Maxim Integrated Products, Inc.

Qualcomm Incorporated

Synaptics Corporation

Syed Mahmud

Guozhong Shen

Ozan Ersan Erdogan

Ajay Taparia

Behrooz Javid

Rajesh Anantharaman

Rahim F Chowdhury

Kenneth W Knox

Philip Yiu Kwong Chan

Jean CauXuan Le

Jonathan Ku

Nan Wang

Rajesh Ananthararman

Low power input object settlement detection systems and methods for operating a capacitive sensor having a plurality, M, of transmitter electrodes and a plurality, N, of receiver electrodes, wherein N and M are integer values. A plurality of input object settlement scans are captured, when a presence of an input object is detected, or in response to a presence of an input object being detected, wherein capturing each input object settlement scan includes driving all or a portion of the plurality, M, of transmitter electrodes simultaneously and detecting receiver signals from at least a subset of the plurality, N, of receiver electrodes simultaneously. When a difference between subsequent input object settlement scans is below a threshold value, a full input object image is acquired.

Fast finger settlement detection for fingerprint sensors

Disclosed are systems and method for imaging an input object. An imaging device includes: a light source that emanates light to a sensing region in which the input object to be imaged is placed; a collimator filter layer; an image sensor array disposed below the collimator filter layer that blocks some light reflected from the input object while other light passes through apertures in the collimator filter layer and arrives at the image sensor array; and a controller configured to cause a first image of the input object to be captured with the light source turned on, and to transmit the first image to a processor associated with the electronic device to perform image matching against one or more template images before causing a second image of the input object to be captured with the light source turned off.

Optimized scan sequence for biometric sensor

An analog front end circuit utilizes coherent detection within a capacitance measurement application. The analog front end circuit uses coherent detection to measure capacitance of a touch screen display. An analog excitation signal is modulated by a capacitor to be measured. The modulated signal is synchronously demodulated using a correlator, which includes a discrete mixer and a discrete integrator. The excitation signal is also input to the mixer such that the modulated signal is multiplied by the excitation signal. The excitation signal is an analog signal having a sine wave function or other waveform.

Capacitive touch sense architecture having a correlator for demodulating a measured capacitance from an excitation signal

A system includes a signal generator and a correlator. The signal generator outputs a first signal to a first end of a capacitance to be measured. The correlator is connected to an output of the signal generator that outputs the first signal and to a second end of the capacitance. The correlator receives the first signal from the output of the signal generator and receives a second signal from the second end of the capacitance. The correlator correlates the first signal and the second signal and generates an output signal based on a correlation between the first signal and the second signal. The output signal is proportional to a capacitance value of the capacitance.

Continuous time correlator architecture

A touch panel sensor system that can dynamically measure noise and automatically switch to a frequency with minimal noise is described. The touch panel sensor system includes a sensor configured to detect a change in capacitance associated with a touch upon a touch panel. The system also includes a drive module configured to generate a drive signal having a first waveform characteristic (e.g., signal having a periodic waveform characteristic) during a first phase (e.g., sensor phase) and a second drive signal having a second waveform characteristic (e.g., constant voltage signal) during a second phase (e.g., noise detection phase). The first and second drive signals are configured to drive the sensor. The system also includes a measuring module coupled to the sensor that is configured to measure noise having the first waveform characteristic (e.g., periodic waveform characteristic) during the second phase.

Background noise measurement and frequency selection in touch panel sensor systems

Capacitance sensing circuits, systems and method can include sample and hold (S/H) circuits that can retain analog values for one set of capacitance sensors, and sequentially convert such analog values into digital values while analog values for another set of capacitance sensors values are generated.

Circuits, devices and methods having pipelined capacitance sensing

A mixed signal correlator utilizes coherent detection within a capacitance measurement application. In some applications, the mixed signal correlator is used to measure capacitance of a touch screen display. An external capacitor whose capacitance is measured is kept small for improved sensitivity and can be used for a variety of applications having varied integration periods for measurement. The external capacitor is kept small and can be used for varied applications by adjusting the output voltage within a range that is less than the supply voltage, and maintaining a count of the adjustments to later reconstruct an actual output voltage for the integration period. An output is a weighted sum of an analog integrator output and a digital counter output.

Calibration for mixed-signal integrator architecture

An analog front end circuit utilizes coherent detection within a capacitance measurement application. The analog front end circuit uses coherent detection to measure capacitance of a touch screen display. An analog excitation signal is modulated by a capacitor to be measured. The modulated signal is synchronously demodulated using a correlator, which includes an integrated mixing and integration circuit. The correlator includes a programmable impedance element that generates a time-varying conductance according to a controlling digitized waveform.

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Dublin, CA, United States of America

Syed Mahmud