltage variation. The pre-regulator includes a feedback diode configured to compensate for one or more voltage drops associated with the one or more charge pump diodes.

Growing community of inventors

Dallas, TX, United States of America

David Hernandez-Garduno