Abstract: An apparatus for reducing noise in fingerprint sensing circuits is disclosed in one embodiment of the invention as including a fingerprint sensing area onto which a user can apply a fingerprint. An analog front end is coupled to the fingerprint sensing area and is configured to generate an analog response signal. An analog-to-digital converter (ADC) samples the analog response signal and converts the sample to a digital value, which may be received by a digital device such as a processor or CPU. To reduce the amount of the noise that is present in the analog response signal and therefore reflected in the digital value, the digital device may be shut down while the ADC is sampling the analog response signal.

Abstract: An apparatus for culling substantially redundant data in a fingerprint sensing circuit is disclosed in one embodiment of the invention as including an input module, a storage module, a comparator module, and a determination module. The input module may receive sets of data samples from an array of fingerprint sensing elements. The sets of data samples may be stored by the storage module. The comparator module may calculate a difference between each data sample from a first-received set, and a corresponding data sample from a second-received set. The determination module may count the number of difference values that exceed a predetermined difference limit, and identify the second set of data samples as redundant if the number of difference values counted is less than a pre-set count limit.

Abstract: An apparatus and method for detecting the presence of a finger on a fingerprint sensor is disclosed in one embodiment of the invention as including transmitting a probing signal, comprising a series of probing pulses, to a fingerprint sensing area. A response signal, comprising a series of response pulses, is received from the fingerprint sensing area in response to the probing signal. An upper reference signal is generated and finger activity is detected on the fingerprint sensing area by monitoring whether the peaks of the response pulses exceed the reference signal.

Abstract: An apparatus for reducing noise in fingerprint sensing circuits is disclosed in one embodiment of the invention as including a fingerprint sensing area onto which a user can apply a fingerprint. An analog front end is coupled to the fingerprint sensing area and is configured to generate an analog response signal. An analog-to-digital converter (ADC) samples the analog response signal and converts the sample to a digital value, which may be received by a digital device such as a processor or CPU. To reduce the amount of the noise that is present in the analog response signal and therefore reflected in the digital value, the digital device may be shut down while the ADC is sampling the analog response signal.

Abstract: A sensing circuit and method is disclosed, which may comprise a plurality of transmitting or receiving elements each defining a pixel location defined by a gap between the respective one of the plurality of transmitting or receiving elements and a single element of the opposing type to the respective transmitting or receiving element, and a controller configured to provide or receive a probing signal to or from a group of at least two of the plurality of transmitting or receiving elements, at the same time, thereby increasing the effective area providing the transmitting of or the receiving of the probing signal for each pixel location imaged. The group of transmitting or receiving elements may form a symmetric pattern, which may be centered on the pixel location. The plurality of transmitting or receiving elements may form at least one linear pixel array with the respective single receiving or transmitting element.

Abstract: An apparatus and method for detecting the presence of a finger on a fingerprint sensor is disclosed in one embodiment of the invention as including transmitting a probing signal, comprising a series of probing pulses, to a fingerprint sensing area. A response signal, comprising a series of response pulses, is received from the fingerprint sensing area in response to the probing signal. An upper reference signal is generated and finger activity is detected on the fingerprint sensing area by monitoring whether the peaks of the response pulses exceed the reference signal.

Abstract: An apparatus and method for detecting the presence of a finger on a fingerprint sensor is disclosed in one embodiment of the invention as including transmitting a probing signal, comprising a series of probing pulses, to a fingerprint sensing area. A response signal, comprising a series of response pulses, is received from the fingerprint sensing area in response to the probing signal. An upper reference signal is generated and finger activity is detected on the fingerprint sensing area by monitoring whether the peaks of the response pulses exceed the reference signal.

Abstract: An apparatus for reducing noise in fingerprint sensing circuits is disclosed in one embodiment of the invention as including a fingerprint sensing area onto which a user can apply a fingerprint. An analog front end is coupled to the fingerprint sensing area and is configured to generate an analog response signal. An analog-to-digital converter (ADC) samples the analog response signal and converts the sample to a digital value, which may be received by a digital device such as a processor or CPU. To reduce the amount of the noise that is present in the analog response signal and therefore reflected in the digital value, the digital device may be shut down while the ADC is sampling the analog response signal.

Abstract: An apparatus for reducing noise in fingerprint sensing circuits is disclosed in one embodiment of the invention as including a fingerprint sensing area onto which a user can apply a fingerprint. An analog front end is coupled to the fingerprint sensing area and is configured to generate an analog response signal. An analog-to-digital converter (ADC) samples the analog response signal and converts the sample to a digital value, which may be received by a digital device such as a processor or CPU. To reduce the amount of the noise that is present in the analog response signal and therefore reflected in the digital value, the digital device may be shut down while the ADC is sampling the analog response signal.

Abstract: An apparatus is disclosed in a first embodiment of the invention as including a non-conductive substrate providing a first surface onto which a user can apply a fingerprint. A fingerprint sensing circuit is applied to a second surface of the non-conductive substrate opposite the first surface. The fingerprint sensing circuit is capable of sensing a fingerprint through the non-conductive substrate. A navigation device is positioned adjacent to (e.g., below) the non-conductive substrate and is capable of being manipulated by the user through the non-conductive substrate.

