Auto-program circuit for a non-volatile memory device

摘要

An auto-program voltage generator in a non-volatile semiconductor memory is described. The memory has a plurality of floating gate type memory cells, a program circuit for programming selected memory cells, and program verification circuit for verifying whether or not the selected memory cells are successfully programmed. A program voltage is generated by a high voltage generator 10. A trimming circuit 30 detects the level of the program voltage and increases sequentially the program voltage within a predetermined voltage range every time the selected memory cells are not successfully programmed. A comparing circuit 40 compares the detected voltage level with a reference voltage and generates a comparison signal. A high voltage generation control circuit 20 actuates the high voltage generator 10 in response to the comparing signal. In this way, a non-volatile semiconductor memory is provided which is capable of maintaining a uniform threshold voltage of the memory cells to be programmed regardless of variance in operating temperature or power supply voltage. <MATH>