Patent ID: 8605494

Claim:
A semiconductor device comprising a write amplifier adapted to drive a bit line, connected to a selected phase change memory cell, with a first current driving capability and then to drive said bit line to a write voltage, corresponding to data to be written, with a second current driving capability lower than said first current driving capability, wherein said write amplifier comprises a first write amplifier section and a second write amplifier section, said first write amplifier section and said second write amplifier section jointly provide said first current driving capability, said second write amplifier section provides said second current driving capability, said first write amplifier section comprises a first switch and a first current trimming portion connected in series between a high-potential side power supply and said bit line, said first switch adapted to be turned on or off in response to an input signal and said first current trimming portion adapted to limit a passing current depending on a voltage of said bit line, and said second write amplifier section comprises a second switch and a second current trimming portion connected in series between said bit line and said high-potential side power supply, said second switch adapted to be turned on or off in response to said input signal and said second current trimming portion adapted to limit a passing current to realize said second current driving capability.