Differential hysteresis comparator circuits and methods
AssigneeMarvell International Ltd.
InventorsDavid Gozali, Hong Liang Zhang
Life of this patent
Estimating the term…
Abstract
A comparator circuit for providing hysteresis comprises first and second differentially coupled transistors. The first of the differentially coupled transistors provides drain current to first and second load transistors. The second of the differentially coupled transistors provides drain current to third and fourth load transistors. In one example embodiment, the drain of the first of the differentially coupled transistors also drives the gate of the first and third load transistors, while the drain of the second of the differentially coupled transistors drives the gate of the second and fourth transistors.
Claims20
An apparatus comprising:
- a first circuit configured to compare a first input voltage with a second input voltage, wherein the first circuit outputs a first output voltage at a first output and a second output voltage at a second output based on the comparison of the first input voltage and the second input voltage;
- and
- a second circuit configured to compare a third input voltage with a fourth input voltage, wherein the second circuit outputs a third output voltage at a third output and a fourth output voltage at a fourth output based on the comparison of the third input voltage and the fourth input voltage,
- wherein the first circuit is configured to draw a first portion of current from the second output or draw a second portion of current from the first output to cause the first circuit to exhibit a first hysteresis, and
- wherein the second circuit is configured to draw a third portion of current from the fourth output or draw a fourth portion of current from the third output to cause the second circuit to exhibit a second hysteresis, and
- wherein a total amount of hysteresis in the first hysteresis and second hysteresis is configurable based on a ratio between transistor widths in the first circuit and second circuit.
A method comprising:
- comparing, with a first circuit, a first input voltage with a second input voltage;
- outputting a first output voltage at a first output and a second output voltage at a second output based on the comparison of the first input voltage and the second input voltage;
- comparing, with a second circuit, a third input voltage with a fourth input voltage;
- outputting a third output voltage at a third output and a fourth output voltage at a fourth output based on the comparison of the third input voltage and the fourth input voltage;
- drawing a first portion of current from the second output or drawing a second portion of current from the first output to cause the first circuit to exhibit a first hysteresis;
- and
- drawing a third portion of current from the fourth output or drawing a fourth portion of current from the third output to cause the second circuit to exhibit a second hysteresis, and
- wherein a total amount of hysteresis in the first hysteresis and second hysteresis is configurable based on a ratio between transistor widths in the first circuit and second circuit.
Dependencies are inferred from the claim text.