US 2009/0021283 A1Published application

High speed latched comparator

AssigneeTexas Instruments Incorporated

InventorsRobert F. Payne, Marco Corsi

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Abstract

An improved latched comparator, including a track mode circuit, a latch and a latch and track select circuit. The track mode circuit includes two transistors having their sources connected together, and their respective gates receiving a respective first and second input, and their drains connected to the power supply by respective resistors. The latch includes a further two transistors having their sources connected together, a gate of each connected to a drain of the other, and their drains connected to a respective one of the common connection node of the first transistor and the first resistor, and the second transistor and the second resistor. The latch and track select circuit includes a further transistor having an source connected to a current sink connected to ground, having a gate connected to receive a track signal and having a drain connected to the common connection node of the first and second transistors, and a still further transistor having a source connected to the current sink connected to ground, having a gate connected to receive a latch signal and having a drain connected to the common connection node of the third and fourth transistors. Bipolar embodiments are also included.

Claims3

Dependent claims

A latched comparator, comprising:

a pre-amplifier, comprising
a first bipolar transistor and a second bipolar transistor having their emitters connected together, a base of the first bipolar transistor connected to receive a first input, a base of the second bipolar transistor connected to receive a second input,
a first resistor connected between a collector of the first bipolar transistor and a supply port of a power supply,
a second resistor connected between a collector of the second bipolar transistor and the supply port of the power supply, and
a first current sink connected between the common connection node of the first and second bipolar transistor and the power supply ground;
a latch, comprising
a third bipolar transistor and a fourth bipolar transistor having their emitters connected together, a base of each connected to a collector of the other,
a third resistor connected between a collector of the third bipolar transistor and the common connection node of the first transistor and the first resistor, and
a fourth resistor connected between a collector of the fourth bipolar transistor and the common connection node of the second transistor and the second resistor;
and
a latch and track select circuit, comprising
a fifth bipolar transistor having an emitter connected to a second current sink connected to ground, having a base connected to receive a latch signal and having a collector connected to the common connection node of the third and fourth transistors, and
a sixth bipolar transistor having an emitter connected to the second current sink connected to ground, having a base connected to receive a track signal and having a collector connected to the supply port of the power supply.

10 more elements

Dependencies are inferred from the claim text.