Circuit and method for selecting test self-refresh period of semiconductor memory device
AssigneeHynix Semiconductor Inc.
InventorKyong-Ha Lee
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Abstract
The present invention provides a self-refresh period adaptable for testing cells that are weak against hot temperature stress. An apparatus for controlling a self-refresh operation in a semiconductor memory device includes a first period selector for generating one of a period-fixed pulse signal having a constant period and a period-variable pulse signal having a variable period based on a temperature of the semiconductor memory device in a test mode; and a self-refresh block for performing the self-refresh operation in response to an output of the first period selector.
Claims20
An apparatus for controlling a self-refresh operation in a semiconductor memory device, comprising:
- a first period selector for generating one of a period-fixed pulse signal having a constant period and a period-variable pulse signal having a variable period based on a temperature of the semiconductor memory device in a test mode;
- and
- a self-refresh block for performing the self-refresh operation in response to an output of the first period selector.
A semiconductor memory device for controlling a self-refresh operation, comprising:
- a period comparator for outputting a period comparison signal that maintains an enable state until a period-fixed pulse signal is outputted from an entrance into a self-refresh mode;
- a hot temperature stop controller for combining a period-variable pulse signal having a variable period depending on temperature and the period comparison signal, and generating a hot temperature stop signal when the period-variable pulse signal is generated during an enable period of the period comparison signal, and generating a delayed hot temperature stop signal;
- a second period-fixed pulse generator for generating a second period-fixed pulse signal in which the second period-fixed pulse signal generated just after the enable period of the period comparison signal is removed;
- a first period selector for generating one of a period-fixed pulse signal having a constant period and a period-variable pulse signal having a variable period based on the delayed hot temperature stop signal in a test mode;
- and
- a self-refresh block for performing the self-refresh operation in response to an output of the first period selector.
A method for controlling a self-refresh operation in a semiconductor memory device, comprising the steps of:
- generating one of a period-fixed pulse signal having a constant period and a period-variable pulse signal having a variable period based on a temperature of the semiconductor memory device in a test mode;
- and
- performing the self-refresh operation in response to an output of the first period selector.
Dependencies are inferred from the claim text.