Abstract: An improved slicer for a data receiver is described. In particular, an improved slicer architecture with improved noise immunity and improved tolerance to signal level shift of an input signal to the data receiver is disclosed. The improvement is achieved through using multiple comparators to account for a wider range of the noise and input signal level shift. Other methods and apparatuses are described therein, including a two-comparator and a four comparator embodiments.

Abstract: An apparatus, method, and system for DC offset cancellation are provided herein. For instance, the apparatus can include a first commutating mixer switch and a second commutating mixer switch. The first commutating mixer switch can have a first input port configured to receive a first differential signal and a first differential output port. The second commutating mixer switch can have a second input port configured to receive a second differential offset signal and a second differential output port. The first and second differential output ports can be coupled to one another to provide a combined differential output signal.

Abstract: An apparatus, method, and system for DC offset cancellation are provided herein. For instance, the apparatus can include a first commutating mixer switch and a second commutating mixer switch. The first commutating mixer switch can have a first input port configured to receive a first differential signal and a first differential output port. The second commutating mixer switch can have a second input port configured to receive a second differential offset signal and a second differential output port. The first and second differential output ports can be coupled to one another to provide a combined differential output signal.

Abstract: A mixer for a radio transceiver includes a commutating mixer switch having a first differential input port coupled to a DC offset cancellation path. The first differential input port of the mixer switch includes a first terminal coupled to a first end of a first resistor and a second terminal coupled to a first end of a second resistor. Second ends of the first and second resistors are configured to receive a differential input signal. The DC offset cancellation path may provide a resistively coupled DC calibration signal for reducing the magnitude of DC offsets that may be present at the input of the mixer switch. The concept can be used for either image or non-image reject mixers.

Abstract: A mixer for a radio transceiver includes a commutating mixer switch having a first differential input port coupled to a DC offset cancellation path. The first differential input port of the mixer switch includes a first terminal coupled to a first end of a first resistor and a second terminal coupled to a first end of a second resistor. Second ends of the first and second resistors are configured to receive a differential input signal. The DC offset cancellation path may provide a resistively coupled DC calibration signal for reducing the magnitude of DC offsets that may be present at the input of the mixer switch. The concept can be used for either image or non-image reject mixers.

Abstract: A mixer for a radio transceiver includes a commutating mixer switch having a first differential input port coupled to a DC offset cancellation path. The first differential input port of the mixer switch includes a first terminal coupled to a first end of a first resistor and a second terminal coupled to a first end of a second resistor. Second ends of the first and second resistors are configured to receive a differential input signal. The DC offset cancellation path may provide a resistively coupled DC calibration signal for reducing the magnitude of DC offsets that may be present at the input of the mixer switch. The concept can be used for either image or non-image reject mixers.

Abstract: Effectively defect free images are obtained from CMOS image sensors through a two step method in which the addresses of bad pixels are recorded during sensor testing and stored in an on-chip directory. Then, during sensor readout, each pixel address is checked to determine if it represents that of a bad pixel. If this is determined to be the case, the bad pixel value is replaced by another value. This replacement value is generated from an average of the nearest-neighbors that are not defective. If testing is performed at the wafer level, said bad pixel and nearest neighbor data may be used to modify the final level wiring so that bad pixels are disconnected and replaced by their nearest neighbors.

Abstract: The invention provides a method and apparatus for reducing image lag in CMOS active pixel sensors at low light levels by controlling the reset level. By ensuring that the reset level is independent of the preceding signal level, the problem of image lag can be avoided. Always resetting a photodiode to a fixed voltage is a hard reset. The maximum signal swing is limited by the reset level and the column readout amplifier. If the column circuits are not modified, using hard reset can reduce the maximum signal swing. However in dark images only a portion of the full scale is used. Therefore the amplifier gain setting can be used to determine whether to use a hard reset or soft reset. This method and apparatus for using hard or soft reset dependent on signal level improves image quality at low light levels without compromising performance at high illumination.

Abstract: Effectively defect free images are obtained from CMOS image sensors through a two step method in which the addresses of bad pixels are recorded during sensor testing and stored in an on-chip directory. Then, during sensor readout, each pixel address is checked to determine if it represents that of a bad pixel. If this is determined to be the case, the bad pixel value is replaced by another value. This replacement value is generated from an average of the nearest-neighbors that are not defective. If testing is performed at the wafer level, said bad pixel and nearest neighbor data may be used to modify the final level wiring so that bad pixels are disconnected and replaced by their nearest neighbors.

Abstract: Apparatus and methods for testing an active pixel sensor ensure that a signal proportional to the quantity of light energy impinging on the active pixel sensor is reliably and accurately captured and made available for further on processing the rest of the APS system circuitry. The apparatus and method determines the capacitance of a photo-conversion device of the active pixel sensor. The apparatus and method determines that an active pixel sensor is functioning correctly. The apparatus and method determines the performance of an active pixel sensor. Where the performance of the active pixel sensor is a measure of linearity of the active pixel sensor and a connected chain of circuitry that process the signal converted by the photo-conversion device of the active pixel sensor.

