Comparator circuit
AssigneeDiscovision Associates
InventorAnthony M. Jones
Life of this patent
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Abstract
A high speed analog-to-digital converter employs a comparator having first and second units cross coupled in a positive feedback loop. The units are alternately connected to an input voltage and a reference voltage, after which positive feedback is introduced established, and a differential output established. The arrangement is fully symmetric, and balanced and rejects common-mode switching noise.
Claims13
An analog-to-digital converter apparatus, comprising a comparator having first and second units, each of said units comprising:
- a capacitor connected to a first node and a second node;
- a first switch means for connecting said first node to a selected one of an input voltage and a reference voltage;
- an inverter having an input connected to said second node, and an output;
- and
- a second switch means for connecting said output of said inverter to said second node of an other of said units.
A comparator having first and second units, each of said units comprising:
- a capacitor connected to a first node and a second node;
- a first switch means for connecting said first node to a selected one of an input voltage and a reference voltage;
- an inverter having an input connected to said second node, and an output;
- and
- a second switch means for connecting said output of said inverter to said second node of an other of said units.
A method of comparing two voltages, comprising in each of two associated units the steps of:
- connecting a capacitor to a first node and a second node;
- connecting an input of an inverter to said second node;
- in a first phase of operation:
- connecting said first node to a selected one of an input voltage and a reference voltage;
- in a second phase of operation:
- disconnecting said first node from said selected one of said input voltage and said reference voltage;
- and
- connecting said first node to another of said input voltage and said reference voltage;
- and
- in a third phase of operation:
- disconnecting said first node from said other of said input voltage and said reference voltage;
- and
- connecting said output of said inverter to said second node of an other of said associated units.
Dependencies are inferred from the claim text.