An auto calibration method used in switching converters with constant on-time control. The auto calibration method includes: generating a periodical clock signal with a predetermined duty cycle; providing a first voltage and a second voltage to an on-time control circuit to generate an on-time control signal based on the first and second voltage; providing the clock signal and on-time control signal to a logic circuit to generate a switch control signal based on the clock signal and on-time control signal; comparing the duty cycle of the switch control signal with the duty cycle of the clock signal to adjust a calibration code signal; and adjusting circuit parameters of the on-time control circuit in accordance with the calibration code signal.

An auto calibration method used in switching converters with constant on-time control. The auto calibration method includes: generating a periodical clock signal with a predetermined duty cycle; providing a first voltage and a second voltage to an on-time control circuit to generate an on-time control signal based on the first and second voltage; providing the clock signal and on-time control signal to a logic circuit to generate a switch control signal based on the clock signal and on-time control signal; comparing the duty cycle of the switch control signal with the duty cycle of the clock signal to adjust a calibration code signal; and adjusting circuit parameters of the on-time control circuit in accordance with the calibration code signal.

A signal processing apparatus comprising: an analog-digital converter that uses reference signals having different slopes from each other; a supply unit that supplies analog signals of predetermined different output levels; and a calculation unit that calculates a slope ratio and an offset amount between the plurality of different slopes for correcting a converted digital signal based on digital signals respectively obtained by converting the analog signals of the different output levels using the reference signals. In a case where the conversion is performed using a reference signal with a steeper slope, the supply unit supplies at least one high level analog signal whose level is higher than a case where the conversion is performed using a reference signal with a gentler slope, and a digital signal obtained by converting the high level analog signal is further used when calculating the slope ratio.

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.

A charge rebalancing integration circuit can help keep an output node of a front-end integration circuit within a specified range, e.g., without requiring resetting of the integration capacitor. The process of monitoring and rebalancing the integration circuit can operate on a much shorter time base than the integration time period, which can allow for multiple charge balancing charge transfer events during the integration time period, and sampling of the integration capacitor once per integration time period, such as at the end of that integration time period. Information about the charge rebalancing can be used to adjust subsequent discrete-time signal processing, such as digitized values of the samples. Improved dynamic range and noise performance is possible. Computed tomography (CT) imaging and other use cases are described, including those with variable integration periods.

A signal processing apparatus comprising: an analog-digital converter that uses reference signals having different slopes from each other; a supply unit that supplies analog signals of predetermined different output levels; and a calculation unit that calculates a slope ratio and an offset amount between the plurality of different slopes for correcting a converted digital signal based on digital signals respectively obtained by converting the analog signals of the different output levels using the reference signals. In a case where the conversion is performed using a reference signal with a steeper slope, the supply unit supplies at least one high level analog signal whose level is higher than a case where the conversion is performed using a reference signal with a gentler slope, and a digital signal obtained by converting the high level analog signal is further used when calculating the slope ratio.

A sensor that is capable of detecting a pulse of a user by using a proximity illumination sensor or a proximity sensor is provided. A proximity sensor (14) that includes a pulse detection function includes a count adjustment circuit (5) that performs adjustment such that a digital output value (ADCOUT1) from an analog-digital conversion circuit (4) changes in accordance with each value of a distance at least in a prescribed range of the distance between a photodiode (2) and a detected object (a finger in the drawing) and a digital filter (6) for detecting a cycle of the digital output value (ADCOUT1) from the analog-digital conversion circuit (4).

An integrator according to an embodiment includes first and second nodes, first to fifth switches, first and second main integration capacitors, and a first subsidiary integration capacitor. The first (second, third, fourth, fifth) switch has one end connected to a first (third, first, fourth, first) node and the other end connected to a third (second, fourth, second, fifth) node. The first main integration capacitor has one end connected to the third node and the other end connected to a standard voltage line. The second main integration capacitor has one end connected to the fourth node and the other end connected to the standard voltage line. The first subsidiary integration capacitor that has one end connected to the fifth node and the other end connected to the standard voltage line.

An integrator according to an embodiment includes first and second nodes, first to fifth switches, first and second main integration capacitors, and a first subsidiary integration capacitor. The first (second, third, fourth, fifth) switch has one end connected to a first (third, first, fourth, first) node and the other end connected to a third (second, fourth, second, fifth) node. The first main integration capacitor has one end connected to the third node and the other end connected to a standard voltage line. The second main integration capacitor has one end connected to the fourth node and the other end connected to the standard voltage line. The first subsidiary integration capacitor that has one end connected to the fifth node and the other end connected to the standard voltage line.

A voltage-to-delay converter includes a first reset transistor having a first terminal coupled to a power supply terminal, a gate terminal receiving a reset signal, and a second terminal coupled to a top plate of a first integrating capacitor, and a second reset transistor having a first terminal coupled to a power supply terminal, a gate terminal receiving the reset signal, and a second terminal coupled to a top plate of a second integrating capacitor. First and second input transistors receive first and second input voltages, and are coupled between the top plate of the first and second integrating capacitors, respectively, and a first current source. A discharge current source is coupled to bottom plates of the first and second integrating capacitors. A pulse generator has first and second inputs coupled to the top plate of the first and second integrating capacitors, respectively.