PROGRAM CONTROL CIRCUIT OF FLASH MEMORY DEVICE FOR ADJUSTING VARIABLE VOLTAGE LEVEL OF BIT LINE DURING PROGRAM OPERATION, AND CONTROL METHOD OF THE SAME FOR PREVENTING PUNCH THROUGH PHENOMENON

摘要

PURPOSE: A program control circuit of a flash memory device is provided to prevent the punch through phenomenon between adjacent memory cells that share the source line, and to prevent the over program by controlling and adjusting variable voltage level of bit line during a program operation. CONSTITUTION: A program control circuit of a flash memory device comprises a level detection controller(101) which is enabled or disabled by a first program control signal(PROG), compares a bit line voltage(VBL) of a to-be-programmed memory cell with reference voltage(VREF), and outputs a voltage control signal(CTL) according to the comparison result; a switching controller(102) which outputs a switching bias signal(Vswb1) in response to the voltage control signal(CTL) and a second program control signal(DIN); a current sinker(107) makes the current(Io) flow into a ground in response to a reference bias signal; switching circuits(103, 106) which are switched by the switching bias signals(Vswb1, Vswb2) between the bit line and the current sinker.