Low power high bandwidth high speed comparator
AssigneeAnalog Devices, Inc.
InventorsParitosh Bhoraskar, Ahmed Mohamed Abdelatty Ali, Christopher Daniel Dillon
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Abstract
Comparators are implemented in many circuits, including analog-to-digital converters (ADCs). Some ADCs demand high bandwidth, low power consumption, and high speed. To address these requirements, a comparator circuit can be implemented without a separate pre-amplifier, where a sampling network drives a latch directly. Specifically, the comparator circuit integrates a pre-amplifier within the latch in a manner that ensures low power and high speed operation.
Claims20
A low power and high bandwidth comparator, comprising:
- a sampling network to derive a difference between an input signal and a reference;
- a latch comprising a first cross-coupled pair of transistors and output nodes at respective first terminals of the first cross-coupled pair of transistors, wherein gates of the first cross-coupled pair of transistors are cross-coupled to the output nodes;
- and
- first and second transistors to couple the difference from the sampling network to the gates of the first cross-coupled pair of transistors respectively.
A low power and high bandwidth comparator, comprising:
- a switched capacitor network to sample an input signal and derive a difference between the input signal and a reference;
- and
- a latch having an integrated pre-amplifier, latching circuitry, and output nodes, wherein the integrated pre-amplifier and the latching circuitry share the output nodes, and the difference drives the integrated pre-amplifier during an acquire phase of the latch;
- wherein the integrated pre-amplifier comprises a first cross-coupled pair of transistors, and the first cross-coupled pair of transistors have gates which are cross-coupled to the output nodes via respective level-shifting capacitors.
A method for performing a latched comparison, comprising:
- comparing an input signal against a reference to generate a difference;
- acquiring and amplifying the difference driving gates of a first cross-coupled pair of transistors using the difference, and setting a current through the first cross-coupled pair of transistors using a tail current transistor connected to sources of the first cross-coupled pair of transistors;
- and
- latching the difference by the first cross-coupled pair of transistors and second cross-coupled pair of transistors.
Dependencies are inferred from the claim text.