Abstract: A circuit of bias-current source has a band-gape designed circuit associating with a V-I converter. The band-gap circuit has a first output node A. From the first node A to a ground, a first resistor, a second resistor and a diode are connected in cascade. A second output node B is referred to the junction between the first and the second resistors. The first node A and second node B supply a first voltage source and a second voltage source, respectively. The second voltage is voltage source and the first voltage source is converted into a current source by a V-I converter that has an operational amplifier (op-amp), a third resistor, a first transistor, and a second transistor. A Negative input end of the op-amp receives the first voltage, and a positive input end of the op-amp receives a feedback. An output from the operational amplifier is coupled to gate of the first transistor. A source of the first transistor is applied with a system voltage.

Abstract: A mixer for a radio transceiver includes a commutating mixer switch having a first differential input port coupled to a DC offset cancellation path. The first differential input port of the mixer switch includes a first terminal coupled to a first end of a first resistor and a second terminal coupled to a first end of a second resistor. Second ends of the first and second resistors are configured to receive a differential input signal. The DC offset cancellation path may provide a resistively coupled DC calibration signal for reducing the magnitude of DC offsets that may be present at the input of the mixer switch. The concept can be used for either image or non-image reject mixers.

Abstract: A duty cycle correcting circuit is described having a first capacitor connected between a first node and a reference node and a second capacitor connected between a second node and the reference node. When the duty cycle of the output clock signal is greater than 50% the voltage across the second capacitor decreases thereby increasing the charging rate of the first capacitor, decreasing the discharging rate of the first capacitor, and restoring the output duty cycle to 50%. When the duty cycle of the output clock signal is less than 50% the voltage across the second capacitor increases thereby decreasing the charging rate of the first capacitor, increasing the discharging rate of the first capacitor, any restoring output duty cycle to 50%.

Abstract: The invention provides a method and apparatus for reducing image lag in CMOS active pixel sensors at low light levels by controlling the reset level. By ensuring that the reset level is independent of the preceding signal level, the problem of image lag can be avoided. Always resetting a photodiode to a fixed voltage is a hard reset. The maximum signal swing is limited by the reset level and the column readout amplifier. If the column circuits are not modified, using hard reset can reduce the maximum signal swing. However in dark images only a portion of the full scale is used. Therefore the amplifier gain setting can be used to determine whether to use a hard reset or soft reset. This method and apparatus for using hard or soft reset dependent on signal level improves image quality at low light levels without compromising performance at high illumination.

Abstract: The invention provides a simple fuse structure that has been implemented using the existing standard CMOS process layers without adding to the process complexity. The fuse is applied as an integrated on-chip memory element in the CMOS image sensor circuit to record the address information of the bad pixels. The application of integrated memory element on the same chip eliminates the need for external memory and therefore reduces the cost and overall component count of the camera module. The dynamic readout circuit of the fuse array reduces the data delay and increases the operating frequency of the circuit. In a process that has multiple layers of passivation, there can be a thin layer of passivation layer on top of the fuse to prevent oxidation and moisture penetration.

Abstract: Then circuit includes an analog-to-digital converter (ADC); and one or more switched capacitor amplifier stages connected together in series with a first switched capacitor amplifier stage for receiving the analog input signal, and a last switched capacitor amplifier stage connected to the ADC. Moreover, each of the plurality of switched capacitor amplifier stages preferably has a selectable gain to permit control of an overall gain of the analog input signal upstream of the ADC. In addition, the first stage may also serve as a sample and hold circuit for the ADC. In one embodiment, the circuit may comprise an integrated circuit substrate on which the ADC and the plurality of switched capacitor amplifiers are formed so that the analog-to-digital converter is a monolithic integrated circuit. The circuit may also control the gain of each of the plurality of switched capacitor amplifier stages based upon a digital gain control word.

Abstract: The calibration method preferably comprises the steps of: driving the analog-to-digital converter (ADC) with at least one test signal; calibrating the driven ADC over a series of successive ADC calibrations; generating a series of successive ADC figure of merit measurements for respective successive ADC calibrations, the series of successive ADC figure of merit measurements defining at least a portion of a curve having a local minimum/maximum; and stopping calibrating at an ADC calibration corresponding to the local minimum/maximum of the curve defined by the series of successive ADC figure of merit measurements. The step of calibrating preferably comprises incrementally calibrating the ADC over the series of successive ADC calibrations. The method preferably further comprises the step of determining the local minimum/maximum of the curve.

Abstract: An analog-to-digital converter (ADC) integrated circuit includes a subconverter stage having an amplifier with a non-ideal gain, and a reference voltage generator for generating a reference voltage for the subconverter stage. The reference voltage generator is adjustable and may include trimmable resistors for providing an adjusted or trimmed reference voltage to a second subconverter stage or second operation of the subconverter stage to compensate for a non-ideal gain of the amplifier. Complicated and difficult capacitor trimming for the amplifier is not needed; rather, a relatively simple and predictable trimming of thin film resistors in the reference voltage generator may be used to compensate for the non-ideal gain of the amplifier and improve performance. A method and apparatus for calibrating the ADC are also disclosed.

Abstract: A BIMOS driver circuit and method in which a push-pull pair of PNP-NPN bipolar transistors replaces the middle CMOS inverter stages in a circuit for driving a capacitive load. The rise and fall times of the circuit are made symmetrical by feeding back driver circuit output to operate a feedback transistor which removes the base charge stored in a PNP transistor of the bipolar push-pull pair, and maintains low propagation delay.