Abstract: An apparatus includes an oscillator circuit that may generate a clock signal with a frequency that is based on a voltage level of a control node, and a charge pump circuit that includes a first current source and a second current source. The first current source may be coupled between a first supply node and a first circuit node. The second current source may be coupled between a second supply node and a second circuit node. The charge pump circuit may be configured to pre-charge the first and second circuit nodes to voltage levels that differ from the control node and the first and second supply nodes. In addition, the charge pump circuit may select, based on phase information, either the first or second circuit node, and then modify, based on a voltage level of the selected circuit node, a voltage level of the control node.

Abstract: A capacitive fingerprint sensor includes an array of capacitive sensing elements, readout circuitry electrically coupled to the array of capacitive sensing elements, a block first digital to analog converter (DAC), at least one second DAC, and at least one summing junction electrically coupled to the readout circuitry, the first DAC, and the at least one second DAC. The readout circuitry is adapted to read out pixel voltages from a group of each block of capacitive sensing elements. The first DAC is adapted to provide a block baseline voltage for each block of capacitive sensing elements. The second DAC is adapted to provide a pixel baseline voltage difference for one capacitive sensing element of each group of each block. The summing junction is adapted to subtract the received block baseline voltage and the received pixel baseline voltage difference from the corresponding pixel voltage of each row of each block.

Abstract: An electronic device may include finger biometric sensing pixels and a processor capable of cooperating with the finger biometric sensing pixels to generate a series of finger images at a progressively slower capture rate as a finger settling increases over time from initial placement of a user's finger adjacent the finger biometric sensing pixels. The processor may also be capable of cooperating with the finger biometric sensing pixels to determine a quality factor for each image in the series thereof, and select at least one image from the series thereof for matching and based upon the quality factor.

Abstract: An electronic device may include finger biometric sensing pixels and a processor capable of cooperating with the finger biometric sensing pixels to generate a series of finger images at a progressively slower capture rate as a finger settling increases over time from initial placement of a user's finger adjacent the finger biometric sensing pixels. The processor may also be capable of cooperating with the finger biometric sensing pixels to determine a quality factor for each image in the series thereof, and select at least one image from the series thereof for matching and based upon the quality factor.

Abstract: A finger biometric sensing device may include drive circuitry capable of generating a drive signal and an array of finger biometric sensing pixel electrodes cooperating with the drive circuitry and capable of generating a detected signal based upon placement of a finger adjacent the array of finger biometric sensing pixel electrodes. The detected signal may include a relatively large drive signal component and a relatively small sense signal component superimposed thereon. The finger biometric sensing device may also include a gain stage coupled to the array of finger biometric sensing pixel electrodes, and drive signal nulling circuitry coupled to the gain stage capable of reducing the relatively large drive signal component from the detected signal.

Abstract: A finger biometric sensing device may include an array of finger biometric sensing pixel electrodes and a gain stage coupled to the array of finger biometric sensing pixel electrodes. The finger biometric sensing device may also include error compensation circuitry that may include a memory capable of storing error compensation data. The error correction circuitry may also include a digital-to-analog converter (DAC) cooperating with the memory and coupled to the gain stage and capable of compensating for at least one error based upon the stored error compensation data.

Abstract: A finger biometric sensing device may include drive circuitry capable of generating a drive signal and an array of finger biometric sensing pixel electrodes cooperating with the drive circuitry and capable of generating a detected signal based upon placement of a finger adjacent the array of finger biometric sensing pixel electrodes. The detected signal may include a relatively large drive signal component and a relatively small sense signal component superimposed thereon. The finger biometric sensing device may also include a gain stage coupled to the array of finger biometric sensing pixel electrodes, and drive signal nulling circuitry coupled to the gain stage capable of reducing the relatively large drive signal component from the detected signal.

Abstract: A finger biometric sensing device may include drive circuitry capable of generating a drive signal and an array of finger biometric sensing pixel electrodes cooperating with the drive circuitry and capable of generating a detected signal based upon placement of a finger adjacent the array of finger biometric sensing pixel electrodes. The detected signal may include a relatively large drive signal component and a relatively small sense signal component superimposed thereon. The finger biometric sensing device may also include a gain stage coupled to the array of finger biometric sensing pixel electrodes, and drive signal nulling circuitry coupled to the gain stage capable of reducing the relatively large drive signal component from the detected signal.

Abstract: A finger biometric sensing device may include an array of finger biometric sensing pixel electrodes and amplifiers coupled together in series and to be selectively coupled to respective ones of the array of finger biometric sensing pixels. The finger biometric sensing device may further include at least one coupling capacitor between an output of a given amplifier and a corresponding input of a next amplifier of the plurality thereof, and reset circuitry capable of selectively resetting the input of the next amplifier.

Abstract: An electronic device may include an array of finger sensing pixels and data acquisition circuitry coupled to the array. The data acquisition circuitry may be capable of acquiring finger biometric data from each sub-array of the array, and acquiring spoof detection data from at least one of the sub-arrays in an interleaved fashion with the finger biometric data.

Abstract: A finger biometric sensing device may include an array of finger biometric sensing pixel electrodes and amplifiers coupled together in series and to be selectively coupled to respective ones of the array of finger biometric sensing pixels. The finger biometric sensing device may further include at least one coupling capacitor between an output of a given amplifier and a corresponding input of a next amplifier of the plurality thereof, and reset circuitry capable of selectively resetting the input of the next amplifier.

