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

Image Number 6 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
Push button
Sign language keyboard and sign language searching apparatus using the same
Removable storage device and method for identifying drive letter of the removable storage device
Hybrid fiber constructions to mitigate creep in composites
Electric washing machine
Selective facsimile denial
Squib control circuit
  Randomly Featured Patents
Automatic table locating technique for documents
Erosion barrier for thermal barrier coatings
Pump for moving metal in a bath of molten metal
Apparatus for automatic woodsplitting
Electrode for electric discharge surface treatment, method of electric discharge surface treatment, and apparatus for electric discharge surface treatment
Carburator for a stratified combustion engine with a prechamber
Combined wall mount and electrical outlet box
Partial aortic occlusion devices and methods for cerebral perfusion augmentation
Fiber-optic system with delay line for large dynamic range and low pulse width distortion of initial data bits
Indication device in plan position indication system