Abstract: A fingerprint sensing circuit for reducing noise and parasitic capacitive coupling is disclosed in one embodiment of the invention as including a plurality of transmitting elements to sequentially emit a probing signal. A digital ground is provided to ground digital components in the fingerprint sensing circuit. A quiet ground, separate from and quieter than the digital ground, is provided to ground transmitting elements that are not transmitting the probing signal. Similarly, control logic is provided to connect, to the quiet ground, transmitting elements that are not transmitting the probing signal, while disconnecting, from the quiet ground, transmitting elements that are emitting the probing signal. The quiet ground helps to reduce the adverse effects of parasitic capacitive coupling and noise on the inactive transmitting elements.

Abstract: A fingerprint sensor with programmable sensing patterns is disclosed in one embodiment of the invention as including a fingerprint sensing circuit having multiple I/O interconnects. The I/O interconnects are configured to sequentially drive a plurality of fingerprint sensing elements. A memory device may be operably coupled to the fingerprint sensing circuit. A programmable data structure, such as a table, file, character string, numeric value, array, or the like may be stored in the memory device to designate a pattern for driving the fingerprint sensing elements. The fingerprint sensing circuit is configured to drive the fingerprint sensing elements according to the designated pattern. In selected embodiments, the fingerprint sensing elements may include transmitting elements, receiving elements, or a combination thereof.

Abstract: An apparatus and method for detecting the presence of a finger on a fingerprint sensor is disclosed in one embodiment of the invention as including transmitting a probing signal, comprising a series of probing pulses, to a fingerprint sensing area. A response signal, comprising a series of response pulses, is received from the fingerprint sensing area in response to the probing signal. An upper reference signal is generated and finger activity is detected on the fingerprint sensing area by monitoring whether the peaks of the response pulses exceed the reference signal.

Abstract: An apparatus for culling substantially redundant data in a fingerprint sensing circuit is disclosed in one embodiment of the invention as including an input module, a storage module, a comparator module, and a determination module. The input module may receive sets of data samples from an array of fingerprint sensing elements. The sets of data samples may be stored by the storage module. The comparator module may calculate a difference between each data sample from a first-received set, and a corresponding data sample from a second-received set. The determination module may count the number of difference values that exceed a predetermined difference limit, and identify the second set of data samples as redundant if the number of difference values counted is less than a pre-set count limit.

Abstract: An apparatus for reducing power consumption in fingerprint-sensing circuits is disclosed in one embodiment of the invention as including a fingerprint sensing area onto which a user can apply a fingerprint. An integrated circuit communicates with the fingerprint sensing area and is configured to detect finger activity over the fingerprint sensing area. The integrated circuit includes a primary logic portion configured to assume control of the integrated circuit when finger activity is detected over the fingerprint sensing area. The integrated circuit also includes a secondary logic portion configured to assume control of the integrated circuit and shut off power to the primary logic portion when finger activity is not detected over the fingerprint sensing area.

Abstract: A low power oscillator is disclosed in one embodiment of the invention as including a Schmitt trigger having an input, an output, and an input stage coupled to the input. The input stage may include multiple transistors connected in series between a power source and ground. A switch, controlled by the output of the Schmitt trigger, may be connected in series with the multiple transistors. The switch is configured to interrupt shoot-through current passing through the transistors when the transistors are turned on at the same time. In certain embodiments, the switch may reduce the shoot-through current by substantially half.

Abstract: A fingerprint sensor with programmable sensing patterns is disclosed in one embodiment of the invention as including a fingerprint sensing circuit having multiple I/O interconnects. The I/O interconnects are configured to sequentially drive a plurality of fingerprint sensing elements. A memory device may be operably coupled to the fingerprint sensing circuit. A programmable data structure, such as a table, file, character string, numeric value, array, or the like may be stored in the memory device to designate a pattern for driving the fingerprint sensing elements. The fingerprint sensing circuit is configured to drive the fingerprint sensing elements according to the designated pattern. In selected embodiments, the fingerprint sensing elements may include transmitting elements, receiving elements, or a combination thereof.

Abstract: An apparatus for reducing noise in fingerprint sensing circuits is disclosed in one embodiment of the invention as including a fingerprint sensing area onto which a user can apply a fingerprint. An analog front end is coupled to the fingerprint sensing area and is configured to generate an analog response signal. An analog-to-digital converter (ADC) samples the analog response signal and converts the sample to a digital value, which may be received by a digital device such as a processor or CPU. To reduce the amount of the noise that is present in the analog response signal and therefore reflected in the digital value, the digital device may be shut down while the ADC is sampling the analog response signal.

Abstract: A fingerprint sensing circuit for reducing noise and parasitic capacitive coupling is disclosed in one embodiment of the invention as including a plurality of transmitting elements to sequentially emit a probing signal. A digital ground is provided to ground digital components in the fingerprint sensing circuit. A quiet ground, separate from and quieter than the digital ground, is provided to ground transmitting elements that are not transmitting the probing signal. Similarly, control logic is provided to connect, to the quiet ground, transmitting elements that are not transmitting the probing signal, while disconnecting, from the quiet ground, transmitting elements that are emitting the probing signal. The quiet ground helps to reduce the adverse effects of parasitic capacitive coupling and noise on the inactive transmitting elements.

Abstract: A method and apparatus for dynamically assigning and enabling a unique functional address for a Universal Serial Bus device. A host assigns the unique functional address during a control transaction. The Universal Serial Bus device disables the default address and enables the unique functional address during a status stage of the control transaction to avoid an error window.