Integrated circuit and display device
AssigneeSeiko Epson Corporation
InventorsAkira Morita, Shinya Ukai
Life of this patent
Estimating the term…
Abstract
An integrated circuit includes a capacitance element to be tested and a test circuit in the same semiconductor substrate, the test circuit includes a capacitance element for testing, and a comparison circuit for comparing a voltage of a node with a voltage of a signal, electrically connects another end of the capacitance element to be tested to the node, applies the voltage of the signal to the node in a first period, changes the voltage of the node based on a capacitance ratio of the capacitance element to be tested and the capacitance element for testing, and tests a capacity size of the capacitance element to be tested based on a comparison result of the comparison circuit in a second period after the first period.
Claims14
An integrated circuit, comprising:
- a capacitance element to be tested having one end to which a predetermined voltage is supplied;
- and
- a test circuit including a capacitance element for testing and a comparison circuit for comparing a voltage of an input node of the comparison circuit with a predetermined reference voltage supplied to another node of the comparison circuit, and configured to electrically connect another end of the capacitance element to be tested to the input node of the comparison circuit to:
- apply a first voltage to the input node of the comparison circuit in a first period while the first voltage is also applied to one end of the capacitance element for testing and the first voltage is different from the predetermined voltage supplied to the one end of the capacitance element to be tested,
- apply, in a second period after the first period, a voltage, which is changed from the first voltage, to the input node of the comparison circuit, the voltage being based on a capacitance ratio of the capacitance element to be tested and the capacitance element for testing, and
- test capacitance of the capacitance element to be tested based on a comparison result of the comparison circuit, wherein:
- the capacitance element for testing includes a first capacitance element for testing and a second capacitance element for testing,
- capacitance of the first capacitance element for testing is different from capacitance of the second capacitance element for testing,
- capacitance of the capacitance element to be tested is tested based on a comparison result of the comparison circuit when a voltage change based on the capacitance ratio is caused using the first capacitance element for testing, and a comparison result of the comparison circuit when a voltage change based on the capacitance ratio is caused using the second capacitance element for testing,
- one end of the first capacitance element for testing and one end of the second capacitance element for testing are a same node as the input node of the comparison circuit,
- when the first capacitance element for testing is used by supplying a non-zero positive voltage to another end of the first capacitance element for testing, the second capacitance element for testing is not used by supplying a zero voltage to another end of the second capacitance element for testing, and
- when the second capacitance element for testing is used by supplying a non-zero positive voltage to the another end of the second capacitance element for testing, the first capacitance element for testing is not used by supplying a zero voltage to the another end of the first capacitance element for testing.
Dependencies are inferred from the claim text.