Abstract: A finger sensing device may include an array of finger sensing pixels to receive a user's finger adjacent thereto. Each finger sensing pixel may include a finger sensing electrode. The finger sensing device may include a finger drive electrode configured to couple a drive signal through the user's finger to the array of finger sensing pixels. The finger sensing device may also include differential pixel measurement circuitry coupled to the array of finger sensing pixels and configured to generate a plurality of interpixel difference measurements for adjacent pairs of the finger sensing pixels.

Abstract: A finger biometric sensing device may include drive circuitry capable of generating a drive signal and an array of finger biometric sensing pixel electrodes cooperating with the drive circuitry and capable of generating a detected signal based upon placement of a finger adjacent the array of finger biometric sensing pixel electrodes. The detected signal may include a relatively large drive signal component and a relatively small sense signal component superimposed thereon. The finger biometric sensing device may also include a gain stage coupled to the array of finger biometric sensing pixel electrodes, and drive signal nulling circuitry coupled to the gain stage capable of reducing the relatively large drive signal component from the detected signal.

Abstract: A finger sensing device may include an array of finger sensing pixels to receive a user's finger adjacent thereto. Each finger sensing pixel may include a finger sensing electrode. The finger sensing device may include a finger drive electrode configured to couple a drive signal through the user's finger to the array of finger sensing pixels. The finger sensing device may also include differential pixel measurement circuitry coupled to the array of finger sensing pixels and configured to generate a plurality of interpixel difference measurements for adjacent pairs of the finger sensing pixels.

Abstract: An automatic gain control (AGC) amplifier including a high gain transimpedance amplifier, a resistive feedback network and multiple transconductance stages coupled in the feedback path of the AGC amplifier. The feedback network receives an input signal and is coupled to the output of the high gain amplifier and has multiple intermediate nodes. Each transconductance stage has an input coupled to an intermediate node of the feedback network and an output coupled to the input of the high gain amplifier. Each transconductance stage is independently controllable to position a virtual ground within the feedback network to control closed loop gain. Each transconductance stage may have a bias current input coupled to a bias current control circuit. The control circuit controls each bias current to vary the gain of the AGC amplifier. The bias currents may be linearly controlled employing a ramp function to achieve a linear in dB gain response.

Abstract: A calibrated DC compensation system for a wireless communication device configured in a zero intermediate frequency (ZIF) architecture. The device includes a ZIF transceiver and a baseband processor, which further includes a calibrator that periodically performs a calibration procedure. The baseband processor includes gain control logic, DC control logic, a gain converter and the calibrator. The gain converter converts gain between the gain control logic and the DC control logic. The calibrator programs the gain converter with values determined during the calibration procedure. The gain converter may be a lookup table that stores gain conversion values based on measured gain of a baseband gain amplifier of the ZIF transceiver. The gain control logic may further include a gain adjust limiter that limits change of a gain adjust signal during operation based on a maximum limit or on one or more gain change limits.

Abstract: An electrostatic discharge (ESD) switch circuit for an integrated circuit (IC) with multiple power inputs for improving pin-to-power isolation of the IC. The IC includes a plurality of positive power pins and a corresponding plurality of negative power pins. The IC also includes an ESD ring network with a high ESD bus and a low ESD bus. The IC further includes a control circuit indicating one of several operational modes. The ESD switch circuit includes a first switch circuit that couples the high ESD bus to a first positive power pin in a first operational mode and that couples the high ESD bus to a second positive power pin in a second operational mode. The ESD switch circuit further includes a second switch circuit that couples the low ESD bus to a first negative power pin in the first operational mode and that couples the low ESD bus to a second negative power pin in the second operational mode.

Abstract: A wireless communication device including a radio frequency (RF) circuit, a ZIF transceiver and a baseband processor. The ZIF transceiver includes an RF mixer circuit that converts the RF signal to a baseband input signal, a summing junction that subtracts a DC offset from the baseband input signal to provide an adjusted baseband input signal, and a baseband amplifier that receives the adjusted baseband input signal and that asserts an amplified input signal based on a gain adjust signal. The baseband processor includes gain control logic, DC control logic and a gain interface. The gain control logic receives the amplified input signal, estimates input signal power and asserts the gain adjust signal in an attempt to keep the input signal power at a target power level. The DC control logic estimates an amount of DC in the amplified input signal and provides the DC offset in an attempt to reduce DC in the amplified input signal.

Abstract: An automatic gain control (AGC) circuit including a high gain amplifier, a feedback network and two transconductance amplifiers. The feedback network has a first end that receives an input signal of the AGC circuit, a second end coupled to the output of the high gain amplifier and two intermediate nodes. Each transconductance amplifier has an input coupled to a respective intermediate node of the feedback network and an output coupled to the input of the high gain amplifier. The transconductance amplifiers collectively control a position of a virtual ground within the feedback network to control gain of the AGC circuit. The transconductance amplifiers each include an attenuator and a transconductance stage coupled between the feedback network and the high gain amplifier and are configured to operate linearly across a relatively wide input voltage range. The input offset voltage of the AGC circuit varies monotonically with gain of the AGC circuit.

Abstract: An automatic gain control (AGC) circuit including a high gain amplifier, a feedback network and two transconductance amplifiers. The feedback network has a first end that receives an input signal of the AGC circuit, a second end coupled to the output of the high gain amplifier and two intermediate nodes. Each transconductance amplifier has an input coupled to a respective intermediate node of the feedback network and an output coupled to the input of the high gain amplifier. The transconductance amplifiers collectively control a position of a virtual ground within the feedback network to control gain of the AGC circuit. The transconductance amplifiers each include an attenuator and a transconductance stage coupled between the feedback network and the high gain amplifier and are configured to operate linearly across a relatively wide input voltage range. The input offset voltage of the AGC circuit varies monotonically with gain of the AGC circuit.