Abstract:
An output stage of a buffer or an amplifier connected to a switched capacitive load can operate in two phases to perform precharging and fine settling. The precharging and fine settling phases can be synchronized to the switching phases of the switched capacitive load connected to the amplifier. During the precharging phase, the output stage can be disconnected from the prior stages of the amplifier, and the output node of the amplifier can be connected to the switched capacitive load to precharge the capacitive load with the voltage already stored in the output stage. During the fine settling phase, the output stage can be reconnected to the prior stages of the amplifier, and the amplifier nodes can settle and get ready for sampling, which can occur at the end of the fine settling phase.
Abstract:
A common mode reference circuit comprises a divider stage and an output stage. The divider stage includes a first n-channel field effect transistor and p-channel filed effect transistor (NFET/PFET) pair connected in series to a high supply voltage circuit node; and a second NFET/PFET pair connected in series to a low supply voltage circuit node. The output stage includes a first FET connected as a current mirror to a transistor of the first NFET/PFET pair; a second FET connected as a current mirror to a transistor of the second NFET/PFET pair; and a common mode reference output at a series connection from the first FET to the second FET.
Abstract:
A capacitive gain amplifier circuit includes two sets of Miller capacitors and two output stage differential amplifier circuits. A first set of Miller capacitors is used to compensate the first output stage differential amplifier circuit during a first phase that resets the first output stage differential amplifier circuit. The second set of Miller capacitors is used to compensate the first output stage differential amplifier circuit during a second phase that chops a signal being amplified. The second set of Miller capacitors is swapped from one polarity to an opposite polarity of the first output stage differential amplifier circuit during successive second phases. The second output stage differential amplifier circuit includes a set of inputs selectively coupled with the inputs of the first output stage differential amplifier circuit and a set of outputs selectively coupled with the outputs of the first output stage differential amplifier circuit during the second phase.
Abstract:
The amplifier circuit includes a pair of differential input stages coupled to an output stage where both a selected input stage and an unselected input stage are active with one of either a differential input signal or a reference voltage. A switching network couples a first input differential signal to a first differential input stage and a reference voltage to a second differential input stage when an amplifier input signal is less than a threshold voltage. The switching circuit also couples the second input differential signal to the second differential input stage and the reference voltage to the first differential input stage when the amplifier input signal is greater than the threshold signal.
Abstract:
An output stage of a buffer or an amplifier connected to a switched capacitive load can operate in two phases to perform precharging and fine settling. The precharging and fine settling phases can be synchronized to the switching phases of the switched capacitive load connected to the amplifier. During the precharging phase, the output stage can be disconnected from the prior stages of the amplifier, and the output node of the amplifier can be connected to the switched capacitive load to precharge the capacitive load with the voltage already stored in the output stage. During the fine settling phase, the output stage can be reconnected to the prior stages of the amplifier, and the amplifier nodes can settle and get ready for sampling, which can occur at the end of the fine settling phase.
Abstract:
A capacitive gain amplifier circuit amplifies an input signal by a pair of differential amplifier circuits couples in series. The first differential amplifier circuit is reset during an autozero phase while disconnected from the second differential amplifier circuit, and the first and second differential amplifier circuits are connected together in series during a chop phase. A set of feedback capacitors is selectively switched in between respective outputs of the second differential amplifier circuit and respective inputs of the first differential amplifier circuit during the chop phase.
Abstract:
The amplifier circuit includes a pair of differential input stages coupled to an output stage where both a selected input stage and an unselected input stage are active with one of either a differential input signal or a reference voltage. A switching network couples a first input differential signal to a first differential input stage and a reference voltage to a second differential input stage when an amplifier input signal is less than a threshold voltage. The switching circuit also couples the second input differential signal to the second differential input stage and the reference voltage to the first differential input stage when the amplifier input signal is greater than the threshold signal.
Abstract:
A capacitive gain amplifier circuit amplifies an input signal by a pair of differential amplifier circuits couples in series. The first differential amplifier circuit is reset during an autozero phase while disconnected from the second differential amplifier circuit, and the first and second differential amplifier circuits are connected together in series during a chop phase. A set of feedback capacitors is selectively switched in between respective outputs of the second differential amplifier circuit and respective inputs of the first differential amplifier circuit during the chop phase.
Abstract:
An input stage to an analog to digital converter (ADC) includes at least one sampling capacitor (SC) for sampling an input signal in acquire phases, a capacitive gain amplifier (CGA) for providing the input signal to the SC, and bandwidth control means. The bandwidth control means is configured to ensure that the SC has a first bandwidth during a first part of an acquire phase and has a second bandwidth during a subsequent, second, part of said acquire phase, the second bandwidth being smaller than the first. In this manner, first, the input signal is sampled at a higher, first, bandwidth allowing to take advantage of using a high-bandwidth CGA to minimize settling error on the SC, and, next, during a second part of the same acquire phase, the input signal is sampled at a lower, second, bandwidth advantageously decreasing noise resulting from the use of a high-bandwidth CGA.
Abstract:
A capacitive gain amplifier circuit includes two sets of Miller capacitors and two output stage differential amplifier circuits. A first set of Miller capacitors is used to compensate the first output stage differential amplifier circuit during a first phase that resets the first output stage differential amplifier circuit. The second set of Miller capacitors is used to compensate the first output stage differential amplifier circuit during a second phase that chops a signal being amplified. The second set of Miller capacitors is swapped from one polarity to an opposite polarity of the first output stage differential amplifier circuit during successive second phases. The second output stage differential amplifier circuit includes a set of inputs selectively coupled with the inputs of the first output stage differential amplifier circuit and a set of outputs selectively coupled with the outputs of the first output stage differential amplifier circuit during the second phase.