Abstract:
A stage, suitable for use in and analog to digital converter or a digital to analog converter, comprises a plurality of slices. The slices can be operated together to form a composite output having reduced thermal noise, while each slice on its own has sufficiently small capacitance to respond quickly to changes in digital codes applied to the slice. This allows a fast conversion to be achieved without loss of noise performance. The slices can be sub-divided to reduce scaling mismatch between the most significant bit and the least significant bit. A shuffling scheme is implemented that allows shuffling to occur between the sub-sections of the slices without needing to implement a massively complex shuffler.
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:
An amplifier input stage comprising first and second p-type transistors, wherein sources of the first and second p-type transistors are connected to a first node, a drain of the first p-type transistor is connected to a first output of the amplifier input stage, a drain of the second p-type transistor is connected to a second output of the amplifier input stage, a gate of the first p-type transistor is configured to receive a first signal of an input stage differential input signal and a gate of the second p-type transistor is configured to receive a second signal of the input stage differential input signal; first and second n-type transistors, wherein sources of the first and second n-type transistors are connected to a second node, a drain of the first n-type transistor is connected to a third output of the amplifier input stage, a drain of the second n-type transistor is connected to a fourth output of the amplifier input stage, a gate of the first n-type transistor is configured to receive the first signal of the input stage differential input signal and a gate of the second n-type transistor is configured to receive the second signal of the input stage differential input signal; a first circuit arranged to provide a first portion of a first bias current to the first node; and a second circuit arranged to draw a second portion of the first bias current from the second node; wherein the first and second portions are determined by a first signal of an amplifier input signal.
Abstract:
An amplifier input stage comprising first and second p-type transistors, wherein sources of the first and second p-type transistors are connected to a first node, a drain of the first p-type transistor is connected to a first output of the amplifier input stage, a drain of the second p-type transistor is connected to a second output of the amplifier input stage, a gate of the first p-type transistor is configured to receive a first signal of an input stage differential input signal and a gate of the second p-type transistor is configured to receive a second signal of the input stage differential input signal; first and second n-type transistors, wherein sources of the first and second n-type transistors are connected to a second node, a drain of the first n-type transistor is connected to a third output of the amplifier input stage, a drain of the second n-type transistor is connected to a fourth output of the amplifier input stage, a gate of the first n-type transistor is configured to receive the first signal of the input stage differential input signal and a gate of the second n-type transistor is configured to receive the second signal of the input stage differential input signal; a first circuit arranged to provide a first portion of a first bias current to the first node; and a second circuit arranged to draw a second portion of the first bias current from the second node; wherein the first and second portions are determined by a first signal of an amplifier input signal.
Abstract:
Apparatus and methods for autozero amplifiers are provided herein. In certain configurations, an autozero amplifier includes at least three transconductance stages and an autozero timing control circuit configured to control an autozero sequence of the transconductance stages. The autozero timing control circuit can stagger autozeroing of the transconductance stages, such that a relatively small amount of the amplifier's amplification circuitry is connected to or disconnected from the amplifier's signal path at any given time. For example, in certain configurations, when one of the transconductance stages in autozeroed over a particular time interval, the remaining transconductance stages can operate in parallel to provide amplification during that time interval.
Abstract:
Apparatus and methods for autozero amplifiers are provided herein. In certain configurations, an autozero amplifier includes at least three transconductance stages and an autozero timing control circuit configured to control an autozero sequence of the transconductance stages. The autozero timing control circuit can stagger autozeroing of the transconductance stages, such that a relatively small amount of the amplifier's amplification circuitry is connected to or disconnected from the amplifier's signal path at any given time. For example, in certain configurations, when one of the transconductance stages in autozeroed over a particular time interval, the remaining transconductance stages can operate in parallel to provide amplification during that time interval.