Non-volatile semiconductor memory device with power saving feature

A non-volatile semiconductor memory device, comprising:

• first means for providing an input clock signal;
• a module having circuit components in a feedback loop configuration and being driven by a reference clock signal;
• second means for controllably switching between a first operational state in which the reference clock signal tracks the input clock signal and a second operational state in which the reference clock signal is decoupled from the input clock signal;
• and
• third means for recognizing commands issued by a controller, including an erase command, and varying the operational state of the second means in response to recognizing the erase command;
• wherein when the reference clock signal tracks the input clock signal, the module consumes a first amount of power and wherein when the reference clock signal is decoupled from the input clock signal, the module consumes a second amount of power that is less than the first amount of power.

A system, comprising:

• a controller configured to issue a master clock signal and to issue commands including an erase command;
• and
• a non-volatile semiconductor memory device, which comprises:
• an interface comprising:
• an input port for receiving an input clock signal related to the master clock signal;
• and
• a set of data lines for receiving the commands issued by the controller;
• a module having circuit components in a feedback loop configuration, the module being driven by a reference clock signal;
• a clock control circuit capable of controllably switching between a first operational state in which the reference clock signal tracks the input clock signal and a second operational state in which the reference clock signal is decoupled from the input clock signal;
• and
• a command processing unit configured to recognize the commands issued by the controller and to cause the clock control circuit to switch from the first operational state to the second operational state in response to recognizing the erase command;
• wherein when the reference clock signal tracks the input clock signal, the module consumes a first amount of power and wherein when the reference clock signal is decoupled from the input clock signal, the module consumes a second amount of power that is less than the first amount of power.