Comparator circuit
AssigneeSeiko Epson Corporation
InventorAkira Nakada
Life of this patent
Estimating the term…
Abstract
A window voltage comparator, which determines whether a difference between two voltages is greater or smaller than a set value, is equipped with a first differential pair including a first transistor to which a first input voltage is applied and a second transistor to which a second input voltage is applied, a second differential pair including a third transistor to which a first reference voltage is applied and a fourth transistor to which a second reference voltage is applied, and a comparison circuit that compares the sum of drain currents of the first and fourth transistors with the sum of drain currents of the second and third transistors and thereby determines whether a difference between the first input voltage and the second input voltage is greater or smaller than a set value.
Claims7
A comparator circuit comprising:
- a first differential pair including a first transistor having a gate to which a first input voltage is applied generating a first drain current, and a second transistor having a gate to which a second input voltage is applied generating a second drain current;
- a second differential pair including a third transistor having a gate to which a first reference voltage is applied generating a third drain current, and a fourth transistor having a gate to which a second reference voltage is applied generating a fourth drain current;
- and
- a comparison circuit connected to the first and second differential pairs, and receiving the first, second, third and fourth drains currents, the comparison circuit comparing the sum of at least the first and fourth drain current of the first and fourth transistors and the sum of at least the second and third drain currents of the second and third transistors and based on the comparison, thereby determining and outputting whether a difference between the first input voltage and the second input voltage is greater or smaller than a difference between the first reference voltage and the second reference voltage.
A comparator circuit comprising:
- a first N-channel transistor differential pair including a first N-channel transistor having a gate to which a first input voltage is applied and a second N-channel transistor having a gate to which a second input voltage is applied;
- a first P-channel transistor differential pair including a first P-channel transistor having a gate to which the second input voltage is applied and a second P-channel transistor having a gate to which the first input voltage is applied;
- a first current mixing circuit that obtains the sum of drain currents of the first N-channel transistor and the first P-channel transistor;
- a second current mixing circuit that obtains the sum of drain currents of the second N-channel transistor and the second P-channel transistor;
- a second N-channel transistor differential pair including a third N-channel transistor having a gate to which a first reference voltage is applied and a fourth N-channel transistor having a gate to which a second reference voltage is applied;
- a second P-channel transistor differential pair including a third P-channel transistor having a gate to which the second reference voltage is applied and a fourth P-channel transistor having a gate to which the first reference voltage is applied;
- a third current mixing circuit that obtains the sum of drain currents of the third N-channel transistor and the third P-channel transistor;
- a fourth current mixing circuit that obtains the sum of drain currents of the fourth N-channel transistor and the fourth P-channel transistor;
- and
- a comparison circuit that compares the sum of output currents of the first and fourth current mixing circuits and the sum of output currents of the second and third current mixing circuits and thereby determines whether a difference between the first input voltage and the second input voltage is greater or smaller than a difference between the first reference voltage and the second reference voltage.
Dependencies are inferred from the claim text.