公开(公告)号：US20210278461A1

公开(公告)日：2021-09-09

申请号：US17189984

申请日：2021-03-02

Applicant: STMicroelectronics SA

Inventor： Ricardo GOMEZ GOMEZ ,  Sylvain CLERC

IPC: G01R31/317 ,  G01R31/3177 ,  H03K3/03

Abstract: A ring oscillator includes a chain of logic components. A storage element is associated with each logic component and configured to store a state of an output of the logic component to which the storage element is associated. A first circuit counts state transitions of an output of a given logic component of the chain. A second circuit synchronizes each storage with a clock signal. A third circuit determines a number of logic components crossed by a state transition between two edges of the clock signal. This determination is made based on the counted number of state transitions and on the stored states of the outputs.

公开(公告)号：US20210096183A1

公开(公告)日：2021-04-01

申请号：US17031716

申请日：2020-09-24

Applicant: STMICROELECTRONICS SA

Inventor： Ricardo GOMEZ GOMEZ ,  Sylvain CLERC

IPC: G01R31/319 ,  G01R31/3185 ,  G01R31/3193 ,  G01R31/317

Abstract: A method tests at least three devices, each device including a test chain having a plurality of positions storing test data. The testing includes comparing test data in a last position of the test chain of each of the devices, and shifting test data in the test chains of each of the devices and storing a result of the comparison in a first position of the test chains of each of the devices. The comparing and the shifting and storing are repeated until all the stored test data has been compared. The at least three devices may have a same functionality and a same structure.