Nonvolatile semiconductor memory device programmable via overlapping pulse signals

1. A nonvolatile semiconductor memory device comprising:

a plurality of memory cells divided into M number of groups (M is an integer);

a decoder for successively selecting each of the M number of groups;

a logic circuit for receiving a clock signal and a mode signal so as to generate a first pulse signal, and

a delay circuit for receiving the first pulse signal so as to generate M number of successive overlapping pulse signals in response to the clock signal,

wherein the memory cells of the M number of groups are configured so as to be programmable in response to the respective M number of successive overlapping pulse signals, and

wherein a pulse width and an overlapping amount of each of the M number of successive overlapping control pulse signals are adjustable by varying a pulse width of the clock signal.

2. The nonvolatile semiconductor memory device of claim 1 , further comprising:

a pump circuit for generating a pumped voltage having a level higher than a power supply in response to the M number of successive overlapping pulse signals;

wherein the memory cells of the M number of groups are configured to be programmable in response to the pumped voltage.

3. The nonvolatile semiconductor memory device of claim 1 , wherein when the pulse width of the clock signal is equal to T, the pulse width of the each of the M number of successive overlapping control pulse signals is equal to 2×T, and the overlapping amount of each of the M number of successive overlapping control pulse signals is equal to T.

4. The nonvolatile semiconductor memory device of claim 1 wherein the delay circuit comprises M number of serial-connected D flip-flops.

5. The nonvolatile semiconductor memory device of claim 1 , wherein the M number of successive overlapping pulse signals are generated in response to a rising edge and a falling edge of the clock signal.