Patent ID: 8120414

Claim:
A low noise current source, comprising: first and second current output terminals; first and second voltage input terminals adapted to couple a voltage source; an amplifying device comprising a device first input terminal, a device second input terminal, and a device output terminal, said device output terminal coupled to said first current output terminal, and said first voltage input terminal adapted to receive a time-varying noise signal which produces a time-varying noise current; a bias circuit having a first resistive circuit and a second resistive circuit, said first resistive circuit coupled between said first voltage input terminal and said device first input terminal, and said second resistive circuit coupled between said device first input terminal and said second voltage input terminal; and a first bypass circuit coupled between said first voltage input terminal and said device first input terminal in parallel with said first resistive circuit, said first bypass circuit configured to provide a substantially high electrical resistance and substantially low electrical impedance to cause said amplifying device to cancel at least a portion of said time-varying noise current before said time-varying noise current flows out of said low noise current source.