Pixart Imaging Incorporated

Avago Technologies Ecbu IP (singapore) Pte. Ltd.

Avago Technologies General IP (singapore) Pte. Ltd.

Abhay Kumar Rai

Michael John Brosnan

Vitali Souchkov

Ronald Dean Gillingham

Jeffrey Stone

Shaik Hameed Anantapur

Seng Yee Chua

Disclosed are various embodiments of circuitry and methods for generating interpolated signals in an optical encoder. The optical encoder configurations and circuitry disclosed herein permit very high resolution reflective optical encoders in small packages to be provided. Methods of making and using such optical encoders are also disclosed. According to one embodiment, the interpolated signals are generated through the use of signal generation circuitry, peak voltage generation circuitry, reference voltage generation circuitry, slope detection circuitry, and a clocked comparator that is configured to output interpolated output pulses.

Interpolation circuitry for optical encoders

Various embodiments of methods and devices are provided for a mutual capacitance touchscreen controller comprising a first on-chip low drop out regulator (LDO) configured to receive and regulate as a first input thereto an input supply voltage (VSUPPLY), and to provide as an output therefrom a first regulated output voltage (VDDA). A first comparator in the controller is configured to receive as first and second inputs thereto VSUPPLY and VDDA and to provide as an output therefrom a signal EN, EN being provided to the first LDO as a second input thereto. The first LDO is configured to operate in a first off mode and is turned off by signal EN when the difference between VSUPPLY and VDDA is less than a predetermined threshold.

On-chip power-down generation for LDO-based mutual capacitance touchscreen controllers

Various embodiments of charge pump circuitry configured to generate output signals having first distortion signals superimposed thereon are disclosed. Demodulator input signals are also disclosed that have second distortion signals superimposed thereon. A synchronization signal is delivered to demodulator circuitry through at least first and second integer divider circuits and to charge pump circuitry through at least the first integer divider circuitry such that the first and second distortion signals have frequencies that are integer divisions of the synchronization frequency.

Charge pump frequency selection in touch screen sensor interface system

An apparatus for slew rate control using a plurality of discrete slew rate levels. The apparatus includes a load switch and a switch controller. The load switch outputs a load voltage to a load. The switch controller generates a switch control signal in response to an enable signal. The switch control signal controls operation of the load switch. The switch controller controls a slew rate of the load switch according to a plurality of discrete slew rate levels.

Slew rate control for a load switch

An encoder with signal conditioning of an emitter drive signal is described. In one embodiment, the encoder includes a peak comparator, a pulse generator, a threshold comparator, and digital circuitry. The peak comparator outputs a peak comparator signal based on a comparison of an input sinusoidal signal stored at a first time with the input sinusoidal signal stored at a second time. The pulse generator determines a peak of the input sinusoidal signal based on the peak comparator signal. The threshold comparator compares a differential signal amplitude with a differential signal amplitude window at approximately the peak of the input sinusoidal signal. The differential signal amplitude is associated with the input sinusoidal signal. The digital circuitry generates an emitter modification signal in response to a determination that the differential signal amplitude is outside of the differential signal amplitude window.

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Fort Collins, CO, United States of America

Abhay Kumar Rai