Resources Contact Us Home
Threshold voltage adjustment method of non-volatile semiconductor memory device and non-volatile semiconductor memory device

Image Number 2 for United States Patent #6879521.

It is intended to provide a nonvolatile semiconductor memory device which maintains the maximum number of over-erase memory cells which are conductive when adjusting the threshold voltage after data erase by controlling the gate voltage of a memory cell continuously in order to adjust the threshold voltage in a short time and a nonvolatile voltage adjustment method. There is formed a feedback loop for controlling the number of memory cells to be conductive in a memory cell group by controlling a gate voltage generating circuit through a differential amplifier from a drain terminal and the gate voltage generating circuit is controlled by the differential amplifier so as to maintain the drain voltage at a predetermined drain voltage VRF. A variable gate voltage can be controlled continuously by a feedback loop for controlling the variable gate voltage based on a difference voltage between the drain voltage and the predetermined drain voltage. Thus, effective threshold voltage adjustment operation is enabled corresponding to a current supply capacity regardless of the current supply capacity of the drain voltage generating circuit.

  Recently Added Patents
Automatic stop and restart device for an engine
Vehicle front fender
Method and system for producing fluoride gas and fluorine-doped glass or ceramics
Measurement protocol for a medical technology apparatus
Circuit board and display panel assembly having the same
Tab visibility
  Randomly Featured Patents
Portable nail polish holder
Aerosol container with gas-permeable membrane
Method and apparatus for detecting the presence of cancerous and precancerous cells in a smear using native fluorescence spectroscopy
Exposure apparatus, exposure method, and device manufacturing method
Vibration displacement detecting system
Food products and process for producing same
Method and apparatus for removing baseline shifts in a read signal using filters
Stability alignment frame for erecting a portable multi-purpose stand
Multilayer flow electrospray ion source using improved sheath liquid
Vertical wave display panel