A fingerprint signal processing system for a fingerprint sensor includes a calibration control circuit, a register circuit, a decode circuit and a normalization circuit. The calibration control circuit is configured to receive a background calibration control signal and an image signal from the fingerprint sensor, and convert the image signal into a plurality of digital signals according to a plurality of offsets. When the background calibration control signal is at a high level, the calibration control circuit is configured to read a plurality of calibration parameters from the register circuit.

A system and method for performing discrete frequency transform including a pair of single-bit analog to digital converters (ADCs), a phase converter, a memory, a discrete frequency transform converter and summation circuitry. The ADCs convert an analog input signal into N pairs of binary in-phase and quadrature component samples each being one of four values at a corresponding one of four phases. The phase converter determines a phase value for each pair of component samples. The memory stores a set of discrete frequency transform coefficient values based on N. The discrete frequency transform converter uses a phase value and a pair of discrete frequency transform coefficient values retrieved from the memory for a selected frequency bin to determine a discrete frequency component for each pair of phase component samples. The summation circuitry sums the corresponding N frequency domain components for determining a frequency domain value for the selected frequency bin.

An electronic circuit includes first and second channels which respectively receive first and second analog signals. The first channel includes a first digital to analog converter having an output coupled to a first input of a first sign comparator, and the second channel includes a second digital to analog converter. A switch network selectively couples, upon reception of a self-test mode signal signaling a test phase, an output of the second digital to analog converter to a second input of the first sign comparator. A ramp generation circuit supplies to the first digital to analog converter and the second digital to analog converter two identical ramps of digital codes, which are shifted by a programmable offset with respect to one another. A checking circuit issues a test status signal based on the output of the first sign comparator.

A processing device of a displacement detection device includes an AD conversion device, a switching circuit, and an arithmetic processing unit. The AD conversion device has first and second AD conversion units. The switching circuit periodically switches between a first connection mode in which a first differential signal is AD-converted by the first AD conversion unit and a second differential signal is AD-converted by the second AD conversion unit, and a second connection mode in which the first differential signal is AD-converted by the second AD conversion unit and the second differential signal is AD-converted by the first AD conversion unit. The arithmetic processing unit outputs displacement information of a scale based on an addition average value of the first differential signals output from the first and second AD conversion units and an addition average value of the second differential signals output from the first and second AD conversion units.

A system for controlling operation of first and second electric fans is provided. The system includes a microcontroller that determines when first analog multiplexer is malfunctioning or a first channel of the first analog-to-digital converter is malfunctioning based on first values obtained from the first analog-to-digital converter. The first values are associated with at least one of a first speed signal associated with the first electric fan and a first driving voltage for the first electric fan that are received by the first analog multiplexer. The microcontroller modifies a control signal to induce the second electric fan to operate at a higher rotational speed when the first analog multiplexer is malfunctioning or the first channel of the first analog-to-digital converter is malfunctioning.

An analog-to-digital converter may include an integrator, a gated ring oscillator, a coarse counter, a phase state register, a counter register, and logic circuitry. The gated ring oscillator may output a phase state signal continuously to the phase state register. The phase state signal includes multiple phase nodes, each of which is created by transmitting a signal through a number of delay stages. One of the phase nodes may be provided to the coarse counter. The phase state register and counter register may store the most current corresponding phase state and coarse counter outputs, respectively. A control signal corresponding to an analog image input signal may control the output of stored phase states and stored coarse counter outputs to the logic circuitry. The logic circuitry may generate a digital version of the analog image input signal based on the outputs of the phase state and counter registers.

Present invention discloses an ADC and an analog-to-digital conversion method. The ADC includes: a clock generator, including M transmission gates, where the M transmission gates are configured to receive a first clock signal that is periodically sent and separately perform gating control on the first clock signal, so as to generate M second clock signals, M is an integer that is greater than or equal to 2; M ADC channels that are configured in a time interleaving manner, configured to receive one analog signal and separately perform, under the control of the M second clock signals, sampling and analog-to-digital conversion on the analog signal, so as to obtain M digital signals, where each ADC channel is corresponding to one clock signal of the M second clock signals; and an adder, configured to add the M digital signals together in a digital field, so as to obtain a digital output signal.

The disclosure provides an analog to digital converter (ADC). The ADC includes a flash ADC. The flash ADC generates a flash output in response to an input signal, and an error correction block generates a known pattern. A selector block is coupled to the flash ADC and the error correction block, and generates a plurality of selected signals in response to the flash output and the known pattern. A digital to analog converter (DAC) is coupled to the selector block, and generates a coarse analog signal in response to the plurality of selected signals. A residue amplifier is coupled to the DAC, and generates a residual analog signal in response to the coarse analog signal, the input signal and an analog PRBS (pseudo random binary sequence) signal. A residual ADC generates a residual code in response to the residual analog signal.

Sampler circuitry, having: an input node which receives an input voltage signal; a primary current path connected between high and low voltage supply nodes; a secondary current path connected between high and low voltage supply nodes; current mirror circuitry; and load circuitry having sampler switches which sample a current signal, where the input node is defined along the primary current path, the primary current path configured to carry a primary current dependent on the input voltage signal; the current mirror circuitry includes a primary side and a secondary side, the primary side connected along the primary current path and the secondary side connected along the secondary current path so that a secondary current dependent on the primary current is caused to flow along the secondary current path; and the load circuitry is connected along the secondary current path so that the secondary current at least partly forms the current signal.

In at least some examples, an integrated circuit includes an input pin and an analog-to-digital converter (ADC) comprising an input terminal coupled to the input pin and an output terminal. The integrated circuit further includes a logic circuit comprising an input terminal coupled to the output terminal of the ADC, a first output terminal, and a second output terminal. The integrated circuit further includes a resistance circuit. In an example, the resistance circuit includes a resistor coupled between the input pin and a first node, a first switch coupled between the first node and a reference voltage pin, and a second switch coupled between the first node and a ground pin.