Field memory self-refreshing device utilizing a refresh clock signal selected from two separate clock signals

A field memory self-refreshing device for refreshing a field memory, comprising:

• reference clock means for generating a reference clock signal;
• reference clock stop determination means, connected to said reference clock means, for determining when said reference clock means has stopped generating said reference clock signal;
• and
• refresh signal generating means, connected to said reference clock means and said reference clock stop determination means, for generating a self-refresh clock signal and a normal refresh clock signal, and having an output for outputting said self-refresh clock signal when said reference clock means has stopped generating said reference clock signal and for outputting said normal refresh clock signal when said reference clock means has not stopped generating said reference clock signal.

A method for refreshing a field memory comprising the steps of:

• (a) generating a reference clock signal;
• (b) generating a normal refresh clock signal;
• (c) generating a self-refresh clock signal;
• (d) determining if the reference cock signal is being generated;
• (e) selecting the normal refresh clock signal as a memory refresh clock signal when the reference clock signal is determined to be generated in said step (d);
• (f) selecting the self-refresh clock signal as the memory refresh clock signal when the reference clock signal is determined not to be generated in said step (d);
• and
• (g) refreshing the field memory using the normal refresh clock signal selected in said step (e) or the self-refresh signal selected in said step (f).