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

Image Number 9 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
Light-emitting diode package and method for manufacturing the same
Electric discharge machining hole drilling
Suspension with flexure having laminated structure and bonding pads on opposing surfaces thereof, and head gimbal assembly and disk drive unit with the same
Haworthia plant named `CAPETOWN`
Systems and methods for programming an RFID reader
Lubricant supplying device, process cartridge, and image forming apparatus
Method and system for weighted fair queuing
  Randomly Featured Patents
Multiple contact switch
Branching device for an electric line
Image bearing member, image forming method, and image forming apparatus
Dovetail siding and corner block attachment method
Seizure sensing and detection using an implantable device
Plural channel superconducting filter circuit having release of resonance frequency degeneracy and usable in radio frequency equipment
Pressure vessel especially for a nuclear reactor
Flexible laminates bonded with water-based laminating vehicles and laminating adhesives
Circulating electrolyte electrochemical cell having gas depolarized cathode with hydrophobic barrier layer
Composite dental abutment